JPH0692530B2 - Polycarbonate resin composition for optical disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a compact disk, a video disk, a write-once disk used for an optical recording / reproducing apparatus,
The present invention relates to a composition for a plastic high-density information recording carrier such as a disk for erasable direct read after-writing (E-DRAW), which shows the adhesion between a metal or metal oxide recording film or reflective film and a polycarbonate disk substrate. It is intended to provide a composition which is good and at the same time has excellent antistatic properties.

[Conventional technology]

Today, polycarbonate resin is used as a material for a plastic high-density information recording carrier substrate (hereinafter referred to as an optical disk substrate) used in optical recording and reproducing devices in terms of transparency, heat resistance, impact strength, hygroscopicity, and the like. It is becoming the most powerful.

In order to obtain readable information, a metal film such as a metal or a metal oxide, which reflects a laser beam or exhibits a physical change such as phase change or evaporation by the laser beam, is provided on the optical disk substrate.

In order to obtain a durable optical disc, it is important that the adhesion between the polycarbonate resin and the metal layer is good.

Further, since the optical disc is irradiated with a laser fine beam and the light amount of the reflected light is detected, the dust adhering to the surface of the optical disc scatters the reflected light and the like, so it is necessary to prevent the attachment of dust. Therefore, it is preferable to remove the charged electric charge in order to prevent the dust from being attracted to the disk by the electric charge.

As an antistatic method, it is easy to apply an antistatic agent to the surface of an optical disk, but there is a drawback that its performance is not permanent. Therefore, it is important to incorporate an antistatic agent inside the disk substrate.

Commonly used antistatic agents are bis (hydroxyethyl) alkylamine, sodium alkylbenzene sulfonate, etc. However, when manufacturing optical disc substrates made of polycarbonate by injection molding, polycarbonate is molded at a resin temperature of 320 to 400 ° C. To be done. When molded at such a high temperature, the above-mentioned antistatic agent decomposes itself or decomposes the polycarbonate and causes a defective appearance such as silver on the disk surface. In addition, these are the durability tests of the optical disc, which exposes the optical disc to high temperature and high humidity (for example, 50 ° C x 95% RH atmosphere) to corrode the metal film, causing pinholes and peeling. descend.

[Object of the Invention]

In view of the above circumstances, the present invention aims to provide an optical disk material having excellent durability and antistatic performance.

That is, the gist of the present invention is 100 parts by weight of a polycarbonate having a viscosity average molecular weight of 10,000 to 18,000, the general formula (R ¹ and R ⁴ are organic residues from a compound having a carboxyl group or a hydroxyl group, and R ² and R ³ represent a polyethylene glycol chain, a polypropylene glycol chain, or a copolymer chain of ethylene glycol and propylene glycol.) A phosphoric acid ester compound having a molecular weight of 500 to 5000
It is a polycarbonate resin composition for optical discs containing 0.01 to 5 parts by weight.

[Structure of Invention]

The present invention will be described in more detail. The aromatic polycarbonate resin used in the present invention is obtained by reacting various dihydroxydiaryl compounds with phosgene by a phosgene method, or by reacting dihydroxydiaryl compounds with a carbonic acid ester such as diphenyl carbonate. Polymers or copolymers obtained by the transesterification method, and a typical example thereof is a polycarbonate resin produced from 2,2-bis (4-hydroxyphenyl) propane (bisphenol A). To be

Examples of the dihydroxydiaryl compound include bisphenol A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2
-Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane , Bis (hydroxyaryl) alkanes such as 1,1-bis (4-hydroxy-3-tert-butylphenyl) propane, 1,1
-Bis (4-hydroxyphenyl) cyclopentane, 1,
Bis (hydroxyaryl) cycloalkanes such as 1-bis (4-hydroxyphenyl) cyclohexane,
4,4'-dihydroxydiphenyl ether, dihydroxydiaryl ethers such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4 ' -Dihydroxy-
Dihydroxydiaryl sulfides such as 3,3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3 '
-Dihydroxydiaryl sulfoxides such as dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone, dihydroxydiaryl sulfones such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, etc. .

