JPH03219476A - Information recording medium - Google Patents

Abstract

PURPOSE:To facilitate mounting and to increase strength of adhesion by constituting an adhesive to be used between the outer peripheral surfaces of the insertion parts of hubs and disk substrates, etc., of a compsn. contg. a specific compd. and org. peroxide. CONSTITUTION:Adhesive layers are formed in notches 13 formed in the outer peripheral parts of the hubs 4, between the inner peripheral surfaces in the center holes 3 of the disk substrates 2a, 2b and the outer peripheral surfaces of the insertion parts 8 of the hubs 4 and between the hubs 4. The adhesive to form the adhesive layer is constituted of the active energy ray curing type compsn. contg. the compd. selected from the group consisting of an epoxy resin, sulfonium salt and cyclopentadienyl iron compd., the compd. selected from the group consisting of acrylate, methacrylate and the oligomers thereof and the org. peroxide. The information recording medium 1 with which the operation to mount the medium is easy and the high strength of adhesion is obtainable and which has the sticking structure is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording medium used, for example, as an optical disc.

[Conventional technology]

Plastic information recording media, in which information is written and read by focusing light such as a laser beam onto a recording layer, are required to withstand use under harsh conditions due to long-term temperature and humidity cycles. There is. To meet this demand, we created a cured resin (
Information recording medium reinforced by forming an adhesive layer
9-175046). However, although such information recording media are effective against temperature and humidity cycles, they are weak against driving force from the inner periphery, so there is a problem that they tend to peel off from the inner periphery.

Therefore, there is an information recording medium (Japanese Unexamined Patent Publication No. 119747/1989) in which a cage-shaped connecting rod is inserted into a circular hole around the center hole, and metal suction plates are attached above and below the connecting rod, but the structure is It is complicated and requires drilling holes in the disk substrate during installation, which poses problems such as difficult installation work.

On the other hand, one of the adhesives used for laminating these information recording media is an active energy beam-curable epoxy resin composition. However, many of these have poor adhesion in the early stage of curing, and also have a relatively long curing time, so they have the disadvantage that, for example, the speed of the production line for optical tissues cannot be increased. Moreover, many of them also have a problem of being inferior in moisture-resistant adhesion.

[Problem to be solved by the invention]

The object of the present invention is to solve the above-mentioned problems by having a laminated structure that is easy to install, has a high adhesive strength, cures extremely quickly, and has excellent adhesive properties and moisture-resistant adhesive properties in the initial stage of curing. The objective is to provide an information recording medium with excellent performance.

[Means to solve the problem]

The present invention comprises two disk substrates each having a recording layer formed on one side of at least one transparent resin substrate and bonded together with the recording layer inside, and an inserter inserted into a center hole of the disk substrate. and a flange portion covering the disk substrate near the center hole, and two hubs that are attached to the center hole from both sides, a notch formed on the outer periphery of the hub, and within the notch, An adhesive layer is formed between the inner peripheral surface of the center hole of the disk substrate and the outer peripheral surface of the hub insertion part and between the two hubs, and the adhesive forming this adhesive layer is (A) epoxy resin. , (B) a compound selected from the group consisting of sulfonium salts and cyclopentadienyl iron compounds, (C) a compound selected from the group consisting of acrylates, methacrylate-1- and oligomers thereof, and (D) an organic peroxide. An information recording medium comprising an active energy beam-curable composition containing:

In the present invention, two disk substrates are bonded together with the recording layer inside, but they may be bonded directly or may be bonded via an outer spacer and an inner spacer. As a means for bonding, an active energy ray-curable composition that is cured by irradiation with active energy rays is used as an adhesive.

The transparent resin substrate, outer spacer, and
As the material for forming the inner circumferential spacer and the hub, thermoplastic resins such as polycarbonate, polymethyl methacrylate, and non-grade polyolefin can be used. Preferred resins for forming the transparent resin substrate include a cyclic olefin random copolymer (a) consisting of a copolymer of ethylene and a cyclic olefin represented by the following formula [1]; There is a ring-opening polymer of a cyclic olefin component represented by 1] or its hydrogenated product (b).

In the cyclic olefin random copolymer (a), the cyclic olefin represented by the general formula [1] above mainly forms repeating units having a structure represented by the following general formula [1-a].

(In the formula, R1-R12 are a hydrogen atom, a hydrocarbon group, or a halogen atom, and each may be the same or different. Also, R9 and RIG, or R11 and R12 are combined to form a divalent hydrocarbon group. R9 or RIO and R11 or R12 may mutually form a ring. n is 0 or a positive integer.

When R5-R8 are repeated multiple times, they may be the same or different. ) The cyclic olefin as a component of the above-mentioned cyclic olefin-based random copolymer (a) is at least one cyclic olefin selected from the group consisting of unsaturated monomers represented by the above general formula [1]. .

(In the formula, n and R1-R12 are the same as in the above general formula [1].) R1 to H12 in the above general formula [1] are hydrogen atoms,
An atom or group selected from the group consisting of a halogen atom and a hydrocarbon group.

Examples of R1 to RI' in the general formula [1] include hydrogen atoms; halogen atoms such as fluorine, chlorine, and bromine; and lower alkyl groups such as methyl, ethyl, propyl, and butyl groups. They may be different, partially different, or entirely the same.

