JPH11271503A - Film for lens sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for a lens sheet which improves the adhesiveness to a lens layer consisting of many lens units disposed on a thermoplastic resin film, improves the adhesiveness under a variety of environments and more particularly at and under a high temp. and high humidity and has excellent durability. SOLUTION: This film is constituted by composing the lens sheet disposed adjacently to one side of the lens layer, consisting this lens sheet of the thermoplastic resin film and providing at least one side on the lens layer side of the film with laminated films contg. at least one among an amide ester bond, urethane bond, amide bond and urea bond.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens sheet film which is used as a base film when forming a lens sheet used for a liquid crystal display or the like.

More specifically, the present invention relates to a film for a lens sheet using a thermoplastic resin film provided with a laminated film, and more particularly to a film for a lens sheet having excellent durability even under various environments. is there. In the present invention, a lens sheet refers to a sheet having a sheet-like basic structure in which a large number of lens units have a lens surface in parallel on one surface, and described in, for example, JP-A-8-286005. It means something like

[0003]

2. Description of the Related Art In recent years, there has been a remarkable spread in portable electronic devices of small size, light weight, and color, as represented by colorization and size reduction of notebook type personal computers in recent years. In particular, products that use color LCDs are not limited to color notebook computers, but a wide variety of products such as portable color LCD TVs, video-integrated color LCD TVs, handy label printers, and portable communication devices (mobile gear, etc.). There is something.

[0004] In such devices, a battery is used to make the device portable, and its operation time is limited. In particular, the power consumption of a liquid crystal display, especially a color liquid crystal display, greatly affects the operation time of a battery. By reducing this power consumption, the practical commercial value of the portable electric device described above is increased. be able to. At the same time, achieving energy savings is significant from a global environmental perspective.

The simplest method of reducing power consumption is to reduce the power consumption of a backlight used in a liquid crystal display. But in this case,
Since the brightness of the backlight is reduced, the brightness of the liquid crystal display is also reduced, and the display function is significantly reduced.

[0006] In order to solve this problem, methods for improving the optical efficiency of the backlight have been proposed. For example,
A backlight provided with a lens sheet such as a lens sheet formed with a large number of lens units in a prism array or a sheet formed with a large number of lens units in a lenticular array on one side on the emission light side of a light guide of the backlight. Proposed.

[0007] Such a lens sheet improves the front luminance by directing the light emitted from the backlight toward the front of the display by refraction. Usually, a lens sheet has a configuration in which a plastic resin having excellent transparency such as a polycarbonate resin, an acrylic resin, and a polyester resin is used as a base material because of its good moldability, and a large number of lens units are formed on at least one surface. Have been.

[0008] On the other hand, while recent electric equipment has become highly functional, the burden on the equipment main body has become extremely large. In particular, the thermal burden is beyond imagination, and the liquid crystal display described above is no exception, and the heat generated by the light source of the backlight is greatly affected. For example, as the influence, a problem such as peeling of a lens portion of a lens sheet provided for improving the brightness may occur, and the product value may be lost.

Furthermore, in recent years, the above-mentioned electric equipment has been developed in a wide range of applications, and thus, in various environments, for example,
Since it is used under a low temperature, a high temperature, a low humidity, a high humidity, or an environment in which these are combined, the above-described phenomenon can be sufficiently accelerated.

As a method for the above-mentioned phenomenon, use of a transparent resin film serving as a base material, which has been subjected to various kinds of easy-adhesion treatments, has been studied. For example, a surface activation method of performing corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, or the like on the surface, a surface etching method using a chemical such as an acid, an alkali, or an amine aqueous solution, or an acrylic resin or polyester resin having adhesiveness to the film surface And a method in which various resins such as urethane resin and polyolefin resin are provided as a primer layer.

[0011] In particular, the method of providing a primer layer can select and coat an adhesive substance that can cope with various coating materials. Therefore, a water-soluble or water-dispersible polyester resin, acrylic resin, urethane or the like can be used. A resin or the like laminated on a polyester film as an adhesive substance (JP-A-55-15825, JP-A-58-1983)
No. 77861, Japanese Patent Application Laid-Open No. 60-248232,
JP-A-62-204940, JP-A-1-1080
37, etc.) have been proposed.

[0012]

However, the above-mentioned prior art has the following problems.

[0013] When a surface activation method such as corona discharge treatment is used to impart adhesiveness, although the effect of temporarily improving adhesiveness is obtained, it is not permanent and is not permanent. The effect is low level.

On the other hand, when an adhesive resin such as an acrylic resin, a urethane resin, or a polyester resin is provided as a primer layer, the adhesiveness is improved, but the storage and use under the above-described various environments are difficult. A remarkable decrease in adhesion is observed. In particular, conditions that are disadvantageous to the adhesive strength, for example, a situation in which the adhesiveness is insufficient under high temperature and high humidity often occur.

The present invention solves these drawbacks and improves the adhesiveness with a lens layer comprising a large number of lens units provided on a thermoplastic resin film, and at the same time, under various environments, particularly at high temperature and high humidity. It is an object of the present invention to provide a film for a lens sheet which has improved adhesiveness underneath and has excellent durability.

[0016]

According to the present invention, there is provided a lens sheet film which is provided adjacent to one surface of a lens layer and constitutes a lens sheet, comprising a thermoplastic resin film. And a laminated film comprising at least one of an amide ester bond, a urethane bond, an amide bond and a urea bond is provided on at least one surface of the film on the lens layer side. Film.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The thermoplastic resin film referred to in the present invention is:
It is a general term for films that are melted or softened by heat, and are not particularly limited, but typical examples are polyester films, polycarbonate films, acrylic films such as polymethyl methacrylate films and polystyrene films, and polypropylene films. Polyolefin films such as polyethylene and polyethylene films, polyamide films such as nylon, polyvinyl chloride films, polyurethane films, and fluorine-based films can be used.

These may be homopolymers or copolymers. Among these, in terms of mechanical strength, dimensional stability, transparency, and the like, polyester films, polycarbonate films, acrylic films, polyamide films, and the like are preferable, and further, adhesiveness with a laminated film provided on the film. In this respect, polyester films and polycarbonate films are preferable, and in terms of versatility, polyester films are particularly preferable.

