JPH1079142A - Method for abrading rear face of optical disk stamper and adhesive film used in the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for abrading a rear face of an optical disk stamper whereby a stamper surface is not contaminated and a word time can be shortened, and an adhesive film used in the method. SOLUTION: An adhesive film having an adhesive layer of a type set by ultraviolet rays is directly attached to a surface of an optical disk stamper, thereby to abrade a rear face of the stamper. The adhesive film has an average thickness of 20-300μm, a thickness dispersion of within ±5μm of the average thickness, an adhesive force (A) to a SUS304-BA plate of 10-2000g/25mm before irradiation with ultraviolet rays and an adhesive force (B) of 0-50g/25mm after irradiation with ultraviolet rays, with holding a relation of A>B. After the abrading, the adhesive film is irradiated with ultraviolet rays by 50-3000mJ/cm<2> before the film is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for polishing the back surface of a stamper for optical disks (the surface opposite to the surface on which the pits and grooves and / or grooves are formed), and an adhesive film used in the method. For more information, record information using light,
Manufacturing process and reproduction process of a stamper used for manufacturing an optical disk for reproducing and the like, and a magneto-optical disk for recording, reproducing and erasing information using light and magnetism (hereinafter collectively referred to as an optical disk) The present invention relates to a method for polishing the back surface of a stamper and the like, and an adhesive film used in the method. More specifically, when the back surface of the stamper is polished in a manufacturing process, a reproduction processing process, and the like of the optical disk stamper, the pit and / or groove uneven surface of the optical disk stamper (hereinafter, referred to as a stamper) is formed. (Hereinafter referred to as signal uneven surface or stamper surface) a method of directly affixing an adhesive film to the back surface of the stamper while protecting the signal uneven surface.
And an adhesive film used in the method.

[0002]

2. Description of the Related Art An optical disk on which information is recorded, reproduced, and erased by using light or light and magnetism is used as an injection molding method, a compression molding method, an injection compression molding method, a photosensitive molding method using a stamper as a molding die. An optical disk substrate having pits and grooves formed on one side is manufactured by a method such as a reactive resin method (2P method), and a metal reflective layer, a protective layer, and the like are formed on this surface. Write-once or rewritable optical (magnetic) disks (CD
In the case of (-R, MO, etc.), a storage film made of an inorganic material such as an organic dye, a magnetic material, an alloy, or a metal oxide is formed between the substrate and the metal reflective layer, the protective layer, or the like. In general, pits refer to holes for recording signals for reproducing audio, video, information, etc., as well as address information and information for indicating the characteristics of a disc, and grooves refer to write-once and rewritable types. A guide groove for recording a signal used in the case of an optical (magnetic) disk.

Usually, in a stamper manufacturing process, first, a recording master is prepared. As the master, a glass material with high surface accuracy is used. Next, a photoresist film as a photosensitive material is formed on the polished master. The photosensitive film is exposed by a laser beam to cut necessary information. When the cutting is completed, development is performed and signal irregularities are formed on the glass master. Next, after the signal unevenness forming surface is converted to a conductor, a metal (usually Ni is used) master is formed by electroforming, and information is copied from the glass master. The metal master is peeled off from the glass master, the back surface thereof is polished, the inner and outer diameters are processed, and the stamper is cut to a predetermined size. In general, in the case of the read-only type, information is copied as pits and projections, and in the case of the write-once type and rewritable type, information is copied as pits and grooves.

When an optical disk substrate is manufactured by using a stamper as a mold by, for example, an injection molding method, a compression molding method, an injection compression molding method, or the like, the back surface of the stamper is made smooth to minimize the surface roughness of the back surface. The back surface must be sufficiently polished so that the thickness becomes uniform. This is because, for example, during injection (compression) molding, a resin pressure of about 400 to 600 kg / cm ² is applied, so that the effects of the surface roughness of the back surface of the stamper and the nonuniformity of the stamper thickness directly appear on the surface state of the stamper. This is because it greatly affects the characteristics of the resin substrate to be transferred. Therefore, when polishing the back surface of the stamper in the manufacturing process of the stamper, it is necessary to protect the signal uneven surface.

When an optical disk substrate is manufactured by an injection molding method, a compression molding method, an injection compression molding method, or the like using a stamper whose back surface is sufficiently polished as described above,
If 0 to 20,000 sheets (depending on the manufacturing conditions) are manufactured, the surface state of the back surface of the stamper (hereinafter referred to as the back surface state) deteriorates due to the raw material resin wrapping around the back surface of the stamper and impact on the back surface of the stamper. The characteristics of the resulting disk substrate deteriorate. Therefore, it is necessary to re-grind the back surface of the stamper to regenerate the stamper. Even when the back surface of the stamper having such deteriorated back surface condition is polished and reworked, it is necessary to protect the signal uneven surface. Also, when the stamper is stored after manufacturing, after use, or the like, the signal uneven surface is protected.

[0006] Conventionally, as a method of protecting the surface on which signal irregularities are formed during the production, reproduction, or storage of a stamper, a metal stamper, which is an object to be polished, is disclosed in Japanese Patent Application Laid-Open No. 60-216915. Larger than the outer diameter of the release auxiliary sheet having a uniform thickness is disposed at the center of the disk-shaped metal plate, and a double-sided adhesive sheet is attached to the disk-shaped metal plate surface so as to cover the release auxiliary sheet, and the signal surface is provided. After the metal stamper coated with the protective coating is fixed on the double-sided pressure-sensitive adhesive sheet so that the signal side of the metal stamper corresponds to the double-sided pressure-sensitive adhesive sheet, a metal stamper rear-surface polishing method of polishing the rear surface of the metal stamper by a polishing method or a lapping method, A protective film is provided on the surface of a stamper which has been subjected to an electroforming process and disclosed in Japanese Unexamined Patent Publication No. 63-247932, and the surface having this protective film faces the substrate. In the manufacture of a stamper having a step of bonding the stamper and the substrate by using a stamper, the stamper is used which has been processed to be 10 mm or more in diameter and finally larger than the intended outer diameter, and the outer diameter of the stamper is increased. In accordance with a method of manufacturing a stamper, in which a portion lacking the protective film is provided in the portion, and the missing portion is used for adhesion to the substrate, the signal uneven surface of the stamper A method of protecting with a protective layer was performed.

However, since these protective layers are formed by applying and drying a solution of a polymer by a spin coating method or the like, various problems have occurred. For example, (1) the polymer solution contains an organic solvent, and a problem that a large-scale local exhaust system must be provided (usually, a polymer protective layer is formed in a clean room to maintain the cleanliness of the stamper). Therefore, it is not practical to provide a large-scale local exhaust system in a clean room). (2) The polymer protective layer is difficult to completely remove even when washed with an organic solvent, and often remains in a trace amount, thereby causing contamination of the stamper.
(3) The problem of managing the solution in order to satisfy the required properties of the protective layer (thickness uniformity, cleanliness that does not include contamination to leave no defect on the surface for forming signal irregularities) (filtering a polymer solution with a filter). And maintaining the viscosity of the polymer solution in a predetermined range). (4) Problems of workability (a long time is required for application, drying and curing of a solution to form a polymer protective layer). Furthermore, if the film shrinks during the formation of the protective layer, warping of the stamper itself may be a problem.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have intensively studied a method of polishing the back surface of a stamper for an optical disc which does not contaminate the surface of the stamper, shortens the working time, and is free from environmental pollution by an organic solvent. Then, a method for directly affixing a specific adhesive film to the pit unevenness and / or groove unevenness forming surface of the optical disk stamper to polish the back surface of the stamper and a technique relating to the adhesive film used in the method were completed. Patent applications for such inventions have already been filed as Japanese Patent Application Nos. 8-190484 and 8-198658.

