JP2003320617A - Triacetyl cellulose film having hard coat layer and antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a triacetyl cellulose film having a hard coat layer having excellent adhesion adaptable to the exterior or interior surface of an image display device, and an antireflection film using the same. <P>SOLUTION: The triacetyl cellulose film has the hard coat layer laminated to the surface thereof. The hard coat layer is formed using a composition containing 100 pts.wt. of an ionizing radiation curable polyfunctional acrylic resin, and 10-45 pts.wt. of an ionizing radiation curable phosphoric acid- containing (meth)acrylate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triacetyl cellulose film having a hard coat layer having excellent adhesiveness, which can be used as an exterior surface or an interior surface of an image display device, and an antireflection film using the same.

[0002]

2. Description of the Related Art A triacetyl cellulose film having a hard coat layer is used as an exterior surface or an interior surface of an image display device because it has excellent moldability and light transmittance. In particular, an antireflection film having an antireflection layer provided on the hard coat layer is used for a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence display (ELD), and an inter-cathode display (CR).
T) and other image display devices.

In recent years, the environment in which the image display device is used has spread to the outdoors, and it is desired that the triacetyl cellulose film having a hard coat layer also has improved durability so that it can be used outdoors. In particular, in the antireflection film used for the exterior of the display device, the adhesion between the triacetyl cellulose film and the hard coat layer or the hard coat layer and the antireflection layer by being continuously used outdoors and exposed to ultraviolet rays or the like. There is a problem in that the adhesiveness with and the peeling damage may occur on the surface of the display device due to unexpected scratches, making it unusable as a product.

On the other hand, there has been proposed a method for improving the adhesion to the hard coat layer by using a highly compatible ketone solvent on the surface of the triacetyl cellulose film. However, this method has a problem that the triacetyl cellulose film may be whitened to impair the transparency. JP-A-9-302144
The publication discloses a method of improving adhesion to a triacetyl cellulose film by blending a cellulosic resin in a hard coat layer. However, this method has a problem that the adhesion becomes insufficient when exposed to light such as ultraviolet rays for a long time.

[0005]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is a triacetyl cellulose film having a hard coat layer having excellent adhesion which can be used for the exterior surface or interior surface of an image display device, and the same. It is intended to provide an antireflection film used.

[0006]

The present invention is a film comprising a triacetyl cellulose film and a hard coat layer formed on the surface of the triacetyl cellulose film, wherein the hard coat layer is cured by ionizing radiation. A triacetyl cellulose film having a hard coat layer, which is obtained by using a composition containing 100 parts by weight of a polyfunctional acrylic resin of type Ionizing Radiation and 10-45 parts by weight of a phosphoric acid-containing (meth) acrylate curable by ionizing radiation. The present invention is described in detail below.

The present invention is a triacetyl cellulose film having a hard coat layer. The triacetyl cellulose film is not particularly limited, but a film containing an ultraviolet absorber is preferably used in order to improve weather resistance. The thickness of the triacetyl cellulose film is not particularly limited, but for use in optical applications,
The preferred lower limit is 20 μm, the upper limit is 300 μm, the more preferred lower limit is 40 μm, and the upper limit is 80 μm.

The hard coat layer comprises a composition containing an ionizing radiation curable polyfunctional acrylic resin and an ionizing radiation curable phosphoric acid-containing (meth) acrylate. The ionizing radiation-curable polyfunctional acrylic resin is a polyfunctional acrylic resin that is crosslinked and cured by irradiation with ionizing radiation. Examples of the ionizing radiation-curable polyfunctional acrylic resin include polyester acrylate polyfunctional acrylic resin, polyether acrylate polyfunctional acrylic resin, polyurethane acrylate polyfunctional acrylic resin, epoxy acrylate polyfunctional acrylic resin, and the like. You can Among them, polyester acrylate polyfunctional acrylic resin,
At least one selected from the group consisting of a polyurethane acrylate polyfunctional acrylic resin and an epoxy acrylate polyfunctional acrylic resin is suitable.

Specific examples of the ionizing radiation-curable polyfunctional acrylic resin include dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, and the like.
Examples thereof include trimethylolpropane triacrylate, a polyvalent isocyanate, and a urethane acrylate obtained by reacting a hydrogen group-containing acrylate.

Ionizing radiation-curable phosphoric acid-containing (meth)
Acrylate has a structure represented by the following general formula (1).

[Chemical 1]

In the formula, 1 or 2 of R ¹ , R ² and R ³ represents H. By containing the above-mentioned ionizing radiation-curable phosphoric acid-containing (meth) acrylate, the adhesion between the obtained hard coat layer and the triacetyl cellulose film is improved.