In the polyester film according to the lens sheet film of the present invention, polyester is a generic term for polymers having an ester bond as a main bonding chain of a main chain. Preferred polyesters include ethylene terephthalate and propylene terephthalate. , Ethylene-2,
At least one component selected from 6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α, β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate; What is used as a main component can be used. These constituents may be used alone or in combination of two or more. Among them, it is particularly preferable to use a polyester having ethylene terephthalate as a main constituent when quality, economy and the like are comprehensively judged. . Further, in applications where heat acts on the base material, particularly in applications where a heat source such as a light source is used, or in cases where the resin constituting the lens is shrunk during formation of the lens layer, heat resistance and rigidity are high. Polyethylene-2,6-naphthalate, which is excellent in water resistance, is more preferable.

Further, these polyesters may further contain some other dicarboxylic acid component or diol component, preferably
0 mol% or less may be copolymerized.

The polyester further contains various additives such as antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, and fillers. , An antistatic agent, a nucleating agent and the like may be added to such an extent that their properties are not deteriorated.

The intrinsic viscosity of the above-mentioned polyester (25 ° C.)
Measured in o-chlorophenol of 0.4-1.2 d
l / g is preferable, and more preferably 0.5 to 0.8 dl.
/ G is suitable for carrying out the present invention.

The polyester film using the above polyester is preferably biaxially oriented when the laminated film is provided. The biaxially oriented polyester film generally means an unstretched polyester sheet or film in the longitudinal direction and the width direction.
It is stretched about 5 to 5 times, and then heat-treated to complete crystal orientation, and indicates a biaxially oriented pattern by wide-angle X-ray diffraction.

The thickness of the polyester film is not particularly limited, and is appropriately selected depending on the use in which the film for a lens sheet of the present invention is used. ~ 500μ
m, preferably 5 to 300 μm, more preferably 30 to 300 μm.
210 μm. Further, the obtained films can be used by being bonded by various methods.

In the present invention, the laminated film means a film-like film which is formed in a laminated structure on the surface of a thermoplastic resin film as a substrate. The film itself may be a single layer or a multilayer.

In the laminated film according to the present invention, the laminated film has an amide ester bond, a urethane bond, an amide bond,
It is necessary to contain at least one kind of urea bond.

The method for incorporating the bond into the laminated film is not particularly limited. For example, a laminated film comprising a compound having the bond may be provided, or a resin having a crosslinkable functional group and a crosslinking agent may be used. In a combination or a combination of resins having a crosslinkable functional group, a method of providing a laminated film having the bond by a crosslinking reaction can be used. In particular, a method of combining a resin having a crosslinkable functional group and a crosslinking agent and providing a laminated film having the bond by a crosslinking reaction is based on the improvement of crosslinking density by using a crosslinking agent.
Since the laminated film is excellent in strength and water resistance and also has good adhesiveness, it can be more suitably used.

As a combination of functional groups for obtaining each bond, a reaction between a carboxylic acid group and an oxazoline group can be used to obtain an amide ester bond, and a reaction between a hydroxyl group and an isocyanate group can be used for obtaining a urethane bond. For example, a reaction between a carboxylic acid group and an isocyanate group or a reaction between a carboxylic acid and an imino group can be used to obtain an amide bond, and a reaction between an amino group and an isocyanate group to obtain a urea bond. Etc. can be used, but it is not limited to these reactions.

The above-mentioned crosslinkable functional groups such as a carboxylic acid group, a hydroxyl group, an amino group, an oxazoline group, an isocyanate group, and an imino group can be used, for example, by acrylic resin, polyester resin, urethane resin, polyolefin resin, polycarbonate resin, alkyd resin, Epoxy resin, urea resin, phenol resin, vinyl chloride resin, vinyl acetate resin, fluororesin, silicone resin, rubber-based resin, can be used by introducing into a resin such as a wax-based resin, as a method of introducing, A method of copolymerizing the monomer having the crosslinkable functional group with the resin described above can be suitably used. Furthermore, in the present invention, at least one selected from the above-mentioned resins can be used.

Among them, it is preferable to use an acrylic resin, a polyester resin, or a urethane resin in view of the adhesiveness to the base film and the adhesiveness to the lens layer.
Kinds of resins, for example, acrylic resin and polyester resin,
It is more preferable to use a combination of an acrylic resin and a urethane resin, or a combination of a polyester resin and a urethane resin, because both characteristics are exhibited and the adhesiveness is improved.

In the film for a lens sheet of the present invention, the acrylic resin used as a component of the laminated film has a crosslinkable functional group such as a carboxylic acid group, a hydroxyl group, an amino group, an oxazoline group, an isocyanate group and an imino group. What is necessary is just to contain in the copolymerization monomer of resin.

The monomer components constituting the acrylic resin include, for example, alkyl acrylate and alkyl methacrylate (the alkyl group is a methyl group, an ethyl group,
n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), 2-hydroxy Ethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-
Hydroxy group-containing monomers such as hydroxypropyl methacrylate, acrylamide, methacrylamide, N
Amide groups such as -methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide Monomer, amino group-containing monomer such as N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, epoxy group-containing monomer such as glycidyl acrylate, glycidyl methacrylate, acrylic acid, methacrylic acid and salts thereof (lithium salt, And a monomer containing a carboxyl group or a salt thereof such as a sodium salt or a potassium salt.
Copolymerized using more than one species. Further, they can be used in combination with other types of monomers.

Other monomers include, for example, epoxy group-containing monomers such as allyl glycidyl ether and sulfones such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.). Monomers containing acid groups or salts thereof, crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salts, sodium salts,
Monomers containing a carboxyl group or a salt thereof, such as potassium salts and ammonium salts), maleic anhydride,
Monomers containing acid anhydrides such as itaconic anhydride, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacryloyl Nitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, vinyl chloride, and the like can be used.

As the acrylic resin that can be used in the present invention, a modified acrylic copolymer, for example, a block copolymer or a graft copolymer modified with polyester, urethane, epoxy or the like is also possible.