These may be used alone or in combination of two or more,
In addition to these, piperazine, dipiperidyl, hydroquinone, resorcin, 4,4′-dihydroxydiphenyl and the like may be mixed and used.

From the point of birefringence, the molecular weight is 10,000 to 18,000,
It is more preferably 11,000 to 17,000. When the molecular weight is lower than this, the strength is low, and conversely, when the molecular weight is high, the birefringence does not become low.

The viscosity average molecular weight of the polycarbonate resin is 20 g using a 6.0 g / l methylene chloride solution of the polycarbonate resin.
From ηsp measured at And expression The value calculated by The average molecular weight is usually controlled by adding an end terminating agent such as phenol or p-tert-butylphenol at the time of producing a polycarbonate resin.

The phosphoric acid ester used in the present invention has the general formula (R ¹ and R ⁴ represent an organic residue, R ² and R ³ represent a polyethylene glycol chain, a polypropylene glycol chain, or a copolymer chain of ethylene glycol and propylene glycol.).

It is preferable that R ¹ and R ² and R ³ and R ⁴ are bonded via an ester bond or an ether bond, and accordingly R ¹ and R ⁴
R ⁴ is preferably a residue from a compound having a carboxyl group or a hydroxy group. Further, R ¹ and R ⁴ are preferably organic residues having a total of carbon or oxygen atoms of 3 or more. Therefore, acetic acid, propionic acid, acrylic acid, methacrylic acid, benzoic acid, cyclohexanecarboxylic acid, toluic acid, lauric acid, stearic acid, methyl alcohol, ethyl alcohol, propyl alcohol, octyl alcohol, lauryl alcohol, stearyl alcohol, phenol,
Groups derived from butylphenol, octylphenol, decylphenol, dodecylphenol and the like are used.

The molecular weight of the phosphate ester compound is 500-5000, and even 7
00 to 2500 is preferable. If it is smaller than this, the thermal stability is poor and problems occur during molding. On the other hand, if it is large, the compatibility with polycarbonate deteriorates and the transparency deteriorates. The number of added moles of glycol such as ethylene glycol is 3 to 10
0 is preferable, and 5 to 50 is more preferable.

Such a phosphoric acid ester compound is manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
More commercially available as New Frontier (trade name).

The blending amount of these phosphate ester compounds is 0.01 to 5 parts by weight, and further 0.0
A blend of 5 to 2 parts by weight is preferred. If the blending amount is smaller than this, there is no effect, and conversely, if the blending amount is large, the transparency is deteriorated.

As a method of blending the phosphoric acid ester compound with the polycarbonate resin, various methods can be used at any stage until just before the molding of the final molded product. The simplest method is to dry blend a polycarbonate resin and a phosphoric acid ester compound, but this dry blended product may be melt-mixed and extruded to form a pellet. Alternatively, a master pellet prepared by kneading an addition amount of a predetermined amount or more may be prepared and blended with a polycarbonate pellet for dilution.

Further, additives which are usually blended with polycarbonate and which do not adversely affect the performance as an optical disk substrate can be used. For example, trisnonylphenylphosphite, tris (2,4-di-t-butylphenyl) phosphite, cyclone neopentanetetraylbis (octadecylphosphite), 4,4'-butylidene-bis (3-methyl-6) -T-butylphenyl-di-tridecyl) phosphite and other phosphite-based heat stabilizers; 1,3,5
-Tris (3,5-di-t-butyl-4-hydroxy-benzyl) -S-triazine-2,4,6-trione, pentaerythrityl tetrakis [3- (4'-hydroxy-
3 ', 5'-di-t-butylphenyl) propionate], octadecyl- (4-hydroxy-3,5-di-t
And hindered phenol type antioxidants such as -butylphenyl) propionate; and fatty acid esters of glycerin, esters of fatty acids and aliphatic alcohols, paraffin wax, and releasing agents for bisamides. These are generally added in an amount of 0.005 to 0.5%, preferably 0.01 to 0.3%.

