JPH07151902A - Plastic film for optical material having hard coating layer to prevent occurrence of interference fringes, its production and antireflection film - Google Patents

Abstract

PURPOSE:To prevent occurrence of interference fringes between a base plastic film and a hard coating layer by using an ionizing radiation-setting type resin containing metal oxide ultrafine particles as the hard coating layer in which enough bonding property to the resin is positively given to the metal oxide ultrafine particles so that good dispersibility of particles in the resin is obtd., a coating film having high mechanical strength is obtd., the metal oxide ultrafine particles have resistance against acid and alkali, and deterioration of the coating film due to acid or alkali is prevented. CONSTITUTION:A silicon oxide film is formed on a metal oxide ultrafine particle and the particle surface is treated with a coupling agent so that the particle has bonding property with a resin. The treated metal oxide ultrafine particles are dispersed in an ionizing radiation-setting type resin. The obtd. liquid is applied on a base plastic film 1 to form a hard coating layer 2. Further, an antireflection film 3 may be formed thereon by vapor deposition or coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic film to be adhered to optical materials such as lenses, displays for personal computers and word processors, other commercial displays, curve mirrors, goggles, window glasses, etc., for the purpose of protection.
In particular, the present invention relates to a plastic film having the effect of preventing the occurrence of interference fringes of the plastic film and having the hard property and the chemical resistance.

[0002]

2. Description of the Related Art Conventionally, optical materials such as lenses, displays for personal computers and word processors, and other commercial displays, curve mirrors, goggles, window glasses, etc. are made of scratch-resistant transparent plastic to prevent scratches. The film was attached. Such plastic films include
On the highly transparent polyethylene terephthalate (PET) film, an ionizing radiation curable resin such as an electron beam curable resin or an ultraviolet curable resin having a scratch resistance effect, or a hard coat layer of a siloxane thermosetting resin is formed. It had been.

Incidentally, the PET film has a refractive index of 1.
62, which is higher than the refraction of ordinary resins, whereas the refraction index of the resin used for the hard coat layer is, for example, in the case of an acrylic resin ionizing radiation curable resin, Is as low as 1.49, and the refractive index of both is 0.
Since there is a difference of 13, when this film is viewed under a fluorescent lamp or the like, there is a disadvantage that rainbow-like interference fringes occur. When such interference fringes are generated, it is usually said that the difference in refractive index between the hard coat layer and the base film is ± 0.03 or more.

Focusing on making the refractive index of the hard coat layer close to the refractive index of the PET film for the purpose of preventing the occurrence of such interference fringes, the ionizing radiation curing containing the metal oxide ultrafine particles having a high refractive index is performed. The mold resin is applied on a high refractive index film such as PET film and cured to form a hard coat layer, or a siloxane thermosetting resin containing high refractive index metal oxide ultrafine particles is applied. Then, it was cured to form a hard coat layer.

When these metal oxide ultrafine particles having a high refractive index are contained in these resins, the surface of the metal oxide ultrafine particles is hydrophilic, whereas the resin is hydrophobic. The dispersibility of ultrafine oxide particles in resin is poor, and even if they are dispersed, the ultrafine metal particles have weak bondability with the resin, so the mechanical strength of the coated film is low, and the amount added There was also the problem of being limited.

In order to solve such a problem, the surface of the ultrafine metal oxide particles is directly treated with a coupling agent to impart a bondability with the resin, whereby the dispersibility in the resin and the mechanical properties of the coating film are improved. There was a proposal to improve the physical strength.

[0007]

However, even when the surface of the above-mentioned conventional metal oxide ultrafine particles is directly treated with a coupling agent to impart a bondability to a resin, the metal oxide ultrafine particles of the coupling agent are provided. In some cases, the adhesion rate to the resin was low, and it was not possible to impart sufficient bondability with the resin, so that it was not possible to sufficiently disperse it in the resin.
Then, when the amount of the ultrafine metal oxide particles added is increased, there has been a problem that the mechanical strength of the obtained coating film becomes low.

Further, when the coating film formed by adding the ultrafine metal oxide particles to the resin is exposed to acid or alkali,
There have been problems such as erosion at the interface between the ultrafine metal oxide particles and the resin, which deteriorates the coating film, and the ultrafine metal oxide particles being attacked by acid or alkali to cause deterioration such as whitening. Such deterioration of the coating film and the metal oxide ultrafine particles is caused by, for example,
This is a particular problem when ultrafine metal oxide particles are used in a plastic film used as an optical material such as an antireflection film.