The glass transition point (Tg) of the acrylic resin used in the present invention is not particularly limited, but is preferably 0 to 90 ° C., more preferably 10 to 80 ° C.
° C. When an acrylic resin having a low Tg is used, the adhesiveness under high temperature and high humidity tends to be inferior. On the contrary, when it is too high, a crack may be generated during stretching, which is not preferable. Further, the molecular weight of the acrylic resin is preferably 100,000 or more,
More preferably, it is more than 300,000 from the viewpoint of adhesiveness.

Preferred acrylic resins used in the present invention include copolymers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, glycidyl methacrylate and acrylic acid. It is.

In producing the polyester film provided with the laminated film according to the present invention, a method of applying an aqueous resin coating solution to the polyester film before the completion of the crystal orientation, stretching and heat-treating to complete the crystal orientation. However, it is particularly preferable because heat treatment at a high temperature is possible and a more uniform and thin laminated film can be obtained. In the case of forming a laminated film by the above method, an acrylic resin which is soluble, emulsified, or suspended in water is preferable in terms of environmental pollution and explosion-proof properties. Such an aqueous acrylic resin may be copolymerized with a monomer having a hydrophilic group (such as acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid, or a salt thereof), emulsion-polymerized using a reactive emulsifier or a surfactant, and suspended. It can be prepared by a method such as turbid polymerization or soap-free polymerization.

In the lens sheet film of the present invention, the polyester resin used as a component of the laminated film has an ester bond in a main chain or a side chain and is obtained by polycondensation from a dicarboxylic acid and a diol. Yes, it is only necessary that the polyester resin contains a crosslinkable functional group such as a carboxylic acid group, a hydroxyl group, an amino group, an oxazoline group, an isocyanate group, and an imino group.

As the carboxylic acid component constituting the polyester resin, aromatic, aliphatic and alicyclic dicarboxylic acids and trivalent or higher polycarboxylic acids can be used. As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2 −
Bisphenoxyethane-p, p'-dicarboxylic acid, phenylindanedicarboxylic acid and the like can be used.
These aromatic dicarboxylic acids are preferably at least 30 mol%, more preferably at least 35 mol%, most preferably at least 4 mol% of the total dicarboxylic acid components in view of the strength and heat resistance of the laminated film.
It is preferable to use one having 0 mol% or more. Aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid,
Sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-
Cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like, and ester-forming derivatives thereof can be used.

The glycol component of the polyester resin includes ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3
-Butanediol, 1,4-butanediol, 1,5-
Pentanediol, 1,6-hexanediol, 1,7
-Heptanediol, 1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol, 2,
4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3 -Methyl-1,5
-Pentanediol, 2,2,4-trimethyl-1,6
-Hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-
Cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A, 4,4′-methylenediphenol, 4,4 ′-(2 -Norbornylidene)
Diphenol, 4,4′-dihydroxybiphenol,
o-, m-, and p-dihydroxybenzene, 4,
4′-isopropylidenephenol, 4,4′-isopropylidenebindiol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol and the like can be used.

When the polyester resin is used as a coating liquid containing an aqueous resin, a compound containing a sulfonate group or a carboxylic acid group may be used to improve the adhesion of the polyester resin or to make the polyester resin water-soluble. It is preferable to copolymerize a compound containing an acid base.

Examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, ,
2,3,4-butanetetracarboxylic acid, 1,2,3,4
-Pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-
1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid,
1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimellitate, 2,2 ', 3,3'
-Diphenyltetracarboxylic acid, thiophene-2,3
4,5-Tetracarboxylic acid, ethylenetetracarboxylic acid and the like, or alkali metal salts, alkaline earth metal salts and ammonium salts thereof can be used, but are not limited thereto.

Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid,
4-sulfoisophthalic acid, 4-sulfonaphthalene-2,
7-dicarboxylic acid, sulfo-p-xylylene glycol, 2-sulfo-1,4-bis (hydroxyethoxy)
Benzene or the like, or an alkali metal salt, an alkaline earth metal salt, or an ammonium salt thereof can be used, but is not limited thereto.

In the present invention, as the polyester resin that can be used, a modified polyester copolymer, for example, a block copolymer or a graft copolymer modified with acryl, urethane, epoxy or the like is also possible.

Preferred polyester resins include terephthalic acid, isophthalic acid, sebacic acid and
-Sodium sulfoisophthalic acid, trimellitic acid, pyromellitic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1,2
A dicarboxylic acid, and a copolymer selected from ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentyl glycol as a glycol component.

The polyester resin used for the laminated film according to the lens sheet film of the present invention can be produced by the following production method. For example, a polyester resin composed of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as a dicarboxylic acid component and ethylene glycol and neopentyl glycol as a glycol component is described. Terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene Glycol or neopentyl glycol, or a first step of transesterifying terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene glycol or neopentyl glycol, and a reaction of the first step It can be produced by a method of producing the product by a second step of performing a polycondensation reaction, or the like.

At this time, as a reaction catalyst, for example, an alkali metal, an alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, a titanium compound or the like can be used.

As a method for obtaining a polyester resin having a large amount of carboxylic acid at the terminal and / or side chain,
JP-A-54-46294, JP-A-60-2090
No. 73, JP-A-62-240318, JP-A-53-26828, JP-A-53-26829, JP-A-53-98336, JP-A-56-11
No. 6,718, JP-A-61-124684, JP-A-62-240318, etc. can be produced with a resin obtained by copolymerizing a trivalent or higher polycarboxylic acid. It may be a method.

The intrinsic viscosity of the polyester resin used in the laminated film according to the present invention is not particularly limited, but is preferably 0.3 dl / g or more from the viewpoint of adhesiveness.
It is more preferably at least 0.35 dl / g, most preferably at least 0.4 dl / g. Glass transition point of aqueous polyester resin (hereinafter abbreviated as "Tg")
Is preferably 0 to 90 ° C, more preferably 10 to 80 ° C. If the Tg is less than 0 ° C., the moisture-resistant adhesiveness is inferior. If the Tg exceeds 90 ° C., on the contrary, the film-forming property of the resin is inferior. The acid value of the water-based polyester resin is preferably 20 mgKOH / g or more, more preferably 30 mgKOH / g or more, in view of adhesiveness, particularly moisture resistance adhesiveness.

