KR102473934B1 - Laminate and method for producing laminate - Google Patents

Abstract

An object of the present invention is to provide a laminate having uniform light diffusing properties and a method for producing the same.
As a means for solving these problems, a laminate formed by laminating an overlaminate film on a light diffusion control film, wherein the light diffusion control film has a predetermined internal structure, and in the laminated surface of the laminate, the light The movement direction at the time of forming the diffusion control film is the long direction, and the direction perpendicular to the long direction is the short direction, and the maximum value of the phase difference Re (nm) measured along the short direction of the overlaminated film is Re _max and when the minimum value is set to Re _min , a laminate or the like characterized by satisfying a predetermined relational expression (1) is provided.
(Re _max -Re _min )/(Re _max +Re _min )×100<35 (%) (1)

Description

Laminate and method for producing a laminate {LAMINATE AND METHOD FOR PRODUCING LAMINATE}

The present invention relates to a laminate and a method for manufacturing the laminate.

In particular, as a laminate of a light diffusion control film and an overlaminate film obtained by photocuring a coating layer composed of a composition for a light diffusion control film in a laminated state with an overlaminate film, the light diffusion control film has a light diffusion property. It relates to a laminate that is uniform regardless of locations on the film plane, and a method for producing such a laminate.

BACKGROUND ART [0002] In the field of optical technology to which, for example, liquid crystal display devices and projection screens belong, use of a light diffusion control film has been proposed.

Such a light-diffusion control film exhibits a constant light-diffusion state in a specific incident angle range (hereinafter sometimes referred to as "light-diffusion incident angle region"), and in an incident angle range that deviates from the light-diffusion incident angle region, the incident light It transmits as it is or has a light-diffusion characteristic that shows a different light-diffusion state from the light-diffusion state in the light-diffusion incidence angle region.

Although various aspects are known as such a light diffusion control film, in particular, in the film, a column structure formed by placing a plurality of columnar objects having a relatively high refractive index in a region having a relatively low refractive index. A light diffusion control film having is widely used.

Further, as another type of light diffusion control film, a light diffusion control film having a louver structure formed by alternately arranging a plurality of plate-shaped regions having different refractive indices along an arbitrary one direction along the film surface in the film is widely used. .

By the way, the light diffusion control film having such a column structure or louver structure is a coating layer obtained by applying a composition for a light diffusion control film containing two or more types of polymeric compounds having different refractive indices in a film form, using a predetermined method. It is known that it is obtained by irradiating an active energy ray.

That is, a light diffusion control film having a predetermined internal structure can be obtained by curing while phase-separating two or more types of polymeric compounds in the coating layer by irradiating the coating layer with a predetermined active energy ray whose advancing direction is controlled. have.

However, when the application layer is directly irradiated with a predetermined active energy ray, a problem arises that it becomes difficult to form a predetermined internal structure to the end of the film thickness direction, that is, to the upper surface of the film.

That is, although a predetermined internal structure can be formed in the lower part in the film thickness direction, a problem arises that an internal structure unformed region is generated in the upper part.

Therefore, a technique for forming a predetermined internal structure up to the upper surface of a film without generating an internal structure unformed region is disclosed (see Patent Document 1, for example).

That is, in Patent Document 1, a light irradiation mask bonding step of bonding a light irradiation mask having a haze value of 1.0 to 50.0% to one side of a photocurable uncured resin composition layer, and a light irradiation mask bonding process after the light irradiation mask bonding process. Disclosed is a method for producing an anisotropic optical film whose diffusivity changes depending on the angle of incidence of light, comprising a curing step of forming an anisotropic diffusion layer by curing an uncured resin composition layer by irradiating light therethrough. .

It is also described that the surface roughness of the light irradiation mask is 0.05 to 0.50 μm, and the oxygen transmission coefficient of the light irradiation mask is 1.0 × 10 ^{- 11} cm 3 (STP) cm / (cm 2 s Pa) or less. .

That is, a technique for suppressing generation of an internal structure unformed region is disclosed by photocuring a coating layer made of a composition for a light diffusion control film in a state in which a predetermined overlaminate film is laminated.

Japanese Unexamined Patent Publication No. 2016-194687 (scope of claims)

However, even when the light irradiation mask described in Patent Literature 1 is used, it is difficult to stably suppress the generation of the internal structure unformed region.

In particular, in one continuous light-diffusion control film with a width, there was a location where the internal structure unformed region did not occur, and a location where it did occur was observed. From this, the problem that the light-diffusion characteristic also changes according to the incident location of light in the film surface, and the light-diffusion characteristic becomes non-uniform as a whole appeared.

Therefore, in view of the above circumstances, the inventors of the present invention have diligently made efforts to set the non-uniformity of the phase difference measured along a predetermined direction within the overlaminated film surface to a value within a predetermined range, thereby generating an internal structure unformed region. The present invention was completed by finding that the internal structure can be uniformly formed even when it does not occur or when it occurs.

That is, an object of the present invention is a laminate of a light diffusion control film and an overlaminate film obtained by photocuring in a state in which an application layer made of a composition for a light diffusion control film is laminated with an overlaminate film, wherein the light diffusion control The object of the present invention is to provide a layered product in which the light-diffusing property of the film is uniform regardless of locations on the film surface, and a method for manufacturing such a layered product.

According to the present invention, as a laminate in which an overlaminate film is laminated on at least one surface of a light diffusion control film derived from a composition for a light diffusion control film, wherein the light diffusion control film is formed in a low refractive index region in a plurality of high-density regions. While having a refractive index region, the high refractive index region has an internal structure formed by extending in the thickness direction, and the moving direction at the time of forming the light diffusion control film is a long direction within the laminated surface of the laminate , When the direction perpendicular to the long direction is the short direction, and the maximum value of the retardation Re (nm) measured along the short direction of the overlaminated film is Re _max and the minimum value is Re _min , the following A laminate characterized by satisfying the relational expression (1) is provided, and the above-described problem can be solved.

(Re _max -Re _min )/(Re _max +Re _min )×100<35 (%) (1)

That is, according to the laminate of the present invention, since the non-uniformity of the retardation Re measured along the predetermined direction within the overlaminate film surface is set to a value within a predetermined range, the overlaminate film for the coating layer composed of the composition for light diffusion control film By curing in the laminated state, it is possible to obtain a laminate of the light diffusion control film and the overlaminated film having uniform light diffusion properties regardless of locations in the film surface.

Further, in constituting the laminate of the present invention, it is preferable to set the length of the overlaminate film in the short direction to a value within the range of 100 to 10000 mm.

By comprising in this way, a laminate with sufficient length in the short direction can be obtained, and furthermore, a light diffusion control film with sufficient length in the short direction can be obtained.

Further, in constituting the laminate of the present invention, it is preferable to set the median value of the retardation Re of the overlaminate film to a value within the range of 1000 to 3000 nm.

With this configuration, it is possible to effectively suppress the occurrence of internal structure unformed regions in the light diffusion control film.

Further, in constituting the laminate of the present invention, it is preferable to set the film thickness of the overlaminate film to a value within the range of 5 to 5000 µm.

By configuring in this way, an overlaminated film that more stably satisfies relational expression (1) can be obtained.

Further, in constituting the laminate of the present invention, as an internal structure in the light diffusion control film, a column formed by interleaving a plurality of columnar objects having a relatively high refractive index in the film thickness direction in a region having a relatively low refractive index. It is desirable to include a structure.

With this configuration, a light diffusion control film having isotropic light diffusion characteristics can be obtained.

In addition, in constituting the laminate of the present invention, as an internal structure in the light diffusion control film, a plurality of plate-shaped regions having different refractive indices are alternately arranged in one direction along the film surface. Includes a louver structure it is desirable

With this configuration, a light-diffusion control film having an anisotropic light-diffusion characteristic can be obtained.

Further, another aspect of the present invention is a method for manufacturing a laminate described above, characterized by including the following steps (a) to (d).

(a) Step of preparing a composition for light diffusion control film containing a high refractive index active energy ray curing component and a low refractive index active energy ray curing component

(b) Step of forming a coating layer by applying the composition for a light diffusion control film in a film form to the step sheet

(c) a step of laminating an overlaminate film that satisfies the relational expression (1) on the exposed surface of the coating layer

(d) Step of irradiating active energy rays to the coated layer through an overlaminate film while moving the coated layer

That is, according to the manufacturing method of the laminate of the present invention, the overlaminate film has a non-uniformity in the retardation Re measured along a predetermined direction within its surface within a predetermined range. Then, the coating layer made of the composition for light diffusion control film is cured (photocured) by irradiation with active energy rays in the state where the overlaminate film is laminated. As a result, it is possible to obtain a laminate of the light-diffusion control film and the overlaminate film having uniform light-diffusion characteristics regardless of locations in the film surface.

