WO2011007571A1 - Ultraviolet-curable resin composition for use in optical disks and cured products thereof - Google Patents

Abstract

An ultraviolet-curable resin composition characterized by comprising (A) a (meth)acrylate having an aliphatic chain, particularly a C10-25 aliphatic chain, either (B) a (meth)acrylate monomer exclusive of the (meth)acrylate (A) and the following (meth)acrylate (C) and/or (C) a urethane (meth)acrylate, and (D) a photopolymerization initiator. The ultraviolet-curable resin composition is suitable for use in the intermediate resin layer of a multilayer optical disk, and ensures high mass productivity in the formation of substrates by the 2P method. Further, the ultraviolet-curable resin composition exhibits excellent peelability from a stamper, and can provide an optical disk base which exhibits a reduced change of warpage when curing or after the resulting multilayer disk is placed under high-temperature and high-humidity conditions.

Description

Ultraviolet curable resin composition for optical disc and cured product thereof

The present invention relates to an ultraviolet curable resin composition, a use of the composition for a multilayer optical disk (especially for an intermediate resin layer), and an optical disk having a cured layer of the resin composition, in particular, a polycarbonate stamper (for an optical disk). The present invention relates to a resin composition for efficiently producing next-generation high-density multilayer optical discs that have high releasability from molds and have small warpage during curing and low warpage under high temperature and high humidity.

In recent years, the capacity of optical discs has increased significantly, and multilayer type optical discs are rapidly spreading in order to increase the storage capacity. Technologies for increasing the recording capacity of optical disks include shortening the recording / reproducing beam, increasing the NA (numerical aperture) of the objective lens in the recording / reproducing beam irradiation optical system, and increasing the number of recording layers. It is done. Among these, the increase in capacity by increasing the number of recording layers can increase the capacity at a lower cost than the reduction in wavelength and the increase in NA.
For example, a DVD disk having two recording layers has a structure in which two recording layers are laminated via a transparent resin intermediate layer (hereinafter also referred to as an intermediate resin layer). Specifically, a 0.6 mm first transparent resin substrate, a first recording layer, a first translucent reflective film layer, an adhesive layer, a transparent resin intermediate layer, a second recording layer, and a second reflective film This is a structure in which a layer, an adhesive layer, and a 0.6 mm second transparent resin substrate are laminated in this order. As a method for forming the transparent resin intermediate layer in this case, for example, an ultraviolet curable resin composition for forming the transparent resin intermediate layer is placed on the adhesive layer formed on the first translucent reflective film layer. A transparent resin stamper with a concave and convex pattern such as a guide groove for recording / reproducing beam is placed thereon and spin-coated. After the formed UV curable resin composition layer is cured, the stamper is peeled off, A method of forming a transparent resin intermediate layer by transferring irregularities on the surface of the ultraviolet curable resin composition, or forming a cured product layer of the resin composition on a stamper, and then a first translucent reflective film layer The stamper with the cured product layer is placed on the adhesive layer forming resin placed thereon, and after the adhesive layer is formed by spin coating, the adhesive layer is cured, and then the stamper is cured of the resin composition. Peel from the physical layer and remove the transparent resin intermediate layer How to formation and the like (transfer method).

In a Blu-ray disc, in a read-only disc, a pit-like recording pattern is transferred to one side of a polycarbonate substrate having a diameter of 120 mm and a thickness of 1.1 mm, for example, and a first recording layer is formed on the surface of the substrate. The reflective film layer, for example, a silver alloy reflective film layer is formed. Further, a transparent resin intermediate layer having a pit-like recording pattern transferred thereon is formed on the first reflective film layer via an adhesive layer, and the second recording layer and the second recording layer are formed on the transparent resin intermediate layer (intermediate film). A second reflective film layer, for example, a silver alloy reflective film layer is formed. A transparent resin layer is laminated on the reflective film layer. In addition, the technique with which a silver alloy reflective film layer is formed into a film in vacuum, for example by sputtering method is proposed.
In a recording disk, for example, a first reflective film layer, a first dielectric layer, and a first recording layer are formed on the surface of a substrate on which a pit-like recording pattern is transferred on one side of a polycarbonate substrate having a diameter of 120 mm and a thickness of 1.1 mm. A layer, a second dielectric layer, and a transparent resin intermediate layer, a second reflective film layer, a third dielectric layer, a second dielectric layer, and an adhesive layer on the second dielectric layer. 2 recording layers, a fourth dielectric layer, and a transparent resin layer in this order.
In these cases, an ultraviolet curable resin composition for forming a transparent resin intermediate layer is applied on the reflective film layer or dielectric layer via an adhesive layer, and guide grooves for recording / reproducing beams, etc. This is formed by pressing a transparent resin stamper with a concave / convex pattern and curing the ultraviolet curable resin composition, then peeling the stamper and transferring the irregularities onto the surface of the ultraviolet curable resin composition (transfer method) .
Here, the transparent resin intermediate layer usually has a second reflective film layer formed on the uneven surface of a read-only disk, and the opposite surface is bonded to the first reflective film layer via an adhesive layer. ing. In the recording disk, the transparent resin intermediate layer has a second reflective film layer formed on the uneven surface, and the opposite surface is bonded to the second dielectric layer via the adhesive layer. .

Generally, this transfer method is called a 2P (Photo Polymerization) method, and the ultraviolet curable resin composition used is called a 2P agent.
Examples of the transparent resin for the transparent resin stamper include acrylic resins, methacrylic resins, polycarbonate resins, polyolefin resins (particularly amorphous polyolefins), polyester resins, polystyrene resins, and epoxy resins. Among these, amorphous polyolefin is preferable from the viewpoint of peelability after curing the 2P agent, low hygroscopicity, shape stability, and the like, and polycarbonate resin is preferable from the viewpoint of material cost. Therefore, for the purpose of reducing costs, a method for manufacturing an optical recording medium (multilayer optical recording medium) having a plurality of recording layers, which can be peeled even by an inexpensive polycarbonate stamper and has improved yield, has been proposed. Resins suitable for the method have also been developed (Patent Document 1).

