JP2005313532A - Long roll-shaped optical film, long roll-shaped optical hard coat film and optical disk loaded with optical hard coat film as cover layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of thickness irregularity formed in a hard coat layer when the long roll-shaped optical film is manufactured using a polycarbonate film as a base material. <P>SOLUTION: When the long roll-shaped optical hard coat film based on the polycarbonate film is manufactured using a polycarbonate film wound body with a surface protective film, the cured layer of the polycarbonate film is formed so that the pressure-sensitive adhesive of the surface protective film is not bonded to a surface to be coated to obtain the long roll-shaped optical hard coat film wherein an inference fringe is not observed in relation to the film thickness irregularity of the cured layer and the thickness of the cured layer is uniform. Further, the optical disk loaded with this hard coat film as the cover layer is also disclosed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a long roll-shaped optical film in which a smooth polycarbonate film is laminated with a uniform thickness, using a smooth polycarbonate film for use in optical applications such as a cover layer of an optical disk or a surface protective layer of a display, The present invention relates to a long roll optical hard coat film and an optical disc on which the optical hard coat film is mounted as a cover layer.

  Polycarbonate is excellent in transparency, lightweight, and has good impact properties. Therefore, it is widely studied in various industries, building materials, decorative materials, and optical materials as an alternative to glass. In particular, the polycarbonate film produced by the casting method (solvent cast method) is used as a base material for optical functional films, despite its high optical anisotropy, so that its use has expanded year by year. Yes.

  In recent years, a plastic cover film of about 100 μm has been studied as a cover layer of a high-density optical disk using a blue-violet laser light source. However, a substrate having a thermal expansion coefficient approximate to that of the substrate is preferable. Things are used. Therefore, since a polycarbonate resin is generally used as a resin substrate of an optical disk at present, practical examination is being promoted mainly for a polycarbonate film in this light-transmitting base film.

  By the way, a functional layer of an optical functional film based on a polycarbonate film is formed by applying a curable composition containing a functional material, a curable resin and an organic solvent to the base film and curing it. The

  A more specific explanation will be given by taking a hard coat film based on a polycarbonate film as an example. Polycarbonate films have the disadvantages of low surface hardness and poor scratch resistance. Therefore, the surface hardness has been increased by providing a hard coat layer on the surface of the polycarbonate film.

  As a method of forming a hard coat layer on a plastic film substrate, a curable organic compound such as a polyfunctional (meth) acrylic monomer, a photopolymerization initiator is the main component, and an organic solvent as a diluent is added to improve coating properties. The method of applying the ultraviolet curable resin composition to a plastic film, performing the drying process, and continuously irradiating with ultraviolet rays in a roll-to-roll manner has high productivity and is widely used.

  On the other hand, the polycarbonate film for optical use generally has a flat surface, so it cannot be rolled up into a roll layer as it is, which forms irregularities on the surface while maintaining high light transmittance. This is because it is difficult to impart slipperiness. Therefore, in order to obtain a long roll polycarbonate film for optical use, a so-called surface protective film is laminated on the polycarbonate film.

  This surface protective film generally has a structure made by coextrusion of an adhesive layer made of polyethylene and ethylene-vinyl acetate copolymer, and the adhesive layer surface is weakly adhesive to the polycarbonate film surface. The film winding layer is manufactured by attaching the films just before winding, niping them weakly and winding them up with a winder.

  When a long roll-shaped hard coat film is produced using a polycarbonate film as a base material, it is produced using a long roll-shaped polycarbonate film in which the surface protective film produced as described above is bonded with an adhesive. It is common.

As what described such a prior art, the patent document 1 and the patent document 2 which are shown below are mentioned, for example.
JP 2001-243658 A JP 2001-243659 A

By the way, when producing the elongate roll-shaped optical film which formed the hard-coat layer on the polycarbonate film using the polycarbonate film with a surface protective film, it turned out that the problem of thickness nonuniformity generate | occur | produces in a hard-coat layer.
Optical hard coat films are required to have a uniform hard coat layer thickness. When the hard coat layer has uneven thickness, for example, when used as a cover layer of an optical disc, it causes noise. Moreover, when used as a surface protective film for a display, uneven thickness distorts the image and significantly reduces its quality.

However, no invention has been reported so far in which the thickness unevenness of the cured layer is reduced when the cured layer is laminated on the polycarbonate film with the surface protective film.
Although it is suggested in Patent Document 1 and Patent Document 2 that the adhesive layer surface material of the polycarbonate film with the surface protective film may be transferred to the polycarbonate film, curing of the hard coat layer produced using the polycarbonate film with the surface protective film is suggested. There is no description of the cause and improvement of the film thickness unevenness of the layer.

  In view of the above, an object of the present invention is to provide a long roll-like optical film provided with a uniform cured layer using a polycarbonate film having a high smoothness and requiring a surface protective film for winding as a substrate. In particular, it is to provide a long roll-shaped optical hard coat film, and another object of the present invention is to provide an optical disc in which an optical hard coat film obtained from the long roll-shaped optical hard coat film is mounted as a cover layer. There is.

  As a result of intensive studies, the present inventors have found that the cause of uneven thickness of the cured layer is due to the secondary transfer of the pressure-sensitive adhesive, and found that the unevenness of thickness can be prevented by preventing this transfer. It came to.

  That is, the long roll-shaped optical film of the present invention is a long roll-shaped optical film in which a cured layer is laminated on a substrate made of a polycarbonate film, and interference fringes due to film thickness unevenness of the cured layer are present. It is a long roll-shaped optical film that is not observed.

  The long roll optical film of the present invention is a long roll optical film in which a cured layer is laminated on a substrate made of a polycarbonate film, and uses a polycarbonate film wound layer with a surface protective film. When the long roll-shaped optical film is produced, the long roll-shaped optical film is produced so that the adhesive of the surface protective film does not adhere to the surface on which the cured layer of the polycarbonate film is to be applied.

  Moreover, the long roll-shaped optical film of the present invention is a long roll-shaped optical film in which a polycarbonate film substrate is produced by a casting method, and a long roll whose hardened layer has a thickness of 1 to 10 μm. Shaped optical film.

  The long roll-shaped optical hard coat film of the present invention is a hard coat layer whose hardened layer has scratch resistance against steel wool, and the optical disk of the present invention is such a long roll-shaped optical hard coat film. An optical disk on which an optical hard coat film obtained from a hard coat film is mounted as a cover layer.

More specifically, the above problem can be achieved by the following means.
1. A cured layer having a thickness of 1 to 10 μm is laminated on the polycarbonate film substrate, and the surface roughness Ra of the surface on which the cured layer of the polycarbonate film substrate is not laminated is 5.0 nm or less, and the film is evaluated by the following evaluation method. A long roll-shaped optical film characterized by having no thickness unevenness.
(1) When the refractive index difference between the polycarbonate film substrate and the cured layer is 0.03 or more The substrate surface of any sample cut out to 5 × 5 cm from the long roll-shaped optical film is painted black, and three cured layers are formed. A long-roll optical film characterized in that no interference fringes that can be formed into a ring shape due to a dark color portion or a light color portion are observed when observed under a fluorescent lamp.
(2) When the refractive index difference between the polycarbonate film substrate and the cured layer is less than 0.03 Black the substrate surface of any sample cut out 5 × 5 cm from the long roll optical film, and the cured layer is Fizeau A long roll-shaped optical film characterized in that no interference fringes that can be formed into a ring shape by dark color portions or light color portions are observed when observed using an interferometer.
2. 2. The long roll-shaped optical film as described in 1 above, which is prepared by feeding a wound layer body in which a polycarbonate film and a surface protective film are co-wound, and continuously laminating a cured layer.