The pressure-sensitive adhesive film related to the above patent application is S
The adhesive strength to US304-BA plate is 10 to 180 g /
It is in the range of 25 mm. Since the surface state of the stamper for an optical disk varies widely, the adhesive strength described above may cause problems in adhesiveness and peeling property, and it has been found that it is not always sufficient to reduce the working time. For example, there are cases where the protection of the stamper is insufficient when polishing the back surface, or the peeling workability after polishing the back surface is insufficient.

In view of the above problems, it is an object of the present invention to provide a method of polishing the back surface of a stamper for an optical disc which does not contaminate the surface of the stamper and does not cause environmental pollution by an organic solvent, and an adhesive film used in the method. An object of the present invention is to provide a method capable of further reducing the working time.

[0011]

The present inventors have conducted intensive studies and as a result, have found that when polishing the back surface of an optical disk stamper,
When the pressure-sensitive adhesive film is directly adhered to the signal uneven surface of the stamper through the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive surface, the pressure-sensitive adhesive film is formed by forming the pressure-sensitive adhesive layer with an ultraviolet-curable pressure-sensitive adhesive, and polishing the back surface of the stamper. It has been found that the above object can be achieved by irradiating ultraviolet rays before peeling off, and the present invention has been accomplished.

That is, according to the present invention, an adhesive film is directly attached to a surface of a stamper for an optical disc on which pits and / or grooves are formed, and the back surface of the stamper is polished.
A method of polishing the back surface of an optical disc stamper that peels off the pressure-sensitive adhesive film after polishing is completed, wherein the pressure-sensitive adhesive film comprises a UV-transmitting substrate film and a UV-curable pressure-sensitive adhesive layer formed on one surface thereof, Average thickness 20-3
00 μm, the thickness variation is within ± 5 μm of the average thickness, and the adhesive strength to the SUS304-BA plate is 10 to 2000 g / 25 mm before (A) and 0 to 50 g / 25 mm (B) after ultraviolet irradiation (B). However, A> B)
After the polishing of the back surface of the stamper, before the adhesive film is peeled off, the adhesive film is subjected to 50 to 3000 mJ / cm.
^2. A method of polishing the back surface of an optical disk stamper, which is characterized by irradiating the ultraviolet light of ( ² ), and an adhesive film used in the method.

A feature of the present invention is that a pressure-sensitive adhesive film having an ultraviolet-curable pressure-sensitive adhesive layer is directly adhered to the signal uneven surface (front surface) of the stamper via the pressure-sensitive adhesive layer, and the back surface of the stamper is polished. Then, a specific amount of ultraviolet light is irradiated before the adhesive film is peeled off. The second feature is that the adhesive strength before and after the irradiation of ultraviolet rays, the thickness of the adhesive film, the variation thereof, and the like are limited to specific ranges.

The pressure-sensitive adhesive film for polishing the back surface of the stamper for an optical disk of the present invention is cured by irradiating a specific amount of ultraviolet rays from the substrate film side at the time of peeling, whereby the pressure-sensitive adhesive layer is cured and the adhesive force at the time of peeling is a specific value. Down to the range,
After the peeling, no contamination due to the pressure-sensitive adhesive layer remains, the stamper is not deformed by the peeling stress, and the peeling workability is further improved (especially, shortened). In addition, when the back surface of the stamper is polished, the stamper is strongly adhered, and damage to the stamper during polishing and contamination of the signal irregularity forming surface can be prevented. Further, since the thickness variation of the pressure-sensitive adhesive film is limited to a specific range, the thickness variation of the obtained stamper can be suppressed to a usable range.

Further, there is no need to form a protective layer by spin coating a polymer solution on the signal uneven surface of the stamper. Therefore, solution application for forming a protective layer,
Drying work and the like can be omitted, and work time can be greatly reduced. Since there is no generation of organic solvent gas when drying the applied polymer solution, there is no risk of polluting the environment. Therefore, according to the present invention, it is possible to improve workability in the manufacturing process of the stamper for an optical disc, prevent environmental pollution, and the like.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The optical disk stamper according to the present invention is not limited to a stamper used for manufacturing a read-only optical disk capable of reproducing information using light, such as a compact disk (CD) and a video disk (LD). It also includes a stamper used for manufacturing a write-once or rewritable optical disk, a magneto-optical disk, or the like, which can record, reproduce, and erase information using light or light and magnetism. In addition, the polishing of the back surface of the stamper for an optical disc in the present invention includes not only the polishing of the back surface when a stamper for an optical disc is newly manufactured, but also the polishing of the back surface when performing a reproduction process.

According to the present invention, when polishing the back surface of the stamper for an optical disk, an ultraviolet-curable pressure-sensitive adhesive layer is formed on one surface of a UV-permeable base film, and if necessary, the pressure-sensitive adhesive layer is A specific adhesive film having a release film disposed on the surface (the release film is peeled off when applied) is attached to the signal unevenness forming surface of the stamper via the adhesive layer surface, and the back surface is polished, A method of polishing a back surface of a stamper, which comprises irradiating a specific amount of ultraviolet light after the back surface polishing and then peeling the film, and an adhesive film used in the method.

First, the method for polishing the back surface of the stamper for an optical disk of the present invention will be described. A stamper before processing having signal irregularities on the surface is manufactured by a series of steps. The release film is peeled off from the surface of the adhesive layer of the adhesive film for polishing the back surface of the stamper for an optical disc (hereinafter, referred to as an adhesive film), and the surface of the adhesive layer is exposed, and the stamper before the back surface polishing is processed through the adhesive layer. Adhere on the uneven surface. Next, the stamper is fixed to the polishing jig board through the base film layer of the adhesive film using a vacuum device or the like, and the back surface of the stamper is polished. After polishing, the adhesive film is irradiated with a specific amount of ultraviolet light from the base film side of the adhesive film, and then the adhesive film is peeled off. After the peeling, a cleaning process such as water cleaning or plasma cleaning may be performed on the signal concavo-convex formation surface as needed. Further, the adhesive film may be stored for a certain period without being peeled off.

The irradiation amount of the ultraviolet ray may be the same as that when using a known adhesive film having a property that the adhesive strength is reduced by the irradiation of the ultraviolet ray (Japanese Patent Publication No. 58-50164, etc.).
If more specifically exemplified, usually 50-3000m
J / cm ² [Time (second) is applied to the ultraviolet illuminance (mW / cm ² ) measured using a digital indicating ultraviolet illuminometer UV-M02 (receiver: UV-35) manufactured by Oak Manufacturing Co., Ltd. Value]. If the irradiation amount is small, the adhesive strength tends to be insufficiently reduced, it is difficult to peel off without deforming the stamper, and the workability tends to be reduced. If the amount is large, the adhesive film may be deformed (shrinkage or the like) by heat at the time of irradiation, and the stamper may be deformed accordingly.

In order to obtain the above irradiation amount, usually, 10
UV light of １０００1000 mW / cm ² [value measured using a digital indicating type UV illuminometer UV-M02 (receiver: UV-35) manufactured by Oak Manufacturing Co., Ltd.]
Usually, irradiation is preferably performed for about 1 to 30 seconds so that the irradiation amount falls within the above range. Various known devices can be used as the source of the ultraviolet light, but typical examples include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a pulse xenon lamp, and an electrodeless discharge. Lamps and the like.

