JP2005271236A - Long roll-like functional film, its manufacturing method and optical data recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long roll-like functional film which has a functional layer such as a hard coat layer or the like and to which a suface protective film easy to peel and having a proper tack with respect to a base material is bonded. <P>SOLUTION: The long roll-like functional film is formed by providing the functional layer on one side of a transparent plastic film base material and bonding a surface protective film to the other surface thereof and characterized in that the tack of the surface protective film with the transparent plastic film base material is 100-500 mN/25 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a long roll-like functional film protected by a surface protective film and a method for producing the same. Specifically, a long roll-shaped functional film with a surface protective film, especially a polycarbonate film, which solves the problems of complexity and resource saving in the manufacturing process, using a long roll-shaped plastic film protected by a surface protective film. The present invention relates to a hard coat film as a substrate and a method for producing the same.
The present invention also relates to an optical information recording medium provided with this hard coat film.

In recent years, under the circumstances where networks such as the Internet and high-definition TVs are rapidly spreading, various light sources such as a CD-R and a DVD-R are used as large-capacity recording media capable of recording image information inexpensively and easily. Information recording media (optical disks) have been proposed. Recently, a DVR system that records and reproduces with a blue-violet laser has been announced (see, for example, Non-Patent Document 1), and an optical disk with a high recording density and a large capacity (single-side recording capacity of approximately 22.5 gigabytes) has been realized.
In such an optical information recording medium for a blue-violet laser light source, a recording layer formed on a substrate is covered with a thin cover layer having a thickness of 0.1 mm to 0.3 mm. The cover layer is for protecting the recording layer, and is generally composed of a light-transmitting base film and an adhesive layer provided on one surface thereof.
As the light transmissive substrate film, a polycarbonate film is generally used as one having a thermal expansion coefficient approximate to that of an optical disk substrate (usually polycarbonate resin). In addition, in order to improve the concentration of the laser beam, this light-transmitting substrate film is selected so that the surface is as flat as possible and birefringence is not easily generated, and the optical head of the drive is placed on the film surface. A scratch-preventing layer such as a hard coat layer is provided on the surface of the base film opposite to the pressure-sensitive adhesive layer so that it is difficult to be scratched even when contacted.

  Generally, as a method for forming a hard coat layer on a plastic film substrate, an ultraviolet curable composition is applied on the substrate and dried, and then the composition is hardened by ultraviolet irradiation. A method in which the step of forming a layer is continuously performed roll-to-roll, that is, in the form of a long roll film is highly productive and widely used.

By the way, the above-described polycarbonate film for optical use such as that used for the cover layer of an optical disk has a flat surface, so that it cannot be wound into a roll as it is to form a wound layer. This is because it is difficult to form unevenness on the surface and maintain slipperiness while maintaining high light transmittance. Therefore, in order to obtain a long roll-shaped plastic film for optical use, a so-called surface protective film is bonded to a polycarbonate film.
As this surface protective film, a film produced by coextrusion of polyethylene and an adhesive layer made of an ethylene / vinyl acetate copolymer is generally used. The surface of the adhesive layer has weak adhesion to the polycarbonate film surface. Immediately before winding up the polycarbonate film, a surface protective film is applied, niped gently, and then wound up with a winder to obtain a film wound layer body. be able to.
Using the long roll-like polycarbonate film with the surface protective film thus obtained as a base material, the hard coat layer is formed after the surface protective film is peeled off or while the surface protective film is bonded. A long roll-shaped hard coat film can be produced.

In Patent Document 1, a long polycarbonate film having a surface opposite to the surface on which a hard coat layer is to be formed is protected by a surface protective film, the length direction of the film from a feeder via a guide roll. The hard coat material is applied to the surface on which the hard coat layer is to be formed and dried to form a hard coat material application layer, and the obtained polycarbonate film is passed through the guide roll in the length direction of the film. A method of conveying and winding is disclosed.
JP 2002-121306 A Optical Memory International Symposium (ISOM2000) Proceedings, p.210-211

When a hard coat film is used for optical applications, the surface of the hard coat layer is required to be smooth. Similarly to the case of winding a polycarbonate film having a smooth surface, a film provided with a hard coat layer can also be used. It is difficult to wind up without a surface protection film. Therefore, regardless of the presence or absence of the surface protective film when forming the hard coat layer, a surface protective film is required when winding up the completed hard coat film. In this case, the hard coat layer is formed with the surface protective film bonded. This is very preferable in terms of suppressing an increase in the number of processes and an increase in required resources accompanying the removal of the surface protective film.
However, the adhesive strength between the surface protective film and the polycarbonate film is increased by heating in the drying process to form the hard coat layer, and the finished long roll hard coat film has a surface protective film. Becomes difficult to peel off, and a new problem arises in that the film is scratched or broken during peeling.
Patent Document 1 discloses a method for forming a hard coat layer while a surface protective film is bonded, but is intended to prevent damage to the polycarbonate film during transportation or formation of the hard coat layer. There is no mention of a problem related to an increase in the adhesion between the surface protective film and the polycarbonate film or a solution to the problem.

In view of such a situation, the present invention has a functional layer such as a hard coat layer, and is a long roll-like function in which a surface protective film that is easily peelable and has an appropriate adhesive force is bonded. It is an object to provide a sex film and a method for producing the same. In particular, an object of the present invention is to provide a long roll-shaped functional film, particularly a hard coat film, and a method for producing the same, which uses a polycarbonate film and solves the problems of complexity of the production process and resource saving.
Another object of the present invention is to provide an optical information recording medium provided with a hard coat film obtained from the long roll-like hard coat film.

  As a result of intensive studies, the present inventors have solved the above problem by controlling the adhesive force between the surface protective film and the base material in the long roll functional film bonded with the surface protective film after winding. The inventors have found that the problem can be solved and have completed the present invention.

Specifically, the above problem is solved by the following means.
1. It has a functional layer on one side of the transparent plastic film base, and a surface protective film is bonded to the other side. The adhesive force between the surface protective film and the transparent plastic film base is 100 to 500 mN / 25 mm. A long roll-like functional film characterized by being

2. 2. The long roll-like functional film as described in 1 above, wherein the surface roughness Ra of the transparent plastic film substrate is 5 nm or less.
3. 3. The long roll-like functional film as described in 1 or 2 above, wherein the transparent plastic film substrate has an in-plane retardation (birefringence) value Re of 10 nm or less.
4). 4. The long roll-like functional film as described in any one of 1 to 3 above, wherein the transparent plastic film substrate is a polycarbonate film produced by a casting method (solvent casting method).
5). 5. The long roll-shaped functional film as described in any one of 1 to 4 above, wherein the transparent plastic film substrate has a thickness of 70 to 120 μm.
6). 6. The long roll-like functional film as described in 5 above, wherein the transparent plastic film substrate has a thickness of 70 to 90 μm.

7). The surface protective film and the transparent plastic film base material are bonded via an adhesive layer,
50-90 mass% of ethylene-α-olefin copolymer having a density of 0.898-0.920 g / cm ³ polymerized using a single-site catalyst, and a density polymerized using a Ziegler catalyst The long roll-like functional film as described in any one of 1 to 6 above, comprising a mixture of 0.918 to 0.925 g / cm ³ of low density polyethylene as a main component.

8). The surface protective film and the transparent plastic film base material are bonded via the adhesive layer.
Any one of 1 to 6 above, wherein the pressure-sensitive adhesive layer has, as a main component, an ethylene-α-olefin copolymer having a density of 0.898 to 0.920 g / cm ³ polymerized using a single site catalyst. The long roll-like functional film according to crab.

  9. The long roll shape according to any one of 1 to 6 above, wherein the surface protective film is a surface protective film with an adhesive layer produced by coextruding polyethylene and an ethylene / vinyl acetate copolymer. Functional film.

10. 10. The long roll-shaped hard coat film as described in any one of 1 to 9 above, wherein the functional layer is a hard coat layer.
11. The hard coat layer has scratch resistance such that when the surface is rubbed 50 times with a steel wool of # 0000 under a load of 1.96 N / cm ² , the rubbing marks are not visible visually. The long roll-shaped hard coat film described in 1.
12 The long roll-shaped hard coat film as described in 10 or 11 above, which is used as a cover layer of an optical information recording medium which is read and written by blue laser light having a wavelength of 400 to 432 nm.

