JP2013145615A - Active energy ray curable composition for interlayer of multilayer structure optical information medium and multilayer structure optical information medium - Google Patents

Abstract

An active energy ray-curable composition for an intermediate layer of a multilayer structure optical information medium for forming an intermediate layer with little decrease in adhesion to a recording layer with respect to changes in temperature and humidity, and reduction in adhesion Provided is a multilayered optical information medium having few intermediate layers.
[Solution]
ACTIVITY FOR INTERLAY LAYER OF MULTILAYER STRUCTURE OPTICAL INFORMATION MEDIUM FOR FORMING INTERMEDIATE LAYER OF MULTILAYER STRUCTURE OPTICAL INFORMATION MEDIUM HAVING AT LEAST TWO INFORMATION RECORDING LAYERS AND TWO INTERMEDIATE INFORMATION RECORDING LAYERS An energy ray-curable composition comprising a polymerizable compound and a photopolymerization initiator having a mass reduction rate of 4% or less when held at 110 ° C. for 1 hour, and an intermediate layer is a cured product of the composition Multi-layered optical information medium that is a product.
[Selection figure] None

Description

  The present invention relates to an active energy ray-curable composition for an intermediate layer of a multilayer structure optical information medium and a multilayer structure optical information medium.

  As an optical information medium, a digital versatile disk (hereinafter referred to as “DVD”) is known. Also known as a large-capacity optical information medium exceeding DVD is a type of Blu-ray disc (hereinafter referred to as “BD”) that reads or writes information with a blue-violet laser having a wavelength of about 405 nm. Furthermore, a multilayer structure optical information medium in which an information recording layer (hereinafter referred to as “recording layer”) of an optical information medium such as a DVD or a BD is multilayered to increase the capacity is also known.

  The multilayer optical information medium requires a transparent light transmission layer (hereinafter referred to as “intermediate layer”) that separates the translucent recording layer from other recording layers with a certain thickness. As a method for forming the intermediate layer, for example, an active energy ray-curable composition is desired and fixed between a transparent mold such as a polycarbonate having a fine uneven shape corresponding to a signal or a transparent mold such as a transparent glass and a substrate. A method is known in which a transparent mold is released after being injected and cured to a film thickness.

  As an active energy ray-curable composition used for forming such an intermediate layer, for example, Patent Document 1 discloses a composition containing two specific types of components having a (meth) acryloyl group.

JP 2011-116969 A

  However, the intermediate layer obtained by curing the composition described in the example of Patent Document 1 is said to have a large decrease in adhesion to the recording layer (hereinafter referred to as “adhesion”) with respect to changes in temperature and humidity. There was a problem. Therefore, an object of the present invention is to provide an active energy ray-curable composition for an intermediate layer of a multilayer structure optical information medium for forming an intermediate layer with little decrease in adhesion. Another object of the present invention is to provide a multi-layered optical information medium having an intermediate layer with little decrease in adhesion to the recording layer with respect to changes in temperature and humidity.

As a result of intensive studies, the present inventors have found that the above problem can be solved by using a specific photopolymerization initiator, and have reached the present invention.
In a first aspect, the present invention provides a multilayer for forming the intermediate layer of a multilayer structure optical information medium having at least two information recording layers and an intermediate layer having a thickness of 3 to 30 μm between two adjacent information recording layers. The present invention relates to an active energy ray-curable composition for an intermediate layer of a structured optical information medium, comprising a polymerizable compound and a photopolymerization initiator having a mass reduction rate of 4% or less when held at 110 ° C. for 1 hour. .

  In the second aspect, the present invention provides the photopolymerization initiator in the first aspect is 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2. For intermediate layer of multilayer optical information medium which is -methyl-propan-1-one or 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one The present invention relates to an active energy ray-curable composition.

  In a third aspect, the present invention relates to a multilayer optical information medium having at least two information recording layers and an intermediate layer having a thickness of 3 to 30 μm between two adjacent information recording layers, and a part of the intermediate layer Or it is related with the multilayer structure optical information medium which is the hardened | cured material of the active energy ray curable composition for intermediate | middle layers of the multilayer structure optical information medium in the 1st or 2nd aspect entirely.

  The intermediate layer obtained by curing the active energy ray-curable composition for the intermediate layer of the multilayer optical information medium of the present invention (hereinafter referred to as “transfer composition”) is resistant to the recording layer against changes in temperature and humidity. Little decrease in adhesion.

