JPS61138648A - Optical disk - Google Patents

Abstract

PURPOSE:An optical disk that is a composition of a resin optical disks combined with a specific organic compound with 2-benzofuran skeleton, thus causing no deterioration in mechanical properties, even when it is molded at elevated temperature without formation of voids and silver streaks. CONSTITUTION:To 100pts.wt. of a resin for optical disks such as polymethyl methacrylate, are added 0.01-5pts.wt. of an organic compound having 2- benzofuranone skeleton which may be substituted and is represented by the formula (R<1>, R<2> may be identical or different and represent H, alkyl which may be substituted or may bond to alkylidene group which may be substituted through a double bond or in case that it is not bonded through a bouble bond, one of then is H; R<3>-R<6> are H, alkyl which may be substituted) and has an organic group bonding to at least one of H or double bond in the 3-position, preferably in addition, a primary antioxidant such as a phenolic antioxidant and/or a secondary antioxidant such as a phosphoric antioxidant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc with improved productivity and quality stability.

[Prior art]

Optical memory technology, which uses laser light to record and reproduce information, can store a much larger amount of information than magnetic memory technology, which is the most common memory technology, and has the ability to use random access to retrieve necessary information at will. Due to its excellent functionality and the fact that there is no risk of the head coming into contact with the recording medium during playback and shortening the life of the recording medium or the head, it has recently attracted attention and various proposals for practical use have been made.

By the way, substrates for optical memory recording media (so-called optical disks) that have been proposed or actually commercialized include polymethyl methacrylate (PMMAJ) and polycarbonate 1' (PC). -Pentene (PMP), etc.

All of these resins are transparent resins, and while ordinary resin molding methods are used to mold the disk substrate, injection molding is most preferably used from the viewpoint of productivity. In molding disk substrates using this injection molding method, highly fluid resin is molded at a temperature as high as possible in order to reduce birefringence and to allow the molten resin to flow into every corner of the mold. There are many cases. However, exposing the resin to such a high-temperature atmosphere causes deterioration of the resin, which naturally weakens the mechanical strength of the resulting product and causes scorch inclusions, making it unusable as an optical disc. There is a problem with this. This problem can be solved to some extent by adding an antioxidant to the resin. Another problem is the fact that manufactured disk substrates often have small voids. Although it can be accepted that this phenomenon applies to injection molding in general, methods such as pre-drying the material resin or adding air vents to the mold, which have been considered effective in solving this type of problem, cannot be used to The production of disk substrates by high-temperature injection molding using plastic resins is insufficient.

Another problem is that the bit portions and guide grooves of the disk are not accurately transferred to the disk substrate.

Yet another problem is that silver streaks may appear on or inside the disk substrate, which often occurs even if the material resin is pre-dried for a sufficient amount of time, and is a source of headache for those skilled in the art. It has become.

[Problem that the invention seeks to solve]

In view of the current situation, the present inventors have determined that, in order to improve productivity, there is no deterioration in mechanical properties, no generation of voids, good transferability of pits or guide grooves, and no silver streaks even when high-temperature injection molding is performed. As a result of repeated studies to see if it was possible to obtain an optical disk free of this problem, it was discovered that the objective could be achieved by adding a specific compound, detailed below, to the resin.

[Means for solving problems]

That is, the present invention uses an organic compound having an optionally substituted 2-benzofuranone skeleton having either at least one hydrogen atom or an organic group bonded by a double bond at the 5th position to a resin for optical discs. This invention relates to an optical disc containing the following.

[For production]

As the optical disc resin constituting the optical disc of the present invention, any resin may be used as long as it has excellent transparency, good non-birefringence, and well-balanced mechanical strength.
Specifically, in addition to the above-mentioned PMMA, PC, and PMP, there are polystyrene (PG) and the like.