13. It is a manufacturing method of the long roll-like functional film in any one of said 1-12,
A transparent plastic film in the form of a long roll with a surface protective film bonded is transported in the length direction from the feeder via a guide roll, and the side opposite to the surface of the transparent plastic film with the surface protective film bonded On the surface, a curable composition is applied, dried and cured to form a functional layer, and the method includes a step of winding the surface protective film while the surface protective film is being bonded. Method.
14 14. The method for producing a long roll-shaped functional film as described in 13 above, wherein the drying temperature when forming the functional layer is 65 ° C. or lower.
15. 15. The method for producing a long roll-shaped functional film as described in 14 above, wherein the drying temperature when forming the functional layer is 55 ° C. or lower.
16. 16. The method for producing a long roll-shaped functional film as described in 14 or 15 above, wherein the drying time when forming the functional layer is 2 minutes or less.
17. The long roll-like functionality according to any one of 13 to 16 above, wherein the curable composition contains an organic solvent, and the organic solvent having a boiling point of 130 ° C. or lower is 90% by mass or more in the total solvent. Film.
18. 18. The long roll-like functional film as described in 17 above, wherein the curable composition contains an organic solvent, and the organic solvent having a boiling point of 90 ° C. or lower is 40% by mass or more in the total solvent.
19. 19. The long roll-like functional film as described in any one of 13 to 18 above, wherein the curable composition is an active energy ray curable composition.

  20. 13. An optical information recording medium comprising a hard coat film obtained from the long roll-shaped hard coat film described in 12 as a cover layer.

According to the present invention, a long roll functional film with a surface protective film having a functional layer such as a hard coat layer, the long roll functional film having an appropriate adhesive force between the surface protective film and the substrate. Can be provided. In the long roll-like functional film of the present invention, the surface protective film is not peeled off by itself, but can be easily peeled off when attempting to peel off.
According to the present invention, when a long roll-shaped polycarbonate film protected by a surface protective film is used to produce a long roll-shaped functional film, in particular, a long roll-shaped hard coat film, the manufacturing process is simplified. And resource saving.
Moreover, the optical information recording medium provided with the polycarbonate film with a hard coat can be provided.

Hereinafter, the long roll-shaped functional film protected by the surface protective film of the present invention and a method for producing the same will be described.
In the present specification, the description “(numerical value 1) to (numerical value 2)” representing a physical property value or a characteristic value means “(numerical value 1) or more and (numerical value 2) or less”.

The long roll-like functional film of the present invention has a functional layer on one surface of a transparent plastic film base material, and a surface protective film is bonded to the other surface. The surface protective film and the transparent plastic film are The adhesive strength with the substrate is 100 to 500 mN / 25 mm.
Thus, in the long roll-like functional film of the present invention, the surface protective film and the transparent plastic film base material have an appropriate adhesive force, so the surface protective film will not be peeled by itself, Can be easily removed.
The adhesive force between the surface protective film and the transparent plastic film substrate is preferably 150 to 400 mN / 25 mm, more preferably 180 to 300 mN / 25 mm.

  The long roll functional film of the present invention in which the surface protective film and the transparent plastic film base material have appropriate adhesive strength as described above is a long roll-shaped transparent plastic film to which the surface protective film is bonded. It is transported in the length direction from the unwinding machine via a guide roll, and functions by applying, drying, and curing the curable composition on the surface opposite to the surface where the surface protective film of the transparent plastic film is bonded. It can produce by the manufacturing method including the process which forms a property layer and winds up, bonding a surface protection film. That is, it can be produced by forming a functional layer on a long roll-shaped transparent plastic film base material on which a surface protective film is bonded, with the surface protective film being bonded, and winding it further. In this production method of the present invention, the functional layer can be formed while the surface protective film is bonded, so that the production process is simplified and the amount of the surface protective film used can be reduced.

  In the production method of the present invention, the adhesive force between the surface protective film and the transparent plastic film substrate in the stage before forming the functional layer is preferably 100 to 500 N / 25 mm. By setting it within this range, the entire transparent plastic film with a surface protective film can be sent out from the unwinder, applied with a curable composition, and can be handled without removing the surface protective film in the process leading to drying. At the same time, the surface protective film can be easily peeled off in the long roll functional film with the surface protective film after the functional layer is formed and wound. The adhesive force between the surface protective film and the transparent plastic film substrate in the previous stage of forming the functional layer is preferably 120 to 350 mN / 25 mm, more preferably 150 to 250 mN / 25 mm.

Moreover, in the manufacturing method of this invention, it is preferable that the drying temperature when forming a functional layer shall be 65 degrees C or less.
Conventionally, a surface protective film with an adhesive layer obtained by co-extrusion of an adhesive layer made of polyethylene and an ethylene / vinyl acetate copolymer has been used for such applications. In the process of forming the functional layer, the pressure-sensitive adhesive layer as used herein is increased in its adhesive strength due to heat in the drying process, and it becomes difficult to peel off the surface protective film from the functional film after completion. When it was forcibly removed, the functional film was damaged in the process of peeling.
In this invention, the increase in the adhesive force of an adhesive layer can be suppressed because the drying temperature at the time of forming a functional layer shall be 65 degrees C or less. The drying temperature when forming the functional layer is more preferably 55 ° C. or lower. The drying time is preferably 2 minutes or less, more preferably 1 minute or less. The shorter the time of exposure to high temperatures, the more the increase in adhesive strength can be suppressed. Even when the drying temperature is 65 ° C. or less, if the drying time is as long as 3 minutes or more, the adhesive strength may exceed 500 mN / 25 mm, and the surface protective film may be difficult to peel off.

Furthermore, in the production method of the present invention, it is preferable to include a low boiling point solvent in the curable composition for forming the functional layer. Specifically, it is preferable to contain an organic solvent having a boiling point of 130 ° C. or lower in the total solvent of 90% by mass or more, and more preferable to include an organic solvent having a boiling point of 90 ° C. or lower in the total solvent of 40% by mass or more.
Thus, by using a low boiling point solvent as a diluent for the curable composition, the solvent can be sufficiently skipped during drying, and the functional layer can be cured well.
It is also effective to use a low viscosity curable composition containing no organic solvent as a diluent.

In addition, when the functional layer is cured by ultraviolet irradiation in the present invention, heat generated at the time of curing and heat generated from the ultraviolet irradiation lamp may be transmitted to the pressure-sensitive adhesive layer, thereby increasing the adhesive strength. In order to prevent this, it is preferable to perform ultraviolet irradiation while cooling the film. The film is preferably cooled using a rotating drum that conveys the film in contact with the surface protective film side. It is preferable to cool the drum by passing cooling water through the rotating drum and to irradiate ultraviolet rays while cooling from the surface protective film side by the cooling rotating drum.
Moreover, it is preferable to perform ultraviolet irradiation, reducing oxygen concentration. The preferred oxygen concentration is 1% or less, more preferably 0.5% or less, and particularly preferably 0.3% or less. When the oxygen concentration exceeds 1%, sufficient scratch resistance may not be obtained due to inhibition of curing by oxygen. Even if the oxygen concentration is 1% or less, the lower the oxygen concentration, the better. Strictly speaking, even when the oxygen concentration is 1% or less, curing inhibition by oxygen occurs. This inhibition of curing can be compensated by increasing the amount of ultraviolet irradiation, but it is preferable that the oxygen concentration is lower from the viewpoint of reducing the amount of heat generated from the ultraviolet irradiation lamp and suppressing the increase in adhesive force.

[Adhesive layer]
In the long roll-like functional film of the present invention, the surface protective film and the transparent plastic film substrate can be bonded via an adhesive layer.
As the pressure-sensitive adhesive layer, even when heated to a high temperature in the drying step when forming with the functional layer, the increase in the adhesive force is slight, the subsequent surface protective film can be easily peeled off, and the initial at room temperature An adhesive layer having sufficient adhesive strength is preferred.

As such an adhesive layer, an ethylene-α-olefin copolymer having a density of 0.898 to 0.920 g / cm ³ polymerized using a single site catalyst, and a Ziegler catalyst are used. Examples thereof include a pressure-sensitive adhesive layer having as a main component a mixture of 10 to 50% by mass of low density polyethylene having a density of 0.918 to 0.925 g / cm ³ . Here, a main component means the component which brings about the adhesive force which an adhesive layer has.

The ethylene-α-olefin copolymer used here uses a single site catalyst as a polymerization catalyst, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, etc. as a comonomer (α-olefin) Among the copolymerized polyethylene (so-called linear low-density polyethylene or metallocene polymer) obtained using the above, the density is 0.898 to 0.920 g / cm ³ . It is preferable that the single peak of the melting curve obtained by differential scanning calorimetry is 80 to 100 ° C. A single peak of this melting curve is obtained by SSC5100 manufactured by Seiko Denshi Kogyo Co., Ltd., heated to 200 ° C. at a heating rate of 10 ° C./min, cooled to room temperature, and again 200 ° C. at a heating rate of 10 ° C./min. It can be determined from the measured value when the temperature is raised to.
A large number of such ethylene-α-olefin copolymers are commercially available, and typical examples thereof include Evole manufactured by Mitsui Chemicals, Kernel manufactured by Nippon Polychem, and the like.

