JP5408004B2 - Manufacturing method of surface fine irregularities - Google Patents

Description

  The present invention relates to a method for producing a fine surface irregularity that can be used in various optical elements.

As the optical elements used in thin displays (for example, antireflection bodies, wire grid polarizers, light diffusers, optical phase difference bodies, etc.), surface fine irregularities with fine irregularities formed on the surface are widely used. Yes.
In recent years, large screens or mass production of thin displays have progressed, and surface fine irregularities used for optical elements have also been increased in area and mass production. Further, in the fine surface irregularities used for optical elements, it has been required to improve the accuracy of the irregular structure on the surface in order to improve the image quality of a thin display. Furthermore, what can adjust easily the pitch of a convex part, the ratio of the height and width of a convex part, etc. to a desired value was calculated | required.
In response to these requirements, Patent Documents 1 and 2 apply a coating liquid containing a hard resin to at least one surface of a heat-shrinkable resin film to form a hard layer, and then heat-shrink the heat-shrinkable resin film. A method of manufacturing a fine surface irregularity has been proposed.

International Publication No. 2007/097454 JP 2008-201029 A

However, even with the methods described in Patent Documents 1 and 2, it may not be possible to adjust the pitch of the concavo-convex pattern or the ratio between the height and width of the convex portion to a desired value, and in particular, to reduce the pitch of the concavo-convex pattern. Was difficult. Further, the hard resins described in Patent Documents 1 and 2 have a problem of high price.
Then, an object of this invention is to provide the manufacturing method of the surface fine unevenness | corrugation body which can manufacture the surface fine unevenness | corrugation body with a small pitch of an uneven | corrugated pattern easily and at low cost.

The present inventors speculated that the hard resin used in Patent Documents 1 and 2 has a low degree of polymerization dispersion, so that the processability is insufficient and it is difficult to obtain a desired pitch.
Further, the present inventors have found that the pitch can be reduced by reducing the thickness of the hard layer. Furthermore, in order to make the hard layer thin, it is necessary to apply a thin coating liquid containing a hard resin, and in order to apply a thin coating, it is necessary to suppress phase separation in the coating liquid. I found it.
In view of the above, the present inventors have studied a low-cost hard resin that has few impurities that cause phase separation, a high degree of polymerization dispersion, and a low price, and invented a method for manufacturing the following surface fine unevenness.

That is, the present invention includes the following aspects.
[1] A hard layer forming step of applying a resin solution to at least one surface of the heat shrinkable resin film and providing a hard layer having a smooth surface; and after the hard layer forming step, the heat shrinkable resin film is heated and shrunk. And deforming the hard layer so as to fold,
The resin contained in the resin solution is a resin obtained by polymerization by radical solution polymerization, and has a glass transition temperature higher than that of the resin constituting the heat-shrinkable resin film. Production method.
[2] The method for producing a fine surface irregularity according to [1], wherein the coating amount after drying the resin solution on the heat-shrinkable resin film is 1 to 100 mg / m ² .

  According to the method for producing a surface fine unevenness of the present invention, a surface fine unevenness having a small uneven pattern pitch can be produced easily and at low cost.

It is an expansion perspective view which expands and shows a part of surface fine unevenness | corrugation body obtained with one Embodiment of the manufacturing method of the surface fine unevenness | corrugation body of this invention. It is sectional drawing at the time of cut | disconnecting the surface fine unevenness | corrugation body of FIG. 1 in the orthogonal | vertical direction with the formation direction of an uneven | corrugated pattern.

<Surface fine irregularities>
One embodiment of a surface fine unevenness obtained by the method for producing a surface fine unevenness of the present invention will be described.
1 and 2 show the fine surface irregularities of the present embodiment. The surface fine concavo-convex body 10 of this embodiment includes a base material 11 and a hard layer 12 provided on one side of the base material 11, and the hard layer 12 has a concavo-convex pattern 12a.

  The concavo-convex pattern 12a of the surface fine concavo-convex body 10 in the present embodiment has a wavy unevenness substantially along the X-axis direction (longitudinal direction), and the wavy unevenness meanders. Further, the tip of the convex portion of the concavo-convex pattern 12a of this embodiment is rounded.

The resin constituting the hard layer 12 (hereinafter, referred to as a second resin.) And the glass transition temperature Tg ₂ of the resin constituting the substrate 11 (hereinafter, referred to as a first resin.) Between the glass transition temperature Tg ₁ of The difference (Tg ₂ −Tg ₁ ) is greater than 0 ° C., preferably 10 ° C. or more, more preferably 20 ° C. or more, and particularly preferably 30 ° C. or more. If _(Tg 2 -Tg ₁₎ the difference is 10 ° C. or higher, when manufacturing the surface fine unevenness body, it can be easily processed at a temperature between Tg ₂ and Tg _1. If the temperature between Tg ₂ and Tg ₁ is the processing temperature, the substrate 11 can be processed under the condition that the Young's modulus of the substrate 11 is higher than the Young's modulus of the hard layer 12, and as a result, the uneven pattern 12 a can be more easily formed on the hard layer 12. Can be formed.
In addition, it is not necessary to use a resin having a Tg ₂ exceeding 400 ° C. from the viewpoint of economic efficiency, and there is no resin having a Tg ₁ lower than −150 ° C., so (Tg ₂ -Tg ₁ ) is 550. It is preferably not higher than ° C., more preferably not higher than 200 ° C.
The difference in Young's modulus between the base material 11 and the hard layer 12 at the processing temperature when manufacturing the surface fine uneven body 10 is preferably 0.01 to 300 GPa because the uneven pattern 12a can be easily formed. More preferably, it is 1-10 GPa.
The processing temperature here is, for example, a heating temperature at the time of thermal contraction in the method for manufacturing the surface fine uneven body 10 described later. The Young's modulus is a value measured according to JIS K 7113-1995.

The glass transition temperature Tg ₁ of the first resin is preferably −150 to 300 ° C., more preferably −120 to 200 ° C. If there is no resin having a glass transition temperature Tg ₁ lower than −150 ° C. and the glass transition temperature Tg ₁ of the first resin is 300 ° C. or lower, the processing temperature (Tg ₂₎ when manufacturing the surface fine irregularities 10. And a temperature between ₁ and Tg ₁ ).

  The Young's modulus of the first resin at the processing temperature when manufacturing the fine surface irregularity 10 is preferably 0.01 to 100 MPa, and more preferably 0.1 to 10 MPa. If the Young's modulus of the first resin is 0.01 MPa or more, it is a hardness that can be used as the base material 11, and if it is 100 MPa or less, it is soft enough to follow and deform simultaneously when the hard layer 12 is deformed. That's it.