3. After laminating a polycarbonate film and a surface protective film without using a sticky adhesive (adhesive) between them, using a rolled up polycarbonate film roll, removing the surface protective film, and laminating a cured layer 3. The long roll optical film as described in 2 above, which is formed by winding.
4). 4. The long roll-shaped optical film as described in 3 above, wherein the surface protective film is a polyethylene terephthalate film.
5). 5. The long roll-shaped optical film as described in 4 above, wherein the Young's modulus in the vertical and horizontal directions of the polyethylene terephthalate film is 450 kg / mm ² or more (4.41 GPa or more).
6). 5. The long roll optical film as described in 4 above, wherein the Young's modulus in the vertical and horizontal directions of the polyethylene terephthalate film is 550 kg / mm ² or more (5.39 GPa or more).
7). The long roll optical film according to any one of 4 to 6, wherein the surface protective film has a thickness of 10 to 50 µm.
8). 8. The long roll-shaped optical film according to any one of 4 to 7, wherein the surface protective film has a surface roughness Ra of 10 to 30 nm.

9. A surface protective film and a polycarbonate film are adhered with an adhesive to produce a rolled up polycarbonate film layered body, and the cured layer is formed by feeding out the polycarbonate film wound layered body and laminating the cured layer. The long roll-shaped optical film as described in 2 above.
10. The surface protective film with the pressure-sensitive adhesive layer is not wound up after the pressure-sensitive adhesive layer is laminated, and a polycarbonate film wound layer body is produced by sticking to a polycarbonate film, and the cured film layer is sent out from the polycarbonate film wound layer body. 10. The long roll optical film as described in 9 above, wherein a cured layer is formed by winding after lamination.
11. Adhesive layer of the surface protective film with pressure-sensitive adhesive layer is directly laminated to the polycarbonate film without being laminated, and rolled up to produce a polycarbonate film wound layer, which is then sent out and cured 10. The long roll-shaped optical film as described in 9 above, wherein a cured layer is formed by winding up the layers after lamination.
12 The surface protective film is laminated with a pressure-sensitive adhesive layer, and then the release paper or release film is attached to the pressure-sensitive adhesive layer and wound up to prevent the transfer of the pressure-sensitive adhesive. The release paper or release film is peeled off and applied to the polycarbonate film. 12. The long roll according to 11 above, wherein a polycarbonate film wound layer body is prepared by attaching and winding, and the cured layer is formed by feeding out the polycarbonate film wound layer body and winding the laminated cured layer after winding. Optical film.
13. The surface protective film with a pressure-sensitive adhesive layer is wound up so that the surface opposite to the pressure-sensitive adhesive layer is directly touched to produce a surface protective film-wound layer body, and the surface protective film-wound layer body is fed out and adhered to a polycarbonate film. 10. The polycarbonate film wound layer body is produced by co-winding with insulating paper or an insulating film, the polycarbonate film wound layer body is fed out and formed by laminating a cured layer and then winding it. Long roll optical film.
14 The surface protective film with a pressure-sensitive adhesive layer is wound up so that the surface opposite to the pressure-sensitive adhesive layer is directly touched to produce a surface protective film-wound layer body, and the surface protective film-wound layer body is fed out and adhered to a polycarbonate film. A polycarbonate film wound layer body is produced by winding, the polycarbonate film wound layer body is fed out, subjected to a treatment for removing the adhesive adhered to the coating layer, and then formed by winding the cured layer after lamination. 10. The long roll-shaped optical film as described in 9 above.

15. 15. The long roll optical film as described in any one of 9 to 14 above, wherein the surface protective film is produced by coextruding polyethylene and polyvinyl acetate.
16. An ethylene-α-olefin copolymer 50 to 90 having a density of 0.898 to 0.920 g / cm ³ in which the pressure-sensitive adhesive layer for bonding the surface protective film and the polycarbonate film substrate is polymerized using a single site catalyst. The pressure-sensitive adhesive is characterized in that it is a pressure-sensitive adhesive mainly composed of a mixture of 10% to 50% by mass of low-density polyethylene having a density of 0.918 to 0.925 g / cm ³ polymerized using a Ziegler catalyst. The long roll optical film in any one of -14.
17. A long roll-shaped polycarbonate film bonded with a surface protective film is transported in the length direction while the surface protective film is bonded from a feeding machine via a guide roll, and the surface on which the surface protective film of the polycarbonate film is bonded Any one of 9 to 16 above, wherein the curable composition is applied, dried and cured on the opposite surface, laminated with a functional cured layer, and wound with the surface protective film bonded. A long roll-shaped optical film according to claim 1.

18. 18. The long roll optical film as described in any one of 1 to 17 above, wherein the polycarbonate film is an aromatic polycarbonate having bisphenol A as an aromatic dihydroxy component.
19. The long roll optical film as described in any one of 1 to 18 above, wherein the polycarbonate film substrate (without a surface protective film) has a thickness unevenness of 4 μm or less.
20. 20. The long roll-shaped optical film as described in any one of 1 to 19, wherein the polycarbonate film substrate (without a surface protective film) has a thermal dimensional change rate of 0.07% or less.
21. 21. The long roll-shaped optical film as described in any one of 1 to 20 above, wherein the polycarbonate film substrate (without a surface protective film) has an in-plane retardation value of 15 nm or less.
22. The long roll optical film according to any one of 1 to 21, wherein the polycarbonate film substrate (without a surface protective film) has a thickness of 50 to 100 µm.
23. The long roll optical film as described in any one of 1 to 22 above, wherein the polycarbonate film substrate (without a surface protective film) has a thickness of 70 to 90 μm.
24. 24. The long roll-shaped optical film as described in any one of 1 to 23 above, wherein the polycarbonate film substrate (without a surface protective film) has a total light transmittance of 90% or more.
25. The long roll optical film as described in any one of 1 to 24 above, wherein the polycarbonate film substrate (without a surface protective film) has a residual solvent amount of 0.3% by mass or less.
26. 26. The long roll optical film as described in any one of 1 to 25 above, wherein the polycarbonate film substrate (without a surface protective film) has a retardation value (Rth value) in the thickness direction of 100 nm or less.
27. The long roll optical film as described in any one of 1 to 26 above, wherein the polycarbonate film substrate (without a surface protective film) has a surface roughness Ra of 5.0 nm or less on both sides.
28. 28. The long roll-shaped optical film as described in any one of 1 to 27, wherein the polycarbonate film substrate is produced by a casting method (solvent cast method).