Increased adhesive strength at high temperature heating by using low density polyethylene with a density of 0.918 to 0.925 g / cm ³ polymerized using a Ziegler catalyst to the ethylene-α-olefin copolymer. Can be suppressed very well.
The ethylene-α-olefin copolymer has a narrow molecular weight distribution and few crystal parts. For this reason, when the pressure-sensitive adhesive layer is formed using this resin, a pressure-sensitive adhesive layer having good smoothness and excellent room temperature adhesion to a transparent plastic film substrate (particularly polycarbonate film) can be obtained. However, it is superior to the pressure-sensitive adhesive layer made of an ethylene / vinyl acetate copolymer in terms of the temperature stability of the pressure-sensitive adhesive force. However, the pressure-sensitive adhesive force increases so that it becomes difficult to peel off when exposed to a high temperature. The low density polyethylene further improves the temperature stability of the adhesive strength of such an ethylene-α-olefin copolymer.

It is important that the density of the ethylene-α-olefin copolymer to be mixed and the density of the low-density polyethylene are in the above range, and an ethylene-α-olefin copolymer having a density of less than 0.898 g / cm ³ is obtained. If used, the cohesive force of the pressure-sensitive adhesive layer is insufficient, and when peeled off, a part of the pressure-sensitive adhesive remains on the adherend and contaminates the surface. On the other hand, when an ethylene-α-olefin copolymer having a density exceeding 0.920 g / cm ³ is used, it is difficult to obtain a pressure-sensitive adhesive layer having a necessary initial adhesive force.
Moreover, in the low density polyethylene whose density is less than 0.918 g / cm < ³ >, the effect | action which suppresses the adhesive force raise when an ethylene-alpha-olefin copolymer is heated is weak, and sufficient combination effect cannot be expected. Low density polyethylene having a density exceeding 0.925 g / cm ³ has poor compatibility with the ethylene-α-olefin copolymer, and causes various inconveniences such as insufficient initial adhesive strength, poor workability, and poor transparency.

  Preferred mixture composition to minimize the increase in adhesive strength at high temperatures while ensuring the necessary initial adhesive strength using ethylene-α-olefin copolymer and low density polyethylene in a specific density range as described above These are 50-90 mass% of ethylene-alpha-olefin copolymers and 10-50 mass% of low density polyethylene. If the amount of the ethylene-α-olefin copolymer is too much, the blending effect of the low density polyethylene is not sufficient. On the other hand, if the amount of the low density polyethylene is too large, the necessary initial adhesive force can be achieved. Can not. In particular, a preferable mixing ratio is 60 to 80% by mass of an ethylene-α-olefin copolymer and 20 to 40% by mass of low density polyethylene.

  If necessary, a small amount (preferably 5% by mass or less) of a tackifier can be added to the mixture of the ethylene-α-olefin copolymer and the low density polyethylene to increase the initial adhesive force. As the tackifier to be blended, it is preferable that the mixture of the ethylene-α-olefin copolymer and the low-density polyethylene has a good compatibility and gives a transparent mixture. Examples include terbene resins, terbene resins, and terbene phenol resins.

  In addition to the above, the pressure-sensitive adhesive layer that can be used in the long roll-like functional film of the present invention includes a pressure-sensitive adhesive layer containing the ethylene-α-olefin copolymer as a main component, and ethylene / vinyl acetate copolymer. A pressure-sensitive adhesive layer containing a polymer as a main component can be mentioned. Here, a main component means the component which brings about the adhesive force which an adhesive layer has. When using these pressure-sensitive adhesive layers, as described above, by adjusting the drying temperature and the like when forming the functional layer, it is possible to suppress an increase in pressure-sensitive adhesive force, can do.

[Surface protection film]
As the surface protective film of the long roll-like functional film of the present invention, a polyethylene film is preferable. As the polyethylene film, a high-density polyethylene film or a low-density polyethylene film having a thickness of 20 to 100 μm (preferably 30 to 80 μm), which is usually used for this kind of application, can be used.

  The surface protective film used in the present invention is formed by, for example, coextruding polyethylene and an ethylene / vinyl acetate copolymer, and forming polyethylene and a resin for forming an adhesive layer into a laminated film by a coextrusion method. It can be easily manufactured by laminating at the same time as the formation of the layered surface protective film. However, the production method is not limited to the coextrusion method.

  In the present invention, the thickness of the surface protective film and the pressure-sensitive adhesive layer is not particularly limited. Usually, a surface protective film having a thickness of 10 to 20 μm is applied to a surface protective film having a thickness of 30 to 80 μm. preferable.

  The method for bonding the surface protective film of the present invention to the transparent plastic film substrate is not particularly different from that of the conventional surface protective film. That is, the pressure-sensitive adhesive layer side of the surface protective film is pressed against the surface of the transparent plastic film base material. Good adhesion is possible at temperatures from room temperature to about 80 ° C.

[Transparent plastic film substrate]
Examples of the transparent plastic film substrate used in the present invention include polyesters such as polyethylene terephthalate and polyethylene naphthalate, cellulose acylates such as cellulose triacetate, cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate, polycarbonate, and polymethyl Films such as methacrylate, polycarbonate, polysulfone, polyethersulfone, polyarylate, and cycloolefin polymer are preferred.
The thickness of the transparent plastic film substrate is preferably 20 to 300 μm, more preferably 50 to 200 μm, and particularly preferably 70 to 120 μm. This range is preferable because it is easy to ensure appropriate film strength and rigidity.

When the functional film obtained from the long roll-shaped functional film of the present invention is used as a cover layer of an optical disk, the transparent plastic film substrate is preferably polycarbonate, cellulose acetate, or an acrylic polymer. Also, the optical film base to which the functional film is applied is preferably similar to the thermal expansion coefficient, and since polycarbonate resin is generally used as the resin substrate of the optical disk, polycarbonate is also used in this functional film. A film is preferred.
Moreover, it is preferable that the moisture absorption rate in 23 degreeC50% RH of a transparent plastic film base material is 5% or less.

Furthermore, the surface roughness Ra of the transparent plastic substrate film as the cover layer is preferably 5 nm or less, and more preferably 3 nm or less. The smaller the surface roughness Ra, the smoother the surface, which is preferable for condensing the laser beam on the recording layer of the optical disc. Furthermore, the in-plane retardation (birefringence) value Re is preferably 10 nm or less, and more preferably 8 nm or less. The smaller the birefringence, the smaller the optical anisotropy, which is preferable for condensing the laser beam on the recording layer of the optical disk.
In the present invention, the term “transparent” means that when used in an optical disc, the laser beam that is recorded / reproduced is transmitted (transmittance: preferably 80% or more, more preferably 86% or more). Means transparent.

[Polycarbonate film]
As a transparent plastic film base material, the thickness of the polycarbonate film is preferably 20 to 300 μm, more preferably 50 to 200 μm, and particularly preferably 70 to 120 μm. Furthermore, when the functional film obtained from the long roll-like functional film of the present invention is used as a cover layer of an optical disk, the thickness of the polycarbonate film is most preferably 70 to 90 μm.
The film forming method of the polycarbonate film may be a melting method or a casting method (solvent casting method). However, since the casting method easily forms a film having low optical anisotropy, an optical film is used. In particular, it is preferable from the viewpoint of producing a base material for an optical disc cover layer.

[Functional layer]
The functional layer of the present invention may be formed of either a thermosetting composition or an active energy ray curable composition, but may be formed of an active energy ray curable composition from the viewpoint of productivity. Preferably, it is particularly preferably formed by an ultraviolet curable composition.
The film thickness of the functional layer is preferably 10 μm or less, particularly when the transparent plastic film substrate is a polycarbonate film. Polycarbonate film is soft (low rigidity), and if the cured film thickness of the functional layer exceeds 10 μm, curling may occur.

[Hard coat layer]
A hard coat layer is mentioned as a functional layer of this invention. In this case, the hard coat layer is a hardened layer having a scratch resistance in which, when the surface is rubbed 50 times using a steel wool of # 0000 and applying a load of 1.96 N / cm ² , the scratch marks are not visible. It is preferable that
Further, when the transparent plastic film substrate is a polycarbonate film, the rigidity is low. Therefore, if the cured film is too thick, curling is likely to occur, and if it is too thin, the hard coat function is difficult to develop. ˜10.0 μm is preferable, 2.0 to 6.0 μm is more preferable, and 2.5 to 5.0 μm is particularly preferable.

A preferred method for forming the hard coat layer of the present invention is a method in which an ultraviolet curable composition that is cured by ultraviolet irradiation is applied on a transparent plastic film substrate, dried, and then the composition is cured by ultraviolet irradiation. .
In the ultraviolet curable composition, a compound containing two or more ethylenically unsaturated groups in the same molecule which is polymerized or cross-linked by ultraviolet irradiation and cured is preferably used. Hereinafter, an ultraviolet curable composition having a compound containing two or more ethylenically unsaturated groups in the same molecule that can be preferably used in the present invention and preferably used in the present invention will be described.