1(a) to (b) are diagrams provided for explaining the outline of the laminate of the present invention.
2(a) to (b) are diagrams provided for explaining the outline of a light diffusion control film having a column structure within the film.
3(a) to (b) are views provided to explain the incident angle dependence and isotropic light diffusion in the light diffusion control film having a columnar structure within the film.
4(a) to (d) are views provided to explain aspects of the internal structure of the light diffusion control film in the present invention.
5(a) to (c) are diagrams provided for explaining the manufacturing method of the laminate of the present invention.
Fig. 6 is a diagram provided to explain the irradiation angle of active energy rays.
Fig. 7 is a diagram provided to show the relationship between the position of the overlaminate film in the short direction and the phase difference Re in Example 1 and Comparative Example 1;
8(a) to (c) are views provided to show cross-sectional photographs of the light diffusion control film in Examples 1 and 2 and Comparative Example 1.
9(a) to (b) are diagrams provided to show the relationship between the angle of incidence of reference light and the angle-change haze with respect to the light diffusion control film in Examples 1 and 2 and Comparative Example 1.
10(a) to (b) are provided to show the relationship between the position in the short direction of the light diffusion control film in Examples 1 and 2 and Comparative Example 1 and the straight transmitted light intensity PT. drawing.

[First Embodiment]

As shown in Fig. 1 (a), in the first embodiment of the present invention, an overlaminate film 4 is provided on at least one surface of a light diffusion control film 10 derived from a composition for a light diffusion control film. It is the laminated body 100 made into the laminated state.

The light diffusion control film 10 has a plurality of high refractive index regions 12 in the low refractive index region 14, and the high refractive index regions 12 have an internal structure 20 extending in the thickness direction. While having, within the laminated surface of the laminate 100, the moving direction when forming the light diffusion control film 10 is the long direction, and the direction perpendicular to the long direction is the short direction, and overlaminate When the maximum value of the retardation Re (nm) measured along the short direction of the film 4 is set to Re _max and the minimum value is set to Re _min , the following relational expression (1) is satisfied.

(Re _max -Re _min )/(Re _max +Re _min )×100<35 (%) (1)

That is, as the laminate 100 formed by laminating the overlaminate film 4 on at least one surface of the light diffusion control film 10, the light diffusion control film 10 is a high refractive index curing component (high refractive index active energy ray curing component) and a cured product of a composition for a light diffusion controlling film containing a low refractive index curing component (low refractive index active energy ray curing component).

And, in the light diffusion control film as a cured product, while having an internal structure 20 provided with a plurality of regions 12 having a relatively high refractive index in the region 14 having a relatively low refractive index, in FIG. As shown in (b), the moving direction MD of the coating layer 1 derived from the composition for light diffusion control film at the time of photocuring is the long direction LD and the laminated surface of the layered product 100. The direction perpendicular to the long direction LD is the short direction SD, and the maximum value of the retardation Re (nm) measured along the short direction SD of the overlaminate film 4 is Re _max , and the minimum value is Re _min It is a laminate 100 characterized in that it satisfies the above relational expression (1) in the case of

EMBODIMENT OF THE INVENTION Hereinafter, the 1st Embodiment of this invention is specifically described with reference to appropriate drawings.

However, the composition for light diffusion control films and its curing mode will be described in the second embodiment.

1. Over Laminate Film

As the overlaminate film in the present invention is shown in Fig. 1(b), the moving direction MD of the coating layer 1 derived from the composition for a light diffusion control film is photocured. In the long direction LD, the direction perpendicular to the long direction LD within the laminated surface of the laminate is the short direction SD, and the maximum value of the phase difference Re (°) measured along the short direction SD of the overlaminate film 4 When is set to Re _max and the minimum value is set to Re _min , the following relational expression (1) is satisfied.

(Re _max -Re _min )/(Re _max +Re _min )×100<35 (%) (1)

The reason for this is that when the nonuniformity value of retardation Re represented by the left side of relational expression (1) becomes a value of 35% or more, the internal structure in the light diffusion control film cured through the overlaminate film is formed at the location within the film surface. Because it changes too much every time. Therefore, it is because it becomes difficult to maintain the uniformity of light diffusion characteristics within the film surface.

That is, the upper limit of the nonuniformity of the phase difference Re represented by the left side of relational expression (1) is more preferably set to a value of 30% or less, more preferably set to a value of 25% or less, and particularly set to a value of 10% or less. desirable.

In addition, the smaller the non-uniformity value of the phase difference Re represented by the left side of the relational expression (1) is, the better it is, but if the value is excessively small, the range of material selection is excessively limited.

Therefore, the lower limit of the unevenness of the phase difference Re represented by the left side of relational expression (1) is preferably a value of 0.1% or more, more preferably a value of 0.5% or more, and more preferably a value of 1% or more.

In addition, in calculating the non-uniformity of retardation Re, it is preferable to measure retardation Re at 5 to 100 locations at equal intervals along the short direction SD of the overlaminated film (the same applies to the median value of retardation Re described later).

1(b), the long direction LD and short direction SD of the overlaminate film coincide with the long direction LD and short direction SD of the laminate, and the light diffusion control film constituting the laminate and It also coincides with the long direction LD and the short direction SD of the process sheet.

In addition, although phase difference Re can be adjusted by the stretching process of a film, it is especially preferable to adjust by biaxial stretching.

Here, the relationship between the unevenness of the phase difference Re in the overlaminate film and the uniformity in the light-diffusion characteristics of the light-diffusion control film will be briefly described.

That is, it is considered that there is a close relationship between the vibration direction of the active energy ray to be irradiated and the refractive index distribution structure to be formed. In addition, when the active energy ray is irradiated onto the overlaminate film, vibrations in the long direction LD and the short direction SD of the overlaminate film are affected differently by the retardation of the overlaminate film. And it is estimated that the shift|offset|difference which occurred changes the vibration direction of an active energy ray.

As a result, it is estimated that the light-diffusion property of the light-diffusion control film formed under the overlaminate film is greatly influenced by the retardation Re of the overlaminate film. For this reason, it is estimated that if the phase difference Re becomes non-uniform in the short direction SD, the light diffusion characteristics also become non-uniform correspondingly.

In addition, it is preferable to set the median value of the retardation Re of the overlaminated film to a value within the range of 1000 to 3000 nm.

The reason for this is that when the median value of retardation Re is less than 1000 nm, it is a film with excessively low retardation Re, and therefore material selection may be difficult.

On the other hand, when the median value of retardation Re becomes a value exceeding 3000 nm, it is because it is a film with excessively high retardation Re, and therefore material selection may become difficult.

Therefore, it is more preferable to set the lower limit of the median value of the phase difference Re to a value of 1100 nm or more, and more preferably to a value of 1200 nm or more.

Further, the upper limit of the median value of the retardation Re is more preferably set to a value of 2800 nm or less, and further preferably a value of 2900 nm or less.

In addition, it is preferable to set the arithmetic average roughness (Ra) of the overlaminate film on the surface on the active energy ray irradiation side to a value within the range of 1 to 200 nm.

When such Ra becomes a value of less than 1 nm, at the time of unwinding an overlaminate film, the said films may adhere to each other and vibration at the time of peeling may become large. For this reason, there is a possibility that the vibration is conducted to the active energy ray irradiated portion and the degree of formation of the internal structure of the light diffusion control film is reduced.

On the other hand, when Ra exceeds 200 nm, diffusion of active energy rays occurs because the surface shape is too large, and structure formation may be hindered in some cases.

Therefore, it is more preferable to set the lower limit of the arithmetic average roughness (Ra) of the overlaminate film to a value of 5 nm or more, and more preferably to a value of 10 nm or more.

Further, the upper limit of the arithmetic mean roughness (Ra) of the overlaminated film is more preferably 100 nm or less, further preferably 40 nm or less, and particularly preferably 30 nm or less.

In addition, arithmetic mean roughness (Ra) as one of the surface roughnesses can be measured in accordance with JIS B 0601:2001, but can also be measured in accordance with ANSI B46.1.

Further, it is preferable to set the maximum peak height (Rp) of the overlaminate film to a value within the range of 20 to 5000 nm.

The reason for this is that when such Rp becomes a value of less than 20 nm, at the time of unwinding an overlaminate film, the said films adhere closely, and vibration at the time of peeling may become large. For this reason, there is a possibility that the vibration is conducted to the active energy ray irradiated portion and the degree of formation of the internal structure of the light diffusion control film is reduced. On the other hand, when Rp is a value exceeding 5000 nm, the surface shape is too large, so that diffusion of active energy rays occurs and structure formation may be hindered in some cases.

Therefore, the lower limit of the maximum peak height (Rp) of the overlaminate film is more preferably set to a value of 50 nm or more, more preferably set to a value of 100 nm or more, and particularly preferably set to 300 nm or more.