After the polishing, the inner and outer diameters may be processed with a lathe or the like while the adhesive film is adhered. The process of processing the inner and outer diameters may be performed before polishing the back surface, in which case,
An adhesive film may be adhered from the time of processing the inner and outer diameters, and after the processing, the back surface may be continuously polished with the adhesive film adhered. The backside polishing method using the pressure-sensitive adhesive film of the present invention is not particularly limited, and a known polishing method may be used.

The pressure-sensitive adhesive film of the present invention can be used not only for polishing the back surface during the manufacture of the stamper as described above, but also for reclaiming the back surface of the stamper, which has become unusable due to the deterioration of the back surface during the manufacture of the optical disk substrate. It can also be used for processing, or simply protecting the signal uneven surface when storing the stamper.

Next, the pressure-sensitive adhesive film of the present invention will be described. The pressure-sensitive adhesive film of the present invention is a solution or emulsion containing a UV-curable pressure-sensitive adhesive on one surface of a UV-permeable base film (hereinafter, simply referred to as a base film) or a release film. Pressure-sensitive adhesive coating solution) and dried to form a pressure-sensitive adhesive layer.

When a pressure-sensitive adhesive layer is formed on a substrate film, it is preferable to attach a release film to the surface of the pressure-sensitive adhesive layer in order to protect it from contamination due to the environment. In the case where an adhesive layer is formed on one surface of the release film, a method of transferring the adhesive layer to a base film is employed. Whether to apply the pressure-sensitive adhesive coating solution to one surface of the base film or the release film is determined in consideration of the heat resistance of the base film and the release film, the contamination of the signal unevenness forming surface of the optical disc stamper, and the like. Decide. For example, when the heat resistance of the release film is superior to that of the base film, an adhesive layer is provided on the surface of the release film and then transferred to the base film. When the heat resistance is the same or the base film is excellent, an adhesive layer is provided on the surface of the base film, and a release film is attached to the surface of the adhesive layer.

Considering that the pressure-sensitive adhesive film of the present invention is adhered to the signal uneven surface of the stamper via the surface of the pressure-sensitive adhesive layer exposed when the release film is peeled off, information recording by the pressure-sensitive adhesive layer is considered. In order to prevent surface contamination, use a release film with good heat resistance, apply an adhesive coating solution on the surface, dry it to form an adhesive layer, and transfer it to the base film Is preferred.

The base film of the pressure-sensitive adhesive film of the present invention may be a film made of synthetic resin, natural rubber, synthetic rubber or the like and having a property of transmitting ultraviolet light. If specifically exemplified, polyethylene, polyolefins such as polypropylene, polyesters, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, polybutadiene, soft vinyl chloride resin, polyamide, resins such as ionomer, and the like. Copolymer elastomers and films such as diene-based, nitrile-based, silicone-based, and acrylic-based synthetic rubbers are exemplified. The base film may be a single layer or a laminate.

The thickness of the base film is the sum of the thickness of the pressure-sensitive adhesive layer described later, that is, the thickness of the pressure-sensitive adhesive film is 20 to 30.
It is preferable to select the thickness to be 0 μm. A more preferred thickness of the pressure-sensitive adhesive film is 25 to 200 μm. The thickness of the pressure-sensitive adhesive film affects prevention of breakage of the stamper in the stamper back surface polishing step, workability of attaching and detaching the stamper to the signal unevenness forming surface, production cost of the pressure-sensitive adhesive film, and the like. When the thickness is reduced, the workability and the ability to protect the signal surface of the stamper tend to decrease, and when the thickness is increased, the production cost of the adhesive film tends to increase.

It is preferable that the substrate film is manufactured by controlling the thickness variation so as not to affect the thickness variation of the pressure-sensitive adhesive film described later. In order to improve the adhesive strength between the substrate film and the pressure-sensitive adhesive layer, it is preferable to subject the surface of the substrate film on which the pressure-sensitive adhesive layer is provided to a corona discharge treatment or a chemical treatment. An undercoat may be used between the base film and the pressure-sensitive adhesive layer.

When the release film is peeled off from the adhesive film, the workability is reduced due to static electricity generated when the adhesive film is peeled off from the stamper, or external contaminants adhere to the signal uneven surface of the stamper. In consideration of the fact that it becomes easier, it is preferable to perform an antistatic treatment on the surface of the base film opposite to the pressure-sensitive adhesive layer. Examples of the antistatic treatment method include a method of applying an antistatic agent such as a surfactant, a method of performing corona discharge treatment, and the like.

The substrate film has a thickness of 320 nm to 40 nm.
30% light transmittance at at least some wavelengths of 0 nm
It is preferable that it is above. More preferably, it is 60% or more. When the light transmittance is large, the adhesive strength after irradiation with ultraviolet rays tends to decrease, and when the light transmittance is small, the adhesive strength tends to decrease.

The pressure-sensitive adhesive film of the present invention may be provided on a surface opposite to the pressure-sensitive adhesive layer (for protecting the uneven surface for a stamper signal) of a base film according to a back surface polishing method or a polishing device. A separate pressure-sensitive adhesive layer may be provided for fixing the adhesive layer. In this case, it is not necessary to provide a fixing device such as a vacuum suction device in the polishing device. However, when the pressure-sensitive adhesive layer for fixing to the polishing apparatus is provided, it is preferable to provide the pressure-sensitive adhesive layer so that the thickness variation of the entire pressure-sensitive adhesive film falls within a preferable range described later. Further, it is preferable that the adhesive strength between the fixing pressure-sensitive adhesive layer and the processing jig board is adjusted so that the stamper can be peeled off without being deformed after the polishing. For example, an easy peeling process is performed on the jig board side.

Examples of the release film of the pressure-sensitive adhesive film of the present invention include synthetic resin films such as polypropylene and polyethylene terephthalate. Preferably, the surface thereof is subjected to a silicone treatment or the like as necessary. The thickness of the release film is usually from 10 to 150 μm. Preferably it is 30 to 100 μm.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is formed by applying a pressure-sensitive adhesive coating solution to one surface of a base film or a release film and drying. The pressure-sensitive adhesive application liquid is a solution or an emulsion liquid containing a UV-curable pressure-sensitive adhesive.

As the UV-curable pressure-sensitive adhesive constituting the UV-curable pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention, various known structures can be used as long as the pressure-sensitive adhesive properties described below are adjusted within the range of the present application. Things are adopted. For example, those containing an adhesive polymer, a photopolymerization initiator, a monomer and / or oligomer having a polymerizable carbon-carbon double bond in the molecule, and, if necessary, a thermal crosslinking agent are preferably used.

Hereinafter, the ultraviolet-curable pressure-sensitive adhesive having the above structure will be described in detail. Examples of the pressure-sensitive adhesive polymer include various synthetic rubber polymers such as an alkyl acrylate polymer, an alkyl methacrylate polymer, a butadiene polymer, an isoprene polymer, a styrene-butadiene polymer, and a polyester polymer. Of these, alkyl acrylate polymers and alkyl methacrylate polymers (hereinafter collectively referred to as alkyl acrylate polymers) are preferred in view of reproducibility and the like.

