DD297272A5 - INFORMATION RECORDING MEDIUM AND ADHESIVE COMPOSITION - Google Patents

Abstract

There is disclosed an information recording medium formed by adhering two disc substrates with an adhesive composition, at least one of the two disc substrates having a recording layer on at least one surface of a transparent resin substrate thereof, and the adhesive composition has the following components (A) to (i).

Description

For this 2 pages drawings

The present invention relates to an information recording medium and an adhesive composition therefor. More particularly, it relates to an information recording medium used as an optical disk and the like, and more particularly to an information recording medium prepared by adhering two disk substrates together, and an adhesive composition therefor.

As one of plastic information recording media in which information is written and read by focusing laser beams, etc., there is a so-called sandwich type air disk, which is formed by adhering two disk substrates to each other via a spacer in a ring shape.

Also available are UV curable adhesives, double bond tapes, normal temperature curable adhesives, and hot melt adhesives as adhesives for use in making disks having such an air sandwich structure or other structure formed by directly adhering two disk substrates. In general, UV-curable adhesives and double-sided tapes involve disadvantages of severe deformation such as warping, poor appearance such as cracks and pitting, and low adhesion strength. The double-sided tape also includes the lack of air entrapment between itself and the recording medium layer. While the normal temperature curable adhesive provides good appearance and adhesion, it eliminates the lack of severe deformation, e.g. B. curvature, a.

On the other hand, the hot melt adhesive applied by means of a roller, nozzle, etc. provides good appearance and high adhesion strength. Further, the deformation caused by the hot melt adhesive is small compared with the above adhesives and so on. Therefore, the hot melt adhesive attracts attention and some of it is expected. However, when tested under high temperatures and high humidity (eg, at a temperature of 80 ° C and a humidity of 85%) for a long period of time (eg, 300 hours), there are problems that deviations between the glued together discs and strong deformations occur by warping. In order to prevent deviation and deformation, it is common practice to use a hot melt adhesive of high melt viscosity. In this case, however, there is a problem that the hot melt adhesive becomes too hard at room temperature and shows a decrease in adhesiveness at a temperature below room temperature.

Thus, it is an object of the present invention to provide an information recording medium in which no deviation between the bonded-together disk substrates occurs, which is not much deformed even when exposed to high temperature and high humidity for a long time, and which even has high adhesion strength at a lower temperature than room temperature.

Another object of the present invention is to provide a novel adhesive composition suitable for producing the above information recording medium.

Further, it is another object of the present invention to apply the aforementioned novel adhesive composition of the present invention in the production of information recording media. Further problem solutions and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are firstly achieved by an information recording medium formed by adhering two disc substrates with an adhesive composition, wherein at least one of the two disc substrates has a recording layer on at least one surface of a transparent resin substrate and the adhesive composition has the following components (A) to (D):

(A) a-olefin polymer,

(B) an ethylene / methacrylate copolymer,

(C) a styrene type polymer and

(D) an adhesive

with the proviso that at least one of the components (A) to (D) with an unsaturated carboxylic acid or a

Derivative thereof is modified. Fig. 1 illustrates a cross section of an embodiment of the information recording medium of the present invention. Figs. 2 (a) and 2 (b) are cross-sectional views showing a process step of applying the adhesive composition

schematically represent.

3 (a) and 3 (b) are cross-sectional views schematically illustrating a process step of adhering the disks together

represent.

In the context of the present invention, at least one disk substrate has a structure in which a Recording layer is formed on at least one surface of a transparent resin substrate. There are two

this disc substrates with an adhesive directly or via an annular spacer with the

Recording layers bonded together inside. The transparent resin substrate materials to be used in the production of the disc substrate are transparent

thermoplastic resins of z. As polycarbonates, polymethylmethacrylates, polyolefins and the like. Of these resins are

Polyolefin resins are particularly preferred in terms of adhesion with the adhesive. Examples of the polyolefin resins are:

(a) a copolymer of ethylene with a cycloolefin of the following formula (I)

(D

wherein R ¹ to R ^{8 may be the} same or different and each represents a hydrogen atom, a halogen atom c which is a hydrocarbon group, R ⁹ to R ^{12 may be the} same or different and each represents a hydrogen atom, a halogen atom or a hydrocarbon group or a combination of R ⁹ and R '° or R "and R ^{12 can be} a divalent hydrocarbon group and a combination of R ⁹ or R' ° and R" or R ' ² can form a ring and n is O or a positive integer, with the proviso when η is 2 or more, a plurality of R ⁵ , a plurality of R ⁶ , a plurality of R ^7, or a plurality of R ^{8 may be the} same or different, wherein the copolymer is the cycloolefin of the above formula (I) as a polymer unit of the following formula (Ia)

(L-a)

in which R 'to R' ² and η are as defined for the above formula (I) and the two open lines on the left side of the formula represent bonds, (b) a polymer of a cycloolefin of the above formula (I) or A copolymer of ethylene with a cycloolefin of the above formula (I), wherein the polymer or copolymer comprises the cycloolefin of the above formula (I) as a polymer unit polymerized by a ring-opening polymerization represented by the following formula (Ib)

(L-b)

RV _n

wherein R ¹ to R ¹² and η are as defined in the above formula (I) and the two open lines on the left side of the formula represent bonds, or a hydrogenation product thereof, and (c) a copolymer of ethylene with a polycyclic monomer of the following formula (II)

(CH ₃ ) _p (CH ₃ ) _q

CH _n )

3'fi

(ID

wherein ρ, q, r and s are each 0 or 1 and is 10 or a positive integer, said copolymer comprising the polycyclic monomer of the formula (II) as a polymer unit of the following formula (II-a)

(CH ₃ )

^ CH

3> r

CH ₃ ),

(Ha)

wherein p, q, r, t and s are as defined in the above formula {II).

The above copolymer (a) will first be described in more detail below.

In the above formula (I), R 'to R ^{8 may} each be the same or different and represent a hydrogen atom, a halogen atom or a hydrocarbon group. Examples of Halogona'.oms are fluorine, chlorine and bromine. Examples of

Hydrocarbon group are preferably lower alkyl groups such as methyl, ethyl, propyl and butyl groups.

In the above formula (I), R ⁹ to R ^{12 may} each be the same or different and represent a hydrogen atom, a halogen atom or a hydrocarbon group. Examples of the halogen atom are the above.

Examples of the hydrocarbon group are alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl and stearyl groups, cycloalkyl groups wio a cyclohexyl group and the like. A combination of R ⁹ and R ¹⁰ or R "and R ¹² may form a divalent hydrocarbon group, and R ⁹ or R ¹⁰ and R ¹¹ or R ' ² may form a ring with each other.

Examples of the divalent hydrocarbon group formed from a combination of R ⁹ and R ¹⁰ or R ¹ 'and R' ² are alkylidene groups such as ethylidene, propylidene and isopropylidene groups.

The ring formed by R ⁹ or R ¹⁰ and R "odor R ¹² may be a single ring, a condensed ring, a bridged polycyclic ring or a ring having an unsaturated bond, or it may be a combination of these rings a substituent such as an alkyl group (e.g., methyl group) and the like.

Examples of the compound of the above formula (I) are bicyclo [2.2.1] hept-2-ene

6-methylbicyclo (2.2.1) hept-2-ene, 5,6-dimethylbicyclo (2.2.1) hept-2-ene, 1-methylbicyclo | 2.2.1) hept-2-ene, 6-ethylbicyclo [2.2. 1) hept-2-ene, e-butylbicycloI2.2.1) hept-2-ene, 6-isobutylbicyclo (2.2.1lhept-2-ene, 7-methylbicyclo- | 2.2.1] hept-2-ene, tetracyclo [4.4 .0.1 ²⁶ , 1 ⁷ '° l-3-dodecene

8-methyl tetra [4.4.0.1. ² - ⁶ , 1 ⁷ - ¹⁰ l-3-dodecene, 8-ethyl or 8-propyl-tetracyclo [4.4.0.1 ^2S , 1 ^7l0 | 3-dodecene,