In the laminated film according to the present invention, particularly, as a resin, a glass transition point (hereinafter abbreviated as “Tg”) is used.
Of two types of polyester resins having different T
The Tg of the polyester resin having a high g is 60 ° C. or more and 11
0 ° C. or lower, Tg of polyester resin having low Tg
However, it has been found that by setting the temperature to less than 60 ° C., it is possible to obtain an extremely good adhesion to the lens layer.

At this time, if the polyester resin used satisfies the above-mentioned Tg, the same copolymer components such as the above-mentioned dicarboxylic acid component and diol component constituting the two different types of polyester resins are used. be able to.

According to the findings of the present inventors, the Tg of a polyester resin having a high Tg in terms of adhesiveness under high temperature and high humidity conditions.
Is preferably 65 ° C. or more and 100 ° C. or less,
More preferably, it is 70 ° C or more and 90 ° C or less. Also,
The Tg of the polyester resin having a low Tg is preferably -10 ° C or more and 50 ° C or less, more preferably 0 ° C or more and 4 ° C or less, from the viewpoint of adhesion and blocking resistance under normal conditions.
0 ° C. or less.

In the present invention, it is particularly preferred that 1,4-butanediol, neopentyl glycol and polyethylene glycol are copolymerized as the diol component of the polyester resin having a low Tg. It is preferably polymerized.
In addition, sebacic acid, adipic acid, and azelaic acid are preferably copolymerized as a dicarboxylic acid component from the viewpoint of adhesiveness.

The copolymerization ratio of neopentyl glycol in the diol component is preferably 35 to 90 mol%, more preferably 40 to 70 mol%.

The copolymerization of polyethylene glycol is effective for making the polyester resin water-soluble.
Among them, those having a molecular weight of 600 to 20,000 are preferable, more preferably 1000 to 6000, and the copolymerization ratio is preferably 0.2 to 10 mol% in the diol component, more preferably 0.4 to 5 mol%. Mol%. Further, since the above-mentioned copolymerization ratio changes greatly depending on the molecular weight of polyethylene glycol even if the copolymerization ratio is the same, the copolymerization amount of polyethylene glycol is preferably 1 to 20% by weight in terms of% by weight in the polyester resin. , More preferably 2 to 15% by weight.

In the lens sheet film of the present invention, the urethane resin used as a component of the laminated film is not particularly limited as long as it is a water-soluble or water-dispersible urethane resin having an anionic group. The component is obtained by copolymerizing a polyol and a polyisocyanate. Although the urethane resin has a urethane bond, in the present invention,
Carboxylic acid group, hydroxyl group, amino group, oxazoline group, isocyanate group, by including a crosslinkable functional group such as an imino group in the copolymerizable monomer of the urethane resin,
Further, it is preferable because the adhesiveness is improved.

As the urethane resin, those whose affinity for water is increased by a carboxylic acid group, a sulfonic acid group, or a sulfuric acid half ester base can be used. The content of a carboxylate group, a sulfonate group, a sulfuric acid half ester base or the like is preferably 0.5 to 15% by weight.

Examples of the polyol compound include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene glycol, hexamethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, and triethylene glycol. , Polycaprolactone, polyhexamethylene adipate, polytetramethylene adipate, trimethylolpropane, trimethylolethane, glycerin,
An acrylic polyol or the like can be used.

As the polyisocyanate compound, for example, tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, an adduct of hexamethylene diisocyanate and trimethylolethane, and the like can be used. Can be.

Here, the main constituent components of the urethane resin may contain a chain extender, a crosslinking agent and the like in addition to the above-mentioned polyol compound and polyisocyanate compound.

As a chain extender or a crosslinking agent, ethylene glycol, propylene glycol, butanediol, diethylene glycol, ethylenediamine, diethylenetriamine and the like can be used.

Examples of the urethane resin having an anionic group include a method using a compound having an anionic group as a polyol, a polyisocyanate, a chain extender, etc., and a method having an unreacted isocyanate group and an anionic group in the formed urethane resin. It can be produced by a method of reacting a compound, a method of reacting a group having an active hydrogen of a urethane resin with a specific compound, and the like, but is not particularly limited.

Further, a resin comprising a polyol having a molecular weight of 300 to 20,000, a polyisocyanate, a chain extender having a reactive hydrogen atom, a compound having a group which reacts with an isocyanate group, and a compound having at least one anionic group is preferable.

The anionic group in the urethane resin is preferably used as a sulfonic acid group, a carboxylic acid group, or an ammonium salt, a lithium salt, a sodium salt, a potassium salt or a magnesium salt thereof.
It is a sulfonate group.

The amount of the anionic group in the polyurethane resin is preferably 0.05% by weight to 8% by weight. If the amount is less than 0.05% by weight, the water dispersibility of the urethane resin tends to deteriorate, and if it exceeds 8% by weight, the water resistance and the blocking resistance of the resin tend to deteriorate.

In the laminated film according to the present invention, it has been found that the adhesiveness under high temperature and high humidity is improved by using the above-mentioned resin having a crosslinkable functional group in combination with a crosslinking agent which undergoes a crosslinking reaction. In particular, it is preferable to use a resin selected from at least one of an acrylic resin, a polyester resin, and a urethane resin in combination with a crosslinking agent as the resin used for the laminated film.

The crosslinking agent to be used is not particularly limited as long as it can react with a functional group present in the resin, for example, a hydroxyl group, a carboxyl group, a methylol group, an amide group and the like. , Melamine-based crosslinking agents, oxazoline-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, epoxy-based crosslinking agents, methylolated or alkylolated urea-based, acrylamide-based, polyamide-based resins, various silane coupling agents, various types Titanate-based coupling agents and the like can be used. In particular, those which form an amide ester bond, a urethane bond, an amide bond, or a urea bond by a crosslinking reaction are preferable in the present invention.

Among the crosslinking agents used, melamine-based crosslinking agents, oxazoline-based crosslinking agents, isocyanate-based crosslinking agents, aziridine-based crosslinking agents, and epoxy-based crosslinking agents are preferred in terms of crosslinking properties and adhesiveness. It has been found that by using an agent and an oxazoline-based crosslinking agent together, the adhesiveness under normal conditions is improved, and at the same time, the adhesiveness under high temperature and high humidity is dramatically improved.

