TW200912921A - Laminated film for optical member - Google Patents

Abstract

The purpose of the present invention provides a laminated film which has small birefringence, excellent surface smoothness and has substrate representing excellent optical anisotropic. The present invention relates to a laminated film for optical member that is form by laminating a protective film which the lamination thickness is 10 to 100 μ m, the width uniform is less than ± 1.5 μ m on the substrate film, wherein the said substrate is form by a thermoplastic resin which has 10 to 150 μ m thickness, the thickness uniform is less than ± 2 μ m, the average of in-plane birefringence (Δ n) is 0.00001 to 0.00017, the average of thickness birefringence (Δ nth) is 0.00001 to 0.001.

Description

The invention relates to a laminated film for an optical member which is used as a component of an optical member such as a high-density optical disk, a liquid crystal display, an organic EL display, an electronic paper, or the like. A base film and a film that protects the base film. Further, there is a film roll obtained by winding the laminated film and a film obtained by using the laminated film for the optical member. [Prior Art] In order to record and reproduce text information, video information, and sound information in large quantities, optical information recording media (CDs) such as compact discs (CDs) and digital versatile discs (Digital Versatile Discs (DVDs) are required to be higher. Recording density. In particular, since the blue-violet laser was developed, an optical disc system using the blue-violet laser and the numerical aperture (NA) read/write head has been developed in order to play a recorded image of a digital high-definition TV. For example, in Patent Document 1 and Non-Patent Document 1, the proposal discloses a disc technology in which a film surface is incident on one side for reading information. Moreover, currently available high-density optical disc systems have Blu-r ay Discs. The Blu-ray disc is characterized in that a reflective film or a recording film having a concave-convex pattern such as a pit or a groove is provided as an information recording layer on a disc substrate having a thickness of 1.1 mm, and a thickness of 0.1 mm called a cover layer is provided thereon. Light transmissive layer. The reading and writing of information is performed using blue-violet laser light from the side of the light transmitting layer. The light transmitting layer is formed by adhering a plastic film composed of a polycarbon 200912921 acid ester or the like to an information recording layer via an adhesive or the like. In order to prevent reading or writing of information, the plastic film is required to have high directivity such as small birefringence and good flat sliding property. Moreover, since the Blu-ray disc is high in density and large in capacity, the light transmitting layer is slightly damaged and foreign matter adheres, which may cause information to be unreadable and writable. Therefore, when used as a bare disk protected as an unused cassette or the like, a hard coat layer is provided to protect the light transmitting layer. In the production of the optical disk, it is preferable to bond the plastic film of the light transmitting layer to the optical disk while pulling the plastic film from the wound film roll. However, a plastic film which is generally required to have a very flat surface is inferior in slipperiness, and usually it cannot be wound up in a roll shape to form a uniform film roll. Therefore, in order to obtain a film roll for optical use, a protective film having an adhesive property is laminated on a plastic film to be wound. That is, a very flat plastic film for optical use (referred to as a base film in the present invention) is laminated with an adhesive protective film, and while protecting the surface thereof, the opposite side of the protective film is It is suitably roughened to have a slippery structure, and the laminated film can be wound into a roll shape. Usually, a laminated film is pulled out from the film roll, and after the protective film is peeled off, the base film is punched into a disk shape, and bonded to the formed optical disk substrate to produce a Blu-ray disc. However, in this method, irregularities are generated in the base film, and this unevenness is one of the causes of an increase in the electric signal fluctuation of the optical disk. Since such a disc having an increased electric signal has a possibility of hindering the recording and reproduction of information, the inspection at the time of manufacture is judged to be unacceptable and discarded. Therefore, the production of a laminated film using an optical member having a large number of irregularities is economical, and therefore, it is required to disclose a weak adhesion (2). However, the film is not viscous. : Protective film, the second method (patent protection film can be used to protect the soluble unevenness of the coating, dry disc Oplus E, 200912921 disc, will produce a large number of discarded discs, not only from the effective use of resources In addition, there is a negative effect on the laminated film of the optical member having a small surface unevenness and high productivity. Therefore, in order to improve the surface unevenness, there is a proposal to use a base film and a protective film without using an adhesive therebetween. And a method of laminating and winding to improve the unevenness (the patent is a method of, for example, manufacturing a base laminated protective film having a width of 1,0 0 mm and winding the obtained roll, and unwinding the roll width from the roll In the case of a 140 mm laminated film, scratches due to friction of the substrate film may occur due to the thinness of the protective film. It is proposed to disclose a method in which a substrate film and a weakly adhesive adhesive are used therebetween. Co-wound and two documents 3). However, the method must have an adhesive film which is uniformly coated and has strong adhesion and weak adhesion to the substrate film. Further, there is also a proposal to disclose a method of reducing the base film method by applying a solvent of a resin of a base film and drying it (Patent Document 4). However, there must be a step before the use of the film. (Patent Document 1) Japanese Patent Laid-Open No. Hei 08-23-23 No. 5 (Non-Patent Document 1) A large-capacity light of 12 Gbytes, Volume 20, Issue 2, page 183 (February 1998) [2] Japanese Patent Laid-Open Publication No. JP-A No. 2001-221 (Patent Document 3) International Publication No. 2/3/0427 No. 200912921 (Patent Document 4) Special Opening 2 0 0 7 - 0 1 6 0 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The object of the present invention is to provide a laminated film comprising a base film having a small birefringence, a good flat sliding property, and excellent optical isotropic properties. The object of the present invention is to provide a laminated film which is excellent in slidability. Further, an object of the present invention is to provide a laminated film which, when used as a component of a compact disc or the like, has a low rate of occurrence of defective products when producing a compact disc. The object of the present invention is to provide a Further, the object of the present invention is to provide an optical disk having excellent electrical signal characteristics such as shaking and error rate. Moreover, the object of the present invention is to provide a laminated film. In the case of peeling off the protective film, it is possible to obtain a film having excellent surface flat slidability. The inventors of the present invention have focused on the production of a laminate film which can be used as an optical member and has no fine unevenness. A