  Examples of the first resin include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, and polyamide.

Preferably has a glass transition temperature Tg ₂ of the second resin is 40 to 400 ° C., and more preferably 80 to 250 ° C.. If the glass transition temperature Tg ₂ of the second resin is 40 ° C. or higher, it is useful that the processing temperature for producing the fine surface asperity 10 can be room temperature or higher, and the glass transition temperature Tg ₂ This is because the use of a resin having a temperature exceeding 400 ° C. as the second resin is not necessary from the viewpoint of economy.

  The Young's modulus of the second resin at the processing temperature when manufacturing the fine surface irregularity 10 is preferably 0.01 to 300 GPa, more preferably 0.1 to 10 GPa. If the Young's modulus of the second resin is 0.01 GPa or more, sufficient hardness can be obtained from the Young's modulus at the processing temperature of the first resin, and the concavo-convex pattern 12a is maintained after the concavo-convex pattern 12a is formed. It is because it is scarcely necessary from the economical viewpoint to use as the second resin a resin that has sufficient hardness and a Young's modulus exceeding 300 GPa.

  Depending on the type of the first resin, examples of the second resin include polystyrene, acrylic resin (methyl methacrylate polymer, copolymer of methyl methacrylate and other acrylic monomers, and other than methyl methacrylate). Copolymer of two or more acrylic monomers), styrene-acrylic copolymer, styrene-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate copolymer, etc. can do. Among these, polystyrene and acrylic resin are preferable in that the uneven pattern can be more easily formed. A 2nd resin may be used individually by 1 type, and may use 2 or more types together.

  The thickness of the base material 11 is preferably 0.3 to 500 μm. If the thickness of the base material 11 is 0.3 μm or more, the surface fine uneven body 10 is difficult to break, and if it is 500 μm or less, the surface fine uneven body 10 can be easily thinned.

The thickness of the hard layer 12 is preferably 0.1 to 80 nm, more preferably 0.5 to 40 nm, and particularly preferably 1 to 15 nm. If the thickness of the hard layer 12 exceeds 80 nm, the pitch of the uneven pattern 12a may not be reduced, and if it is less than 0.1 nm, the formation of the hard layer 12 tends to be difficult.
The thickness of the hard layer 12 is preferably uniform. If the thickness of the hard layer 12 is uniform, the uniformity of the pitch is increased.
Further, a primer layer may be formed between the base material 11 and the hard layer 12 for the purpose of improving adhesion and forming a finer structure.

The most frequent pitch A of the concavo-convex pattern 12a is preferably 1 μm or less, more preferably 250 nm or less, further preferably 150 nm or less, and particularly preferably 100 nm or less. If the most frequent pitch A is 1 μm or less, the antireflection property when the surface fine irregularities 10 are used as an antireflection material and the polarization properties when used as a wire grid polarizer are further enhanced.
On the other hand, the most frequent pitch A is preferably 0.01 μm or more from the viewpoint that the uneven pattern 12a can be easily formed.

The most frequent pitch A and the degree of orientation of the concavo-convex pattern 12a are obtained according to the following method.
First, the top surface of the concavo-convex pattern is photographed with a surface optical microscope, and the image of the measured concavo-convex structure is converted into a grayscale image, and then two-dimensional Fourier transform is performed. The frequency (Z _F ) of the Fourier transform image is smoothed to obtain a position (X _Fmax , Y _Fmax ) indicating the maximum frequency other than the center of the Fourier transform image. Then, the most frequent pitch A is _obtained from the expression of the most frequent pitch A = 1 / {√ {square root over (X _Fmax ² + Y _Fmax ² )}}. The most frequent pitch may be regarded as an average value of each pitch.
The degree of orientation, first, by using the Fourier change image obtained above, creates a Fourier transform image rotated θ so that the maximum luminance portion matches on the X _F axis. Next, a parallel auxiliary line Y ′ _F is drawn on the Y _F axis passing through (X _Fmax , Y _Fmax ), the auxiliary line Y ′ _F is taken as the horizontal axis, and the luminance (Z _F axis) on the auxiliary line Y ′ _F is taken as the vertical axis. Y ' _F -Z _F diagram is created. Next, a Y ″ _F -Z _F diagram is created by dividing the value of the Y ′ _F axis of the Y ′ _F -Z _F diagram by the reciprocal (1 / A) of the most frequent pitch, and from this Y ″ _F -Z _F diagram The half width W of the peak (the width of the peak at a height at which the frequency is half the maximum value) is obtained. This half width represents the degree of orientation. The larger the degree of orientation, the more meandering the pitch.

When the fine surface irregularities 10 are used for a wire grid polarizer, the degree of orientation is preferably 1.0 or less, more preferably 0.5 or less, and particularly preferably less than 0.3. preferable. If the degree of orientation is 1.0 or less, the polarization characteristics of the wire grid polarizer can be further improved.
In order to set the degree of orientation to 1.0 or less, a method of applying a compressive stress necessary for manufacturing the surface fine unevenness 10 may be appropriately selected.
The degree of orientation is preferably 0.05 or more from the viewpoint of production.

The average depth B of the recesses 12b of the concavo-convex pattern 12a is preferably 10% or more when the most frequent pitch A is 100% (that is, an aspect ratio of 0.1 or more), and 30% or more (that is, the aspect) The ratio is more preferably 0.3 or more, and particularly preferably 100% or more. If the average depth B is 10% or more when the most frequent pitch A is 100%, the surface fine unevenness 10 is excellent in reflectivity when the surface fine unevenness 10 is used as an antireflection body. When used as a grid polarizer, sufficient polarization characteristics can be obtained.
Further, the average depth B is preferably 500% or less when the most frequent pitch A is 100% from the viewpoint that the uneven pattern 12a can be easily formed.

The average depth means the average of the depth from the peak of the convex part 12c of the concavo-convex pattern 12a to the bottom of the concave part 12b. The average depth B is obtained as follows. That is, the concavo-convex pattern 12a is observed with an atomic force microscope, and a cross-sectional view cut along the Y-axis direction is obtained from the observation. The depth to the bottom of one recess 12b is ½ of the sum of the distances in the Z direction from the peaks of the two adjacent protrusions 12c and 12c to the bottom of the recess 12b. That is, the depth b _i of the bottom of one concave portion 12b is defined as L _i that is the bottom depth of the concave portion 12b measured from the peak of the convex portion 12c on one side with respect to the concave portion 12b, and the peak of the convex portion 12c on the other side. B _i = (L _i + R _i ) / 2 where R _i is the depth of the bottom of the recess 12b measured from the above. The average value of the depth b _i of each recess 12b thus determined is the average depth B, because it is not practical to determine the depth of all the concave portions 12b, 10 or more randomly extracted The average depth B is obtained from 100 or less bi.