Examples of 89 to R12 in the general formula [1] include a hydrogen atom; a halogen atom such as fluorine, chlorine, and bromine; a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a hexyl group, and a stearyl group. Alkyl groups such as; cycloalkyl groups such as cyclohexyl; substituted or unsubstituted aromatic hydrocarbon groups such as phenyl, tolyl, ethylphenyl, isopropylphenyl, naphthyl, anthryl; benzyl, phenethyl groups; , and an aralkyl group in which the alkyl group is substituted with an aryl group, and these may be different from each other or all may be the same.

Further, R9 and R″0, or RIi and R12 may be combined to form a divalent hydrocarbon group, and R9 or Rx
o and RIi or P2 may mutually form a ring 1
Examples of the divalent hydrocarbon group formed by combining Rg and Rxa or R11 and R''2 include alkylidene groups such as ethylidene, propylidene, and isopropylidene groups.

The ring formed from Rg or Rho and RLl or R1,2 may be monocyclic or polycyclic, may be a polycyclic ring having a bridge, or may be a ring having a double bond, Alternatively, a ring consisting of a combination of these rings may be used.

Specific examples of such a ring include the following. These rings may have a substituent such as a methyl group. In the above chemical formula, the carbon atom marked with 1 or 2 represents the carbon atom to which R9 to R12 are bonded in the general formula [1].

The cyclic olefin represented by the general formula [1] can be easily produced by condensing a cyclopentadiene and a corresponding olefin or cyclic olefin by a Diels-Alder reaction.

Examples of the cyclic olefin represented by the general formula [1] include bicyclo(2,2,1)hept-2-ene or its derivatives, tetracyclo[4,4,0,12.51
"10.l-3-dodecene or its derivative, hexacyclo(6,6,1,1"",1111+13.0"
+7.0'l") -4-hebutadecene or its derivatives, octacyclo[8,8,0°12 + 9,1
4 + 7, 111 + 1.6, 11311G
, 0'' + ', P 2 * 17) -5,,
, F-11cene or its derivatives, pentacyclo[6
,6,1゜13 ,G ,Q2.7 *09,14)
-4-hexadecene or its derivative, pentacyclo(
6,5,1,13+6.0" 17.0I1113)-
4-pentadecene or its derivatives, heptacyclo[8
゜7.0.12・9.14・7, 111 + 17
, 03 + [1,Q 1211G ] −]5-eicose or its derivative, heptacyclo[8,8,0,1
21g14+7.111+iS, Q3+11. Q12+
171-5-heneicosene or its derivatives, tricyclo[4,3,0,12.5]-3-decene or its derivatives, tricyclo(4,4,0,12'']-]3-
Undese or its derivatives, pentacyclo[6,5,1
,13.'',0''+7.0''13] -4,10-pentadecadiene or its derivative, pentacyclo[6,5
,1,]3·60217.09113]-4,11-pentadecadiene or its derivatives, pentacyclo(4,
7,0,12+5.01′”, 19・12)-3-pentadecene or its derivatives, pentacyclo(4,7,0
, 1"Is, Oe", 19+123-3.10-hen'il tekaxin or its derivative, heptacyclo(7,8,0,1"I'Q2,7.110,1'1.
Qllll, 6.11. Z・1=) -4-eicosene or its derivative, nonacyclo(9,10,], 141
”, 03I802・1G, Q12.21, 113
．． Examples include 20.014.19.11S.18)-s-bentacocene or its derivatives.

Further, examples of the cyclic olefin represented by the general formula [1] include compounds represented by the following general formula [2].

(In the formula, p is O or an integer of 1 or more, q and r are Ol
l or 2, R1-R4 and R1,Q + R'2
represents the same as the general formula [1], and R1,3 to R2
1 each independently represents an atom or group selected from the group consisting of a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and an alkoxy group, and pH~R12 and H13~B21 are directly or They may be bonded via one to three alkylene groups to form a ring. ) Specific examples of R1.3 to R21 in the general formula [2] include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine, or bromine; a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, Isobutyl group, hexyl group,
Aliphatic hydrocarbon groups such as stearyl groups; cycloalkyl groups such as cyclohexyl groups = substituted or unsubstituted aromatic hydrocarbon groups such as phenyl groups, tolyl groups, ethylphenyl groups, isopropylphenyl groups, naphthyl groups, anthryl groups;
Examples include aralkyl groups such as benzyl group and phenethyl group; alkoxy groups such as methoxy group, ethoxy group, and propoxy group; these may be different from each other, or may be partially different, or all may be the same. It may be.

In the compound represented by the general formula [2], p is O
-3 are preferred.

Specific examples of the compound represented by the general formula [1] include those listed in Table 1.