29. 29. The long roll optical film according to any one of 1 to 28, wherein the cured layer is formed by applying, drying and curing a curable composition.
30. 30. The long roll optical film according to any one of 1 to 29, wherein the cured layer contains a curing agent and an organic solvent.
31. 31. The long roll optical film as described in 1 to 30 above, wherein the curable composition is an active energy ray curable composition.
32. The long roll optical film as described in any one of 1 to 31 above, wherein the curable composition is an ultraviolet curable composition.
33. The long roll-shaped optical film as described in 1 to 32 above, wherein the thickness of the cured layer is 1.0 to 4.0 μm.
34. The long roll optical film as described in 1 to 33 above, wherein the thickness of the cured layer is 2.5 to 4.0 μm.
35. A hard coat layer having scratch resistance, characterized in that no traces are visible when the functional surface is rubbed 10 times with # 0000 steel wool with a load of 1.96 N / cm ^2. The long roll-shaped optical hard coat film according to any one of 1 to 35.

36. 36. The long roll-shaped optical hard coat film as described in 35 above, which is used as a cover layer of an optical disk which is read and written by blue laser light having a wavelength of 400 to 432 nm.
37. 37. An optical disc on which a hard coat film using the long roll-shaped optical hard coat film for optical disc described in 36 is mounted as a cover layer.

  According to the present invention, it is possible to provide a long roll-shaped optical film, particularly a long roll-shaped hard coat film having a polycarbonate film as a base material and a uniform thickness of the cured layer. An optical disc mounted as can be provided.

Hereinafter, a long roll-shaped functional film, particularly a hard coat film, using a long roll-shaped polycarbonate film having a non-uniform thickness in the functional layer as a base layer is protected by the surface protective film of the present invention. This will be described in detail.
In the present specification, when a numerical value represents a physical property value, a characteristic value, etc., the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”. . In the present specification, for example, descriptions of “(meth) acryloyl”, “(meth) acrylate”, “(meth) acrylic acid” and the like are “acryloyl and / or methacryloyl”, “acrylate and / or methacrylate”, respectively. ”,“ Acrylic acid and / or methacrylic acid ”.

  In general, a polycarbonate film for optical use, which is required to have a very flat surface, does not slip as it is because of its high flatness, and usually cannot be wound into a roll to form a wound layer. Therefore, in order to obtain a polycarbonate film wound body for optical use, generally, a surface protective film (protect film) having adhesiveness is laminated on a polycarbonate film. That is, a very flat polycarbonate film for optical use is laminated with a surface protective film having an adhesive surface to protect the surface, and at the same time, the opposite surface of the surface protective film is moderately roughened and slips. As an easy structure, this laminated film can be easily rolled up in a roll shape. Such a surface protective film has a structure formed by co-extrusion of polyethylene and a polymer such as polyvinyl acetate, and the surface on the polyvinyl acetate side is sticky to the polycarbonate film surface. A film layer is manufactured by pasting films just before winding and niping them weakly and winding them with a winder. (See WO03 / 004270A1)

When the curable composition composed mainly of acrylate and organic solvent is applied to the surface of the polycarbonate film with the surface protective film thus prepared, the surface of which is not adhered, dried and cured, and the hard coat layer is laminated, Was found to occur.
This thickness unevenness is caused by interference fringes by peeling the surface protective film and painting the surface of the polycarbonate film that is not laminated with black magic ink, etc., and observing the cured layer under a three-wavelength fluorescent lamp. Can be recognized. Such unevenness of the cured layer becomes a very big problem in the optical film. For example, when the above hard coat film is used as a cover layer of an optical disc, it causes a large output fluctuation when a signal is input / output. Further, when used as a surface protective film for a display, the image is distorted, and the quality thereof is remarkably lowered.

  Based on the experimental results, such as non-thickness in the polycarbonate film with no surface protective film bonded, this thickness non-uniformity occurs when the adhesive surface of the surface protective film is brought into contact with the polycarbonate film. The cause of this is considered to be non-uniform secondary transfer of the pressure-sensitive adhesive of the surface protective film. The secondary transfer here is considered to occur as follows. When a surface protective film having an adhesive on one surface is wound up without using a release sheet or the like, the adhesive surface comes into contact with the other surface of the surface protective film, and primary transfer of the adhesive occurs. Next, when a surface protective film on which the primary transfer of the adhesive has occurred is bonded to the plastic film on the surface opposite to the adhesive surface, and the bonded film is wound up without using a release sheet, the primary The surface protective film surface on which the transfer is occurring comes into contact with the surface of the plastic film that is not bonded to the surface protective film, and secondary transfer of the adhesive occurs on the surface of the plastic film. In general, it is considered that the transfer of the pressure-sensitive adhesive from such a surface protective film does not occur, but it has been reported in JP-A-2001-243659 [0027] to [0028] that the primary transfer of the pressure-sensitive adhesive was observed. ing. Furthermore, since the transfer to the coated surface occurs through the primary transfer of the pressure-sensitive adhesive to the opposite surface of the surface protective film, the transfer amount becomes even smaller. Since the amount is very small, transfer is likely to be non-uniform, and it is considered that there is a difference in surface energy between the portion where the adhesive is transferred and the portion where the adhesive is not transferred, the paintability is local, and the film thickness is uneven.

  A drastic method to prevent such unevenness is to prevent the adhesive from being transferred to the coated surface of the plastic film, and to this end, the adhesive should not be transferred to the back surface (the surface opposite to the adhesive) of the surface protective film. It is.

The methods for not transferring the adhesive can be broadly divided into the following two methods.
1) Wind up the polycarbonate film with a surface protective film that does not use an adhesive. 2) Do not allow the adhesive layer to contact the surface of the surface protective film where the adhesive layer is not laminated.
1. Adhere to polycarbonate film without winding after adhesive layer lamination
2. Use release paper or release film to wind up the surface protection film
3. Use insulating paper or insulating film to wind up polycarbonate film with surface protective film

In addition to this, as a method for preventing coating unevenness due to transfer, the following method of removing the adhesive once transferred can be considered.
3) A method of laminating the cured layer after removing the pressure-sensitive adhesive transferred to the surface of the surface protective film where the pressure-sensitive adhesive layer is not laminated.

The method 1) is a method in which a surface protective film is laminated on a polycarbonate film without using a pressure-sensitive adhesive to produce a wound wound layer body, and a cured layer is laminated using the wound layer body as a base material.
Specifically, a method using a wound layer body disclosed in JP-A-2001-243659 as a substrate can be mentioned. That is, it is a method of using a wound layer body, characterized in that a surface protective film made of polyethylene terephthalate is laminated on a polycarbonate film without using an adhesive and wound up, as the polycarbonate film substrate of the present invention.

