JP7369536B2 - Laminated sheet roll - Google Patents

Description

The present invention relates to a roll body of a laminated sheet provided with a light diffusion control film that can diffuse or transmit incident light depending on the incident angle.

In the optical technology field to which liquid crystal display devices, organic light emitting devices, etc. belong, the use of light diffusion control films that can strongly diffuse incident light from a specific angle range in a specific direction is being considered.

An example of such a light diffusion control film is one that has an internal structure in which a plurality of regions with a relatively high refractive index are provided in a region with a relatively low refractive index. More specifically, a light diffusion control film having a louver structure in which a plurality of plate-like regions with different refractive indexes are arranged alternately along an arbitrary direction along the film surface, and a light diffusion control film with a relative refractive index. There are light diffusion control films and the like that have a column structure in which a plurality of columnar objects having a relatively high refractive index stand in a low region.

As the above-mentioned light diffusion control film, Patent Document 1 describes a film containing a predetermined urethane (meth)acrylate compound, a predetermined (meth)acrylate compound having an aromatic skeleton, and a predetermined photopolymerization initiator. A light diffusion control film obtained by curing a resin composition for a light diffusion control film is disclosed.

Patent No. 6414883

By the way, light diffusion control films have a problem in that they tend to be dented during manufacturing, transportation, storage, and the like. In particular, when transporting, storing, etc., the light diffusion control film is rolled up into a roll, foreign matter is likely to get caught between the light diffusion control films, and as a result, dents are likely to occur. Become. In particular, roll bodies may be stored for a long period of time with foreign matter pressed against the light diffusion control film, which may leave strong dents.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a roll body of a laminated sheet that can suppress the occurrence of dents in a light diffusion control film.

In order to achieve the above object, firstly, the present invention provides a first film and a region having a relatively low refractive index in the film, which is laminated on one side of the first film, and has a relatively low refractive index. Winding up a laminated sheet comprising a light diffusion control film having an internal structure with a plurality of regions with high heights, and a second film laminated on the side of the light diffusion control film opposite to the first film. Provided is a roll body of a laminated sheet, characterized in that the thickness of at least one of the first film and the second film is 45 μm or more (Invention 1).

In the roll body of the laminated sheet according to the above invention (Invention 1), at least one of the first film and the second film laminated on the light diffusion control film has the above-mentioned thickness, so that foreign matter is not caught in the roll body. Even if this occurs, it is possible to satisfactorily suppress the occurrence of dents on the light diffusion control film.

In the above invention (invention 1), it is preferable that an adhesive layer is provided between the light diffusion control film and the second film (invention 2).

In the above invention (invention 2), the thickness of the adhesive layer is preferably 1 μm or more and 1000 μm or less (invention 3).

In the above inventions (Inventions 2 and 3), the storage modulus of the adhesive layer at 23° C. is preferably 0.01 MPa or more and 50 MPa or less (Invention 4).

In the above inventions (Inventions 1 to 4), the thickness of the first film and the second film is preferably 45 μm or more (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that at least one of the first film and the second film is a release sheet whose surface facing the light diffusion control film is subjected to a release treatment (Invention 6).

In the above inventions (Inventions 1 to 6), the indentation modulus of the light diffusion control film at 23° C. is preferably 1 MPa or more and 5000 MPa or less (Invention 7).

In the above inventions (Inventions 1 to 7), the thickness of the light diffusion control film is preferably 20 μm or more and 700 μm or less (Invention 8).

According to the roll body of the laminated sheet according to the present invention, it is possible to provide a light diffusion control film in which the occurrence of dents is suppressed.

FIG. 1 is a cross-sectional view of a laminated sheet forming a roll body according to an embodiment of the present invention.

Embodiments of the present invention will be described below.
FIG. 1 shows a cross-sectional view of a laminated sheet constituting a roll body according to an embodiment of the present invention. The laminated sheet 1 shown in FIG. 1 includes a first film 11a, a light diffusion control film 12 laminated on one side of the first film 11a, and a side of the light diffusion control film 12 opposite to the first film 11a. and a second film 11b that is laminated on the side of the adhesive layer 13 opposite to the light diffusion control film 12. The roll body according to this embodiment is formed by winding up the laminated sheet 1 having such a layer structure. Note that in the roll body according to this embodiment, the above-described adhesive layer 13 is not essential and may be omitted.

1. Constituent members of roll body of laminated sheet (1) First film and second film In the laminated sheet 1 in this embodiment, the thickness of at least one of the first film 11a and the second film 11b is 45 μm or more. As a result, in the roll body according to the present embodiment, even if a foreign object is sandwiched, the influence of the foreign object on the light diffusion control film 12 can be suppressed by at least one of the first film 11a and the second film 11b. . As a result, the occurrence of dents on the light diffusion control film 12 is effectively suppressed. From this viewpoint, the thickness of at least one of the first film 11a and the second film 11b is preferably 60 μm or more, particularly preferably 70 μm or more. On the other hand, the upper limit of the thickness of at least one of the first film 11a and the second film 11b is not particularly limited, and may be, for example, 1000 μm or less, particularly 500 μm or less, and even 200 μm or less. It may be.

In addition, in the roll body according to this embodiment, even if only one of the first film 11a and the second film 11b has a thickness of 45 μm or more and the other has a thickness of less than 45 μm, the thickness of 45 μm or more The influence of foreign matter can be sufficiently suppressed by using a film having the following properties. On the other hand, when the first film 11a and the second film 11b both have a thickness of 45 μm or more, it becomes possible to suppress the influence of foreign matter by these two films, and further suppress the occurrence of dents. I can do it.