8-hexyltetracyclo- | 4.4.0.1 ²⁵ , 1 ⁷¹⁰ ] -3-dodecene,

8-stearyltetracyclo [4.4.0.1 ²⁵ , 1 ^7l0 ] -3-docecene,

8,9-Dimethyltetracyclo [4.4.0.1} ^6, 1 ⁷ - ¹⁰⁾ -3-dodecene,

8-methyl-9-ethyltetracyclo [4.4.0.1. ²⁵ , 1 ^7l0 ! -3-dodecene,

8-chloro tetracyclo [4.4.0.1 ^25, 1 ^{7 '0)} -3-dodecene, 8-Bromtetracyclo [4.4.0.1 ^26, 1 ^7L0 l-3-dodecene, 8-Fluortetracyclot4.4.0.1 ^25, 1 ^{7' 0)} -3-

dodecene, 8,9-dichlorotetracyclo (4.4.0.1 ²⁶ , 1 ⁷ - ¹⁰ l-3-dodecene, 8-cyclohexyltetracyclo [4.4.0.1 ^2S , 1 ^7l0 j-3-dodecene, 8-

lsobutyltetracylco [4.4.0.1. ^25, 1 ⁷ - ¹⁰ L-3-dodecene,

8-butyltetracyclol4.4.0.1 ² - ⁶ , 1 ⁷¹⁰ l-3-dodecene,

8-ethylidenetracyclo! 4.4.0.1 ² - ⁵ , 1 ⁷ - ¹⁰ l-3-dodecene,

8-ethylidene-9-methyltetracyclo | 4.4.0.1 ^JB , 1 ⁷ - ¹⁰ ] -3-dodecene,

8-ethylidene-9-ethyltetracyclo [4.4.0.1 ^26, 1 ⁷ - '° l-3-dodecene,

8-ethylidene-9-isopropyltetracyclo | 4.4.0.1 ^2S, 1 ^{7 "))} -3-dodecene, 8-ethylidene-9-butylletracyclo [4.4.0.1 ^26, 1 ⁷ - ¹⁰ L-3-dodecene,

8-n-propylidenetracyclo [4.4.0.1 ^2B , 1 ⁷ - ¹⁰ ) -3-dodecene,

8-n-propylidene-9-methyltetracyclo [4.4.0.1 ²⁸ , 1 ⁷ - ¹⁰ ] -3-dodecene,

8-n-propylidene-9-ethyltetracyclo | 4.4.0.1 ² - ⁶ , 1 ⁷¹⁰ l-3-dodecene,

8-n-propylidene-9-isopropyltetracyclo [4.4.0.1 ^28, 1 ⁷ - ¹ ° l-3-dodecene,

8-n-propylidene-9-butyltetracyclo [4.4.0.1 ^2S , 1 ⁷¹⁰ l-3-dodecene, 8-isopropylidenetfacyclo | 4.4.0.1 ²⁶ , 1 ⁷ - ¹⁰ ] -3-dodecene, 8-isopropylidene-9-methyltetracycloI4.4.0. 1 ^26, 1 ⁷ - ¹⁰ | -3-dodecene, 8-isopropylidene-9-ethyltetracycloI4.4.0.l ^26, 1 ⁷ - ¹⁰ | -3-dodecene, 8-isopropylidene-9-isopropyltetracyclo (4.4.0.1 ^i6, 1 ⁷¹⁰ ) -3-dodecene, 8-isopropyl-9-butyl-tetracycloI4.4.0.1 ^{} 6} , 1 ⁷ - ¹⁰ J-3-dodecene,

5,10-Dimethyltetracyclo [4.4.0.1 ^26, 1 ^7L0 | -3-dodecene, 2,10-Dimethyltetracyclo [4.4.0.1 ^26, 1 ⁷ - ¹⁰ | -3-dodecene, 11,12-Dimethyltetracyclo [4.4.0.1 ^2S , 1 ⁷ - ¹⁰ l-3-dodecene, 2,7,9-trimethyltetracyclo [4.4.0.i ", 1 ⁷ - ¹⁰ l -3-dodecene, 9-ethyl-2,7-dimetyltetracyclo 4 4.4.0.1 ²⁶ , ¹⁷¹⁰ | -3-dodecene, 9-isobutyl-2,7-dimethyltetracyclo [4.4.0.1 ^26, 1 ^7L0 l-3-dodecene, 9,11,12-Trimethyltetracyclo (4.4.0.1 ^'e, 1 ^{7 l0} | -3-dodecene, 9-ethyl-11,12-dimethyltetracyclo [4.4.0.1 ^{6, 1710 |?} -3-dodecene, 9-isobutyl-11,12-dimethyltetracyclo | 4.4.0.1 ^{2 6, 1710} | 3-dodecGn, 5,8,9,10-tetramethyltetracyclo [4.4.0.1 ^2S , 1 ⁷¹⁰ 1-3-dodecene;

Hexacyclo [6.6.1.1 ³ ·, 1 ¹⁰ · ¹³ , 0 ² · ⁷ , 0 ⁹ "l-4-heptadecene,

12-methylhexacyclo | 6.6.1.1 ^{3 e} , 1 ¹⁰ⁿ , 0 ^{2 7} , 0 ^{9 u} l-4-heptadecene, 1 ^ ethylhexacyclole.ei. 1 ^3e , 1 ^lon ₍ O ^{2 7} , 0 ^9u ] -4-heptadecene, 12-isobutylhexacyclo | 6.6.1.1 ³ ', 1 ¹⁰¹³ , 0 ² - ⁷ , 0 ^{9 u} | -4-heptadecene, 1,6,10-trimethyl-12-isobutylhexacyclo [6.6.1

heptadene; octacyclo [8.8.0.1 ²⁹ , 1 ⁴⁷ , i " ^le , i ' ^3U , 0 ^3e , 0' ² ' ⁷ ] -5-docoses

³ , 0 ^{2 7} , 0 ⁹

Pentacyclo (6.6.1.1 ^3e, 0 ^27, 0 ⁹ -. ^14] -4-hexadecene, (

-4-hexadecene 1,3-dimethylpentacyclo [6.6.1.1 ^{3 e,} 0 ^{2 7} 0 ^{9 l4),} 1, e-Dimethylpentacycloie.e. 1.1 ^{3 e} , 0 ^{2 7} , 0 ^9l4 ) -4-hexadecene, 15,16-dimethylpentacyclo [6.6.1.1 ^3e , 0 ²⁷ , 0 ^9l4 ] -4-hexadecene; Pentacyclo | 6.5.1.1 ^3e , 0 ² - ⁷ , 0 ⁹ - ¹³ ] -4-pentadecene,

1,3-Dimethyipentacyclo [6.5.1.1 ^3e , 0 ", 0 ⁹ - ¹³ ] -4-pentadecene, 1,6-dimethylpentacyclo [6,5,1,1 ^3e , 0", 0 ⁹ - ¹³ ] -4-pentadecene, 14,15-dimethylpentacyclo [6.5.1.1 ³⁶ , 0 ²⁷ , 0 ⁹ - ' ³ ] -4-pentadecene;

Heptacyclo [8.7.0.1 ²⁹ , 1 ⁴ - ⁷ , i "", 0 ³⁸ , 0 ¹² - ^ie l-5-eicosene Heptacyclo [8.8.0.1 ^{2 9} , 1 ^{4 7} , 1 "x ^1β , 0 ^{3 8} , 0 ^{12 l 7} ] -5-heneicoses,

Tricyclol4.3.0.1. ^{2 5} ) -3-decene

2-methyltricyclo [4.3.0.1 decene ^{J-3 26,} 5-methyltricyclo [4.3.0.1 ^26] -3-decene; tricyclo [4.4.0.1 ² - ⁵ l-3-undecene

10-methyltricyclo [4.4.0.i] | -3-undecene; and pentacyclo | 6.5.1.1 ^3e , 0 ² - ⁷ , 0 ⁹ⁿ l-4.10-pentadecadiene

and cycloolefins of the following formula (Γ)

(I ¹ )

wherein R'-R ⁴ , R ⁹ R and R ^{12 are} as defined in formula I, R ¹⁵ -R "may be the same or different, each of a hydrogen atom may be a halogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group or an alkoxy group and a group of R ⁹ , R ¹¹ and R ¹² and a group of R ' ⁶ -R "may form a ring directly or via alkyl groups having 1-3 carbon atoms; X is 0 or an integer greater than or equal to 1, and Y and ζ are independently 1 or 2.

In the above formula (Γ), R ¹⁵ -R ^{22 may be} different or the same and a hydrogen atom, a halogen atom such as fluorine, chlorine or bromine, an aliphatic hydrocarbon group such as methyl, ethyl, propyl, iso-propyl, butyl , iso-butyl, hexyl or a stearyl group, a cycloalkyl group such as cyclohexyl, an unsubstituted or substituted aromatic hydrocarbon group such as phenyl, ToIyI, ethylphenyl, iso-propylphenyl, naphthyl, anthryl, a Aralkyl group such as benzyl or phenethyl and an alkoxy group such as methoxy, ethoxy or propoxy.