The method 2) is a method in which the pressure-sensitive adhesive layer is not brought into contact with the surface of the surface protective film on which the pressure-sensitive adhesive layer is not laminated, and the method classified here can be further classified into two methods.
A specific example will be described. As the surface protective film, for example, a surface protective film prepared by coextrusion with an adhesive layer made of polyethylene and an ethylene-vinyl acetate copolymer is used. This surface protective film usually has no release paper or release film, and is once wound up and shipped so that polyethylene and the pressure-sensitive adhesive are directly and alternately layered (for example, like a commercially available cellophane tape). In the manufacturing process of the plastic film substrate used in the present invention, the surface protective film is wound up while being peeled off, stuck to the plastic film surface, niped weakly, and then wound up with a winder to protect the surface protective film. Manufactures laminated plastic film layers.

As described above, it is considered that the pressure-sensitive adhesive layer is transferred to the opposite surface of the surface protective film when the surface protective film is wound up so that the polyethylene film and the pressure-sensitive adhesive layer are alternately formed like a commercially available cellophane tape. Therefore, in order to avoid the transfer of the pressure-sensitive adhesive layer, a method in which the pressure-sensitive adhesive layer is not brought into contact with the opposite surface of the surface protective film can be considered. This method is further classified into the following methods.
Method 1 is a method in which a pressure-sensitive adhesive layer is laminated on a surface protective film and then adhered to a polycarbonate film without being wound up by itself.
The method of 2. is to use a release paper or a release film when winding up the surface protective film with the pressure-sensitive adhesive layer.
In the method of 3., a polycarbonate film with a surface protective film is placed between a paper or a film (herein referred to as insulating paper or insulating film) so that the opposite surface of the surface protective film to which the adhesive has been transferred and the coated surface of the substrate do not directly touch each other. ).

The method 3) is a method of laminating the cured layer after removing the pressure-sensitive adhesive transferred to the surface of the surface protective film where the pressure-sensitive adhesive is not laminated.
In this method, it is necessary to remove the pressure-sensitive adhesive layer before the polycarbonate film wound layer with the surface protective film is sent out and the cured layer is laminated. The method for removing the pressure-sensitive adhesive is not particularly limited, and examples thereof include a method of washing the coated surface with a solvent that dissolves the pressure-sensitive adhesive, and a method of transferring and removing using a pressure-sensitive adhesive roll. Solvents that dissolve the adhesive need to dissolve the adhesive and do not attack the surface of the polycarbonate film, and include organic solvents such as isopropyl alcohol.

It is generally used as a method for washing a film with an organic solvent. A method of immersing and cleaning the film in an organic solvent can be used.
When it is necessary to wind with the surface protective film attached, a method of applying an organic solvent on one side and then drying is preferable without bringing the organic solvent into contact with the surface protective film.

[Polycarbonate film substrate]
The thickness of the polycarbonate film used in the present invention is preferably 20 to 300 μm, more preferably 50 to 200 μm, and particularly preferably 70 to 120 μm. Furthermore, when a functional film is used as a cover layer of an optical disc, the thickness of the film is most preferably 70 to 90 μm. If the thickness of the base film is too thin, the film strength is weak, and if it is thick, the rigidity becomes too large.
“Transparent” of the transparent substrate means that the light transmittance in the visible light region is 80% or more, and preferably 90% or more.
The film forming method may be a melting method or a casting method (solvent casting method), but in general, the casting method has low optical anisotropy, and the base material of an optical film, particularly a cover film for an optical disc. As preferred.

(Polycarbonate film material)
The polycarbonate that can be used for the plastic film according to the present invention is preferably a polycarbonate having 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) as a main aromatic dihydroxy component.

  The polycarbonate here refers to 2,2-bis (4-hydroxyphenyl) propane as a main aromatic dihydroxy compound, and a carbonate bond-forming compound such as phosgene and diphenyl carbonate in a solution state, bulk, This refers to a polymer obtained by reacting in a molten state.

  The proportion of 2,2-bis (4-hydroxyphenyl) propane in the aromatic dihydroxy compound used is at least 80 mol%, preferably 90 mol% or more, and more preferably 100 mol%. Specific examples of the aromatic dihydroxy compound used at 20 mol% or less include the following compounds.

  1,1-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3- Bis (hydroxyaryl) alkanes such as bromophenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, Bis (hydroxyaryl) cycloalkanes such as 1,1-bis (4-hydroxyphenyl) cyclohexane and 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 9,9-bis ( Fluorenes such as 4-hydroxyphenyl) fluorene and 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene; , 4'-dihydroxydiphenyl ether, dihydroxyaryl ethers such as 4,4'-dihydroxy-3,3-dimethylphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyl Dihydroxyaryl sulfides such as phenyl sulfide, hydroxyaryl sulfoxides such as 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-3-3′-dimethylphenyl sulfoxide, 4,4′-dihydroxydiphenyl sulfone, 4 , 4′-dihydroxy-3,3′-dimethylphenylsulfone and the like.

  These aromatic dihydroxy compounds can be used alone or in combination.

  It is also possible to use a polycarbonate in which a part of the aromatic dihydroxy compound is replaced with a terephthalic acid and / or isophthalic acid component. By using such a structural unit as a part of the structural component of the polycarbonate composed of bisphenol A, the properties of the polycarbonate, such as heat resistance and solubility, can be improved. The present invention can also be used for such a copolymer.

(Molecular weight of polycarbonate)
The molecular weight of the polycarbonate according to the present invention is not particularly limited, but the viscosity average molecular weight determined from viscosity measurement at 20 ° C. in a methylene chloride solution having a concentration of 5.0 g / l is preferably 30,000 to 200,000, preferably May be those in the range of 30,000 to 120,000.

When the viscosity average molecular weight is too small, it is not preferable because, when the film is punched out as a thin disk, a fine notch is formed in the punched end face or chips are easily generated. In addition, when the viscosity average molecular weight is too high, there is a problem that a flat liquid film is hardly formed when the solution is formed, and thickness unevenness (unevenness) of the film is deteriorated.
(Film production)
The plastic film of the present invention is preferably formed from a polycarbonate by a solution casting method. The reason why the solution casting method is preferred is that it is difficult to cause fine streak-like unevenness in the thickness of the plastic film or foreign matter.

(A: Solvent)
The solvent for polycarbonate that can be used when the plastic film according to the present invention is formed by casting is not particularly limited, and generally known solvents can be used. For example, examples of the solvent used for preparing the solvent for the aromatic polycarbonate include methylene chloride, 1,3-dioxolane, a mixture thereof, and a solvent mainly composed of these.

  These solvents preferably contain as little water as possible in the production of films. When methylene chloride is used as the solvent, the water content is 50 ppm or less, more preferably 30 ppm or less. This dehydration (drying) of the solvent can be carried out by a dehydration apparatus filled with a generally known molecular sieve.

(I: Solution casting)
A solution is prepared by dissolving the aromatic polycarbonate in the above solvent. This solution is usually adjusted so that the polycarbonate content is 15 to 35% by mass. The resin solution adjusted as described above is extruded by an extrusion die and cast onto a support.

(U: Dry)
The cast liquid film is partitioned into several compartments and dried using an oven that can change the drying conditions (hot air temperature, wind speed, etc.) of each compartment. In the present invention, the drying process is divided into five sections. In the first section, the liquid film immediately after casting on the support is dried so as not to cause so-called leveling unevenness so that the surface is not disturbed as much as possible. In order to increase the drying efficiency, the heating method includes a method of drying the cast liquid film with hot air or a method of heating the anti-liquid film surface of the belt with a heat medium. It is preferable to use hot air because of easy handling.