The structure and material of the first film 11a and the second film 11b are not particularly limited as long as they satisfy the above-mentioned thickness conditions for the first film 11a and the second film 11b. For example, these films may be any desired base material or may be a release sheet as described below. Further, these films may be composed of a resin-based sheet containing a resin-based material as a main component, or may be composed of a paper-based material. Note that the structures and materials of the first film 11a and the second film 11b may be the same or different.

The resin components in the resin sheet include polyolefins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, and norbornene resin, polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; Examples include resins such as polyvinyl chloride, vinyl chloride copolymer, polyimide, polyetherimide, polycarbonate, polyphenylene sulfide, and liquid crystal polymer. These resin sheets may be sheets consisting of a single layer, or may be sheets formed by laminating multiple layers of the same or different types. Among the above, polyethylene terephthalate film is preferred.

Specific examples of the first film 11a or the second film 11b being made of paper-based materials include paper base materials such as glassine paper, coated paper, and high-quality paper; Examples include laminated paper laminated with plastic resin.

At least one of the first film 11a and the second film 11b is made of a sheet made of the above-mentioned resin sheet or paper material, and one side (preferably the side on the light diffusion control film 12 side) is subjected to a release treatment. It may also be a release sheet. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

(2) Light Diffusion Control Film The light diffusion control film 12 in this embodiment has an internal structure in which a plurality of regions with a relatively high refractive index are included in a region with a relatively low refractive index. be. Furthermore, the light diffusion control film 12 according to the present embodiment has an internal structure in which a plurality of regions having a relatively high refractive index extend in the thickness direction within a region having a relatively low refractive index. It is preferable that it has a structure.

An example of the internal structure is a column structure in which a plurality of columnar objects having a relatively high refractive index are arranged in a series in the film thickness direction in a region having a relatively low refractive index. Another example is a louver structure in which a plurality of plate-like regions having different refractive indexes are arranged alternately in any direction along the film surface.

(2-1) Structure of Light Diffusion Control Film The specific structure and composition of the light diffusion control film 12 in this embodiment is not particularly limited, and conventionally known ones can be used. A preferable example of the light diffusion control film 12 includes a high refractive index component having one or two polymerizable functional groups, and a high refractive index component having a lower refractive index than the high refractive index component and one or two polymerizable functional groups. Examples include those obtained by curing a composition for a light diffusion control film containing a low refractive index component having a functional group. By using such a high refractive index component and a low refractive index component, the above-mentioned internal structure can be easily formed.

Preferred examples of the high refractive index component include (meth)acrylic esters containing an aromatic ring, particularly preferably (meth)acrylic esters containing a plurality of aromatic rings. Examples of (meth)acrylic esters containing multiple aromatic rings include biphenyl (meth)acrylate, naphthyl (meth)acrylate, anthracyl (meth)acrylate, benzylphenyl (meth)acrylate, and (meth)acrylate. Biphenyloxyalkyl acrylate, naphthyloxyalkyl (meth)acrylate, anthracyloxyalkyl (meth)acrylate, benzylphenyloxyalkyl (meth)acrylate, etc. Some of these are halogen, alkyl, alkoxy, and alkyl halide. Examples include those substituted by, etc. Among these, biphenyl (meth)acrylate is preferred from the viewpoint of easy formation of a good internal structure, and specifically, o-phenylphenoxyethyl acrylate, o-phenylphenoxyethoxyethyl acrylate, etc. are preferred. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The weight average molecular weight of the high refractive index component is preferably 2,500 or less, particularly preferably 1,500 or less, and even more preferably 1,000 or less. Further, the weight average molecular weight of the high refractive index component is preferably 150 or more, particularly preferably 200 or more, and even more preferably 250 or more. When the weight average molecule of the high refractive index component is within the above range, it becomes easier to form the light diffusion control film 12 having a desired internal structure. Note that the weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The refractive index of the high refractive index component is preferably 1.45 or more, more preferably 1.50 or more, particularly preferably 1.54 or more, and even more preferably 1.56 or more. is preferred. Further, the refractive index of the high refractive index component is preferably 1.70 or less, particularly preferably 1.65 or less, and even more preferably 1.59 or less. When the refractive index of the high refractive index component is within the above range, it becomes easier to form the light diffusion control film 12 having a desired internal structure. In addition, the refractive index in this specification means the refractive index of a predetermined component before curing the composition for a light diffusion control film, and the refractive index is measured according to JIS K0062:1992. It is.

The content of the high refractive index component in the composition for a light diffusion control film is preferably 25 parts by mass or more, particularly preferably 40 parts by mass or more, based on 100 parts by mass of the low refractive index component. Furthermore, it is preferably 50 parts by mass or more. Further, the content of the high refractive index component in the composition for a light diffusion control film is preferably 400 parts by mass or less, particularly 300 parts by mass or less, based on 100 parts by mass of the low refractive index component. The amount is preferably 200 parts by mass or less. By having the content of the high refractive index component within these ranges, in the internal structure of the formed light diffusion control film, the area derived from the high refractive index component and the area derived from the low refractive index component can be in the desired ratio. As a result, the light diffusion control film can easily achieve the desired light diffusion property.

Preferred examples of the low refractive index component include urethane (meth)acrylate, (meth)acrylic polymers having (meth)acryloyl groups in side chains, silicone resins containing (meth)acryloyl groups, and unsaturated polyester resins. However, it is particularly preferable to use urethane (meth)acrylate.

The urethane (meth)acrylate is preferably formed from (a) a compound containing at least two isocyanate groups, (b) polyalkylene glycol, and (c) hydroxyalkyl (meth)acrylate.