method of using a film, and found that a base film having a small thickness unevenness and a good flat sliding property and a protective film having a small thickness unevenness are used, and by laminating the base film and the protective film The tension to be received is within a predetermined range, and the unevenness of the protective film can be prevented from being transferred to the base film, and the present invention has been completed. That is, the present invention is a film which is a laminated film for an optical member in which a protective film is laminated on a base film, and the base film is composed of a polycarbonate resin and satisfies (1) a thickness of 1 〇 to 150 μm. (ii) the thickness is not ±2 μm or less, 200912921 (iii) The average 値 of the birefringence (Δ η) in the plane is 0.00001 to 0.00017, and (iv) the average of the birefringence (Δ nth) in the thickness direction値 is 〇〇〇〇〇1 to 0.001, and the protective film satisfies (i) a thickness of 10 to 100 μm, and (ii) a thickness of not more than ±1.5 μm. The present invention includes an laminated film for an optical member obtained by winding the laminated film. Moreover, the present invention includes an optical disk obtained by bonding a base film obtained by peeling a protective film from the laminated film to a substrate as a light transmitting layer. Further, the present invention relates to a method for producing a laminated film of an optical member comprising a laminated base film and a protective film, which is composed of a polycarbonate resin and which satisfies (0 thickness is 10 to 1 50 μm, (ii) not more than ±2 μm in thickness, (iii) the average 値 of the birefringence (Δ n) in the plane is o.ooooi~ 0.00017, (iv) birefringence in the thickness direction The average enthalpy of (Δnth) is o.ooooi~0.001, and the protective film satisfies (i) a thickness of 10 to 100 μm, (ii) a thickness of not more than ±1.5 μm, and the use of a laminate system satisfies the following formula ( 1) The condition of ~(3) is performed, (1) 1 0<Tb<200 200912921 1 0<Τρ< 1 5 0 (2) 1 ^ ΤΒ/Τρ ^ 1 0 (3) (wherein, ΤΒ indicates the layering The tension (N/m) per unit width of the base film, Τρ indicates the tension (N/m) per unit width of the protective film when laminated. [Embodiment] Hereinafter, the present invention will be described in detail. The present invention relates to a laminated film for an optical member in which a protective film is laminated on a base film, and the following is used in the present specification. The term "substrate film" means a film which is optically uniform and can be used for an optical member. "Protective film" means a film which is laminated on a substrate film and used. While suppressing the surface flaw of the protective base film, the roll formation of the so-called film roll can be favorably maintained in the production of the wound film roll. The "disc" means mainly by using a polycarbonate resin. The formed disk-shaped memory medium is provided to the information recording layer. The "light-transmitting layer" refers to a recording information layer that covers the optical disk with a transparent material to protect the information recording layer, and at the same time, irradiates the laser light through the transparent material to have a recording and reproduction. (Substrate film) The base film refers to a film which can be used as an optical member such as a high-density optical disk, a liquid crystal display, an organic EL display, or an electronic paper, because these products are used by -10 - 200912921 Polarization to reveal the function, in order to improve the performance of the product, it is required to use optical properties in a manner that does not affect the transmitted polarized light. The film, especially in the case of a disc, because the laser light is a short-wavelength blue-violet laser, the recording density becomes high, and the optical film which is used as the light-transmitting layer of the optical disc is required to have high optical uniformity. (Polycarbonate resin) The base film of the invention is composed of a polycarbonate resin. The optical disk substrate is usually made of a polycarbonate resin, and in consideration of the characteristics of the obtained optical disk, the quality of the laminated film for the optical member is required to match the physical properties. The optical disk substrate is preferable. The polycarbonate resin can be obtained by reacting a dihydroxy component with a carbonate precursor by an interfacial polymerization method or a melt polymerization method. Representative examples of the dihydroxy component include 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A) and 2,2-bis{(4-hydroxy-3-methyl)phenyl}propane. 2,2_bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)-3-methylbutane, 2,2-bis(4-hydroxyphenyl)-3, 3-dimethylbutane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 1,1-bis(4-phenyl)-cyclohexane' 1,1·double (4-hydroxyphenyl)_3,3,5-trimethylcyclohexane, 9,9-bis{(4-hydroxy-3-methyl)phenyl}anthracene and α,α bis(4-hydroxybenzene) Base)·diisopropylbenzene and the like. These dihydric phenols may be used alone or in combination of two or more. Among them, a polycarbonate resin obtained from a dihydroxy component having at least 50 mol% or more of bisphenol a is preferred. The content of biguanide A in the dihydroxy component is preferably at least 60 mol%, and is at least 75 mol. /. For better, at least 90% by mole is particularly good. Carbonate precursors may be carbonium halides, carbonates or haloformates, and -11-200912921 may be exemplified by phosgene, diphenyl carbonate or dihydric phenol. Interfacial polymerization or melt polymerization is used. When a polycarbonate resin is produced by a binary reaction, it may be an antioxidant or a dihydric phenol antioxidant. Further, the polycarbonate polymerizes a trifunctional or higher polyfunctional aromatic compound, and the acid ester resin may be a polyester carbonate resin obtained by copolymerizing an aromatic or aliphatic acid, or may be obtained. a mixture of polycarbonate resins. The polycarbonate resin has a molecular weight viscosity average molecular weight of 10,000 to 40,000, preferably 11,000 to 30,000 for a grinding of ~19,000. Since the viscosity average molecular weight of the optical disk substrate is a polycarbonate resin and the polycarbonate is used as the light transmitting layer, the obtained film is less likely to become brittle, and it is possible to reduce the occurrence of a chipping at the end surface. In addition, in the case where the foreign matter is melt-squeezed and the thickness unevenness is unlikely to occur, the material is wound in a shape, and when the wound material is unwound, even when the punching property is conveyed, the flatness is good and the film is bonded. It is better to use the recording layer time barrier. The viscosity average molecular weight of the polycarbonate resin is preferably 1,7,500. Further, the polycarbonate resin is preferably a foreign matter or a thermally deteriorated substance which is extremely strong in amount. The viscosity average molecular weight (M) is obtained by obtaining a haloformate or the like from a solution of 100 ml of a solution of 7 g of a polycarbonate resin. Phenol and carbonate should be terminated with a terminal-stop resin. It can be a co-formed branched poly-carbon difunctional carboxylic acid. Two or more kinds of scales are used from time to time, and δ is good, and an ester film of about 1,2,0 0 0 5,000 is used. It is not easy to produce when it is cut into a dish or the like. Further, it is obtained by winding into a disk shape and mechanically not easily generating the bacteria at a specific viscosity (SP) 200912921 which does not contain high-molecular-weight methyl chloride at 20 °C.