Ionizing radiation-curable phosphoric acid-containing (meth)
As acrylate, monofunctional phosphate group-containing (meth)
Examples thereof include acrylate, bifunctional phosphoric acid group-containing (meth) acrylate, and a mixture thereof. Specific examples of the ionizing radiation-curable phosphoric acid-containing (meth) acrylate include ethyl (meth) acrylate acid phosphate, 3-chloro-2-acidphosphoxypropyl (meth) acrylate, and polyoxyethylene glycol (meth). ) Acrylate acid phosphate, 2-hydroxyethyl (meth) acrylate acid phosphate, 2- (meth) acryloyloxyethyl caproate acid phosphate, and the like. Among these ionizing radiation curable phosphoric acid-containing (meth) acrylates, commercially available products include, for example, Phosmer M (manufactured by Unichemical Co., Ltd.), PM-2 (manufactured by Nippon Kayaku Co., Ltd.), P-1A, P. -2A, P-1M, P-2M (manufactured by Kyoeisha Chemical Co., Ltd.) (all of which are ethyl (meth) acrylate acid phosphates); Phosmer CL (manufactured by Unichemical Co., 3-chloro-2-acid phosphoxypropyl (meta). ) Acrylate), Phosmer PE (manufactured by Unichemical, polyoxyethylene glycol (meth) acrylate acid phosphate), JAP-514 (manufactured by Johoku Chemical Co., Ltd., 2-hydroxyethyl (meth) acrylate acid phosphate), PM-21 (Japan). Made by Kayaku Co.,
2- (meth) acryloyloxyethyl caproate acid phosphate) and the like.

The above composition preferably further contains a cellulosic resin. By containing a cellulosic resin, the affinity between the resulting hard coat layer and the triacetyl cellulose film is improved and the adhesion is improved, and the adhesion with the antireflection layer is increased by saponification as described below. Can also be improved. Examples of the cellulose-based resin include nitrocellulose, methyl cellulose, acetyl cellulose, cellulose acetate propionate, and ethyl hydroxyethyl cellulose.

In the case where the composition contains an ionizing radiation-curable polyfunctional acrylic resin and an ionizing radiation-curable phosphoric acid-containing (meth) acrylate, the compounding amounts of the above-mentioned components in the composition are the ionizing radiation. The preferable lower limit of the compounding amount of the ionizing radiation-curable phosphoric acid-containing (meth) acrylate with respect to 100 parts by weight of the curable polyfunctional acrylic resin layer is 1
0 parts by weight, the upper limit is 45 parts by weight. If it is less than 10 parts by weight, the effect of improving the adhesion between the obtained hard coat layer and the triacetyl cellulose film cannot be obtained, and if it exceeds 45 parts by weight, the surface of the hard coat layer becomes sticky and it becomes difficult to use. , The chemical resistance may decrease. The preferred lower limit is 15 parts by weight and the upper limit is 35 parts by weight.

When the composition contains an ionizing radiation-curable polyfunctional acrylic resin, an ionizing radiation-curable phosphoric acid-containing (meth) acrylate, and a cellulosic resin, the ionizing radiation-curable polyfunctional acrylic resin is used. Layers 60-95
Mixture of 1 part by weight and 5 to 40 parts by weight of cellulosic resin 1
It is preferable to mix 10 to 45 parts by weight of the ionizing radiation-curable phosphoric acid-containing (meth) acrylate with respect to 00 parts by weight. If the blending amount of the cellulosic resin is less than 5 parts by weight, the effect of improving the adhesion between the obtained hard coat layer and the triacetyl cellulose film may not be obtained, or
The decrease in contact angle after saponification is small and it becomes difficult to form the antireflection layer. Cellulosic resin content is 40
If it exceeds the weight part, the scratch resistance of the obtained hard coat layer may be inferior.

The method for forming the hard coat layer on the triacetyl cellulose film is not particularly limited. For example, a method for coating the composition on the triacetyl cellulose film without a solvent or a method for coating the composition on a solvent. Examples thereof include a method of coating after diluting and then coating on a triacetyl cellulose film, a method of coating after drying, and a method of curing. In the case of coating without the solvent, the viscosity may be adjusted with a reactive diluent composed of a low molecular weight acrylic resin having a functional group. Also, when diluting with a solvent, a material that does not dissolve or whiten the triacetyl cellulose film such as toluene is selected.

The coating method is not particularly limited,
For example, a method using an offset gravure, a gravure coater, a micro gravure coater, a Mayer bar and the like can be mentioned.