Table = 15 = Table (continued 2) Table (1) Table (3) Table (4) Table (6) Table (5) 20- Table (7) Table ( Continued 8) Table (Continued 10) Table (Continued 9) Table (Continued 11) Table (Continued 12) Table (Continued 14) 129 = Table (Continued 13) Table (Continued 15) Table 1 (Continued 16) ) The cyclic olefin-based random copolymer (a) has the above-mentioned cyclic olefin component and ethylene component as essential components, but in addition to these two essential components, any necessary components may be added to the extent that the purpose of the present invention is not impaired. Depending on the situation, other copolymerizable unsaturated monomer components may be contained. Examples of unsaturated monomers that may optionally be copolymerized include those having 3 carbon atoms,
-20 alpha olefins, hydrocarbon monomers containing two or more carbon-carbon double bonds in one molecule, and the like. Specifically, the α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 1-pentene, 4-
Methyl-1-pentene, 3-methyl-1-pentene, 1
hexene, 1-heptene, l-octene, 1-nonene,
Examples include 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and -eicosene. Examples of hydrocarbon monomers containing two or more carbon-carbon double bonds in one molecule include 1,4-hexadiene, 1,6-octadiene, and 2-methyl-1,5- xadiene, 4-methyl-1,5-hexadiene, 5-methyl-1,5-hexadiene, 6-
Methyl-1,5-hebutadiene, 7-methyl-1,6-
Chain nonconjugated dienes such as octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-
2-norbornene, 5-methylene-2-norbornene,
5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, 4,
9゜5.8-dimethano-3a, 4,4a, 5,8,8a
, 9,9a-octahydro-1H-benzoindene and other cyclic non-conjugated dienes: 2゜3-diisopropyritine-5-
Examples include norbornene; 2-ethylidene-3-isopropylidene-5-norbornene; and 2-propenyl-2,2-norbornadiene. Among these, 1,4-hexadiene, 1,6-octadiene,
and cyclic non-conjugated dienes, especially dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-
2-norbornene, 5-methylene-2-norbornene,
1,4-hexadiene and 1,6-octadiene are preferred.

In the cyclic olefin random copolymer (a), the structural units derived from the ethylene component range from 40 to 85 mol%, preferably from 50 to 75 mol%, and the structural units derived from the cyclic olefin component range from 15 to 60 mol%. , preferably 2
A range of 5 to 50 mol % is appropriate, and the structural units derived from the ethylene component and the structural units derived from the cyclic olefin component form a substantially linear cyclic olefin random copolymer arranged randomly. The fact that the cyclic olefin random copolymer (a) is substantially linear and does not have a gel-like crosslinked structure means that this copolymer has 1
This can be confirmed by complete dissolution in decalin at 35°C.

135°C of cyclic olefin random copolymer (a)
The intrinsic viscosity [η] measured in decalin is 0. O1~1
0 clQ/g, preferably in the range of 0.05 to 5 dQ/g.

Further, the cyclic olefin random copolymer (a) has a softening temperature (TMA) of 70°C or higher, preferably 90 to 25°C, as measured by a thermal mechanical analyzer.
0°C, more preferably 100 to 200°C, glass transition temperature (Tg) usually 50 to 230°C, preferably 70°C
~210°C, the degree of crystallinity measured by X-ray diffraction is 0-10%, preferably 0-7%, particularly preferably 0-7%.
A range of 5% is preferred.

As the cyclic olefin random copolymer (a), one type of copolymer having physical properties within the above range may be used, but the intrinsic viscosity measured in decalin at 135°C [η
] is in the range of 0.05 to 10 dQ/g, and the softening temperature (TMA) is 70°C or higher, preferably 90 to 250°C
100 parts by weight of a cyclic olefin random copolymer has an intrinsic viscosity [η] measured in decalin at 135°C in the range of 0.01 to 5 dQ/g, and a softening temperature (T
It is also possible to use a composition blended with 0.1 to 10 parts by weight of a cyclic olefin random copolymer having a MA) of less than 70°C, preferably -10 to 60°C.

The cyclic olefin random copolymer (a) comprises an ethylene component, a cyclic olefin component represented by the general formula [1], and other monomer components copolymerized if necessary.
It can be produced by polymerization in the presence of a well-known Ziegler catalyst.

Examples of the Ziegler catalyst include (a) a catalyst comprising a composite containing at least magnesium, titanium, and halogen and an organoaluminum compound;
Examples include catalysts consisting of vanadium compounds and organoaluminum compounds. Of these, the latter (
The catalyst a) is preferred, and a catalyst comprising a soluble vanadium compound and an organoaluminum compound is particularly preferred.

A specific method for producing the cyclic olefin random copolymer (a) is described in JP-A-60-168708 and JP-A-6
1-120816, JP-A-61-115912, JP-A-61-115916, JP-A-61-
271.308, JP 61-272216, JP 62-252406, JP 62-2
This method is disclosed in Japanese Patent No. 52407 and the like.

In addition to the cyclic olefin random copolymer (a), preferred resins for the transparent resin substrate for forming the disk substrate include 1 selected from the cyclic olefins represented by the general formula [1] above. A ring-opening polymer consisting of more than one type of cyclic olefin component or its hydrogenated product (b
) (hereinafter referred to as a cyclic olefin ring-opening polymer) can also be used. Such a cyclic olefin-based ring-opening polymer is disclosed, for example, in JP-A-60-26024.

The cyclic olefin constituting the cyclic olefin-based ring-opening polymer (b) is at least one cyclic olefin selected from the group consisting of unsaturated monomers represented by the above general formula [1].

In the ring-opening polymer before hydrogenation of the hydrogenated cyclic olefin-based ring-opening polymer, the cyclic olefin component represented by the general formula [1] is represented by the following general formula (1-b).
In the ring-opened polymer after hydrogenation, the following general formula (1-
It mainly forms repeating units with a structure represented by c].