Injection molding and injection compression molding are used as the molding method for the optical disk substrate. The molding temperature is 300 to 420 ° C, and the mold temperature is from (Tg-20) ° C to (Tg-90) ° C. preferable. (Tg is the glass transition temperature of polycarbonate) The polycarbonate disk substrate used in the optical recording / reproducing apparatus of the composition of the present invention can be applied to any known recording / reproducing system. That is, when used as a read-only disc such as a compact disc or a laser disc, a reflective metal film such as aluminum is deposited on the substrate surface side, and in the case of a write-once disc, Al, Cr, Pb, Au, Rh, Zn, Cu, Sb, Te, In, Bi,
_{CS 2 -Te, Te-C,} Te-C, Te-As and the like, TeOx in the case of E-DRAW disks, Mn-Bi, Gd-Co , Tb-Fe, Tb-Gd
-Fe, Tb-Fe-Co, As-Se-S-Ge and the like are coated by a method such as vapor deposition, sputtering and ion plating. Generally, if necessary, a reflective metal film and a film of silicon oxide, epoxy, acrylic or the like are further formed for protection, and two discs may be bonded together.

〔Example〕

 The present invention will be described below with reference to examples.

In addition, "part" in an Example shows a "weight part."

Example 1, Comparative Examples 1 to 3 0.5 parts by weight of a phosphoric acid ester compound represented by the following structural formula and 100 parts by weight of a polycarbonate of 2,2-bis (4-hydroxyphenyl) propane having a viscosity average molecular weight of 15,000 and a heat stabilizer. Was mixed with 0.03 part by weight of trisnonyl phenyl phosphite (Mark 1178 manufactured by ADEKA ARGUS), and kneaded into a pellet at 230 ° C. with a 40φ vent extruder. After drying the pellets at 120 ℃, injection molding machine (M-100DM manufactured by Meiki)
A 120 mmφ compact disk was molded in. The molding conditions were a resin temperature of 340 ° C and a mold temperature of 85 ° C.

An aluminum layer having a thickness of about 200 nm was vacuum-deposited on the disk thus obtained, and an acrylic coating layer (thickness of about 15 μm) was applied thereon.

A heat cycle test was carried out in which the disk was repeatedly subjected to an atmosphere of high temperature and high humidity of 80 ° C. × 95% RH × 4 hrs and −40 ° C. × 4 hrs to test the adhesion between the Al film and the polycarbonate substrate.

In addition, static electricity is applied to the disk in a constant electrostatic field using the Statistic Neostometer (Shishido Shokai Co., Ltd.), and the time (half-life) at which the electrostatic charge decays to 1/2 is measured and the phosphoric acid ester compound is charged. The prevention performance was evaluated.

For comparison, one without a phosphate ester compound (Comparative Example 1) and one with another antistatic agent (Comparative Example 2,
3) is shown.

Other antistatic agents such as polyoxyethylene dodecylamine (L202 manufactured by NOF CORPORATION) and sodium dodecylbenzene sulfonate (NeoPerex manufactured by Kao Soap) were used. Silver was generated on the substrate surface.

The results are shown in Table-1.

[Advantages of the Invention] As described above, according to the present invention, an optical disk having good adhesion between the disk substrate and the recording film or the reflective film and excellent antistatic properties can be obtained.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area B29K 69:00

Claims (1)

[Claims] 1. A general formula for 100 parts by weight of a polycarbonate having a viscosity average molecular weight of 10,000 to 18,000 (R ¹ and R ⁴ are organic residues from a compound having a carboxyl group or a hydroxyl group, and R ² and R ³ represent a polyethylene glycol chain, a polypropylene glycol chain, or a copolymer chain of ethylene glycol and propylene glycol.) A polycarbonate resin composition for optical discs, containing 0.01 to 5 parts by weight of a phosphoric acid ester compound having a molecular weight of 500 to 5,000.