The melamine cross-linking agent used in the present invention is not particularly limited, but is partially or completely reacted by reacting a lower alcohol with melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, or a methylolated melamine to partially or completely react. Etherified compounds or mixtures thereof can be used. In addition, as the melamine-based cross-linking agent, a monomer, a condensate composed of a multimer of a dimer or more, or a mixture thereof can be used. As the lower alcohol used for the etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be used. The functional group has an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule, and includes an imino group-type methylated melamine resin, a methylol group-type melamine resin, and a methylol group-type. Methylated melamine resins, fully alkylated methylated melamine resins, and the like. Among them, an imino group type melamine resin and a methylolated melamine resin are preferable, and an imino group type melamine resin is most preferable. Further, an acidic catalyst such as p-toluenesulfonic acid may be used in order to promote the thermal curing of the melamine-based crosslinking agent.

The oxazoline-based crosslinking agent used in the present invention is not particularly limited as long as it has an oxazoline group as a functional group in the compound, but it contains at least one or more oxazoline group-containing monomers. Those comprising an oxazoline group-containing copolymer are preferred.

Examples of such oxazoline-based crosslinking agents include JP-A-2-60941, JP-A-2-99537, JP-A-2-115238, and JP-B-63-48.
The copolymer described in JP-A-884 or the derivative thereof can be used.

Specifically, the following general formula (1)

Embedded image (Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, halogen, alkyl, aralkyl, phenyl or substituted phenyl group, and R ₅ is a noncyclic organic compound having an addition-polymerizable unsaturated bond. And a copolymer obtained by copolymerizing an addition-polymerizable oxazoline represented by the formula (1) with at least one other monomer.

Examples of the addition-polymerizable oxazoline include 2-vinyl-2-oxazoline and 2-vinyl-4-methyl-2.
-Oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-
Isopropenyl-4-methyl-2-oxazoline, 2-
Isopropenyl-5-ethyl-2-oxazoline and the like can be used, and one or a mixture of two or more thereof can also be used. Among them, 2-isopropenyl-2-oxazoline is preferable because it is easily available industrially.

In the oxazoline-based crosslinking agent, the at least one other monomer used for the addition-polymerizable oxazoline is not particularly limited as long as it is a monomer copolymerizable with the addition-polymerizable oxazoline. Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate,
Acrylic acid esters such as methacrylic acid-2-ethylhexyl or methacrylic acid esters, acrylic acid,
Unsaturated carboxylic acids such as methacrylic acid, itaconic acid and maleic acid, unsaturated nitriles such as acrylonitrile and methacrylonitrile, unsaturated amides such as acrylamide, methacrylamide, N-methylolacrylamide and N-methylolmethacrylamide, acetic acid vinyl,
Vinyl esters such as vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, olefins such as ethylene and propylene, vinyl chloride, vinylidene chloride, and halogen-containing α-, β-unsaturated monomers such as vinyl fluoride; Α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene can be used, and one or a mixture of two or more thereof can also be used.

In order to obtain an oxazoline-based crosslinking agent using addition-polymerizable oxazoline and at least one other monomer, polymerization may be carried out by an emulsion polymerization method, a solution polymerization method or the like.

For example, in the emulsion polymerization method, a polymerization catalyst, water,
Various methods such as a method in which a surfactant and a monomer are mixed at a time and polymerization, or a monomer dropping method, a multi-stage polymerization method, a pre-emulsion method and the like can be used. Polymerization catalysts include, for example, benzoyl peroxide, t-butyl hydroperoxide, azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, ammonium persulfate, 2,2 ′
-A radical polymerization initiator such as azobis (2-amidinopropane) dihydrochloride can be used. As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a reactive surfactant, or the like can be used. The polymerization temperature is usually 0 to 100 ° C, preferably 50 to 80 ° C, and the polymerization time is usually 1 to 10 ° C.
Time.

In the solution polymerization method, usable solvents include toluene, hexane, methyl ethyl ketone, ethyl cellosolve, methyl cellosolve, ethyl acetate, isopropyl alcohol, propylene glycol monomethyl ether and the like. Can also be used. Examples of the polymerization initiator used include azobisisobutyronitrile and benzoyl peroxide. The polymerization temperature is from 20 to 200C, preferably from 40 to 120C.

In obtaining an oxazoline-based cross-linking agent by using an addition-polymerizable oxazoline and another monomer, the amount of the addition-polymerizable oxazoline used is 0.5 to 8 in all monomers.
There is no particular limitation as long as it is in the range of 0% by weight or more. If the amount of the addition-polymerizable oxazoline is less than 0.5% by weight, the crosslinking effect due to the oxazoline group is small, and the adhesiveness tends to be poor. If it exceeds 80% by weight, the affinity with other resins used in combination and the crosslinking agent It tends to be poor in its own polymerizability.

The oxazoline-based crosslinking agent thus obtained is obtained, for example, in the form of an aqueous dispersion by an emulsion polymerization method and in the form of an organic solvent liquid by a solution polymerization method.
Any of these can be used as it is as a coating liquid for forming a laminated film. In addition, a solution obtained by a solution polymerization method can also be used as a pseudo-aqueous coating liquid by a method such as addition of water as long as it is an aqueous organic solvent. In particular, the resin obtained in this manner is, when used in combination with another resin, for example, an aqueous resin, from the form of the aqueous dispersion obtained by the emulsion polymerization method, the resin used in the present invention. Is preferred because the affinity of the compound becomes higher and the crosslinking effect becomes remarkably higher.

In the laminated film according to the present invention, the resin and the cross-linking agent can be mixed and used at an arbitrary ratio.
In order to more remarkably exert the effects of the present invention, the crosslinking agent is
Addition of 0.2 to 20 parts by weight to the resin is preferred from the viewpoint of improving adhesion under normal conditions, more preferably 0.5 to 15 parts by weight, and most preferably 1 to 10 parts by weight. When the addition amount of the crosslinking agent is less than 0.2 parts by weight, the effect of the addition is small, and when it exceeds 20 parts by weight, the adhesiveness tends to decrease.