As a method of curing the above-mentioned coated and dried composition, for example, a method of irradiating with an electron beam or an ultraviolet ray can be mentioned. The method of irradiating the ultraviolet rays is not particularly limited, and examples thereof include a method using a high pressure mercury lamp, a metal halide lamp, an electrodeless fusion lamp, and the like.

The thickness of the hard coat layer is not particularly limited, but the preferable lower limit is 1 μm and the upper limit is 10 μm, and the more preferable lower limit is 3 μm and the upper limit is 7 μm in order to secure a certain hardness.

The triacetyl cellulose film having the hard coat layer of the present invention thus obtained has extremely excellent adhesion between the hard coat layer and the triacetyl cellulose film, and is exposed to ultraviolet rays or the like outdoors for a long period of time. Even if it is done, it hardly peels off.

An antireflection film can be prepared by laminating an antireflection layer on the hard coat layer of the triacetyl cellulose film having the hard coat layer of the present invention. The method for laminating the antireflection layer on the hard coat layer is not particularly limited, but a method of forming the antireflection layer by a method such as vacuum deposition after saponifying the hard coat layer by alkali treatment is preferable. By saponifying the hard coat layer, the leakage property due to saponification of the cellulosic resin is improved, that is, the contact angle is reduced, and thus the adhesion with the antireflection layer is improved. Such an antireflection film obtained by saponifying the surface of the hard coat layer of the triacetyl cellulose film having the hard coat layer of the present invention by alkali treatment, and laminating the antireflection layer on the hard coat layer having the surface saponified is also provided. , Is one of the present invention.

The saponification method is not particularly limited, and examples thereof include a method of immersing the film in an aqueous solution of potassium hydroxide or the like, neutralizing with a hydrochloric acid or the like, and then washing with water.

The antireflection layer is made of metal oxide.
Consisting of a high refractive index layer and a metal oxide or metal fluoride
The low-refractive index layer is two layers so that the low-refractive index layer is the outermost surface.
It is preferable that the layers are laminated. The high refractive index layer
As the metal oxide formed, for example, ZrO₂, Ti
O₂, SnO₂, In₂O₃, ITO, and the like. the above
As a metal oxide or a metal fluoride that constitutes the low refractive index layer
For example, Al ₂O₃, SiO₂, MgF₂Etc.
Be done. A method for forming an antireflection layer on the hard coat layer
The method is not particularly limited, and examples thereof include vacuum deposition and spattering.
Use known methods such as tarring and plasma CVD
You can

The antireflection film of the present invention has a synergistic effect of improving the adhesion of the phosphoric acid-containing (meth) acrylate contained in the hard coat layer and the effect of improving the adhesion by saponifying the cellulose resin. The adhesion between the coat layer and the antireflection layer is extremely high, and even when used outdoors for a long time, the hard coat layer and the triacetyl cellulose film,
Alternatively, the hard coat layer and the antireflection layer hardly separate from each other. The antireflection film of the present invention is used for a liquid crystal display (LCD), a plasma display panel (PD).
P) Electroluminescence display (ELD)
And an image display device such as an inter-cathode display device (CRT).

[0025]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 As a polyfunctional acrylic resin curable with ionizing radiation, 60 parts by weight of dipentaerythritol hexaacrylate and 40 parts by weight of pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, and phosphoric acid-containing (meth) acrylate resin. As the above, a coating solution was prepared by diluting a composition obtained by mixing 25 parts by weight of 2-methacryloyloxyethyl acid phosphate with toluene to a solid content of 50 wt%. The obtained coating solution is applied to a triacetyl cellulose film having a thickness of 80 μm, dried, and then irradiated with ultraviolet rays at an irradiation energy of 300 mJ using an ultraviolet irradiation device of a high pressure mercury lamp to cure the film.
A triacetyl cellulose film having a hard coat layer with a thickness of 5 μm was obtained.

Example 2 50 parts by weight of dipentaerythritol hexaacrylate and 30 parts by weight of pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer as ionizing radiation curable polyfunctional acrylic resin, and cellulose acetate butyrate as cellulose resin. 20 parts by weight of a rate (acetylated 2% by weight, butylated 53% by weight, hydroxylylated 1.5% by weight, glass transition temperature 85 ° C., average molecular weight 16000) and phosphoric acid-containing (meth) acrylate resin as 2 parts by weight.
-Methacryloyloxyethyl acid phosphate 25
A mixture of 1 part by weight and 50 parts by weight of solid composition is added to toluene.
A coating solution diluted so as to be t% was prepared. The obtained coating solution is applied to a triacetylcellulose film having a thickness of 80 μm, dried, and then irradiated with ultraviolet rays at an irradiation energy of 300 mJ using an ultraviolet irradiation device of a high pressure mercury lamp to cure the film, thereby increasing the thickness. A triacetyl cellulose film having a hard coat layer having a thickness of 5 μm was obtained.