  The ethylenically unsaturated group is preferably an acryloyl group, a methacryloyl group, a styryl group, or a vinyl ether group, and particularly preferably an acryloyl group. Although the compound containing an ethylenically unsaturated group should just have two or more ethylenically unsaturated groups in a molecule | numerator, More preferably, it is three or more. Among them, a compound having an acryloyl group is preferable, and a compound called a polyfunctional acrylate monomer having 2 to 6 acrylate groups in the molecule or a molecule called urethane acrylate, polyester acrylate or epoxy acrylate. An oligomer having several acrylate groups and a molecular weight of several hundred to several thousand can be preferably used.

Preferred examples of the compound having two or more ethylenically unsaturated groups in the molecule include divinylbenzene, ethylene glycol diacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, and pentaerythritol. Polyol polyacrylates such as tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, diacrylate of bisphenol A diglycidyl ether, epoxy acrylates such as diacrylate of hexanediol diglycidyl ether, polyisocyanate and hydroxy Urethane acrylate obtained by reaction of hydroxyl-containing acrylate such as ethyl acrylate It can gel.
Moreover, such a compound is also marketed, and EB-600, EB-40, EB-140, EB-1150, EB-1290K, IRR214, EB-2220, TMPTA, TMPTMA (above, Daicel UCB ( Co., Ltd.), UV-6300, UV-1700B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and the like.
Among the compounds having 2 or more ethylenically unsaturated groups in the molecule mentioned above, particularly preferred compounds include compounds having 3 or more acryloyl groups in the molecule and an acryloyl equivalent of 120 or less. Examples include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

In addition to the compound having two or more ethylenically unsaturated groups in the molecule, examples of the compound preferably used in the ultraviolet curable composition of the present invention include a curable resin containing a ring-opening polymerizable group.
The curable resin containing a ring-opening polymerizable group is a curable resin having a ring structure in which ring-opening polymerization proceeds by the action of a cation, an anion, or a radical, and among them, a heterocyclic group-containing curable resin is preferable. Examples of such curable resins include epoxy group-containing compounds, oxetanyl group-containing compounds, tetrahydrofuranyl group-containing compounds, cyclic lactone compounds, cyclic carbonate compounds, oxazolinyl group-containing compounds and the like, especially epoxy group-containing compounds. Compounds, oxetanyl group-containing compounds, and oxazolinyl group-containing compounds are preferred. In the present invention, the curable resin having a ring-opening polymerizable group preferably has two or more ring-opening polymerizable groups in the same molecule, more preferably three or more. In the present invention, two or more curable resins having a ring-opening polymerizable group may be used in combination. In this case, a curable resin having one ring-opening polymerizable group in the same molecule is used as necessary. Can be used together.

  The curable resin having a ring-opening polymerizable group used in the present invention is not particularly limited as long as it is a curable resin having a cyclic structure as described above. Preferred examples of such curable resins include monofunctional glycidyl ethers, monofunctional alicyclic epoxies, difunctional alicyclic epoxies, diglycidyl ethers (for example, ethylene glycol diglycidyl ether as glycidyl ethers). , Bisphenol A diglycidyl ether, trimethylol ethane triglycidyl ether), trifunctional or higher glycidyl ethers (trimethylol ethane triglycidyl ether, trimethylol propane triglycidyl ether, glycerol triglycidyl ether, triglycidyl trishydroxyethyl isocyanurate, etc. ) Tetrafunctional or higher functional glycidyl ethers (sorbitol tetraglycidyl ether, pentaerythritol tetraglycyl ether, cresol novolac resin) An acrylic polymer having an epoxy group in the side chain, such as polyglycidyl ether of a polyglycidyl ether, a polyglycidyl ether of a phenol novolac resin, a polyglycidyl methacrylate, an alicyclic epoxy (Celoxide 2021P, Celoxide 2081, Epolide GT-301, EPOLIDE GT-401 (manufactured by Daicel Chemical Industries, Ltd.), EHPE (manufactured by Daicel Chemical Industries, Ltd.), phenol novolac resin polycyclohexyl epoxy methyl ether, etc., oxetanes (OX-SQ, PNOX-1009) (The above-mentioned, Toagosei Co., Ltd.) etc. are mentioned, but this invention is not limited to these.

In the present invention, a curable composition containing both a curable compound containing an ethylenically unsaturated group and a curable resin containing a ring-opening polymerizable group can also be used.
A curable composition containing a curable compound containing an ethylenically unsaturated group (curable resin) and a curable resin containing a ring-opening polymerizable group (hereinafter, unless otherwise specified, the “curable composition” When curing these two curable resins), it is preferable that the crosslinking reaction of both curable resins proceeds. A preferable crosslinking reaction of the ethylenically unsaturated group is a radical polymerization reaction, and a preferable crosslinking reaction of the ring-opening polymerizable group is a cationic polymerization reaction. In either case, the polymerization reaction can be advanced by the action of active energy rays. Usually, a small amount of radical generator and cation generator (or acid generator) called polymerization initiators can be added and decomposed by active energy rays to generate radicals and cations to proceed the polymerization. . Although radical polymerization and cationic polymerization may be performed separately, it is preferable to proceed simultaneously.

Examples of photoacid generators that generate cations by ultraviolet rays include ionic curable resins such as triarylsulfonium salts and diaryliodonium salts, and nonionic curable resins such as nitrobenzyl esters of sulfonic acids. Various known photoacid generators such as curable resins described in “Electronic Materials for Imaging” (1997) published by the Electronics Materials Research Group can be used. Of these, diaryl iodonium salts are particularly preferred from the viewpoint of little yellow coloring, and PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , B (C ₆ F ₅ ) ₄ ^{− and the} like are preferable as counter ions. It is also a preferred embodiment to use a combination of triarylsulfonium salt and diaryliodonium salt.

  Examples of polymerization initiators that generate radicals by ultraviolet rays include known radical generators such as acetophenones, benzophenones, Michler's ketone, benzoylbenzoate, benzoins, α-acyloxime esters, tetramethylthiuram monosulfide, and thioxanthone. Can be used. Examples of the sensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, and thioxanthone compounds.

  The addition amount of the polymerization initiator is 0.1 to 15% by mass with respect to the total mass of the ethylenically unsaturated group-containing curable resin and the ring-opening polymerizable group-containing curable resin contained in the curable composition. It is preferably used in a range, and more preferably in a range of 1 to 10% by mass.

  In the present invention, it is preferable to add fine particles to the curable composition. By adding inorganic fine particles, swelling of the transparent plastic film base material by a solvent can be suppressed. Moreover, since the amount of cure shrinkage of the cured coating can be reduced by adding fine particles, it is also preferable from the viewpoint of improving adhesion to the substrate and reducing curl. As the fine particles, any of inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used. However, since the fine particles generally tend to increase haze, it is necessary to adjust the filling method in consideration of the balance of each required characteristic.

  Examples of the inorganic fine particles include silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, and aluminum oxide particles. Such inorganic crosslinked fine particles are generally hard, and by filling the hard coat layer, not only the shrinkage during curing can be improved, but also the surface hardness can be increased.

In general, inorganic fine particles have a low affinity with organic components such as the curable resin that can be used in the present invention, and therefore, when they are simply mixed, an aggregate is formed or a cured coating after curing tends to crack. There is. In the present invention, in order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles can be treated with a surface modifier containing an organic segment. The surface modifier preferably has a functional group capable of forming a bond with or adsorbing to the inorganic fine particles and a functional group having high affinity with the organic component in the same molecule.
Examples of the surface modifier having a functional group capable of binding or adsorbing to inorganic fine particles include metal alkoxide surface modifiers such as silane, aluminum, titanium, and zirconium, phosphate groups, sulfate groups, sulfonate groups, carboxylic acid groups, and the like. A surface modifier having an anionic group is preferred. Furthermore, the functional group having a high affinity with the organic component may be simply a combination of the organic component and the hydrophilicity / hydrophobicity, but a functional group that can be chemically bonded to the organic component is preferable, particularly an ethylenically unsaturated group, Or a ring-opening polymerizable group is preferable.
A preferable inorganic fine particle surface modifier in the present invention is a metal alkoxide or a curable resin having an anionic group and an ethylenically unsaturated group or an anionic group and a ring-opening polymerizable group in the same molecule.

  Representative examples of these surface modifiers include the following unsaturated double bond-containing coupling agents, phosphate group-containing organic curable resins, sulfate group-containing organic curable resins, carboxylic acid group-containing organic curable resins, and the like. It is done.