  The temperature of the belt surface immediately after casting and the temperature of the atmosphere should not be raised above the boiling point of the dissolving solvent of the polycarbonate. Raising the temperature of the liquid film above the boiling point results in the formation of bubbles in the film due to bumping of the solvent. When the solvent is methylene chloride, the temperature is 40 ° C. or lower, preferably 30 ° C. or lower.

  When the solvent is methylene chloride, the temperature is set to 45 to 50 ° C. in the next second section, and it is dried until the methylene chloride concentration in the liquid film is about 30 to 40% by mass so that the liquid film does not deform. It is good.

  When the solvent is methylene chloride, the temperature in the third section is 45 to 50 ° C., and the amount of solvent in the film is preferably about 23 to 27% by mass.

  In the fourth section, the drying temperature is preferably 50 to 55 ° C., and the amount of solvent in the film at this time is preferably about 18 to 20% by mass. In the fifth section, the film is preferably peeled off from the support after cooling to about 15 ° C.

(D: After drying)
Next, after the film is post-dried, the film is further dried for use as it is unstretched or for use after stretching. At this time, it is preferable to dry the film while controlling the optical properties (refractive index) of the film.

  This drying is performed by appropriately combining known drying methods such as a pin tenter that grips and conveys both ends in the width direction of the film, a roll suspension dryer, and an air floating dryer, and controls the optical characteristics of the film. be able to. The film thus obtained is wound up to obtain an aromatic polycarbonate film for optical use. The final film thickness is preferably 50 to 130 μm.

(O: Film winding process)
In the film winding process, a polyethylene terephthalate film is used as a surface protective film (also referred to as a protective film). The film end is pulled out from the roll, overlapped with the polycarbonate film and nipped by a nip roll, the air between the films is driven out, and both are wound together so as not to get wrinkled. Thus, the plastic film wound body according to the present invention is produced.

[Evaluation method for polycarbonate film substrate]
1) Method for measuring film thickness A sample for the entire width was collected at 1 m in the winding direction of a polycarbonate film on which no 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, that portion 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 a film.

2) Measurement method of film thickness unevenness In the measurement method using the micrometer of 1) above, there is a possibility of missing thickness unevenness other than the measurement point, for example, thin streaky thickness unevenness. Continuous measurement was performed using a film thickness tester KG601A manufactured by Co., Ltd. The measurement film was sampled as follows. That is, 10 samples for the entire width 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 film thickness tester and recorded on the recording paper. Thus, the difference (thickness range) between the maximum value and the minimum value of the recorded thickness was obtained for the ten films, and the film having the maximum thickness range was displayed as the thickness unevenness of the film.

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. Thus, a measurement sample having 15 points in the film winding direction and 15 points in a direction perpendicular to the film (width direction) was prepared. The measurement sample was suspended in a 140 ° C. constant temperature 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 at 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 performed 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 length of 40 mm in the winding direction was collected at three locations in the winding direction at intervals of 50 cm. Next, this strip-shaped film was cut at intervals of 40 mm to prepare a 40 mm square sample for measurement. That is, since there are 25 strips and 3 strip samples from 1000 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 instrument was used to measure the in-plane retardation Re value by making a light beam incident on the polycarbonate film surface in the vertical direction.

7) Measurement of retardation value (Rth value) in the thickness direction Sampling was performed in the same manner as the measurement in the above item 6), and measurement was performed with KOBRA-21ADH. The polycarbonate film sample was rotated about its slow axis or fast axis, the retardation was measured by changing the incident angle, and the 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 perpendicular 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 were as follows.
Stylus tip radius: 2μm
Measurement pressure: 30 mg (2.94 × 10 ⁻⁴ N)
Cut-off: 0.08mm
Measurement length: 1.0mm
In the same manner as the parent sample in 3) above, three points in the full width direction of the film were sampled 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.

[Surface protective film (protective film)]
(1) Surface protective film without adhesive In the present invention, a surface protective film is laminated on a plastic film so as to cover at least one surface of the plastic film. Lamination is performed by winding a plastic film and a protective film together. As the protective film to be wound together, a film made of polyethylene terephthalate to which no adhesiveness is imparted on both sides is used. As such a film, a biaxially stretched film can be preferably used. These biaxially stretched films are preferable since a film having small (good) thickness spots is obtained. The stretching ratio is preferably 3.0 times or more in both the vertical and horizontal directions, and more preferably 3.5 times or more in both the vertical and horizontal directions. Further, it is preferable that the Young's modulus in the vertical and horizontal directions is 450 kg / mm ² or more (4.41 GPa or more). In particular, those having a Young's modulus in the vertical and horizontal directions of 550 kg / mm ² or more (5.39 GPa or more) are suitable. In particular, a material having a Young's modulus in the vertical direction is higher than the Young's modulus in the horizontal direction.

  The thickness of these films is preferably 10 to 50 μm, and the surface roughness Ra is preferably 10 nm to 30 nm, and it is preferably substantially free of coarse surface protrusions, for example, 3 μm or higher.

(2) Surface protective film wound up with release paper or release film In the present invention, a release paper or release film is laminated on an adhesive layer, and a surface protective film with an adhesive layer used as a wound layer is used. it can. The wound layer body is a composite form of a base material layer, an adhesive layer, a release paper, or a release film.
The material of the base material layer is not particularly defined, but polyethylene and / or ethylene-α-olefin copolymer can be preferably used. In the case of using an ethylene-α-olefin copolymer, it is preferable that the amount of comonomer is small and the density is higher than that used for the pressure-sensitive adhesive layer. The blending of the ethylene-α-olefin copolymer is effective for improving fluidity during extrusion and adjusting the stiffness.

The material of the pressure-sensitive adhesive layer is not particularly specified. A widely used pressure-sensitive adhesive layer may be an ethylene-vinyl acetate copolymer, a base material layer may be polyethylene, and a co-extrusion may be used. It is also possible to use an adhesive containing an ethylene-α-olefin copolymer and having improved adhesive strength increase behavior due to heat. The polycarbonate film with a surface protective film using an adhesive that has improved the increase in adhesive strength due to heat like this does not increase the adhesive strength even if it is exposed to high temperatures in the drying process after applying the curable composition, and the wound layer body can be used as it is. It is very preferable because it can be configured and the surface protective film can be easily peeled off when necessary.
The surface protective film using the pressure-sensitive adhesive containing an ethylene-α-olefin copolymer is described in, for example, Japanese Patent Application Laid-Open No. 2001-40309 or Japanese Patent Application Laid-Open No. 2001-303005. A protective film can be preferably used.

  The release paper or release film is not particularly specified, but it is important that the transfer substance is not present on the surface not in contact with the pressure-sensitive adhesive layer. This is because even if a release paper or release film is used to prevent the transfer of the adhesive, if the release paper or release film has a transfer substance, the transfer substance causes unevenness. In particular, careful attention is required when a compound containing silicon element or fluorine element is used as a release agent in order to increase releasability.