Further, it should be particularly noted in the present invention that the melamine-based crosslinking agent and the oxazoline-based crosslinking agent are in the above-mentioned ranges, and their addition ratios ([oxazoline-based crosslinking agent]
/ [Melamine-based cross-linking agent], parentheses indicate the added weight of each cross-linking agent) of 0.1 to 10 has a remarkable effect on adhesiveness under high temperature and high humidity. . According to the knowledge of the present inventors, the addition weight ratio is 0.5 to
By setting it to 5, the adhesiveness particularly under high temperature and high humidity becomes excellent.

In the laminated film, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, an organic lubricant, and the like are used as long as the effects of the present invention are not impaired.
Pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents and the like may be blended.

In particular, those in which inorganic particles are added to the laminated film are more preferable because the lubricity and blocking resistance are improved.

In this case, as the inorganic particles to be added, silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate and the like can be used. The inorganic particles used have an average particle size of 0.0
1-5 μm is preferable, and more preferably 0.05-3 μm
m, most preferably 0.08 to 2 μm, and the mixing ratio with respect to the resin in the laminated film is not particularly limited, but is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 3 parts by weight in terms of solid content weight ratio. Parts by weight.

In producing the film for a lens sheet of the present invention, the most preferable method for providing a laminated film is a method in which the film is applied during the production process of a polyester film and stretched together with the base film. For example, the melt-extruded polyester film before crystal orientation is stretched about 2.5 to 5 times in the longitudinal direction, and a coating liquid is continuously applied to the uniaxially stretched film. The applied film is dried while passing through a stepwise heated zone, and is stretched about 2.5 to 5 times in the width direction. Furthermore, it can be obtained by a method (inline coating method) in which the crystal orientation is completed by being continuously guided to a heating zone at 150 to 250 ° C. The coating solution used in this case is preferably an aqueous solution from the viewpoint of environmental pollution and explosion-proof properties.

In the present invention, before applying the coating liquid,
The surface of the base film (in the case of the above example, a uniaxially stretched film) is subjected to a corona discharge treatment or the like, and the wet tension of the base film surface is preferably at least 47 mN / m, more preferably at least 50 mN / m. This is preferable because the adhesion of the laminated film to the base film can be improved.

Although the thickness of the laminated film is not particularly limited, it is usually preferably in the range of 0.01 to 5 μm, more preferably 0.02 to 2 μm, and most preferably 0.05 to 0.
5 μm. If the thickness of the laminated film is too small, poor adhesion may occur.

The method of coating on the substrate film uses various coating methods, for example, a reverse coating method, a gravure coating method, a rod coating method, a bar coating method, a Meyer bar coating method, a die coating method, a spray coating method and the like. be able to.

The lens layer according to the present invention can be used without any particular limitation as long as the lens unit has a lens surface formed in parallel. As the shape of the lens unit to be formed, various shapes can be used depending on the purpose. For example, a prism shape, a lenticular shape, and a waveform shape are preferable.

The material constituting the lens layer is not particularly limited, as long as it can transmit visible light. However, from the viewpoint of luminance, a material having high visible light transmittance is preferable. Examples of the material used include an acrylic resin, a polycarbonate resin, a vinyl chloride resin, and an actinic radiation curable resin. In particular, the actinic radiation curable resin has abrasion resistance,
It can be suitably used in terms of productivity and the like.

In the lens sheet film of the present invention, the actinic ray-curable resin used as a constituent component of the lens layer includes, for example, bis (methacryloylthiophenyl) as a monomer component constituting the actinic ray-curable resin. Sulfide, 2,4-dibromophenyl (meth) acrylate, 2,3,5-tribromophenyl (meth) acrylate, 2,2-bis (4- (meth) acryloyloxyphenyl) propane, 2,2-bis ( 4- (meth) acryloyloxyethoxyphenyl) propane, 2,2
-Bis (4- (meth) acryloyloxydiethoxyphenyl) propane, 2,2-bis (4- (meth) acryloylpentaethoxyphenyl) propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3) , 5
-Dibromophenyl) propane, 2,2-bis (4-
(Meth) acryloyloxydiethoxy-3,5-dibromophenyl) propane, 2,2-bis (4- (meth)
Acryloyloxypentaethoxy-3,5-dibromophenyl) propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3,5-dimethylphenyl)
Propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3-phenylphenyl) propane, bis (4- (meth) acryloyloxyphenyl) sulfone, bis (4- (meth) acryloyloxyethoxyphenyl) sulfone , Bis (4- (meth) acryloyloxypentaethoxyphenyl) sulfone, bis (4-
(Meth) acryloyloxyethoxy-3-phenylphenyl) sulfone, bis (4- (meth) acryloyloxyethoxy-3,5-dimethylphenyl) sulfone,
Bis (4- (meth) acryloyloxyphenyl) sulfide, bis (4- (meth) acryloyloxyethoxyphenyl) sulfide, bis (4- (meth) acryloyloxypentaethoxyphenyl) sulfide, bis (4- (meth) acryloyl) Oxyethoxy-3-phenylphenyl) sulfide, bis (4- (meth) acryloyloxyethoxy-3,5-dimethylphenyl) sulfide, di ((meth) acryloyloxyethoxy)
Polyfunctional (meth) acrylic compounds such as phosphate and tri ((meth) acryloyloxyethoxy) phosphate can be used.
More than one species is used.

In addition to these polyfunctional (meth) acrylic compounds, styrene, chlorostyrene, dichlorostyrene, bromostyrene, dibromostyrene are used to control the hardness, transparency, strength, refractive index, etc. of the active ray-curable resin. , Divinylbenzene, vinyltoluene,
1-vinylnaphthalene, 2-vinylnaphthalene, N-vinylpyrrolidone, phenyl (meth) acrylate, benzyl (meth) acrylate, biphenyl (meth) acrylate, diallyl phthalate, dimethallyl phthalate,
For example, diallyl biphenylate or a reaction product of a metal such as barium, lead, antimony, titanium, tin, and zinc with (meth) acrylic acid can be used. These are 1
Species or two or more species may be used.

In the present invention, the expression “(meth) acrylic compound” is an abbreviation for “methacrylic compound and acrylic compound”.
The same applies to other compounds.