_{S-1 H 2 C = C} (X) COOC 3 H 6 Si (OCH 3) 3
_{S-2 H 2 C = C} (X) COOC 2 H 4 OTi (OC 2 H 5) 3
_{S-3 H 2 C = C} (X) COOC 2 H 4 OCOC 5 H 10 OPO (OH) 2
S-4 (H ₂ C═C (X) COOC ₂ H ₄ OCOC ₅ H ₁₀ O) ₂ POOH
_{S-5 H 2 C = C} (X) COOC 2 H 4 OSO 3 H
_{S-6 H 2 C = C} (X) COO (C 5 H 10 COO) 2 H
S-7 H ₂ C═C (X) COOC ₅ H ₁₀ COOH
S-8 3- (glycidyloxy) propyltrimethoxysilane (X = H or represents CH ₃ )

The surface modification of these inorganic fine particles is preferably performed in a solution. When inorganic fine particles are mechanically finely dispersed, a surface modifier is present together, or after finely dispersing inorganic fine particles, the surface modifier is added and stirred, or further before finely dispersing inorganic fine particles Alternatively, the surface may be modified (if necessary, heated, dried and then heated, or changed in pH), and then finely dispersed.
As the solution for dissolving the surface modifier, an organic solvent having a large polarity is preferable. Specific examples include known solvents such as alcohols, ketones and esters.

The organic fine particles are not particularly limited, but polymer particles composed of monomers having an ethylenically unsaturated group, such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyethylene, polypropylene, polystyrene In addition, polysiloxane, melamine resin, benzoguanamine resin, polytetrafluoroethylene, polycarbonate, nylon, polyvinyl alcohol, polytetrafluoroethylene, polyethylene terephthalate, polyvinyl chloride, acetylcellulose, nitro Examples thereof include resin particles such as cellulose and gelatin. These particles are preferably crosslinked.
As the fine particle disperser, it is preferable to use ultrasonic waves, dispersers, homogenizers, dissolvers, polytrons, paint shakers, sand grinders, kneaders, Eiger mills, dyno mills, coball mills, and the like. As the dispersion medium, the above-mentioned solvent for surface modification is preferably used.

  The filling amount of the fine particles is preferably 2 to 40% by volume, more preferably 3 to 30% by volume, and most preferably 5 to 20% by volume with respect to the volume of the cured film after filling.

  When a hard coat film is used for optical applications, it is preferable that the haze is low. In the present invention, the haze of the cured coating (hard coat layer) is 5% or less, preferably 2% or less, and most preferably 1.0% or less.

  In the present invention, a curable composition that is cured by irradiation with an active energy ray containing an antifouling agent in these prepared cured films or a low surface energy curable resin containing fluorine and / or silicon. By laminating an antifouling layer mainly composed of, an antifouling cured film can be obtained.

  The antifouling agent used in the present invention imparts antifouling properties such as water repellency and oil repellency to a curable substrate, such as preparation of an active energy ray curable resin composition and Any material may be used as long as it has no inconvenience when applied onto the substrate and exhibits water repellency and oil repellency on the surface of the cured film when the cured film is formed. Examples thereof include a cured resin containing fluorine and / or silicon. Moreover, the antifouling layer laminated on the cured coating used in the present invention can also be formed by a composition containing a curable resin containing fluorine and / or silicon.

  Examples of the curable resin containing fluorine and / or silicon contained in the cured film or antifouling layer used in the present invention include known fluorine curable resins and silicon curable resins, or blocks having fluorine and silicon-containing portions. A curable resin having a segment having good compatibility with the resin or metal oxide and a segment containing fluorine or silicon is preferable and added to the cured film or the antifouling layer. Thus, fluorine or silicon can be unevenly distributed on the surface.

Specific examples of these curable resins include block copolymers or graft copolymers of fluorine- or silicon-containing monomers with other hydrophilic or lipophilic monomers. Examples of the fluorine-containing monomer include perfluoroalkyl group-containing (meth) acrylic esters represented by hexafluoroisopropyl acrylate, heptadecafluorodecyl acrylate, perfluoroalkylsulfonamidoethyl acrylate, perfluoroalkylamidoethyl acrylate, and the like. Examples of the silicon-containing monomer include monomers having a siloxane group by a reaction such as polydimethylsiloxane and (meth) acrylic acid.
Hydrophilic or lipophilic monomers include (meth) acrylic acid esters such as methyl acrylate, hydroxyl-containing polyester and (meth) acrylic acid ester at the terminal, hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylic acid Examples include esters. Commercially available curable resins include acrylic oligomer defensers MCF-300, 312, 323, etc. having a perfluoroalkyl chain microdomain structure, and perfluoroalkyl group / lipophilic group-containing oligomers Megafac F-170, F -173, F-175, etc., perfluoroalkyl group / hydrophilic group-containing oligomer Megafac F-171 (Dainippon Ink Chemical Co., Ltd.), and segments with excellent surface migration and resin are compatible. Examples thereof include alkyl fluoride-based Modiper F-200, 220, 600, and 820 which are block polymers of vinyl monomers composed of segments, and silicon-based Modiper FS-700 and 710 (manufactured by NOF Corporation).

  In order to provide an antifouling layer on the cured coating, a low surface energy curable resin containing fluorine atoms is preferred. Specifically, JP-A-57-34526 and JP-A-2-19811 are preferred. And fluorinated hydrocarbon group-containing silicon curable resins and fluorinated hydrocarbon group-containing polymers described in JP-A-3-17901.

  The coating liquid for the curable composition is prepared by dissolving the above polyfunctional monomer and the polymerization initiator in a dilute organic solvent such as a ketone, alcohol or ester. Furthermore, it can be prepared by adding a surface-modified hard inorganic fine particle dispersion and a soft fine particle dispersion.

As described above, when the drying temperature is lowered in order to suppress an increase in the adhesive strength of the pressure-sensitive adhesive layer, the boiling point of the organic solvent contained as a diluent in the cured composition is 90% by mass or less when it is 130 ° C. or less. preferable. Furthermore, it is preferable that the boiling point is 90% by mass or less. Among these, if the boiling point is too low, the solvent in the coating solution evaporates at room temperature quickly and becomes difficult to handle. Therefore, the boiling point of the diluted solvent is preferably 75 ° C. or higher.
For example, ethyl acetate (bp .: 77 ° C.), ethanol (bp .: 78 ° C.), methyl ethyl ketone (MEK, bp .: 79.6 ° C.), isopropyl alcohol (IPA, bp .: 82 ° C.), 1-propanol ( bp .: 97 ° C), diethyl ketone (bp .: 102 ° C), isobutanol (bp. 108 ° C), toluene (bp .: 110 ° C), ethyl isobutyl ketone (bp .: 116 ° C), n-butanol ( bp. 118 ° C.) and the like.

[Coating]
The hard coat layer of the present invention is produced by applying a coating solution comprising a curable composition on a transparent plastic film substrate, dipping method, spinner method, spray method, roll coater method, gravure method, wire bar method, slot extrusion coater. It can be produced by coating by a known thin film forming method such as a method (single layer, multi-layer) or a slide coater method, followed by drying, ultraviolet irradiation and curing.
Drying is preferably performed under conditions where the organic solvent concentration in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The drying conditions are affected by the thermal strength of the substrate, the conveyance speed, the length of the drying process, and the like, but the one having as low an organic solvent content as possible is preferable in terms of increasing the polymerization rate.

  Moreover, when the ultraviolet curable composition which has an acrylate monomer preferably used in the present invention as a main component is irradiated with ultraviolet rays under oxygen, curing failure occurs. In order to prevent this, it is necessary to lower the oxygen concentration in the ultraviolet irradiation atmosphere. The oxygen concentration at the time of irradiation is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.3% or less.

The long roll-shaped hard coat film of the present invention provided with a hard coat layer as a functional layer can be used after being formed into a preferred shape according to various uses. For example, when used as a cover layer of an optical disc, it is used by punching into a disc shape in accordance with the disc shape.
Examples of the use of the hard coat film include an optical disc cover layer and various optical films. In particular, it is suitable for an optical disc cover layer that is read and written by blue laser light having a wavelength of 400 to 432 nm.

[Optical information recording medium]
The optical information recording medium (optical disk) of the present invention usually has a recording layer, a reflective layer, and a cover layer (protective layer) on a disc-shaped substrate.
The long roll hard coat film of the present invention is punched into a disk shape and used as a cover layer.
In the disk-shaped substrate, a guide groove (pre-groove) is usually formed for tracking of the irradiated laser beam.
For the recording layer, an organic dye or an alloy such as GeSbTe can be used. By irradiating the recording layer with laser light, the irradiated portion absorbs the light and the temperature rises locally, and the optical characteristics of the portion change due to physical or chemical changes (for example, generation of pits). Thus, information is recorded. On the other hand, reading (reproduction) of information is also performed by irradiating a laser beam having the same wavelength as the recording laser beam, and a portion where the optical characteristics of the recording layer have changed (recording portion) and a portion that has not changed ( This is done by detecting the difference in reflectance from the unrecorded portion.