V sp/c = [ V ] + 0.45 X [ 7? ] 2C

[η ]-1.23x10'4M0·83 (where c = 0.7, [7?] is an intrinsic viscosity) Further, the light transmitting layer is used in the same characteristics as those of the optical disk substrate (that is, the same raw material and has a similar viscosity) A film composed of a polycarbonate resin having an average molecular weight is preferred. The quality of the laminated film for an optical member is preferably such that the physical properties of the optical disk substrate and the physical properties of the light transmitting layer are made uniform. The physical properties include thermal expansion coefficient, moisture absorption expansion ratio, thermal shrinkage ratio, and viscoelastic behavior. When the optical disk substrate and the light transmitting layer are different in thermal expansion or heat absorption, thermal expansion and contraction characteristics, or when the viscoelastic behavior of the optical substrate is different, the optical disk after the optical disk substrate and the light transmitting layer having the information recording layer are attached to each other for durability. Sexual promotion tests or long-term changes in time may cause awkwardness due to unequal deformation. (Thickness) The thickness of the substrate film is 10 to 15 μm. The thickness of the film varies depending on the design of the film using the article as an optical member, and it is not always difficult to say that when the thickness is too thin, the handleability is poor, and when the thickness is too high, the transmittance is deteriorated. It may be unsatisfactory that the required characteristics of the optical member cannot be satisfied. In particular, when the light transmitting layer is used as a high-density optical disk, the thickness is preferably in the range of 50 to 100 μm. (Thickness in thickness) The thickness of the base film is not more than ± 2 μm, more preferably ± ΐ · 5 μm or less, and more preferably ± 1 μm or less. Because the thickness is not too large, the light is lifted. 200912921 Unevenness is not good. In particular, when a light transmitting layer as a high-density optical disk is used, it is not preferable because the thickness variation is large and the signal level fluctuation of the optical disk becomes large. (Total Light Transmittance) The total light transmittance of the base film is preferably 85% or more, more preferably 89% or more, and still more preferably 90% or more. In particular, when a light transmitting layer as a high-density optical disk is used, in order to prevent deterioration of the optical signal, the total light transmittance is preferably higher. (Average 双 of the birefringence (Δ η) in the plane) The average 値 of the birefringence (Δ η) in the plane of the base film is 0.00001 to 0.00017. The lower limit of the average 値 of Δη is preferably 0.00003, more preferably 0.00005. Further, the upper limit of the average 値 of Δη is preferably 0.00012, more preferably 0.00009. Δη is such that when the refractive index in the optical slow axis direction in the plane of the film is nx and the refractive index in the direction perpendicular thereto is ny, the enthalpy which can be obtained from Δ | nx-ny | is in the plane of the film. The size of the birefringence. When Δn becomes large When the light level is used as the light transmission layer, the signal level fluctuation is increased, which is not preferable. Further, the unevenness of the birefringence in the plane is preferably ±0.00005 or less, more preferably 0.00003 or less. (Average 双 of the birefringence (Δ nth) in the thickness direction) The average 値 of the birefringence (Δ nth) in the thickness direction of the base film is 0.0 000 1 〇 〇〇 〇〇 1 . The lower limit of the average 値 of Δ nth is 〇 〇〇〇〇 3, preferably 0.00005. Further, the upper limit of the average 値 nth is 〇 〇〇〇 6, preferably 0.0004. Δnth is such that when the refractive index in the direction of the optical slow axis in the plane of the film is ΠΧ ', when the refractive index in the direction perpendicular to the film is ny, the refractive index of the film in the thickness direction of the peak is nz - 200912921. The enthalpy obtained by ntfl (nx + xy)/2-nz| indicates the magnitude of the birefringence in the thickness direction of the film. As described in Patent Document 1 and Non-Patent Documents 1 to 2, the high-density optical disk system uses a large number of apertures of the objective lens for a head. Therefore, when compared with a conventional optical disc such as a CD or a DVD, the oblique incident angle of the laser light is large, and the influence of the thickness direction of the optical disc is increased. Therefore, when Δη^ is large, the signal level fluctuation of the optical disc becomes large, which is not preferable. Further, the unevenness of the birefringence in the thickness direction is preferably ± 〇 · 〇 〇 〇 〇 5 or less, and more preferably ± 0 · 0 0 0 0 3 or less. The thickness, thickness unevenness, total light transmittance, average 値 of Δη, and average enthalpy of Δnth of the films can be measured by the methods described in the examples. Further, when the size of the sample did not satisfy the conditions described in the examples, the sample size of the examples was assigned and measured. (Production of Substrate Film) A well-known film formation method such as a solution casting method, a melt extrusion method, or a calendering method can be used for the film formation of the base film. The base film is preferably a base film formed by a melt extrusion method. The solvent used in the solution casting method for extruding a solution from a die is, for example, an organic solvent such as dichloromethane, chloroform, dioxolane, toluene, dimethylformamide or N-methylpyrrolidone. It is better. The solution concentration is 1% by weight or more, preferably 15% by weight or more. In contrast, since the melt extrusion method does not use a solvent, productivity is excellent. The polycarbonate resin used in the base film of the present invention is excellent in moldability, and a film having uniformity of charge can be obtained even by a melt extrusion method, and a melt extrusion method is preferred. In order to obtain a uniform film, the melt extruder can use a melt extruder without a venting method. Further, a melt extruder having a vent hole can be used to deaerate the moisture in the raw material or the volatile gas generated from the melt-kneaded resin. In order to efficiently discharge the generated moisture or volatile gas to the outside of the melting