In the above formula (I '), χ is preferably 0, 1, 2 or 3. Examples of the compound of the above formula (I') are 5-methyl-5-phenylbicyclo [2,2,1] hept-2 5-methyl-5-phenylbicyclo- [2,2,1] hept-2-ene, 5-benzylbicyclo [2.2.1 lhept-2-ene, 5-tolylbicyclo [2.2.1] hept-2-ene, 5- (ethylphenyl) bicyclo [2.2.1] hept-2-ene, 5- (a-naphthyl) bicyclo [2.2.1] lhept-2-ene 5- (isopropylphenyl) bicyclo-12.2.1] hept-2 en, 5- (anthracenyl) bicyclo [2.2.1] hept-2-ene, 5- (ethylphenyl) bicyclo [2.2.1] hept-2-ene, cyclopentadienacenaphylene adduct

1,4-methano-1,1n, 4,4n-tetrahydrofluorene

(CC®,

and M-methano-M ^ n.BIO.IOn-hexahydroanthracene

Cycloolefins of formula (I) can be readily prepared by condensing cyclopentadienes and corresponding olefins under a Diels-Alder reaction.

It should be understood that the scope of the cycioolefin of formula (I) above includes a single stereoisomer or a mixture of stereoisomers in any ratio. Mutual conversion between the stereoisomers can be carried out in the presence of an isomerization catalyst.

As described above, the copolymer (a) of a cycloolefin comprises a polymer moiety of the formula (Ia) derived from the cycloolefin of the formula (I) and a polymoron unit of ethylene and contains, boron on these total polymer units, preferably 1-5-60 molar %, more preferably 25-50 mol%, of the polymer unit of formula (Ia), and preferably 85-40 mol%, more preferably 75-50 mol%, of the polymer unit of ethylene.

The copolymer (a) of a cycloolefin may contain a polymer olefin in addition to the above polymer purity derived from another copolymerizable unsaturated monomer (s). Bovorzugt as such unsaturated monomers are, for. B. a-olefins having 3 to 20 carbon atoms and monomers Kohlonwassoretoffreiho with mindostens two carbon-carbon double bonds in Moldküi. Specific examples of the α-olefins having 3 to 20 carbon atoms are propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentone, 1-hexene, 1-hoptene, 1-octone, 1-nonene, 1-docei, 1-dodecone, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosone. Specific examples of the monomers of the hydrocarbon series having at least two carbon-carbon double bonds in the molecule are linear nonconjugated dienes such as 1,4-hexadione, 1,6-octadiene, 2-methyl-1,5-hexadiene, 4-methyl-1,6 hexadione, 5-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene and 7-methyl-1,6-octadiene; cyclic non-conjugated dienes such as cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornone, 5-methylene-2-norbornene, 6-isopropylidone-norbornene, e-chloromethyl-6-isopropenyl ^ -norbornene and 4,9,5,8-dimethano-3a, 4,4a, 5,8,9,9a-octahydro-1H-benzoindene, 2,3-diisopropylidene-5-norbornene, 2-ethylidone 3-isopropylidene-5-norbornene and 2-proponyl-2,2-norbornadiene. Among these monomers, preference is given to 1,4-hexadiene, 1,6-octadiene and cyclic non-conjugibribronedienes, in particular dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornone, 5-methylene-2-norbornene, 1,4-hexadiene and 1,6-octadiene.

The amount of the polymer moiety derived from these other unsaturated monomers is, in the total of the polymer units derived from the formula (Ia) and ethylene, at most 15 mol%, more preferably at least 1 mol%. The copolymer (a) is essentially a linear random copolymer. That the copolymer (a) has no gel-like structure vornetzte, can be evidenced by the fact that it is completely dissolved in decalin at 135 ⁰ C. The above cycloulefinhaltige random copolymer (a) has an intrinsic viscosity (η) measured in decalin at '35 ⁰ C, of preferably 0.01 to 10DL / g, more preferably from 0.05 to 5 dl / g, a softening temperature (TMA ), measured with a thermomechanischon analyzer of preferably not less than 7O ⁰ C, more preferably 90-250 ° C, more bovorzugt of 100-200 ° C, a glass transition point (Tg) of preferably 5O-230 ° C, more preferably from 70-210 ° C, and a crystallinity, as measured by X-ray diffractometry, of preferably 0 to 10%, more preferably 0 to 7%, especially preferably 0 to 5%.

As the above cycloolefin-containing random copolymer (a), a copolymer having the above-described properties is preferable. The above cycloolefin-containing random copolymer (a), however, may contain another copolymer having properties outside the above-described ranges, for example, a cycloolefin-containing random copolymer having a softening point of less than 70 ⁰ C, especially between -10 and 60 ° C, and a intrinsic viscosity (η), measured in decalin at 135 ⁰ C, from 0.05 to 5dl / g. Of course, as a whole, the physical properties of the resulting copolymer are preferably within the ranges described above.

The above cycloolefin-containing random copolymer (a) can be ζ. Example according to the method proposed by the here occurring Anmolderin in JP-OS'on 60-168708,61-120816,61-115912,61-115916,61-271308,61-272216,62-252406 and 62-252407 ,

Copolymers included in the above cycloolefin-containing copolymer (a) may be used alone or in combination.

The above copolymer (b) and hydrogenation products thereof are explained below.

In the copolymer (b), the cycloolefin of the formula (I) is contained in the form of a polymer unit of the formula (I-b) from the ring-opening polymerization.

Examples of the cycloolefin of the formula (I) for the copolymer (b) are those described with respect to the copolymer (a). The copolymer (b) contains, based on the polymer unit of the ring opening polymerization formol (Ib) and on the ethylene polymer unit, preferably 50 to 100 mol%, more preferably 75 to 100 mol% of the polymer unit of the formula (Ib) and preferably 0 to 50 mol%, more preferably 25 to 50 mol%, particularly preferably 35 to 50 mol%, of the polymer unit of ethylene.

The copolymer (b) may contain a polymer unit derived from other copolymerizable unsaturated monomers as required

 Such unsaturated monomers are cycloolefins of the following formula (III)

Π (R ¹³ -CR ¹⁴ )

wherein R ¹³ and R ^{4 may be the} same or different and each represents a hydrogen atom, a halogen atom or a hydrocarbon group, m is an integer of not less than 2, and a plurality of respective R ' ³ and R ^{14 may be the} same or different ,

Examples of these cycloolefins are cyclomonoolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, cyclonones, cyclodecene, methylcyclopentene, methylcycloheptene, methylcyclooctene, methylcyclonones, methylcyclodecene, ethylcyclopentene, ethylcycloheptene, ethylcyclooctene, ethylcyclonones, ethylcyclodecene, dimethylcyclopentene, dimethylcycloheptene, dimethylcyclooctene, dimethylcyclononone, dimethylcyclodecene and trimethylcyclodecene and Cyclodiolefins such as cyclooctadiene and cyclodecadiene.

The amount of polymer moiety derived from the other cyclooloflonone is at most 60 mol%, preferably

at most 25 mol%, based on the Gosamtmengo dor polymoroinhoit of formol (l-b) and dor of ethylon obgoloitoton

Polymoroinhoit. The obigo by ring-opening polymorization olnos cycloolefins gobildoto copolymor (b) has oino intrinsic viscosity (η),

measured in Dccalin at 13S ⁰ C, of preferably 0.05 to 10dl / o, bovorzugtor of 0.08 to 5dl / g, and eino

Softening temperature (TMA) of preferably not wenlgor than 7O ⁰ C, bovorzugtor of 90 to 300 ⁰ C. Further, the polymer which is formed by ring-opening polymerization of a cycloolefin has the characteristic Ib) olne crystallinity, gomosson

by X-ray diffraction, from 0 to 10%, more preferably from 0 to 7%, preferably from 0 to

The polymer of a ring-opening polymerization containing the cycloolefin component of the formol (I) can be orzougt wordon by subjecting a monomer of the formula (I) to a usual ring-opening polymerization process. Examples of the polymerization catalyst used for this purpose are catalyst systems consisting of an inert halide, nitrate or a

Acotylacetone precursor of Ruthonlum, rhodium, palladium, osmium, iridium, platinum, molybdenum, tungsten or the like and oinom Reducing agents such as an organic tin compound odoi an alcohol, and Katalysatr rsystome, consisting of a Halide or Acetylacotonverblndung of titanium, vanadium, zirconium, tungsten, Molydän o. The like. And one Organoaluminum compound. The molecular weight of the resulting ring opening polymer can be adjusted by adding to a specific tone At the time of ring opening polymerization, an olefin, etc. were incorporated. The ring-opening polymer obtained above can be hydrogenated according to the usual hydrogenating method. For hydrogenation can be used for Hydrogenation of olefin precursor commonly used hydrogenation catalysts. In particular, os

heterogeneous and homogeneous catalysts. Examples of the heterogeneous catalysts are nickel, palladium, platinum and