  As organic dyes for the recording layer when using blue (wavelength 400 to 432 nm or 488 nm) or blue-green (wavelength 515 nm) laser light, porphyrin compounds, azo dyes, metal azo dyes, quinophthalone dyes, trimethine cyanine Examples thereof include dyes, dicyanovinylphenyl skeleton dyes, coumarin compounds, and naphthalocyanine compounds. As for the recording / reproducing method using blue or blue-green laser light including specific examples of these dyes, for example, JP-A-4-74690, JP-A-7-304256, JP-A-7-304257. JP-A-8-127174, JP-A-11-53758, JP-A-11-334204, JP-A-11-334205, JP-A-11-334206, JP-A-11-334207, JP-A-2000-43423. It is described in Japanese Patent Laid-Open No. 2000-108513, 2000-113504, 2000-149320, 2000-158818, and 2000-228028, and is also applicable to the present invention. Can do.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these examples at all.

[Preparation of surface protective film]
(Preparation of surface protective film (p-1))
And density 0.898 g / cm ³ of ethylene -α- olefin copolymer 80 wt%, density 0.923 g / cm for forming an adhesive layer resin mixture consisting of low density polyethylene 20 wt% of ^3, density 0.940 g / A surface protective film made of a laminated film having a total thickness of 60 μm and a pressure-sensitive adhesive layer thickness of 15 μm was produced by co-extrusion with cm ³ high-density polyethylene from a flat die.

(Preparation of surface protective film (p-2))
Density 0.898 g / cm ³ of ethylene -α- olefin copolymer (adhesive layer), and a high density polyethylene having a density of 0.940 g / cm ³ by co-extrusion from a flat die, a total thickness of 60 [mu] m, the adhesive A surface protective film consisting of a laminated film having an agent layer thickness of 15 μm was produced.

[Production of long roll-shaped polycarbonate film with surface protective film]
(Preparation of long roll-shaped polycarbonate film (s-1) with surface protective film)
Aromatic polycarbonate resin pellets (trade name “Panlite (registered trademark grade C-1400QJ)” manufactured by Teijin Kasei Co., Ltd.), viscosity average molecular weight 38,000 was dried with hot air at 120 ° C. for 16 hours, then dehumidified air Cooled to 30 ° C. This aromatic polycarbonate resin pellet was dissolved in a methylene chloride solvent to prepare an 18% by mass solution. The solution was passed through a filter to remove foreign matters. Furthermore, the temperature of this solution was adjusted to 15 ± 0.5 ° C. and introduced into a coat hanger die having a width of 1200 mm, and subsequently cast on a support as a liquid film of about 560 μm. The temperature (surface temperature) of the support immediately before starting casting was set to 9 ° C.

The cast polycarbonate film was dried as follows.
(1st section)
In the initial stage of drying, the substrate was heated by blowing hot air of 30 ° C. on the back surface of the support, and the atmosphere temperature of the polycarbonate film was set to 20 ° C., and the polycarbonate film was carefully dried so that deformation (leveling failure) did not occur. .
(2nd section)
Subsequently, it was dried until the ambient temperature was 45 ° C. by blowing hot air, and the methylene chloride concentration in the polycarbonate film was about 35% by mass.
(3rd section)
Subsequently, the atmosphere temperature was dried at 50 ° C. by blowing hot air, and the amount of the solvent in the polycarbonate film was adjusted to 25% by mass.
(4th section)
This compartment was dried at an ambient temperature of 55 ° C. The amount of solvent in the polycarbonate film at this time was 20% by mass.
(5th section)
In this section, the polycarbonate film was cooled together with the support in a 15 ° C. atmosphere. The amount of solvent in the polycarbonate film at the end of this step was 18% by mass.

Next, the polycarbonate film from which the polycarbonate film was peeled off was further fed into a pin tenter type dryer and conveyed while being dried.
In the pin tenter, the polycarbonate film was conveyed by holding both ends of the polycarbonate film with pins. The pin tenter was divided into six zones.
In the pin tenter, the polycarbonate film was dried from the inlet, and the width shrunk accordingly. Therefore, the pin tenter was also dried so as to narrow the rail width in accordance with the shrinkage of the width. That is, as the latter half of the pin tenter process, the hot air temperature was raised to accelerate the drying of the polycarbonate film. At this time, the rail width of the pin tenter was set so that molecular orientation of the polycarbonate film did not occur as much as possible. The hot air temperatures in the first half (1 to 3 zones) were 90 ° C., 110 ° C. and 120 ° C., the temperatures in the middle 4 and 5 zones were 130 ° C., and the polycarbonate film was separated from the pin pierced portion in these 5 zone portions. Further, the hot air temperature was 135 ° C. in 6 zones.
At the outlet of the pin tenter, the take-up tension of the polycarbonate film was taken at 0.49 MPa at about room temperature.

  Further, the membrane was passed through a roll-suspended dryer. This roll-suspended dryer was divided into two rooms, and the front hot air temperature was 135 ° C., the rear hot air temperature was 145 ° C., and the take-up tension was 0.15 MPa.

The properties of the polycarbonate film thus obtained were as follows.
The width of the obtained polycarbonate film was 1000 mm. The polycarbonate film had a thickness of 80 μm and a thickness spot of 2 μm. Thermal dimensional change rate is 0.07%, total light transmittance is 90%, content of solvent is 0.3% by mass, in-plane retardation value Re is 4 to 8 nm, surface roughness Ra is 1.8 nm, Rth value The maximum value of was 90 nm.

[Polycarbonate film evaluation method]
1) Measuring method of film thickness A sample for the entire width was taken at 1 m in the winding direction of a polycarbonate film on which no surface protective film was laminated. The film is divided into 10 cm × 10 cm grids in the width direction (direction perpendicular to the winding direction) and the winding direction (if the fraction in the width direction exceeds 50 mm, the part is also taken as a measurement sample), The thickness was measured using a micrometer manufactured by Mitutoyo Corporation at approximately the center of the grid. And the average value of the thickness of 100 measurement points was calculated | required, and this was displayed as the thickness of the film.

2) Method for measuring film thickness unevenness In the measurement method using the micrometer of 1) above, there is a possibility of overlooking thickness unevenness other than the measurement point, for example, thin streaky thickness unevenness. Continuous measurement was carried out using a film thickness tester KG601A manufactured by Co., Ltd. The measurement film was sampled as follows. That is, 10 sheets of the full width sample were continuously cut out at intervals of 5 cm in the film winding direction (total of 50 cm in the film winding direction). The thickness distribution of each sample was measured with the above-mentioned film thickness tester and recorded on a recording paper. A difference (thickness range) between the maximum value and the minimum value of the recorded thicknesses is obtained for the ten films, and the one having the maximum thickness range is displayed as a thickness unevenness of the film. did.

3) Rate of thermal dimensional change The width direction of the polycarbonate film (the film width was about 1 m) was divided into three equal parts, and a parent sample having an appropriate size was collected. Further, a total of 30 samples for measuring the thermal dimensional change rate were prepared from each of the parent samples. The size of the sample for measuring the rate of thermal dimensional change is 5 out of 10 samples from each parent sample, the film winding direction is 150 mm, the direction perpendicular to it is 10 mm, and the remaining 5 samples are The film winding direction was 10 mm, and the direction perpendicular thereto was 150 mm. And about each of the sample, the mark for a thermal dimensional change rate measurement was marked by the interval of 100 mm in the length direction of 150 mm. In this way, 15 samples for measurement were prepared in the film winding direction and 15 points in a direction perpendicular to the film winding direction (width direction). The measurement sample was suspended in a 140 ° C. thermostatic bath under no load and treated for 1 hour, then taken out to room temperature and cooled, and then the gauge interval was measured. The measurement of the dimensions was performed using a reading microscope under conditions of constant temperature and humidity and 23 ° C. and 65% RH. The dimensional change rate was obtained from 15 points in the winding direction and 15 points in the width direction as follows from the dimensions before and after the 140 ° C. heat treatment. The maximum value was displayed as the thermal dimensional change rate.
Thermal dimensional change rate = {(size before treatment) − (size after treatment)} / (size before treatment) × 100 (%).

4) Total light transmittance About 300 mm square samples were collected from three places in the width direction of the polycarbonate film (the film width was about 1 m). The total light transmittance of the sample was measured using a color difference / turbidity measuring device COH-300A manufactured by Nippon Denshoku Industries Co., Ltd. Five points were measured for each sample, and an average value of a total of 15 points for three samples in the width direction was defined as the total light transmittance.