extruder, it is preferred to provide a vacuum pump in the vent hole. Further, a mesh screen may be provided in a region in front of the head of the melt kneader to remove foreign matter or the like mixed in the extruded raw material, and foreign matter can be removed. Examples of such a mesh screen include a metal mesh, a mesh screen switcher, a sintered metal plate (a disk filter, etc.). (die) The die used in the melt extrusion method can use a T-shaped die (a hanger-type die) that supplies a resin from a central portion in the width direction of the die, and a resin from one end portion in the width direction of the die. Inflow of the type I die, etc. The chill roll may be either cooled by only one roll or cooled by a plurality of rolls, and it is preferred to uniformly and precisely control the surface temperature of the roll in order to uniformly cool the film. When cooling is performed using a plurality of rolls, there is a method of flowing a molten resin between a cooling roll (referred to as a first cooling roll) in which the molten resin is first contacted and a cooling roll (referred to as a second cooling roll) which is in contact with the second; The method of inflowing on the opposite side of the first cooling roll from the second cooling roll is exemplified below. (Resin temperature) The resin temperature at the time of melt extrusion is in the range of 50 to 600 Pa·s, and the range of 70 to 300 Pa·s in the range of 50 to 600 Pa·s at the shear rate of 100 (Ws). The temperature is better. By setting the cylinder of the extruder and the temperature of the -16-200912921 die, it is in this temperature range because the molten resin shows proper fluidity and can cut the inside of the extruder, the die and the lip of the die. The stress suppression is small and the birefringence can be reduced. At the same time, it is less likely to cause drift and retention in the cylinder of the extruder and the filter, and also has an effect of suppressing generation of thermally deteriorated foreign matter such as gel. (distance between the tip end of the lip and the cooling roll) At the time of melt extrusion, when the molten resin extruded from the die is cooled to a film state, the front end of the lip and the cooling roll (especially the cooling roll initially contacted by the molten resin) Between the contraction, or the turbulence of the ambient air, it is easy to produce uneven thickness or die stripe. Therefore, by sufficiently narrowing the gap between the front end of the lip and the cooling roll, the molten resin is prevented from being shaken in space, and a film in which thickness unevenness is suppressed can be obtained. Further, it is preferable that the distance between the front end of the lip and the cooling roller (L1 in Fig. 2) is 5 to 70 mm, preferably 5 to 50 mm, and more preferably 5 to 30 mm. Further, the molten resin discharged from the die is subjected to a tension in the flow direction when flowing down between the cooling rolls and the lips. On the other hand, heat shrinkage occurs upon contact with the chill roll and is cooled, but because of rapid solidification, shrinkage is restricted and tension is generated in the width direction. Since the film is birefringent by the orthogonal tension, the birefringence can be lowered by adjusting the falling position of the cooling roll of the molten resin, the cooling roll temperature, and the like and taking the tension balance. From the viewpoint of controlling the thickness unevenness, the interval between the front end of the lip and the cooling roll is preferably in the range of 5 to 70 mm as described above. (Distance between the front end of the lip and the horizontal direction of the cooling roller) 200912921 Further, the distance between the tip end of the lip and the horizontal direction of the cooling roller (L2 in Fig. 2) is viewed from a position where the rotation of the cooling roller can be seen to rotate clockwise. The front end of the lip is preferably from the center of the cooling roll to the right end of the cooling roll. This position varies depending on the size of the cooling roll and other film forming conditions. When the birefringence of the obtained film is large in the width direction of the film, the position can be adjusted to change the position of the front end of the lip to the right side. By increasing the tension in the flow direction of the film, the birefringence of the obtained film can be lowered. (temperature of the cooling roll) The temperature at which the molten resin extruded from the die is cooled to a film state and the temperature of the contact cooling roll is (Tg-45) to (Tg) with respect to the glass transition temperature (Tg) of the resin to be used. -l) The range of °C is preferably in the range of (Tg - 35) to (Tg - 1) °C. It is preferable to suppress the strain due to cooling so that the temperature of the cooling roll is in the above range. Thereby, the birefringence due to the cooling strain can be reduced. (Opening degree of the lip) Further, the opening degree of the lip is preferably 5 t to 25 t (micrometer) with respect to the thickness t (micrometer) of the film. Specifically, when a film having a thickness of 1 μm is extruded to form a film, it is preferred that the lip is about 0.5 to 2 · 5 mm. By adjusting the lip to this range, it is possible to reduce the shear stress of the discharged resin on the lip, and it is preferable to suppress the birefringence of the obtained film to be small. Further, in this range, since it is sufficiently wide with respect to the thickness of the film, it also has an effect of alleviating the pattern streaks caused by the contact of the film with the lip or the adhesion of the lip. (Additive) -18- 200912921 A stabilizer, a UV absorber, a toner, and an antistatic agent may be contained in the base film without impairing the properties of the film formed by melt film formation, for example, the transparency of the film. Wait. (Protective film) When the surface of the base film of the present invention is too smooth, the slidability is deteriorated, and it is difficult to perfectly wind up into a roll shape when it is alone. For this reason, in the case where the base film is laminated, the protective film which has been roughened on one side surface is provided to impart slidability and is wound into a roll shape. The thickness of the protective film is 10 to 100 μm. When the thickness is thinner than it is, the handleability is deteriorated, which is not preferable. When it is too thick, the thickness is increased when it