As a method of curing the actinic ray-curable resin in the present invention, for example, a method of irradiating ultraviolet rays can be used. In this case, it is desirable to add a photopolymerization initiator to the compound. Examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichlorobenzophenone,
4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methylbenzoylformate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2,2- Dimethoxy-2-
Carbonyl compounds such as phenylacetophenone and 1-hydroxycyclohexylphenyl ketone; sulfur compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone; benzoyl peroxide; di-t-butyl Use a peroxide compound such as peroxide, or 2-hydroxy-2-methyl-1-phenylpropan-1-one, methylphenylglyoxylate, 2,4,6-trimethylbenzoylphosphine oxide, benzyldimethyl ketal, or the like. be able to. These photopolymerization initiators may be used alone or in combination of two or more.

The amount of the photopolymerization initiator used is suitably from 0.01 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer composition.

The actinic ray-curable resin used in the present invention includes hydroquinone, hydroquinone monomethyl ether, 2,2
A thermal polymerization inhibitor such as 5-t-butylhydroquinone can be added for use.

The amount of addition is preferably in the range of 0.005 to 0.05% by weight based on the total weight of the polymerizable compound.

The actinic radiation-curable resin which can be used in the present invention is provided for the purpose of improving workability at the time of coating and controlling the coating film thickness within a range where the intended effect of the present invention is not impaired. An organic solvent can be blended.

As the organic solvent, the boiling point is 50 to 150 ° C.
Are easy to use in terms of workability during coating and dryness before and after curing. Specific examples include alcohol solvents such as methanol, ethanol, and isopropyl alcohol; acetate solvents such as methyl acetate, ethyl acetate and butyl acetate; ketone solvents such as acetone and methyl ethyl ketone; and aromatic solvents such as toluene. And a cyclic ether-based solvent such as dioxane.
These solvents can be used alone or in combination of two or more.

In the lens layer, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a yellowing inhibitor and the like can be used as long as the effects of the present invention are not impaired. Organic lubricants, pigments, dyes, bluing agents, organic or inorganic fine particles, fillers, antistatic agents, surfactants, leveling agents, nucleating agents, diffusing agents, and the like may be blended.

The method of providing the actinic radiation-curable resin on the laminated polyester film is not particularly limited, and various methods can be employed depending on the required characteristics and intended use. For example, a method in which the resin is applied with a bar cut into a prism shape, or a method in which the resin is poured into a mold having a lens layer shape such as a prism shape, and a laminated polyester film is laminated, can be used.

In the present invention, actinic radiation means electromagnetic waves such as ultraviolet rays, electron beams, and radiations (α rays, β rays, γ rays, etc.) which polymerize an acrylic vinyl group. Is preferable. As the ultraviolet source, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc lamp, and the like can be used. In addition, the electron beam method is advantageous in that the apparatus is expensive and requires an operation under an inert gas, but it does not need to contain a photopolymerization initiator or a photosensitizer.

In the present invention, the thickness of the lens layer can be arbitrarily selected depending on the purpose of the lens sheet and the shape of the lens unit, and is not particularly limited.
It is preferably 5 mm, more preferably 0.2 to 3 mm. When the thickness is less than 0.1 mm, the effect as a lens layer tends to be lost, and when the thickness is more than 5 mm, the brightness tends to be insufficient.

The pitch of the lens unit can be appropriately selected according to the purpose of the lens sheet and the shape of the lens unit, and is not particularly limited. 0.03 to 0.5 mm,
More preferably, it is 0.05 to 0.3 mm.

In particular, it is preferable to use a prism sheet in which the lens layer has a prism shape in terms of brightness and ease of formation. In this case, the prism apex angle of the prism shape is preferable. Is preferably 80 to 150 degrees, more preferably 85 to 130 degrees.

In the present invention, it is preferable to provide an antireflection layer for suppressing flickering on the surface of the lens layer or to perform an antifouling treatment for preventing dirt. Although the antireflection layer is not particularly limited, it can be formed by laminating a low refractive index compound, or by sputtering an inorganic compound such as magnesium fluoride or silicon oxide. As for the antifouling treatment, an antifouling treatment using a silicone resin, a fluorine resin or the like can be performed.

Next, the method for producing the lens sheet film of the present invention will be described with reference to an example in which polyethylene terephthalate (hereinafter abbreviated as “PET”) is used as a base film, but the present invention is not limited to this. .

The lens sheet film of the present invention, which has excellent durability even under various environments, has a laminated film provided on at least one surface of a thermoplastic resin film.
In a lens sheet provided with a lens layer having a lens surface in which lens units are formed in parallel on the laminated film, the laminated film has an amide ester bond, a urethane bond,
It can be produced by containing at least one of an amide bond and a urea bond.

More specifically, for example, the limiting viscosity is 0.5
After vacuum drying of ~ 0.8 dl / g PET pellets,
It is supplied to an extruder, melted at 260 to 300 ° C., extruded from a T-shaped die into a sheet, wound around a mirror casting drum having a surface temperature of 10 to 60 ° C. using an electrostatic application casting method, and cooled and solidified. Create an unstretched PET film. This unstretched film is stretched 2.5 to 5 times in the longitudinal direction (the direction of film movement) between rolls heated to 70 to 120 ° C. At least one surface of the film is subjected to a corona discharge treatment, and the wetting tension of the surface is set to 47 mN.
/ M or more, and the treated surface is coated with the coating liquid for forming a laminated film according to the present invention. The coated film is gripped with a clip and guided to a hot air zone heated to 70 to 150 ° C.
After drying, the film is stretched 2.5 to 5 times in the width direction.
It is led to a heat treatment zone of 60 to 250 ° C. and heat treated for 1 to 30 seconds to complete the crystal orientation. During this heat treatment step, if necessary,
A relaxation treatment of １２12% may be performed. Biaxial stretching is vertical,
Either transverse sequential stretching or simultaneous biaxial stretching may be used, and after stretching in the longitudinal and transverse directions, the film may be stretched again in the longitudinal or transverse direction. The thickness of the polyester film is not particularly limited, but is preferably 5 to 300 μm. The coating liquid used in this case is preferably water-based in view of environmental pollution and explosion-proof properties.