5) Measurement of amount of solvent contained in polycarbonate film About 5 g of a polycarbonate film containing a solvent was collected, dried for 1 hour in a hot air dryer at 170 ° C., and then cooled to room temperature. At that time, the mass before and after the drying was precisely weighed with an analytical balance, and the rate of change was determined. This determined the solvent content based on solid content. Specifically, the measurement was carried out by dividing a polycarbonate film (width is about 1 m) into five equal parts in the width direction. This was carried out three times in different width directions, and the average value was obtained (the average value of 15-point measurement was displayed as the amount of solvent contained). When the mass before drying is a and the mass after drying and cooling is b, each measured value of the solvent content based on solid content can be expressed by the following equation.
{(Ab) / b} × 100 (%)

6) Measurement of in-plane retardation value Re A strip-like sample of a polycarbonate film having a total width of 40 mm in the winding direction was collected at three locations in the winding direction at intervals of 50 cm. Next, this strip-like film was cut at intervals of 40 mm to prepare a 40 mm square sample for measurement. That is, since there are three strip-shaped samples from 25 mm in length in the full width direction of the film, a total of 75 measurement samples were obtained. The in-plane retardation value Re was measured for these samples. The numerical value was displayed in the range of the Re value, and the minimum value to the maximum value were displayed. Using a trade name KOBRA-21ADH, which is a birefringence measuring instrument manufactured by Oji Scientific Instruments Co., Ltd., a measuring device was used to measure the in-plane retardation Re value by making light incident on the polycarbonate film surface in the vertical direction.

7) Measurement of retardation value Rth in the thickness direction Sampling was performed in the same manner as in the above item 6), and measurement was performed with KOBRA-21ADH. A polycarbonate film sample was rotated about its slow axis or fast axis to change the incident angle, and the retardation was measured. Refractive indexes nx, ny and nz were calculated from these data. Furthermore, Rth value = | ((nx + ny) / 2−nz) * d | (two vertical bars mean absolute values) was calculated from these values. Here, nx represents the refractive index in the winding direction, ny represents the refractive index in the direction orthogonal to the winding direction, nz represents the refractive index in the thickness direction, and d represents the thickness of the measurement film (unit: μm). . The unit of the Rth value is calculated in μm at the time of the above calculation, but is converted to the nm unit when this is displayed. In the present specification, the maximum value of the Rth value means the maximum value among them.

8) Measurement of centerline average surface roughness (Ra) The centerline average surface roughness (Ra) is a value defined by JIS-B0601, and the numerical value in this specification is a contact of Kosaka Laboratory Co., Ltd. It was measured using a formula surface roughness meter (Surfcoder, SE-30C). The measurement conditions for Ra are as follows.
Stylus tip radius: 2μm
Measurement pressure: 0.294N
Cut-off: 0.08mm
Measurement length: 1.0mm
In the same manner as the parent sample in 3) above, sampling was performed at three locations in the full width direction of the film and used for measurement. Measure the same sample 5 times, and remove the largest value of the measured value (value up to the 4th decimal place in μm unit), and obtain the remaining 4 data. The average value of 12 values was rounded off to the fifth decimal place, and the fourth decimal place was shown in nm.

  The polycarbonate film obtained as described above is laminated with a winder on the surface protective film (p-1) on the polycarbonate film with a weak adhesive surface (adhesive layer surface), nip-laminated, and a 500 m long surface. A long roll polycarbonate film (s-1) with a protective film was prepared.

(Preparation of long roll-shaped polycarbonate film (s-2) with surface protective film)
A total thickness of 60 μm made of a coextruded film of polyethylene and an ethylene / vinyl acetate copolymer (adhesive layer) for the long roll polycarbonate film (s-1) with the surface protective film, adhesive By changing to a surface protective film having a layer thickness of 15 μm, a long roll polycarbonate film (s-2) with a surface protective film having a length of 500 m was prepared.

(Preparation of long roll-shaped polycarbonate film (s-3) with surface protective film)
The long roll-shaped polycarbonate film with a surface protective film having a length of 500 m is obtained by changing the surface protective film to the surface protective film (p-2) with respect to the long roll-shaped polycarbonate film (s-1) with the surface protective film. (S-3) was created.

[Preparation of hard coat layer coating solution]
(Preparation of hard coat layer coating solution (h-1))
450 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (DPHA, manufactured by Nippon Kayaku Co., Ltd.), 210 parts by mass of isopropyl alcohol (IPA) and 140 parts by mass of methyl isobutyl ketone (MIBK) Dissolved in the mixed solvent. 12.0 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added to the resulting solution and stirred until dissolved, followed by 380 parts by mass of IPA-ST (average An isopropyl alcohol dispersion of SiO ₂ sol having a particle size of 10 to 20 nm and a solid content concentration of 30% by mass (manufactured by Nissan Chemical Co., Ltd.) and 257 parts by mass of MIBK-ST (average particle size of 10 to 20 nm, solid content concentration of 30 mass) % SiO ₂ sol methyl isobutyl ethyl ketone dispersion (Nissan Chemical Co., Ltd.) was added and stirred to obtain a mixture, which was filtered through a polypropylene filter (PPE-03) with a pore size of 3 μm for a hard coat layer. A coating solution (h-1) was prepared.

(Preparation of hard coat film)
(Example 1)
The coating speed is set to 10 m / min, the thickness after drying the hard coat coating solution on a long roll polycarbonate film (s-1) with a surface protective film having a width of 1000 mm is 3.3 μm, and the coating width is 980 mm. As described above, it was applied using a bar coater, dried at 70 ° C. for 1 minute, irradiated with ultraviolet rays to cure the hard coat layer, and wound up the hard coat film by 300 m.

  The base material or the drying temperature was changed as shown in Table 1 with respect to Example 1, and Example Samples 2-7 and Comparative Samples 1-2 were produced. In Comparative Example 3, the surface protective film was peeled off by hand immediately before applying the hard coat solution.

(Evaluation of hard coat film)
The following evaluation was performed for each hard coat film. The evaluation results are shown in Table 1.
(1) Rewinding Two-stage evaluation was performed according to the following criteria.
○: Good roll appearance,
×: Wrinkled.

(2) Steel wool scratch resistance evaluation A rubbing test was performed using a rubbing tester under the following conditions.
Sample humidity control conditions: 25 ° C., 60% RH, 2 hours or more. Rubbing material: Steel wool (manufactured by Nippon Steel Wool, grade # 0000) was wound around the rubbing tip (1 cm × 1 cm) of a tester that was in contact with the sample, and the band was fixed so as not to move. Travel distance (one way): 13 cm. Rubbing speed: 13 cm / sec. Load: 1.96 N / cm ² . Tip contact area: 1 cm × 1 cm. Number of rubs: 50 round trips.
Oily black ink was applied to the back side of the rubbed sample and visually observed with reflected light, and scratches on the rubbed portion were evaluated in two stages according to the following criteria.
○: Scratches not visible
X: Scratches are visible.

(3) Peelability A 1000 mm width (full width) and a length of 30 cm were sampled from the finished long roll-shaped hard coat film with a surface protective film, and the surface protective film was peeled off and evaluated in three stages.
A: The protective film can be easily peeled off without resistance.
○: Somewhat resistant but the protective film was peeled off,
×: There is considerable resistance, and there is a scratch when trying to force it off.

(4) Adhesive force The finished long roll-shaped hard coat film with a surface protective film was sampled and peeled by 180 ° at a pulling speed of 300 mm / min for a 25 mm wide film, and the tension measured at that time was taken as the adhesive force.

From the results shown in Table 1, the following is clear.
When using a polycarbonate film to which a general surface protection film made by coextrusion of polyethylene and ethylene / vinyl acetate copolymer is used, the surface protection film is difficult to peel off at a drying temperature of 70 ° C. or more (Comparative Example) 1 and 2).
Even when the surface protective film was used, the film could be peeled off at a drying temperature of 60 ° C. or lower, and was easily peeled off at a drying temperature of 50 ° C. or lower (Examples 4 and 5).
The surface protective film using the pressure-sensitive adhesive composed only of the ethylene-α-olefin copolymer was peeled off relatively easily at a drying temperature of 70 ° C. (Examples 6 and 7).
A surface protective film using a mixture of an ethylene-α-olefin copolymer and low-density polyethylene as an adhesive has an effect of suppressing an increase in adhesive force in the drying step, and the effect is obtained only from the ethylene-α-olefin copolymer. Even when the drying temperature was higher than that of the pressure-sensitive adhesive, the surface protective film could be easily peeled off (Examples 1 and 2).
If the surface protective film was peeled off before the hard coat was formed, the winding could not be performed well (Comparative Example 3).