Solid catalysts in which these metals are deposited on a pad, z. As carbon, silica, Diatomaceous earth, aluminum or titanium oxide, such as nickel / silica, nickel / diatomoenero, palladium / carbon, Palladium / silica, palladium / diatomaceous earth and palladium / alumina. Examples of the homogeneous catalysts are those which are prepared by using a metal as a base,

which belongs to group VIII of the periodic table, e.g. Catalysts that have been formed from a nitride co-clog, such as

Nicholin) htenate / triethylaluminum, cobalt octonate / n-butyllithium, nickel acetylacetonate / triethylaluminum or the like, and a Organometallic precursor of a metal belonging to Group I to III of the Periodic Table, or an Rh compound. The above hydrogenation of the ring-opening polymer is carried out in a homogeneous or heterogeneous system, depending on Catalyst, and under a hydrogen peroxide pressure of preferably 1 to 150 atm at einor temperature preferably between 0

and 18O ⁰ C, more preferably between 20 and 100 ⁰ C performed. The hydrogenation rate may be in accordance with hydrogen pressure,

Reaction temperature, reaction time and catalyst concentration can be adjusted. The copolymer (c) will be explained below. In the copolymer (c), the cycloolefin of the formula (II) in the form of a polymer unit of the formula (II-a) is onthn'ton. Typical examples of the cycloolefin of the formula (II) are 1,4,5,8-dimethano-i, 2,3,4,4a, 5,8,8a, 9a-decahydro (loronono (hereinafter

referred to as DMDF's) of the following formula (H ')

(CH ₃₎ p (CHg) _q (CHg) ₃

wherein p, q and s are as defined above.

Japanese Patent Publication No. 52-62192 discloses such DMDFs as a component of a dihydrotricyclopontadione mixture obtained by hydrogenating two kinds of isomers of tricyclopentadiene. The DMDF's can be by ei. Diels-Alder reaction between 4,7-methano-3a, 5,6,7a-tetrahydro-1H-indenes, which are toilhydriorto products of dicyclopentadienes and cyclopentadienone, or by a Diels-Alder reaction between 4,7- Mothano-3a, 5,6,7-a-tetrahydro-1H-indones and dicyclopentadienes, which can form cyclopentadienes by thermal decomposition under the reaction conditions.

The partially hydrogenated products of dicyclopentadienes can be readily prepared from dicyclopentadienes as starting materials according to a known method according to e.g. DD-PS 0154 293 are produced.

Examples of distinct from the DMDF's polycyclic monomer of the formula (II) are the following: heptacyclo [1 ^3e, 1 ^107, 1 ^1ils, 0.0 ^J7, 0 "," l-EICOS-4-ene

MethylheptacycloH ³ · ,! ¹⁰ ", 1" ^I5 , 0.0 ^{2 7} , 0 ^lus | -oicos-4-en

-10- 297272 nimothvlheptacyclo (1 ^R * .1 .i ^{1017 'II6} .0.0 ⁱ⁷ .0 ^"ie | -oicoe-4-ene

¹¹ · ^ιβ | · β1οοβ · 4 · οη

Nonacyclo | r ⁱ¹ , 1 ⁱ M ^{1) M} , 1 ^l5 ", 0 ^il0 , 0 ⁴ ', 0 ^llll , 0 ^Ul ' | pentacos-6one

These polycyclic monomers may have been produced by a Diels-Alder reaction, etc.

The copolymer (c) contains, based on the total amount of the polymor unit of the formula (II-a) from the cycloolofin of the formula (II) and the polymer unit of ethylene, preferably 10 to 90 mol%, more preferably 20 to 80 mol%, of the polymorolnheit of formula (II-a) and preferably 90 to 10% by mol, more preferably 80 to 20 mol%, of the polymer moiety of ethylene.

The copolymer (c) may, if necessary, contain polymer unit (s) of other copolymorisorbarone unsaturated monomers.

As the aforementioned unsaturated monomers, there are mixtures (hereinafter referred to as "TCPD mixture") of tricyclopentadiene of the following formula (IV)

HgTj (OV J [(CH

wherein j is 0 or 1,

with tricyclopentadione of the following formula (V)

(V) (CH _{3) k} (CH _{3) k} (CH _{3) k}

wherein k is O or 1.

The mixing ratio between the above monomers (polycyclic monomer of formula (IV) / polycyclischos monomer of formula (V)) is preferably V »to ^M / eoMol.

The TCPD mixture can be prepared from a dicyclopentadiene starting material according to a method according to e.g. JP-OS 49 · 49952 can be produced. These tricyclopentadienes are formed as a by-product in the preparation of the DMDF's of the general formula (ΙΓ) and can be used advantageously without separation of the tricyclopentadieno from the DMDFs.

In a copolymer of ethylene, a polycyclic monomer of the general formula (II) (DMDF's of the general formol [II '] in particular) and at least one tricyclopentadiene (hereinafter referred to as "TCPD") selected from TCPD's of the general formulas (IV) and ( V), the molar ratio of ethylene / DMDF's is ¹⁰ Ao to ⁹⁰ Ao, preferably ^M / ao to ⁸⁰ M, and the molar ratio of TCPD's / DMDF's is 4 or less, preferably ¹⁵ M to ⁹⁰ ZiO _{1, more} preferably ² % to ⁶ %. O.

Further examples of the polymerizable unsaturated monomers are linear or branched α-olofino having 3 to 10 carbon atoms and cycloolefins having 5 to 18 carbon atoms.

Specific examples of the α-olefins are propylene, 1-butene, 1-hexene, 3-methyl-butene, 4-methyl-1-pontone, 1-octone and 1-decene.

Among them, preferred are α-olefins having 3 to 6 carbon atoms.

Specific examples of the cycloolefins are cyclopentene and cyclohexene.

In the copolymer of ethylene, or the polycyclischon monomer (especially DMDF's of the general formula | II ')) and the

obigon α-olofine and / or cycloolefin is the molar ratio of ethylene / DMDF's ¹⁰ / w to * ° / o, preferably ²⁰ / w to ¹⁰ Ao, and the molar ratio of (a-olofine and / or cycloolofinl / OMDF's not mohr as 9, preferably ⁹⁰ Ao to ¹ Vm, more preferably e / iobis'Vis.

Other examples of the polymerizable unsaturated monomers are styrenes such as styrene and α-mothylstyrene, norbornono such as Norbornene, mothylnorbornene and ethylnorbornone, norbornene-type compounds such as 4,7-mothano-3,8,5,6,7-a-tetrahydro- IH-lndone and V-methano ^ aa-Sa-a-hydrotro-IH-indene, polyonewio-cyclopontadione, 5-ethyl-lyll-2-norbornene and 1,4- Hoxadienunddgl. It is preferred to use this unsaturated monomoro in oinor amount below 15 mol%, based on the polycyclic Monomer of the formula (II). The copolymer (c ¹ can, for example, according to WO 89/01950 horgestoilt a Vorfahrons according to WO 89/01950 gehdon Copolymerization of ethylene, a polycyclic monomor of the general formula (II) and optionally one or more Monomor (on) in a hydrocarbon solvent in the Gogonwart of a catalyst can be prepared from a

carbonic anhydride soluble vanadium compound and an organoaluminum precursor containing halogen. > it is.

In the copolymer (c), the polycyclic monomer of the formol (II) is mainly in the form of the polymor unit of the above formula

(II-a) included. The copolymer substantially contains polymers of the following formol (VI), dio from

Ring-opening polymerization of the polycyclischon monomer dor formula (II) is derived,

(Vl)

(CH ₃ Jq (CH _3] Tj. (CH _{3) g}

wherein μ, q, r, s and t are as above definiort.

Even if such a polymer unit is contained, its amount is very small. Therefore, the copolymer (c) is chemical

stable.

The transparent resin substrate may be made of the above-described thermoplastic resin according to usual methods such as Injoktionsformgobungsverfahren has been designed. A transparent resin substrate having a desired shape can

easily obtained according to this method.

The recording layer formed on at least one surface of the transparent resin substrate has a per se

known structure. For example, it is composed of an optical memory magnetic layer of a thermal mode recording material, e.g. A low melting point Motall material such as Te and the like, the recording material mainly comprising said low melting point metal material (e.g., Te-C-H recording material, Te-Cr-C-H).

Recording material, etc.) and an organic dye, and a magneto-optical A recording material containing a rare earth element and a 3d transition metal (e.g., TbFeCo or a mixture of TbFeCo with Pt and / or Pd), and if necessary also constructed from a sub-coating layer, dio optionally on

and / or under the optical memory matorial layer such as an antireflection layer

Reflection layer, an optical interference layer, a protective layer and / or an additional layer. The transparent resin substrate having a recording layer on at least one surface may be used as a disk substrate in the

present invention. And two of these disc substrates are adhered to each other directly or through a ring-shaped spacer using an adhesive composition.