(Example 3) The triacetyl cellulose film having the hard coat layer obtained in Example 1 was replaced with 2
After dipping in N potassium hydroxide aqueous solution at 60 ° C for 90 seconds, 30
It was washed with water at 60 ° C for 60 seconds, immersed in 1N hydrochloric acid at 30 ° C for 60 seconds for neutralization, and further washed with water at 30 ° C for 60 seconds to saponify. The contact angle of the surface of the hard coat layer before and after saponification was measured to be 65 degrees before saponification and 45 degrees after saponification.
It was degree. Then, as an anti-reflection layer, by vapor deposition or sputtering in order of _{TiO 2, SiO 2, TiO 2} , SiO 2, the average reflectance to the wavelength 400 to 700 nm 0.
It laminated so that it might be 4%, and produced the antireflection film. A schematic diagram showing the obtained antireflection film is shown in FIG.

(Example 4) Using the triacetyl cellulose film having the hard coat layer obtained in Example 2, an antireflection film was prepared in the same manner as in Example 3. The contact angle of the surface of the hard coat layer before and after saponification was measured and found to be 65 degrees before saponification and 30 degrees after saponification.

Comparative Example 1 A triacetyl cellulose film having a hard coat layer was obtained in the same manner as in Example 1 except that the hard coat layer did not contain a phosphoric acid-containing (meth) acrylate resin.

Comparative Example 2 A triacetyl cellulose film having a hard coat layer was obtained in the same manner as in Example 2 except that the hard coat layer did not contain a phosphoric acid-containing (meth) acrylate resin.

Comparative Example 3 Using the triacetylcellulose film having the hard coat layer obtained in Comparative Example 1, an antireflection film was produced in the same manner as in Example 3. The contact angle of the surface of the hard coat layer before and after saponification was measured and found to be 70 degrees before saponification and 50 degrees after saponification.

Comparative Example 4 An antireflection film was prepared in the same manner as in Example 3, using the triacetylcellulose film having the hard coat layer obtained in Comparative Example 2. The contact angle of the surface of the hard coat layer before and after saponification was measured and found to be 70 degrees before saponification and 35 degrees after saponification.

Regarding the triacetyl cellulose film or the antireflection film having a hard coat layer produced in Examples 1 to 4 and Comparative Examples 1 to 4, JIS K 5
Based on 400, 150 hours and 300 using Sunshine Carbon Arc (manufactured by Suga Test Instruments Co., Ltd., without water spray)
After irradiating with ultraviolet rays for a period of time, a cut is made on the film surface with a cutter knife, and a 1 mm x 1 mm grid is made 10
0 blocks were prepared, a tape peeling test was performed using cellophane tape, and the light resistance was evaluated by the number of blocks which were not peeled out of 100 blocks. The results are shown in Table 1.

[0035]

[Table 1]

[0036]

According to the present invention, there is provided a triacetyl cellulose film having a hard coat layer having excellent adhesion which can be used on the exterior surface or interior surface of an image display device, and an antireflection film using the same. it can.

[Brief description of drawings]

FIG. 1 is a schematic view showing an antireflection film produced in Examples.

Claims (3)

[Claims] 1. A film comprising a triacetyl cellulose film and a hard coat layer formed on the surface of the triacetyl cellulose film, wherein the hard coat layer is an ionizing radiation curable polyfunctional acrylic resin 1.
A triacetyl cellulose film having a hard coat layer, comprising a composition containing 100 parts by weight and 10 to 45 parts by weight of an ionizing radiation-curable phosphoric acid-containing (meth) acrylate. 2. A film comprising a triacetyl cellulose film and a hard coat layer formed on the surface of the triacetyl cellulose film, wherein the hard coat layer comprises ionizing radiation curable polyfunctional acrylic resin layers 60 to 60. A composition containing 100 parts by weight of a mixture of 95 parts by weight and 5 to 40 parts by weight of a cellulosic resin, and 10 to 45 parts by weight of an ionizing radiation-curable phosphoric acid-containing (meth) acrylate. A triacetyl cellulose film having a hard coat layer. 3. The surface of the hard coat layer of the triacetyl cellulose film having the hard coat layer according to claim 1 or 2 is saponified by alkali treatment, and an antireflection layer is laminated on the saponified hard coat layer. An antireflection film characterized by being formed.