It goes without saying that these PMMA, PS%PC, and PMP may be copolymers containing a small amount of copolymerizable comonomer components in addition to homopolymers. For example, P
As MP, not only a homopolymer of 4-methyl-1-pentene but also 4-methyl-1-pentene and ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-
α of decene, 1-tetradecene, 1-octadecene, etc.
- Copolymers with olefins can be used.

What organic compounds are added to the resin for optical discs?

It is an organic compound having an optionally substituted 2-benzofuranone skeleton having either at least one hydrogen atom or an organic group bonded by a double bond at the 5th position.

More specifically, it is an organic compound having a 2-benzofuranone skeleton represented by the following formula (R), where R and R2 are hydrogen, optionally substituted alkyl, cycloalkyl, aryl, aralkyl. , hydroxyl, halogen, carboxyl, 2-benzofuranone radical, each fiM - or an alkylidene, cycloalkylidene, arylalkylidene which may be different or alternatively substituted together and bonded by a double bond. R3-R6 are hydrogen, optionally substituted alkyl, cycloalkyl, aryl, aralkyl, alkoxy, alkyl or hacycloalkyl, or aryl or aralkyl. or heterocyclocarbonyloxy, alkyl or hacycloalkyl or aryl or aralkyl or alkoxy or ami7carboel, arylmercapto, carboxyl, hydroxy, halogen, nitro, -CH=O or piperidine nucleus, piperazine nucleus or piperazinone nucleus-containing group, Furthermore, 2-
The benzofuranone radicals may be different or different each time, or two adjacent ones may mutually form a ring.

The compound of general formula (1) basically consists of (4) a single 2
- an organic compound having a benzofuranone nucleus, (B) one 2-benzofuranone nucleus directly or indirectly containing 2
- Organic compounds having two or more 2-benzofuranone nuclei to which one or more benzofuranone is bonded.

Specific examples of such compounds include those shown in the following table.

Table 1 Table 2 Table 2 (continued) Table 2 (continued) Table 2 (continued) The optical disc of the present invention contains an organic compound having a 2-benzofuranone skeleton in an amount of 0.01 to 100 parts by weight of the optical disc resin. 5 parts by weight, preferably 0.05 to 1 part by weight, more preferably 0.05 to 1 part by weight. j~0.5 part by weight is blended. By incorporating this organic compound, there is almost no decrease in mechanical strength even when manufactured by injection molding at high temperatures, that is, around 300°C, and the generation of voids and silver streaks can be almost completely prevented. is a completely unexpected effect. Furthermore, high-temperature injection molding has become possible, which improves the fluidity of the resin during molding, making it possible to mass-produce optical discs with extremely stable quality.

It should be noted that the range of the amount of the organic compound blended is such that if too much is blended, the initial physical properties of the optical disc may not be maintained stably over a long period of time, and if it is too small, the desired effects of the present invention may not be achieved. Or, even if it were to occur, it was set because it would not be effective enough to endure in practical terms.

Moreover, as a preferred embodiment of the present invention, a primary antioxidant and/or a secondary antioxidant may be used in combination.

The blending amount of these materials is 0.005 to 5 parts by weight, preferably 0.01 to 1 part by weight, and more preferably 0.03 to 0.5 parts by weight based on 100 parts by weight of the resin for optical discs. Although there are phenolic and amine antioxidants, most of the amine antioxidants exhibit coloring properties, so it is preferable to use phenolic antioxidants.

Examples of phenolic antioxidants include 2゜6-tert-butyl-p-cresol, stearyl (3
, 3-dimethyl-4-hydroxybenzyrunthioglycolate, stearyl-β-(4-hydroxy-3,5-
di-tert-butylphenol) propionate, distearyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate), 2.4.6-trisC3
, 5'-tert-butyl-4'-hydroxybenzylthio)-1,3,5-) riazine, 2,2'-ethylidenebis(4,6-tert-butylphenol).