<Method for producing surface fine unevenness>
As an embodiment of the method for producing the surface fine unevenness of the present invention, a method for producing the surface fine unevenness of FIGS.
The manufacturing method of the surface fine unevenness | corrugation body of this embodiment forms the laminated sheet by providing the hard layer (henceforth a surface smooth hard layer) made from resin with the smooth surface on all the one surfaces of a heat-shrinkable resin film. A hard layer forming step, and a deformation step of deforming the heat-shrinkable resin film so as to fold the hard layer by heat-shrinking.
Here, the surface smooth hard layer is a layer having a center line average roughness of 0.1 μm or less described in JIS B0601.

(Hard layer forming process)
As the heat-shrinkable resin film, for example, a polyethylene terephthalate shrink film, a polystyrene shrink film, a polyolefin shrink film, a polyvinyl chloride shrink film, a polyvinylidene chloride shrink film, or the like can be used.
In this embodiment, a uniaxially stretched film is used as the heat-shrinkable resin film. Uniaxial stretching may be either longitudinal stretching or lateral stretching.
Further, the heat-shrinkable resin film is preferably stretched at a stretch ratio of 1.1 to 15 times, and more preferably stretched at 1.3 to 10 times.
The shrinkage ratio of the heat-shrinkable resin film is preferably 20 to 90%, and more preferably 35 to 75%. Here, the shrinkage rate is (shrinkage rate [%]) = {(length before shrinkage) − (length after shrinkage)} / (length before shrinkage) × 100 (however, length Is the length in the contraction direction). If the shrinkage rate is 20% or more, the surface fine irregularities can be produced more easily. However, it is difficult to produce a heat-shrinkable film having a shrinkage rate of 90% or less.
Since the heat-shrinkable resin film can easily form a surface smooth hard layer, the surface is preferably flat. Here, “flat” means that the center line average roughness according to JIS B0601 is 0.1 μm or less.

When the surface smooth hard layer is provided, a resin solution obtained by polymerization by radical solution polymerization is applied to a heat-shrinkable resin film and dried.
Here, radical solution polymerization is radical polymerization of a vinyl monomer having a vinyl group in a solvent. The resin solution is a second resin solution.

Examples of vinyl monomers include styrene monomers, acrylic monomers, acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, and ethylene.
Furthermore, examples of the styrene monomer include polystyrene and α-methylstyrene.
Examples of the acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl ( (Meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, (meth) acrylic acid alkyl ester monomers such as lauryl (meth) acrylate, (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, Carboxyl group-containing monomers such as fumaric acid and fumaric anhydride, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, polyethylene glycol (meth) acrylate A hydroxyl group-containing monomers bets, and the like. “(Meth) acrylate” is a general term for acrylate and methacrylate.
Examples of the solvent include ethyl acetate, toluene, hexane, cyclohexane, benzene, acetone, methyl ethyl ketone, and the like.

In the polymerization, a radical polymerization initiator is preferably used from the viewpoint of productivity.
The radical polymerization initiator is one that cleaves alone to generate a free radical. The generated radical undergoes a polymerization reaction by an addition reaction to a vinyl group and a hydrogen abstraction reaction. Examples of the radical polymerization initiator include methyl ethyl ketone peroxide, cyclohexanone peroxide, acetylacetone peroxide, 1,1-di (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-di (t -Hexylperoxy) cyclohexane, 1,1-di (t-butylperoxy) -2-methylcyclohexane, 1,1-di (t-butylperoxy) cyclohexane, 2,2-di (t-butylperoxy) ) Butane, n-butyl 4,4-di- (t-butylperoxy) valerate, 2,2-di (4,4-di- (t-butylperoxy) cyclohexyl) propane, p-menthane hydroperoxide , Diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl Dropper oxide, cumene hydroperoxide, t-butyl hydroperoxide, di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxide Oxy) hexane, t-butylcumyl peroxide, di-t-hexyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2.5-di (t-butylperoxy) hexyne-3, diisobu Tyryl peroxide, di (3,5,5-trimethylhexanoyl) peroxide, diauroyl peroxide, disuccinic acid peroxide, di- (3-methylbenzoyl) peroxide, dibenzoyl peroxide, di (4- Methylzenzoyl) peroxide, di-n-propylperoxydi Boneto, diisopropyl peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, and di -sec- butyl peroxydicarbonate and the like. These radical polymerization initiators may be used alone or in combination of two or more.

  In the polymerization, a chain transfer agent (for example, alkylthiol, α-methylstyrene dimer, etc.) for adjusting the molecular weight may be used as necessary, or a crosslinking agent (for example, a polymer is crosslinked). Divinylbenzene, triallyl isocyanurate, etc.) may be used.

  The polymerization temperature is not particularly limited as long as the temperature can be controlled, and is, for example, 50 to 120 ° C. However, when the polymerization rate is high, the polymerization may be carried out at 50 ° C. or lower, or the polymerization may be carried out at a boiling point or higher of the solvent. In the case of polymerization at a temperature higher than the boiling point of the solvent, a rectifier is provided on the reactor, and the evaporated solvent is cooled and refluxed.

  The mass average molecular weight of the second resin is preferably 1,000 to 10,000,000, more preferably 10,000 to 2,000,000, and particularly preferably 30,000 to 500,000. If the mass average molecular weight of the second resin is 1000 or more, the concave / convex pattern 12a can be more easily formed when the laminated sheet is contracted as will be described later, and if it is 10 million or less, the second resin is easily formed. Can be polymerized.

In this method, the second resin is a resin having a glass transition temperature higher than that of the first resin. By configuring the second resin with a resin having a glass transition temperature higher than that of the first resin, the concave / convex pattern 12a can be easily formed.
As described above, the difference between the glass transition temperature of the second resin and the glass transition temperature of the second resin is preferably 10 ° C or higher, more preferably 20 ° C or higher, and 30 ° C or higher. It is particularly preferred.

  Examples of resin solution coating methods include air knife coating, roll coating, blade coating, Mayer bar coating, gravure coating, spray coating, cast coating, curtain coating, die slot coating, gate roll coating, size press coating, and spin coating. And dip coating. Particularly preferred is gravure coating using a gravure roll having a diameter of 1 to 10 cm.