Preferred examples of the above-mentioned (a) compound containing at least two isocyanate groups include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1, Aromatic polyisocyanates such as 4-xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, and their biuret forms, isocyanurate forms, and adduct forms (e.g., xylylene diisocyanate), which are reactants with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. trifunctional adducts) and the like. Among these, cycloaliphatic polyisocyanates are preferred, and cycloaliphatic diisocyanates containing only two isocyanate groups are particularly preferred.

Preferred examples of the above-mentioned polyalkylene glycol (b) include polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexylene glycol, etc. Among them, polypropylene glycol is preferred.

The weight average molecular weight of the polyalkylene glycol (b) is preferably 2,300 or more, particularly preferably 4,300 or more, and even more preferably 6,300 or more. The weight average molecular weight of the polyalkylene glycol (b) is preferably 19,500 or less, particularly preferably 14,300 or less, and even more preferably 12,300 or less.

Preferred examples of the above-mentioned (c) hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. ) acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Among these, it is preferable to use 2-hydroxyethyl methacrylate from the viewpoint of reducing the polymerization rate of the resulting urethane (meth)acrylate and forming a predetermined internal structure more efficiently.

Synthesis of urethane (meth)acrylate using the above-mentioned components (a) to (c) can be carried out according to a conventional method. At this time, from the viewpoint of efficiently synthesizing urethane (meth)acrylate, the blending ratio of components (a) to (c) is determined in terms of molar ratio: (a) component: (b) component: (c) component = The ratio is preferably 1 to 5:1:1 to 5, particularly preferably 1 to 3:1:1 to 3, and even more preferably 2:1:2.

The weight average molecular weight of the low refractive index component is preferably 3,000 or more, particularly preferably 5,000 or more, and even more preferably 7,000 or more. Further, the weight average molecular weight of the low refractive index component is preferably 20,000 or less, particularly preferably 15,000 or less, and even more preferably 13,000 or less. By having the weight average molecular weight of the low refractive index component within the above range, it becomes easy to form the light diffusion control film 12 having desired performance.

The refractive index of the low refractive index component is preferably 1.59 or less, more preferably 1.50 or less, particularly preferably 1.49 or less, and even more preferably 1.48 or less. is preferred. Further, the refractive index of the low refractive index component is preferably 1.30 or more, particularly preferably 1.40 or more, and even more preferably 1.46 or more. When the refractive index of the low refractive index component is within the above range, it becomes easy to form a desired light diffusion control film.

The composition for a light diffusion control film described above may contain other additives in addition to the high refractive index component and the low refractive index component. Other additives include, for example, polyfunctional monomers (compounds having three or more polymerizable functional groups), photopolymerization initiators, antioxidants, ultraviolet absorbers, antistatic agents, polymerization accelerators, and polymerization inhibitors. , infrared absorbers, plasticizers, diluting solvents, and leveling agents.

Among the additives mentioned above, it is preferable that the composition for a light diffusion control film contains a polyfunctional monomer. As a result, the obtained light diffusion control film 12 has relatively high elasticity, which prevents the occurrence of dents when manufacturing the light diffusion control film 12 and when laminating the light diffusion control film on other members. This makes it easier to more effectively suppress the occurrence of collapse.

Moreover, it is also preferable that the composition for a light diffusion control film contains a photopolymerization initiator. When the composition for a light diffusion control film contains a photopolymerization initiator, it becomes easy to efficiently form a light diffusion control film having a desired internal structure.

Examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 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-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl Examples include dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoate, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane], and the like. These may be used alone or in combination of two or more.

When using a photopolymerization initiator, the content of the photopolymerization initiator in the composition for a light diffusion control film is 0.2 parts by mass based on 100 parts by mass of the total amount of the high refractive index component and the low refractive index component. It is preferably at least 0.5 parts by mass, particularly preferably at least 0.5 parts by mass, and even more preferably at least 1 part by mass. Further, the content of the photopolymerization initiator is preferably 20 parts by mass or less, particularly preferably 15 parts by mass or less, based on 100 parts by mass of the total amount of the high refractive index component and the low refractive index component. The amount is preferably 10 parts by mass or less. By setting the content of the photopolymerization initiator in the composition for a light diffusion control film within the above range, the light diffusion control film 12 can be easily formed efficiently.

The composition for a light diffusion control film can be prepared by uniformly mixing the above-described high refractive index component and low refractive index component, and other additives if desired. During mixing, the mixture may be stirred while being heated to a temperature of 40 to 80° C. to obtain a uniform composition for a light diffusion control film. Further, a diluting solvent may be added and mixed so that the resulting composition for a light diffusion control film has a desired viscosity.

(2-2) Indentation modulus of light diffusion control film The lower limit of the indentation modulus of elasticity at 23° C. of the light diffusion control film 12 in this embodiment is preferably 1 MPa or more, particularly 10 MPa or more. It is preferable, and more preferably 20 MPa or more. When the lower limit of the indentation modulus is within the above range, it becomes possible to more effectively suppress the occurrence of dents in the light diffusion control film 12. The upper limit of the indentation modulus is preferably 5000 MPa or less, more preferably 1000 MPa or less, particularly preferably 300 MPa or less, and even more preferably 40 MPa or less. When the upper limit of the indentation modulus is within the above range, the light diffusion control film 12 has appropriate flexibility, and the light diffusion control film 12 can easily have desired handling properties. Note that the details of the method for measuring the indentation modulus are as described in Examples described later.

