JPH10110118A - Antifouling hard coat agent and optical recording media - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hard coat agent capable of improving antifouling properties of the surface of an optical recording media by forming an antifouling hard coat layer on a surface of the optical recording media by including non- cross-linking type fluorine-based surfactant. SOLUTION: This hard coat agent includes 0.001-3wt.%, preferably 0.1-1wt.% non-cross-linking type fluorine-based surfactant. The non-cross-linking type fluorine-based surfactant is preferably a fluorinated alkyl ester and the fluorinated alkyl ester is represented by a compound of the formula [(a) to (d) are each 0-15; R is H or an alkyl]. The objective hard coat agent is obtained by compounding a photocurable resin as a base. A mixed system of 20-80wt.% urethane acrylate and/or 611 epoxy acrylate, with 80-20wt.% monofunctional and/or polyfunctional acrylate is preferably used. Preferably, good fouling properties are obtained when a contact angle of both artificial perspiration and squalene to the hard coat layer is >=90 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium provided with an antifouling hard coat layer containing a non-crosslinking type fluorine-containing surfactant.

[0002]

2. Description of the Related Art Optical disks are large in capacity and excellent in portability, and are being put to practical use. Each of these optical discs has a structure in which a recording layer is formed on a transparent substrate, and a protective resin layer is further laminated on the recording layer to protect the recording layer. The transparent substrate side opposite to the recording layer Recording and / or reproduction of information is performed by injecting a laser beam from the.

[0003] Substrates to be used include glass, polycarbonate, polymethyl methacrylate and the like, but polycarbonate is often used in view of workability, handleability, price and the like. However, this polycarbonate is soft, and is easily charged with static electricity due to friction with air generated by rotation in the drive. For this reason, the polycarbonate substrate is liable to be contaminated with air and easily scratched. While adhering dirt are manifold, SiO ₂ in the air as a _{typical, Fe 2 O 3, Al 2} O 3
There are inorganic substances such as and organic substances such as human sweat and fingerprints,
Its dimensions are also distributed from several hundred μm to 0.01 μm. The type of dirt and the degree of dirt greatly differ depending on the use environment. Among these stains, SiO ₂ , Fe ₂ O
_3. Inorganic substances such as Al ₂ O ₃ can be relatively easily cleaned by air blow, for example. On the other hand, oil components (organic substances) such as human sweat and fingerprints, unlike inorganic substances, are not easily removed by air blow alone. For this reason, there is a method of removing the dirt using a cleaner dedicated to an optical disk. However, in any case, when information is recorded and / or reproduced in a state where dirt adheres to the surface of the optical recording medium or the substrate is scratched due to the dirt, the laser light is scattered and a signal error occurs. As a result, accurate information recording and / or reproduction cannot be performed. It is known that a hard coat layer is usually provided for the purpose of protecting the surface of the polycarbonate substrate in order to prevent these. It is also known that the hard coat layer itself is given an antistatic property in order to make it difficult for dust and dirt to adhere thereto. For example, JP-A-60-239946 and JP-A-61-2
No. 76145 discloses that a cationic amine is added as an antistatic agent, an anionic alkylbenzene sulfonate, a nonionic polyol, an ethylene oxide of an alkylphenol, and an amphoteric imidazoline-type or alanine-type metal salt are added. In JP-A-3-49053, an aliphatic dimethylethylammonium ethosulfate compound is added. In JP-A-3-173949, a lauryl compound is added. In JP-A-4-80267, an anionic compound having a thiocyanic acid and an alkylene glycol chain is added. There is a method of adding a surfactant. All of these surfactants have an effect of making it difficult to adhere inorganic dirt such as dust and dirt. However, these hard coat agents containing an antistatic agent have almost no effect on stain resistance to organic stains such as human sweat and fingerprint marks. Nevertheless, the reason why this has not been considered a problem so far is that many rewritable optical disks are contained in a cartridge, and the surface of the optical disk is rarely directly touched with a hand. In addition, even if it becomes dirty, the problem has been solved by wiping off the dirt using a cleaner or the like dedicated to an optical disk. However, in the future, rewritable optical disks may be used naked without using a cartridge, and it is expected that the chance of contaminating the disk surface with human sweat or fingerprint marks will increase more than before. . Furthermore, in the case of an optical disk for high-density recording, for example, a DVD, since the laser beam spot diameter is small, even a small dirt is highly likely to cause a signal error. In this case, of course, it is possible to wipe off dirt using a cleaner, but not only does the work required for wiping off the dirt increase, but also the hard coat layer itself is damaged or the hard coat layer itself is damaged. Can be worn and worn away.

[0004]

SUMMARY OF THE INVENTION The present invention provides an optical recording medium in which the antifouling property of the surface of the optical recording medium is significantly improved by providing an antifouling hard coat layer on the surface of the optical recording medium. .