(In the formula, n and R1-R12 are the same as in the above general formula [1].) The cyclic olefin-based ring-opening polymer (b) has the above-mentioned cyclic olefin as an essential component, but If necessary, other copolymerizable unsaturated monomer components may be contained within a range that does not impair the purpose. Examples of the optionally copolymerized unsaturated monomer include the following general formula [
Examples include cyclic olefins represented by [3].

(In the formula, R22 and RZ3 are hydrogen atoms, hydrocarbon groups, or halogen atoms, and may be the same or different, respectively. R is an integer of 2 or more, and when R'''R23 is repeated multiple times (These may be the same or different, respectively.) Examples of the monomer component represented by the general formula [3] include cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclononene, cyclodecene, methylcyclopentene, and methylcycloheptene. , methylcyclooctene, methylcyclononene, methylcyclodecene, ethylcyclopentene, ethylcycloheptene, ethylcyclooctene, ethylcyclononene, ethylcyclodecene, dimethylcyclopentene, dimethylcycloheptene, dimethylcyclooctene,
Examples include trimethylcyclodecene.

Furthermore, examples of monomer components other than the cyclic olefin represented by the general formula [3] include cyclooctadiene and cyclodecadiene.

The intrinsic viscosity [η] of the cyclic olefin ring-opening polymer (b) measured in decalin at 135°C is 0.01 to 10 dQ/
g, preferably 0.05 to 5 dQ/g.

Furthermore, as the cyclic olefin ring-opening polymer (b),
Softening temperature (TMA) is 70°C or higher, preferably 90-2
00℃, crystallinity measured by X-ray diffraction method is 0~
10%, preferably 0-7%, particularly preferably 0-5%
Preferably.

As the cyclic olefin ring-opening polymer (b), a polymer consisting only of those having physical properties within the above range may be used, but a polymer having physical properties outside the above range may be partially included. In this case, it is sufficient that the entire physical property value is within the above range.

In order to produce a ring-opening polymer of a cyclic olefin component represented by the general formula [1] above, a monomer component selected from the general formula [1] above is used as a raw material, and the ring-opening polymer is subjected to ring-opening polymerization using a conventional ring-opening polymerization method for cyclic olefins. Can be polymerized. In this case, examples of the polymerization catalyst include ruthenium, rhodium,
A system consisting of a halide such as palladium, osmium, iridium, platinum, molybdenum, tungsten, nitrate or acetylacetone compound and a reducing agent such as an organic tin compound or alcohol, or a halide such as titanium, vanadium, zirconium, tungsten, molybdenum or acetylacetone A system consisting of a compound and an organic aluminum or the like can be used.

The molecular weight of the ring-opening polymer produced can be adjusted by adding an olefin or the like during ring-opening polymerization.

When hydrogenating the ring-opened polymer obtained above, a conventional hydrogenation method can be used.

As the hydrogenation catalyst, those used in the hydrogenation of olefin compounds can generally be used. Specifically, the heterogeneous catalysts include nickel, palladium,
Solid catalysts include platinum, or these metals supported on carriers such as carbon, silica, diatomaceous earth, alumina, titanium oxide, etc.1 For example, nickel/silica, nickel/diatomaceous earth, palladium/carbon, palladium/silica, Examples include palladium/diatomaceous earth and palladium/alumina. In addition, homogeneous catalysts include those based on metals from group Ⅰ of the periodic table, such as nickel naphthenate/triethylaluminum, cobalt octenoate/n-butyllithium, nickel acetylacetonate/1-ethyl Examples include those made of Ni and Co compounds such as aluminum and organometallic compounds of metals from Groups 1 to 1 of the periodic table, or Rh compounds.

The hydrogenation reaction of the ring-opening polymer is carried out in a homogeneous or heterogeneous system depending on the type of catalyst under a hydrogen pressure of 1 to 150 atm at a temperature of 0 to 180°C, preferably 20 to 100°C. It will be held in The hydrogenation rate can be adjusted by adjusting the hydrogen pressure, reaction temperature, reaction time, catalyst concentration, etc., but in order for the hydrogenated compound to exhibit excellent heat deterioration resistance and light deterioration resistance, it is necessary to It is preferable that 50% or more of the heavy bonds are hydrogenated, preferably 80% or more, and even more preferably 90% or more.

These resins can be used alone or in combination of two or more.

Further, by molding these resins by a general method such as injection molding, it is possible to obtain a molded article such as a transparent resin substrate or a hub in a desired shape.

Further, the recording layer for forming the disk substrate is made of a low melting point metal material such as Te, or Te-C], Te-Cr
, a recording material mainly composed of a low melting point metal material such as a Te-Cr-C-■ film, or a heat mode recording material suitable for the information recording medium of the present invention, such as an organic dye material, or a Tb
- Magneto-optical recording materials containing rare earth elements and 3D transition metals, such as Fe-co, Tb-Fe-co plus pt or Pd, and optionally above and/or below these recording material layers. Any material suitable for the information recording medium of the present invention may be used, such as one composed of a base layer, an antireflection layer, a reflective layer, an interference layer, a protective layer, an enhancement layer, etc. to be laminated.