(2-3) Thickness of light diffusion control film The lower limit of the thickness of the light diffusion control film 12 in this embodiment is preferably 20 μm or more, particularly preferably 40 μm or more, and more preferably 60 μm. It is preferable that it is above. When the lower limit of the thickness of the light diffusion control film 12 is within the above range, desired light diffusion properties can be easily exhibited. The upper limit of the thickness of the light diffusion control film 12 is preferably 700 μm or less, particularly preferably 400 μm or less, and even more preferably 200 μm or less. When the upper limit of the thickness of the light diffusion control film 12 is within the above range, it becomes easier to more effectively suppress the occurrence of dents.

(2-4) Ratio of internal structure in the thickness direction of the light diffusion control film As described above, the light diffusion control film 12 in this embodiment has a relatively low refractive index in a region within the film that has a relatively low refractive index. It is preferable that the internal structure has a plurality of regions extending in the thickness direction. Here, the proportion of the internal structure extending in the thickness direction is preferably 10% or more of the thickness of the light diffusion control film 12, and 30% or more of the thickness of the light diffusion control film 12, from the viewpoint of making light diffusion more efficient. % or more, and particularly preferably 50% or more. Note that the upper limit value is not limited and may be 100%, that is, the internal structure may be formed in the entire thickness direction.

(3) Adhesive layer The laminated sheet in this embodiment may include an adhesive layer 13. By providing the adhesive layer 13, it becomes easy to fix the light diffusion control film 12 supplied from the roll body according to this embodiment to a desired member via the adhesive layer 13. In addition, in the roll body according to this embodiment, as described above, the occurrence of dents is suppressed by the first film 11a and the second film 11b satisfying the above-described thickness conditions. Therefore, from the viewpoint of suppressing the occurrence of dents, it is not necessary to intentionally provide the adhesive layer 13.

The adhesive constituting the adhesive layer 13 is not particularly limited as long as it has the desired adhesiveness and does not impair the effect of suppressing the occurrence of dents as described above, and conventionally known adhesives can be used. can. For example, acrylic adhesives, silicone adhesives, urethane adhesives, rubber adhesives, etc. can be used as the adhesive, among which acrylic adhesives can easily achieve good adhesiveness and transparency. Adhesives are preferred.

Examples of the above-mentioned acrylic pressure-sensitive adhesives include pressure-sensitive adhesives obtained by crosslinking a pressure-sensitive adhesive composition containing a (meth)acrylic acid ester polymer and a crosslinking agent. In addition, in this specification, the concept of "copolymer" is also included in "polymer".

The (meth)acrylic acid ester polymer preferably contains a reactive group-containing monomer having a reactive group that reacts with a crosslinking agent in the molecule as a monomer unit constituting the polymer. When the reactive group reacts with the crosslinking agent described below, the cohesive force of the resulting pressure-sensitive adhesive can be controlled, and the storage modulus can be easily adjusted to a suitable range. The functional group-containing monomer is preferably a monomer that has a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, or an amino group in the molecule, and among these monomers that contain a carboxy group as a functional group. It is preferable to use at least one of a monomer (carboxy group-containing monomer) and a hydroxy group-containing monomer (hydroxy group-containing monomer).

Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and among these, acrylic acid is preferred. Preferred examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. These may be used alone or in combination of two or more.

The (meth)acrylic acid ester polymer preferably contains 1% by mass or more, particularly preferably 5% by mass or more, of structural units derived from the above-mentioned functional group-containing monomer. Moreover, it is preferable that the said polymer contains the said structural unit in 40 mass % or less, and it is especially preferable to contain it in 20 mass % or less.

From the viewpoint of developing adhesive strength, the (meth)acrylic acid ester polymer preferably contains (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer, and in particular, the number of carbon atoms in the alkyl group is 1. Preference is given to using acrylic acid alkyl esters having a molecular weight of ˜18. Specific examples thereof include methyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. These may be used alone or in combination of two or more.

From the viewpoint of achieving both adhesive strength and storage modulus, the (meth)acrylic acid ester polymer preferably contains 50% by mass or more of structural units derived from the above-mentioned (meth)acrylic acid alkyl ester, particularly 80% by mass or more. It is preferable that the content is at least % by mass. Moreover, it is preferable that the said polymer contains the said structural unit in 99 mass % or less, and it is especially preferable to contain it in 95 mass % or less.

The (meth)acrylic acid ester polymer may be one obtained by copolymerizing other monomers together with the above-mentioned functional group-containing monomer and (meth)acrylic acid alkyl ester. Moreover, regarding the polymerization mode of the polymer, it may be a random copolymer or a block copolymer. Moreover, the said polymer may be used individually by 1 type, and may be used in combination of 2 or more types.

The weight average molecular weight of the (meth)acrylic acid ester polymer is preferably 300,000 or more, particularly preferably 1,000,000 or more, from the viewpoint of obtaining a suitable storage modulus. Further, the weight average molecular weight is preferably 2.5 million or less, particularly preferably 2 million or less.

The crosslinking agent may be any one as long as it reacts with the reactive functional group of the (meth)acrylic acid ester polymer, and it is preferable to use, for example, an epoxy crosslinking agent, an isocyanate crosslinking agent, and the like. In addition, a crosslinking agent can be used individually or in combination of two or more types.

The content of the crosslinking agent in the adhesive composition is preferably 0.01 parts by mass or more, particularly 0.1 parts by mass or more, based on 100 parts by mass of the (meth)acrylic acid ester polymer. is preferred. Further, the content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less.

The adhesive composition may optionally contain various additives commonly used in acrylic adhesives, such as active energy ray-curable components, photopolymerization initiators, silane coupling agents, antistatic agents, and tackifiers. , antioxidants, light stabilizers, softeners, fillers, refractive index modifiers, etc. can be added.