  Although the thickness difference between the base material layer and the pressure-sensitive adhesive layer of the surface protective film for polycarbonate film of the present invention is not particularly limited, the thickness of the base material layer is usually 20 to 20 which is usually used for this kind of application. A thickness of 100 μm is preferable, and a thickness of 50 to 80 μm is particularly preferable. Similarly, the thickness of the pressure-sensitive adhesive layer is preferably 10 to 30 μm which is usually used for this kind of use.

[Hardened layer]
The cured layer of the present invention is formed by sending out a wound layer produced by winding up a surface protective film and polycarbonate, and applying, drying and curing the curable composition.
The curable composition may be a thermosetting composition or an active energy ray curable composition, but is preferably formed of an active energy ray curable composition from the viewpoint of productivity, and an ultraviolet curable composition. It is particularly preferable that it is formed by a product.
The film thickness of the functional layer is preferably 10 μm or less, particularly when the transparent plastic film substrate is a polycarbonate film. The polycarbonate film is soft (low rigidity), and the curl becomes strong when the thickness of the cured layer exceeds 10 μm.

[Thickness unevenness of cured layer]
In the present invention, it is necessary that the film thickness unevenness is not observed when an arbitrary 5 × 5 cm square sample is cut out from the long roll-shaped optical film. The film thickness unevenness of the cured layer can be evaluated as follows.
(1) When there is a difference in refractive index of 0.03 or more between the cured layer and the polycarbonate film substrate The film thickness unevenness can be accurately evaluated by using the interference of light between the substrate / cured layer interface and the cured layer interface. it can. As the light source, a monochromatic light source such as a mercury lamp or a sodium lamp or a three-wavelength fluorescent lamp having a high monochromatic light component ratio can be used. In the present invention, importance is attached to simplicity, and evaluation under a three-wavelength fluorescent lamp is adopted. The refractive index of the polycarbonate film is around 1.60, and the refractive index of the cured layer composed of a normal organic compound is around 1.50, so there is a refractive index difference of 0.10 or more. The evaluation method is effective.
Specifically, the substrate surface of an arbitrary sample cut out 5 × 5 cm from a long roll-shaped optical film is painted black, and when the cured layer is observed under a three-wavelength fluorescent lamp, a ring shape is formed by a dark color portion or a light color portion. In the case where no interference fringes are observed, the film thickness is not uneven.

(2) When refractive index difference between hardened layer and polycarbonate film substrate is less than 0.03 In this case, film thickness unevenness can be evaluated based on surface irregularities with respect to a reference plane using a Fizeau interferometer. As the Fizeau interferometer, a commercially available Fujinon laser interferometer F601 or the like can also be used.
Specifically, after the surface of the sample substrate on which the hardened layer is not laminated is treated with sandpaper, the interference formed in a ring shape by the dark color portion or the light color portion when observed with a laser interferometer F601 manufactured by Fujinon. If no stripes are observed, the film thickness is not uneven.

  As described above, the portion where the film thickness unevenness is evaluated is a product in the coating portion, and does not include a portion that is cut off and discarded later, such as a coating end portion.

[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, 1.0 to 4.0 μm is more preferable, and 2.5 to 4.0 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 the inorganic fine particles, the swelling of the transparent plastic film substrate by the 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.

  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-3-179010.

  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.

[Coating]
The cured layer of the present invention is prepared by dipping, spinner, spraying, roll coater method, gravure method, wire bar method, slot extrusion coater method (single layer, multilayer) on a polycarbonate film substrate. It can be prepared by coating by a known thin film forming method such as a slide coater method, drying, irradiating with ultraviolet rays 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, and scratches easily occur when rubbed with steel wool. 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.

[Adhesive layer]
When the optical hard coat film described above is used as a light-transmitting layer of an optical disc, it is preferably bonded to a substrate including a support and a recording layer via an adhesive layer. In the step of installing the adhesive layer, the adhesive layer can be continuously provided on a surface different from the hard coat layer coating surface of the translucent film in which the hard coat layer is formed on one surface in advance. As a method of providing the adhesive layer, a method of attaching a pre-formed adhesive layer (hereinafter referred to as an indirect method as appropriate), and directly applying an adhesive on the surface of the translucent film and drying it. A method of forming an adhesive layer (hereinafter, referred to as a direct method as appropriate) can be broadly classified.

  In the case of the indirect method, the “method for attaching a pre-formed adhesive layer” means, for example, applying a continuous adhesive to the surface of a release film having the same size as the translucent film and drying it. Then, a method is shown in which an adhesive layer is provided over the entire area of one surface of the release film, and the adhesive layer is attached to the translucent film. As a result, an adhesive layer with a release film is provided on the entire other surface of the translucent film.

  In the direct method, the front end of the translucent film wound in a roll shape is sent to a predetermined application region, and the adhesive is continuously applied from the front end to the end of one side of the translucent film, In this method, after the coating film is formed, the coating film is sequentially dried, and an adhesive layer is provided over the entire other surface of the translucent film.

In the indirect method and the direct method described above, conventionally known coating means can be used as the pressure-sensitive adhesive coating means. Specific examples include a spray method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method.
Moreover, as a drying means, conventionally well-known means, such as heat drying and ventilation drying, can be used.

  As the pressure-sensitive adhesive, acrylic-based, rubber-based, or silicon-based pressure-sensitive adhesives can be used, but acrylic-based pressure-sensitive adhesives are preferable from the viewpoints of transparency and durability. As such an acrylic pressure-sensitive adhesive, 2-ethylhexyl acrylate, n-butyl acrylate and the like are the main components, and in order to improve cohesion, short-chain alkyl acrylates and methacrylates such as methyl acrylate, ethyl acrylate, and methyl methacrylate are used. And acrylic acid, methacrylic acid, acrylamide derivatives, maleic acid, hydroxylethyl acrylate, glycidyl acrylate, and the like, which can be crosslinking points with the crosslinking agent, are preferably used. The glass transition temperature (Tg) and the crosslinking density can be changed by appropriately adjusting the mixing ratio and type of the main component, the short chain component, and the component for adding a crosslinking point.

  Examples of the crosslinking agent used in combination with the pressure-sensitive adhesive include an isocyanate crosslinking agent, an epoxy resin crosslinking agent, a melamine resin crosslinking agent, a urea resin crosslinking agent, and a chelate crosslinking agent. Among these, an isocyanate crosslinking agent is used. An agent is more preferable. Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, naphthylene-1,5-diisocyanate, o-toluidine isocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, and the like. Isocyanates, products of these isocyanates with polyalcohols, and polyisocyanates formed by condensation of isocyanates can be used. Commercially available products of these isocyanates include Nippon Polyurethane, Coronate L, Coronate HL, Coronate 2030, Coronate 2031, Millionate MR, Millionate HTL; Takenate D-102, Takenate D-110N from Takeda , Takenate D-200, Takenate D-202; manufactured by Sumitomo Bayer, Death Module L, Death Module IL, Death Module N, Death Module HL;

An adhesive layer is formed on the surface of the translucent film other than the hard coat layer, but it is wound up in a roll shape in the subsequent process to prevent the hard coat layer and the adhesive layer from sticking to each other. Therefore, it is preferable that a release film is attached to the surface of the adhesive layer. As described above, in the indirect method, a release film can be applied in advance. On the other hand, in the case of the direct method, it is preferable to newly add a step of attaching a release film to the surface of the adhesive layer after the adhesive layer is formed on the surface of the translucent film.
Here, examples of the release film attached to the surface of the adhesive layer include a polyethylene film, a polyethylene terephthalate film, a polyethylene naphthalate film, a polycarbonate film, and a triacetate cellulose film.