  The present invention is a transfer composition for forming part or all of an intermediate layer between two adjacent information recording layers in a multilayer structure optical information medium having at least two information recording layers. The transfer composition contains a polymerizable compound and a photopolymerization initiator.

  The transfer composition of the present invention preferably contains the following components (A) and (B) as the polymerizable compound. In the present specification, “(meth) acryloyl group” means “acryloyl group” or “methacryloyl group”.

<(A) component>
In the component (A), at least one hydroxyl group of the polyhydric alcohol is esterified with (meth) acrylic acid, and part or all of the remaining hydroxyl groups are esterified with a fatty acid other than (meth) acrylic acid. It is a polymerizable compound having a good structure. Here, the fatty acid is not particularly limited as long as it is other than (meth) acrylic acid. For example, saturated fatty acid includes butyric acid, caproic acid, lauric acid, stearic acid, melicic acid, and the like. Examples of unsaturated fatty acids include oleic acid, linoleic acid, linolenic acid, and eicosapentaenoic acid.
Component (A) is a component that improves curability, hardness of the cured product, and mold releasability from a mold, particularly a polycarbonate mold.

  The component (A) can be synthesized, for example, by an esterification reaction between a polyhydric alcohol and (meth) acrylic acid. When a fatty acid residue is introduced into the component (A), it can be similarly synthesized by an esterification reaction using a fatty acid.

  The content of the component (A) in the transfer composition of the present invention is preferably in the range of 30% by mass to 90% by mass in 100% by mass of the total amount of polymerizable compounds. When the content of the component (A) is 30% by mass or more, curability, hardness of the cured product and mold release from the mold are improved, and when it is 50% by mass or more, the mold release is further improved. When the content of the component (A) is 90% by mass or less, the viscosity of the transfer composition is decreased, and it is more preferably 70% by mass or less. By reducing the viscosity of the transfer composition, the coating properties are improved, and coating with a thin film is facilitated. From the viewpoint of low warpage, it is preferable that the number of (meth) acryloyl groups in the component (A) is small.

  The component (A) preferably contains any one of the polymerizable compounds represented by the following formulas (1) to (3).

(In Formula (1), R ¹ represents a (meth) acryloyl group or hydrogen, and at least one is a (meth) acryloyl group. R ² represents an alkinoyl group or alkanoyl group having ^{2 to} 31 carbon atoms, and (A may be any of a chain, a branch, and a ring. A represents an integer of 1 to 6, b represents an integer of 0 to 5, and a + b = 6.)

(In Formula (2), R ¹ represents a (meth) acryloyl group or hydrogen, and at least one is a (meth) acryloyl group. R ² represents an alkinoyl group or alkanoyl group having ^{2 to} 31 carbon atoms; (C may be any of a chain, a branch, and a ring, c is an integer of 1 to 4, d is an integer of 0 to 3, and c + d = 4.)

(In the formula (3), R represents a (meth) acryloyl group, an alkinoyl group having 2 to 31 carbon atoms or an alkanoyl group, hydrogen, and may be linear, branched or cyclic, at least one of which ) An acryloyl group, e, f, g, n represent integers, n represents the number of repeating units, e + f + g = n + 2.

As the polymerizable compound represented by the formula (1), for example,
Polymerizable compound modified with an average of 6 acryloyl groups per molecule with respect to dipentaerythritol: trade name “Kayarad DPHA”, manufactured by Nippon Kayaku Co., Ltd. [In the formula (1), R ¹ is an acryloyl group, a = 6 , B = 0],
Polymeric compound modified with an average of 1 ethyloyl group and an average of 5 acryloyl groups per molecule for dipentaerythritol: trade name “Kayarad D-310”, manufactured by Nippon Kayaku Co., Ltd. [Formula (1) In which R ¹ is an acryloyl group, R ² is an ethyloyl group, a = 5, b = 1],
Polymeric compound modified with an average of one alkinoyl group or alkanoyl group and an average of five acryloyl groups per molecule for dipentaerythritol: trade name “NK Ester ADP-51EH”, manufactured by Shin-Nakamura Chemical Co., Ltd. [In the formula (1), R ¹ is an acryloyl group, R ² is an alkanoyl group or alkinoyl group having 2 or more carbon atoms, a = 5, b = 1],
Polymeric compound modified with an average of 2 ethyloyl groups and an average of 4 acryloyl groups per molecule for dipentaerythritol: trade name “Kayarad D-320”, manufactured by Nippon Kayaku Co., Ltd. [Formula (1) Wherein R ¹ is an acryloyl group, R ² is an ethyloyl group, a = 4, b = 2],
Polymeric compound modified with an average of 3 ethyloyl groups and an average of 3 acryloyl groups per molecule relative to dipentaerythritol: trade name “Kayarad D-330”, manufactured by Nippon Kayaku Co., Ltd. [Formula (1) R ¹ is an acryloyl group, R ² is an ethyloyl group, a = 3, b = 3] and the like.