[Application to optical recording disc]
(Production of optical recording disk)
[Comparative Example 20]
Example 1 described in paragraphs 0048 to 0054 of JP-A-2003-267397 was used as Comparative Example 20 of the present invention. The cover layer film is a polycarbonate film (with a single-sided release film, manufactured by Teijin Pure Ace, thickness: 80 μm, surface roughness of the surface with the release film 250 nm). The specific production method of the optical information recording medium is the same as that in Example 21 below except that the polycarbonate is used as the cover film.

[Example 21]
<Production of optical information recording medium>
A polycarbonate resin (polycarbonate manufactured by Teijin Limited, trade name: Panlite AD5503) substrate having a spiral groove (depth 100 nm, width 120 nm, track pitch 320 nm), thickness 1.1 mm, diameter 120 mm was injection molded. On the surface of the obtained substrate having a groove, Ag was sputtered to form a light reflecting layer having a thickness of 100 nm (light reflecting layer forming step).

Thereafter, 20 g of Orazol Bull GN (phthalocyanine dye, manufactured by Ciba Specialty Chemicals Co., Ltd.) was added to 1 liter of 2,2,3,3-tetrafluoropropanol and dissolved by sonication for 2 hours. Then, a coating solution for forming a recording layer was prepared. The prepared coating solution was applied onto the light reflecting layer by spin coating under the conditions of 23 ° C. and 50% RH while changing the rotation speed from 300 to 4000 rpm. Thereafter, the film thickness of the recording layer formed by storing at 23 ° C. and 50% RH for 1 to 4 hours was 100 nm (recording layer forming step). Then, ZnS—SiO ₂ was sputtered to a thickness of 5 nm on the recording layer to form an intermediate layer.

<Preparation of cover layer>
[Preparation of adhesive coating solution]
Acrylic copolymer (solvent: ethyl acetate / toluene = 1/1) and isocyanate crosslinking agent (solvent: ethyl acetate / toluene = 1/1) were mixed at 100: 1 (mass ratio) and adhered. Agent coating liquid A was prepared.

[(A) A step of continuously providing a pressure-sensitive adhesive layer containing a crosslinking agent on the surface of a hard coat film wound in a roll shape, and (b) a cover film provided with the pressure-sensitive adhesive layer again in a roll shape Winding process]
First, an adhesive layer having a thickness of 17 μm was provided on the surface of the hard coat film by using the adhesive layer setting device shown in FIG.
The polyethylene release film wound around the roll 1 was fed in the direction of the arrow, and the adhesive coating solution A was applied to the surface of the release film using the installed application part 2 (application process). Thereafter, the release film on which the pressure-sensitive adhesive coating layer was formed was dried at 100 ° C. by the drying means 3 installed in the drying area (drying process), and a release film provided with the pressure-sensitive adhesive layer was obtained. Then, the release film provided with the adhesive layer is further conveyed, and the surface of the cover film (long roll hard coat film of Example 1: 83 μm, with a single-sided surface protective film) fed from the roll 4 by the roll 6. The protective film was wound up while being peeled off, and bonded in the bonding area a so that the polycarbonate surface of the hard coat film after peeling off the surface protective film and the adhesive layer were in contact with each other (bonding step). And the roll 5 was wound together with the release film provided with the adhesion layer, and the hard coat film (winding process).

[(C) Step of holding until the crosslinking reaction of the adhesive layer is substantially completed]
Thereafter, the roll 5 co-rolled with the release film and the cover film provided with the adhesive layer was held for 72 hours in an atmosphere of 23 ° C. and 50% Rh. This “72 hours” means that the pressure-sensitive adhesive layer in this example was measured with the infrared spectral absorption spectrum over time in the above atmosphere, and an absorption peak appearing in the vicinity of 2275 to 2250 cm ⁻¹ derived from isocyanate was substantially present. This is the elapsed time until it disappears, and is the time corresponding to “until the crosslinking reaction of the adhesive layer is substantially completed” in this example. In this step, the infrared spectral absorption spectrum was measured by the FT-IR single reflection method under the following conditions.
Measuring machine: Nexus 670 manufactured by Thermo Nicole Japan
Measurement accessory: OMNI-Sampler One-time reflection type horizontal ATR device Integration count: 4 cm ^-1 32 times Detector: MCT-A (high sensitivity detector)

[(D) A step of punching the cover film provided with the adhesive layer into a disk shape, and (e) a step of stacking and holding the cover film provided with the disk-like adhesive layer substantially horizontally.
A release film and a cover film provided with the co-rolled adhesive layer were fed from the roll 5 and punched into the same shape as the substrate of the optical recording disk. As shown in FIG. 2, the laminated body of the release film and the cover film having the punched adhesive layer is fitted into a stock jig 20 having an outer diameter slightly smaller than that of the center hole, and approximately 50 sheets. Laminated. This state was maintained for 1 hour.

  Thereafter, each sheet was taken out, the release film on the pressure-sensitive adhesive layer side was peeled off, and the intermediate layer and the pressure-sensitive adhesive layer were bonded together by a pressing means using a roller to produce an optical information recording medium.

[Comparative Example 22]
The long roll hard coat film of Example 21 was changed to the film of Comparative Example 2 to obtain a Comparative Example 22 sample.

(Sample evaluation)
1. Evaluation of scratches When 100 samples prepared above were visually inspected, only Comparative Example 22 had three scratches. It was confirmed that the present invention can prevent scratches.

2. Abrasion resistance The surface of the cover layer side of the sample was evaluated using a steel wool of # 0000, and the extent to which the scratches became visible when rubbed while applying a load of 1.96 N / cm ² was evaluated. Evaluation criteria are: ○: a state where no trace is visible even after rubbing 100 times, and x: a state where a trace is visible after less than 30 times. The evaluation results were as follows.
Example 21: Yes,
Comparative Example 20: ×,
Comparative Example 22: ◯.

  From the above results, it can be seen that the hard coat film of the present invention has no scratches and is resistant to scratches, and is therefore suitable as a protective film for optical recording disks.

It is a schematic sectional drawing of the adhesion layer installation apparatus used for the method of providing an adhesive layer continuously, peeling off the surface protection film of a long roll-shaped hard coat film in an Example. It is the schematic which shows the state which laminated | stacked the disk-shaped cover film in which the adhesion | attachment layer was provided in the holding means substantially horizontally.

Explanation of symbols

1, 4, 5, 6 Roll 2 Application means 3 Drying means 10 Base 20 Stock jig f1 Release film f2 Hard coat film f3 Hard coat film f4 provided with a disk-like adhesive layer Surface protective cover film

Claims (11)

  It has a functional layer on one side of the transparent plastic film base, and a surface protective film is bonded to the other side. The adhesive force between the surface protective film and the transparent plastic film base is 100 to 500 mN / 25 mm. A long roll-like functional film characterized by being   The long roll-like functional film according to claim 1, wherein the transparent plastic film substrate is a polycarbonate film produced by a casting method.   The long roll-like functional film according to claim 1 or 2, wherein the transparent plastic film substrate has a thickness of 70 to 120 µm. The surface protective film and the transparent plastic film base material are bonded via an adhesive layer,
50-90 mass% of ethylene-α-olefin copolymer having a density of 0.898-0.920 g / cm ³ polymerized using a single-site catalyst, and a density polymerized using a Ziegler catalyst The long roll-like functional film according to any one of claims 1 to 3, comprising a mixture of 10 to 50% by mass of low density polyethylene of 0.918 to 0.925 g / cm ³ as a main component. The surface protective film and the transparent plastic film base material are bonded via the adhesive layer.
The pressure-sensitive adhesive layer has, as a main component, an ethylene-α-olefin copolymer having a density of 0.898 to 0.920 g / cm ³ polymerized using a single site catalyst. The long roll-like functional film according to any one of the above.   The long roll according to any one of claims 1 to 3, wherein the surface protective film is a surface protective film with an adhesive layer produced by co-extrusion of polyethylene and an ethylene / vinyl acetate copolymer. Functional film.   The long roll hard coat film according to any one of claims 1 to 6, wherein the functional layer is a hard coat layer.   The long roll-shaped hard coat film according to claim 7, which is used as a cover layer of an optical information recording medium which is read and written by a blue laser beam having a wavelength of 400 to 432 nm. It is a manufacturing method of the elongate roll-shaped functional film in any one of Claims 1-8,
A transparent plastic film in the form of a long roll with a surface protective film bonded is transported in the length direction from the feeder via a guide roll, and the side opposite to the surface of the transparent plastic film with the surface protective film bonded On the surface, a curable composition is applied, dried and cured to form a functional layer, and the method includes a step of winding the surface protective film while the surface protective film is being bonded. Method.   The method for producing a long roll-like functional film according to claim 9, wherein the drying temperature when forming the functional layer is 65 ° C or lower.   An optical information recording medium comprising a hard coat film obtained from the long roll-shaped hard coat film according to claim 8 as a cover layer.

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