When the pressure-sensitive adhesive polymer is an alkyl acrylate polymer, the main monomers constituting the polymer are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylic Examples thereof include alkyl acrylates such as 2-ethylhexyl acid and 2-ethylhexyl methacrylate, and alkyl methacrylates. These may be used alone or. Two or more kinds may be used as a mixture. It is preferable that the amount of the main monomer used is usually in the range of 60 to 99% by weight in the total amount of all the monomers used as the raw material of the pressure-sensitive adhesive polymer. A comonomer having a polymerizable double bond such as vinyl acetate, acrylonitrile, and styrene may be appropriately copolymerized with these main monomers.

When a thermal crosslinking agent described later is used, the pressure-sensitive adhesive polymer needs to have a functional group capable of crosslinking with the thermal crosslinking agent. In this case, a comonomer having the functional group is copolymerized, or a functional group generated by a polymer reaction (double bond introduction reaction) described later is used as a functional group capable of performing a cross-linking reaction. Examples of the former comonomer having the functional group include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkyl ester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester, Monoalkyl fumarate, monoalkyl maleate, 2-hydroxyethyl acrylate,
Examples include 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, tert-butylaminoethyl methacrylate, and the like. One of these may be copolymerized with the above main monomer, or two or more thereof may be copolymerized. The amount used when copolymerizing a comonomer having a functional group capable of reacting with the crosslinking agent is usually 1 to 40 in the total amount of all monomers to be used as a raw material of the pressure-sensitive adhesive polymer.
% By weight.

Further, if necessary, glycidyl acrylate, glycidyl methacrylate, isocyanate ethyl acrylate, isocyanate ethyl methacrylate,
-(1-aziridinyl) ethyl acrylate, 2- (1
Monomers having a self-crosslinkable functional group such as -aziridinyl) ethyl methacrylate, monomers having a polymerizable double bond such as vinyl acetate, acrylonitrile, and styrene;
Polyfunctional monomers such as divinylbenzene, vinyl acrylate, vinyl methacrylate, allyl acrylate and allyl methacrylate may be copolymerized.

The pressure-sensitive adhesive polymer may have a polymerizable carbon-carbon double bond in the molecule. When a pressure-sensitive adhesive polymer having a polymerizable carbon-carbon double bond in the molecule is used, the amount of a monomer and / or oligomer having a polymerizable carbon-carbon double bond described below is added. May be reduced), which is preferable.

There are various known methods for synthesizing a pressure-sensitive adhesive polymer having a polymerizable carbon-carbon double bond in the molecule. For example, a monomer having a carboxyl group such as acrylic acid and methacrylic acid is copolymerized with the main monomer and the like, and after polymerization, glycidyl acrylate having an epoxy group capable of undergoing an addition reaction with a carboxyl group in the obtained polymer, methacrylic acid A method of reacting a monomer such as glycidyl. Or, conversely, a method in which monomers such as glycidyl acrylate and glycidyl methacrylate are copolymerized, and an epoxy group in the polymer obtained after the polymerization is reacted with an acrylic acid and a carboxyl group such as methacrylic acid.
A method in which a monomer having a functional group capable of undergoing an addition reaction with a functional group in a polymer is subjected to an addition reaction while leaving a polymerizable carbon-carbon double bond on a polymer obtained by copolymerizing a monomer having an addition-reactive functional group, etc. Is mentioned. The combination of these functional groups is a carboxyl group and an epoxy group, a carboxyl group and an aziridinyl group, a hydroxyl group and an isocyanate group,
A combination in which an addition reaction easily occurs is desirable. The reaction is not limited to an addition reaction, and any reaction may be used as long as a polymerizable carbon-carbon double bond can be easily introduced, such as a condensation reaction between a carboxyl group and a hydroxyl group.

As described above, a polymer having a functional group and a monomer having a functional group capable of undergoing an addition reaction with a functional group in the polymer have a polymerizable carbon-carbon double bond in the molecule. In addition to the method of synthesizing the pressure-sensitive adhesive polymer, a polyfunctional monomer having two or more polymerizable carbon-carbon double bonds in the molecule is copolymerized with the main monomer and the like, and at this time, the polymerization reaction is controlled. However, it can also be synthesized by terminating the polymerization while leaving a part of the polymerizable carbon-carbon double bond in the polyfunctional monomer. Examples of such polyfunctional monomers include the above-mentioned divinylbenzene, vinyl acrylate, vinyl methacrylate, allyl acrylate, allyl methacrylate, and the like.

The photopolymerization initiator constituting the ultraviolet-curable pressure-sensitive adhesive has a property of generating radicals by ultraviolet rays,
It is used for initiating an ultraviolet curing reaction of the pressure-sensitive adhesive layer. Specific examples include benzoin (Nissocure BO, manufactured by Nippon Soda Co., Ltd.) and benzoin methyl ether [Nissocure MB, manufactured by Nippon Soda Co., Ltd.]
O, etc.), benzoin ethyl ether [Nippon Soda Co., Ltd.
Manufactured by Nissocure EBO, etc.), benzoin isopropyl ether [Nissocure IB manufactured by Nippon Soda Co., Ltd.]
PO, etc.), benzoin isobutyl ether, benzyl dimethyl ketal [Nippon Ciba Geigy Co., Ltd., Irgacure-651, etc.], 1-hydroxycyclohexyl phenyl ketone [Nippon Ciba Geigy Co., Ltd., Irgacure-184, etc.], 2-methyl-1
-[4- (methylthio) phenyl] -2-monophorinopropane-1 [Nippon Ciba-Geigy Co., Ltd., Irgacure-
907, etc.], diethoxyacetophenone, 4- (2-
Hydroxyethoxy) -phenyl (2-hydroxy-2
Acetophenones such as -propyl) ketone [Merck Japan K.K., Darocure-2959, etc.], benzophenones [Kayacure BP, etc., manufactured by Nippon Kayaku Co., Ltd.], benzophenones such as hydroxybenzophenone, thioxanthone [Nippon Soda ( Co., Ltd., Nissocure TX,
Etc.], 2-methylthioxanthone [produced by Nippon Soda Co., Ltd.
Nissocure MTX, etc.), 2,4-diethylthioxanthone [manufactured by Nippon Kayaku Co., Ltd., Kayacure DETX,
Etc.], benzyl, anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone and the like. These may be used alone or in combination of two or more. The content is usually 0.1 to 1 with respect to 100 parts by weight of the pressure-sensitive adhesive polymer.
5 parts by weight. Preferably, it is 1 to 10 parts by weight.
If the content is large, the surface of the stamper tends to be contaminated, and if the content is small, the adhesive strength after ultraviolet curing tends to be insufficient.

The ultraviolet-curable pressure-sensitive adhesive used in the present invention may contain, if necessary, a photoinitiator in order to accelerate the reaction, in addition to the above-mentioned photopolymerization initiator. Examples of the photoinitiating aid include triethanolamine, methyldiethanolamine, 2-dimethylaminoethylbenzoic acid, and ethyl 4-dimethylaminobenzoate (Kayacure EPA, manufactured by Nippon Kayaku Co., Ltd.). These photoinitiating aids may be used alone or in combination of two or more. Usually, the content is preferably such that the sum with the photoinitiator is within the range of the content of the photoinitiator.