It is preferable that the coating amount of the resin solution into the heat shrinking resin film to 1 to 100 mg / ^{m 2.} If the coating amount of the resin solution is 1 mg / m ² or more, a sufficiently smooth surface hard layer can be formed, and an uneven pattern can be sufficiently formed. If it is 100 mg / m ² or less, the surface smooth hard layer can be formed. It can be made thin easily, and the mode pitch A of the concavo-convex pattern can be reduced more easily.

(Deformation process)
In the deformation step, the heat-shrinkable resin film is deformed by heat-shrinking to form a wavy uneven pattern 12a on the surface smooth hard layer.
Examples of the heating method for thermally shrinking the substrate 11 include a method of passing it through hot air, steam, or hot water. Among them, a method of passing it through hot water is preferable because it can be uniformly shrunk.
It is preferable to appropriately select the heating temperature at which the base material is thermally shrunk in accordance with the type of heat-shrinkable resin film to be used and the pitch A of the target concavo-convex pattern 12a and the depth B of the concave portion 12b.

(Function and effect)
In solution polymerization, a vinyl monomer and a resin produced by polymerization are dissolved in a solvent, so that it is not necessary to use an emulsifier or a dispersant, and a resin with high purity can be obtained. Therefore, since the phase separation of impurities in the coating liquid can be suppressed, there are few aggregates, and the coating liquid can be applied thinly. Thereby, a hard layer can be made thin easily and the pitch of the uneven | corrugated pattern 12a formed by a deformation | transformation process can be made small easily.
In radical polymerization, the degree of polymerization dispersion (molecular weight distribution, that is, mass average molecular weight Mw / number average molecular weight Mn) of the obtained resin is large, and usually 2 or more. Since a resin having a high degree of polymerization dispersion is excellent in processability, the hard layer can be easily deformed in the deformation step.
Moreover, radical polymerization of vinyl monomers in solution is universal.
Therefore, in the manufacturing method of the surface fine concavo-convex body in which the hard layer is formed from the resin obtained by radical solution polymerization, the surface fine concavo-convex body having a small pitch of the concavo-convex pattern 12a can be easily manufactured at low cost.

<Method for producing replica sheet of surface fine unevenness>
Using the surface fine irregularities obtained as described above as an original plate, a replica sheet of surface fine irregularities can also be produced. Examples of the method for producing a replica sheet include the following methods (a) to (c).
(A) After applying the uncured active energy ray-curable resin to the surface on which the uneven pattern of the surface fine irregularities is formed, and irradiating the active energy rays to cure the curable resin, And a step of peeling the cured coating film from the surface fine irregularities. Here, the active energy ray is usually an ultraviolet ray or an electron beam, but in the present invention, it includes a visible ray, an X-ray, an ion ray and the like.
(B) A step of applying an uncured liquid thermosetting resin to the surface on which the uneven pattern of the surface fine unevenness is formed, and heating and curing the liquid thermosetting resin, and then curing the coating. And a step of peeling the film from the surface fine irregularities.
(C) A step of bringing a sheet-like thermoplastic resin into contact with the surface of the surface fine irregularities on which the irregularity pattern is formed, and heating and softening the sheet-like thermoplastic resin while pressing the surface fine irregularities And then cooling and a method of peeling the cooled sheet-like thermoplastic resin from the surface fine irregularities.

It is also possible to produce a molded product for the secondary process using the fine surface irregularities, and to produce a replica sheet using the molded product for the secondary process. Examples of the molded product for the secondary process include a secondary process sheet. In addition, as the molded product for the secondary process, the surface fine irregularities are rounded and attached to the inside of the cylinder, plated with the roll inserted inside the cylinder, and the plating roll obtained by taking out the roll from the cylinder is Can be mentioned.
Specific methods using the molded product for the secondary process include the following methods (d) to (f).

(D) A step of performing metal plating of nickel or the like on the surface of the surface fine concavo-convex pattern on which the concavo-convex pattern is formed, and laminating a plating layer (material for transferring the concavo-convex pattern); An uncured active energy ray-curable resin is applied to the surface that is peeled off to produce a metal molded product for the secondary process, and then to the side of the secondary process molded product that is in contact with the concavo-convex pattern. The method which has a process to process, and after irradiating an active energy ray and hardening the said curable resin, the process which peels the hardened | cured coating film from the molded object for secondary processes.
(E) A step of laminating a plating layer (a material for transferring a concavo-convex pattern) on the surface on which the concavo-convex pattern of the surface fine concavo-convex pattern is formed; A step of producing a molded product for a process, a step of applying an uncured liquid thermosetting resin to a surface of the molded product for the secondary process that has been in contact with the concavo-convex pattern, and curing the resin by heating. And a step of peeling the cured coating film from the molded product for the secondary process.
(F) A step of laminating a plating layer (a material for transferring a concavo-convex pattern) on the surface on which the concavo-convex pattern of the surface fine concavo-convex pattern is formed; A step of producing a molding for process, a step of bringing a sheet-like thermoplastic resin into contact with the surface of the molding for secondary process that has been in contact with the concavo-convex pattern, and 2 of the sheet-like thermoplastic resin. A method comprising a step of heating and softening while pressing the molded product for the next step and then cooling, and a step of peeling the cooled sheet-like thermoplastic resin from the molded product for the second step.

  A specific example of the method (a) will be described. First, an uncured liquid active energy ray-curable resin is applied by a coater to the surface on which the uneven pattern of the web-like surface fine unevenness is formed. Subsequently, the surface fine unevenness | corrugation body which coated this curable resin is pressed by letting a roll pass, and the said curable resin is filled inside the unevenness | corrugation pattern of a surface fine unevenness | corrugation body. Then, an active energy ray is irradiated with an active energy ray irradiation apparatus, and curable resin is bridge | crosslinked and hardened. And a web-like replica sheet can be manufactured by making active energy ray hardening resin after hardening peel from a surface fine unevenness | corrugation body.

In the method (a), for the purpose of imparting releasability to the surface on which the uneven pattern of the surface fine unevenness is formed, before applying the uncured active energy ray-curable resin, a silicone resin, a fluororesin And the like, and a thickness of about 1 to 10 nm may be provided.
Examples of the coater for applying an uncured active energy ray-curable resin to the surface on which the uneven pattern of the surface fine unevenness is formed include a T-die coater, a roll coater, a bar coater, and a gravure coater.
Uncured active energy ray-curable resins include epoxy acrylate, epoxidized oil acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl / acrylate, polyene / acrylate, silicon acrylate, polybutadiene, and polystyrylmethyl. 1 selected from monomers such as prepolymers such as methacrylate, aliphatic acrylate, alicyclic acrylate, aromatic acrylate, hydroxyl group-containing acrylate, allyl group-containing acrylate, glycidyl group-containing acrylate, carboxy group-containing acrylate, halogen-containing acrylate The thing containing the component more than a kind is mentioned. The uncured active energy ray-curable resin is preferably diluted with a solvent or the like.
Moreover, you may add a fluororesin, a silicone resin, etc. to uncured active energy ray hardening resin.
When the uncured active energy ray-curable resin is cured with ultraviolet rays, it is preferable to add a photopolymerization initiator such as acetophenones and benzophenones to the uncured active energy ray-curable resin.