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

[Production 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 / Co-extruded high-density polyethylene of cm ³ from a flat die to produce a surface protective film consisting of a laminated film with a total thickness of 60 μm and a pressure-sensitive adhesive layer thickness of 15 μm. The pressure-sensitive adhesive layer and the polyethylene film are alternately laminated. I wound it up like
(Preparation of surface protective film (p-2))
The winding method was changed with respect to the surface protective film (p-1), and a PET film having a thickness of 30 μm and a surface roughness of 20 nm was wound as a release film while being bonded to the pressure-sensitive adhesive layer.
(Preparation of surface protective film (p-3))
Co-extrusion of ethylene, polyvinyl acetate copolymer and high density polyethylene having a density of 0.940 g / cm ³ from a flat die to produce a surface protective film having a total thickness of 60 μm and a pressure-sensitive adhesive layer thickness of 15 μm, It wound up so that an adhesive layer and a polyethylene film might be laminated | stacked alternately.
(Preparation of surface protective film (p-4))
The winding method was changed with respect to the surface protective film (p-3), and the PET film having a thickness of 30 μm and a surface roughness of 20 nm was wound as a release film while being bonded to the pressure-sensitive adhesive layer.

[Production of long roll polycarbonate film with surface protective film]
(Preparation of long roll-shaped polycarbonate film (s-0) 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 then cast onto the 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.
(First section) At the initial stage of drying, be careful not to cause a deformation (leveling failure) of the polycarbonate film by heating it by blowing hot air of 30 ° C on the back of the support and setting the atmospheric temperature of the polycarbonate film to 20 ° C. And dried.
(Second section) Next, the atmosphere temperature was set to 45 ° C. by blowing hot air, and the methylene chloride concentration in the polycarbonate film was dried to about 35% by mass.
(Third section) Next, by blowing hot air, the atmosphere temperature was dried at 50 ° C., and the amount of solvent in the polycarbonate film was 25% by mass.
(Fourth section) In this section, drying was performed at an atmospheric temperature of 55 ° C. The amount of solvent in the polycarbonate film at this time was 20% by mass.
(Fifth section) In this section, the polycarbonate film was cooled together with the support in an atmosphere of 15 ° C. The amount of solvent in the polycarbonate film at the end of this step was 18% by mass.

  Next, the polycarbonate film peeled off from the support was further fed into a pin tenter type dryer and conveyed while drying.

  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, drying of the polycarbonate film progressed from the inlet and the width shrunk accordingly. Therefore, the pin tenter was also dried so that the rail width of the pin tenter was narrowed 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 promote the drying of the polycarbonate film. At this time, the rail width of the pin tenter was set so as not to cause molecular orientation of the polycarbonate film as much as possible. The first half of the hot air temperature was 90 ° C., 110 ° C., 120 ° C., and the middle 4, 5 zone temperature was 130 ° C., and the polycarbonate film was cut off from the pin piercing portion at the 5 zone portion. Further, the hot air temperature was 135 ° C. in 6 zones.

  At the outlet of the pin tenter, the polycarbonate film was pulled at a pulling tension of 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.

  Thus, the properties of the obtained polycarbonate film 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. The rate of thermal dimensional change is 0.07%, the total light transmittance is 90%, the amount of solvent contained is 0.3% by mass, the in-plane retardation value is 4 to 8 nm, the surface roughness Ra is 1.8 nm, and the Rth value is The maximum value was 90 nm.

  Further, the obtained polycarbonate film was rolled up with a winder and a 20 μm-thick polyethylene terephthalate film (Young's modulus, 5.29 GPa in both length and width, and surface roughness Ra on both sides 25 nm) was layered and laminated as a surface protective film. A long roll polycarbonate film (s-0) with a surface protective film of 500 m was prepared.

(Production of long roll polycarbonate film (s-1) with surface protective film)
The surface protective film is changed to (p-1) with respect to (s-1), the adhesive surface is superimposed on the polycarbonate film, niped and laminated, and a 500 m long roll-shaped polycarbonate film with a surface protective film (s- 1) was created.

(Preparation of long roll polycarbonate film (s-2) to (s-4) with surface protective film)
The surface protective film was changed as shown in Table 1 with respect to (s-1) to prepare long roll polycarbonate films (s-2) to (s-4) with a surface protective film.

[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. After adding 12.0 parts by mass of a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) to the resulting solution and stirring until dissolved, 380 parts by mass of IPA-ST (average particle size of 10 to 20 nm, solid content) 30 mass% SiO ₂ sol isopropyl alcohol dispersion (manufactured by Nissan Chemical Co., Ltd.) and 257 mass parts MIBK-ST (average particle size 10-20 nm, solid content concentration 30 mass% SiO ₂ sol methyl isobutyl) Ketone dispersion (manufactured by Nissan Chemical Co., Ltd.) was added and stirred to obtain a mixture, which was filtered through a polypropylene filter (PPE-03) having a pore size of 3 μm to prepare a hard coat layer coating solution (h-1). did.

(Preparation of hard coat film)
Example 1
After setting the coating speed to 10 m / min, sending out a long roll film (s-0) with a surface protective film having a width of 1000 mm while winding the surface protective film, and drying the hard coat coating solution (h-1) The coating was applied using a bar coater so that the thickness of the coating became 3.3 μmm and the coating width was 980 mm, dried at 70 ° C. for 1 minute, and then air-cooled at 160 W / cm under a nitrogen purge (oxygen concentration 0.1%). Using a metal halide lamp (manufactured by Eye Graphics Co., Ltd.), ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 500 mJ / cm ² were irradiated to cure the hard coat layer, and the hard coat film was wound up to 300 m.
The refractive index of the cured layer was 1.48, and the surface roughness Ra of the substrate surface on which the cured layer was not laminated was 1.8 nm.

Examples 2-5, Comparative Examples 1-4
With respect to Example 1, the base material was changed as shown in Table 2, and Example Samples 2 to 5 and Comparative Example Samples 1 to 4 were produced. In Examples 3 and 5 and Comparative Examples 2 and 4, a hard coat layer was laminated and wound with the surface protective film attached to the substrate. Other than that, immediately after sending out the substrate, the surface protective film was peeled off, a hard coat layer was laminated, and wound up.