is laminated on the base film, and the handleability is deteriorated, which is not preferable. The thickness of the protective film is not more than ±1.5 μm, preferably ±1 μm or less. When the thickness unevenness is larger than this, the unevenness of the protective film is transferred to the base film. When the protective film is peeled off from the laminated film and the base film is used as an optical member, it is a problem, which is not preferable. In particular, when a light transmitting layer as a high-density optical disk is used, the thickness unevenness of the protective film is preferably small. The protective film is made up of 50 weights. /. A protective film comprising the above polyethylene resin or polypropylene resin and having adhesiveness on one side is preferred. Polyethylene resin or polypropylene resin has a low Young's modulus and is generally used as a raw material for a protective film, which is economically preferable. The protective film may be adhered to one side after being formed into a base film to form a protective film, or a protective film having an adhesive side may be collectively formed by co-extruding a plurality of resins. Commercially available products such as EXCELGUARD FS made by CI Huacheng Co., Ltd. are suitable for use. 200912921 The adhesion of the protective film is preferably weak. When the adhesion is too strong, the film is peeled off and there is a residual adhesive component in the substrate film. Further, when the protective film is peeled off, there is a possibility that the base film is deformed, and there is a possibility that the uniformity of the base film is impaired. (Manufacturing method of laminated film) The laminated film of the present invention can be produced by laminating the above-mentioned base film and the above protective film under the conditions satisfying the following formulas (1) to (3). (Substrate film) The base film is made of a polycarbonate resin and has a thickness of 10 to 150 μm and a thickness of not more than ± 2 μm. The average value of the in-plane birefringence (Δ η) is The average enthalpy of the birefringence (Δη^) in the thickness direction of 0.00001 to 0.00017 is 0.00001 to 0.001. (Protective film) The thickness of the protective film is 10 to 100 μm, and the thickness is not more than ±1.5 μm. (Laminar conditions) " 'Lamination can be performed by applying tension to each of the symmetry and the protective film, and pressing it with a rubber roller or the like after the wrinkle-free state. This layer is subjected to '10<Τβ<200 (1) 10<TP<15 0 (2) TB/Tp ^ 10 (3) under the condition that the following formulas (1) to (3) are satisfied, TB It is the tension (N/m) per unit width of the base film at the time of lamination, and Tp is the tension per unit width of the protective film at the time of lamination - 20,129,921 (N/m). When the surface of the base film is too smooth, the 'slidability is deteriorated'. When it is alone, it is difficult to take up the roll-like shape. Therefore, 1' is a protective film in which the base film is laminated and the surface of one side is roughened. To give 'slidability' and take up into a roll. However, when the laminated film is formed, the 'slidability is improved', but the unevenness of the rough surface of the protective film is transferred. The fine unevenness is generated on the base film, and the unevenness causes the optical performance of the base film to be lowered. According to the present invention, in order to prevent fine unevenness of the base film, a protective film having a specific thickness unevenness can be used, and the tension between the base film and the protective film can be obtained in a predetermined range by laminating. Substrate film with fine unevenness. The preferred ranges of TB and TP are as follows. 3 0<ΤΒ<15 0 (1-1) 3 0<ΤΡ<100 (2-1) 1 ^ ΤΒ/Τρ ^ 5 (3-1) When ΤΒ and τΡ are too large, the unevenness of the protective film is transferred to The base film forms fine irregularities in the base film. Further, when the enamel and the enamel are too small, wrinkles or the like may occur during lamination, and it is not preferable to stratify uniformly. (Film roll) The present invention comprises a laminate film for an optical member obtained by winding the laminated film. In terms of productivity, the film width of the film roll is wider. The film width is preferably 600 to 2,000 mm, more preferably 800 to 2,000 mm. When performing edge trimming prior to becoming a film roll, it should be understood that the preferred film widths are trimmed after edge trimming. Further, the ruthenium which is suitable as the film width of the optical member varies depending on the purpose of use, and can be used by appropriately changing the film width by cutting the film roll or the like in 200912921. When the laminated film of the present invention is wound around a film roll, the preferred range of the take-up tension Tw (N/m) per unit width is as follows. 20<TW<200 (4)

It is more preferable that Tw satisfies the following formula (4-1). 20<TW<1 20 (4-1)

When the Tw is small, a film winding or the like is generated in the film roll, and a uniform film roll cannot be obtained, which is not preferable. When Tw is too large, it is not preferable because fine unevenness is generated in the base film f. The winding length of the film roll (winding length of the film) can be determined in terms of handling and productivity, and is not particularly limited, and is preferably in the range of 100 to 4,000 meters. (Optical member) After laminating the protective film, the laminated film of the present invention can be used as a component such as a compact disk or a touch panel. The optical disc is obtained by laminating a substrate thin film which is obtained by peeling the protective film from the above-mentioned laminated film, and bonding it to a substrate. The substrate film can fulfill the task of being a light transmitting layer of a disc. A Blu-ray Disc is exemplified as the optical disk of the light transmitting layer of the base film of the present invention. There are ROM types that can only be read by the information recording layer; R type that can be read and written once; and RE type that can be read, written, and erased. The substrate of the optical disk may be formed by, for example, melt-extruding a polycarbonate resin 'amorphous polyolefin resin and a methacrylic resin; and forming a thermosetting resin, particularly preferably a polycarbonate resin. -22 - 200912921 EXAMPLES Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited thereto. Further, the measurement and evaluation of the physical properties of the examples are as follows. (1) Viscosity average molecular weight The viscosity average molecular weight (M) of the polycarbonate resin is determined from the viscosity of the dichloromethane solution having a concentration of 〇7 g/dl at 20 ° C to determine the intrinsic viscosity U ]' and according to the following formula Calculated. V sP/c = [?7 ] + 〇.45x[?7 ]2c [7? ] = 1 . 