  After the uncured liquid active energy ray-curable resin is applied, the active energy rays may be irradiated after a substrate made of resin, glass or the like is bonded. Irradiation of active energy rays may be performed from any one of the base material and the surface fine irregularities having active energy ray permeability.

  The thickness of the cured active energy ray-curable resin sheet is preferably about 0.1 to 100 μm. If the thickness of the cured active energy ray-curable resin sheet is 0.1 μm or more, sufficient strength can be secured, and if it is 100 μm or more, sufficient flexibility can be secured.

In the above method, the surface fine irregularities are web-shaped, but may be a sheet of sheets. In the case of using a single sheet, a stamp method using a single sheet as a flat plate mold, a roll imprint method using a single sheet wound around a roll as a cylindrical mold, and the like can be applied. Moreover, the surface fine irregularities of the sheet may be arranged inside the mold of the injection molding machine.
However, in the method using these single sheets, in order to mass-produce replica sheets, it is necessary to repeat the process of forming the concavo-convex pattern many times. When the releasability between the active energy ray-curable resin and the surface fine unevenness is low, the uneven pattern is clogged when repeated many times, and the transfer of the uneven pattern tends to be incomplete.
On the other hand, since the surface fine irregularities are web-like, it is possible to continuously form an irregular pattern with a large area, so even if the number of repeated use of the surface fine irregularities is small, the required amount of replica sheets Can be manufactured in a short time.

In the methods (b) and (e), examples of the liquid thermosetting resin include uncured melamine resin, urethane resin, and epoxy resin.
Moreover, it is preferable that the hardening temperature in the method of (b) is lower than the glass transition temperature of a surface fine unevenness | corrugation body. This is because if the curing temperature is equal to or higher than the glass transition temperature of the surface fine irregularities, the irregular pattern of the surface fine irregularities may be deformed during curing.

In the methods (c) and (f), examples of the thermoplastic resin include acrylic resin, polyolefin, polyester, and the like.
The pressure when pressing the sheet-like thermoplastic resin against the molded product for the secondary process is preferably 1 to 100 MPa. If the pressure at the time of pressing is 1 MPa or more, the concavo-convex pattern can be transferred with high accuracy, and if it is 100 MPa or less, excessive pressurization can be prevented.
Moreover, it is preferable that the heating temperature of the thermoplastic resin in the method (c) is lower than the glass transition temperature of the surface fine irregularities. This is because if the heating temperature is equal to or higher than the glass transition temperature of the surface fine irregularities, the irregular pattern of the surface fine irregularities may be deformed during heating.
The cooling temperature after heating is preferably less than the glass transition temperature of the thermoplastic resin because the uneven pattern can be transferred with high accuracy.

  Among the methods (a) to (c), the method (a) using an active energy ray-curable resin is preferable in that heating can be omitted and deformation of the uneven pattern of the surface fine unevenness can be prevented.

In the methods (d) to (f), it is preferable that the thickness of the metallic secondary process molded product is about 50 to 500 μm. If the thickness of the metal secondary process molded product is 50 μm or more, the secondary process molded product has sufficient strength, and if it is 500 μm or less, sufficient flexibility can be secured.
In the methods (d) to (f), since a metal sheet with small deformation due to heat is used as a process sheet, an active energy ray curable resin, a thermosetting resin, or a thermoplastic resin is used as a material for the surface fine irregularities. Either of these can be used.

  In addition, in (d) to (f), the concave / convex pattern of the surface fine irregularities was transferred to a metal to obtain a molded product for the secondary process, but may be transferred to a resin to obtain a molded product for the secondary process. . Examples of the resin that can be used in this case include polycarbonate, polyacetal, polysulfone, and an active energy ray-curable resin used in the method (a). When the active energy ray-curable resin is used, the active energy ray-curable resin is sequentially applied, cured, and peeled in the same manner as in the method (a) to obtain a molded product for the secondary process.

  In the replica sheet obtained as described above, a concavo-convex pattern may be further formed on the surface opposite to the surface on which the concavo-convex pattern is formed.

  According to the above replica sheet manufacturing method, a replica sheet having a large surface fine unevenness can be mass-produced. Therefore, when mass-producing various optical elements, the replica sheet manufacturing method may be applied.

<Antireflection body>
The replica sheet 20 (see FIG. 1) obtained by the above production method has a concavo-convex pattern substantially the same as the concavo-convex pattern 12a of the surface fine concavo-convex body 10 or an inverted concavo-convex pattern. Since these concavo-convex patterns have a small mode pitch A and exhibit antireflection properties, they can be used as an antireflection body as they are.
That is, the wavy uneven pattern portion of the replica sheet shows an intermediate refractive index between the refractive index of air and the refractive index of the replica sheet (the refractive index of the base material 11), and the intermediate refractive index changes continuously. . Therefore, the reflectance of light can be made particularly low, and specifically, the reflectance can be made almost 0%.

  In the antireflection body, another layer may be provided on one side or both sides of the replica sheet. For example, an antifouling layer having a thickness of about 1 to 5 nm containing a fluororesin or a silicone resin as a main component is formed on the surface of the replica sheet on the side where the concavo-convex pattern is formed in order to prevent contamination of the surface. You may prepare.

Such an antireflection body is attached to, for example, an image display device such as a liquid crystal display panel or a plasma display, a light emitting portion tip of a light emitting diode, a surface of a solar cell panel, or the like.
When it is attached to the image display device, it is possible to prevent reflection of illumination, so that the visibility of the image is improved. When it is attached to the tip of the light emitting part of the light emitting diode, the light extraction efficiency is improved. When it is attached to the surface of the solar cell panel, the amount of light taken in increases, so that the power generation efficiency of the solar cell is improved.

  Moreover, the surface fine unevenness | corrugation body 10 can also be used as it is as an antireflection body.