As the material for the ring-shaped spacer, it is possible to use the same thermoplastic resins as those for the above

transparent resin substrates used, such as polycarbonate, polymethylmethacrylate and polyolefins. A filler such as TiO ₂ , SiO ₂ or the like may be incorporated in these resins to form the spacer.

The adhesive composition for use in the information recording medium of the present invention contains

as previously described,

(A) a d-olefin polymer,

(B) an ethylene / methyl acrylate copolymer,

(C) a styrene type polymer and

(D) an adhesive,

with the proviso that at least one member of the above components (A) to (D) is modified with an unsaturated carboxylic acid or a derivative thereof.

This composition is a so-called hot melt adhesive, which is melted at elevated temperature and cooled

is hardened. It is therefore used at a high temperature in a molten state.

As the 0, -olefin polymer (A), homodoorer copolymers of α-olefins having 2 to 20 carbon atoms are usable. Preferred examples of the α-olefin polymer are an ethylene / propylene copolymer, a propylene polymer and a Isobutylene. In the present invention, it is preferred to use a mixture of an ethylene / propylene copolymer, propylene polymer and Isobutylonpolymer be used as an α-olefin polymer (A). The ethylene / propylene copolymer, that is not modified with an unsaturated carboxylic acid ods ^r its derivative

(hereinafter referred to as "unmodified") preferably contains, based on the total amount of the polymer units of

Ethylene and propylene, 5 to 80% by weight, preferably 5 to 50% by weight, the polymer content of ethylene and 95 to 20% by weight,

preferably 95 to 50% by weight, of propylene.

The unmodified Ethylon / Propylon copolymer has a preferred melting point (ASTM D-1238) of preferably 0.1

up to 100g / 10mln, more preferably from 0,5 to 50g / 10min.

The unmodified ethylone / propylene Copolymor has ELNO intrlnsischo viscosity (η), gomosson in Docalln at 135 ⁰ C, of

preferably from 0.1 to 6.0 dl / g, preferably from 0.2 to 4.5 dl / g.

Preferred as unmodifiziortes Propylonpolymur are a homopolymer of propylene odor oin Copolymor of propylene with Ethylene or an α-Olefln having 4 to 20 carbon atoms. Examples of α-olefin having 4 to 20 carbon atoms are 1-butene, isobutylene, 4-methylpontone-1,1-Hoxene, 1-Hopton, 1-Octone,

1 -none, 1-decone, 1-dodocone, 1-terracene, 1 -hoxadecene, 1-octadecene and 1-eicosone. In the case of the copolymer, it is preferable that the content of ethylon or α-olofine is 20% by weight or less.

Such a propylene polymer has a melt flow rate (ASTM D-1238) of preferably 1 to 100 g / 10 min,

Preferably, from 1 to 50g / 10min, on.

Preferred as unmodified isobutylon polymor polyisobutyron are a homopolymer of isobutylene or a copolymer

of isobutylene with ethylene. The unmodifizlerto Isobutylonpolymor has an average Molokularzohl of preferentialwoiso500000 or less, more preferably from 2000 to 300000.

The acrylate or methacrylate which is unconjugated for the unmodified ethylonyl / f-methyl acrylate copolymer (B) is an ester of acrylic

or methacrylic acid and represents a hydrocarbon having 1 to 12 carbon atoms.

Specific examples of the Ethylon / Imothlacrylat copolymer include Ethylon / Ethylocrylate Copolymor, Ethylon / Mothylacrylat- Copolymor, ethylene / ethyl methacrylate copolymer and ethylene / methyl methacrylate copolymer. Ethylene / ethyl acrylate copolyinor. or preferably in the present invention. The unmodified ethylene / t-methyl acrylate copolymer (B) contains, by weight, the total amount of polymer uniton of Ethylene and (meth) acrylate, preferably from 99 to 50% by weight, in particular from 95 to 7% by weight, of the polymorphonophenol of ethylene and

1 to 50% by weight, especially 5 to 30% by weight, of the polymoroin unit of (meth) acrylate.

The ethylene / (Moth) acrylate copolymer (B) has a melt flow rate (JIS K 6730) of preferably 0.1 to

300dg / min, more preferably from 1 to 100dg / min.

The styrene-type unmodified polymer (C) is a polymer containing at least one unit selected from dor Styroloinheit and its dorivatoinhoite, as oine unit of the polymer structure in the polymer chain. Examples of this polymer (C)

styrene type are polystyrene, styrene / butadione rubber, styrene / butadiene / styrene block copolymer or styrene / butadiene rubber.

Gum (SBS Blückcopolymer) and a hydrogenation product of a styrene / butadione / styrene block copolymer (SEBS- Block copolymer), a styrene / acrylonitrile copolymer, or a styrene / a-methylstyrene copolymer, a styrene / maleic anhydride Copolymer, a styrene / methyl methacrylate copolymer, a styrene / a-methylstyrene / acrylonitrile copolymer, a styrene / acrylonitrile / Methyl methacrylate copolymer, a styrene / maleic anhydride / acrylonitrile copolymer, a styrene / N-phenylmaleimide Copolymer and mixtures of these polymers with rubber elastomers. Examples of the rubber elastomers are polybutadiene

and acrylic rubber. Examples of mixtures of the above polymers with the rubber elastomers are domestically oin ABS resin,

AES HarzundAAS resin. Such a styrene type polymer (C) has a melt flow rate (ASTM D-1238; 230 ° C χ a load of 2.16 kg)

of preferably 0.05 to 100 g / 10 min, more preferably 0.1 to 50 g / 10 min.

The unmodified styrene-type polymer has a Glasiiborgangspi MKT (Tg) of preferably 50 to 200 ⁰ C, bovorzugter

from 70 to 15O ⁰ C.

Further, as the unmodified adhesive (D), for example, rosin and its derivatives, palm-containing resins, aromatic Petroleum resins, aliphatic cyclic resins (aliphatic resin having a Kohlenstoffrii ι in the polymer structure) such as Cyclopentadione-type polymers, dicyclopentadiene-type polymers, hydrocarbon resins (petroleum resins) having a Carbon ring in the polymer structure is preferred. Preferred examples of rosin derivatives are a hydrogenation product and Esterification product of Rosin. Preferred examples of the cyclopentadiene polymer are a homopolymer of cyclopentadiene

and a copolymer prepared from cyclopentadiene as a main monomer component. Preferred examples of

Dicyclopentadiene polymers are a homopolymer of dicyclopentadiene and oin copolymer made from dicyclopentadiene

as the main monomer component. Preferred examples of the hydrocarbon resins (petroleum resins) having a carbon ring in the polymer structure are resins obtainable by copolymerizing cyclopentadiene and / or dicyclopentadiene with a

Olefin or diolefin having 4 and / or 5 carbon atoms, or aliphatic petroleum resins, obtainable by polymerization of Fraction containing aliphatic Cj-olefins (eg 2-Mothy 1-1-butene and / or 2-Mothyl-U-butone) and / or aliphatic Cj-diolefins (eg, isoprene and / or piperils) in the presence of a cationic catalyst (eg, a Friedel-Craft®). Catalyst), or petroleum resins, obtainable by polymerization of C ₄ - or Cj-Cs fractions in the presence of

cationic catalyst. Among dioson compounds, the aliphatic cyclic resins are most preferred as the adhesive in the present invention. Further, among the aliphatic cyclic resins are petroleum resins having a

Carbon ring in the polymer structure particularly preferred, especially aliphatic petroleum resins. The aliphatic cyclic resin (D) has an average molecular weight of preferably not more than 5,000, more preferably

of 50-3000, in particular 300-3000 and a softening point of preferably (ring or ball method) 30-120 ⁰ C, more preferably from ⁰ 70-12O C.

The aliphatic petroleum resin, which is the most preferred aliphatic cyclic tail, has one Average molecular weight of preferably 300-2000 and a softening point (ring or ball method) of

30-12O ⁰ C, more preferably from 70-120 ⁰ C on.

In the present invention, the component (D) is thus different from the components (A) to (C). In the adhesive composition used in the present invention, at least one of the components (A) to (D) is to have a

be modified unsaturated carboxylic acid or its derivative. The modification with an unsaturated carboxylic acid or its derivative can be carried out by copolymerizing or graft-modifying each polymer of the components (A) to (D).