At present, the mainstream of ultraviolet curable resin compositions when using the 2P method is, for example, (a) a composition containing a prepolymer capable of photoradical polymerization, a monomer and a photopolymerization initiator, and (b) photocationic polymerization. Examples thereof include a composition containing a possible prepolymer, a monomer, and a photopolymerization initiator, and (c) a composition in which a radical photopolymerizable composition and a cationic polymerizable composition are mixed.

As prepolymers, various types of epoxy (meth) acrylate (epoxy skeleton added with (meth) acryloyl group) or / and urethane (meth) acrylate (urethane skeleton added with (meth) acryloyl group) Etc.). Each of these components has a significant influence on the required characteristics of the optical disc, such as moldability such as releasability from a stamper, adhesion to a reflective film layer or dielectric layer, moisture resistance, and flexibility.

As the monomer, a monomer having a (meth) acryloyl group as a functional group is generally used. Those having a vinyl group are also used. Generally, a prepolymer has a high viscosity and is difficult to use as a 2P agent alone, and therefore a monomer is used as a reactive diluent. For example, by using a trifunctional or higher functional monomer, the crosslink density of the cured product is increased, and the hardness, Young's modulus, and heat and humidity resistance are improved.

When producing a multilayer optical disk, if the peelability from the transparent resin stamper is poor, a part of the transparent resin intermediate layer peels off together with the transparent resin stamper, resulting in a defect. If transferability is poor, an error occurs during recording / reproduction. If the warpage is large after UV curing, the recording layer and the reflective film layer cannot be uniformly formed on the formed concavo-convex pattern, the second substrate cannot be bonded in the case of DVD, or 0 in the case of Blu-ray Disc. A 1 mm light transmission layer cannot be formed uniformly. In addition, when the uneven pattern is deformed under high temperature and high humidity, the recording characteristics (for example, jitter characteristics) of the first and second recording layers are not equivalent.
In the 2P agent described in Patent Documents 2 to 5, an uneven pattern is formed on a layer formed on a glass substrate using a metal stamper. Patent Documents 6 to 10 also describe various 2P agents.

JP 2007-224057 A JP-A-5-59139 JP-A-5-132534 Japanese Patent Laid-Open No. 5-140254 JP-A-5-132506 JP 2003-331463 A JP 2004-288242 A JP 2004-288264 A JP 2005-332564 A Japanese Patent No. 4193916

Usually, an ultraviolet curable resin used as a 2P agent needs to be easily peeled off from the stamper (highly peelable from the stamper) while the concave / convex pattern is formed by the stamper while the pattern is held. At that time, if it is difficult to peel off from the stamper, the resin adheres to the stamper, resulting in a defect in the resin layer or an uneven pattern, which causes a problem in the formation of the reflective film or the dielectric layer and reduces the production efficiency. Will be invited. Even if the resin has high peelability from the stamper, there are problems such as reading error if the amount of change in warping is large when ultraviolet curing or when the multilayer disk is placed under high temperature and high humidity.

Therefore, in view of such circumstances, the object of the present invention is to use a (meth) acrylate having a fatty chain, in particular, a (meth) acrylate having a specific fatty chain, so that the release from the stamper, particularly from a polycarbonate stamper. To provide a resin composition that is excellent in peeling off and has a small amount of change in warping even when the formed resin layer is cured and after the multilayer disk having the cured product layer is placed under high temperature and high humidity. It is in.

Furthermore, since the resin composition of the present invention directly adheres to either the reflective film or the dielectric layer by curing, an adhesive layer is provided to adhere the cured resin layer to the reflective film or dielectric layer when the stamper is peeled off. After that, there is no need to peel off the stamper. That is, the stamper can be easily peeled off as it is by forming a resin layer directly on either the reflective film or the dielectric layer and forming irregularities and / or curing with the stamper. Therefore, it is possible to omit an adhesive layer for adhering the cured layer of the ultraviolet curable resin composition used as the 2P agent to the surface of the reflective film or the dielectric layer.

By using (meth) acrylate having a fatty chain, particularly (meth) acrylate having a specific fatty chain, the present inventors have improved the peelability from a stamper, particularly a polycarbonate stamper, and at the time of curing and a multilayer disk The resin composition was found to have a small amount of change in warping after being placed under high temperature and high humidity. This has led to the development of a UV-effect resin composition that is excellent in releasability from a polycarbonate stamper and has a small amount of change in warping even when cured and after the multilayer disk is placed under high temperature and high humidity.

The present invention relates to the following (1) to (12).
(1) It contains (A) (meth) acrylate having a fatty chain, (B) (meth) acrylate monomer and / or (C) urethane (meth) acrylate, and (D) a photopolymerization initiator. An ultraviolet curable resin composition for multilayer optical disks.
(2) (A) (meth) acrylate having a fatty chain is lauryl (meth) acrylate, stearyl (meth) acrylate, cetyl (meth) acrylate, behenyl (meth) acrylate, isolauryl (meth) acrylate, isostearyl (meth) The ultraviolet curable resin composition for multilayer optical disks according to (1), which is one or more selected from the group consisting of: acrylate, isocetyl (meth) acrylate, and isobehenyl (meth) acrylate.
(3) (B) (Meth) acrylate monomer is isobornyl (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, and hydroxypivalaldehyde modified trimethylol The ultraviolet curable resin composition for multilayer optical disks according to (1) or (2), which is one or more selected from the group consisting of propanedi (meth) acrylate.
(4) 5 to 90% by weight of component (A), 5 to 90% by weight of component (B) and / or (C), and 1 to 15% by weight of component (D) based on the entire resin composition The ultraviolet curable resin composition for multilayer optical disks according to any one of (1) to (3).
(5) An optical disc having a cured product obtained by irradiating the resin composition according to any one of (1) to (4) with ultraviolet rays.