2.2'-Oxamidobis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl]propionate], distearyl (4-hydroxy-5-methyl-5-tart-butylbenzylcomalonate), 2.
2-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di'tert-butylphenol), 2,2'-methylenebis(6-(1-methylcyclohexyl) p- cresol], bis[3,5-bis(4-hydroxy-3-te
rt-butylphenyl]butyric acid]glycol ester, 4,4'-butylidene bis(6-tert
-butyl-m-cresol), 1,1.3-)lis(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, bis(2-tert-butyl-4-
Methyl-6-(2-hydroxy-5-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 1
．． 3.5-tris(2,6-dimethyl-3-hydroxy-4-tart-butyl)benzyl isocyanurate,
1.3.5-)lis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-drimethylbenzene, tetrakis[methylene-3-<3.5-di-tert
ert-7'thyl-4-hydroxyphenylpionate comethane, 1,3.5-)lis(3,5-dit
ert-butyl-4-hydroxybenzyl)isocyanurate, 1,3.5-)lis(+3.5-di-tert
-butyl-4-hydroxyphenyl]propionyloxyethyl]isocyanurate, 2-octylthio-4,
6-di(4-hydroxy-3,5-di-tert-butyl)phenoxy-1,3,5-)riazine, 4,4'-
Phenols such as thiobis(6-tert-butyl-m-cresol) and 4,4'-butylidenebis(2-
tert-butyl-5-methylphenol) carbonic acid oligoester (for example, degree of polymerization 2, 3, 4, 5, 6, 7, 8)
．． Examples include polyhydric phenol carbonate oligoesters such as 9.10).

There are phosphorus-based and sulfur-based secondary antioxidants,
Phosphorus-based antioxidants are preferred, and examples of such phosphorus-based antioxidants include trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, and octyl-phosphite.
diphenylphosphite, tris(2,4-diter)
t-Butylphenyl) phosphite, triphenyl phosphite, tris(butoxyethyl) phosphite, tris(nonylphenyl) phosphite, distearylpentaerythritol diphosphite, tetra(tridecyl)-1,1,3-) phosphite (2-methyl-5-ter
t-butyl-4-hydroxyphenyl)/butane diphosphite, tetra(C1° to C15 mixed alkyl)-4
゜4'-Isopropylidene diphenyl diphosphite.

Tetra(tridecyl)-4,4-butylidenebis(5-
Methyl-6-tart-butylphenol]duphos 7
aito, tris(3,5-tert-butyl-4-
hydroxyphenyl) phosphite, tris(mono-dimixed nonylphenyl) phosphite, hydrogenated-4,4-
Impropylidene diphenol polyphosphite, bis(octylphenyl) bis(4,4'-butylidene bis(3-methyl-6-tert-butylphenol))
@1,6-hexanediol diphosphite, phenyl 4,4-impropylidene diphenol pentaerythritol diphosphite, bis(2,4-diter
t-butylphenyl) pentaerythritol diphosphite, bis(2,b-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, tris(4,4'-isopropylidene bis(2-tert
-butylphenol)] phosphite, phenyl diisodecyl phosphite, diC nonylphenyl) pentaerythritol diphosphite, tris(1,3-distearoyloxyisopropyl) phosphite, 4.
4'-Isopropylidene bis(2-tert-butyl enol) diC nonylphenyl] phosphite, 9#
Examples include 10-di-human o-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis[2,4-di-tert-butylphenylon-4,4'-biphenylene diphosphonite, and the like.

Furthermore, a light stabilizer may be added, for example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4
-n-octoxybenzo7e/n-? .

2'-di-hydroxy-4-methoxybenzophenone,
2.4-'; Hydroxybenzophenones of hydroxybenzophenonato, 2-(2'-hydroxy-3'
-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3゜5-t6z-t-phthylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy -5'
-methylphenyl)benzotriazole, 2-(2'-
Benzotriazoles such as hydroxy-5,5'-di-tert-amylphenylbenzotriazole, phenylsalicylate), p-tert-butylphenyl salicylate, p-tert-butylphenyl salicylate, 2,4-di-tert-butyl Phenyl-3,5-
di-tert-butyl-4-hydroxybenzoate,
benzony) such as hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2.2
'-thiobis(4-tert-octylphenol)N
i salt.