Further, the upper limit of the maximum peak height (Rp) of the overlaminate film is more preferably 2000 nm or less, more preferably 1000 nm or less, and particularly preferably 600 nm or less.

In addition, the maximum peak height (Rp) as one of the surface roughness can be measured in accordance with JIS B 0601:2001, but can also be measured in accordance with ANSI B46.1.

Moreover, it is preferable to set the haze of the overlaminate film to a value within the range of 1 to 25%.

The reason for this is that when the haze becomes a value of less than 1%, at the time of unwinding the overlaminate film, the films concerned adhere to each other, and vibration at the time of peeling may become large. For this reason, there is a possibility that the vibration is conducted to the active energy ray irradiated portion and the degree of formation of the internal structure of the light diffusion control film is reduced.

On the other hand, if the haze exceeds 25%, diffusion of active energy rays occurs because the surface shape is too large, and structure formation may be hindered in some cases.

Therefore, it is more preferable to set the lower limit of the haze of the overlaminated film to a value of 3% or more, and it is more preferable to set it to a value of 5% or more.

Further, it is more preferable to set the upper limit of the haze of the overlaminated film to a value of 20% or less, and even more preferably to a value of 15% or less.

Moreover, it is preferable to set the total light transmittance of the overlaminate film to a value within the range of 70 to 97%.

The reason for this is that when the total light transmittance is less than 70%, the active energy ray transmittance is excessively reduced, making it difficult to efficiently form a predetermined internal structure in the light diffusion control film in some cases. On the other hand, when the total light transmittance exceeds 97%, the range of material selection is excessively limited.

Therefore, it is more preferable to set the lower limit of the total light transmittance of the overlaminated film to a value of 75% or more, and more preferably to a value of 80% or more.

Moreover, it is more preferable to set the upper limit of the total light transmittance of the overlaminated film to a value of 95% or less, and it is still more preferable to set it to a value of 93% or less.

In addition, the material of the overlaminate film is not particularly limited, but polyethylene terephthalate film, triacetyl cellulose film, cycloolefin polymer film, cyclic olefin film, ionomer film, polyethylene film, polyvinyl chloride film, polyvinylidene chloride Film, polyvinyl alcohol film, polypropylene film, polyester film, polycarbonate film, polystyrene film, polyacrylonitrile film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, ethylene-methacrylic acid copolymer A film, a nylon film, cellophane, etc. are mentioned, 1 type may be used independently among these, and you may use it in combination of 2 or more types.

The reason for this is that, with these materials, an overlaminated film that more stably satisfies relational expression (1) can be obtained.

Moreover, it is preferable to set it as a value within the range of 100-10000 mm in length in the short direction of an overlaminate film.

The reason for this is that when the length in the short direction becomes a value of less than 100 mm, the length of the light diffusion control film constituting the laminate also becomes a value of less than 100 mm in the short direction, and the light diffusion control film This is because there are cases in which a practically required size cannot be satisfied.

On the other hand, when the length in the short direction becomes a value exceeding 10000 mm, it is because irradiation of the active energy ray uniform in the width direction may become difficult.

Therefore, the lower limit of the length of the overlaminated film in the short direction is more preferably set to a value of 200 mm or more, further preferably set to a value of 300 mm or more, and particularly preferably set to a value of 600 mm or more.

Further, the upper limit of the length of the overlaminated film in the short direction is more preferably 8000 mm or less, more preferably 6000 mm or less, and particularly preferably 3000 mm or less. .

Moreover, it is preferable to make the film thickness of an overlaminate film into a value within the range of 5-5000 micrometers.

The reason for this is that, when the film thickness is less than 5 μm, handling becomes difficult and wrinkles may occur during bonding of the overlaminated film.

On the other hand, if the film thickness exceeds 5000 μm, handling becomes difficult and wrinkles may occur during transport of the overlaminated film.

Therefore, it is more preferable to set the lower limit of the film thickness of the overlaminate film to a value of 10 μm or more, and even more preferably to a value of 30 μm or more.

Further, the upper limit of the film thickness of the overlaminated film is more preferably set to a value of 1000 µm or less, further preferably set to a value of 400 µm or less, and still more preferably set to a value of 100 µm or less.

Moreover, you may provide a peeling layer by apply|coating a release agent, such as a silicone resin, to the surface of the side which contacts the light diffusion control film among both surfaces of an overlaminate film.

2. Light Diffusion Control Film

(1) Basic principle of light diffusion in light diffusion control film

First, as an example of the light diffusion control film in the present invention, an isotropic light diffusion control film 10a having a column structure 20a in the film and having an isotropic light diffusion property will be described using FIGS. 2 and 3. .

First, Fig. 2(a) shows a plan view of an isotropic light diffusion control film 10a having a columnar structure 20a in the film, and Fig. 2(b) shows an isotropic film shown in Fig. 2(a) The light diffusion control film 10a is cut in the vertical direction along the dotted line A-A, and a cross-sectional view of the isotropic light diffusion control film 10a when the cut surface is viewed from the direction of the arrow is shown.

3(a) shows an overall view of an isotropic light diffusion control film 10a having a columnar structure 20a in the film, and in FIG. 3(b), the isotropic light of FIG. 3(a) is shown. The degree of diffusion of the light diffused by the diffusion control film 10a (shape of spread of the diffused light) is shown.

As shown in the plan view of FIG. 2(a), the isotropic light diffusion control film 10a has a columnar structure 20a composed of columnar objects 12a having a relatively high refractive index and regions 14a having a relatively low refractive index. ) has

Further, as shown in the cross-sectional view of Fig. 2(b), inside the isotropic light diffusion control film 10a, there are columnar objects 12a having a relatively high refractive index and regions 14a having a relatively low refractive index. , a plurality of columnar objects 12a having relatively high refractive indices are arranged in an upright state so as to have a predetermined interval therebetween.

As a result, as shown in Fig. 3(a), it is estimated that the incident light whose incident angle θ1 is within the light-diffusion incident angle region is diffused by the isotropic light-diffusion control film 10a.

That is, as shown in (b) of FIG. 2 , the incident angle of incident light to the isotropic light diffusion control film 10a is a value within a predetermined angle range from parallel to the boundary surface 20a' of the columnar structure 20a. , That is, in the case of a value within the light diffusion incidence angle region, the incident light rays 52 and 54 exit along the film thickness direction while changing the direction from the inside of the columnar structure 12a having a relatively high refractive index. As a result, it is assumed that the traveling directions of the light on the light exit surface side are not the same.

As a result, it is estimated that when the incident angle is within the light diffusion incident angle region, the incident light is diffused by the isotropic light diffusion control film 10a and becomes diffused light 52', 54'.

On the other hand, when the angle of incidence of the incident light to the isotropic light diffusion control film 10a is out of the light diffusion incident angle region, as shown in FIG. 2 (b), the incident light 56 is the isotropic light diffusion control film ( It is presumed that the light passes as it is without being diffused by 10a) and becomes the transmitted light 56'.

According to the above basic principle, the isotropic light diffusion control film 10a provided with the columnar structure 20a exhibits incident angle dependence in transmission and diffusion of light, as shown in Fig. 3(a), for example. it becomes possible to do

Moreover, as shown in FIG.2(b), the isotropic light-diffusion control film 10a provided with the columnar structure 20a normally has "isotropy" as its light-diffusion characteristic.

Here, in the present invention, “isotropy” means, as shown in FIG. It means the property that the degree of diffusion of the light does not change depending on the direction within the same plane.

More specifically, as shown in Fig. 3(a), when incident light is diffused by the isotropic light diffusion control film 10a, the degree of diffusion of the diffused outgoing light is circular in a plane parallel to the film. do.

Further, as shown in (a) of FIG. 3 , the isotropic light-diffusion control film is on the light exit surface side when the incident angle θ1 of the incident light is included in the light-diffusion incident angle region, even if the incident angle θ1 is different from each other. Almost the same light diffusion can be made.

Therefore, it can be said that the isotropic light diffusion control film has a condensing action of concentrating light on a predetermined location.

In addition, the direction change of the incident light inside the columnar object 12a in the column structure is a step index type in which the direction changes in a zigzag manner in a straight line by total reflection as shown in FIG. A case where it becomes a gradient index type that changes direction in a curved line is also conceivable.

In addition, the internal structure of the light diffusion control film of the present invention is not limited to the columnar structure described above, as long as it includes a high refractive index region and a low refractive index region.

That is, in the technical field of the light diffusion control film, it is possible to form similarly in the light diffusion control film of the present invention as long as the internal structure can be formed by conventionally known phase separation.

For example, a louver structure 20b formed by alternately arranging a plurality of plate-like regions 12b and 14b having different refractive indices along an arbitrary direction along the film surface as shown in Fig. 4(a) may be used. .

Alternatively, as shown in Fig. 4(b), the columnar material may be a bent column structure 20c having a bent portion 16 at an intermediate point along the film thickness direction.