式中、ＲはＨ又はＣＨ_３、ｎは１０～２５の整数を示す、
及び
（Ｂ）イソボルニル（メタ）アクリレート、プロピレンオキサイド変性ネオペンチルグリコールジ（メタ）アクリレート、トリシクロデカンジメチロールジ（メタ）アクリレート、及びヒドロキシピバルアルデヒド変性トリメチロールプロパンジ（メタ）アクリレートからなる群から選択される少なくとも一種の（メタ）アクリレートモノマー、又は
（Ｃ）有機ポリイソシアネートとヒドロキシ（メタ）アクリレート化合物との反応で得られるウレタン（メタ）アクリレート、
及び
（Ｄ）光重合開始剤、
を含有し、
樹脂組成物の総量に対して、
（ｉ）（Ａ）成分が５～９０重量％、
（ｉｉ）（Ｂ）成分又は（Ｃ）成分、又は、（Ｂ）及び（Ｃ）の両者が５～９０重量％であり、（Ａ）～（Ｃ）成分の総量が８５～９９重量％であり、
（ｉｉｉ）（Ｄ）成分が１～１５重量％である、　
紫外線硬化型樹脂組成物。　　 (6) (A) (meth) acrylate having a fatty chain represented by the following formula (1),

In the formula, R represents H or CH ₃ , n represents an integer of 10 to 25,
And (B) isobornyl (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, and hydroxypivalaldehyde modified trimethylolpropane di (meth) acrylate At least one (meth) acrylate monomer selected from: or (C) urethane (meth) acrylate obtained by reaction of an organic polyisocyanate with a hydroxy (meth) acrylate compound,
And (D) a photopolymerization initiator,
Containing
For the total amount of the resin composition,
(I) 5 to 90% by weight of component (A),
(Ii) The component (B) or the component (C), or both (B) and (C) is 5 to 90% by weight, and the total amount of the components (A) to (C) is 85 to 99% by weight. Yes,
(Iii) The component (D) is 1 to 15% by weight,
UV curable resin composition.

(7) The ultraviolet curable resin composition according to (6), wherein the fatty chain of (meth) acrylate having a fatty chain is a fatty chain having a branched chain.
(8) The (meth) acrylate having a fatty chain is at least selected from the group consisting of isodecyl acrylate, isolauryl (meth) acrylate, isostearyl (meth) acrylate, isocetyl (meth) acrylate, and isobehenyl (meth) acrylate. The ultraviolet curable resin composition according to (7), which is a kind.
(9) The organic polyisocyanate is at least one diisocyanate selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, and diphenylmethane-4,4′-diisocyanate, or dicyclopentanyl isocyanate. The ultraviolet curable resin composition according to any one of (6) to (8) above.
(10) The ultraviolet curable resin composition according to any one of the above (6) to (9), wherein the hydroxy (meth) acrylate compound is a hydroxy-substituted C2 to C10 aliphatic (meth) acrylate.
(11) Use of the ultraviolet curable resin composition according to any one of (6) to (10) above for an intermediate resin layer of a multilayer disk.
(12) A multilayer disc having a cured product layer of the ultraviolet curable resin composition according to any one of (6) to (10) above.

The ultraviolet curable resin composition of the present invention and the cured product thereof are excellent in peeling from a stamper, particularly from a polycarbonate stamper (low peeling strength from the stamper), and change in warpage before and after curing during curing. It is useful as a 2P agent having a small amount and a small amount of change in warpage before and after the multilayer disk having the cured product layer is placed under high temperature and high humidity. Moreover, in the ultraviolet curable resin composition of the present invention, it is possible to omit the adhesive layer and form the intermediate resin layer with one liquid. In addition, the viscosity can be adjusted appropriately by the combination of the component (A) and the component (B) or / and the component (C), and the intermediate resin layer of the multilayer disk can be formed efficiently. It is.

The present invention provides (i) (A) (meth) acrylate having a fatty chain, (ii) (B) (meth) acrylate monomer and / or (C) urethane (meth) acrylate, and (iii) (D) light. The present invention relates to an ultraviolet curable resin composition for multilayer optical disks, which contains a polymerization initiator.
In the present invention, the term “(meth) acrylate” is used in the meaning of either one or both of acrylate and methacrylate, as is generally used.
In the present invention, “%” or “part” means “% by weight” or “part by weight” unless otherwise specified. Further, the ultraviolet curable resin composition of the present invention is also simply referred to as “resin composition of the present invention”.

（式中、ＲはＨ又はＣＨ_３、ｎは１０～２５の整数を示す。） In the resin composition of the present invention, (A) (meth) acrylate having a fatty chain is used as an essential component. The fatty chain of the (meth) acrylate having a fatty chain is preferably a C10 to C25 fatty chain, more preferably a C10—CnH _{2n + 1} (where n is an integer of 10 to 25) represented by the following formula (1): A C25 alkyl group is preferred. Therefore, (meth) acrylate represented by the following formula (1) is preferable as the (meth) acrylate having a fatty chain.
Formula (1)

(In the formula, R represents H or CH ₃ , and n represents an integer of 10 to 25.)

Specific examples include, for example, lauryl (meth) acrylate, stearyl (meth) acrylate, cetyl (meth) acrylate, behenyl (meth) acrylate, isolauryl (meth) acrylate, isostearyl (meth) acrylate, isocetyl (meth) acrylate, And isobehenyl (meth) acrylate.
The fatty chain of the (meth) acrylate having a fatty chain is preferably a branched chain rather than a straight chain in terms of ease of peeling from the stamper, and a (meth) acrylate having a branched fatty chain is preferred. More preferred is a (meth) acrylate having a C10 to C25 branched chain. Accordingly, among the above specific examples, isolauryl (meth) acrylate, isostearyl (meth) acrylate, isocetyl (meth) acrylate or isobehenyl (meth) acrylate is more preferable.
The content of the (A) acrylate having an aliphatic chain in the composition is about 5 to 90% by weight, preferably about 10 to 80% by weight, based on the total amount (total) of the resin composition. Since this content varies depending on the component (B) or (C) used in combination, it cannot be generally specified, but in some cases, it is preferably about 5 to 50% by weight, more preferably about 5 to 40% by weight, still more preferably. Is about 10 to 40% by weight, most preferably about 10 to 30% by weight.
(A) As a commercially available product, (Meth) acrylate having a fatty chain is, for example, Blenmer SA, Blemmer CA, Blemmer VA manufactured by NOF Chemical Co., Ltd .; Isostearyl acrylate manufactured by Shin-Nakamura Chemical Co., Ltd .; -A, light acrylate IM-A, and the like.