[0005]

Means for Solving the Problems To solve the above problems, the present invention provides a non-crosslinked fluorine-based surfactant in an amount of from 0.01 to 0.01%.
An antifouling hard coat agent for optical recording media characterized by containing 3% by weight.

Further, the present invention comprises an optical recording medium characterized in that a hard coat layer containing 0.01 to 3% by weight of a non-crosslinking type fluorine-containing surfactant is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, it is found that the antifouling property of the optical recording medium surface can be remarkably improved by providing an antifouling hard coat layer containing a non-crosslinking type fluorine-containing surfactant on the surface of the optical recording medium. I started.

In the present invention, the target dirt is mainly human sweat or fingerprint marks, and antifouling means that these dirt does not adhere or hardly adheres.

The present invention relates to an antifouling hard coat agent containing a non-crosslinking type fluorine-containing surfactant and an optical recording medium having an antifouling hard coat layer. The optical information recording medium refers to an optical disk, an optical card, an optical tape, or the like that can record, erase, and reproduce information by irradiating light.
These optical information recording media include a read-only (ROM) optical recording medium, a rewritable (RAM) optical recording medium such as a magneto-optical recording medium and a phase-change optical recording medium, a partial read-only (PROM) optical recording medium, and a write-once type. (WO) There is an optical recording medium and the like, but an optical disk, such as a CD-ROM, which is used in a naked state without using a cartridge, has a higher recording density than a conventional optical recording medium. An optical recording medium in which the beam spot diameter is considerably small and a signal error is liable to occur even for smaller dirt, for example, DV.
It is particularly effective for things like D.

In the present invention, the method of providing the antifouling hard coat layer is not particularly limited. For example, a method of dissolving or kneading a non-crosslinkable fluorine-based surfactant in a cured resin as a base, coating and curing. Are used. In addition, a hard coat layer containing no non-crosslinking type fluorine-containing surfactant may be applied, and the above-mentioned antifouling hard coat layer may be further provided. As a coating method, a spin coating method, a dip coating method, a spray coating method, a roll coating method, or the like can be used.

Examples of the base cured resin include compounds having at least one crosslinkable double bond in one molecule. For example, a photo-curable resin, a thermo-curable resin, an anaerobic-curable resin, a commonly used curable resin, or the like can be used.

As the photo-curable resin, there are acrylic resins such as polyurethane acrylate, epoxy acrylate and polyol acrylate. Specifically, it comprises the following compositions (1) to (4).

(1) Crosslinkable oligomer (2) Monofunctional and polyfunctional monomers (3) Photopolymerization initiator (4) Photoinitiator Auxiliary (1) Polyester (meth) acrylate, polyether (meth) acrylate, polyurethane (Meta)
Acrylate, epoxy (meth) acrylate, silicone (meth) acrylate, and the like can be given. Specific examples include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bisphenol A type epoxy acrylate, polyurethane diacrylate, and cresol novolak type epoxy (meth) acrylate. (2) as bifunctional or 3
Functional, tetrafunctional, and hexafunctional (meth) acrylates and the like can be mentioned. Specifically, the bifunctional (meth) acrylate is tripropylene glycol di (meth)
There are acrylate, 1,6-hexanediol diacrylate, tetraethylene glycol di (meth) acrylate and the like. Trifunctional (meth) acrylates include trimethylolpropane tri (meth) acrylate,
And pentaerythritol tri (meth) acrylate. Examples of the tetrafunctional (meth) acrylate include tetramethylolmethanetetra (meth) acrylate and pentaerythritoltetra (meth) acrylate. Hexafunctional (meth) acrylates include dipentaerythritol hexaacrylate.
Examples of (3) include ketone-based, benzoin-based, and thioxane-based photopolymerization initiators. Specifically, ketones include acetophenone and benzophenone. Benzoin includes benzoin, benzoin methyl ether and the like. Examples of the thioxane include thioxane and 2-methylthioxane. Examples of (4) include photoinitiating aids such as n-butylamine, triethylamine and allylthiourea.

Of these, urethane acrylate and / or epoxy acrylate 20 to 80 are particularly preferred.
% By weight, monofunctional and / or polyfunctional acrylate 80
-20% by weight of a mixed system.

The light used to cure these photocurable resins is ultraviolet light, electron beam, gamma ray, or the like.
In the case of an electron beam or a gamma ray, the above (3) is not necessarily required.
It is not necessary to contain (4). As these radiation sources, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an accelerating electron, and the like can be used.