2 3 χ 1 0 -4 Μ0.8 3 (where c = 〇_7, [ ”] is inherent Viscosity) (2) Film thickness The base film (polycarbonate film) and the protective film before laminating the protective film are thin rectangular specimens of 500 mm long and 50 mm wide from the center in the width direction of the film to both sides in the width direction. In the same manner, a sample of 1,0 mm mm Χ 50 mm size was taken. Five thin rectangular specimens were taken at intervals of 500 mm in the flow direction of the film. The long dimension direction of the thin rectangular sample (1, 0 00 mm long) The thickness of the central portion of the short dimension (50 mm long) was measured at 50 mm intervals using a micrometer made by MITUTOYO (measured at intervals of 50 mm from the end of the film at 25 mm, at 1 The root thin rectangular sample was measured at 20 o'clock. The average 値 of the thickness of the measurement point was determined as the film thickness. Further, these thin rectangular samples can also be used for measuring the thickness unevenness of the film described later. Birefringence (Δη) in the plane and birefringence (Δ nth) in the thickness direction. -23 - 2009 12921 (3) Insufficient thickness of the film When the measurement method of the micrometer of (2) above is used, there is a thickness unevenness which may exist outside the measurement point, such as a wide band or a thin stripe. In the case of the possibility of the measurement, the thickness unevenness was continuously measured using an Anritsu film thickness measuring instrument THICKNESS TESTER FCG601. The measurement sample was a thin rectangular sample after the measurement of (2) was used. For each of the samples, the thickness distribution in the long dimension was continuously measured using the above-mentioned film thickness gauge. The maximum thickness and minimum of the recorded thickness were obtained for the above five films (1, 〇〇〇 mm X 50 mm).値 difference (thickness range)' and the maximum thickness range is taken as the thickness unevenness of the film (4) in-plane birefringence (Δ n) and thickness direction birefringence (Δ nth) from 5 pieces ( 2) Measurement of the thin rectangular sample of the base film (polycarbonate film) used after the measurement is performed at a measurement position of (2) at a substantially center position to prepare a measurement sample of 50 mm square. Width direction energy 20 samples were obtained. Since there were five thin rectangular samples, one measurement sample was obtained. For these samples, a birefringence measuring machine made by the prince measuring machine (unit) was used. BRA - 2 1 AD Η, the hysteresis 测定 is measured by changing the incident angle by rotating the slow axis or the phase axis. The retardation 各 from each incident angle and the film thickness d of the measured position are used to obtain the refractive index ηχ, Ny and nz. And 'from these enthalpy, the in-plane birefringences Δ π and Δ nth are obtained according to the following formula. The average 値 of Δη was obtained from the average of all the measured data as Δη of the film. Further, the difference between the maximum 値 and the minimum △ of Δη is taken as the unevenness of the Δη. Similarly, the average 値 and unevenness are also taken for Δnth. Δ η = | η X - n y | -24- 200912921

Δ nth = I (nx + xy) / 2 - η z I (nx represents the refractive index in the direction of the slow axis in the plane of the film, ny is the refractive index in the direction of the phase axis, and the refractive index in the thickness direction of the nz is) The measurement procedures of the above (2) to (4) are carried out in the order of (3) measurement of film thickness unevenness, (4) in-plane and thickness direction birefringence measurement, and (2) thickness measurement. Since the measurement of (2) is a contact evaluation using a micrometer, the sample has a possibility of causing a flaw. (5) Total light transmittance of the base film ('A sample of 50 mm x 150 mm in size was taken at three positions in the width direction of the film, and it was measured using a turbidity meter COH-3 00A manufactured by Nippon Denshoku Industries Co., Ltd.). Five points were measured for each sample, and the average 値 of 15 points was used as the total light transmittance. (6) Evaluation of the yield when the optical disk was produced using the laminated film for optical members The optical disk medium (Blu-ray Disc) was as follows (Formation of the optical disk substrate) First, the resin for the optical disk substrate uses a viscosity average molecular weight of {

K '1 5,0 00 polycarbonate resin (PANLITE AD -55〇3) made by Teijin Chemical Co., Ltd., and formed using an optical injection molding machine (SD-40E manufactured by Sumitomo Heavy Industries Co., Ltd.) A disc substrate having an outer diameter of 120 mm 0, an inner diameter of 15 mm </», and a thickness of 1 · 1 mm. Further, at the time of injection molding, a stamper for a Blu-ray Disc ROM is attached to a mold to form a pit for forming data information on one surface. (Manufacturing of Blu-ray Disc) This disc substrate is supplied to a Blu-ray Disc laminating device (Shiba-25 - 200912921 MECHATRQNIC S (Μ E B IU S F - 1)) to manufacture a Blu-ray Disc. In addition to the optical disk substrate, the MEBIUS Fl' is also supplied with a target for magnetron sputtering of a KOBELCO-based silver alloy for forming a reflective film; and a laminated film which will be described later as a film for forming a light-transmitting layer; SK-810 manufactured by Sony Chemical & Information Device Co., Ltd., which is a resin for hard coating of Blu-ray Disc, is used as a resin for adhesion to a disc substrate. MEBIUS F-1 spin-coats a resin for adhesion by forming a reflective film of a silver alloy on a disc substrate. Here, the laminated film roll for forming the light-transmitting layer to be separately supplied is formed by drawing a base film, punching it into a disk shape, and bonding the punched film to the above-mentioned substrate, and irradiating with ultraviolet rays. A light transmissive layer is formed. Next, B 1 u - r a y D i s