(B) (Meth) acrylate monomer is used in the resin composition of the present invention. The (meth) acrylate monomer to be used is a (meth) acrylate monomer other than the (A) component and the (C) component, and any known one can be used without particular limitation. Examples include tricyclodecane (meth) acrylate, benzyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) ) Acrylate, morpholine (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, hydroxypivalaldehyde modified trimethylolpropane di (meth) acrylate, hydroxypivalic acid And neopentyl glycol di (meth) acrylate.

In combination with the component (A), in order to improve releasability and the like, isobornyl acrylate, propylene oxide modified neopentyl glycol diacrylate, tricyclodecane dimethylol diacrylate, and hydroxypivalaldehyde as a (meth) acrylate monomer It is preferable to use at least one selected from the group consisting of modified trimethylolpropane diacrylate.
These can be used as the (A) component in combination with a (meth) acrylate having a branched fatty chain to provide the resin composition of the present invention having low peel strength and little change in warpage. Among these, isobornyl (meth) acrylate and / or hydroxypivalaldehyde-modified trimethylolpropane diacrylate is more preferable, and a combination of both is more preferable.

The (C) urethane (meth) acrylate used in the resin composition of the present invention is used in place of the component (B), and includes (A) component and (C) component as the resin component. Although it can also be set as the resin composition which does not contain, this (C) component is normally used together with (B) component.
As urethane (meth) acrylate of (C) component, the compound obtained by making an organic polyisocyanate compound and a hydroxy (meth) acrylate compound react is preferable.
Examples of the organic polyisocyanate include diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, and isocyanates such as dicyclopentanyl isocyanate.
Among these, isophorone diisocyanate or tolylene diisocyanate is more preferable.
Examples of the hydroxy (meth) acrylate compound include hydroxy-substituted C2-C10 aliphatic (meth) acrylate and hydroxycaprolactone (meth) acrylate. Hydroxy-substituted C2-C10 aliphatic (meth) acrylates are preferred, specifically hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, dimethylol cyclohexyl mono (meth) acrylate, Examples include pentaerythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate.
Among these, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, pentaerythritol tri (meth) acrylate and the like are more preferable.
Accordingly, preferred urethane (meth) acrylates include urethane (meth) acrylates obtained by reaction of the organic polyisocyanate with the hydroxy-substituted C2-C10 aliphatic (meth) acrylate or hydroxycaprolactone (meth) acrylate. it can. Further, as a more preferable urethane (meth) acrylate, urethane (obtained by a reaction of isophorone diisocyanate or tolylene diisocyanate listed as the preferable organic polyisocyanate with a compound exemplified as a preferable hydroxy (meth) acrylate ( Mention may be made of (meth) acrylates.
The reaction is carried out as follows. That is, the organic polyisocyanate is mixed with 1.0 of its isocyanate group, and the hydroxy (meth) acrylate compound is mixed so that its hydroxyl group is preferably 1.0 to 2.1 equivalents, and reacted at 70 to 90 ° C. A urethane (meth) acrylate can be obtained.
The urethane (meth) acrylates can be used alone or in combination of two or more.

The content of at least one of (B) (meth) acrylate monomer or (C) urethane (meth) acrylate in the resin composition of the present invention is 5 to 5 in terms of the ratio (weight) to the total amount of the resin composition. About 90%, preferably about 10 to 80%. Further, the preferable range is 50 to 90% depending on the case, and more preferably 60 to 85%.
Further, the content ratio of the total amount of the components (A) to (C) with respect to the total amount of the resin composition of the present invention may be any as long as the effect of the present invention is achieved. In general, considering the viscosity of the resin composition, the peelability of the cured product layer from the stamper, the light transmittance of the cured product layer, the warp and durability of the optical disk having the cured product layer, the total amount of the resin composition On the other hand, the total amount of the components (A) to (C) is preferably contained at least 50%, more preferably at least 70%. More preferably, the total amount of components (A) to (C) is 85 to 99%, most preferably 90 to 99%, based on the total amount of the resin composition.
In the above case, the ratio of the component (A) to the other components (components (B) and (C)) is 1 part of the component (A), and other components (component (B) or component (C) Or the total amount of both when (B) and (C) are included) is usually about 1 to 20 parts, preferably about 2 to 10 parts, more preferably about 3 to 7 parts. .
The component (B) or the component (C) usually has no problem as long as at least one of them is contained in the resin composition. Therefore, either one may be 100% and the other may be 0% with respect to the total amount of both components. Usually, the component (B) is 30 to 100%, more preferably 50 to 100%, still more preferably 70 to 100%, and the component (C) is preferably 0 to 70% based on the total amount of both components. More preferably, it is 0 to 50%, and still more preferably 0 to 30%.