The fluorine-based surfactant has no polymerizable double bond and does not crosslink with the base resin, that is, a non-crosslinkable type and a crosslinkable type which has a polymerizable double bond and crosslinks with the base resin. There is. Non-crosslinkable fluorine surfactants such as fluorinated alkyl esters, perfluoroalkyl alkoxylates, perfluoroalkyl sulfonates,
Perfluoroalkyl carboxylate, perfluoroalkyl ammonium salt and the like. Examples of the non-crosslinkable fluorine-based surfactant include a so-called fluorine-based (meth) acrylate and a fluorine-based epoxy acrylate in which a hydrogen atom of (meth) acrylate is replaced with a fluorine atom. Of these, the non-crosslinkable fluorine-based surfactant does not crosslink with the base resin, and thus tends to aggregate on the surface of the coating layer during curing. Therefore, the antifouling effect is exhibited only by adding a small amount. On the other hand, in the case of a fluorine-based (meth) acrylate or a fluorine-based epoxy acrylate of a crosslinkable fluorine-based surfactant, in order to crosslink with a base resin,
Unlike the case of a non-crosslinking fluorine-based surfactant, it does not aggregate on the surface of the coating layer during curing. Therefore, it is necessary to add a considerable amount of a fluorine (meth) acrylate or a fluorine-based epoxy acrylate in order to produce the same level of antifouling effect as a non-crosslinked fluorine-based surfactant. However, in this case, since the ratio of the base resin to the whole decreases, there is a concern that the original characteristics of the base resin may be deteriorated. For example, there is a change in viscosity or a decrease in surface hardness. For this reason, a non-crosslinked fluorine-based surfactant that exhibits sufficient antifouling properties without affecting the original properties of the base resin is preferable. Among them, fluorinated alkyl esters are particularly excellent in the antifouling effect. For example, those having the following structural formula can be mentioned.

[0017]

Embedded image Here, a is an integer of 0 to 15, b, c and d are 0 to 15
Is an integer. R is hydrogen or an alkyl group such as a methyl group and an ethyl group.

Examples of such a fluorinated alkyl ester include, for example, "Fluorad FC" manufactured by Sumitomo 3M Limited.
-430 ".

When the concentration of the non-crosslinked fluorine-based surfactant is very low, the antifouling effect is not sufficiently exhibited. When the concentration is high, the viscosity increases, and not only the film thickness control becomes difficult, but also the surface hardness decreases. Therefore, it is easy to be damaged. For these reasons, the amount of addition of the non-crosslinkable fluorine-based surfactant is 0.01
-3% by weight is preferred, more preferably 0.1-
1% by weight is good.

The antifouling property of the hard coat layer can be evaluated by measuring the contact angle of a contaminant with the hard coat layer. A large contact angle indicates that the antifouling property is excellent. Particularly, when the contact angle is 90 ° or more, good antifouling property can be obtained. The contaminants are mainly human sweat and fingerprint marks, and at the time of measurement, artificial sweat can be used as a measurement liquid as a substitute for them. It is also preferable to use organic squalene which is a main component of sweat and fingerprint marks. More preferably, if the contact angle of both artificial sweat and squalene is 90 ° or more, good antifouling properties can be obtained.

[0021]

EXAMPLES The present invention will be described below with reference to examples. However, the present invention is not limited by the following examples.

The evaluation of the antifouling property is as follows: (1) Measurement of contact angle,
(2) The artificial fingerprint liquid was press-bonded using a pseudo fingerprint, and two types of wiping properties after wiping were performed. The contact angle is measured by the contact angle meter "FACE CONTACT-" of Kyowa Interface Science Co., Ltd.
ANGLEMETER "at a static contact angle (hereinafter simply referred to as a contact angle). The measurement target liquid was artificial sweat and organic components of oleic acid, squalene and triolein, which are the main components of sweat and fingerprint marks. A visual evaluation after wiping the artificial fingerprint liquid was performed by applying an artificial fingerprint liquid to a pseudo fingerprint (made of silicon) and attaching the artificial fingerprint liquid at a load of ² kg / cm ² , followed by “Kimwipe Wiper S-2000” (Jujo Kimberly Co., Ltd.). )) Was wiped three times to evaluate the wiping property of the artificial fingerprint liquid.

：: Artificial fingerprint mark is not visible Δ: Part of the artificial fingerprint mark remains ×: Artificial fingerprint mark remains almost The components of the artificial sweat and artificial fingerprint liquid used are as follows.

Components of artificial sweat (per liter of water) L-histidine HCl.H ₂ O 0.5 g NaCl 5.0 g Disodium phosphate 12H ₂ O 5.0 g 1 / 10N NaOH 25.0 ml Components of artificial fingerprint liquid ( Water: ethanol = 1: 1 (volume ratio)
NaCl 7.0 g Urea 1.0 g Lactic acid (85%) 4.0 g The surface hardness of the hard coat layer was measured using a surface property measuring device "Tribogear TYPE: HEIDON-14DR" (Shinto Scientific Co., Ltd.) This was performed using Measurement conditions are JIS K5
Performed according to 400-1990. The conditions are shown below.