When the adhesive composition contains an active energy ray-curable component, the adhesive layer 13 made of an active energy ray-curable adhesive can be formed. The active energy ray-curable component is not particularly limited as long as it is a component that can cure the adhesive layer 13 by irradiation with active energy rays, and may be a monomer, oligomer, or polymer, or a mixture thereof. It may be. Among these, polyfunctional acrylate monomers having excellent compatibility with (meth)acrylic acid ester copolymers and the like can be preferably mentioned. Note that by using an active energy ray-curable component, the storage modulus of the resulting adhesive can be increased.

The adhesive composition can be manufactured by manufacturing a (meth)acrylic ester polymer and mixing the obtained (meth)acrylic ester polymer, a crosslinking agent, and optionally an additive. . The (meth)acrylic acid ester polymer can be produced by polymerizing a mixture of monomers constituting the polymer using a conventional radical polymerization method. The (meth)acrylic acid ester polymer is preferably polymerized by a solution polymerization method using a polymerization initiator if desired. The adhesive composition may be used as a coating solution of the adhesive composition by adding a diluting solvent and thoroughly mixing the mixture.

The storage modulus at 23° C. of the adhesive layer 13 in this embodiment is preferably 0.01 MPa or more, more preferably 0.11 MPa or more, particularly preferably 0.20 MPa or more, and is preferably 0.40 MPa or more. Moreover, the storage elastic modulus of the adhesive layer 13 at 23° C. is preferably 50 MPa or less, particularly preferably 10 MPa or less, and even more preferably 1 MPa or less. When the storage elastic modulus of the adhesive layer 13 at 23° C. is within the above range, the adhesive layer 13 can easily reduce the influence of foreign matter caught between the roll bodies while ensuring adhesive strength. In particular, since the storage modulus is 0.01 MPa or more, it is likely to be effective in eliminating dents from the first film side (the film laminated on the side of the light diffusion control film that is not in contact with the adhesive layer). Become something. Thereby, the occurrence of dents on the light diffusion control film 12 can be more effectively suppressed. Note that the storage elastic modulus at 23° C. of the adhesive layer 13 means, when the adhesive layer 13 is made of the above-mentioned active energy ray-curable adhesive, the adhesive after being cured by irradiation with active energy rays. It refers to the storage elastic modulus of the agent layer 13. Further, the details of the method for measuring the storage modulus are as described in the test examples described below.

The thickness of the adhesive layer 13 is preferably 1000 μm or less, more preferably 100 μm or less, particularly preferably 50 μm or less, and even more preferably 20 μm or less. When the thickness of the adhesive layer 13 is 1000 μm or less, it becomes easy to suppress the occurrence of dents in the adhesive layer 13. Further, the thickness of the adhesive layer 13 is preferably 1 μm or more, particularly preferably 5 μm or more, and even more preferably 10 μm or more. When the thickness of the adhesive layer 13 is 1 μm or more, desired adhesiveness can be easily exhibited.

(4) Others The laminated sheet 1 in this embodiment may include layers other than the layers described above, as long as the effect of suppressing dents is not impaired. Moreover, the roll body according to this embodiment may be formed by winding the laminated sheet 1 around a core material.

The winding core is not particularly limited as long as it is possible to wind up the laminated sheet 1 in this embodiment, and any known core can be used. The material constituting the core material preferably has sufficient strength for winding the laminated sheet 1, and examples thereof include resin, metal, wood, and the like.

2. Method for manufacturing a roll body of a laminated sheet The method for manufacturing a roll body of a laminated sheet according to this embodiment is not particularly limited, and a conventionally known method can be adopted.

As an example, after obtaining a laminate (first laminate) formed by laminating the first film 11a and the light diffusion control film 12, a surface of the first laminate on the light diffusion control film 12 side may be On the other hand, the second film 11b is laminated. By winding up the thus obtained laminated sheet 1 in which the first film 11a, the light diffusion control film 12, and the second film 11b are laminated in this order, a roll body of the laminated sheet according to the present embodiment is obtained. be able to.

Further, together with a laminate (first laminate) formed by laminating the first film 11a and the light diffusion control film 12, a laminate (second laminate) formed by laminating the second film 11b and the adhesive layer 13, Prepare a laminate). Then, the surface of the first laminate on the light diffusion control film 12 side and the surface of the second laminate on the adhesive layer 13 side are bonded together. By winding up the laminated sheet 1 obtained by this, in which the first film 11a, the light diffusion control film 12, the adhesive layer 13, and the second film 11b are laminated in this order, the laminated sheet according to the present embodiment can be A roll of sheet can be obtained.

The method for manufacturing the above-described laminate (first laminate) formed by laminating the first film 11a and the light diffusion control film 12 is not particularly limited, and can be manufactured by a conventionally known method. For example, after applying the above-described composition for a light diffusion control film to one side of a process sheet to form a coating film, one side of the first film 11a is applied to the opposite side of the coating film from the process sheet. match. Subsequently, the coating film is irradiated with active energy rays through the first film 11a and cured, thereby forming the light diffusion control film 12. In this way, by laminating the first film 11a on the coating film, the gap between the first film 11a and the process sheet is maintained, the coating film is suppressed from being crushed, and light diffusion with a uniform thickness is achieved. This makes it easier to form the control film 12. By forming the light diffusion control film 12 in the above manner, the first laminate consisting of the first film 11a and the light diffusion control film 12 is brought into a state in which the process film is attached to the surface of the light diffusion control film 12. You can get it at

Examples of the above-mentioned coating methods include knife coating, roll coating, bar coating, blade coating, die coating, and gravure coating. Further, the composition for a light diffusion control film may be diluted with a solvent if necessary.