Alternatively, as shown in Fig. 4(c), a plurality of flaky objects 12d having a relatively high refractive index are arranged in a plurality of rows along an arbitrary direction along the film surface in a region 14d having a relatively low refractive index. It may be a predetermined internal structure 20d formed.

Alternatively, a combination of a louver structure 20b and a column structure 20a as shown in Fig. 4(d) may be used.

That is, although there are various types of internal structures known in the technical field of light diffusion control films, any of these internal structures may be used in the light diffusion control film in the present invention.

In any internal structure, the basic principle of light diffusion is the same as that of the columnar structure 20a.

However, due to the shape of each internal structure, a difference occurs in the shape of the spread of the diffused light.

For example, in the case of the louver structure 20b shown in Fig. 4(a), rod-shaped diffused light is generated in plan view with anisotropic light diffusion, and the bent column structure 20c shown in Fig. 4(b) In the case of , a part of light isotropically diffused above the bent portion generates diffused light further isotropically diffused below the bent portion.

In addition, in the case of the predetermined internal structure 20d shown in Fig. 4(c), since it is a hybrid type of the louver structure 20b and the column structure 20a, elliptical diffused light is generated in plan view, In the case of the combination of the louver structure 20b and the column structure 20a shown in Fig. 4(d), since part of the light diffused in the column structure 20a is further diffused in the louver structure 20b, when viewed in plan view It generates bullet-like diffused light.

(2) internal structure

The internal structure of the light diffusion control film in the present invention includes a high refractive index region and a low refractive index region, and is not particularly limited as long as light diffusion characteristics are obtained, and may be in various aspects such as a column structure or a louver structure. can do.

Hereinafter, although the column structure is demonstrated as an example, the contents about a column structure can be followed also about other internal structures, such as a louver structure.

As shown in (a) to (b) of FIG. 2 , the column structure 20a is an internal structure for isotropically diffusing incident light, and specifically, a plurality of relatively high refractive indices in a region having a relatively low refractive index. It is an internal structure formed by embedding the pillars of

(2)-1 refractive index

It is preferable that the difference between the refractive index of a region having a relatively low refractive index in the columnar structure and the refractive index of a plurality of columnar objects having a relatively high refractive index be a value of 0.01 or more.

The reason for this is that, when the difference in refractive index reaches a value of 0.01 or more, the angular region in which incident light is totally reflected within the column structure narrows, so that the incident angle dependence may be excessively reduced.

Therefore, it is more preferable to set the lower limit of this difference in refractive index to a value of 0.03 or more, and it is still more preferable to set it to a value of 0.1 or more.

Further, the larger the difference in refractive index, the better, but it is considered that about 0.3 is the upper limit from the viewpoint of selecting a material capable of forming a columnar structure.

(2)-2 maximum diameter

Further, in the columnar structure 20a as shown in (a) to (b) of Fig. 2, it is preferable to set the maximum diameter in the cross section of the columnar material to a value within the range of 0.1 to 15 µm.

The reason for this is that, when the maximum diameter is less than 0.1 µm, it may be difficult to exhibit light diffusion characteristics regardless of the incident angle of incident light. On the other hand, if the maximum diameter exceeds 15 μm, the amount of light traveling straight through the column structure may increase and the uniformity of the diffused light may decrease.

Therefore, in the column structure, the lower limit of this maximum value is more preferably set to a value of 0.5 μm or more, and more preferably set to a value of 1 μm or more.

In addition, in the columnar structure, the upper limit of this maximum value is more preferably set to a value of 10 μm or less, and more preferably set to a value of 5 μm or less.

In addition, the cross-sectional shape of the columnar object is not particularly limited, but it is preferable to set it as, for example, a circle, an ellipse, a polygon, a different shape, or the like.

In addition, the cross section of a columnar object means a cross section cut by a plane parallel to the film surface.

In addition, the maximum diameter, length, etc. of a columnar object can be measured by observing with an optical digital microscope.

In addition, the numerical range of the maximum diameter mentioned above applies similarly to the distance between columnar objects.

(2) -3 thickness

Further, it is preferable to set the thickness (length in the film thickness direction) of the columnar structure 20a as shown in Fig. 2(b) to a value within the range of 10 to 700 µm.

The reason for this is that, when the thickness is less than 10 μm, the amount of incident light traveling straight through the column structure increases, and it may be difficult to obtain a sufficient range of light diffusion characteristics. On the other hand, when such a thickness exceeds 700 μm, when the composition for light diffusion controlling film is irradiated with active energy rays to form a column structure, the direction of photopolymerization is diffused by the column structure formed in the initial stage. , It is because there are cases where it becomes difficult to form a desired columnar structure.

Therefore, it is more preferable to set the lower limit of the thickness of the column structure to a value of 30 μm or more, and it is more preferable to set it to a value of 50 μm or more.

Further, the upper limit of the thickness of the columnar structure is more preferably set to a value of 200 µm or less, and further preferably set to a value of 100 µm or less.

In addition, "the range of light diffusion characteristics" means the range of the angle of incidence and the range of spread of diffused light which show light diffusion characteristics.

(2)-4 angle of inclination

Further, as shown in Fig. 2(b), in the columnar structure 20a, it is preferable that the columnar objects 12a stand at a constant inclination angle with respect to the film thickness direction of the light diffusion control film.

The reason for this is that by making the inclination angle of the columnar objects constant, incident light can be reflected more stably in the column structure, and the incident angle dependence derived from the column structure can be further improved.

More specifically, in the column structure, it is preferable to set the angle of inclination of the columnar material with respect to the normal line of the film plane to a value within the range of 0 to 80 degrees.

The reason for this is that when such an angle of inclination becomes a value exceeding 80°, the absolute value of the angle of incidence of the active energy ray increases accordingly, so the ratio of reflection of the active energy ray at the interface between air and the coating layer increases. It is because it is necessary to irradiate an active energy ray of higher intensity in discarding and forming a columnar structure.

Therefore, it is more preferable to set the upper limit of this inclination angle to a value of 60° or less, and it is more preferable to set it to a value of 40° or less.

Incidentally, the angle of inclination is perpendicular to the film plane, and the normal line to the film surface, measured in a cross section when the film is cut by the plane that cuts the entire one columnar object into two along the axis, is formed by the top of the columnar object. It means the angle on the narrow side of the angle.

(3) film thickness

Moreover, it is preferable to make the film thickness of the light-diffusion control film in this invention into the value within the range of 10-700 micrometers.

The reason for this is that, when the film thickness of the light diffusion control film is less than 10 μm, the amount of incident light traveling straight through the column structure increases, making it difficult to exhibit the prescribed light diffusion characteristics in some cases. On the other hand, when the film thickness of the light diffusion control film exceeds 700 µm, when the composition for light diffusion control film is irradiated with active energy rays to form a column structure, photopolymerization proceeds by the initially formed column structure. This is because the direction diffuses, and it may become difficult to form a desired columnar structure. In addition, when applied to a display or the like, it is because blurring easily occurs in a displayed image in some cases.

Therefore, it is more preferable to set the lower limit of the film thickness of the light diffusion control film to a value of 30 μm or more, and it is more preferable to set it to a value of 50 μm or more.

On the other hand, it is more preferable to set the upper limit of the film thickness of the light diffusion control film to a value of 300 μm or less, and it is still more preferable to set it to a value of 100 μm or less.

(4) characteristics

Moreover, it relates to the characteristics of the light diffusion control film in the present invention, and it is preferable to set the width of the incident angle region of 70% or more haze to a value of 60° or more.

By restricting the width of the predetermined incident angle region in this way, the incident light is efficiently introduced and uniformly diffused, so that the brightness of the diffused light is improved in some cases.

Therefore, the width of the incident angle region having a haze of 70% or more is preferably set to a value of 80° or more, and more preferably set to a value of 100° or more.

Further, it relates to the characteristics of the light diffusion control film in the present invention, and the intensity of linearly transmitted light when the normal direction of the film surface is 0° and the incident light is irradiated at an angle of 60° in a direction further away from the incident angle region. It is preferable to set the median value of P.T to a value within the range of 0.1 to 99%.

As for this reason, when this median value becomes a value less than 0.1%, the transmittance|permeability of the whole film may deteriorate.

On the other hand, when this median value exceeds 99%, there is a case where the incident angle region is insufficient.

Therefore, it is more preferable to make the lower limit of this median value 1% or more, and it is more preferable to make it 5% or more.

Moreover, it is more preferable to make the upper limit of this median value into 50% or less, and it is still more preferable to make it 15% or less.

Incidentally, the linearly transmitted light intensity is expressed as a percentage by dividing the intensity of the outgoing light emitted at the same angle as the incident light by the intensity of the entire incident light.

Regarding the characteristics of the light diffusion control film in the present invention, it is preferable to set the unevenness of the linearly transmitted light intensity P.T to a value within the range of 0.1 to 3.8%.