In the present invention, an epoxy (meth) acrylate can be appropriately contained as necessary. The epoxy (meth) acrylate is preferably obtained by reacting an epoxy resin having two or more epoxy groups in the molecule with a monocarboxylic acid compound (preferably (meth) acrylic acid) having an ethylenically unsaturated group. Can be mentioned. The raw material epoxy resin includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3- Bisphenol type epoxy compound such as epoxy compound of hexafluoropropane, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol S type epoxy resin, hydrogenated 2,2-bis (4-hydroxyphenyl) 1,1,1,3,3,3-Hexafluoropropane epoxy compounds such as hydrogenated bisphenol type epoxy compounds, brominated bisphenol A type epoxy resins, brominated bisphenol F type epoxy resins and the like halogenated bisphenol type epoxies Compound, EO / PO modified Aliphatic compounds such as phenol type epoxy resin, cycloaliphatic diglycidyl ether compound such as cyclohexanedimethanol diglycidyl ether compound, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, diethylene glycol diglycidyl ether Examples thereof include polysulfide type diglycidyl ether compounds such as diglycidyl ether compounds and polysulfide diglycidyl ethers, biphenol type epoxy resins, and polyether type epoxy resins.

Commercially available products of these epoxy compounds include, for example, jER828, jER1001, jER1002, jER1003, jER1004 (all manufactured by Japan Epoxy Resin), Epomic ^RTM R-140, Epomic ^RTM R-301, and Epomic R-304 (all Mitsui Chemicals, Inc.) DER-331, DER-332, DER-324 (all manufactured by Dow Chemical Co., Ltd.), Epicron 840, Epicron 850 (all manufactured by Dainippon Ink Co., Ltd.) UVR-6410 (manufactured by Union Carbide Corporation) ), Bisphenol-A type epoxy resin such as YD-8125 (manufactured by Toto Kasei Co., Ltd.), UVR-6490 (manufactured by Union Carbide Co., Ltd.), YDF-2001, YDF-2004, YDF-8170 (all of which are Toto Kasei Co. Bisphenol-F type epoxy resin, HBPA-DGE (manufactured by Maruzen Petrochemical Co., Ltd.), Rica Resin HBE-100 (Shin Nippon Rika Co., Ltd.) Hydrogenated bisphenol-A type epoxy resin such as DER-513, DER-514, DER-542 (all manufactured by Dow Chemical Co., Ltd.), Epolite 3002 (Kyoeisha Chemical) Fats such as PO-modified bisphenol-A type epoxy resin such as Celecide 2021 (manufactured by Daicel Corporation), Rica Resin DME-100 (manufactured by Shin Nippon Chemical Co., Ltd.), EX-216 (manufactured by Nagase Kasei Co., Ltd.) Cyclic epoxy resin, ED-503 (Asahi Denka Co., Ltd.), Rica Resin W Aliphatic diglycidyl ether compounds such as -100 (manufactured by Nippon Nippon Chemical Co., Ltd.), EX-212, EX-214, EX-850 (all manufactured by Nagase Chemical Co., Ltd.), FLEP-50, FLEP-60 (all Polysulfide type diglycidyl ether compound such as Toraythiocol Co., Ltd., biphenol type epoxy compound such as YX-4000 (Japan Epoxy Resin Co., Ltd.), Epolite ^RTM 100E, Epolite ^RTM 200P (all manufactured by Kyoeisha Chemical Co., Ltd.), etc. These polyether type epoxy compounds are mentioned.
The superscript RTM indicates a registered trademark (the same applies hereinafter).

Examples of the (D) photopolymerization initiator contained in the resin composition of the present invention include 1-hydroxycyclohexyl phenyl ketone (Irgacure ^RTM 184; manufactured by Ciba Specialty Chemicals), 1- [4- (2-hydroxy Ethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (Irgacure ^RTM 2959; manufactured by Ciba Specialty Chemicals), 2-hydroxy-1- {4- [4- (2 -Hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (Irgacure ^RTM 127; manufactured by Ciba Specialty Chemicals), 2,2-dimethoxy-2-phenylacetophenone (Irgacure ^RTM 651; Ciba Specialty Chemicals Co., Ltd. , Oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] (Esacure ONE; manufactured by Lamberti Co., Ltd.), 2-hydroxy-2-methyl-1-phenyl -Propan-1-one (Darocur ^RTM 1173; manufactured by Ciba Specialty Chemicals), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure ^RTM 907; Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone , Isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphe Le phosphine oxide (Lucirin TPO: manufactured by BASF Corporation), bis (2,4,6-trimethylbenzoyl) - phenyl phosphine oxide (IRGACURE ^RTM 819; manufactured by Ciba Specialty Chemicals Inc.), bis (2,6 And dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.

These photopolymerization initiators may be used alone or in combination at any ratio, and may be used in combination with photopolymerization initiation assistants such as amines.
The content of the photopolymerization initiator (D) in the resin composition of the present invention is 1 to 15% by weight, preferably about 3 to 10% by weight.
Examples of photopolymerization initiation assistants such as amines that can be used in the present invention include diethanolamine, 2-dimethylaminoethylbenzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester. Etc.
The content of the photopolymerization initiation assistant in the resin composition of the present invention is about 0 to 5%, more preferably about 0 to 3%. When a photopolymerization initiation assistant is used in combination, it is preferably 0.05 to 5% by weight, particularly preferably about 0.1 to 3% by weight. Usually, it is not necessary to use a photopolymerization initiation assistant in combination.

In the resin composition of the present invention, phosphoric acid (meth) acrylate can be added if necessary. Phosphoric acid (meth) acrylate improves the adhesion between aluminum, silver or a silver alloy and the cured adhesive, but may corrode the metal film, and its amount used is limited. Moreover, there is no problem even if it is not contained.

Further, in the present invention, in addition to the above components, if necessary, a silane coupling agent, a leveling agent, an antifoaming agent, a polymerization inhibitor, a light stabilizer (such as a hindered amine), an antioxidant, an antistatic agent, You may use together additives, such as a surface lubricant and a filler. Examples of such additives include, as silane coupling agents, KBM-502, KBM-503, KBM-5103, KBM-802, KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd .; Toray Dow Corning ( Z-6062, SH-6062, SH-29PA manufactured by Co., Ltd., BYK-333, BYK-3307, BYK-3500, BYK-3530, BYK-3570 manufactured by BYK-Chemie, Inc. as leveling agents, ) LA-82 manufactured by Adeka Corporation.
These additives may be contained in an amount of generally 0 to 10%, preferably 0 to 5%, based on the total amount of the resin composition of the present invention. Usually, there is no problem even if it is not contained.