The monomer and / or oligomer having a polymerizable carbon-carbon double bond in the molecule constituting the ultraviolet-curable pressure-sensitive adhesive is polymerized at the time of irradiation with ultraviolet light to cure the pressure-sensitive adhesive layer and reduce the adhesive strength. used. Specifically, urethane (meth) acrylate oligomer, epoxy (meth) acrylate oligomer, polyester (meth) acrylate oligomer, bis (acryloxyethyl) hydroxyethyl isocyanurate, bis (methacryloxyethyl) hydroxyethyl Isocyanurate, tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, bisphenol A di (meth) acrylate,
Bisphenol F di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate ) Various modifications of acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (methacryloxyethyl) isocyanurate, tris (acryloxyethyl) Various modified isocyanurates, various modified bisphenol A di (meth) acrylates, various modified bisphenol F di (meth) acrylates, trimethylo Various modified products of tri (meth) acrylate, various modified products of dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more. Here, the description of (meth) acrylic acid and (meth) acrylate means acrylic acid and methacrylic acid, and acrylate and methacrylate.

The content is usually 1 to 100 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive polymer. If the content is high, the stamper surface may be contaminated, and if the content is low, the adhesive strength after ultraviolet curing tends to be insufficient.

When the pressure-sensitive adhesive polymer has a polymerizable carbon-carbon double bond in the molecule, the content of the monomer and / or oligomer may be small, and the pressure-sensitive adhesive polymer has a polymerizable carbon-carbon double bond in the molecule. -The content of the monomer and / or oligomer depends on the amount of the carbon double bond and the properties of the pressure-sensitive adhesive polymer such as Tg, the type and amount of the photopolymerization initiator to be combined, and the characteristics required for the pressure-sensitive adhesive film. The amount may be less than 1 part by weight (including 0 part by weight) based on 100 parts by weight of the pressure-sensitive adhesive polymer.

The thermal crosslinking agent optionally contained in the ultraviolet-curable pressure-sensitive adhesive contains two or more crosslinking reactive functional groups in one molecule.
These compounds are used to adjust the adhesive force of the adhesive film and the cohesive force of the adhesive layer by causing a crosslinking reaction with the functional group of the adhesive polymer. As the thermal crosslinking agent, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether,
Epoxy compounds such as neopentyl glycol diglycidyl ether and resorcin diglycidyl ether, isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate 3 adduct of trimethylolpropane, polyisocyanate, and trimethylolpropane-tri- β-aziridinyl propionate, tetramethylolmethane
Tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-
Bis (1-aziridinecarboxamide), N, N'-
Aziridine compounds such as toluene-2,4-bis (1-aziridinecarboxamide) and trimethylolpropane-tri-β- (2-methylaziridine) propionate; and melamine compounds such as hexamethoxymethylolmelamine. .

These may be used alone or in combination of two or more. Among the above thermal crosslinking agents, the epoxy crosslinking agent has a slow crosslinking reaction speed, and when the reaction does not proceed sufficiently, the cohesive force of the pressure-sensitive adhesive layer decreases, and depending on the state of the stamper surface, the polishing method, etc. Contamination due to the agent layer may occur. Therefore, as appropriate, a catalyst such as an amine is added, or a monomer having an amine functional group having a catalytic action is copolymerized with an adhesive polymer, or an aziridine-based compound having an amine property when a crosslinking agent is used. It is preferable to use a crosslinking agent together.

In general, when a thermal crosslinking agent is contained in the pressure-sensitive adhesive layer, a crosslinking reaction occurs with a functional group of the pressure-sensitive adhesive polymer, so that the signal-forming uneven surface of the stamper caused by the pressure-sensitive adhesive layer is hardly contaminated. Effect. In the present invention, after polishing the back surface of the stamper, before peeling the pressure-sensitive adhesive film, by irradiating ultraviolet rays from the base film side, the pressure-sensitive adhesive layer is cured by photopolymerization, and does not contaminate the stamper surface. It is characterized by. However, polymerization inhibition by oxygen and contaminants such as polishing dust adhere to the base film,
In consideration of the possibility that ultraviolet rays do not sufficiently reach the pressure-sensitive adhesive layer, for some reason, polymerization may not partially proceed and curing may be insufficient, the pressure-sensitive adhesive layer contains a thermal crosslinking agent Is preferred.

When a thermal crosslinking agent is used, its content is
Usually, it is contained in such a range that the number of functional groups in the crosslinking agent does not become larger than the number of functional groups in the pressure-sensitive adhesive polymer. However, when a new functional group is generated by the crosslinking reaction, or when the crosslinking reaction is slow, it may be contained in excess, if necessary.
The content of the crosslinking agent is preferably 0.1 to 30 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive polymer.

The ultraviolet-curable pressure-sensitive adhesive of the present invention comprises the above pressure-sensitive adhesive polymer, a photopolymerization initiator, a monomer and / or oligomer having a polymerizable carbon-carbon double bond in the molecule,
In addition to a thermal cross-linking agent, if necessary, a polymerization inhibitor such as phenothiazine or hydroquinone for improving the storage stability of the pressure-sensitive adhesive layer, a rosin-based or terpene resin-based tack for adjusting the adhesive properties. A fire may be appropriately contained. When the pressure-sensitive adhesive coating liquid is an emulsion liquid, it may contain a film-forming auxiliary such as diethylene glycol monoalkyl ether.

The UV-curable pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is obtained by applying a pressure-sensitive adhesive coating solution containing a UV-curable pressure-sensitive adhesive having the above-mentioned structure to a base film and / or a release film, and drying. The thickness is determined in consideration of the conditions for polishing the back surface, the type of stamper, and the like. Usually, it is preferably in the range of 2 to 15 μm, more preferably in the range of 2 to 10 μm.

As a method for applying the pressure-sensitive adhesive coating solution to one surface of the base film or the release film, a conventionally known coating method, for example, a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coat method A coater method, a die coater method, or the like can be employed. The drying condition of the applied pressure-sensitive adhesive is not particularly limited, but generally, 8
It is preferable to dry in a temperature range of 0 to 200 ° C. for 10 seconds to 10 minutes. More preferably 80 to 170 ° C
For 15 seconds to 5 minutes.

The variation in the thickness of the pressure-sensitive adhesive film particularly affects the variation in the thickness of the stamper after the back polishing process (at the time of manufacturing or at the time of regenerating). Therefore, the thickness variation of the pressure-sensitive adhesive film is preferably within ± 5 μm with respect to the average value of the thickness. More preferably, it is within ± 3 μm.

In the production of the pressure-sensitive adhesive film of the present invention, after the drying of the pressure-sensitive adhesive coating solution is completed, the pressure-sensitive adhesive film is heated at 40 to 80 ° C. in order to sufficiently promote the cross-linking reaction between the cross-linking agent and the pressure-sensitive adhesive polymer. It may be heated for about 5 to 300 hours.

In the present invention, the adhesive strength of the adhesive film affects, for example, the protective properties of the stamper on the signal irregularity forming surface, the workability of peeling from the stamper, and the like. Protective properties of the stamper's signal uneven surface (particularly, prevention of intrusion of abrasives and polishing debris during backside polishing), and handling workability of the stamper to which the adhesive film is attached (the adhesive film does not peel off during handling) In consideration of (1) and the like, a higher value is preferable within a range of 10 g / 25 mm or more in terms of the adhesive strength to the SUS-304BA plate. However, at the time of peeling, if the adhesive strength (that is, the adhesive strength after irradiation with ultraviolet rays) is high, it is difficult to peel without deformation, and the peeling operation time tends to be long, and the stamper is deformed by the peeling stress. In some cases (generally, if it exceeds 180 g / 25 mm in terms of adhesive strength to a SUS-304BA plate, it will be very difficult to peel off without deformation). Therefore, in consideration of such peeling workability and deformation of the stamper, the adhesive force at the time of peeling is usually particularly preferably within a range of 50 g / 25 mm or less in terms of adhesive force to a SUS-304BA plate. The lower the value, the better.