As the hub, for example, a material made of polycarbonate resin, the above-mentioned cyclic olefin random copolymer (a), or cyclic olefin ring-opening polymer (b) can be used, but if necessary, These resins are attached with magnetic metal, or molded products made of polycarbonate resin, cyclic olefin random copolymer (a), cyclic olefin ring-opening polymer (b), etc. mixed with magnetic material. things can be used. In the present invention, it is particularly preferable to use polycarbonate resin as the hub.

The hub has an insertion portion that is inserted into the center hole of the disk substrate, a flange portion that covers the disk substrate near the center hole, and a notch formed on the outer periphery of the insertion portion. Preferably, the notch is formed on the outer periphery of the distal end of the insertion portion.

The adhesive used in the present invention contains the active energy ray-curable composition that can be cured and bonded by irradiation with active energy rays such as ultraviolet rays.

The epoxy resin (A) contained in the composition used as the adhesive of the present invention is preferably a compound containing two or more epoxy groups in one molecule, such as an aliphatic or alicyclic epoxy compound. is particularly preferred. Such epoxy resins (A) include, for example, glycidyl ether-based epoxy resins of polyphenol compounds such as bisphenol A, bisphenol F, and 1,1,2,2-te1-lakis(4'-hydroxyphenyl)ethane; Glycidyl ether-based epoxy resin of polyhydric phenols such as catechol, resorcinol, hydroquinone, and fluorocurcin; Glycidyl ether-based epoxy resin of polyhydric alcohols such as ethylene glycol, butanediol, chrycerol, erythritol, and polyoxyalkylene glycol; novolac type Epoxy resin; Cycloaliphatic epoxy resin such as vinyl cyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide; polyester condensate of polycarboxylic acids such as phthalic acid and cyclohexane-1,2-dicarboxylic acid Examples include glycidyl ester epoxy resin; polyglycidylamine epoxy resin. Among these epoxy resins, glycidyl ether-based epoxy resins of polyphenol compounds or novolak-type epoxy resins are preferred, and among them, glycidyl ether-based epoxy resins of bisphenol A or bisphenol F are more preferred, particularly glycidyl ether-based epoxy resins of bisphenol A. is particularly preferred.

Further, among the sulfonium salts or cyclopentadienyl iron compounds (B) contained in the composition used as the adhesive of the present invention, as the sulfonium salt, triarylsulfonium salts are preferable, and triphenylsulfonium salts are particularly preferable. preferable. The anion of such a sulfonium salt is preferably, for example, AsF6- or BF4-.

Specific examples include triphenylsulfonium salts, tri(4-methylphenyl)sulfonium salts, and tri(4-methoxyphenyl)sulfonium salts.

Cyclopentadienyl iron compounds include compounds containing two cyclopentadienyl groups in the molecule, or one cyclopentadienyl group and one aromatic group such as a phenyl group or isopropylphenyl group in the molecule. Compounds that contain Among these, the latter compound containing one cyclopentadienyl group and one aromatic group is more preferred, and those containing a cyclopentadienyl group and an isopropylphenyl group are particularly preferred b).

Examples of such cyclopentadienyl iron compounds include cyclopentadienyl isopropylphenyl iron (II) salts.

As the compound (B) in the composition used as the adhesive of the present invention, a sulfonium salt and a cyclopentadienyl iron compound can be used alone or in combination. Among these, as compound (B), cyclopentadienyl isopropylphenyl iron (n) salt represented by the above formula is particularly preferable.

In addition, among component (C) contained in the composition used as the adhesive of the present invention, acrylate-1 to methacrylate is a hydroxy compound or di- or more polyhydroxy compound and acrylic acid or methacrylic acid. and esters are used. Such esters include, for example, monovalent aliphatic alcohols having 1 to 20 carbon atoms, alicyclic alcohols having 1 to 30 carbon atoms, and 1 to 2 carbon atoms.
Acrylic acid or methacrylic acid of a hydroxy compound such as a divalent aliphatic alcohol having 0 carbon atoms, a divalent alicyclic alcohol having 1 to 20 carbon atoms, a trivalent aliphatic alcohol having 1 to 2 carbon atoms, and a hydroxyl group-terminated polyester. Examples include esters with acids.

Specific examples of component (C) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate; cyclohexyl acrylate, norbornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, Boronyl acrylate, cyclohexyl methacrylate, the following formula [4] 8-Yen M-L 辷-M-A ... [4] [In the formula, A is an acrylic acid residue, M is a divalent aliphatic or alicyclic Formula alcohol residue, L is a dibasic acid residue, p is a positive number. ] Polyester whose both ends are blocked with acrylic acid represented by the following formula [5] =48- Furthermore, as specific examples of the component (C), the compounds shown in Table 2 can be mentioned.

Some of these acrylate-1- or methacrylate compounds are disclosed in JP-A-61-136529. These acrylates or methacrylates 1 to 1 can also be used as oligomers produced by prepolymerization according to methods known per se.

Among these components (C), a mixture of an alkyl ester of acrylic acid or methacrylic acid, a compound of the above formula [4], and a compound of the above formula [5] is preferred.

[Wherein, B is an acrylic acid residue or a trivalent or higher polyvalent aliphatic or alicyclic alcohol residue, Y is a divalent or higher polybasic acid residue, and q is a positive number. Examples include polyesters represented by the following formula in which both ends and the hydroxyl groups in the chain are blocked with acrylic acid.