Graft modification is preferred. Boispiolo dor unsaturated carboxylic acid and its derivative are unsaturated carboxylic acids

such as acrylic, methacrylic, maleic ·, fumaric, Tetrohydrophthel · llncon-, citraconic · · Croton, isocrotonic and Nadin-Säuro ⁿ (ondocis-

Bicyco | 2.2.1.] Hopt-5-ene-1, 3-dicarboxylic acid, acidohalogonido, amides, imides, anhydrides, esters and the like, wio malonyl chloride, Maieimide, Itaconsauroanhydrid, maleic anhydride, Citraconsäureanhydrid, Monomothylmaloat, dimethylmaloate and Glycidylmaloat. Untor this are unsaturated dicarboxylic acids odor doron Anhydrido boborzugt, and Maloinsäuro odor her Anhydrides are particularly preferred. When the unsaturated carboxylic acid or its derivative is grafted to at least one component (A) to (D), may

a variety of bekannton ancestors have been applied, so bois piolo the grafting can be carried out wio follows. The polymorus and the unsaturated carboxylic acid or its derivative are dissolved in oor required amounts for this purpose in oinomium suitable solvents, e.g. Toluene, xylene or the like, and e.g. a radical initiator of oxy-organic peroxide, e.g.

Bonzoyl peroxide, lauryl peroxide or dicumyl peroxide, or a radical initiator such as azobisnitrile dor resulting solution

added. Then, the resulting solution to a temperature not lower than dor Zersotzungstomporatur of the radical initiator is usually 5h heated to a temperature between 50 and 300 ⁰ C, for 1 minute to. The grafting can also be carried out by adding the ungosättigto carboxylic acid or its derivative as a graft monomer and oinon radical initiator dom polymer in a molten state and the entstehondo mixture boi a temperature not below the melting temperature dos

Poly iers usually knots for 1 min to 5h long. The amount of the unsaturated carboxylic acid or its dorivar component in the modified polymer is preferably 0.01

up to 5% by weight. The amount of the unsaturated carboxylic acid or its derivative remaining unreacted in the modified polymer is preferably not more than 50 ppm.

Due to the modification with the unsaturated carboxylic acid or its derivative, the polarity of the Bee composition increased while maintaining its glass transition point, whereby the Adhesive composition is given high adhesion even at high temperature without high To impair adhesion at low temperature. In the present invention, it is desirable that those with the unsaturated carboxylic acid or its derivative to

modifying component is the α-olefin polymer (A).

The above adhesive composition preferably contains 1 to 68% by weight, more preferably 1 to 10% by weight, of α-olefin polymer (A), Ibis 30% by weight of ethylene / (meth) acrylic copolymer (B), 1 to 30% by weight of styrene-type polymer (C) and 30 to 95% by weight Adhesive (D). It more preferably contains from 5 to 50% by weight of α-olefin polymer (A), from 5 to 20% by weight of ethylene / (meth) acrylate. Copolymer (B), 5 to 20% by weight of styrene type polymer (C) and 35 to 70% by weight of adhesive (D). In the above tanning composition of the present invention, the α-olefin polymer (A) is preferably a mixture

an ethylene / propylene copolymer, a propylene copolymer, and an isobutylon polymer, as described above. In this case, the α-olefin polymer component (A) preferably contains 1 to 60% by weight, more preferably 5 to <10% by weight, of one

Ethylene / propylon copolymer, 1 to 60% by weight, more preferably 5 to 40% by weight, of a propylene copolymer and 1 to 30% by weight,

more preferably 5 to 20% by weight of an isobutylene polymer, provided that the total amount of these three subcomponents does not exceed 68% by weight.

The adhesive composition of the present invention is a hot melt adhesive composition and has

preferably, a melt viscosity boi 17O ⁰ C of 20,000 to 200,000 cps, preferably 2,000 to 1,500,000 cps (measured at a shear rate of 17.6 s ^-1 using an Emila rotary viscometer)

Melt viscosity dio exceeds the aforementioned upper limit of 200,000, the handling of the adhesive composition

At the nozzle outlet or in the roll coating undesirably reduced. The softening point of

The adhesive composition of the invention is preferably not less than 120 ° C, more preferably 140 to 200 ° C. The above adhesive composition of the present invention may contain additives such as a filler in addition to the above Components (A) to (D) included. Inorganic and organic fillers can be used. Preference is given to fillers for conventional plastics such as clay, silica, mica, talc, calcium carbonate, Alumina, titanium oxide, carbon black, graphite, and the like. The particle diameter of the filler is preferably not more than

100pm, more preferably not more than 10pm, though or not particularly limited. The amount of filler is usually 1 to 100 parts by weight based on 100 parts by weight of the adhesive composition. The filler is in the

Adhesive composition distributed homogeneously. Since the adhesive matrix of the invention contains components (A), (B), (C) and (D) and at least one of Components (A) to (D) is modified with an unsaturated carboxylic acid or its derivative, it is characterized with respect to

thermal resistance and adhesion under high and low temperatures.

According to the investigations of the present inventors, the following has been clearly found. A Adhesive composition containing the above fine particles of the filler has a performance similar to that

is equivalent to the above-specified adhesive composition even if the above component (B), i. H. an ethylene / (methacrylate copolymer, not containing and not modified with an unsaturated carboxylic acid or its derivative.

Therefore, according to the present invention, there is provided secondly an information recording medium that is formed

is glued by two disc substrates together, of which at least one of the two disc substrates one

Recording layer on at least one surface of a transparent resin substrate, wherein one Adhesive composition used and the adhesive composition

(A) an α-olefin polymer,

(C) a styrene type polymer,

(D) an adhesive and

(E) contains fine filler particles.

It should be clear that the above explanations regarding the components (A), (C), (O) and (E) as well as the Information recording medium also applicable to the above recording medium of the second invention, it

Unless something else is highlighted below.

The above tanning composition preferably contains 1 to 68% by weight, more preferably 1 to 60% by weight, of α-olefin polymer (A),

1 to 30% by weight of styrene type polymer (C), 30 to 95% by weight of adhesive (D) and 1 to 50% by weight of filler particles (E).

More preferably, it contains 1 to 60% by weight, more preferably 5 to 60% by weight, of α-olefin polymer (A), δ to 20% by weight of polymer of Styrene type (C), 45 to 90% by weight of adhesive (D) and 5 to 35% by weight of fine filler particles (E). In the aforementioned adhesive composition of the present invention, the α-olefin polymer (A) is similar

preferably a blend of an ethylene / propylene copolymer, a propylene copolymer and an isobutylene polymer as previously described. In this case, the α-olefin polymer component (A) preferably contains 1 to 60% by weight, more preferably 5 to 40% by weight, of an ethylene / propylene copolymer, 1 to 6% by weight, more preferably 5 to 40% by weight, of a propylene copolymer and 1 to 30wt .-%, more preferably 5 to 20Gow .-%, olnos isobutylene;. nit provided DAU, β total amount of these three subcomponents 60 wt .-% non upper rises.

The above-mentioned a-Olefinpolymor (A), styrene-type polymer (C) or adhesive (D) may optionally with a

be modified unsaturated carboxylic acid or its derivative.

The above filler-containing adhesive composition preferably has a melt viscosity of 17O ⁰ C of

30000 to 10000Ocps (measured at a shear rate of 17.6 s ^-1 using an

Rotationsviskometors). The melt viscosity of the adhesive composition containing the components (A), (C) and (D),

Preferably, before incorporation of the fine filler particle (E), it is at least 200 μ ocps.

Each of the information recording media of the present invention is prepared by using any of the above Adhesive compositions applied to the (one of) the above disk substrates by means of a roller or nozzle and they

glued together. An information recording medium having a spacer between the disc substrates is prepared by placing an annular spacer on a disc substrate prior to curing

Adhesive coating composition, then the coating composition hardens, the above adhesive composition on the

annular spacer in the same manner and adheres another disc substrate. In general, that will

Information recording medium produced by further introduction and attachment of a hub. In the present invention, the frame of the information recording medium includes all the recording media

an information recording layer such as optical disks or flexible optical disks.

The information recording medium of the present invention is prepared by forming a disk substrate having a Recording layer, to another disc substrate having a recording layer, with the Stick recording layers inside or directly via an annular spacer, wherein the Adhesive composition is applied thereto. Information recording media prepared as above not only have excellent heat resistance,

but also adhesive strength at a temperature lower than ordinary temperature, and that because the above

Adhesive compositions of the first and second inventions can be used to form the disc substrates or the To glue disc substrate and the annular spacer. Therefore, even if the Information recording media under high temperature, high humidity conditions and environmental conditions

be used under low temperature over a long period of time, neither deviation nor elimination between the

Disc substrates, and deformation as by advancing is minimized. The present invention will now be explained with reference to examples and drawings. Fig. 1 is a cross-sectional view of a configuration of the information recording medium of the present invention, in which

the numeral 1 indicates an information recording medium. The disk substrates 2 a and 2 b are connected to each other with the

Recording layers 3 a and 3 b inwardly by annular spacers 4 a and 4 b by means of a adhesive layer 5

bonded. In the middle of a central hole 6 is provided.