As the polymerizable compound represented by the formula (2), for example,
Polymerizable compound modified with an average of 4 acryloyl groups per molecule with respect to pentaerythritol: trade name “NK Ester A-TMMT”, manufactured by Shin-Nakamura Chemical Co., Ltd. [In the formula (2), R ¹ is an acryloyl group, c = 4, d = 0],
Polymerizable compound modified with an average of one alkinoyl group or alkanoyl group and an average of three acryloyl groups per molecule for pentaerythritol: trade name “ATM-31EH”, manufactured by Shin-Nakamura Chemical Co., Ltd. [formula ( 2), R ¹ is an acryloyl group, R ² is an alkinoyl group or alkanoyl group having ^{2 to} 31 carbon atoms, c = 3, d = 1],
Polymerizable compound modified with an average of one alkinoyl group or alkanoyl group and three average acryloyl groups per molecule for pentaerythritol: trade name “NK Ester ATM-OSA”, manufactured by Shin-Nakamura Chemical Co., Ltd. [ In the formula (2), R ¹ is an acryloyl group, R ² is an alkinoyl group or alkanoyl group having ^{2 to} 31 carbon atoms, c = 3, d = 1] and the like.

Examples of the polymerizable compound represented by the formula (3) include:
Polymerizable compound obtained by modifying fatty acid-modified polyglycerin with an acryloyl group: trade name “NK ester ADPGL-55”, manufactured by Shin-Nakamura Chemical Co., Ltd. [In the formula (3), R is an acryloyl group or having 2 to 31 carbon atoms. An alkanoyl group or an alkinoyl group, provided that at least one is an acryloyl group].

As the component (A) other than the polymerizable compound represented by the formulas (1) to (3), for example,
A polymerizable compound modified with an average of 1 lauryl group and an average of 2 acryloyl groups per molecule for trimethylolpropane,
A polymerizable compound modified with an average of 2 laurylyl groups and an average of 2 acryloyl groups per molecule with respect to ditrimethylolpropane,
Examples thereof include polymerizable compounds modified with an average of 1 lauryl group per molecule and an average of 2 acryloyl groups with respect to tris (2-hydroxyethyl) isocyanurate.

  As the component (A), dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified dipentaerythritol triacrylate, pentaerythritol tetra from the viewpoint of releasability, low warpage, viscosity, and curability. An acrylate is more preferable, and a polymerizable compound modified with an average of 3 ethyloyl groups and an average of 3 acryloyl groups per molecule with respect to dipentaerythritol is particularly preferable.

<(B) component>
The component (B) is a component that lowers the viscosity of the transfer composition without impairing the releasability of the cured product from the mold, and is a component other than the component (A). The component (B) is characterized by low dissolving power in the mold and is negative in the following polycarbonate resin solubility test.

(Polycarbonate resin solubility test)
Polycarbonate resin (trade name “Panlite L-1225-Z100”, manufactured by Teijin Chemicals Ltd.) was injection molded at a resin temperature of 340 ° C., a mold temperature of 90 ° C., and an injection speed of 120 mm / sec. 5 cm × 5 cm × 3 mm). About this polycarbonate resin board, the haze value before a test is measured using a haze meter (HM-65W, Murakami Color Research Laboratory Co., Ltd.). Next, on this polycarbonate resin plate, 0.3 ml of a monomer as a test solution is dropped, and left standing at 20 ° C. for 10 minutes. Thereafter, the monomer is wiped off with Wes (trade name “Kim Towel”, Nippon Paper Crecia Co., Ltd.). Using a haze meter (HM-65W, manufactured by Murakami Color Research Co., Ltd.), the haze value of the portion of the polycarbonate resin plate after the liquid to be tested was dropped and wiped off was measured. Judge resin solubility.
Positive: Increased haze value after test> 10.0
Negative: Increased haze value after test ≦ 10.0

  When the haze value before the test is Hzb% and the haze value after the test is Hza%, the increased haze value ΔHz is a value represented by Hza−Hzb. When the increased haze value is 10.0 or less, the release property of the cured product from the mold is improved. When it is 5.0 or less, the releasability of the cured product from the mold is further improved.