Therefore, the present invention improves the sufficient dispersibility of the ultrafine metal oxide particles in the resin by positively imparting sufficient bonding property with the resin to the ultrafine metal oxide particles. It is possible to obtain a coating film having high mechanical strength even if the amount of ultrafine metal oxide particles added to the resin is increased,
Moreover, the ultrafine metal oxide particles themselves impart resistance to acid or alkali, and also prevent the acid or alkali from entering the interface between the resin and the ultrafine metal oxide particles. By forming a hard coat layer using an ionizing radiation curable resin containing ultrafine particles,
An object of the present invention is to provide a plastic film for an optical material having a hard coat layer that prevents the generation of interference fringes, a method for producing the same, and an antireflection film.

[0010]

In order to solve the above-mentioned problems, the present invention forms a silicon oxide film on metal oxide ultrafine particles and further treats the surface with a coupling agent to form a resin. Obtaining metal oxide ultrafine particles having a binding property, then dispersing the metal oxide ultrafine particles in an ionizing radiation curable resin, and then using the obtained metal oxide ultrafine particle dispersed ionizing radiation curable resin as a base plastic film A method for producing a plastic film for an optical material having a hard coat layer for preventing the generation of interference fringes, characterized by being coated on the top.

Further, according to the present invention, by laminating an antireflection layer on the above plastic film for optical materials,
An antireflection film can be provided. For such an antireflection layer, a thin film having a refractive index lower than that of the underlying hard coat layer, such as a metal, a metal oxide, or an inorganic substance is deposited by sputtering, plasma CVD, or the like to form a single layer or a multilayer. Formed or low refractive index MgF ₂ , Si
It can be formed by a single-layer or multi-layer coating of a low refractive index resin composition containing an inorganic material such as O ₂ or a metal material.

In the present invention, when a silicon oxide film is formed on ultrafine metal oxide particles and further treated with a coupling agent, the introduction of a hydrophobic group into the ultrafine metal oxide particles becomes more reliable, and Sufficient dispersibility of the ultrafine oxide particles in the ionizing radiation-curable resin is obtained, and a coating film having high mechanical strength can be obtained. Moreover, the ultrafine metal oxide particles have the effect of preventing deterioration even with respect to acid or alkali. The reason is probably that the case where the silicon oxide film is formed has more hydrophilic groups than the hydrophilic groups present on the surface of the ultrafine metal oxide particles, and therefore the coupling agent is It is considered that this is because more binding occurs and the binding property with the resin increases.

Silicon oxide film: A method for forming a silicon oxide film on the surface of ultrafine metal oxide particles includes a method of adsorbing and growing on the surface of ultrafine particles using SiO ₂ sol. The amount of SiO ₂ sol added is 10
0 to 50 parts by weight, preferably 10 to 30 parts by weight, relative to 0 parts by weight. The particle size of the SiO ₂ sol is about 5 nm.

Ultrafine metal oxide particles: The ultrafine metal oxide particles used in the present invention have a refractive index when the ultrafine metal oxide particles are dispersed in an ionizing radiation curable resin to form a coating film. A material whose refractive index can be adjusted to be equal to that of the base plastic film is selected. For example, the base plastic film is a polyethylene terephthalate film (refractive index: 1.62),
When the ionizing radiation-curable resin of the hard coat layer formed on the base plastic film is an acrylic resin-based ionizing radiation-curable resin (refractive index: 1.49), the metal oxide ultrafine particles used are, for example, , Sb ₂ O ₅ (refractive index: 1.68), TiO ₂ (refractive index: 2.3 to ₂ .
7), Y ₂ O ₃ (refractive index: 1.87), ZrO ₂ (refractive index: 2.05), SnO ₂ (refractive index: 1.90), IT
O (that is, indium-tin oxide, refractive index: 2.0)
0), La ₂ O ₃ (refractive index: 1.95), Al ₂ O
₃ (refractive index: 1.63) or other metal oxide ultrafine particles, or a solid solution of SnO ₂ and WO ₃ (refractive index: 1.7
The metal oxide ultrafine particles of 6) (that is, those obtained by melting and mixing these two kinds of metal oxides and then forming ultrafine particles) can be mentioned, and the addition amount of these metal oxide ultrafine particles is adjusted. This makes it possible to adjust the refractive index of the base plastic film and that of the hard coat layer to be the same.

The amount of ultrafine metal oxide particles added to the ionizing radiation-curable resin can be from 0 (not including 0) to 300 parts by weight with respect to 100 parts by weight of the ionizing radiation-curable resin.

Coupling agent: Silane coupling agents, titanate-based coupling agents, alumina-based coupling agents are used for imparting resin-binding properties to the metal oxide ultrafine particles having a silicon oxide film formed thereon. A coupling agent or the like is used. The amount of these coupling agents added is 0 (not including 0) to 30 parts by weight, based on 100 parts by weight of the metal oxide ultrafine particles on which the silicon oxide film is formed.
Desirably, it is 0 (not including 0) to 10 parts by weight.