Example 6
The coating speed is set to 10 m / min, a long roll film (s-3) with a surface protective film having a width of 1000 mm is sent out while winding the surface protective film, and isopropyl alcohol is applied at 10 cml / m ² using a bar coater. And dried at 50 ° C. for 30 seconds. Subsequently, the hard coat coating solution (h-1) was applied using a bar coater so that the thickness after drying was 3.3 μm and the coating width was 980 mm, dried at 70 ° C. for 1 minute, and then purged with nitrogen. Using an air-cooled metal halide lamp (produced by Eye Graphics Co., Ltd.) at 160 W / cm at the bottom (oxygen concentration 0.1%), irradiating ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 500 mJ / cm ² , hard coat The layer was cured and the hard coat film was wound up to 300 m.

Example 7
The long roll film (s-3) with a surface protective film was removed from Example 6 without removing the surface protective film, and the cured film was laminated with the surface protective film attached.

  The refractive indexes of the cured layers of Example Samples 2 to 7 and Comparative Example Samples 1 to 4 were all 1.48. Moreover, surface roughness Ra of the base-material surface which has not laminated | stacked the cured layer after peeling a surface protective film was 1.8 nm.

(Evaluation of hard coat film)
(1) Measurement of thickness non-uniformity of hard coat layer Both ends of the finished long roll-shaped hard coat film are spaced 5 cm apart, 5 × 5 cm square sample, 5 cm square sample 5 × 5 cm square sample, ...... Repeat 10 samples of 5 x 5 cm square, rubbing the back with sandpaper, applying black magic so that reflection on the back does not occur, put on a desk, and 3 wavelengths from 30 cm above The sample was illuminated with a fluorescent lamp (National Paroch fluorescent lamp FL20SS · EX-D / 18), and interference fringes were observed.
Three-level evaluation was performed according to the following criteria.
Ring-shaped interference fringes are not observed: ○ Ring-shaped pitches with interference pitch larger than 5 mm are observed: Δ
Interference fringes with a ring pitch of 5 mm or less are observed: ×
(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.

From the results shown in Table 1, the following is clear.
A film using a surface protective film that does not use an adhesive had no film thickness unevenness. (Example 1)
What used the surface protection film with an adhesive which prevented the transfer of the adhesive and wound up using the release film did not have a film thickness nonuniformity in both types of adhesives. (Examples 2 to 5)
The film obtained by washing and removing the pressure-sensitive adhesive transferred from the surface protective film with pressure-sensitive adhesive had no film thickness unevenness. (Examples 6 to 7)
Film thickness unevenness was observed for both types of adhesives using a surface protective film with an adhesive wound up without using a release film. (Comparative Examples 1-4)

[Application to optical disc]
(Production of optical disc)
Example 1 described in paragraphs [0122] to [0123] of Japanese Patent Application Laid-Open No. 2003-267397 is referred to as Comparative Example 20 of the present invention, and the cover film described in [0124] (polycarbonate film, Teijin Pure Ace, Thickness: 80 μm, with a second release film on one side; surface roughness of surface D of the second release film, 250 nm), instead of the length of Example 1 and Comparative Example 1 shown above An optical recording medium (optical disk) was obtained using a long roll hard coat film. (Example 21 and Comparative Example 21)

[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) 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 is again rolled. Winding process]
First, an adhesive layer having a thickness of 17 μm was provided on the surface of the hard coat film using the adhesive layer installation 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 region (drying process) to obtain a release film provided with the pressure-sensitive adhesive layer. And the release film provided with the adhesion layer is further conveyed, and the surface of the cover film (long roll-like hard coat film of Example 1: 83 μm, with a single-sided release film) fed from the roll 4 with the roll 6 is used. The protective film was wound up while being peeled off, and bonded in the bonding region 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 and hard coat film provided with the adhesion layer (winding process).

[(C) Step of holding until the crosslinking reaction of the adhesive layer is substantially completed]
Thereafter, the roll 5 in the state of being co-wound with the release film including the adhesive layer and the cover film was held for 72 hours in an atmosphere of 23 ° C. and 50% Rh. This “72 hours” means that, in the above atmosphere, the adhesive layer in this example was measured over time with an infrared spectral absorption spectrum, 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) Step of punching the cover film provided with the adhesive layer into a disc shape, and (e) Step of stacking and holding the cover film provided with the disc-like adhesive layer substantially horizontally]
A release film and a cover film provided with a co-rolled adhesive layer were fed out from the roll 5 and punched into the same shape as the substrate. As shown in FIG. 2, the laminated body of the release film and the cover film having the punched adhesive layer is laminated approximately 50 horizontally so as to be fitted into a stock jig having an outer diameter slightly smaller than the center hole. did. This state was maintained for 1 hour.

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

[Comparative Example 21]
The long roll-shaped hard coat film of Example 21 was changed to Comparative Example 1 to obtain a Comparative Example 21 sample.

(Sample evaluation)
1. Evaluation of Noise Paragraph [0055] <Evaluation> of Japanese Patent Application Laid-Open No. 2003-267397 (1) When Example 21 and Comparative Example 21 were evaluated according to C / N (carrier-to-noise ratio), thickness unevenness was detected as noise. It was found that noise can be greatly reduced by the present invention.
<Evaluation> C / N (carrier-to-noise ratio)
Using the recording / reproduction evaluation machine (manufactured by Pulstec Corp .: DDU1000) equipped with a 405 nm laser and NA: 0.85 pickup, the manufactured optical disk was simply processed under conditions of a clock frequency of 66 MHz / linear speed of 5.6 m / s. Recording / reproduction with a signal of one frequency (2T = 0.13 μm) and measurement of C / N using a spectrum analyzer gave the following results.
Example 21: 52 dB
Example 23: 51 dB
Comparative Example 21: 33 dB
2. Scratch resistance Evaluation to the extent that scratches are visible when rubbing the surface of the light-transmitting layer side of the sample using # 0000 steel wool while applying a load of 1.96 N / cm ² (○ is 100 times) Evaluation was made in a state where no trace was seen even after rubbing, and a mark x was visible in less than 30 times), and the following results were obtained.
Example 21: ○ Comparative Example 20: ×
Comparative Example 21: Yes

  From the above results, the hard coat film of the present invention is suitable as a cover layer of an optical disk because it is resistant to scratches and noise is greatly reduced.

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

Claims (6)

  A long roll-shaped optical film in which a cured layer is laminated on a substrate made of a polycarbonate film, wherein interference fringes due to film thickness unevenness of the cured layer are not observed the film.   A long roll-shaped optical film in which a cured layer is laminated on a substrate made of a polycarbonate film, and when the above-mentioned long roll-shaped optical film is produced using a polycarbonate film wound layer with a surface protective film The long roll-shaped optical film produced so that the adhesive of the said surface protection film may not adhere to the surface which should apply | coat the said hardened layer of the said polycarbonate film.   The long roll optical film according to any one of claims 1 to 2, wherein the polycarbonate film substrate is produced by a casting method.   The long roll-shaped optical film according to claim 1, wherein the cured layer has a thickness of 1 to 10 μm.   The long-roll optical hard coat film according to any one of claims 1 to 4, wherein the hardened layer is a hard coat layer having scratch resistance against steel wool. An optical disk on which an optical hard coat film obtained from the long roll-shaped optical hard coat film according to claim 5 is mounted as a cover layer.

Images