<Wire grid polarizer>
A wire grid polarizing plate has the replica sheet 20 obtained by the said preparation method, and the discontinuous metal layer provided in the at least single side | surface of the replica sheet 20. FIG.
The discontinuous metal layer is linearly provided along the concave or convex portion of the concave / convex pattern of the replica sheet 20.
As a metal layer, the metal vapor deposition layer formed by vapor-depositing a metal and the nano metal coating layer formed by apply | coating the coating liquid containing a nano metal particle are mentioned, However, A metal vapor deposition layer is preferable. Since the metal vapor deposition layer does not require a heat treatment step when formed, damage to the replica sheet 20 due to heat can be prevented.

As a metal which comprises a metal vapor deposition layer, a well-known thing can be used if it is a metal which can be vapor-deposited, and metal compounds, such as germanium, tin, silicon, etc., carbon, and ITO (indium-tin oxide) are also included. Specifically, at least one selected from the group consisting of gold, aluminum, silver, carbon, copper, germanium, indium, magnesium, niobium, palladium, lead, platinum, silicon, tin, titanium, vanadium, zinc, bismuth, and ITO. Preferably it is a seed. More preferred are aluminum, nickel, zinc, tin, chromium, cobalt, gold, silver, copper, and ITO, and particularly preferred is aluminum and / or nickel for reasons such as price and stability of metallic luster.
The surface of the metal vapor deposition layer may be oxidized by contact with air.

Examples of metal deposition methods include physical vapor deposition (PVD) and chemical vapor deposition (CVD).
Examples of the physical vapor deposition method include resistance heating vapor deposition, electron beam vapor deposition, high frequency induction vapor deposition, molecular beam epitaxy vapor deposition, ion plating vapor deposition, ion beam deposition vapor deposition, and sputter vapor deposition. Examples of the chemical vapor deposition method include thermal CVD, plasma CVD, photo CVD, epitaxial CVD, atomic layer CVD, metal organic chemical vapor deposition, and catalytic chemical vapor deposition. Of these, resistance heating vapor deposition, electron beam vapor deposition, and sputter vapor deposition are preferred because of their versatility.
The number of times of vapor deposition may be one time, or two or more times.

In the metal deposition, it is preferable to apply oblique deposition in which the metal is deposited from an oblique direction with respect to the surface on which the metal is deposited. According to the oblique deposition, the metal can be easily deposited on the upper part of one side surface of the convex portion of the concave-convex pattern of the replica sheet 20, and the convex portion serves as a shield to generate a portion where the metal is not deposited. . Therefore, it is possible to form a wire grid polarizer in which fine-line metal layers are arranged substantially in parallel.
In oblique vapor deposition, the normal direction (hereinafter referred to as “H-line direction”) with respect to the X-axis direction (longitudinal direction) and the Y-axis direction (width direction) of the replica sheet 20 and the movement direction (hereinafter referred to as “H-line direction”) of the evaporated metal. The angle (oblique deposition angle) with respect to “J-line direction” is not particularly limited. However, since a linear metal deposition layer can be provided more easily, it is preferably 30 ° or more, and 40 ° More preferably, it is more preferably 55 ° or more, and particularly preferably 70 ° or more. The upper limit of the oblique deposition angle is 90 °, but it is preferably 80 ° or less in order to sufficiently deposit the metal.
In addition, since the polarization characteristics become higher, the direction of an imaginary line obtained by projecting the X-axis direction of the replica sheet 20 and the movement direction of the evaporated metal onto the XY plane (hereinafter referred to as “I-line direction”). ) Is preferably 60 to 120 °, and more preferably 80 to 100 °.

In addition, when the replica sheet 20 is a single wafer, batch-type vapor deposition can be applied, and when the replica sheet 20 is web-shaped, roll-to-roll vapor deposition can be applied.
In roll-to-roll deposition, when the angle between the transport direction of the replica sheet 20 and the X-axis direction of the replica sheet 20 is 45 ° or less, the obliquely deposited sheet is rotated 180 ° horizontally to further deposit metal. It is preferable. If the oblique deposition sheet is rotated 180 ° and then the metal is deposited, the metal can be uniformly deposited on the top of the convex portion. Thereby, since a uniform polarization plane can be obtained, polarization characteristics can be made uniform.

The thickness of the metal vapor deposition layer is preferably 1 to 100 nm. If the thickness of the metal vapor deposition layer is not less than the lower limit value, sufficient light reflectivity can be obtained, and if the thickness is not more than the upper limit value, the light transmittance of the wire grid polarizer can be sufficiently increased.
In addition, when the metal vapor deposition layer is formed by oblique vapor deposition and the oblique vapor deposition angle is 0 to 30 °, the metal vapor deposition layer can be easily formed. A thickness of 20 nm is particularly preferable. When the oblique vapor deposition angle is 30 to 90 °, the metal vapor deposition layer can be easily formed, so that it is more preferably 5 to 100 nm, and particularly preferably 10 to 60 nm.

  As a metal seed | species of a nano metal coating layer, nano silver, nano gold, nano copper, nano platinum, etc. are mentioned, Nano silver is preferable. Here, the nano metal is a metal dispersion having an average particle size of 0.1 to 200 nm. Here, the average particle diameter is a value measured by a dynamic light scattering method (for example, NANO-ZS manufactured by Malvern is known as a measuring device). When the particle size of the nanometal exceeds 100 nm, the polarization characteristics may be insufficient. Nanometals less than 0.1 nm are difficult to produce. The particle size of the nanometal is more preferably 1 to 100 nm, particularly preferably 5 to 70 nm.

The nanometal coating layer is formed by applying and drying a dispersion containing nanometal. By applying, the nano metal enters the bottom of the concave portion of the concave / convex pattern, but hardly adheres to the upper portion of the convex portion. Therefore, since the metal layer is formed only in the concave portion, a wire grid polarizer in which thin metal layers are arranged substantially in parallel can be formed.
Examples of the method for applying a dispersion containing nanometal include air knife coating, roll coating, blade coating, Mayer bar coating, gravure coating, spray coating, cast coating, curtain coating, die slot coating, gate roll coating, and size press coating. , Spin coating, dip coating and the like.
After the dispersion is applied and dried, it is preferably fired (heat treatment) in order to obtain a high metallic luster and increase the light reflectivity.

By depositing a metal on the replica sheet as described above, or by applying a dispersion containing nano metal, a wire grid polarizer in which fine-line metal layers are arranged in parallel can be easily manufactured.
The wire grid polarizer transmits light that vibrates perpendicularly to the longitudinal direction of the metal layer and reflects light that vibrates parallel to the longitudinal direction of the metal layer. By rotating the oscillation direction of the reflected light by 90 ° and then entering again, strong linearly polarized light can be obtained without loss due to absorption.
Such a wire grid polarizer can be preferably used for various known thin displays (for example, a liquid crystal display (LCD), an organic EL display, an inorganic EL display, etc.).