Hard coat layer: The resin forming the hard coat layer in the present invention is an ionizing radiation curable resin which is cured by ultraviolet rays or electron beams. The electron beam curable resins include the following resins. Preferably, those having an acrylate-based functional group, for example, relatively low molecular weight polyester resin, polyether resin,
Acrylic resin, epoxy resin, urethane resin, alkyd resin, spiro acetal resin, polybutadiene resin,
Polythiol polyene resin, oligomer or prepolymer such as (meth) acrylate of polyfunctional compound such as polyhydric alcohol, and ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone as a reactive diluent. And monofunctional monomers such as trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth). Acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth)
Those containing a relatively large amount of acrylate or the like can be used.

Furthermore, in order to use the above electron beam curable resin as an ultraviolet curable resin, a photopolymerization initiator is added in the resin.
Acetophenones, benzophenones, Michler's benzoyl benzoate, α-amyloxime ester, tetramethyl thiuram monosulfide, thioxanthone, and a mixture of n-butylamine, triethylamine, tri-n-butylphosphine, etc. as photosensitizers You can Particularly in the present invention, it is preferable to mix urethane acrylate as the oligomer and dipentaerythritol hexaacrylate as the monomer.

Antireflection layer: An antireflection film can be obtained by further forming an antireflection layer on the plastic film having a hard coat layer obtained as described above. In order to form such an antireflection layer, an inorganic material such as MgF ₂ or SiO ₂ having a low refractive index,
A thin film is formed of a metal material by vapor deposition, sputtering, plasma CVD, or the like, or a low refractive index MgF.
₂ , a single layer or multiple layers of a coating film of a low refractive index resin composition containing an inorganic material such as SiO ₂ or a metal material.

[0020]

【Example】

[Example 1] 20 parts by weight of SiO ₂ sol (Nissan Chemical Co., Ltd., particle size 5 nm) was added to 100 parts by weight of Sb ₂ O ₅ sol (AIP-130S: trade name, Nissan Chemical Co., Ltd. particle size 10 to 30 nm). the SiO ₂ ultrafine particles are adsorbed to the Sb ₂ O ₅ ultrafine particles surface, to obtain a sol to form a SiO ₂ film on Sb ₂ O ₅ ultrafine particles surface. 200 parts by weight of this sol was added to a UV-curable acrylate resin (X-12-2400: trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) to obtain a PET film (HP
-7: Brand name, manufactured by Teijin Ltd., thickness 100 μm) and film thickness 3 μ
It is coated so that it becomes m / dry, and an electron beam (4Mrad,
The coating film was cured by irradiation with 10 m / min). M on this film
An antireflection film was obtained by forming a vapor deposition film of aF ₂ by a vacuum vapor deposition method so as to have a film thickness of 1000 Å.

FIG. 1 is a sectional view showing the layer structure of the antireflection film obtained in Example 1. In FIG.
1 is a base plastic film, 2 is a hard coat layer,
3 is an antireflection layer.

Example 2 As a base film, a PET film (HP-7: trade name, manufactured by Teijin, thickness 125 μm,
The light transmittance at 550 nm is 87.5%), and S
Except that the amount of Sb ₂ O ₅ ultrafine particles having an iO ₂ film formed on it was changed to the ultraviolet curable acrylate resin,
An antireflection film was manufactured under the same conditions as in Example 1.

The thickness of the obtained antireflection film, the substrate adhesion (%), the light transmittance at 550 nm, the MgF ₂
The following Table 1 shows the results of measuring the vapor deposition adhesiveness (%) of Example 1 and the light transmittance of the deposited film at 550 nm.

[0024]

[Table 1] According to Table 1, as the amount of Sb ₂ O ₅ ultrafine particles added to the ultraviolet curable acrylate-based resin increased, the adhesion to the base plastic film, the light transmittance of the obtained antireflection film, MgF ₂ Deposition adhesion (%) of 55
It can be seen that the vapor deposition film light transmittance at 0 nm is increased.

Example 3 A solid solution sol (HIS-30: trade name, manufactured by Nissan Kagaku Co.) consisting of SnO ₂ and WO ₃ was prepared.
Ionizing radiation curable siloxane-based acrylate resin (X-
12-2400: 150 parts by weight of the product name, manufactured by Shin-Etsu Chemical Co., Ltd., and the obtained resin composition was added to a PET film (HP).
-7: Brand name, manufactured by Teijin Ltd., thickness 100 μm) and film thickness 3 μ
It is coated so that it becomes m / dry, and an electron beam (4Mrad,
The coating film was cured by irradiation with 10 m / min). An antireflection film was obtained by forming a vapor deposition film of MaF ₂ on the cured coating film by a vacuum vapor deposition method so as to have a film thickness of 1000Å.