Examples of the organic peroxide (D) include benzoyl peroxide, dichlorobenzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, diter
t-Butyl peroxide, 2,5-dimethyl-2,5-
Di(peroxidebenzoate)hexyne-3,1,4
-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(tar)
tert-butylperoxy)hexane-3,2,5-dimethyl-2゜5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl perisobutyrate, tert Examples include -butylperu-5ee-octoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perdiethyl acetate.

Among these are dicumyl peroxide, di-tart
-butylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5
Dialkyl peroxides such as -dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferred.

The composition used for the adhesive in the present invention is the above-mentioned (A
), (B), (C), and (D) are essential components, and 1 to 1 of components (B) are added to 100 parts by weight of component (A).
10 parts by weight, preferably 2 to 5 parts by weight, component (C) 15
~35 parts by weight, preferably 20-30 parts by weight and (D
) component is preferably contained in an amount of 1 to 10 parts by weight, preferably 2 to 5 parts by weight.

Although a photopolymerization initiation aid is not necessarily required in the composition used for the adhesive in the present invention, it is desirable to include it when relatively low-energy active energy rays such as UV are used. Various known photopolymerization initiation aids can be used, such as a decomposition type that decomposes and generates radicals when irradiated with UV or the like, or a hydrogen abstraction type that generates radicals by extracting hydrogen. Specific examples of such photopolymerization initiation aids include benzoin or its ethers such as benzoin, benzoin methyl ether, benzoin ethyl di-60=, benzoin isopropyl ether, and benzoin butyl ether; benzophenone, P-chlorobenzophenone, Benzophenone compounds such as p-methoxybenzophenone; benzyl,
Benzyl compounds such as benzyl dimethyl ketal; 1
- (4-isopropylphenyl)-2-hydroxy-
2-Methyl-1-propanone, 1-phenyl-2-hydroxy-2-methyl-1-propanone, 1-(4-t
Examples include hydroxyalkylphenylketone compounds such as ert-butylphenyl)-2-hydroxy-2-methyl-1-propane.

Furthermore, as a sensitizer, for example, hydrocarbons such as anthracene, naphthalene, chrysene, and phenanthrene; nitro compounds such as p-dinitrobenzene, p-nitroaniline, 1.3.5-trinitrobenzene, and donitrodiphenyl; n-butylamine; , di-n-butylamine, triethylamine, diethylaminoethyl methacrylate,
P-nitroaniline, N-acetyl-4-nitro-1-
Amino compounds such as naphthylamine; phenol, p-nitrophenol, 2,4-dinitrophenol, 2,4
．． 6- Phenolic compounds such as trinitrophenol;
Ketones such as benzaldehyde, 9-anthraaldehyde, acetophenone, benzophenone, dibenzalacetone, benzyl, P+P-diaminobenzophenone, P,p-tetramethyldiaminobenzophenone; anthraquinone, 1,2-benzoanthraquinone, benzoquinone, 1,2 - Quinones such as naphthoquinone and 1,4-naphthoquinone; anthrone, 1,9-benzaanthrone,
6-phenyl-1,9-benzaanthrone, 3-phenyl-1,9-benzaanthrone, 2-keto-3-aza-
Examples include anthrones such as 1,9-benzaanthrone and 3-methyl-1,3-diaza-1,9-benzaanthrone.

Such a composition used for the adhesive in the present invention may basically be solvent-free, but a solvent may be added, and it may also contain a reactive diluent, a thickener, an anti-sagging agent, a storage stabilizer, Components such as plasticizers that are included in ordinary solvent-free adhesives may also be included.

The information recording medium of the present invention is arranged such that the space between the inner circumferential surface of the center hole of the disk substrate made of the above-mentioned material and the outer circumferential surface of the insertion portion of the hub, within the notch of the hub, and between the two hubs is as described above. It is attached using an adhesive such as

In the present invention, the information recording medium includes all media in which information is recorded in a recording layer, such as an optical disc and a flexible optical disc.

[For production]

In the information recording medium of the present invention, a disk substrate having a recording layer formed on one side of a transparent resin substrate is welded by adhesive or ultrasonic welding directly or through an outer circumferential spacer and an inner circumferential spacer so that the recording layer is on the inside. etc., insert the insertion part of the hub into the center hole from both sides and attach it, between the outer peripheral surface of the insertion part and the inner peripheral surface of the center hole, inside the notch of the hub,
The adhesive made of the above composition is filled between the insertion parts, and the adhesive is bonded by irradiating active energy rays such as ultraviolet rays.

In the information recording medium manufactured in this way, the hub is in contact with the disk substrate through the insertion portion and the flange portion, and the outer peripheral surface of the insertion portion of the hub and the inner peripheral surface of the center hole of each disk substrate are bonded with the above adhesive. in a state where
Since the hubs are bonded together using the adhesive, the entire structure is integrated through the hubs, thereby reinforcing the inner peripheral portion of the center hole and increasing the bonding strength. Furthermore, since the adhesive is cured while being filled in the notch formed in the hub, the peel resistance of the adhesive is increased.

Furthermore, because a specific adhesive is used, it cures extremely quickly and has excellent adhesiveness and moisture-resistant adhesiveness in the initial stage of curing.

〔Example〕 Hereinafter, the present invention will be explained with reference to embodiments of the drawings.