The coating film is irradiated with active energy rays in different ways depending on the internal structure to be formed. Such irradiation can be performed by a conventionally known method. For example, when forming the above-described column structure, the coating film is irradiated with parallel light having a high degree of parallelism. On the other hand, when forming the above-mentioned louver structure, a linear light source is used as a light source of active energy rays. Emits parallel band-shaped (almost linear) light.

Note that the active energy rays refer to electromagnetic waves or charged particle beams that have energy quantum, and specifically include ultraviolet rays and electron beams. Among active energy rays, ultraviolet rays are particularly preferred because they are easy to handle.

When forming a column structure using ultraviolet rays as active energy rays, the irradiation conditions are preferably such that the peak illuminance at the coating surface is 0.1 to 10 mW/cm ² . In addition, the peak illumination intensity here means the measured value at the part where the active energy ray irradiated to the coating film surface shows the maximum value. Further, it is preferable that the cumulative amount of light on the surface of the coating film is 5 to 200 mJ/cm ² .

When forming a louver structure using ultraviolet rays as active energy rays, the irradiation conditions are preferably such that the peak illuminance on the coating surface is 0.1 to 50 mW/cm ² or less. Furthermore, it is preferable that the cumulative amount of light on the surface of the coating film be 5 to 300 mJ/cm ² or less.

In addition, in order to complete curing more reliably, after curing using parallel light or band-shaped light as described above, normal active energy rays (processing to convert them into parallel light or band-shaped light are performed). It is also preferable to irradiate with active energy rays or scattered light.

The method for producing the above-mentioned laminate (second laminate) formed by laminating the second film 11b and the adhesive layer 13 is not particularly limited, and can be performed by a conventionally known method. For example, an adhesive material constituting the adhesive layer 13 is applied to one side of the second film 11b. The adhesive layer 13 can be formed by drying the coating film thus obtained.

By winding the laminated sheet 1 manufactured as described above, a roll body of the laminated sheet is obtained. At this time, the laminated sheet 1 may be wound around the core material described above. Further, the above-described production of the first laminate (and second laminate), formation of the laminate sheet 1, and winding of the formed laminate sheet 1 may be performed continuously. For example, a first laminate and a second laminate are manufactured upstream in the flow direction, and the obtained first laminate and second laminate are laminated downstream in the flow direction, thereby A roll body may be obtained by further winding the obtained laminated sheet 1.

3. Use of roll body of laminated sheet The roll body of laminated sheet according to this embodiment can be used for providing the light diffusion control film 12. For example, the laminate sheet 1 is unrolled from a roll, cut into a desired shape, the first film 11a and the second film 11b are peeled off at a desired timing, and the light diffusion control film 12 ( When the laminate sheet 1 includes the adhesive layer 13, a laminate of the light diffusion control film 12 and the adhesive layer 13 can be provided. Such a light diffusion control film 12 can be successfully used for manufacturing liquid crystal displays, organic light emitting devices, electronic paper, etc.

In particular, according to the roll body of the laminated sheet according to this embodiment, the occurrence of dents on the light diffusion control film 12 can be suppressed favorably. Therefore, in the light diffusion control film 12 provided from the roll body according to this embodiment, performance such as light diffusivity is not impaired. By using such a light diffusion control film, it becomes possible to manufacture a device having desired performance.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

Hereinafter, the present invention will be explained in more detail with reference to examples, but the scope of the present invention is not limited to these examples.

[Example 1]
(1) Formation of light diffusion control film 40 mass of polyether urethane methacrylate with a weight average molecular weight of 9,900 obtained by reacting polypropylene glycol, isophorone diisocyanate, and 2-hydroxyethyl methacrylate as a low refractive index component (solid content equivalent; the same applies hereinafter), 60 parts by mass of o-phenylphenoxyethoxyethyl acrylate with a molecular weight of 268 as a high refractive index component and 2-hydroxy-2-methyl-1 as a photopolymerization initiator. After adding 8 parts by mass of -phenylpropan-1-one, heating and mixing was performed at 80° C. to obtain a composition for a light diffusion control film.

The obtained composition for a light diffusion control film was applied to one side of a long polyethylene terephthalate sheet as a process sheet to form a coating film. Subsequently, a release sheet (manufactured by Lintec, product name: "SP-PET381130" made by Lintec Corporation, product name: '', thickness: 38 μm) was laminated on the peeled surface.

The resulting laminate consisting of the first film, the coating film, and the process sheet was placed on a conveyor. At this time, the surface of the laminate facing the first film was the upper side, and the longitudinal direction of the laminate was parallel to the flow direction of the conveyor. Then, an ultraviolet spot parallel light source (manufactured by JATEC Corporation) whose center beam parallelism was controlled within ±3° was installed on the conveyor on which the laminate was placed. At this time, the light source was installed so that it could irradiate parallel light in a direction inclined by 15 degrees to the opposite side to the flow direction of the conveyor with respect to the normal direction of the surface of the laminate on the first film side. Moreover, the distance between the surface of the first film and the light source was 240 mm.

After that, while operating ^the conveyor and moving the laminate at a speed of 0.2 m/ ^min , the parallelism was The coating film in the laminate was cured by irradiating it with parallel light (ultraviolet rays from a high-pressure mercury lamp having a main peak wavelength of 365 nm and other peaks at 254 nm, 303 nm, and 313 nm) having an angle of 2° or less. As a result, a light diffusion control film having a thickness of 60 μm was formed by curing the above-described coating film. Furthermore, by peeling the process sheet from the laminate, a first laminate in which the first film and the light diffusion control film were laminated in this order was obtained.