Figures 2 (a) and 2 (b) show schematically a process step of applying a hot melt adhesive composition

the surface of a disk substrate on the side of the recording layer by means of a nozzle of a dispenser.

FIGS. 3 (a) and 3 (b) schematically show a process step of bonding disc substrates to which a Hot melt adhesive composition is applied, by means of pressure exerted by an ordinary Temperature operating pressing device. In Fig. 2 (a), numeral 11 indicates a hot melt adhesive composition, and the dispenser is a container in which the Hot melt adhesive composition 11 is stored. A needle nozzle 13 is attached to the outlet part of the container ^

and below that is a revolving stage 14. The revolving stage 14 absorbs the disc substrates 2a, 2b by vacuum and rotates them in the Α direction. At this time, the adhesive composition 11 stored in the container 12 is replaced by the

Needle nozzle 13 is discharged to form the adhesive layer 5. The turntable 14 is constructed so that by rotation

caused deviations are prevented. In the present invention, the preferred thickness is

Adhesive layer 10 to 300 pm. The thickness of the adhesive layer 5 can be determined by means of a distance h between the needle nozzle 13 of the Container 12 which is movable up and down, and the disc substrate 2 a, 2 b and the rotational speed of the rotary stage 14th

be set. The ejection of the adhesive composition 11 may be carried out by supplying it under gas pressure or mechanically with a pump. This embodiment shows a case of feeding using nitrogen as a gas. Fig. 2 (b) shows independent application of the adhesive composition 11 wherein the adhesive composition is applied independently to a portion to which the outer annular spacer 4a is adhered and to a portion to which the inner annular spacer 4b is adhered. In this case, the container 12 is also designed so that it can move in the radial direction of the disc. Fig. 2 (b) shows an improved construction of the

Container 12, with which one applies the adhesive composition 11 on the two of these two sections at the same time

can, so that the inner and outer annular spacers 4 a and 4 b are fastened simultaneously.

The disk substrate 2a having the adhesive layer δ formed as above is applied to a positioning pin 23 of the fixed lower die 21 of an ordinary temperature press apparatus shown in Fig. 3 (a) on which the annular spacers 4a and 4b are mounted Molded part 21 is arranged. Then, the disk substrate 2a is adhered to the annular spacers 4 a and 4 b under pressure by moving a bewngtwen upper mold part 22 in the B direction. The adhesive layer 5 is cured by being cooled to a temperature below the melting temperature of the adhesive composition 11, whereby the disc substrate 2 a and the annular spacers 4 a and 4 b are glued together. Further, the adhesive composition 11 is similarly applied to the annular spacers 4a and 4b of the disk substrate 2a according to a method shown in FIG. Thereafter, the disk substrate 2a is placed on the fixed lower mold 21 as shown in Fig. 3 (b), and the substrate 2b is placed co with the recording film Ob opposite to the disk substrate 2a, and it is adhered thereto under pressure. by moving the movable upper mold 22 in the B direction, thereby producing the information recording medium 1.

In addition, the information recording medium 1 can be prepared by directly adhering the Scheibonsubstrate 2 a and 2 b with the hot melt adhesive composition 11, without using the annular spacers 4 a and 4 b between them,

Examples There have been a variety of adhesive compositions according to the invention and of

Vorgleichsklebstoffzusammensetzungon subjected to tests under environmental conditions, under conditions of a temperature of 8O ⁰ C and a humidity of 85%, and appearance and deformation ratio (mrad) (before and after the test) after 500h evaluated.

Deformation ratio (mrad) = Deformation before test (initial stage)

Further, the cold-temperature adhesiveness was evaluated by performing a drop test with the information recording media dropped from a height of 76 cm 30 times each at 0 ° C., and the degree of cleavage at the bonded spots was observed Emila · rotational viscometer at 17O ⁰ C at a shear rate of 1.76s " ¹ measured.

example 1 A hot melt adhesive composition comprising 24.4% by weight of a maleic anhydride graft product was used

(Maleic anhydride content: 1.5 wt%) of an ethylene-propylene copolymer having an ethylene content of 35 wt% and a propylene content of 65 wt%, 8 wt% of a random polypropylene resin having an ethylene unit content of 5 wt%, and one Content of the propylene unit of 95% by weight, 10% by weight of an ethylene / ethyl acrylate resin having a

Ethyl acrylate content of 25% by weight, 9.6% by weight of a hydrogenation product of a styrene / butadiene / styrene copolymer (SEBS) Copolymer) having a styrene content of 38% by weight, 9.6% by weight of a polyisobitylene having an average molecular weight

of about 80,000 and 38.4Gew .-% of an aliphatic cyclic resin (aliphatic petroleum resin) with a

Average molecular weight of about 500 contained. As a transparent resin substrate, a resin prepared by copolymerizing ethylene with 1,4,5,8-dimethano-ethylene was used.

1,2,3,4,4 a, 5,8,8 a-octahydronaphthalene

and an ethylene content, measured by ³ C-NMR, of 62 mol%, an MFR (260 ⁰ C) of 35g / 1min, an intrinsic viscosity (η), measured in decalin at 135 ⁰ C, of 0.47 dl / g, and had a TMA of 148 ° C. As the annular spacer, polycarbonate resin spacers having a thickness of 0.5 mm were used. A Te-FiIm was used as an optical memory layer.

An information recording medium 1 as described above was prepared from the above adhesive composition and the components according to the above-described production method, and subjected to the above environmental test. The thickness of the adhesive layer was about 120μηι. Table 1 shows the results.

Example 2

Example 1 was repeated except that the hot melt adhesive composition was replaced with a hot melt adhesive composition containing 14.4% by weight of a maleic anhydride graft product (maleic anhydride content: 1.5% by weight) of an ethylene / propylene copolymer having an ethylene content of 35% by weight % and a propylene content of 65% by weight, 8% by weight of a propylene random resin having an ethylene unit content of 5% by weight and a propylene unit content of 95% by weight, 10% by weight of an ethylene / ethyl acrylate resin having an ethyl acrylate content of 25% by weight, 19.6% by weight of a maleic anhydride graft product (maleic anhydride content: 1.0% by weight) of a SEBS copolymer (a hydrogenation product of a styrene / butadiene-styrene copolymer) having a styrene content of 38% by weight. %, 9,6Gew .-% c 'nes Polyisobutylenes having a mean molecular number of about 80000 suwie 38,4Gew .-% of an aliphatic cyclic resin (aliphatic petroleum resin) having an average molecular weight of about 4,500. Table 1 shows the results.

Table 1

Example 1 Example 2

120000 100000 1.0 0.98 no change no change

Melt viscosity (cPs) Deformation ratio (mrad) Tioftemperature drop test

The information-providing mediator in Test Examples 1 and 2 according to the present invention contained, as an adhesive aggregate to which disc substrates were adhered, a hot-melt adhesive comprising the ethylene-propylene copolymer (A), the polypropylene resin (B), the ethylene-acrylate resin ( C), the styrene-type resin (D), the polyisobutylene resin (E) and the aliphatic-cyclic resin (aliphatic petroleum resin) (F), provided that at least one of the components (A) to (F) is substituted with a unsaturated carboxylic acid or its derivative was modified. For this reason, as shown in Table 1, the application of the adhesive composition was easily carried out, and even when the information recording media were allowed to stand under high temperature, high humidity or low temperature conditions for a long period of time, deviation and splitting occurred between the bonded-together disks Substrate did not open, and the deformation of the media remained small.

Example 3

An adhesive composition containing 100 parts by weight of a hot melt adhesive and 10 parts by weight of a hydrophobic silica (trade name R-972, supplied by Nippon Aerosil K.K., average particle diameter 0.017 μm) was used. The aforementioned hot-melt adhesive contained 18% by weight of a mi.

Maleic anhydride modified product (maleic anhydride content: 1 wt%) of an ethylene / propylene copolymer having an ethylene content of 35 wt% and a propylene content of 65 wt%, 10 wt% of a random copolymer of ethylene / propylene containing the ethylene unit of 5% by weight and a content of the propylene content of 95% by weight, 12% by weight of a SEBS resin copolymer having a styrene content of 38% by weight, 12% by weight of a polyisobutylene having an average number of about 80,000 and 48% by weight. % of an aliphatic cyclic resin (aliphatic petroleum resin) having an average number of about 500.