(2,2'-thiobis(4-tert-octylphenyl))-n-butylamine N1, (5,5-di-t
Nickel compounds such as ert-butyl-4-hydroxybenzyl)phosphonic acid monoethyl ester N1 salt, α
-cyano-β-methyl-β-(p-methoxyphenyl)
Substituted acrylonitriles such as methyl acrylate and HN
'-2-ethylphenyl-N-2-ethoxy-5-te
Oxalic acid dianilides such as rt-butylphenyl oxalic acid diamide, N--2-ethylphenyl-N-2-ethoxyphenyl oxalic acid diamide, bis(2,2,6,
6-tetramethyl-4-piperidine) Sepashade, poly(((6-(1,1,3,3-tetramethylbutyl)
imino l-1,3,5-toIIazine-2,4-diyl[4-(2,2,6,6-titramethylbiperazyl)
imino)hexamethylene), 2-(4-hydroxy-2
,2,6,6-tetramethyl-1-piperidyl]etha/
The effects of using the antioxidants mentioned above include hindered amine compounds such as condensates of dimethyl sulfate and dimethyl succinate.

This prevents deterioration of the resin due to high-temperature molding (although blending alone with an organic compound having a 2-benzofuranone skeleton has a sufficient effect), and particularly prevents deterioration over a long period of time, extending the life of the optical disc.

Furthermore, when a photostabilizer is used in combination, deterioration due to light is prevented.

Of course, antioxidants other than the above-mentioned specific examples and other well-known additives that are usually added to resins, such as lubricants, antistatic agents, slip agents, etc., may be added to the extent that they do not impair the purpose of the present invention. It will be obvious to those skilled in the art that this may be done.

In order to mold the optical disc of the present invention, first, a primary antioxidant is added to the resin for the optical disc and an organic compound having a 2-benzofuranone skeleton, if necessary.

A disk substrate is obtained by mixing a predetermined amount of a secondary antioxidant and the like and injection molding. More specifically, these are mixed using a ribbon blender, tumbler mixer, Henschel mixer, etc., or after mixing, they are melt-mixed using an extruder, Banbury mixer 1/2 roll, etc., or dissolved in a hydrocarbon or aromatic solvent. Single screw extruder, vented extruder, twin screw extruder, triple screw extruder, conical twin screw extruder, co-kneader, plateifier, mix) #- Dar%2m Funical Screw Extruder, Planetary Screw Extruder,
Injection molding is performed using a gear type extruder, screwless extruder, etc., and molding is performed using a mold for disc molding (including those equipped with a stamp bar for forming information bits and guide grooves). .

Various known gates may be used for injection molding, but in view of shrinkage and warping, center bin gates and center disc gates, preferably gate diameters of 5.
Center pin gate with a thickness of 1 mm or less, especially 0.5 to 2.0 mm, and a gate thickness of 1 mm or less, especially 0.2 to 0.8 m
It is better to use the center disc gate of m.

The disk substrate obtained by injection molding is then completed by forming a recording layer or a metal layer for reflecting laser beams by a known method such as vapor deposition or sputtering, and further providing a protective layer if necessary. .

Although injection molding has been described as a representative method for molding the optical disc of the present invention, other methods such as compression molding, lowlinks, and micromolding may also be used. In addition, it can be applied to systems that utilize organic dyes, crystal-amorphous phase changes, and systems that utilize magnetic materials such as ferrite.

The most suitable embodiment of the present invention is the case where PMP is used as the resin for optical discs. PMP is suitable as an optical disc substrate because it has excellent heat resistance, chemical resistance, solvent resistance, and water resistance. However, due to the high melting point of PMP itself, the temperature of the 512I form becomes extremely high.
Injection molding at high temperatures significantly accelerates the occurrence of voids, poor transferability, and silver streaks.
The mechanical properties also deteriorate significantly as the resin deteriorates. Therefore, PM
When the structure of the present invention is adopted for P, its effects are significantly exhibited, and as a result, a good disk substrate can be molded.