The indentation modulus of the obtained light diffusion control film at 23°C was measured using an ultra-micro hardness meter (Shimadzu Dynamic Ultra-micro Hardness Meter DUH-W201S, manufactured by Shimadzu Corporation). It was 27 MPa. In addition, microscopic observation of the cross section of the formed light diffusion control film revealed that a column structure consisting of a plurality of columnar objects standing in the entire thickness direction was formed inside the light diffusion control film. was confirmed. That is, the ratio of column structure regions extending in the thickness direction inside the obtained light diffusion control film was 100%. Furthermore, it was confirmed that the above-mentioned columnar objects were inclined at 20° (inclination angle -20°) in the direction of the thickness of the light diffusion control film on the opposite side to the traveling direction of the conveyor. Note that the inclination angle is expressed as 0° in the direction normal to the film surface, plus in the conveyor traveling direction, and minus in the opposite direction.

In addition, the peak illuminance and cumulative light intensity described above were measured by installing a UV METER (manufactured by Eye Graphics, product name: "Eye Ultraviolet Integrated Illuminance Meter UVPF-A1") equipped with a light receiver at the position of the above coating film. It is something. The thickness of the light diffusion control film was measured using a constant pressure thickness measuring device (manufactured by Takara Seisakusho Co., Ltd., product name: "Techlock PG-02J").

(2) Formation of adhesive layer 90 parts by mass of n-butyl acrylate and 10 parts by mass of acrylic acid were polymerized by a solution polymerization method to obtain a (meth)acrylic acid ester polymer. The weight average molecular weight (Mw) of this (meth)acrylic acid ester polymer was measured by the method described below and was found to be 400,000.

100 parts by mass of the (meth)acrylic acid ester polymer obtained above and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name "TETRAD") as a crosslinking agent. -C'') and 0.05 parts by mass were mixed in a solvent to obtain a coating liquid of an adhesive composition.

Subsequently, the coating solution of the obtained adhesive composition was applied to a release sheet (manufactured by Lintec, product name: "SP-PET752150", manufactured by Lintec Corporation, product name: A pressure-sensitive adhesive layer with a thickness of 25 μm was formed on the second film by coating the adhesive layer on the release surface (thickness: 75 μm) and heating at 90° C. for 1 minute. Thereby, a second laminate in which the second film and the adhesive layer were laminated was obtained.

Note that the storage modulus of the formed adhesive layer at 23° C. was measured in Test Example 1 described later, and was found to be 0.16 MPa. Further, the above-mentioned thickness of the adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by Techlock Co., Ltd., product name "PG-02") in accordance with JIS K7130.

(3) Formation of a laminate sheet The surface on the light diffusion control film side of the first laminate obtained in the above step (1) and the adhesive layer side of the second laminate obtained in the above step (2) The first film, the light diffusion control film, the adhesive layer, and the second film are bonded to each other by seasoning for 168 hours at a temperature of 23°C and a relative humidity of 50%. A laminated sheet was obtained by laminating the layers in this order.

Here, the weight average molecular weight (Mw) mentioned above is the weight average molecular weight in terms of standard polystyrene measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement).
<Measurement conditions>
・Measuring device: Tosoh Corporation, HLC-8320
・GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel superHM-H
TSK gel superH2000
・Measurement solvent: Tetrahydrofuran ・Measurement temperature: 40℃

[Examples 2 to 4, Comparative Example 1]
A laminated sheet was produced in the same manner as in Example 1, except that the thicknesses of the first film and the second film were changed as shown in Table 1.

[Example 5]
98.5 parts by mass of n-butyl acrylate and 1.5 parts by mass of 2-hydroxyethyl acrylate were polymerized by a solution polymerization method to obtain a (meth)acrylic ester polymer having a weight average molecular weight (Mw) of 2 million. Combined A was obtained.

Further, 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid were polymerized by a solution polymerization method to obtain a (meth)acrylic acid ester polymer B having a weight average molecular weight (Mw) of 2 million.

The weight average molecular weight (Mw) of these (meth)acrylic acid ester polymers was measured under the same conditions as in Example 1.

Subsequently, 100 parts by mass of the (meth)acrylic ester polymer A, 10 parts by mass of the (meth)acrylic ester polymer B, and tris(acryloxyethyl)isocyanurate (Toagosei Co., Ltd.) as an active energy ray-curable component. 15 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent were mixed in a solvent. , a coating solution of an adhesive composition was obtained.

A release sheet (manufactured by Lintec, product name: "SP-PET752150", thickness: 75 μm), in which one side of a polyethylene terephthalate film was treated with a silicone release agent as a second film, was coated with the coating solution of the above-mentioned adhesive composition. ) was applied using a knife-type coating machine, and then dried at 90° C. for 1 minute to form a coating film.

Next, a release sheet (manufactured by Lintec, product name "SP-PET382120", thickness A peeled surface of 38 μm) was bonded. Thirty minutes after lamination, ultraviolet rays (UV) were irradiated through the second film under the following conditions, and the coating film was cured to form an adhesive layer with a thickness of 15 μm. Then, by peeling off the release sheet (having a thickness of 38 μm) from the adhesive layer, a second laminate in which the second film and the adhesive layer were laminated was obtained.
<UV irradiation conditions>
・Electrodeless lamp manufactured by Fusion, H bulb used ・Illuminance: 600mW/cm ² , Light intensity: 150mJ/cm ²
・The UV illuminance/light meter uses “UVPF-36” manufactured by Eye Graphics.

A laminate sheet was produced in the same manner as in Example 1, except that the second laminate obtained as described above was used.

In addition, when the storage elastic modulus of the formed adhesive layer at 23° C. was measured in Test Example 1 described later, it was 0.59 MPa.