FIGS. 1 and 2 are cross-sectional views showing information recording media according to different embodiments, respectively. In the figure, 1 is an information recording medium, and a recording layer IC1 is formed on one side of transparent resin substrates 1a and 1b.
The two disk substrates 2a and 2b forming the disk substrate 1d are bonded together with the recording layers 1c and 1d facing inside, and the hub 4 is attached to the center hole 3 of the two disk substrates 2a and 2b. ing. The disk substrates 2a and 2b are the first
In the figure, they are stacked with an outer circumferential spacer 5 and an inner open circumferential spacer 6 in between, and are bonded together by ultrasonic welding to form an air sandwich structure, whereas in FIG. 2, they are bonded directly with an adhesive layer 7. The hub 4 has a metal plate 11 attached to a hub body 10 having an insertion portion 8 and a flange portion 9, and has a hole 12 in the center. The metal plate 11 is fixed to the hub body 10 by a cut-and-raised piece and is driven mechanically or magnetically, but detailed illustration is omitted. The insertion portion 8 of the hub 4 is inserted into the center hole 3, and the flange portion 9 covers the disk substrates 2a, 2b near the center hole 3. Furthermore, a notch 13 is formed on the outer periphery of the distal end of the insertion portion 8 to improve the retention of the adhesive. The shape of the notch 13 is such that a small diameter part is provided at the tip of the insertion part 8, but there are other shapes such as those shown in FIGS. An easy-to-use shape can be selected as appropriate. The shape of the notch 13 is preferably as shown in FIG. 1 and FIG. 3(a). In the information recording medium 1 shown in FIGS. 1 and 2, an adhesive layer 14 is formed between the insertion portion 8 and the disk substrates 2a and 2b, between the insertion portions 8 of the two hubs 4, and in the notch 13. Each is fixed and integrated.

As shown in FIGS. 1 and 2, the information recording medium 1 configured as described above is provided by directly attaching the disk substrates 2a and 2b to each other using the outer circumferential spacer 5 and the inner circumferential spacer so that the recording layers 1c and 1d are on the inside. The hub 4 is attached by inserting the insertion part 8 of the hub 4 into the center hole 3 from both sides through the adhesive layer 7 or ultrasonic welding, and the hub The adhesive layer 14 made of the composition of the components (A) to (D) is filled into the eight insertion portions and the notch 13 of No. 4, and the adhesive layer 14 is bonded by irradiating ultraviolet rays.

In the thus manufactured information recording medium 1, the hub 4 is connected to the disk substrates 2a, 2b by the insertion portion 8 and the flange portion 9.
is in contact with the insertion section 8 and each disk substrate 2a.
, 2b and between the hubs 4 are bonded by the adhesive layer 14, so that the entire structure is fixed via the hub 4, thereby reinforcing the inner peripheral portion and increasing the bonding strength.

Further, since the adhesive is cured with the adhesive filled in the notch 13, the peel resistance strength of the adhesive is increased.

Furthermore, since the above-mentioned active energy beam-curable composition is used as the adhesive, the bonded portion cures quickly and has excellent adhesiveness and moisture-resistant adhesiveness in the initial stage of curing.

Test examples will be explained below.

The evaluation of the test example was determined by determining the hub adhesive strength before and after a humidity test in which the information recording medium 1 was placed in a constant temperature and humidity chamber at a temperature of 70° C. and a humidity of 85% for 200 hours.

The hub adhesive strength (bub-bub and/or hub-disk adhesive strength) was determined as follows.

Measuring device: Universal material testing machine (Intesco 205) Measuring method: Attach the hub play I to the hub of the information recording medium, insert the pin into the hole in the hub, press it against the hub plate, and move the pin at a constant speed (20 mm/ Find the maximum stress when pressing down with m1n).

Unit: kgf Test Example 1 As the transparent resin substrates 1a, 1b and the hub body 10,
"The ethylene component measured by C-NMR analysis is 59 mol%.
, the intrinsic viscosity [η] measured in decalin at 135°C is 0.
Ethylene and polycyclic olefin tetracyclo (4,4,0
,1"I'17°10)-a-dodecene (structural formula,
A random copolymer (hereinafter abbreviated as TCD) was molded into a desired shape by injection molding. Then, a recording layer 1 is provided on each of the substrates 1a, 1b and the hub body 10.
c, 1d and the metal plate 11, the disk substrate 2a
, 2b and hub 4 were created.

On the other hand, 80% of bisphenol A epoxy resin (manufactured by Mitsui Petrochemical Industries, Ltd., EPOMIKR-140, trademark) was added.
Parts by weight, and acrylic monomers and oligomers (manufactured by Toagosei Chemical Industry Co., Ltd., Aronix, M-5700)
, M-6100, M-6300, M-8030, trademark)
7 parts by weight, 5 parts by weight for M-5700, M-6100, M-6300 and M-8030, respectively.
Cyclopentadienyl isopropylphenyl iron (
II) 2 parts by weight of salt (manufactured by Ciba-Geigy), 0.25 parts by weight of anthracene (manufactured by Wako Hyakuyaku Kogyo Co., Ltd.), cumene hydroperoxide (manufactured by Kayaku Nouri Co., Ltd., 70% product) 3
．． Using an active energy beam-curable composition containing 1 part by weight as an adhesive, ultraviolet rays were irradiated for 15 seconds at an illuminance of 160 mW/a#, and the adhesive layer 14 was bonded to the disk substrate 2a.
, between the hub 4 and the insertion portion 8, between the hub 4 and the notch 13, and bonded without forming between the flange portion 9 of the hub 4 and the disk substrate 2a, thereby creating the information recording medium 1 shown in FIG. Obtained.