c is obtained by spin coating a resin for hard coating and irradiating it with ultraviolet rays to harden it. (Inspection of Blu-ray Disc) For the optical disk thus obtained, use the IQPC-Blu manufactured by dr_Schwab Inspection Technology GmbH to detect foreign matter and irregularities which are defects in the light transmission layer, and set it to have its length or width. If the disc of 300 μm or more is unacceptable, it is judged whether it is acceptable or not, and the yield of the optical disc manufacturing is obtained. The yield was obtained using a yield of about 300 discs. (7) Evaluation of the electric signal characteristics of the optical disk using the laminated film of the optical member. The optical disk of the above-mentioned (6) is used. The ODU-1000 made of PULSTEC Industrial Co., Ltd. is used to evaluate the sway, error rate (SER), etc. Signal characteristics. In the evaluation of -26 - 200912921, the deviation correction amount was adjusted in accordance with the average thickness of the light transmitting layer. (8) Melt viscosity of polycarbonate resin The melt viscosity of the polycarbonate resin particles used for film formation was measured using a flow characteristic meter CAPIROGRAPHY 1D manufactured by Toyo Seiki Co., Ltd. The capillary tube is used with a diameter of 1.0 mm and a length of 10 mm. The rotation speed was adjusted so that the shear rate was 1 0 0 s_1, and the melt viscosity at any temperature was measured. (9) Tension The tension applied to the base film and the protective film was determined from the measurement of the tension measuring device provided in each step and the film width at this time. Example 1 (Film formation of base film) An optical grade polycarbonate of a bisphenol A terpolymer manufactured by Teijin Co., Ltd. (trade name: AD-55〇3' Tg was 145 ° C, viscosity) The pellet having an average molecular weight of 15,000) was dried at 120 ° C for 3 hours using a vacuum dryer type tray dryer. This was placed in a heating hopper of a melt kneader which had been heated to 110 ° C, and melted and extruded at a cylinder temperature of 260 ° C. A stainless steel non-woven disc filter having an average opening of 1 〇 micrometer was used to remove foreign matter of the molten polymer. The film formation was carried out using the film forming apparatus shown in Fig. 1. In the die (1), a T-shaped die having a lip opening of 1 mm set at a molten resin temperature of 260 ° C was used (the polycarbonate resin had a melt viscosity of 2 60 P a . s ). The cooling rolls (2, 3, 4) use three diameters of 350 mm, and the temperature of the cooling roll (the first cooling roll (2)) where the molten resin is initially contacted is set to -27 - 200912921 to 1 40 °. C, the temperature of the second cooling roll (3)) was 135 ° C, and the temperature of the remaining rolls (3) was 130 °C. The distance between the front end portion of the lip and the first cooling roll surface (L1 in Fig. 2) is 15 mm, and the horizontal position of the first cooling roll (2) and the lip (L2 in Fig. 2) is visible from The rotation of the first cooling roller was viewed in a clockwise rotation position, and the front end of the lip was placed on the right side of the cooling roller from the center of 70 mm. The discharge amount of the polycarbonate resin and the conveyance speed of the film were adjusted so that the film thickness was 92 μm and the conveyance speed was 10 m/min. (Lamination of Protective Film) The lamination of the base film and the protective film is carried out by using a bonding apparatus as shown in Fig. 7 . The tension of the base film at the time of lamination is carried out by adjusting the speed difference between the nip rolls as shown by 5 and 8 in Fig. 1 so as to be 9 ON/m. The protective film was supplied to the bonding apparatus by applying a tension of 4 〇 N/m to a protective film (EXCELGUARD FS manufactured by CI Co., Ltd.) having a thickness of 30 μm from the position shown at 6 in Fig. 1 . The tension of the protective film is adjusted by the difference in speed between the protective film (6) and the nip roller (8). The characteristics of the base film and the protective film before bonding are shown in Table 1. (Winding) A film having a width of 1,000 mm was cut out at both ends of the laminated film, and a film roll was formed using a coiler shown in FIG. 1 (the winding length was 500 cm). . The take-up tension at this time can be adjusted using a speed difference between the nip roller and the winder (9) as shown in Fig. 8 of Fig. i, and is carried out at 80 N/m. (Cut strip) Using a slitter KE-70, manufactured by Kataoka Machinery Co., Ltd., a film roll having a width of 1,000 mm was cut into a width of 140 mm and a length of 400 m. Cutting -28 - 200912921 The coiler tension was 80 N/m ° (manufactured by Blu-ray Disc) Using the MEBIUS F-1 to manufacture Blu-ray Disc, the result was high yield. When the electric signal characteristics are evaluated on the discs that have passed the judgment, it is confirmed that the electric signal characteristics such as the sway and the error rate described in the BD-ROM White Paper issued by the Blu-ray Disc Association can be satisfied. On the other hand, the error rate determined to be bad is outside the specifications. From the above, it is known that the laminated film of the present invention is excellent as an optical member, and is particularly suitable for forming a light transmitting layer of a high-density optical disk. (Example 2) A roll of a laminated film was obtained in the same manner as in Example 1 except that the draw speed was adjusted so that the average thickness of the polycarbonate film of the base film was 78 μm. The characteristics of the base film and the protective film before bonding are shown in Table 1. The tension applied to the base film at the time of lamination was 9 ON/m, and the tension applied to the protective film was 4 〇N/m. After the strip was cut in the same manner as in Example 1, a Blu-ray Disc was produced. As a result, the disc is obtained in high yield. The disc system that has passed the judgment can satisfy the characteristics of electric signals such as sway and error rate. (Example 3) A roll of a laminated film was obtained in the same manner as in Example 1 except that the draw speed was adjusted so that the average thickness of the polycarbonate film of the base film was 67 μm. The characteristics of the base film and the protective film before bonding are shown in Table 1. The tension applied to the substrate film at the time of lamination was 8 