As for this reason, when such a nonuniformity becomes a value less than 0.1%, control may become difficult.

On the other hand, when this nonuniformity becomes a value exceeding 3.8%, shading may arise in the light diffusion state.

Therefore, it is more preferable to make the lower limit of this non-uniformity into 1% or more, and it is still more preferable to make it 2% or more.

Moreover, it is more preferable to make the upper limit of this median value into 3.5% or less, and it is still more preferable to make it 2.8% or less.

3. Process sheet

As shown in Fig. 1 (a), the laminate 100 of the present invention is one side of the light diffusion control film 10, the opposite side to the side on which the overlaminate film 4 is laminated. You may laminate|stack the process sheet 2 on the surface of.

Thus, the light diffusion control film can be effectively protected by sandwiching both surfaces of the light diffusion control film with the overlaminate film and the process sheet.

Here, a process sheet is a sheet|seat to which the composition for light-diffusion control films is apply|coated when manufacturing a laminated body.

As such a process sheet, a normal release film can be used, and for example, a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, or a polyolefin film such as polypropylene or polyethylene, silicone What provided the release layer by apply|coating release agents, such as resin, is mentioned.

In addition, the film thickness of such a process sheet is preferably within a range of 20 to 150 µm.

[Second Embodiment]

2nd Embodiment of this invention is the manufacturing method of the laminated body as 1st embodiment, The manufacturing method of the laminated body characterized by including the following steps (a) - (d).

(a) Step of preparing a composition for light diffusion control film containing a high refractive index active energy ray curing component and a low refractive index active energy ray curing component

(b) Step of forming a coating layer by applying the composition for a light diffusion control film in a film form to the step sheet

(c) a step of laminating an overlaminate film that satisfies the relational expression (1) on the exposed surface of the coating layer

(d) Step of irradiating active energy rays to the coated layer through an overlaminate film while moving the coated layer

EMBODIMENT OF THE INVENTION Hereinafter, the 2nd Embodiment of this invention is concretely demonstrated with reference to drawings of enemies, focusing on different things from 1st Embodiment.

1. Process (a): Process of preparing composition for light diffusion control film

Step (a) is a step of preparing a predetermined composition for a light diffusion control film.

More specifically, it is a step of mixing the components (A) to (B) described below and other components as desired.

In addition, in mixing, although you may stir at room temperature as it is, from a viewpoint of improving uniformity, it is preferable to stir on heating conditions of 40-80 degreeC, for example, to make a uniform liquid mixture.

Moreover, it is also preferable to further add a diluting solvent so that it may become a desired viscosity suitable for coating.

(1) (A) component: high refractive index active energy ray curing component

The composition for a light diffusion control film according to the present invention is characterized by containing a high refractive index curing component (high refractive index active energy ray curing component) as component (A).

The reason for this is that, by including a high refractive index active energy component as component (A), there is a predetermined difference in polymerization rate between a low refractive index curing component (low refractive index active energy ray curing component) as component (B) described later. It is because it is possible to cure the component (A) and the component (B) while efficiently phase-separating by generating and suppressing uniform copolymerization of both components.

As a result, despite the uniform composition in the stage before curing, a predetermined internal structure such as a column structure or a louver structure is formed during curing, so that the light diffusion control film as a cured product obtained can efficiently diffuse incident light. Excellent light diffusion properties can be imparted.

(1)-1 refractive index

(A) It is preferable to make the refractive index of the high refractive index active energy ray hardening component as a value within the range of 1.5-1.65 as a component.

The reason for this is that when the refractive index of component (A) is less than 1.5, the difference between the refractive index of the low refractive index active energy ray curing component as component (B) becomes too small, and it is difficult to obtain effective light diffusion characteristics. because there is On the other hand, when the refractive index of component (A) exceeds 1.65, the difference from the refractive index of component (B) becomes large, but it is difficult to form even a seemingly compatible state with component (B) in some cases.

Therefore, it is more preferable to set the lower limit of the refractive index of component (A) to a value of 1.55 or more, and it is more preferable to set it to a value of 1.56 or more.

Moreover, it is more preferable to set the upper limit of the refractive index of component (A) to a value of 1.6 or less, and it is still more preferable to set it to a value of 1.59 or less.

In addition, the refractive index of the above-mentioned (A) component means the refractive index of (A) component before hardening by light irradiation.

In addition, a refractive index can be measured based on JISK0062:1992, for example.

(1) -2 types

The type of component (A) is not particularly limited, but is preferably a (meth)acrylic acid ester containing a plurality of aromatic rings.

This reason is that if it is such a compound, it can be photocured while phase-separating component (A) and component (B) more efficiently, and more superior light-diffusion characteristics can be obtained.

Examples of such compounds include biphenyl (meth)acrylate, naphthyl (meth)acrylate, anthracenyl (meth)acrylate, benzylphenyl (meth)acrylate, biphenyloxyalkyl (meth)acrylate, and (meth)acrylic acid. Naphthyloxyalkyl, (meth)acrylic acid anthracenyloxyalkyl, (meth)acrylic acid benzylphenyloxyalkyl, o-phenoxybenzyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, p-phenoxybenzyl (meth)acrylates, etc., or those in which some of these are substituted with halogen, alkyl, alkoxy, halogenated alkyl or the like, and the like are exemplified.

In addition, "(meth)acrylic acid" means both acrylic acid and methacrylic acid.

Moreover, as component (A), it is more preferable to include a compound containing a biphenyl ring, and in particular, it is more preferable to include a biphenyl compound represented by the following general formula (1).

(In general formula (1), R ¹ to ^{R 10} are each independently, at least one of R ¹ to R ¹⁰ is a substituent represented by the following general formula (2), the others are a hydrogen atom, a hydroxyl group, It is a substituent of any one of a carboxy group, an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyalkyl group, a carboxyalkyl group, and a halogen atom)

(In general formula (2), R ¹¹ is a hydrogen atom or a methyl group, carbon number n is an integer of 1 to 4, and repeating number m is an integer of 1 to 10)

The reason for this is that by including a biphenyl compound having a specific structure as component (A), a predetermined difference is generated in the polymerization rates of component (A) and component (B), and component (A) and ( It is because it is estimated that the compatibility with B) component is reduced to a predetermined range, and the copolymerizability of both components can be reduced.

In addition, by increasing the refractive index of a region having a relatively high refractive index derived from component (A), the difference from the refractive index of a region having a relatively low refractive index derived from component (B) can be more easily adjusted to a value greater than or equal to a predetermined value. can

Moreover, as a specific example of the biphenyl compound represented by General formula (1), the compound represented by the following formula (3) - (4) is mentioned preferably.

(2) (B) component: low refractive index active energy ray curing component

The composition for a light diffusion control film in the present invention is characterized by containing a low refractive index active energy ray curing component as component (B).

The reason for this is that by including the low refractive index active energy ray curing component as component (B), a predetermined difference is generated in the polymerization rate between the high refractive index active energy ray curing component as component (A) described above, It is because it can make it photocurable, carrying out phase-separation of (A) component and (B) component efficiently by suppressing that both components mutually copolymerize uniformly.

As a result, despite the uniform composition in the stage before photocuring, a predetermined internal structure such as a column structure or a louver structure is formed during photocuring, so that incident light is efficiently transmitted to the light diffusion control film as a cured product obtained. Excellent diffusible light diffusion characteristics can be imparted.

(2)-1 refractive index

(B) It is preferable to make the refractive index of the low refractive index active energy ray hardening component as a value within the range of 1.4-1.5 as a component.

The reason for this is that when the refractive index of component (B) is less than 1.4, the difference from the refractive index of component (A) becomes large, but the compatibility with component (A) is extremely deteriorated, and a predetermined internal structure is formed. Because it can be difficult to do. On the other hand, if the refractive index of component (B) exceeds 1.5, the difference between the refractive index of component (A) becomes too small, and it is sometimes difficult to obtain desired light diffusing properties.

Therefore, it is more preferable to set the lower limit of the refractive index of component (B) to a value of 1.45 or more, and it is further more preferable to set it to a value of 1.46 or more.

Moreover, it is more preferable to set the upper limit of the refractive index of component (B) to a value of 1.49 or less, and it is still more preferable to set it to a value of 1.48 or less.

In addition, the above-mentioned refractive index of component (B) means the refractive index of component (B) before hardening by light irradiation. And refractive index can be measured based on JISK0062:1992, for example as mentioned above.

Moreover, it is preferable to make the difference of the refractive index of the above-mentioned component (A) and the refractive index of component (B) a value of 0.01 or more.

The reason for this is that, when the difference in refractive index is less than 0.01, the angular range in which incident light is totally reflected within a predetermined internal structure narrows, so that the range of light diffusion characteristics may be excessively narrowed in some cases. On the other hand, if the difference in refractive index becomes an excessively large value, compatibility between component (A) and component (B) deteriorates too much, and it is sometimes difficult to form a predetermined internal structure.