The hub adhesion strength of the information recording medium 1 thus obtained was determined by the measuring method described above. The results are shown in Table 3.

Test Examples 2 to 3 Next, polycarbonate (manufactured by Ondai Kasei Co., Ltd., AD-5503, trademark) (Test Example 2) and polymethylpentene (Mitsui Petrochemical Industries, Ltd.) were used as the transparent resin substrates 1a and 1b.
Co., Ltd., TPX RTl, 8, registered trademark) (Test Example 3)
Disk substrates 2a and 2b were prepared using the same method to obtain an information recording medium 1 similar to that in Test Example 1, and the hub adhesive strength was determined.

The results are shown in Table 3.

Test Example 4 “Ethylene content measured by C-NMR: 59 mol%, 1
Intrinsic viscosity [η) measured in decalin at 35°C: 0.42
dQ/g, TMA Copolymer (A) of ethylene and TCD at 154°C, and ethylene content 89 mol%, 1
Intrinsic viscosity measured in decalin at 35°C [η] 0.44d
A copolymer (B) of ethylene and TCD was synthesized at 12/g and TMA at 39°C.

As the transparent resin substrates 1a and 1b, a blend of the above copolymers (A) and (B) ((A)/(B) =
Information recording medium 1 was prepared in the same manner as Test Example 1 except that 100/1.2) was used, and the hub adhesive strength was determined. The results are shown in Table 3.

Comparative Examples 1 to 2 As comparative examples, the same as Test Example 1 except that compositions were used in which acrylic monomers and oligomers were not blended into the adhesive (Comparative Example 1) and cumene hydroperoxide was not blended (Comparative Example 2). I went to The results are shown in Table 3.

Table 3 From the above results, it can be seen that the difference in the hub adhesion strength of the examples of the present invention before and after the moisture resistance test is small, indicating a good value.

〔Effect of the invention〕

According to the present invention, a hub having an insertion portion, a notch, and a flange portion is attached to a center hole of a disk substrate, and between the outer circumferential surface of the insertion portion of the hub and the inner circumferential surface of the center hole of the disk substrate, inside the notch, and Since an adhesive layer is formed between the hubs using a specific active energy beam-curable composition as an adhesive, the simple bonding structure not only strengthens the bonded area on the inner circumference of the disk substrate, but also facilitates the installation process. This has the effect of providing an information recording medium that cures extremely quickly, has excellent adhesiveness and moisture-resistant adhesiveness in the initial stage of curing, and has high adhesive strength.

[Brief explanation of drawings]

1 and 2 are sectional views of different embodiments, and FIGS. 3(a) to 3(e) are sectional views of the hub. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is an information recording medium, 2a, 2b are disk substrates, 3 is a center hole, 4 is a hub, 5 is an outer spacer, 6 is an inner spacer,
7.14 is the adhesive layer, 8 is the insertion part, 9 is the flange part, 1
0 is a hub body, and 13 is a notch. Agent Patent Attorney Sei Yanagihara Figure 3 (a) (C) (e) (b) (d)

Claims (3)

[Claims] (1) A recording layer is formed on one side of at least one transparent resin substrate, and the two are bonded together with the recording layer inside.
A disc board, an insertion part that is inserted into the center hole of the disc board, and two hubs that have a flange part that covers the disc board near the center hole and are attached to the center hole from both sides. A notch formed on the outer circumference of the hub, and an adhesive layer formed within the notch, between the inner circumferential surface of the center hole of the disk substrate, the outer circumferential surface of the hub insertion part, and between the two hubs. The adhesive forming the adhesive layer is (A) an epoxy resin, (B) a compound selected from the group consisting of sulfonium salts and cyclopentadienyl iron compounds, (C) acrylates, methacrylates, and oligomers thereof. 1. An information recording medium comprising an active energy ray-curable composition containing a compound selected from the group consisting of: and (D) an organic peroxide. (2) The information recording medium according to claim 1, wherein the information recording medium is an optical information recording medium. (3) The transparent resin substrate and/or hub have an intrinsic viscosity [η] of 0.01 to 10 when measured in decalin at 135°C.
dl/g (a) A cyclic olefin random copolymer consisting of an ethylene component and a cyclic olefin component represented by the following general formula [1], or (b) a cyclic olefin represented by the following general formula [1] 3. The information recording medium according to claim 1 or 2, which comprises a ring-opened polymer or a hydrogenated product thereof. ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [1] (In the formula, R^1 to R^1^2 are hydrogen atoms, hydrocarbon groups, or halogen atoms, and may be the same or different. Good. Also R^9 and R^1^0, or R^1^
1 and R^1^2 may be combined to form a divalent hydrocarbon group, and R^9 or R^1^0 and R^1^1 or R^1^2 may form a ring with each other. may be formed. n is 0 or a positive integer, and when R^5 to R^8 are repeated multiple times, they may be the same or different. )