  It is preferable that content of (B) component exists in the range of 10 mass%-70 mass% in the total amount of 100 mass% of a polymeric compound. When the content of the component (B) is 10% by mass or more, the viscosity of the transfer composition is lowered, and when it is 30% by mass or more, the viscosity is further lowered. When the content of the component (B) is 70% by mass or less, the releasability from the mold is improved, and when it is 50% by mass or less, the releasability is further improved.

  The component (B) preferably has a viscosity at 25 ° C. of 400 mPa · s or less from the viewpoint of the viscosity of the transfer composition. (B) The viscosity of a component is measured by the method in the below-mentioned Example. Specifically, isobornyl (meth) acrylate, hydroxypivalate neopentyl glycol ester di (meth) acrylate, ε-caprolactone modified hydroxypivalate neopentyl glycol ester di (meth) acrylate, γ-butyrolactone modified hydroxypivalate neopentyl Glycol ester di (meth) acrylate, δ-valerolactone modified hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, α-methyl-γ-butyrolactone modified neopentyl glycol ester di (meth) acrylate, β-propiolactone modified Neopentyl glycol ester di (meth) acrylate, ethylene oxide modified hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, Opentyl glycol modified trimethylolpropane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, hydroxypivalate trimethylolpropane tri (meth) acrylate, tris ((meth) And acryloyloxyethyl) isocyanurate.

  Among them, isobornyl (meth) acrylate, hydroxypivalic acid neopentyl glycol ester di (meth) acrylate, ε-caprolactone modified hydroxypivalic acid neopentyl glycol ester di ( More preferred are (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, isobornyl acrylate, hydroxypivalate neopentyl glycol diacrylate, neopentyl glycol modified tri Methylolpropane diacrylate and tricyclodecane dimethanol acrylate are particularly preferred.

  In the transfer composition of the present invention, it is preferable to use a component that hardly dissolves the mold from the viewpoint of releasability from the mold. For example, when a polycarbonate resin mold is used, it is preferable that the content of the (meth) acrylate or organic solvent having high solubility in the polycarbonate resin as a component of the transfer composition is small, and it is more preferable not to include it.

  The transfer composition of the present invention contains a photopolymerization initiator having a mass reduction rate (hereinafter referred to as “mass reduction rate”) of 4% or less when held at 110 ° C. for 1 hour. By using such a specific photopolymerization initiator, a decrease in adhesion can be reduced. The reason why the adhesiveness of the conventional intermediate layer is lowered is considered to be that the photopolymerization initiator remaining in the intermediate layer volatilizes at a high temperature, whereby the intermediate layer contracts and peels off from the recording layer. Since the mass reduction rate of the photopolymerization initiator contained in the conventional active energy ray-curable composition for intermediate layer exceeds 4%, the amount of volatilization of the photopolymerization initiator from the intermediate layer is large, resulting in a decrease in adhesion. large. On the other hand, since the mass reduction rate of the photopolymerization initiator contained in the transfer composition of the present invention is 4% or less, there is little decrease in adhesion. Even in the case where the intermediate layer described later is composed of a multilayer composed of a cured product of the transfer composition of the present invention and another layer such as an adhesive layer, the shrinkage of the cured product of the transfer composition of the present invention is also reduced. Since the influence also affects the surface of the intermediate layer on the recording layer side, the use of the transfer composition of the present invention reduces the decrease in the adhesion of the intermediate layer. As described above, since the effect of suppressing the decrease in adhesion depends on the photopolymerization initiator, it does not depend on the type of the polymerizable compound contained in the transfer composition of the present invention.

The mass reduction rate of the photopolymerization initiator is measured by a method based on ASTM D-2623. That is, after taking 2.0 g (mass before heating) of the photopolymerization initiator on an aluminum container, the photopolymerization initiator was heated for 1 hour with a dryer at 110 ° C., and the mass after heating was measured. Calculate the reduction rate.
Mass reduction rate (%) = {(mass before heating−mass after heating) / mass before heating} × 100

  Examples of the photopolymerization initiator having a mass reduction rate of 4% or less include 2,4,6-trimethylbenzophenone, methylorthobenzoylbenzoate, 4-phenylbenzophenone, t-butylanthraquinone, 2-ethylanthraquinone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl- {4- (methylthio) phenyl} -2-morpholino-1-propanone, 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4- Trimethylpentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphospho Fin oxide, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl - propionyl) - benzyl} - phenyl] -2-methyl - propan-1-one, and the like. A photoinitiator can be used 1 type or in combination of 2 or more types.