As the transparent resin substrate, a resin prepared by copolymerizing ethylene with 1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthaiine and having an ethylene content as measured by ' ³ C-NMR, of 62 mol%, an MFR (260 ⁰ C) of 35g / 10min, an intrinsic viscosity (η), measured in decalin at 135 ⁰ C, of 0.47 dl / g and a TMA of 148 ⁰ C showed. As the annular spacers, spacers made of a polycarbonate resin having a thickness of 0.5 mm were used. A Te-FiIm was used as an optical memory layer.

The adhesive layer had a thickness of 120μ.

An information recording medium 1 made of the above adhesive composition and the components according to the above-described production method was prepared and subjected to the above environmental test. Table 2 shows the results.

Example 4

Example 3 was repeated except that an adhesive composition containing 100 parts by weight of the same hot melt adhesive as in Test Example 3 and 30 parts by weight of a mica (100M, trade name, supplied by Yamada Mica Kogyosho, average particle diameter 100 to 200 μm) was used. Table 2 shows the results.

Belsplel5

Example 3 was repeated except that an adhesive composition containing 100 parts by weight of the same hot melt adhesive as in the Test Example was added 3.50 parts by weight of calcium carbonate (Escalon # 200, trade name, supplied by Sankyo Seifun KK, through particle diameter 2.0 μm) and 0 , 1 part by weight talc (JA 13 R, trade name, supplied by Asada Seifun KK). Table 2 shows the results.

Table 2

Example 3 Example 4 Examples

Melt viscosity (cps) 50000 57000 53000

Deformation ratio (mrad) 1.00 0.98 1.10

The information recording media in Test Examples 3 to 5 according to the present invention contained an adhesive composition containing a hot melt manger (filler) (e) with which the disk substrates were adhered to each other. Therefore, the adhesive composition had high thixotropic properties and its application was easy to perform. Even when the information recording media was allowed to stand under high temperature and high humidity conditions for a long time, deviations between the two substrates did not occur, and deformations such as warpage remained small.

Claims (29)

An information recording medium formed by adhering two disc substrates with an adhesive composition, wherein at least one of the two disc substrates has a recording layer on at least one surface of a transparent resin substrate thereof, and the adhesive composition has the following components (A) to (D): (A) an α-olefin polymer, (B) an ethylene / vinyl-acrylate copolymer, (C) a styrene type polymer and (D) an adhesive with the proviso that at least one of the components (A) to (D) is modified with an unsaturated carboxylic acid or a derivative thereof. An information recording medium according to claim 1, characterized in that the adhesive is an aliphatic cyclic Haiy. An information recording medium according to claim 1, characterized in that the α-olefin polymer (A) is a homo- or copolymer of an α-olefin having 2 to 20 carbon atoms. The information recording medium according to claim 1, characterized in that the α-olefin polymer (A) represents at least one member selected from the group consisting of an ethylene / propylene copolymer, a propylene polymer and an isobutylene polymer. The information recording medium according to claim 1, characterized in that the α-olefin polymer (A) is a mixture of an ethylene / propylene copolymer, a propylene polymer and an isobutylene polymer. An information recording medium according to claim 1, characterized in that the ethylene / (meth) acrylate copolymer is an ethylene / ethyl acrylate copolymer. An information recording medium according to claim 4, characterized in that the ethylene / propylene copolymer contains 5 to 80% by weight of polymer ionene ethylene. An information recording medium according to claim 4, characterized in that the propylene polymer is a homopolymer of propylene or a copolymer of propylene with an α-olefin having 4 to 20 carbon atoms. The information recording medium according to claim 4, characterized in that the isobutylene polymer is a homopolymer of isobutylene or a copolymer of isobutylene with ethylene. The information recording medium according to claim 1, characterized in that the ethylene / ethyl acrylate copolymer (B) contains 1 to 50% by weight of polymer units of ethyl acrylate. The information recording medium according to claim 1, characterized in that the styrene type polymer (C) is at least one member selected from the group consisting of polystyrene, styrene / butadiene / styrene copolymer and a hydrogenation product thereof, styrene / acrylonitrile Copolymer, styrene / a-methylstyrene copolymer, styrene / maleic anhydride copolymer, styrene / methyl methacrylate copolymer, styrene / N-phenylmaleimide copolymer, styrene / a-methylstyrene / aoronitrile copolymer, styrene / acrylonitrile / methyl methacrylate copolymer, styrene / Maleic anhydride / acrylonitrile copolymer, as well as mixtures thereof with rubbery elastomers. The information recording medium according to claim 1, characterized in that the adhesive (D) is at least one member selected from the group consisting of rosin and the derivatives thereof, terpene-containing resins, a cyclopentadiene polymer and a petroleum resin. An information recording medium according to claim 1, characterized in that the α-olefin polymer (A) is a copolymer modified with an unsaturated carboxylic acid or its derivative. The information recording medium according to claim 1, characterized in that the transparent resin substrate is composed of a copolymer of ethylene with a cycloolefin represented by the following formula (I) (I) wherein R ¹ to R ^{8 may be the} same or different and each is a hydrogen atom, halogen atom or a hydrocarbon group, R ⁹ to R ^{12 may be the} same or different and each is a hydrogen atom, halogen atom or a hydrocarbon group, or a combination of R ⁹ and R ¹⁰ or R ¹¹ and R ^{12 may be} a divalent hydrocarbon group and a combination of R ⁹ or R ¹⁰ and R ¹¹ or R ¹² may form a ring and η is 0 or a positive integer, with the proviso that when η is 2 or more, a plurality of R ⁵ , a plurality of R ⁸ , a plurality of R ^7, or a plurality of R ^{8 may be the} same or different. 15. An information recording medium according to claim 14, characterized in that the copolymer has an intrinsic viscosity (η), measured in decalin at 135 ⁰ C, from 0.01 to 10dl / g. 16. An information recording medium according to claim 14, characterized in that the copolymer has a softening temperature of not less than 7O ⁰ C. The information recording medium according to claim 1, characterized in that the adhesive composition comprises 1 to 80% by weight of α-olefin polymer (A), 1 to 30% by weight of ethylene / (meth) acrylate polymer (B), 1 to 30% by weight of polymer styrene type (C) and 30 to 95 wt.% of adhesive (D). The information recording medium according to claim 1, which is an optical recording medium. 19. Adhesive composition which contains: (A) an α-olefin polymer, (B) an ethylene / d-vinyl methacrylate copolymer, (C) a styrene type polymer and (D) an adhesive, with the proviso that at least one of the components (A) to (D) is modified with an unsaturated carboxylic acid or a derivative thereof. 20. Use of an adhesive composition for producing an information recording medium, which comprises: (A) an α-olefin polymer, (B) an ethylene / (meth) acrylate copolymer, (C) a styrene type polymer and (D) an adhesive, with the proviso that at least one of the components (A) to (D) is modified with an unsaturated carboxylic acid or a derivative thereof. Use according to claim 20 of an adhesive composition for the preparation of an information recording medium, characterized in that the adhesive is an aliphatic cyclic resin. Use according to claim 20 of an adhesive composition for the preparation of an information recording medium, characterized in that the ethylene / (meth) acrylate copolymer is an ethylene / ethyl acrylate copolymer. 23. An information recording medium formed by individually bonding together two disk substrates having an adhesive composition having a recording layer on at least one surface of a transparent resin substrate thereof, said adhesive composition containing the following components: (A) an α-olefin polymer, (C) a styrene type polymer, (D) an adhesive and (E) fine filler particles. An information recording medium according to claim 23, characterized in that the α-olefin polymer is an α-olefin homo- or copolymer modified with an unsaturated carboxylic acid or a derivative thereof. An information recording medium according to claim 23, characterized in that the α-olefin polymer (A) is a mixture of an ethylene-propylene copolymer, a propylene polymer and an isobutylene polymer. 26. An information recording medium according to claim 23, characterized in that the fine filler particles are organic or inorganic fillers having a particle diameter of not more than ΙΟΟμιη. The information recording medium according to claim 23, characterized in that the adhesive composition comprises from 1 to 80% by weight of α-olefin polymer (A), 1 to 30% by weight of styrene type polymer (C), 30 to 95% by weight of adhesive ( D) and 1 to 50 wt .-% of fine filler particles (E). 28. An adhesive composition for use in an information recording medium, comprising: (A) a-olefin polymer, (C) a styrene type polymer, (D) an adhesive and (E) fine filler particles. 29. Use of an adhesive composition for producing an information recording medium containing: (A) a-olefin polymer, (C) a styrene type polymer, (D) an adhesive and (E) fine filler particles.