Therefore, it is more preferable to set the lower limit of the difference between the refractive index of component (A) and the refractive index of component (B) to a value of 0.05 or more, and more preferably to a value of 0.1 or more.

Further, the upper limit of the difference between the refractive index of component (A) and the refractive index of component (B) is more preferably 0.5 or less, and still more preferably 0.2 or less.

In addition, the refractive index of (A) component and (B) component here means the refractive index of (A) component and (B) component before hardening by light irradiation.

(2) -2 types

In addition, the type of component (B) is not particularly limited, and examples thereof include urethane (meth)acrylate, a (meth)acrylic polymer having a (meth)acryloyl group in the side chain, and (meth)acryloyl group-containing Although a silicone resin, an unsaturated polyester resin, etc. are mentioned, it is especially preferable to set it as urethane (meth)acrylate.

This reason is that if it is urethane (meth)acrylate, component (A) and component (B) can be photocured while phase-separating more efficiently, and further superior light-diffusion characteristics can be obtained.

Moreover, (meth)acrylate means both an acrylate and a methacrylate.

Further, the urethane (meth)acrylate is (B1) a compound containing at least two isocyanate groups, (B2) a polyol compound, preferably a diol compound, particularly preferably a polyalkylene glycol, and (B3) a hydroxyalkyl ( It is formed from meth)acrylates.

Moreover, the oligomer which has a repeating unit of a urethane bond is also included in (B) component.

Among these, as the compound containing at least two isocyanate groups as component (B1), for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4- Aromatic polyisocyanates such as xylylene diisocyanate and methylenediphenyl 4,4'-diisocyanate (MDI), aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate alicyclic polyisocyanates such as the like, and their biuret form, isocyanurate form, and also adduct forms that are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil (For example, a xylylene diisocyanate-based trifunctional adduct); and the like.

Among the components forming urethane (meth)acrylate, examples of the polyalkylene glycol as component (B2) include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyhexylene glycol. Among these, polypropylene glycol is particularly preferred.

The reason for this is that polypropylene glycol, when curing the component (B), becomes a good soft segment in the cured product, effectively improving the handling properties and mounting properties of the resulting light diffusion control film. .

Moreover, the weight average molecular weight of (B) component can be mainly adjusted by the weight average molecular weight of component (B2). Here, the weight average molecular weight of component (B2) is usually 2,300 to 19,500, preferably 4,300 to 14,300, and particularly preferably 6,300 to 12,300.

Among the components forming urethane (meth)acrylate, examples of the hydroxyalkyl (meth)acrylate as component (B3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl ( meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc. can be heard

Further, from the viewpoint of reducing the polymerization rate of the obtained urethane (meth)acrylate and forming a predetermined internal structure more efficiently, it is more preferably hydroxyalkyl methacrylate, and 2-hydroxyethyl methacrylate is particularly preferred. Rate is more preferable.

(2)-3 Blending amount

Further, when the total amount of component (A) and component (B) is 100 parts by weight, the compounding ratio of component (A) and component (B) (component (A): component (B) (weight ratio)) is 20 : It is preferable to set it as a value within the range of 80-80:20.

That is, when the total amount of component (A) and component (B) is 100 parts by weight, it is preferable to set the blending ratio of component (B) to a value within the range of 20 to 80 parts by weight.

The reason for this is that when the blending ratio of component (B) is less than 20 parts by weight, the width of the region where the refractive index derived from component (A) is relatively high, and the refractive index derived from component (B) is relatively low. This is because it may become excessively large compared to the width of the region, making it difficult to obtain good light diffusion characteristics. On the other hand, when the blending ratio of component (B) exceeds 80 parts by weight, the proportion of component (A) relative to component (B) decreases, and the refractive index derived from component (A) is relatively high. This is because the width becomes too small compared to the width of the region where the refractive index derived from component (B) is relatively low, and it is sometimes difficult to obtain good light diffusion characteristics.

Therefore, when the total amount of component (A) and component (B) is 100 parts by weight, it is more preferable to set the lower limit of the blending ratio of component (B) to 40 parts by weight or more, and to a value of 55 parts by weight or more. It is more preferable to

Further, when the total amount of component (A) and component (B) is 100 parts by weight, the upper limit of the blending ratio of component (B) is more preferably 70 parts by weight or less, and 65 parts by weight or less It is more preferable to

(3) (C) component: photopolymerization initiator

Moreover, in the composition for light diffusion control films, it is preferable to contain a photopolymerization initiator as component (C).

This reason can be photocured while phase-separating the component (A) and the component (B) more efficiently when an active energy ray is irradiated to the composition for a light diffusion control film by containing a photopolymerization initiator, and further This is because excellent light diffusion characteristics can be obtained.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, and dimethylaminoaceto. Phenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxy Cyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy -2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenonedimethylketal, p-dimethylamine benzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane], etc., and one of these may be used alone; You may use it in combination of 2 or more types.

In addition, as a compounding quantity of component (C), it is preferable to set it as a value within the range of 0.2-20 weight part with respect to 100 weight part of total amounts of (A) component and (B) component.

The reason for this is that when the amount of the component (C) is less than 0.2 parts by weight, the starting point of polymerization is lowered, so that it may be difficult to sufficiently cure the composition for a light diffusion control film. On the other hand, when the amount of the component (C) exceeds 20 parts by weight, yellowing of the light diffusion control film and decrease in durability may easily occur.

Therefore, it is more preferable to set the lower limit of the blending amount of component (C) to a value of 0.5 parts by weight or more, and it is still more preferable to set it to a value of 1 part by weight or more.

Further, the upper limit of the blending amount of component (C) is more preferably 15 parts by weight or less, and still more preferably 10 parts by weight or less.

(4) other additives

Further, appropriate other additives may be blended within a range not impairing the effects of the present invention.

Examples of other additives include antioxidants, antistatic agents, polymerization accelerators, polymerization inhibitors, infrared absorbers, plasticizers, diluting solvents, and leveling agents.

In addition, the content of other additives is generally preferably set to a value within the range of 0.01 to 5 parts by weight with respect to the total amount (100 parts by weight) of component (A) and component (B).

In particular, it is preferable to incorporate a UV absorber as another additive.

The reason for this is that when an active energy ray is irradiated, an active energy ray of a predetermined wavelength can be selectively absorbed within a predetermined range by blending the ultraviolet absorber.

As a result, without inhibiting curing of the composition for a light diffusion control film, for example, as shown in Fig. 4(b), a predetermined internal structure formed inside the obtained light diffusion control film can be bent. because there is

Further, the ultraviolet absorber is preferably at least one selected from the group consisting of hydroxyphenyltriazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and hydroxybenzoate-based ultraviolet absorbers.

The reason for this is that since these ultraviolet absorbers can more clearly generate waviness in a predetermined internal structure, the range of light-diffusion characteristics in the obtained light-diffusion control film can be more effectively expanded.

That is, it is because it has been confirmed that waviness is generated with a small compounding amount as long as it is these ultraviolet absorbers having a peak at a location closer to the wavelength of 365 nm, which is the dominant wavelength of a high-pressure mercury lamp.

In addition, the blending amount of the ultraviolet absorber in the composition for light diffusion control film is less than 2 parts by weight (excluding 0 parts by weight) with respect to 100 parts by weight of the total amount of component (A) and component (B). It is desirable to do

The reason for this is that when the amount of the ultraviolet absorber is 2 parts by weight or more, curing of the composition for light diffusion controlling film is inhibited, causing shrinkage wrinkles to occur on the surface of the film or not curing at all. On the other hand, if the compounding amount of the ultraviolet absorber is excessively small, it is because it may be difficult to generate sufficient waviness with respect to the internal structure formed inside the light diffusion control film.

Therefore, the lower limit of the blending amount of the ultraviolet absorber is more preferably set to a value of 0.01 part by weight or more, and more preferably set to a value of 0.02 part by weight or more with respect to 100 parts by weight of the total amount of component (A) and component (B). .

The upper limit of the blending amount of the ultraviolet absorber is more preferably 1.5 parts by weight or less, and more preferably 1 part by weight or less, based on 100 parts by weight of the total amount of component (A) and component (B). desirable.

2. Process (b): Application process

Step (b) is a step of applying the composition for a light diffusion control film in a film form to the process sheet 2 to form the application layer 1, as shown in Fig. 5(a).

As such a process sheet, as described in the first embodiment, a normal release film can be used.

In addition, as a method of applying the composition for a light-diffusion film onto the process sheet, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like can be used.

In addition, it is preferable to set the thickness of the coating layer at this time to a value within the range of 10 to 700 µm.

3. Process (c): Laminate process

Step (c) is a step of laminating the overlaminate film 4 that satisfies relational expression (1) on the exposed surface of the application layer 1, as shown in Fig. 5(b).