  Moreover, you may produce a wire grid polarizer by providing a discontinuous metal layer in the uneven | corrugated pattern 12a of the surface fine unevenness | corrugation body 10 instead of a replica sheet.

In addition, this invention is not limited to the said embodiment. For example, you may manufacture a surface fine unevenness | corrugation body using a biaxially stretched film as a heat-shrinkable resin film. When a biaxially stretched film is used as the heat-shrinkable resin film, a film that has been stretched laterally after longitudinal stretching (sequentially stretched) is preferred to one that has been stretched simultaneously in the longitudinal and transverse directions. The concavo-convex pattern of the surface fine concavo-convex body obtained using the biaxially stretched film becomes concavo-convex not along a specific direction.
A replica sheet can also be produced from a fine surface irregularity obtained using a biaxially stretched film. The replica sheet can be used as an antireflection body.

In the following examples, the mass average molecular weight and the degree of polymerization dispersion (Mw / Mn) were measured using gel permeation chromatography. A polystyrene having a known molecular weight was used as a molecular weight standard. The measurement conditions were a TSKgel SuperHZ series manufactured by Tosoh Corporation as a column, tetrahydrofuran as an eluent, a flow rate of 0.35 mL, and a temperature of 40 ° C.
The glass transition temperature was measured by a differential scanning calorimetry (DSC6200, manufactured by SII Nano Technology).

<Example 1>
To a solution of an acrylic resin (LH-101 manufactured by Fujikura Kasei Co., Ltd., mass average molecular weight 45000, polymerization dispersion degree 3, polymerization solvent toluene, specific gravity 1.19) obtained by synthesis by radical solution polymerization and having a glass transition temperature of 100 ° C. 3% by mass of glycol monomethyl ether was added to 100% by mass of the acrylic resin solution to prepare a resin solution having an acrylic resin concentration of 0.4% by mass.
Next, after drying the resin solution by gravure coating (gravure count 180) on both sides of a polyethylene terephthalate shrink film (SC802 manufactured by Toyobo Co., Ltd.) having a thickness of 40 μm that mainly heat-shrinks in one axial direction (width direction). The coating amount was 20 mg / m ² . Thereby, the lamination sheet in which the surface smooth layer was formed on both surfaces of the polyethylene terephthalate shrink film was obtained.
Next, the laminate sheet cut into 1 m square was put into a dryer at 100 ° C. for 1 minute and heat-shrinked to obtain a shrink sheet in which a hard layer made of an acrylic resin was formed on both sides of a polyethylene terephthalate film. The obtained shrinkable sheet had a size of 40 cm (main shrinkage direction) × 98 cm (direction perpendicular to the main shrinkage direction).

<Example 2>
To a solution of an acrylic resin (mass average molecular weight 65000, polymerization dispersity 3, polymerization solvent toluene / ethyl acetate, specific gravity 1.19) obtained by synthesis by radical solution polymerization and having a glass transition temperature of 155 ° C., methyl isobutyl ketone is acrylic. 3% by mass of propylene glycol monomethyl ether with respect to 100% by mass of the resin solution was added by 3% by mass with respect to 100% by mass of the acrylic resin solution to prepare a resin solution having an acrylic resin concentration of 0.2% by mass.
The above resin solution is applied after drying by gravure coating (gravure count 180) on one side of a 25 μm thick polyethylene terephthalate shrink film (SC807 manufactured by Toyobo Co., Ltd.) that mainly heat-shrinks in one axial direction (longitudinal direction). Coating was performed so that the work amount was 10 mg / m ² . This obtained the lamination sheet in which the surface smooth layer was formed in the single side | surface of a polyethylene terephthalate shrink film.
Next, the laminate sheet cut into 1 m square was put in a dryer at 150 ° C. for 1 minute and heat-shrinked to obtain a shrink sheet in which a hard layer made of an acrylic resin was formed on both surfaces of a polyethylene terephthalate film. The obtained shrinkable sheet had a size of 40 cm (main shrinkage direction) × 98 cm (direction perpendicular to the main shrinkage direction).

<Example 3>
To a solution of an acrylic resin (mass average molecular weight 65000, polymerization dispersity 3, polymerization solvent toluene / butyl acetate, specific gravity 1.19) obtained by synthesis by radical solution polymerization and having a glass transition temperature of 155 ° C., methyl isobutyl ketone is added to acrylic resin. 3% by mass of propylene glycol monomethyl ether with respect to 100% by mass of the resin solution was added by 3% by mass with respect to 100% by mass of the acrylic resin solution to prepare a resin solution having an acrylic resin concentration of 0.2% by mass.
Next, after drying the resin solution on one side of a 25 μm-thick polyethylene terephthalate shrink film (SC807 manufactured by Toyobo Co., Ltd.) that mainly heat-shrinks in one axial direction (longitudinal direction) by gravure coating (gravure count 180) The coating amount was 20 mg / m ² . This obtained the lamination sheet in which the surface smooth layer was formed in the single side | surface of a polyethylene terephthalate shrink film.
Next, the laminate sheet cut into 1 m square was put in a dryer at 150 ° C. for 1 minute and heat-shrinked to obtain a shrink sheet in which a hard layer made of an acrylic resin was formed on both surfaces of a polyethylene terephthalate film. The obtained shrinkable sheet had a size of 40 cm (main shrinkage direction) × 98 cm (direction perpendicular to the main shrinkage direction).

<Example 4>
To a solution of an acrylic resin (LH-101 manufactured by Fujikura Kasei Co., Ltd., mass average molecular weight 45000, polymerization dispersion degree 3, polymerization solvent toluene, specific gravity 1.19) obtained by synthesis by radical solution polymerization and having a glass transition temperature of 100 ° C. 3% by mass of glycol monomethyl ether was added to 100% by mass of the acrylic resin solution to prepare a resin solution having an acrylic resin concentration of 1.0% by mass.
Next, the resin solution is applied by gravure coating (gravure count 180) on both surfaces of a 50 μm thick polyethylene terephthalate shrink film (Mitsubishi Resin HXIPET LX-61S) that mainly heat-shrinks in one axial direction (width direction). The coating amount after drying was 90 mg / m ² . Thereby, the lamination sheet in which the surface smooth layer was formed on both surfaces of the polyethylene terephthalate shrink film was obtained.
Next, the laminate sheet cut into 1 m square was put into a dryer at 100 ° C. for 1 minute and heat-shrinked to obtain a shrink sheet in which a hard layer made of an acrylic resin was formed on both sides of a polyethylene terephthalate film. The obtained shrinkable sheet had a size of 45 cm (main shrinkage direction) × 94 cm (direction perpendicular to the main shrinkage direction).