  In the case of a transfer composition for a multilayer optical information medium that is read and written using a blue-violet laser, the blue-violet laser transmittance of the cured product is good. 4,6-trimethylbenzophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl- {4- (methylthio) phenyl} 2-morpholino-1-propanone, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) -benzyl} -phenyl] -2-methyl-propan-1-one is preferred. .

  Among them, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one or 1- [4- (2 -Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one is particularly preferred because it can improve adhesion.

  The content of the photopolymerization initiator in the transfer composition can be appropriately selected in consideration of curability under the curing conditions to be used, but is 1 to 20 parts by mass with respect to 100 parts by mass of the total amount of polymerizable compounds. It is preferable to be within the range. When the content of the photopolymerization initiator is 1 part by mass or more, curability is improved, and when it is 5 parts by mass or more, curability is further improved. When the content of the photopolymerization initiator is 20 parts by mass or less, the amount of the photopolymerization initiator remaining in the intermediate layer is small, and when it is 10 parts by mass or less, the residual amount is further reduced.

  In addition to the polymerizable compound and photopolymerization initiator, the transfer composition of the present invention, if necessary, a reactive oligomer such as urethane (meth) acrylate, another photopolymerization initiator, a metal adhesion improver, Release agent, thermoplastic polymer, slip agent, leveling agent, antioxidant, light stabilizer, UV absorber, polymerization inhibitor, silane coupling agent, inorganic filler, organic filler, surface-organized inorganic filler, You may contain well-known materials etc., such as an organic solvent. However, as a component of the transfer composition, it is preferable to use a component that is difficult to dissolve the template from the viewpoint of releasability from the template. For example, when a polycarbonate resin mold is used, it is preferable that the content of the component having high solubility in the polycarbonate resin is small, and it is more preferable not to include it.

  The viscosity of the transfer composition of the present invention is preferably in the range of 10 to 3000 mPa · s, more preferably in the range of 50 to 500 mPa · s at 25 ° C. from the viewpoint of workability and defoaming properties. . The viscosity can be adjusted by a method of changing the type and amount of the polymerizable compound. For example, in the case of the transfer composition containing the component (A) and the component (B), the viscosity increases when the content of the component (A) is increased, and the viscosity decreases when the content is decreased. It can be adjusted to the desired viscosity.

  The present invention also relates to a multilayer structure optical information medium having at least two information recording layers and an intermediate layer having a thickness of 3 to 30 μm between two adjacent information recording layers, wherein a part or all of the intermediate layer is formed. It is a multilayer structure optical information medium which is a cured product of the transfer composition of the present invention. Examples of such a multilayer optical information medium include DVD and BD. The multilayer optical information medium includes, for example, a substrate, a first recording layer (reflection film), an intermediate layer, a second recording layer (reflection film), a light transmission layer (protective layer), and the like. The intermediate layer may be composed of only a transfer layer obtained by curing the composition, or may be composed of a multilayer including other layers such as an adhesive layer. The thickness of the intermediate layer can be adjusted by adjusting the thickness of the transfer composition when forming the transfer layer and the thickness of the composition for the adhesive layer when forming the adhesive layer.

  The intermediate layer of the multilayer structure optical information medium of the present invention is obtained, for example, after the transfer composition of the present invention is cured by irradiating an active energy ray between the surface having the concavo-convex shape of the mold and the recording layer on the substrate. The mold can be formed by releasing the mold.

  Examples of the active energy rays used for curing the transfer composition include known active energy rays such as ultraviolet rays and electron beams. The atmosphere for irradiating the transfer composition with active energy rays may be air or an inert gas such as nitrogen or argon. In curing the transfer composition, a method of curing by heating in addition to irradiation with active energy rays may be used in combination.

  When the transfer composition is irradiated with active energy rays through a transparent resin mold and cured, the better the light transmittance of the mold, the more advantageous the curing of the transfer composition. Therefore, examples of the mold material include acrylic resin, polycarbonate resin, polyolefin resin, and polystyrene resin. Among these, polycarbonate resins are preferable from the viewpoint of raw material costs. Examples of the uneven shape of the mold include an uneven pattern shape such as a spiral land, groove, or prepit.