That is, this is a step of laminating the uncured coating layer 1 while maintaining a gap between the process sheet 2 and the overlaminate film 4 so as not to crush it.

4. Process (d): Active energy ray irradiation process

As shown in Fig. 5(c), in the step (d), parallel light 60 is transmitted to the coated layer 1 via the overlaminate film 4 while moving the coated layer 1. This is a step of irradiating phosphorus active energy rays to form a predetermined internal structure such as a column structure or a louver structure in the film to obtain the light diffusion control film 10 .

Hereinafter, as an example, a case where a column structure is formed will be described.

That is, as shown in Fig. 5(c), the parallel light 60 having a high degree of parallelism is irradiated to the coating layer 1 formed on the process sheet 2.

Here, the parallel light means substantially parallel light in which the traveling direction of the light does not spread even when viewed from any direction.

More specifically, for example, as shown in FIG. 5(c) , the irradiated light 70 from the point light source 102 can be converted into parallel light 60 by the lens 104 .

Moreover, it is preferable to make the parallelism of irradiated light into a value of 10 degrees or less.

The reason for this is that a column structure can be efficiently and stably formed by setting the parallelism of the irradiated light to a value within this range.

Therefore, it is more preferable to set the parallelism of the irradiated light to a value of 5° or less, and even more preferably to a value of 2° or less.

In addition, as the irradiation angle of irradiation light, as shown in FIG. 6, the irradiation angle θx when the angle of the normal to the surface of the coating layer 1 is 0° is usually within the range of -80 to 80°. It is preferable to set it as a value.

The reason for this is that if the irradiation angle is outside the range of -80 to 80°, the effect of reflection or the like on the surface of the coating layer 1 increases, making it sometimes difficult to sufficiently form a columnar structure.

In addition, the arrow MD in FIG. 6 points out the movement direction of an application layer.

Moreover, it is preferable to use an ultraviolet-ray as irradiation light which is an active energy ray.

This is because, in the case of an electron beam, the polymerization rate is very high, so that component (A) and component (B) cannot sufficiently phase separate in the course of polymerization, making it difficult to form a columnar structure in some cases.

On the other hand, when compared to visible light, etc., since there are more variations of ultraviolet curable resins curable by irradiation with ultraviolet rays and usable photopolymerization initiators, it is possible to broaden the range of selection of components (A) and (B). Because.

Moreover, as an irradiation condition in the case of using an ultraviolet ray as an active energy ray, it is preferable to make the peak illumination intensity in the surface of a coating layer into the value within the range of 0.1-10 mW/cm<2>.

The reason for this is that it may be difficult to clearly form a columnar structure when such a peak illuminance becomes a value of less than 0.1 mW/cm 2 . On the other hand, it is because when such a peak illuminance becomes a value exceeding 10 mW/cm<2>, it is estimated that a hardening speed becomes too fast, and a columnar structure may not be formed effectively.

Therefore, it is more preferable to set the lower limit of the peak illuminance on the surface of the coating layer to a value of 0.3 mW/cm 2 or more, and it is still more preferable to set it to a value of 0.5 mW/cm 2 or more.

Moreover, it is more preferable to set the upper limit of the peak illuminance on the surface of the coating layer to a value of 8 mW/cm 2 or less, and it is still more preferable to set it to a value of 6 mW/cm 2 or less.

Moreover, it is preferable to make the integrated light quantity on the surface of the coating layer in the case where an ultraviolet ray is used as an active energy ray into the value within the range of 5-200 mJ/cm<2>.

The reason for this is that when the amount of integrated light is less than 5 mJ/cm 2 , it may be difficult to sufficiently extend the column structure from the top to the bottom. On the other hand, it is because coloring may arise in the light-diffusion control film obtained when this integrated light amount becomes a value exceeding 200 mJ/cm<2>.

Therefore, it is more preferable to set the lower limit of the amount of integrated light on the surface of the coating layer to a value of 7 mJ/cm 2 or more, and even more preferably to a value of 10 mJ/cm 2 or more.

Moreover, it is more preferable to set the upper limit of the amount of integrated light on the surface of the coating layer to a value of 150 mJ/cm 2 or less, and it is still more preferable to set it to a value of 100 mJ/cm 2 or less.

In addition, from the viewpoint of stably forming a column structure while maintaining mass productivity, when irradiating ultraviolet rays or the like as active energy rays, the coating layer formed on the process sheet is moved at a speed within the range of 0.1 to 10 m/min. It is desirable to do

In particular, it is more preferable to move at a speed of 0.2 m/min or more, and more preferably to move at a speed of 3 m/min or less.

In the present invention, the internal structure formed in the light diffusion control film formed by curing the composition for light diffusion control film is not limited to the columnar structure described above, as long as it includes a high refractive index region and a low refractive index region. .

For example, in the case of forming the louver structure 20b shown in Fig. 4(a), the application layer 1 formed on the process sheet 2 is substantially substantially What is necessary is just to irradiate the light which is parallel light, and looks like non-parallel random light when viewed from another direction.

In addition, in the case of forming the predetermined internal structure 20d shown in FIG. 4(c), with respect to the coating layer 1 formed on the process sheet 2, when viewed from one direction, substantially parallel light, When viewed from another direction, light adjusted to a certain degree of parallelism may be irradiated instead of completely random light.

(Example)

Hereinafter, the present invention will be described in more detail by examples. However, the present invention is not limited to these descriptions.

[Example 1]

1. Preparation of overlaminate film

As the overlaminate film, a biaxially stretched polyethylene terephthalate film roll (hereinafter sometimes referred to as "film A") having a thickness of 38 µm and a length of 1000 mm in the short direction (width direction) was prepared.

(1) Measurement of phase difference Re

The phase difference Re of the prepared overlaminate film was measured.

That is, an arbitrary location in the elongated direction of the prepared overlaminate film was identified as a measurement location.

Next, along the short direction of 1000 mm in the specific measurement location, 20 locations at every 50 mm were used as measurement points, and phase difference Re ( nm) was measured. The obtained results are shown in characteristic curve A in FIG. 7 .

This FIG. 7 is a short direction position-phase difference Re chart in which the position (mm) of the overlaminated film in the short direction of the overlaminate film is taken as the horizontal axis, and the phase difference Re (nm) is taken as the vertical axis.

Moreover, the median value (nm) of phase difference Re and the nonuniformity ((Re _max -Re _min )/(Re _max +Re _min ) x 100) (%) represented by Formula (1) were computed from the obtained measured value. The obtained results are shown in Table 1.

(2) surface roughness Rp and Ra

In addition, the arithmetic average roughness (Ra) and maximum peak height (Rp) of the prepared overlaminate film were measured.

That is, while measuring the arithmetic mean roughness (Ra) (nm) of the prepared overlaminate film using a surface shape measuring device WYKO NT110 (ANSI B46.1 standard) manufactured by Veeco, the maximum peak height (Rp) (nm) ) was measured. The obtained results are shown in Table 1.

(3) Measurement of haze and total light transmittance

In addition, the haze of the prepared overlaminate film was measured.

That is, haze (%) and total light transmittance (%) of the prepared overlaminate film were measured using a haze meter NDH-5000 manufactured by Nippon Denshoku Kogyo Co., Ltd. The obtained results are shown in Table 1.

2. Synthesis of low refractive index active energy ray curing component

In a container, 2 moles of isophorone diisocyanate (IPDI) as component (B1) and 2-hydroxyethyl as component (B3) with respect to 1 mol of polypropylene glycol (PPG) having a weight average molecular weight of 9200 as component (B2). After accommodating 2 mol of methacrylates (HEMA), it was made to react according to the usual method, and the polyether urethane methacrylate of weight average molecular weight 9900 as component (B) was obtained.

In addition, the weight average molecular weight of polypropylene glycol and polyether urethane methacrylate is a polystyrene conversion value measured according to the following conditions by gel permeation chromatography (GPC).

・GPC measuring device: Tosoh Co., Ltd., HLC-8020

・GPC column: manufactured by Tosoh Co., Ltd. (hereinafter, described in order of passing)

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

・Measurement solvent: tetrahydrofuran

・Measurement temperature: 40℃

3. Preparation of composition for light diffusion control film

Next, o-phenylphenoxyethoxyethyl acrylate having a molecular weight of 268 represented by the above formula (3) as component (A) (manufactured by Shin-Nakamura Chemical Co., Ltd., NK Ester A-LEN-10) 62.5 weight 37.5 parts by weight of polyether urethane methacrylate having a weight average molecular weight of 9900 as part and synthesized (B) component, 2- as component (C) with respect to 100 parts by weight of the total amount of component (A) and component (B) After adding 1.25 parts by weight of hydroxy-2-methyl-1-phenyl-propan-1-one, heating and mixing was performed on 80 degreeC conditions, and the composition for light diffusion control films was obtained.