ON/m, and the tension applied to the protective film of -29 - 200912921 was 40 N/m. After the strip was cut in the same manner as in Example 1, B]u_r ay D i s c was produced. As a result, the disc was obtained in high yield. The disc system that has passed the judgment can satisfy the characteristics of electric signals such as sway and error rate. Comparative Example 1 A roll of a laminated film was obtained in the same manner as in Example 1 except that the protective film was made of TORAYC 7332 manufactured by TORAY Co., Ltd. The characteristics of the base film and the protective film before bonding are shown in Table 1. ί After the strip was cut in the same manner as in Example 1, the Blu-r ay Disc was produced. The result is low yield. Comparative Example 2 A roll of a laminated film was obtained in the same manner as in Example 1 except that the protective film was made of SUN-A ICP (manufactured by SUN-A Co., Ltd.). The characteristics of the base film and the protective film before bonding are shown in Table 1. After the strip was cut in the same manner as in Example 1, a Blu_ray Disc was produced. The result is low yield. From the above experiments, it was found that the laminated film for an optical member of the present invention has optical characteristics suitable for forming a light transmitting layer of a high-density optical disk, and the optical disk can be manufactured at a high yield. -30 - 200912921 [Table 1] Substrate film thickness (micron) Δη Δη, π total light transmittance average 値 uneven average mean 値 uneven average 値 uneven rate (%) Example 1 92.3 ±0.9 0.000083 ±0.000013 0.00027 ± 0.000022 89 Example 2 78.1 ±1_1 0.000081 ±0.000012 0.00029 ±0.000021 89 Example 3 67.2 Soil 1_1 0.000089 ±0.000015 0.00031 ±0.000019 89 Comparative Example 1 92.3 ±0.9 0.000083 ±0.000013 0.00027 ±0.000022 89 Comparative Example 2 92.3 ±0.9 0.000083 ±0.000013 0.00027 ±0.000022 89 [Table 1]0 Continued) Protective film disc sloshing thickness (micron) Yield (Jitter) SER Electrical signal characteristics mean 値 unevenness (%) (%) (Quality determination of BD-ROM specifications) Example 1 30.1 ±0.9 85 4.76 4.4xl〇·5 Qualified Example 2 30.1 ±0.9 80 4.90 7.8xl0-5 Qualified Example 3 30.1 ±0.9 82 5.01 7.4xl0'5 Qualified Comparative Example 1 29.9 ±1,7 1 Comparative Example 2 70.2 ± 1.9 5 Effects of the Invention When the laminated film of the present invention is a release protective film, it has a small birefringence, a good surface smoothness, and an excellent optical directionality. The film. Moreover, since the laminated film of the present invention is excellent in slidability, it can be easily wound into a roll shape and is a film roll excellent in appearance. Further, when the laminated film of the present invention is used as a component such as a compact disc, the production rate of the defective product of the optical disc is small. Further, the film obtained by peeling off the protective film from the laminated film of the present invention exhibits excellent isotropic properties, and can be suitably used as a light transmitting layer of a compact disk. Further, the film obtained by peeling the protective film from the laminated film of the present invention as a light transmitting layer has excellent electrical signal characteristics such as shaking and error rate. Further, according to the method for producing a laminated film of the present invention, it is possible to provide a laminated film which can be a film having good surface smoothness after peeling off the protective film. Industrial use possibility

The laminated film of the present invention is used to manufacture an optical member such as an optical disk. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a film forming apparatus used in the embodiment. Fig. 2 is a schematic view showing the positions of the i-th cooling car and the front end of the lip of the film forming apparatus used in the embodiment. [Description of main components] 1 Die 2 1st cooling roll 3 2nd cooling roll 4 3rd cooling roll 5 ' 8 nip roll 6 Protective film 7 Fitting device 9 Coiler -32 -

Claims (1)

200912921 X. Patent application scope: 1. A film which is a laminated film for optical members formed by laminating a protective film on a substrate film, which is composed of a polycarbonate resin and satisfies (i) thickness It is 10 to 150 μm, (ii) the thickness is not more than ± 2 μm, and (iii) the average 値 of the birefringence (Δ η) in the plane is 〇·00001 to 0.00017' (iv) Birefringence in the thickness direction The average 値 of (Δη^) is 〇_〇〇〇〇1 〜0 · 0 0 1, and the protective film satisfies (i) a thickness of 10 to 100 μm, and (ii) a thickness of not more than ±1.5 μm. 2. The film of claim 1, wherein the polycarbonate resin is a resin obtained from a dihydroxy component of bisphenol A having at least 50 mol%. 3. The film of claim 1 or 2, wherein the polycarbonate resin has a viscosity average molecular weight of 1 2,000 to 19,0 Å. 4. The film of any one of claims 1 to 3, wherein the base film has a total light transmittance of 85 % or more. 5. The film of any one of claims 1 to 4, wherein the substrate film is a film formed by melt extrusion. The film according to any one of claims 1 to 5, wherein the protective film is composed of 50% by weight or more of a polyethylene resin or a polypropylene resin, and one side of which is an adhesive film. -33 - 200912921 7 - A film roll for an optical member is obtained by winding a laminated film according to any one of claims 1 to 6. An optical film obtained by laminating a base film obtained by peeling off a protective film onto a substrate as a light transmitting layer, is obtained from the laminated film according to any one of claims 1 to 6. 9. A method for producing a laminated film of an optical member comprising a laminated base film and a protective film, the base film being composed of a polycarbonate resin and satisfying (i) a thickness of 10 〜 150 μm, (ii) not more than ±2 μm in thickness, (iii) the average 値 of the birefringence (Δη) in the plane is 0.00001 to 0.000 1 7 ' (iv) Birefringence in the thickness direction (Δ nth) The average 値 is 0.0000 1 〜0 · 0 0 1, and the protective film satisfies (i) a thickness of 1 〇 〜1 〇〇 micron, and the thickness of (Π) is not more than ±1.5 μm. The conditions of the formulas (1) to (3) are carried out, 10 < Τ β < 200 (1) 10 < ΤΡ < 150 (2) 1 ^ ΤΒ / ΤΡ ^ 1 0 (3) (where ' TB is expressed in the layering The tension per unit width of the base film (N/m), and Tp is the tension (N/m) per unit width of the protective film when laminated. -34 -