  Examples of the material of the substrate of the multilayer optical information medium include transparent plastics such as acrylic resins, polycarbonate resins, polyolefin resins, polystyrene resins, and mixed resins thereof, inorganic glass, and the like. Of these, polycarbonate resins are preferred from the viewpoint of raw material costs. The material may be the same as or different from the mold.

  The recording layer of the multilayer optical information medium is composed of a reflective film, a recording film, and the like. Examples of the material for the reflective film include metal elements, metalloid elements, semiconductor elements, and compounds of these elements alone or in combination. Among these, Au, Ag, Cu, Al, etc. are preferable. As a material for the recording film, a material that can be used for a read-only medium, a phase change information medium, an organic dye type information medium, a pit formation type information medium, and the like may be appropriately selected and used. Specifically, Au, Ag, Ag · Pd · Cu alloy, aluminum, Al · Ti alloy, Ag · In · Te · Sb alloy, Ag · In · Te · Sb · Ge alloy, Ge · Sb · Te alloy, Examples thereof include Ge.Sn.Sb.Te alloys, Sb.Te alloys, Tb.Fe.Co alloys, and dyes.

As a manufacturing method of a multilayer structure optical information medium, the method of the following Examples 1-3 is mentioned, for example.
[Example 1] A production method in which a transfer composition is sandwiched between a substrate with a recording layer and a mold and cured. Between the surface on the first recording layer side on the substrate and the surface having an uneven shape of the transparent resin mold. After adjusting the sandwiched transfer composition of the present invention to a target thickness by spin coating, the transfer composition is cured by irradiating an active energy ray through the mold from the mold side. Thereafter, the mold is released to obtain an intermediate layer having the concavo-convex shape of the mold transferred to the surface. A second recording layer is formed on the obtained intermediate layer. A multilayer structure optical information medium can be obtained by forming a cover layer on the obtained second recording layer by using a spin coating method or the like. A hard coat layer may be formed on the surface of the cover layer as necessary.

[Example 2] Production method of sandwiching and curing a transfer composition between a substrate with an adhesive layer and a mold After adjusting the adhesive composition on a first recording layer on the substrate to a target thickness by spin coating, The adhesive layer is obtained by irradiating the adhesive composition with active energy rays. After adjusting the transfer composition of the present invention sandwiched between the surface on the adhesive layer side of the obtained substrate with the adhesive layer and the surface having a concavo-convex shape of the transparent resin mold to a target thickness by spin coating, The transfer composition is cured by irradiating an active energy ray from the mold side through the mold. Thereafter, the mold is released to obtain a cured product in which the uneven shape of the mold is transferred to the surface. Next, the second and subsequent recording layers are formed in the same manner as in Example 1.

[Example 3] A production method in which an adhesive composition is sandwiched and cured between a mold with a transfer layer and a substrate with a recording layer. The transfer composition of the present invention is applied by spin coating on a surface having an uneven shape of a transparent resin mold. After adjusting to the target thickness, a transfer layer-attached template is obtained by irradiating the transfer composition with active energy rays. The adhesive composition is sandwiched between the surface on the transfer layer side of the mold with the transfer layer and the surface on the recording layer side of the substrate, adjusted to the target thickness by spin coating, and then the active energy ray is applied from the mold side. The adhesive composition is cured by irradiation through the mold and the transfer layer. Thereafter, only the mold is released to obtain a cured product in which the uneven shape of the mold is transferred to the surface. Next, the second and subsequent recording layers are formed in the same manner as in Example 1.

  Hereinafter, the present invention will be described in detail with reference to examples. In the examples, various evaluation methods and evaluation criteria for the transfer composition and its cured product are as follows.

(1) Viscosity The viscosity (unit: mPa · s) of the transfer composition was measured for the composition at 25 ° C. using an E-type viscometer (TVE-20, manufactured by Toki Sangyo Co., Ltd.).

(2) Adhesiveness The sample disk was subjected to a 100-hour durability test under high-temperature and high-humidity conditions of 80 ° C. and 85% RH, and then the state of the intermediate layer was visually observed to evaluate the adhesiveness according to the following criteria.
○: There is no separation of the intermediate layer from the substrate with the recording layer. X: The intermediate layer is separated from the substrate with the recording layer.