In order to sufficiently satisfy the demands of the pressure-sensitive adhesive film at the time of protection, peeling, and the like, the pressure-sensitive adhesive property is such that the pressure-sensitive adhesive strength to a SUS-304BA plate is Ag / 25 mm (10 ≦ A ≦ 2000), Bg / 25 mm (0 ≦ B ≦ 50, and B <
It is preferable to adjust the composition and thickness of the pressure-sensitive adhesive layer so as to satisfy A).

The method for producing the pressure-sensitive adhesive film of the present invention is as described above. However, from the viewpoint of preventing contamination of the signal irregularity surface of the stamper, a base film, a release film, a pressure-sensitive adhesive base material (a liquid containing a pressure-sensitive adhesive polymer). ), Etc., and the environment for preparing, storing, applying and drying the adhesive coating solution is Class 1,00 specified in US Federal Standard 209b.
It is preferable that the degree of cleanliness is maintained at 0 or less.
Further, the method for polishing the back surface of the stamper for an optical disk of the present invention comprises:
Similarly, from the viewpoint of contamination of the uneven surface for signal, class 1,000
It is preferable to carry out in an environment maintained at the following cleanliness.

[0059]

The present invention will be described below in further detail with reference to examples. The adhesive force and thickness variation of the pressure-sensitive adhesive films obtained in Examples and Comparative Examples, the thickness variation of the obtained stamper, and surface contamination were evaluated by the following methods.

(1) Measurement of adhesive strength (g / 25 mm) Except for the conditions specified below, all were JIS Z-0237.
Measure according to <Before ultraviolet irradiation>: At 23 ° C., the pressure-sensitive adhesive film obtained in the example or the comparative example was subjected to S
US304-BA plate (JIS G-4305 regulations, vertical:
(20 cm, width: 5 cm) and left for 1 hour. After standing, one end of the sample was clamped, and the peel angle: 180
Degree, peeling speed: 300 mm / min. SUS304-
The sample is peeled from the surface of the BA plate, and the stress at the time of peeling is measured and converted to g / 25 mm. <After UV irradiation>: At 23 ° C., the PSA films obtained in Examples and Comparative Examples were passed through the PSA layer to form SU.
S304-BA plate (JIS G-4305 regulation, vertical: 2
(0 cm, width: 5 cm) and left for 1 hour. After standing, the sample was irradiated with ultraviolet light from the substrate film side under the following conditions. After the irradiation, one end of the sample was sandwiched, and the peeling angle: 18
0 degree, peeling speed: 300 mm / min. With SUS304
-The sample is peeled from the surface of the BA plate, and the stress at the time of peeling is measured and converted to g / 25 mm. <Ultraviolet irradiation conditions> Source: High-pressure mercury lamp [manufactured by Oak Manufacturing Co., Ltd., type: OHD-320M] Illuminance: 30 mW / cm ² [Oak Manufacturing Co., Ltd., digital indicating type UV illuminometer UV-M02] (Receiver: UV
-35),] Irradiation time: 10 seconds Irradiation amount: 300 mJ / cm ²

(2) Measurement of variation in thickness of adhesive film (μm) 10c was obtained from the adhesive film obtained in the example or comparative example.
A sample of m square size is taken at random. With the release film peeled off, the thickness of the pressure-sensitive adhesive film (total of the base film and the pressure-sensitive adhesive layer) is measured at a total of 100 points every 1 cm in length and width, and the average value is determined. The difference between the maximum value or the minimum value and the average value is taken, and the larger value (a) of the absolute value is regarded as the thickness variation and is expressed by ± a (μm).

(3) Measurement of Variation in Thickness of Stamper after Backside Polishing (μm) The thickness of the portion of the stamper after the backside polishing, on which the signal irregularities were formed, obtained at the same time in Examples and Comparative Examples was measured. Measure 50 points at random and calculate the average value. The difference between the maximum value or the minimum value and the average value is calculated, and the larger absolute value (b)
Are thickness variations and are represented by ± b (μm).

(4) Observation of contamination on the signal irregularity forming surface of the stamper after back surface polishing The signal irregularity forming surface of the stamper after back surface polishing obtained in the example or the comparative example is observed with a microscope (× 800). And assess the status of contamination.

Example 1 A monomer mixture of 40 parts by weight of ethyl acrylate, 45 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of methyl acrylate and 5 parts by weight of glycidyl methacrylate was added to a benzoyl peroxide-based polymerization initiator [Nippon Oil & Fats Co., Ltd. (stock)
65 parts by weight of toluene using 0.8 parts by weight (0.32 parts by weight as an initiator) manufactured by Niiper BMT-K40
The reaction was carried out at 50 ° C. for 10 hours in 50 parts by weight of ethyl acetate. After completion of the reaction, the mixture was cooled, and 30 parts by weight of xylene was added thereto.
2.5 parts by weight of acrylic acid and tetradecyl dimethyl benzyl ammonium chloride [manufactured by NOF Corp., cationic M ₂ -100] 1.5 part by weight, reacted for 15 hours at 80 ° C. while blowing air, acrylic polymer (A main adhesive) was obtained.

To 100 parts by weight of the acrylic pressure-sensitive adhesive polymer, 5 parts by weight of benzyl dimethyl ketal [Nippon Ciba Geigy Co., Ltd., Irgacure 651] was added to 100 parts by weight of the acrylic pressure-sensitive adhesive polymer. A mixture of dipentaerythritol hexaacrylate and dipentaerythritol monohydroxypentaacrylate as a monomer having two or more polymerizable carbon-carbon double bonds [Aronix M-40, manufactured by Toa Gosei Chemical Industry Co., Ltd.
0], and an isocyanate-based crosslinking agent [Orester P4, manufactured by Mitsui Toatsu Chemicals, Inc.] as a thermal crosslinking agent.
9-60-SX] was added in an amount of 1.7 parts by weight (1 part by weight as a thermal crosslinking agent) to obtain an adhesive coating solution. This adhesive coating solution was directly applied to a polypropylene resin release film by a roll coater, dried at 120 ° C. for 1 minute,
A UV-curable pressure-sensitive adhesive layer having a thickness of 38 μm was formed on the surface of the obtained pressure-sensitive adhesive layer, and a corona discharge treatment was applied to the surface of the pressure-sensitive adhesive layer.
m of the polyethylene terephthalate film (base film, light transmittance at least at a part of the wavelength of 320 to 400 nm: 80% or more) was bonded and pressed to transfer the pressure-sensitive adhesive layer. After transfer, 2 hours at 60 ° C
After heating for 4 hours, the adhesive film for polishing the back surface of the stamper for an optical disk was manufactured by cooling to room temperature.