Here, ASTM D12 is used as PMP with high fluidity.
Load 5 & 9 according to 38. The melt flow rate measured at a temperature of 260°C is 50 g/10 m1n or more, especially 20
0g/10m1n or more, further 500g/IQ m
It is preferable that the number is 1n or more.

〔Example〕

Hereinafter, the content of the present invention will be explained using preferred examples.
The present invention is not limited to these examples unless otherwise specified.

Examples 1-2 and Comparative Examples 1-3 Melt flow rate at a load of 5 kg and a temperature of 260°C)
(MF'R: ASTM D 1238) is 2000g
/101IIir+ poly-4-methyl-1-pentene was blended with various stabilizers as shown in Table 1, and after mixing in a Henschel mixer, the screw diameter was 40LII1. 1 of l
Pellets were made using a axial extruder at a temperature of 240°C.

Using this pellet as raw material, each machine manufacturing company M 100Dt
Using an OA injection A-type machine and a gold 1F1 (mold equipped with a spunter for forming information pits) with a center disk gate (gate thickness 0.4 mm), it was made to a diameter of 120 mm and a thickness at the temperature shown in Table 1. A disk substrate of 1.2111111 was molded and the items shown in Table 1 were evaluated. These items are evaluated visually, and the evaluation standard is bad 1 →
It was rated 5 good.

The amount of the stabilizer is expressed in parts by weight based on 100 parts by weight of the raw material resin. The names of stabilizers indicated by abbreviations are:
It is shown in Table 2. Table 1 shows Examples and Comparative Examples.

〔Effect of the invention〕

The optical disc of the present invention has excellent mechanical properties even though it is molded at high temperatures, does not generate voids, can prevent silver streaks, and has extremely stable quality.

Claims (6)

[Claims] (1) An organic compound having an optionally substituted 2-benzofuranone skeleton having either at least one hydrogen atom or an organic group bonded by a double bond at the 3rd position is added to the resin for optical discs. Optical disc made by blending. (2) The optical disc according to claim 1, which contains a primary antioxidant and/or a secondary antioxidant. (3) The optical disc according to claim 2, wherein the primary antioxidant is a phenolic antioxidant. (4) The optical disc according to claim 2, wherein the secondary antioxidant is a phosphorus antioxidant. (5) The resin for optical discs is polymethyl methacrylate,
Polystyrene, polycarbonate and poly4-methyl-
5. The optical disc according to claim 1, wherein the optical disc is selected from the group consisting of 1-pentene. (6) The optical disc according to any one of claims 1 to 5, wherein the organic compound having a 2-benzofuranone skeleton is represented by the following formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (In the formula, R^1 and R^2 are hydrogen, optionally substituted alkyl, cycloalkyl, aryl, aralkyl,
Hydroxyl, halogen, carboxyl, 2-benzofuranone radicals, each of which may be the same or different, and which may be bonded by a double bond to alkylidene, cycloalkylidene, or arylalkylidene, which may alternatively be substituted together. , when not bonded by a double bond, either is hydrogen. R^3~R^6
is hydrogen, optionally substituted alkyl, cycloalkyl,
Aryl, aralkyl, alkoxy, alkyl or cycloalkyl or aryl or aralkyl or heterocyclocarbonyloxy, alkyl or cycloalkyl or aryl or aralkyl or alkoxy or aminocarbonyl, arylmercapto, carboxyl, hydroxy, halogen, nitro, -CH=O or a piperidine nucleus, a piperazine nucleus or a piperazinone nucleus-containing group, and further 2
-benzofuranone radicals, which may be the same or different, or two adjacent ones may mutually form a ring. )