The resin composition of the present invention can be obtained by mixing and dissolving the above components at room temperature to 80 ° C. and then filtering if necessary.
The viscosity of the resin composition of the present invention is 10 to 800 mPa · s, preferably 30 to 500 mPa · s, more preferably 30 to 400 mPa · s, still more preferably 50 to 300 mPa as measured at 25 ° C. with a B-type viscometer. -S.
As an example of the resin composition of the present invention, the component (A) is 5 to 90% by weight, the component (B) and / or the component (C) is 5 to 90% by weight, and (D) with respect to the entire resin composition. Examples thereof include an ultraviolet curable resin composition having 1 to 15% by weight of components and a total amount of (A) to (D) of 100%.

式中、ＲはＨ又はＣＨ_３、ｎは１０～２５の整数を示す、
である上記（Ｉ）又は（ＩＩ）に記載の樹脂組成物。 The following resin resin composition can be mentioned as a preferable example of the composition of the resin composition of this invention preferable.
(I)
(I) (A) component is 5 to 90% by weight, (ii) (B) component or (C) component, or both (B) and (C) are 5% with respect to the total amount of the resin resin composition. A resin composition in which the content of the components (A) to (C) is 85 to 99% by weight and the component (D) is 1 to 15% by weight.
(II)
As an example of a more preferable resin composition, (i) (A) component is 10 to 40% by weight, (ii) (B) component or (C) component, or both (B) and (C) are 50 A resin composition in which the total amount of the components (A) to (C) is 90 to 99% by weight and the component (D) is 1 to 10% by weight.
(III)
(A) component is a (meth) acrylate having a fatty chain represented by the following formula (1):

In the formula, R represents H or CH ₃ , n represents an integer of 10 to 25,
The resin composition according to (I) or (II) above.

(IV)
The resin composition as described in (III) above, wherein the component (A) is a C10-C25 alkyl (meth) acrylate having a branched chain.
(V)
The branched C10-C25 alkyl (meth) acrylate is at least selected from the group consisting of isodecyl acrylate, isolauryl (meth) acrylate, isostearyl (meth) acrylate, isocetyl (meth) acrylate, and isobehenyl (meth) acrylate The resin composition according to (IV), which is a kind.
(VI)
The resin composition according to the above (IV), wherein the C10-C25 alkyl (meth) acrylate having a branched chain is at least one selected from the group consisting of isodecyl acrylate, isostearyl (meth) acrylate, and isocetyl (meth) acrylate. .
(VII)
The resin composition as described in (IV) above, wherein the C10-C25 alkyl (meth) acrylate having a branched chain is isostearyl (meth) acrylate.
(VIII)
Component (B) is composed of isobornyl (meth) acrylate, propylene oxide-modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, and hydroxypivalaldehyde-modified trimethylolpropane di (meth) acrylate. The resin composition according to any one of (I) to (VII) above, which is at least one (meth) acrylate monomer selected from the group consisting of:

(IX)
(B) The resin composition as described in (VIII) above, wherein the component is either isobornyl (meth) acrylate or hydroxypivalaldehyde-modified trimethylolpropane di (meth) acrylate.
(X)
The resin composition according to any one of the above (I) to (IX), wherein the component (C) is a urethane (meth) acrylate obtained by a reaction between an organic polyisocyanate and a hydroxy (meth) acrylate compound.
(XI)
The resin composition according to item (X), wherein the hydroxy (meth) acrylate compound is a hydroxy-substituted C2-C10 aliphatic (meth) acrylate.
(XII)
The resin composition according to any one of (I) to (XI), wherein the component (B) is contained in an amount of 50 to 90% based on the total amount of the resin composition.
(XIII)
The resin composition according to any one of (I) to (XII) above, wherein the content of the component (C) is 0 to 50% with respect to the total amount of the components (B) and (C).

The resin composition of the present invention is suitable as a resin composition for a transparent intermediate layer of a multilayer optical disk.
In the case of DVD, the transparent resin intermediate layer is formed on (1) at least one of the first transparent resin substrate, the first recording layer, the substrate on which the first translucent reflective film layer is laminated, and the transparent resin stamper. The resin composition is applied by a spin coating method, a screen printing method, a roll coating method, or the like, and then bonded together and irradiated with ultraviolet rays from the transparent resin stamper side. Or (2) the transparent resin stamper is coated with the resin composition of the present invention by the above method and then cured with ultraviolet rays, and the first transparent resin substrate, the first recording layer, and the first translucent reflective film layer are laminated. It is also possible to form the substrate by adhering it with an arbitrary ultraviolet curable resin. The formation method (1) is preferable in that the production process can be omitted and the production cost can be reduced. In addition, a transparent resin intermediate layer is formed on a Blu-ray disc in the same manner as DVD. Generally, polycarbonate resin is used for the 0.6 mm first transparent resin substrate for DVD and HD-DVD and the 1.1 mm resin substrate for Blu-ray Disc.

Examples of the transparent resin stamper include acrylic resins, methacrylic resins, polycarbonate resins, polyolefin resins (particularly amorphous polyolefins), polyester resins, polystyrene resins, and epoxy resins. Among these, amorphous polyolefin is preferable from the viewpoint of peelability after curing the 2P agent, low hygroscopicity, shape stability, and the like, and polycarbonate resin is preferable from the viewpoint of material cost. Either transparent resin stamper can be used for the 2P curable resin composition of the present invention.
The ultraviolet curable resin composition of the present invention gives a cured product by irradiation with active energy rays. Examples of the active energy ray include ultraviolet light to near ultraviolet light. Examples of the light source include a low pressure, a high pressure, an ultrahigh pressure mercury lamp, a metal halide lamp, a (pulse) xenon lamp, an electrodeless lamp, an ultraviolet light emitting diode, and the like. The cured product is also included in the present invention.