SUS-304B of the obtained adhesive film
Adhesive strength to A plate is 150g / 25m before UV irradiation
m, 8g / 25mm after UV irradiation, thickness variation ±
It was 2 μm. The release film is peeled off from the obtained adhesive film, and the thickness is about 0.3 m via the adhesive layer.
After sticking to the signal uneven surface of the stamper (before polishing) of the write-once optical disc (CD-R) of m, the back surface of the stamper was polished. After polishing the back surface, ultraviolet light from a source film side of the pressure-sensitive adhesive film using a high-pressure mercury lamp (manufactured by Oak Manufacturing Co., Ltd., type: OHD-320M) as an emission source: illuminance: 30 mW / cm ² , irradiation time: Irradiation was performed for 10 seconds under an irradiation amount of 300 mJ / cm ² , and the adhesive film was peeled off after the irradiation. The time required for attaching and detaching the pressure-sensitive adhesive film was a short time of about 1 minute in total, and did not require a special large-sized device. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Example 2 In the production of the pressure-sensitive adhesive film of Example 1, the thickness of the polyethylene terephthalate film (base film) was changed to 50.
μm (light transmittance at least at some wavelengths of 320 to 400 nm: 75% or more), and the thickness of the pressure-sensitive adhesive layer is 10 μm.
A pressure-sensitive adhesive film was produced in the same manner as in Example 1, except that The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 400 g / 25 mm before ultraviolet irradiation,
40g / 25mm after UV irradiation, thickness variation ± 3
μm. Using the obtained pressure-sensitive adhesive film, the back surface of a stamper (before polishing) for a reproduction-only compact disc (CD) having a thickness of about 0.3 μm was polished in the same manner as in Example 1. The time required for attaching and detaching the adhesive film was as short as about 1 minute in total, and no special large-sized device was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. In addition, when the signal uneven surface of the stamper was observed with a microscope (× 800), no contaminant was found. The results are shown in [Table 1].

Example 3 In the production of the pressure-sensitive adhesive film of Example 1, an isocyanate-based crosslinking agent [Mitsui Toatsu Chemical Co., Ltd., Olester P49]
-60-SX] was added at 8.5 parts by weight (5.1 parts by weight as a thermal crosslinking agent), the thickness of the polyethylene terephthalate film (base film) was 50 μm (the same as in Example 2), and the pressure-sensitive adhesive layer was used. Example 1 except that the thickness was 2 μm.
A pressure-sensitive adhesive film was produced in the same manner as described above. The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 15 g / 25 mm before ultraviolet irradiation, and 5 g / 2 after ultraviolet irradiation.
5 mm, and the thickness variation was ± 2 μm. Using the obtained pressure-sensitive adhesive film, the back surface of a stamper (before polishing) for a reproduction-only compact disc (CD) having a thickness of about 0.3 μm was polished in the same manner as in Example 1. The time required for attaching and detaching the adhesive film was as short as about 1 minute in total, and no special large-sized device was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. In addition, when the signal uneven surface of the stamper was observed with a microscope (× 800), no contaminant was found. The results are shown in [Table 1].

Example 4 In the production of the pressure-sensitive adhesive film of Example 1, an isocyanate crosslinking agent [Olester P-49, manufactured by Mitsui Toatsu Chemicals, Inc.]
-60SX] was added at 0.1 parts by weight (0.06 parts by weight as a thermal crosslinking agent), the thickness of the polyethylene terephthalate film (base film) was 50 μm (same as in Example 2), and the thickness of the pressure-sensitive adhesive layer was Was made in the same manner as in Example 1 except that the thickness was changed to 10 μm. The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 1800 g / 25 mm before ultraviolet irradiation, and 4 after ultraviolet irradiation.
5 g / 25 mm, and the thickness variation was ± 3 μm. Using the obtained adhesive film, in the same manner as in Example 1, a read-only compact disc (C
The back surface of the stamper D (before polishing) was polished. The total time required for attaching and detaching the adhesive film is 1
It took only a few minutes, and no special large-scale equipment was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Also,
Observation of the signal irregularity forming surface of the stamper with a microscope (× 800) revealed no contaminants. The results are shown in [Table 1].

Comparative Example 1 In a polymerization reactor, 150 parts by weight of deionized water and 4,4′-azobis-4-cyanovaleric acid (trade name: ACVA, manufactured by Otsuka Chemical Co., Ltd.) as a polymerization initiator were used in an amount of 0%. 0.5 parts by weight, 73.25 parts by weight of butyl acrylate, 14 parts by weight of methyl methacrylate, 9 parts by weight of 2-hydroxyethyl methacrylate, 2 parts by weight of methacrylic acid, 1 part by weight of acrylamide, and poly as a polymerizable surfactant Oxyethylene nonylphenyl ether (average of the number of moles of ethylene oxide added: about 20) in which a polymerizable 1-propenyl group is introduced into the benzene ring of an ammonium salt of a sulfate [Daiichi Kogyo Seiyaku Co., Ltd. Made: Aqualon HS
-20], emulsion polymerization was carried out at 70 ° C. for 9 hours with stirring using 0.75 parts by weight to obtain an acrylic resin-based water emulsion. This is neutralized with 14% by weight ammonia water,
An adhesive polymer emulsion having a solid content of about 40% by weight (adhesive base) was obtained. The obtained adhesive base emulsion 1
00 parts by weight (adhesive polymer concentration: about 40% by weight) was collected, and 14% by weight aqueous ammonia was added thereto to adjust the pH to 9.3.
Was adjusted. Next, 3 parts by weight of an aziridine-based cross-linking agent (manufactured by Nippon Shokubai Chemical Co., Ltd., Chemitite PZ-33) and 5 parts by weight of diethylene glycol monobutyl ether were added to obtain an adhesive coating solution. This pressure-sensitive adhesive coating solution was applied to a polypropylene film (release film, thickness: 50 μm) using a roll coater, and dried at 120 ° C. for 1 minute to provide a pressure-sensitive adhesive layer having a thickness of 10 μm. Next, the treated surface of a 50 μm-thick polyethylene terephthalate film (base film, the same as in Example 2) that had been subjected to corona discharge treatment was bonded and pressed to transfer the pressure-sensitive adhesive layer. After the transfer, the film was heated at 60 ° C. for 48 hours, and then cooled to room temperature to produce an adhesive film.

SUS-304B of the obtained adhesive film
160g / 25m before UV irradiation
m, 170 g / 25 mm after ultraviolet irradiation, and the thickness variation was ± 3 μm. Using the obtained adhesive film,
In the same manner as in Example 1, the back surface of a write-once compact disc (CD-R) stamper (before polishing) having a thickness of about 0.3 mm was polished. Although there was no particular problem in the workability of sticking the pressure-sensitive adhesive film, workability was poor for peeling without deforming the stamper, and the time required for sticking and peeling work was about 14 minutes in total. No special large equipment was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Also, the signal uneven surface of the stamper was changed to a microscope (8
(00 ×), no contaminants were found. The results are shown in [Table 1].

Comparative Example 2 In the production of the pressure-sensitive adhesive film of Example 1, the amount of the photopolymerization initiator added was 2 parts by weight, and dipentaerythritol hexamer was used as a monomer having two or more polymerizable carbon-carbon double bonds in the molecule. 0.2 parts by weight of a mixture of acrylate and dipentaerythritol monohydroxypentaacrylate (Aronix M-400, manufactured by Toa Gosei Chemical Industry Co., Ltd.), 10 μm thick adhesive layer, polyethylene terephthalate film (substrate Film) thickness of 5
An adhesive film was produced in the same manner as in Example 1 except that the thickness was set to 0 μm (the same as in Example 2). The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 400 g / 25 mm before ultraviolet irradiation, and 75 g / 25 after ultraviolet irradiation.
mm and thickness variation was ± 3 μm. Using the obtained pressure-sensitive adhesive film, a thickness of about 0.1 mm was obtained in the same manner as in Example 1.
The back surface of a 3 μm read-only compact disk (CD) stamper (before polishing) was polished. Although there was a particular problem in sticking the pressure-sensitive adhesive film, workability was poor for peeling without deforming the stamper, and the time required for sticking and peeling work was about 5 minutes in total. No special large equipment was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Also, the signal uneven surface of the stamper was changed to a microscope (8
(00 ×), no contaminants were found. The results are shown in [Table 1].