Moving speed: 0.5 mm / sec (30 mm / min) Number of measurements: 5 Load: 1.00 ± 0.05 kg Pencil: “Mitsubishi Uni”

(Example 1) UV-curable hard coat agent ("urethane acrylate" 50% by weight, polyfunctional acrylate 48% by weight, photopolymerization initiator "Irgacure 1")
84 "(2% by weight) as a non-crosslinkable fluorosurfactant" FLORARD FC-430 "manufactured by Sumitomo 3M Limited.
Was added and stirred thoroughly. This was applied to a thickness of 6 μm by spin coating on the opposite side of the recording layer forming surface of the polycarbonate substrate for optical disks (diameter 120 mm, thickness 0.6 mm). After that, 700mJ / cm
^The hard coat layer was cured by irradiating the ultraviolet light of No. ² and the contact angle of the surface was measured. The contact angle of each solvent was as follows.

[0027] The wiping property and pencil hardness of the artificial fingerprint liquid were as follows. Wipeability of artificial fingerprint liquid ○ Pencil hardness HB

(Comparative Example 1) A hard coat agent was spin-coated and cured in the same manner as in Example 1 except that the non-crosslinkable fluorine-based surfactant was not added, and the contact angle was measured.

[0029]

Comparative Example 2 Example 1 was repeated except that 10% by weight of a cross-linkable fluorine-based surfactant 2- (perfluorooctyl) ethyl methacrylate was added instead of the non-cross-linked fluorine-based surfactant. Similarly, the contact angle was measured.

[0031]

Comparative Example 3 The procedure of Example 1 was repeated, except that 0.6% by weight of an antistatic agent alkylbenzene sulfonate was added instead of the non-crosslinkable fluorosurfactant.
The contact angle was measured.

[0033]

[0034]

By providing an antifouling hard coat layer containing a non-crosslinking type fluorine-containing surfactant on the surface of the optical recording medium, the antifouling property against human sweat and fingerprint marks is improved.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08K 5/10 C08K 5/10 5/19 5/19 5/42 5/42 C08L 33/04 C08L 33/04 63/10 63 / 10 75/14 75/14

Claims (13)

[Claims] 1. The method according to claim 1, wherein the non-crosslinking type fluorine-containing surfactant is 0.01%.
An antifouling hard coat agent for an optical recording medium, wherein the hard coat agent is contained in an amount of 3 to 3% by weight. 2. The at least one non-crosslinked fluorine surfactant selected from fluorinated alkyl esters, perfluoroalkyl alkoxylates, perfluoroalkyl sulfonates, perfluoroalkyl carboxylate salts, and perfluoroalkyl ammonium salts. The antifouling hard coat agent for an optical recording medium according to claim 1, comprising: 3. The antifouling hard coat agent for optical recording media according to claim 1, wherein the non-crosslinkable fluorine-based surfactant is a fluorinated alkyl ester. 4. The antifouling hard coat agent for an optical recording medium according to claim 1, comprising a non-crosslinkable fluorine-based surfactant and a photocurable resin. 5. The photocurable resin is an acrylic oligomer 20.
80% by weight and 80-20% by weight of acrylic monomer
The antifouling hard coat agent for an optical recording medium according to claim 4, comprising: 6. The antifouling property for an optical recording medium according to claim 5, wherein the acrylic oligomer is urethane acrylate and / or epoxy acrylate, and the acrylic monomer is monofunctional and / or polyfunctional acrylate. Hard coat agent. 7. A non-crosslinked type fluorine-containing surfactant having a concentration of 0.01
An optical recording medium comprising a hard coat layer containing up to 3% by weight. 8. The non-crosslinkable fluorine-based surfactant is at least one selected from a fluorinated alkyl ester, a perfluoroalkyl alkoxylate, a perfluoroalkyl sulfonate, a perfluoroalkyl carboxylate, and a perfluoroalkyl ammonium salt. The optical recording medium according to claim 7, comprising: 9. The optical recording medium according to claim 7, wherein the non-crosslinkable fluorinated surfactant is a fluorinated alkyl ester. 10. The optical recording medium according to claim 7, wherein the hard coat layer is made of an acrylic resin. 11. The optical recording medium according to claim 7, wherein the contact angle of artificial sweat to the hard coat layer is 90 ° or more. 12. The optical recording medium according to claim 7, wherein a contact angle of squalene to the hard coat layer is 90 ° or more. 13. The optical recording medium according to claim 7, wherein the contact angle of artificial sweat and squalene to the hard coat layer is 90 ° or more.