[Example 1]
An optical information medium substrate (diameter 12 cm, plate thickness 1.1 mm, warp angle 0 degree) having a spindle holding hole at the center obtained by injection molding of polycarbonate resin was prepared. On the signal surface (track pitch 0.7 μm, groove width 0.3 μm, groove depth 0.2 μm) of this optical information medium substrate, a recording layer made of a silver thin film having a thickness of about 0.05 μm is formed by sputtering. Thus, a substrate with a recording layer was obtained.

On the recording layer of the obtained substrate with a recording layer, an active energy ray-curable composition (transfer composition) for an intermediate layer obtained by blending each raw material at the blending ratio shown in Table 1 was applied, and polycarbonate An optical information medium mold (diameter: 12 cm, plate thickness: 0.6 mm, warp angle: 0 degree, track pitch: 0.7 μm, groove width: 0.3 μm, groove depth: 0.2 μm) is attached so as to be in contact with the transfer composition. Combined. The transfer composition was spin-coated so that the film thickness after curing was 25 μm, and then irradiated with 500 mJ / cm ² of ultraviolet light from the mold side with a high-pressure mercury lamp to form a transfer layer made of a cured product of the transfer composition. . Thereafter, the sample disk composed of the substrate, the recording layer and the intermediate layer (transfer layer) was released from the mold, and the adhesion was evaluated. The obtained evaluation results are shown in Table 1.

[Examples 2-6, Comparative Examples 1-3]
A sample disk was produced in the same manner as in Example 1 except that the transfer composition was prepared at the blending ratio shown in Table 1 or Table 2. The evaluation results are shown in Tables 1 and 2.

  From the results of adhesion evaluation in Tables 1 and 2, the intermediate layers (Examples 1 to 6) formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of 4% or less are provided with a recording layer. The intermediate layer (Comparative Examples 1 to 3) formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of more than 4%, while having no peeling from the substrate, was obtained from the substrate with the recording layer. It was found that peeling occurred.

<Synthesis Example 1 (Preparation of Adhesive Composition)>
265 g of dicyclohexylmethane-4,4′-diisocyanate and 0.12 g of di-n-butyltin dilaurate were charged into a flask equipped with a heat retaining function, a reflux condenser, a stirring blade and a temperature sensor, and heated to 50 ° C. did. 325 g of polytetramethylene glycol (trade name “PTG650SN”, manufactured by Hodogaya Chemical Co., Ltd., mass average molecular weight = 650) was added dropwise over 4 hours in a state where the dropping funnel with a heat retaining function was heated to 40 ° C. Subsequently, after stirring at 40 degreeC for 2 hours, it heated up to 70 degreeC over 1 hour. Thereafter, 116 g of 2-hydroxyethyl acrylate was added dropwise over 2 hours, and the mixture was further stirred for 2 hours to synthesize urethane acrylate (UA).

  50 parts of UA obtained, 40 parts of tetrahydrofurfuryl acrylate, 10 parts of trimethylolpropane triacrylate, 5 parts of 1-hydroxycyclohexyl-phenylketone, 0.1 part of 2-methacryloyloxyethyl acid phosphate were prepared, and an adhesive composition was prepared. Prepared.

[Example 7]
A transfer obtained by blending each raw material in the blending ratio shown in Table 3 on the surface (surface having a groove) having an uneven shape of a polycarbonate optical information medium mold similar to that used in Example 1 After spin-coating the composition to a cured film thickness of 10 μm, by irradiating with 500 mJ / cm ² of ultraviolet light with a high-pressure mercury lamp, a transfer layer made of a cured product of the transfer composition is formed in the mold, A mold with a transfer layer was obtained.

After applying the adhesive composition produced in Synthesis Example 1 on the recording layer of the substrate with the recording layer obtained in the same manner as in Example 1, the mold with the transfer layer was pasted so that the transfer layer was in contact with the adhesive composition. In addition, spin coating was performed so that the film thickness of the adhesive layer was 15 μm, and 500 mJ / cm ² of ultraviolet light was irradiated from the mold side with the transfer layer with a high-pressure mercury lamp to form an adhesive layer made of a cured product of the adhesive composition. .
Thereafter, the sample disk composed of the substrate, the recording layer and the intermediate layer (adhesive layer and transfer layer) was released from the mold, and the adhesion was evaluated. The obtained evaluation results are shown in Table 3.

[Comparative Example 4]
A sample disk was manufactured in the same manner as in Example 7 except that the transfer composition was prepared at the blending ratio shown in Table 3. The evaluation results are shown in Table 3.