[Example 6, Comparative Example 2]
A laminated sheet was produced in the same manner as in Example 5, except that the thicknesses of the first film and the second film were changed as shown in Table 2.

[Test Example 1] (Measurement of storage modulus of adhesive layer)
A plurality of seasoned adhesive layers obtained in Examples and Comparative Examples were laminated to form a laminate with a thickness of 3 mm. A cylindrical body with a diameter of 8 mm (height: 3 mm) was punched out from the obtained adhesive layer laminate and used as a sample.

The storage modulus (G') (MPa) of the above sample was measured under the following conditions using a viscoelasticity measuring instrument (manufactured by REOMETRIC, product name "DYNAMIC ANALAYZER") by the torsional shear method in accordance with JIS K7244-6. was measured.
Measurement frequency: 1Hz
Measurement temperature: 23℃

[Test Example 2] (Measurement of dents)
(1) Regarding Example 1, Example 2, and Comparative Example 1 The laminated sheets of Example 1, Example 2, and Comparative Example 1 were placed horizontally on a glass with the second film side facing up. fixed on the board. Then, a hardness tester (manufactured by Kobunshi Keiki Co., Ltd., product name "Asker Hardness Tester C2") with a hemisphere tip with a diameter of 2.54 mm was used to measure the surface of the laminated sheet on the second film side. A point load was applied for 10 seconds at a load of 225 g.

After 5 minutes had passed from the application of the point load, the second film was peeled off from the laminated sheet, and the depth (μm) of the dents remaining on the exposed surface of the adhesive layer was measured using an optical interference microscope (Veeco Co., Ltd.). The measurement was carried out using a surface profile measuring device (WYKO NT110, manufactured by Manufacturer, Inc.). The results are shown in Table 1. Further, the ratio (%) based on the depth measured in Comparative Example 1 was calculated, and the results are also shown in Table 1.

In addition, the same measurements as above were carried out by changing the load to 443 g. Table 1 also shows the depth (μm) of the resulting dents and the percentage (%) based on the depth measured in Comparative Example 1.

(2) Regarding Example 3, Example 4, and Comparative Example 1 The laminated sheets of Example 3, Example 4, and Comparative Example 1 were placed horizontally on a glass with the first film side facing up. fixed on the board. Then, a point load of 225 g or 443 g was applied to the first film side surface of the laminated sheet in the same manner as in (1) above.

After 5 minutes have passed from the application of the point load, the first film is peeled off from the laminated sheet, and the depth (μm) of the dents remaining on the exposed surface of the light diffusion control film is measured using an optical interference microscope (Veeco). The measurement was carried out using a surface profile measuring device (WYKO NT110, manufactured by Co., Ltd., product name: "Surface shape measuring device WYKO NT110"). The results are shown in Table 1. Further, the ratio (%) based on the depth measured in Comparative Example 1 was calculated, and the results are also shown in Table 1.

(3) Regarding Example 5 and Comparative Example 2 Regarding the laminated sheets of Example 5 and Comparative Example 2, the depth of dents (μm ) was measured. Furthermore, the ratio (%) based on the depth measured in Comparative Example 2 was also calculated. These results are shown in Table 2.

(4) Regarding Example 6 and Comparative Example 2 Regarding the laminated sheets of Example 6 and Comparative Example 2, the depth of dents (μm ) was measured. Furthermore, the ratio (%) based on the depth measured in Comparative Example 2 was also calculated. These results are shown in Table 2.

As is clear from Tables 1 and 2, in the laminated sheet according to the example, even when a point load was applied, the depth of the resulting dents could be reduced favorably. From this result, it is presumed that in the roll body of the laminated sheet according to the example, even if foreign matter is caught, the occurrence of dents can be suppressed well.

The roll body of the laminated sheet of the present invention is suitably used for manufacturing devices and the like equipped with a light diffusion control film.

1... Laminated sheet 11a... First film 11b... Second film 12... Light diffusion control film 13... Adhesive layer

Claims (8)

First film and
an internal structure laminated on one side of the first film, the film having a plurality of regions having a relatively high refractive index extending in the thickness direction within a region having a relatively low refractive index; a light diffusion control film having;
A roll body formed by winding up a laminated sheet comprising a second film laminated on the side opposite to the first film in the light diffusion control film,
The internal structure is a column structure in which a plurality of columnar objects with a relatively high refractive index are arranged in the film thickness direction in a region with a relatively low refractive index, or a plurality of columnar objects with different refractive indexes are formed. It has a louver structure in which plate-like areas are arranged alternately in any direction along the film surface,
A roll body of a laminated sheet, wherein the thickness of at least one of the first film and the second film is 45 μm or more. The roll body of a laminated sheet according to claim 1, further comprising an adhesive layer provided between the light diffusion control film and the second film. The roll body of a laminated sheet according to claim 2, wherein the thickness of the adhesive layer is 1 μm or more and 1000 μm or less. The roll body of a laminated sheet according to claim 2 or 3, wherein the adhesive layer has a storage modulus at 23° C. of 0.01 MPa or more and 50 MPa or less. The roll body of a laminated sheet according to any one of claims 1 to 4, wherein the first film and the second film have a thickness of 45 μm or more. The laminate according to any one of claims 1 to 5, wherein at least one of the first film and the second film is a release sheet whose surface facing the light diffusion control film is subjected to a release treatment. Sheet roll. The roll body of a laminated sheet according to any one of claims 1 to 6, wherein the light diffusion control film has an indentation modulus of elasticity at 23° C. of 1 MPa or more and 5000 MPa or less. The roll body of a laminated sheet according to claim 1, wherein the thickness of the light diffusion control film is 20 μm or more and 700 μm or less.

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