[Example 4] A sol (AMT-130S: trade name, manufactured by Nissan Kagaku Co., Ltd.) having a solid content of 30% by weight of a solid solution composed of SnO ₂ and WO ₃ was converted into an ultraviolet-curable siloxane-based acrylate resin (X-12-). 2400: 30% by weight of xylene diluted solids (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), and added amounts of 10% by weight, 25% by weight, 30% by weight, 40% by weight, 50% by weight, 60% by weight and 65% by weight, respectively. %, 70% by weight, and each of the obtained resin compositions was coated on a PET film (HP-7: trade name, manufactured by Teijin, thickness 75 μm) to a film thickness of 3 μm / dry. At a line speed of 2.5 m / min and a drying temperature of 60 ° C., 160 W of ultraviolet light was irradiated to form a hard coat layer. On each of these cured coating films, MaF ₂ was formed into a vapor deposition film by a vacuum vapor deposition method so as to have a film thickness of 1000 Å to obtain each antireflection film.

The surface hardness of each antireflection film obtained,
Substrate adhesion (%), total light transmittance (%), haze value (%), light transmittance at 550 nm, MgF ₂ vapor deposition film adhesion (%), vapor deposition film light transmittance at 550 nm (%), The vapor deposition film haze value (%), the vapor deposition film light transmittance (%) at 550 nm, and the vapor deposition film surface hardness were measured, and the results are shown in Table 2 below.

[0028]

[Table 2] According to Table 2, when the amount of the solid solution of SnO ₂ and WO ₃ added to the resin is more than 40% by weight and less than 70% by weight, the dispersibility of the ultrafine metal oxide particles and the obtained hard It can be seen that the surface hardness of the coat layer, the adhesion between the base plastic film and the hard coat layer, and various optical properties are excellent.

[0029]

According to the present invention, by treating the surface of a metal oxide ultrafine particle having a silicon oxide film with a coupling agent, the metal oxide ultrafine particle can be sufficiently bonded to a resin. Since it is positively applied, sufficient dispersibility in the resin is improved, and a coating film having high mechanical strength can be obtained even if the amount of the ultrafine metal oxide particles added to the resin is increased.

Moreover, since the ultrafine metal oxide particles themselves are covered with the silicon oxide film, resistance to acid or alkali is generated, and the adhesion between the resin and the ultrafine metal oxide particles is improved. It is possible to prevent an acid or an alkali from penetrating into their interfaces, and to impart acid resistance and alkali resistance to the metal oxide ultrafine particles.

Further, even if the amount of the ultrafine metal oxide particles added to the hard coat layer is increased, the strength of the cured coating film of the hard coat layer can be maintained high.

Further, since the refractive index of the hard coat layer can be adjusted by adjusting the increase / decrease in the amount of the ultrafine metal oxide particles added to the hard coat layer, it is easy to prevent the occurrence of interference fringes. You can do it.

Further, the energy of the coating film surface of the obtained hard coat layer is lowered, and the wettability and the adhesiveness are improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a layer structure of an antireflection film obtained in Example 1.

[Explanation of symbols]

 1 Base Plastic Film 2 Hard Coat Layer 3 Antireflection Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B29D 11/00 2126-4F C08J 7/06 CFD Z // C08L 67:00 (72) Inventor Yoshihara Toshio 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd. (72) Inventor Natsuko Yamashita 1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo (72) Inventor Yuko Suzuki 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Motohiro Oka 1-1-1 Ichigaya-kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd.

Claims (5)

[Claims] (1) A metal oxide ultrafine particle having a bondability with a resin is obtained by forming a silicon oxide film on the metal oxide ultrafine particle and further treating the surface with a coupling agent. 2) The metal oxide ultrafine particles are dispersed in an ionizing radiation curable resin, and (3) the obtained metal oxide ultrafine particle dispersed ionizing radiation curable resin is applied onto a base plastic film. A method for producing a plastic film for an optical material having a hard coat layer for preventing the generation of interference fringes. 2. The metal oxide is Sb ₂ O ₅ , TiO
₂ , Y ₂ O ₃ , ZrO ₂ , SnO ₂ , ITO (indium-tin oxide), La ₂ O ₃ , metal oxide ultrafine particles of Al ₂ O ₃ and ultrafine particles composed of a solid solution of SnO ₂ and WO _3. The method for producing a plastic film for an optical material having a hard coat layer for preventing generation of interference fringes according to claim 1, which is one kind or two or more kinds. 3. The method for producing a plastic film for an optical material having a hard coat layer for preventing the generation of interference fringes according to claim 1, wherein the base plastic film is a polyethylene terephthalate film. 4. A plastic film for an optical material obtained by the method for producing a plastic film for an optical material having a hard coat layer for preventing the generation of interference fringes according to claim 1. 5. An antireflection film, comprising an antireflection layer laminated on the plastic film for an optical material according to claim 4.