For the recording layer formed on the transparent resin intermediate layer of the cured product, either an organic dye or a phase change material can be used. For example, organic dyes include metal-containing azo, polymethine, and phthalocyanine, and phase change materials include Sb and Te, In, Ag, Au, Bi, Se, Al, P, Ge, Si, C, V, W , Ta, Zn, Ti, Ce, Tb, Sn, and Pb are added.
In addition, the resin composition of the present invention can be used for either an optical disc or a Blu-ray disc having a structure in which a polycarbonate substrate is bonded.

Examples of the coating method include a spin coating method, a 2P method, a roll coating method, and a screen printing method.

Further, since a blue laser having a thickness of about 400 nm is used for reading and / or writing in the next generation high-density optical disk, a cured product having a film thickness of 90-100 μm, preferably a transmittance of 405 nm at 100 μm is 80% or more. Preferably, it is 90% or more.
The transmittance can be determined by preparing a 100 μm film and measuring the absorbance value at 405 nm of the film using a spectrophotometer (U-3310, manufactured by Hitachi High-Technologies Corporation).

Hereinafter, the present invention will be described in detail with reference to examples.
In addition, the value of the viscosity described in Table 1 is a value measured at 25 ° C. with a B-type viscometer. The transmittance values shown in Table 1 are values measured with a spectrophotometer (product number: U-3310, manufactured by Hitachi High-Technologies Corporation) after forming a cured film having a thickness of 100 μm.
Examples and Test Examples Table 1 shows the constituent materials, the amounts used, and the evaluation results of the described items for the resin compositions of Example 1-6 and Comparative Example 1-4. In addition, "part" in description shows a weight part.

In addition, each component shown with the abbreviation in Table 1 is as follows.
ISA: Isostearyl acrylate, Shinnakamura Chemical Co., Ltd. ICA: Isocetyl acrylate, Kyoeisha Chemical Co., Ltd. IDA: Isodecyl acrylate, Kyoeisha Chemical Co., Ltd. SA: Stearyl acrylate, NOF Corporation CA: Cetyl acrylate, NOF Corporation IBA: Isobornyl acrylate, Osaka Organic Chemical Co., Ltd. R-604: Hydroxypivalaldehyde-modified trimethylolpropane diacrylate, Nippon Kayaku Co., Ltd. R-684: Tricyclodecane dimethylol di Acrylate, Nippon Kayaku Co., Ltd. NPG-2P: Propylene oxide modified neopentyl glycol diacrylate, Dai-ichi Kogyo Seiyaku Co., Ltd. FA-512A: Dicyclopentenyloxyethyl acrylate, Hitachi Chemical Co., Ltd. THE-3 0: Hydropivalaldehyde-modified trimethylolpropane acrylate, Nippon Kayaku Co., Ltd. RP-1040: Pentaerythritol ethylene oxide-modified tetraacrylate, Nippon Kayaku Co., Ltd. DPHA: Dipentaerythritol hexane acrylate, Nippon Kayaku Co., Ltd. UX-5000: 6-functional urethane acrylate, Nippon Kayaku Co., Ltd. Irgacure ^RTM 184: 1-hydroxycyclohexyl phenyl ketone, manufactured by Ciba Specialty Chemicals Co., Ltd.
C1: Urethane acrylate obtained by reacting isophorone diisocyanate and hydroxyethyl acrylate in a molar ratio of 1: 2.

(Preparation of sample for evaluation)
A sample disk for evaluation was produced by the following methods 1 to 3 using the obtained ultraviolet curable resin composition.
1. Inner circumference of a polycarbonate substrate (first substrate) having a diameter of 120 mm / 0.6 mm, on which an azo dye layer as a recording layer, a reflective film layer, and a ZnS / SiO ₂ layer as a dielectric layer are formed A polycarbonate stamper was placed on the transparent resin prepared so as not to allow air bubbles to enter above, and was bonded by spin coating at 2000 rpm for 4 seconds.
2. A high pressure mercury lamp (80 W / cm) was irradiated from the polycarbonate stamper side at 400 mJ / cm ² to cure the second ultraviolet curable resin composition.
3. Using a disk peeling device (Origin Electric Co., Ltd.), the polycarbonate stamper (transparent resin stamper) was peeled off to prepare a sample disk for evaluation.

(A) Peelability test A disk peeling device (Origin Electric Co., Ltd.) was used to measure the peel strength from the polycarbonate stamper when the above sample disk for evaluation (diameter 120 mm: radius 60 mm) was prepared (FGC-5B, It was carried out by measuring with Nidec Symbol Corporation.
Judgment of good peeling was made according to the following criteria.
○ ・ ・ ・ Peel strength 1.5kgf or less
× ・ ・ ・ Peel strength 1.5kgf or more

(B) Warpage test The value of warpage of the resin layer is a 120 mm / 0.6 mm diameter polycarbonate in which an azo dye layer as a recording layer, a reflective film layer, and a ZnS.SiO ₂ layer as a dielectric layer are formed. Each resin composition was applied on the inner periphery of a bonnet substrate (first substrate) with a spin coater so that the film thickness would be 10 ± 3 μm after curing, and MT-146 (Dr. (Manufactured by Schenk). Since the warpage value increases as the outer circumference is reached, the evaluation was performed with a warp value (angle) of 56 mm from the center of the disk near the outermost circumference.
The initial warpage was calculated by the following (Formula 1).
(Formula 1) Warpage change amount upon curing (degrees) = warp of disk after application and curing of ultraviolet curable resin composition (degree) −warpage of disk before application of ultraviolet curable resin composition (degree)
The unit of warpage is displayed in degrees.
○: The amount of change in warping during curing is less than ± 0.1 degrees
X: The amount of change in warping during curing is ± 0.1 degrees or more