<Comparative Example 1>
In a suspension dispersion of acrylic resin (Acrbase MH-101-10, manufactured by Fujikura Kasei Co., Ltd., mass average molecular weight 560000, polymerization dispersion degree 3, specific gravity 1.19) obtained by synthesis by radical suspension polymerization and having a glass transition temperature of 100 ° C. Then, 3% by mass of propylene glycol monomethyl ether was added to 100% by mass of the acrylic resin suspension dispersion to obtain a thermoplastic resin dispersion having an acrylic resin concentration of 0.4% by mass.
On both surfaces of a 40 μm thick polyethylene terephthalate shrink film (SC802 manufactured by Toyobo Co., Ltd.) that mainly heat-shrinks in one axial direction (width direction), the thermoplastic resin dispersion is applied by gravure coating (gravure count 180). the coating amount after drying was coated so as to be 20 mg / ^{m 2.} Thereby, the lamination sheet in which the surface smooth layer was formed on both surfaces of the polyethylene terephthalate shrink film was obtained. However, the coating surface had white turbidity unevenness on the surface and could not be applied uniformly.
Next, the laminate sheet cut into 1 m square was put into a dryer at 100 ° C. for 1 minute and heat-shrinked to obtain a shrink sheet in which a hard layer made of an acrylic resin was formed on both sides of a polyethylene terephthalate film. The obtained shrinkable sheet had a size of 40 cm (main shrinkage direction) × 98 cm (direction perpendicular to the main shrinkage direction).

(Measure the most frequent pitch, degree of orientation, and average depth)
The exposed surfaces of the hard layers of Examples 1 to 4 and Comparative Example 1 were observed with an atomic force microscope (Nanoscope III manufactured by Beiko Japan). As a result, in Examples 1 to 4, a fine uneven structure was formed on the entire exposed surface of the hard layer. About the comparative example 1, the fine concavo-convex structure was formed in a part of exposed surface of a hard layer.
The most frequent pitch A and the degree of orientation of the concavo-convex pattern were determined as follows.
That is, after converting the measured image of the concavo-convex structure into a grayscale image, a two-dimensional Fourier transform was performed. The frequency (Z _F ) of the Fourier transform image was smoothed, and the position (X _Fmax , Y _Fmax ) indicating the maximum frequency other than the center of the Fourier transform image was obtained. Then, the most frequent pitch A was obtained from the equation of the most frequent pitch A = 1 / {√ {square root over (X _Fmax ² + Y _Fmax ² )}}.
Further, the degree of orientation was determined using the Fourier transform image. That is, first, using the above-described Fourier transform image, a Fourier transform image rotated by θ so that the maximum luminance portion matches on the _XF axis was created. Next, a parallel auxiliary line Y ′ _F is drawn on the Y _F axis passing through (X _Fmax , Y _Fmax ), the auxiliary line Y ′ _F is taken as the horizontal axis, and the luminance (Z _F axis) on the auxiliary line Y ′ _F is taken as the vertical axis. Y ' _F -Z _F diagram was created. Next, a Y ″ _F- Z _F diagram is created by dividing the value of the Y ′ _F axis of the Y ′ _F- Z _F diagram by the reciprocal (1 / A) of the most frequent pitch, and from this Y ″ _F- Z _F diagram The half width W of the peak (the width of the peak at a height at which the frequency is half the maximum value) was determined. This half width represents the degree of orientation.
Moreover, the depth to the bottom of 10 recessed parts was measured with the cross-sectional image obtained by atomic force microscope measurement, and the average depth was calculated | required from the measurement result.
Table 1 shows the most frequent pitch, the degree of orientation, and the average depth.

(Measurement of light reflectance and light transmittance)
In order to evaluate the performance as an optical element for the shrinkable sheets of Examples 1 to 3, using a spectrophotometer (V-7200) manufactured by JASCO Corporation, light reflectance and light transmission with respect to visible light having a wavelength of 550 nm The rate was measured.
In addition, about the shrinkable sheet of the comparative example 1, when it measured with the atomic force microscope, the surface fine concavo-convex structure was not partially formed, and it was cloudy. From this, it was clear that it could not be used as an optical element, so evaluation was not performed.

(Evaluation when using wire grid polarizer)
A wire grid polarizer was produced as follows using the shrinkable sheets of Examples 1, 2, and 3.
Aluminum was vapor-deposited with a thickness of 30 nm on a hard layer on one side of the obtained shrinkable sheet using a resistance heating vapor deposition apparatus (EX-400 manufactured by ULVAC). At that time, the oblique deposition was performed at an oblique deposition angle of 60 ° and an angle of 90 ° between the I-line direction and the X-axis direction. Thereby, the aluminum vapor deposition layer was formed on the upper part of the slope of the convex part orientated substantially in the X-axis direction, and a wire grid polarizer in which the thin aluminum vapor deposition layers were arranged in parallel was obtained.
The polarization characteristics of the obtained wire grid polarizer were measured by KOBRA (manufactured by Oji Scientific Instruments). The measurement results are shown in Table 1.

The shrinkage sheets of Examples 1 to 4 using those obtained by radical solution polymerization as the thermoplastic resin constituting the hard layer had a small frequent pitch. Moreover, the light reflectance was small and the light transmittance was large. Moreover, the wire grid polarizer using the shrinkable sheets of Examples 1 and 3 had sufficient polarization and light transmittance.
The shrinkage sheet of Comparative Example 1 using the one obtained by radical suspension polymerization as the thermoplastic resin constituting the hard layer had a large frequent pitch. Moreover, since it was cloudy, it could not be used as an antireflector and a wire grid polarizer.

DESCRIPTION OF SYMBOLS 10 Surface fine unevenness | corrugation 11 Base material 12 Hard layer 12a Concave / convex pattern 12b Concave part 12c Convex part 20 Replica sheet

Claims (2)

A hard layer forming step in which a resin solution is applied to at least one surface of the heat-shrinkable resin film and a hard layer having a smooth surface is formed; and after the hard layer forming step, the heat-shrinkable resin film is heat-shrinked to form the hard layer A deformation step of deforming the layers so as to fold,
The resin contained in the resin solution is a resin obtained by polymerization by radical solution polymerization, and has a glass transition temperature higher than that of the resin constituting the heat-shrinkable resin film. Production method. The manufacturing method of the surface fine unevenness | corrugation of Claim 1 which makes the coating amount after drying of the resin solution to a heat-shrinkable resin film 1-100 mg / m < ² >.

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