In addition, the refractive indices of component (A) and component (B) were measured in accordance with JIS K0062 using an Abbe refractometer (manufactured by Atago Co., Ltd., Abbe refractometer DR-M2, Na light source, wavelength 589 nm) and found to be 1.58, respectively. and 1.46.

4. Application process

Next, the obtained composition for a light diffusion control film was applied to the peeling treated surface while pulling out a transparent polyethylene terephthalate film roll as a process sheet subjected to peeling treatment having a length of 1000 mm in the short direction, and applying a coating layer having a film thickness of 60 µm. has formed

5. Laminate process

Next, the prepared overlaminate film was laminated on the exposed side of the coating layer by roll-to-roll.

Next, as shown in Fig. 5(c), using an ultraviolet spot collimated light source (manufactured by Jatech Co., Ltd.) in which the central ray parallelism was controlled to within ±3°, parallel light having a parallelism of 2° or less was emitted. The coating layer was irradiated so that the irradiation angle θx shown in 6 was approximately 10°.

The peak illuminance at that time was 2.00 mW/cm 2 , the integrated light amount was 53.13 mJ/cm 2 , the lamp height was 1480 mm, and the moving speed of the coating layer was 1.0 m/min.

In addition, the above-mentioned peak illuminance and integrated light intensity were measured by installing a UV METER (manufactured by Eye Graphics Co., Ltd., UV integrating irradiation meter UVPF-A1) equipped with a photoreceptor at the position of the coating layer.

In addition, the film thickness of the light-diffusion control film was measured using the static-pressure thickness measuring instrument (Tec-Lock PG-02J by Takara Sesakusho Co., Ltd.).

Fig. 8(a) shows a cross-sectional photograph obtained by cutting the obtained light diffusion control film having a columnar structure into a plane parallel to the moving direction of the coating layer and orthogonal to the film plane.

In addition, the length of the column structure in the film thickness direction was 60 μm, and the inclination angle thereof was 7°.

In addition, cutting of the light diffusion control film was performed using a razor, and photographing of the cross section was performed by reflection observation using a digital microscope VHX-1000 manufactured by Keyence.

6. Evaluation

(1) Measurement of angle change haze

The angular haze of the obtained light diffusion control film was measured.

That is, a strip-shaped test piece (120 mm width) was cut out from an arbitrary location of the obtained process sheet/light diffusion control film/overlaminated film laminate along the elongated direction, manufactured by Toyoseki Sesakujo Co., Ltd. , Angle change haze (%) was measured using Haze Guard Plus.

At this time, the distance between the integrating sphere opening and the light diffusion control film was 62 mm, and the incident point of the reference light was the center point in the short direction of the light diffusion control film in the test piece.

In addition, as shown in (a) of FIG. 9, while the reference light entered from the process sheet|seat side of a test piece, the incident angle of the reference light was changed along the long direction of the light diffusion control film, and the measurement was performed. The obtained result is shown in the characteristic curve A of FIG.9(b).

9(b) is an incident angle-variation haze chart in which the incident angle (°) of the reference light is taken on the horizontal axis and the angle change haze (%) is taken on the vertical axis. Moreover, the width|variety of the incident angle area|region of 70% or more of haze was computed from FIG.9(b), and it showed in Table 1.

Therefore, from the characteristic curve A, the property that the light diffusion degree differs depending on the incident angle, that is, the incident angle dependence can be confirmed (characteristic curve B: Example 2, characteristic curve C: Comparative Example 1 as well).

(2) Measurement of straight transmitted light intensity P.T.

The straight transmission intensity of the obtained light diffusion control film was measured.

That is, along 1000 mm in the short direction in the test piece similar to that used in the measurement of the angular haze, 20 points were set at every 50 mm as measurement points, using a variegated colorimeter VC-2 manufactured by Sugashi Kenki Co., Ltd. Straight transmitted light intensity P.T (%) was measured.

At this time, as shown in (a) of FIG. 10 , light was incident from a direction inclined at 60° in a direction opposite to the inclined direction of the columnar objects in the light diffusion control film to the process sheet side of the test piece and measured. . The obtained result is shown in the characteristic curve A of FIG. 10(b).

10(b) is a short direction position-straight transmitted light intensity chart in which the position (mm) of the light diffusion control film in the short direction is taken as the horizontal axis, and the straight transmitted light intensity (%) is taken as the vertical axis.

Further, from the obtained measurement values, the median value (%) of straight transmitted light intensity PT and the unevenness ((PT _max -PT _min )/(PT _max +PT _min ) × 100) (%) represented by formula (1) were calculated. . The obtained results are shown in Table 1.

[Example 2]

In Example 2, as an overlaminate film, a biaxially stretched polyethylene terephthalate film roll having a thickness of 38 µm and a length of 1000 mm in the short direction having the phase difference Re and surface roughness shown in Table 1 (hereinafter referred to as film B) Except for using), a laminate was prepared and evaluated in the same manner as in Example 1.

The obtained results are shown in Table 1, the characteristic curve B in FIG. 8(b) and FIG. 9(b) and the characteristic curve B in FIG. 10(b).

[Comparative Example 1]

In Comparative Example 1, as an overlaminate film, a biaxially stretched polyethylene terephthalate film roll having a thickness of 75 mm and a length of 1000 mm in the short direction having the phase difference Re and surface roughness shown in Table 1 (hereinafter referred to as "film C") Except for using), a laminate was prepared and evaluated in the same manner as in Example 1.

The obtained results are shown in Table 1, the characteristic curve C in Fig. 8 (b) and Fig. 9 (b) and the characteristic curve C in Fig. 10 (b).

[Table 1]

As described above, according to the present invention, when the non-uniformity of the retardation measured along a predetermined direction within the overlaminated film surface is set to a value within a predetermined range, the internal structure unformed region does not occur or occurs Even in this case, the internal structure can be uniformly formed.

As a result, it became possible to obtain a light-diffusion control film having uniform light-diffusion characteristics regardless of locations in the film surface.

Accordingly, the light diffusion control film obtained according to the present invention is expected to significantly contribute to high quality of liquid crystal display devices, projection screens, and the like.

1: coating layer 2: substrate
2': other substrate 10: anisotropic light diffusing adhesive sheet
10a: Isotropic light diffusion control film 10b to 10d: light diffusion control film
12, 12b to 12d: regions with relatively high refractive index (including plate-like regions with relatively high refractive index)
12a: columnar material with relatively high refractive index
14, 14a to 14d: regions with relatively low refractive index (including plate-like regions with relatively low refractive index)
16: bending part 20: internal structure
20a': boundary surface 20a: columnar structure
20b: louver structure 20c: bent column structure
20d: predetermined internal structure 60: collimated light
70: radiation from a point light source 100: laminate
102: point light source 104: lens

Claims (7)

A laminate in which an overlaminate film is laminated on at least one surface of a light diffusion control film derived from a composition for a light diffusion control film,
The light diffusion control film has a plurality of high refractive index regions in a low refractive index region, and the high refractive index regions have an internal structure extending in the thickness direction,
In the lamination surface of the laminate, the moving direction when forming the light diffusion control film is a long direction, and a direction perpendicular to the long direction is a short direction, and
When the maximum value of the retardation Re (nm) measured along the short direction of the overlaminate film is set to Re _max and the minimum value is set to Re _min , the following relational expression (1) is satisfied,
A laminate characterized in that the median value of the retardation Re of the overlaminate film is a value within a range of 1000 to 3000 nm.
(Re _max -Re _min )/(Re _max +Re _min )×100<35 (%) (1) According to claim 1,
A laminate characterized in that the length of the overlaminate film in the short direction is set to a value within a range of 100 to 10000 mm. delete According to claim 1 or 2,
A laminate characterized in that the film thickness of the overlaminate film is set to a value within the range of 5 to 5000 μm. According to claim 1 or 2,
The internal structure of the light diffusion control film includes a column structure formed by standing a plurality of columnar objects having a relatively high refractive index in a film thickness direction in a region having a relatively low refractive index. Laminate characterized in that to do. According to claim 1 or 2,
A laminate characterized by including a louver structure formed by arranging a plurality of plate-shaped regions having different refractive indices alternately in one direction along a film surface as an internal structure in the light diffusion control film. As a manufacturing method of the laminate according to claim 1 or 2,
A method for producing a laminate comprising the following steps (a) to (d).
(a) Step of preparing a composition for light diffusion control film containing a high refractive index active energy ray curing component and a low refractive index active energy ray curing component
(b) a step of applying the composition for a light diffusion control film in a film form to a step sheet to form a coating layer
(c) a step of laminating an overlaminate film satisfying the relational expression (1) on the exposed surface of the coating layer
(d) Step of irradiating active energy rays to the coated layer through the overlaminate film while moving the coated layer

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