(C) Durability test As a durability test, the sample disk produced in the warp test process was allowed to stand for 96 hours under conditions of high temperature and high humidity of 80 ° C. and 85%, and further warped after being stored at room temperature for 24 hours. Was compared with the angle of the warp before the test (before placing under high temperature and high humidity), and the amount of change in the angle of the warp was calculated. Since the value of the warp increases as the outer periphery is reached, the evaluation was performed with a warp value of 56 mm from the center of the disk close to the outermost periphery. Further, MT-146 (manufactured by Dr. schenk), which is a mechanical characteristic device for optical disks, was used for the measurement.
The amount of change (degree) between the warp after the durability test and the initial warp was calculated by the following (Formula 2).
(Formula 2) Warpage change after endurance test = disc warp (degree) after endurance test-disc warp (degree) before test
○ ... War change after durability test is less than ± 0.5 degrees
× ... Warpage variation after durability test is ± 0.5 degrees or more

As is apparent from Table 1, the ultraviolet curable resin composition of the present invention and Examples 1 to 6 which are cured products thereof are compared with Comparative Examples 1 to 4 which do not use a (meth) acrylate having a fatty chain. Even after being placed under high temperature and high humidity (after endurance test), the amount of change in warpage is small. In Comparative Examples 2 and 3 using a plurality of polyfunctional acrylate monomers, the peel strength is strong and the peelability is poor. In Comparative Example 4, the peelability is good, but as described above, after the durability test. The amount of warpage change is large, and the warpage during curing is also large as described below.
In other words, the amount of change in warping during curing is as very small as 0.08 to 0.09 degrees in the ultraviolet curable resin composition of the present invention. In Comparative Example 1, the amount of change in warping during curing is the same, but the peelability from the resin stamper is poor, and the amount of change in warpage after the durability test is large. In Comparative Example 2, Comparative Example 3, and Comparative Example 4, the amount of change in warping during curing is relatively large, 0.15 to 0.36 degrees.
Further, regarding the viscosity of the ultraviolet curable resin composition of the present invention, the viscosity is in the range of 30 to 500 mPa · s, which is suitable for resin layer formation. Furthermore, the light transmittance of the cured product exceeds 90%, which is excellent in terms of light transmittance.
As is apparent from the above, the ultraviolet curable resin composition of the present invention is a transparent resin layer (intermediate layer) having a concavo-convex pattern made of a stamper, particularly a polycarbonate stamper, directly on a reflective layer or dielectric layer on a disk substrate. The resin composition is suitable for forming a (resin layer) and is very useful for uniformly forming a recording layer and a reflective film layer on the concavo-convex pattern.

The ultraviolet curable resin composition of the present invention and the cured product thereof are excellent as a 2P agent having excellent releasability from a resin stamper, and having a small change in warpage upon curing and after placing a multi-layer disc under high temperature and high humidity. . Further, it is possible to provide an ultraviolet curable resin capable of omitting the adhesive layer and forming the intermediate resin layer with one liquid.

Claims (12)

A multilayer optical disk comprising (A) a (meth) acrylate having a fatty chain, (B) a (meth) acrylate monomer and / or (C) a urethane (meth) acrylate, and (D) a photopolymerization initiator. UV curable resin composition. (A) (meth) acrylate having a fatty chain is lauryl (meth) acrylate, stearyl (meth) acrylate, cetyl (meth) acrylate, behenyl (meth) acrylate, isolauryl (meth) acrylate, isostearyl (meth) acrylate, The ultraviolet curable resin composition for multilayer optical disks according to claim 1, which is one or more selected from the group consisting of isocetyl (meth) acrylate and isobehenyl (meth) acrylate. (B) (meth) acrylate monomer is isobornyl (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, and hydroxypivalaldehyde modified trimethylolpropane di ( The ultraviolet curable resin composition for multilayer optical disks according to claim 1, wherein the ultraviolet curable resin composition is one or more selected from the group consisting of (meth) acrylates. The component (A) is 5 to 90% by weight, the component (B) and / or the component (C) is 5 to 90% by weight, and the component (D) is 1 to 15% by weight based on the entire resin composition. The ultraviolet curable resin composition for multilayer optical disks according to any one of claims 1 to 3. An optical disc having a cured product obtained by irradiating the resin composition according to claim 1 with ultraviolet rays. (A) (meth) acrylate having a fatty chain represented by the following formula (1),

In the formula, R represents H or CH ₃ , n represents an integer of 10 to 25,
And (B) isobornyl (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, and hydroxypivalaldehyde modified trimethylolpropane di (meth) acrylate At least one (meth) acrylate monomer selected from: or (C) urethane (meth) acrylate obtained by reaction of an organic polyisocyanate with a hydroxy (meth) acrylate compound,
And (D) a photopolymerization initiator,
Containing
For the total amount of the resin composition,
(I) 5 to 90% by weight of component (A),
(Ii) The component (B) or the component (C), or both (B) and (C) is 5 to 90% by weight, and the total amount of the components (A) to (C) is 85 to 99% by weight. Yes,
(Iii) The component (D) is 1 to 15% by weight,
UV curable resin composition. The ultraviolet curable resin composition according to claim 6, wherein the fatty chain of (meth) acrylate having a fatty chain is a fatty chain having a branched chain. The (meth) acrylate having a fatty chain is at least one selected from the group consisting of isodecyl acrylate, isolauryl (meth) acrylate, isostearyl (meth) acrylate, isocetyl (meth) acrylate, and isobehenyl (meth) acrylate. The ultraviolet curable resin composition according to claim 7. 7. The organic polyisocyanate is at least one diisocyanate selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, and diphenylmethane-4,4′-diisocyanate, or dicyclopentanyl isocyanate. The ultraviolet curable resin composition described in 1. The ultraviolet curable resin composition according to claim 6, wherein the hydroxy (meth) acrylate compound is a hydroxy-substituted C2-C10 aliphatic (meth) acrylate. Use of the ultraviolet curable resin composition according to claim 6 for an intermediate resin layer of a multilayer disk. A multilayer disc having a cured product layer of the ultraviolet curable resin composition according to claim 6.