  From the results of the adhesion evaluation in Table 3, the intermediate layer (Example 7) consisting of a transfer layer and an adhesive layer formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of 4% or less, An intermediate layer composed of a transfer layer and an adhesive layer formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of more than 4%, while there is no peeling from the substrate with the recording layer (Comparative Example 4) Was found to be peeled off from the substrate with the recording layer.

[Example 8]
On the recording layer of the substrate with the recording layer obtained by the same method as in Example 1, the adhesive composition was spin-coated so as to have a film thickness of 15 μm and irradiated with 500 mJ / cm ² of ultraviolet rays with a high-pressure mercury lamp. To obtain an adhesive layer. On the adhesive layer, the transfer composition obtained by blending each raw material at the blending ratio shown in Table 4 was applied, and further bonded so that the surface having the uneven shape of the polycarbonate mold was in contact with the transfer composition. Thereafter, the transfer composition was spin-coated so that the film thickness after curing was 10 μm, and irradiated with 500 mJ / cm ² of ultraviolet light from the mold side with a high-pressure mercury lamp.
Thereafter, the mold was released from the laminate comprising the substrate, the reflective film, the transfer layer and the adhesive layer, and the adhesion was evaluated. The evaluation results are shown in Table 4.

[Comparative Example 5]
A transfer composition was prepared at a blending ratio shown in Table 4, and a sample disk was produced in the same manner as in Example 8. The evaluation results are shown in Table 4.

  From the results of adhesion evaluation in Table 4, the intermediate layer (Example 8) consisting of a transfer layer and an adhesive layer formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of 4% or less, An intermediate layer composed of a transfer layer and an adhesive layer formed by curing a transfer composition containing a photopolymerization initiator having a mass reduction rate of more than 4%, while there is no peeling from the substrate with the recording layer (Comparative Example 5) Was found to be peeled off from the substrate with the recording layer.

In addition, the symbol in Tables 1-4 is as follows.
D-330: A polymerizable compound modified with an average of 3 ethyloyl groups and an average of 3 acryloyl groups per molecule with respect to dipentaerythritol [in the formula (1), R ¹ is an acryloyl group, R ² is an ethyloyl group, a = 3, b = 3] (Nippon Kayaku Co., Ltd., trade name: KAYARAD D-330)
HPN: hydroxypivalic acid neopentyl glycol ester diacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name: Diabeam UK-4101)
PM-21: Ethylene oxide modified phosphate acrylate (manufactured by Nippon Kayaku Co., Ltd., trade name: KAYAMER PM-21)
Irg. 127: 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one (manufactured by Ciba Japan Co., Ltd.) , Product name: IRGACURE 127)
Irg. 2959: 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (manufactured by Ciba Japan Co., Ltd., trade name: IRGACURE 2959)
Irg. 907: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (manufactured by Ciba Japan Co., Ltd., trade name: IRGACURE 907)
DAROCUR TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by Ciba Japan Co., Ltd., trade name: DAROCUR TPO)
Irg. 651: 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by Ciba Japan KK, trade name: IRGACURE 651)
Irg. 184: 1-hydroxy-cyclohexyl phenyl ketone (manufactured by Ciba Japan Co., Ltd., trade name: IRGACURE 184)
DAROCUR 1173: 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by Ciba Japan KK, trade name: DAROCUR 1173)

Claims (3)

  ACTIVITY FOR INTERLAY LAYER OF MULTILAYER STRUCTURE OPTICAL INFORMATION MEDIUM FOR FORMING INTERMEDIATE LAYER OF MULTILAYER STRUCTURE OPTICAL INFORMATION MEDIUM HAVING AT LEAST TWO INFORMATION RECORDING LAYERS AND TWO INTERMEDIATE INFORMATION RECORDING LAYERS An energy ray curable composition comprising a polymerizable compound and a photopolymerization initiator having a mass reduction rate of 4% or less when held at 110 ° C. for 1 hour.   The photopolymerization initiator is 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one or 1- [4 The active energy ray-curable composition for an intermediate layer of an optical information medium having a multilayer structure according to claim 1, which is-(2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one. .   A multilayer structure optical information medium having at least two information recording layers and an intermediate layer having a thickness of 3 to 30 μm between two adjacent information recording layers, wherein a part or all of the intermediate layer is defined in claim 1 or 2. A multilayer optical information medium which is a cured product of the active energy ray-curable composition for an intermediate layer of the multilayer optical information medium described above.