Comparative Example 3 In the production of the pressure-sensitive adhesive film of Comparative Example 1, the amount of butyl acrylate used was 66.25 parts by weight, the amount of methyl methacrylate used was 21 parts by weight, and an aziridine-based crosslinking agent [Nippon Shokubai Chemical Co., Ltd. Co., Ltd., Chemitite PZ-33] was added in an amount of 5 parts by weight, the thickness of the adhesive layer was 2 μm, and the thickness of the polyethylene terephthalate film (base film) was 50 μm.
An adhesive film was manufactured in the same manner as in Example 1 except that the same was used (as in Example 2). S of the obtained adhesive film
Adhesion to US-304BA plate is 8 before UV irradiation
g / 25 mm, 10 g / 25 mm after irradiation with ultraviolet rays, and thickness variation was ± 2 μm. Using the obtained pressure-sensitive adhesive film, the back surface of a stamper (before polishing) for a reproduction-only compact disc (CD) having a thickness of about 0.3 μm was polished in the same manner as in Example 1. The time required for sticking and peeling of the adhesive film may be as short as about 1 minute in total,
No special large equipment was required. When the polishing status of the obtained stamper was evaluated, no local dent was found, and the thickness variation of the stamper was ± 2 μm.
m and good. However, when the signal concavo-convex forming surface of the stamper was observed with a microscope (magnification: 800), some contamination due to intrusion of abrasive or the like was observed around the stamper. The results are shown in [Table 1].

Comparative Example 4 In the production of the pressure-sensitive adhesive film of Example 1, the thickness of the pressure-sensitive adhesive layer was 13 μm, and the thickness of the polyethylene terephthalate film (base film) was 90 μm (320 nm).
Light transmittance at at least some wavelengths of ４００400 nm:
An adhesive film was produced in the same manner as in Example 1 except that the dispersion in thickness of the adhesive layer and the polyethylene terephthalate film (base film) was increased. SUS-304B of the obtained adhesive film
Adhesive strength to A plate is 450g / 25m before UV irradiation
m, after irradiation with ultraviolet light, 40 g / 25 mm, and the thickness variation was ± 7 μm. Using the obtained pressure-sensitive adhesive film, the back surface of a stamper (before polishing) for a reproduction-only compact disc (CD) having a thickness of about 0.3 μm was polished in the same manner as in Example 1. The time required for sticking and peeling of the adhesive film was a short time of about 1 minute in total. Also,
No special large equipment was required. When the polishing conditions of the obtained stamper were evaluated, there was no local dent, but the thickness variation of the stamper was ± 6 μm, which was a level that would cause problems when used for injection (compression) molding. . Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Comparative Example 5 A commercially available liquid for a polymer protective film [trade name: Clean Coat S, manufactured by Fine Chemical Japan Co., Ltd.]
A 3 mm write-once type compact disc (CD-R) stamper (before polishing) is spin-coated on the signal uneven surface so as to have a thickness of about 30 μm after drying and dried for about 1 hour. Was polished. On this occasion,
A local evacuation facility for solvent evacuation and a large-scale spin coater with strictly controlled cleanliness were required. After the polishing, the protective film was peeled off and removed. However, at the time of peeling, a part of the protective film remained on the signal irregularity forming surface, so that it was necessary to perform solvent cleaning. It took about one hour to wash the solvent. When the polishing status of the obtained stamper was evaluated, no local dent was found, and the thickness variation of the stamper was as good as ± 2 μm or less. In addition, when the signal irregularity-formed surface of the stamper was observed with a microscope (magnification: 800), several foreign substances having a size of about 3 μm were found, and further cleaning was required. The results obtained are shown in [Table 1].

[0076]

[Table 1]

[0077]

The pressure-sensitive adhesive film of the present invention comprises a UV-transparent substrate film and a UV-curable pressure-sensitive adhesive layer formed on one surface of the film, and the pressure-sensitive adhesive properties before and after the UV curing fall within a specific range. Because it is limited, when it is used to polish the back surface of the stamper, it is adhered with sufficient adhesive strength to protect the signal uneven surface, and when it is peeled off, it is irradiated with ultraviolet light in a specific range. Since the adhesive strength is reduced to a certain extent, the peeling is extremely easy, the peeling can be performed in a short time, and the stamper is not deformed by the peeling stress. Further, since the pressure-sensitive adhesive is cured by ultraviolet irradiation before peeling, no contamination due to the pressure-sensitive adhesive remains on the signal uneven surface after peeling. Furthermore, if the adhesive film of the present invention is used,
There is no need to form a protective layer by spin-coating a solution of a polymer on the signal uneven surface of the stamper. Therefore, a solution application, a drying operation, and the like for forming the protective layer can be omitted, and the operation time can be greatly reduced. Since there is no generation of organic solvent gas when drying the applied polymer solution, there is no risk of polluting the environment. Therefore, by using the pressure-sensitive adhesive film of the present invention, it is possible to improve the workability at the time of polishing the back surface of the stamper for an optical disc, prevent environmental pollution, and the like.

Claims (6)

[Claims] 1. A back surface of a stamper for an optical disk, wherein an adhesive film is directly attached to a surface of the stamper for an optical disk on which pits and protrusions and / or grooves are formed, and the back surface of the stamper is polished. In a polishing method, the pressure-sensitive adhesive film is composed of a UV-permeable base film and a UV-curable pressure-sensitive adhesive layer formed on one surface of the film, and has an average thickness of 20 to 300 μm and a thickness variation of ± 10% of the average thickness. 5 μm or less and SUS3
The adhesion to the 04-BA plate is 1 before UV irradiation (A)
0-2000 g / 25 mm, 0 (B) after UV irradiation
50 g / 25 mm (where A> B), and the adhesive film is irradiated with ultraviolet rays of 50 to 3000 mJ / cm ² after the polishing of the back surface of the stamper and before the adhesive film is peeled off. Backside polishing method. 2. The method according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 15 μm. 3. The method for polishing the back surface of an optical disk stamper according to claim 1, wherein the thickness variation of the adhesive film is within ± 3 μm of the average thickness. 4. An adhesive film for polishing the back surface of a stamper for an optical disk, which is directly attached to the surface of the stamper for forming an unevenness for pits and / or grooves when the back surface of the stamper for an optical disk is polished. Is composed of an ultraviolet-permeable base film and an ultraviolet-curable pressure-sensitive adhesive layer formed on one surface thereof, and has an average thickness of 20 to 30.
0 μm, the thickness variation is within ± 5 μm of the average thickness, and the adhesive strength to the SUS304-BA plate is 10 to 2000 g / 25 mm, 50 μm before ultraviolet irradiation (A).
After irradiating with ultraviolet rays of 3000 mJ / cm ² (B),
An adhesive film for polishing the back surface of a stamper for an optical disk, wherein 0 g / 25 mm (where A> B). 5. The pressure-sensitive adhesive film for polishing the back surface of a stamper for an optical disk according to claim 4, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 15 μm. 6. The pressure-sensitive adhesive film for polishing the back surface of a stamper for an optical disk according to claim 4, wherein the thickness variation is within ± 3 μm of the average thickness.