In the above examples, the base film on which the laminated film is provided may contain at least one selected from melamine-based crosslinking agents, oxazoline-based crosslinking agents, and reaction products thereof. in this case,
There are effects such as improvement in the adhesion between the laminated film and the base film, and improvement in the lubricity of the laminated polyester film. When a melamine-based cross-linking agent, an oxazoline-based cross-linking agent, or a reaction product thereof is contained, the total amount of one or more of them may be 5 ppm or more and 20 or more.
It is preferable that the content is less than the weight% in terms of adhesiveness and lubricity. Of course, the melamine-based cross-linking agent, oxazoline-based cross-linking agent, or a reaction product thereof may be a laminated film-forming composition (including regenerated pellets of a laminated polyester film according to the present invention) provided on a base film. Good.

The film for a lens sheet of the present invention thus obtained is cut into a predetermined lens sheet size, and the above-mentioned active ray-curable resin is poured into a mold having a prism-shaped lens layer. It is superposed on the surface of the lens sheet film on which the laminated film is provided (however, when the laminated film is provided on both surfaces, any surface may be used) and irradiated with actinic rays such as ultraviolet rays to form an actinic ray-curable type. After curing the resin, the mold is removed to obtain a lens sheet.

The lens sheet is used, for example, to constitute a part of a backlight. In the backlight, a light source such as a fluorescent lamp is provided at one end of a light guide, and the light guide is The lens surface of the lens sheet of the present invention can be provided on the upper side with the lens surface facing upward.

[0114]

[Method for measuring characteristics and method for evaluating effects] The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.

(1) Thickness of Laminated Film The thickness was determined from a photograph obtained by observing the cross section of the laminated polyester film provided with the laminated film using a transmission electron microscope HU-12 manufactured by Hitachi, Ltd. The thickness was an average value of 30 pieces in the measurement visual field.

(2) Adhesiveness-1 A lens layer was provided on the lens sheet film of the present invention, 25 cross cuts of 2 mm ² were put on the lens layer, and a cellophane tape manufactured by Nichiban Co., Ltd. was placed thereon. pasting,
Using a rubber roller, reciprocate 3 times with a load of 19.6N,
After pressing, peeled in the direction of 90 degrees, and evaluated according to the 4-step evaluation based on the number of remaining print layers (（: 25, ：: 20 to 24,
Δ: 10 to 19, ×: 0 to 9). (◎) and (○) indicate good adhesiveness and excellent durability.

(3) Adhesion-2 The film for a lens sheet of the present invention provided with a lens layer was subjected to a high-temperature and high-humidity treatment (left standing at 95 ° C. for 1 hour in hot water). Immediately after the treatment, wipe off the moisture
After one minute, the same evaluation as in the above (2) was performed.

(4) Adhesion-3 The film for a lens sheet of the present invention provided with a lens layer was subjected to a high-temperature and high-humidity treatment (left in hot water at 80 ° C. for 3 hours). Immediately after the treatment, wipe off the moisture
After one minute, the same evaluation as in the above (2) was performed.

(5) Glass transition point (Tg) Robot DSC (differential scanning calorimeter) RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd. SSC manufactured by Seiko Denshi Kogyo Co., Ltd.
The measurement was performed with a 5200 disk station connected. D
The measurement conditions of SC are as follows. That is, the sample 10 mg
Is adjusted to an aluminum pan, then set in a DSC device (reference: aluminum pan of the same type without a sample), heated at 300 ° C. for 5 minutes, and then quenched in liquid nitrogen. This sample was heated at 10 ° C /
And the DSC chart Tg is detected.

[0120]

Next, the present invention will be described with reference to examples, but is not necessarily limited thereto.

Example 1 PET pellets containing 0.015% by weight of colloidal silica having an average particle diameter of 0.4 μm and 0.005% by weight of colloidal silica having an average particle diameter of 1.5 μm (intrinsic viscosity: 0.63 dl / g) ) Was sufficiently dried in a vacuum, fed to an extruder, melted at 285 ° C., extruded in a sheet shape from a T-shaped die, and cast at a surface temperature of 20 using an electrostatic application casting method.
It was wrapped around a mirror-surfaced casting drum at ℃ to be cooled and solidified.

The unstretched film was heated to 95 ° C. and stretched 3.5 times in the longitudinal direction to obtain a uniaxially stretched film. The film was subjected to a corona discharge treatment in air, the wet tension of the substrate film was set to 52 mN / m, and the following coating liquid for forming a laminated film was applied to the treated surface. While holding the applied uniaxially stretched film with a clip, the film is guided to a preheating zone, and 11
After drying at 0 ° C., the film is continuously stretched 3.5 times in the width direction in a heating zone at 125 ° C., and further subjected to a heat treatment in a heating zone at 225 ° C. to complete the crystal orientation of the film for a lens sheet of the present invention. Obtained. At this time, the thickness of the base PET film was 125 μm, and the thickness of the laminated film was 0.08 μm.

The obtained lens sheet film was cut into a predetermined lens sheet size. Then, the following active ray-curable resin is poured into a prism-shaped lens mold (lens pitch: 50 μm, prism apex angle: 95 degrees), and is superimposed on the surface on which the laminated film of the lens sheet film is provided. Irradiation was performed at an irradiation distance (distance between the lamp and the ink surface) of 9 cm for 10 seconds using an ultraviolet lamp of 10 cm / cm to cure the active ray-curable resin, and then removed from the lens mold to obtain a prism sheet. Table 1 shows the results.

"Coating Liquid for Forming Laminated Film" Acrylic resin-1: Methyl methacrylate 64% by weight Ethyl acrylate 30% by weight Acrylic acid 5% by weight Acrylonitrile 1% by weight An acrylic resin copolymer emulsion copolymerized with the above composition.

Melamine-based crosslinking agent: a coating solution obtained by diluting an imino group type methylated melamine in a mixed solvent (10/90 (weight ratio)) of isopropyl alcohol and water.

A coating liquid for forming a laminated film was prepared by adding 2 parts by weight of a melamine crosslinking agent to 100 parts by weight of the acrylic resin.

"Activation-ray-curable resin" Bis (methacryloylthiophenyl) sulfide 50 parts by weight 2,3,5-tribromophenyl methacrylate 30 parts by weight Trimethylolpropane triacrylate 20 parts by weight The above mixture was used as a photopolymerization initiator. 2-hydroxy-2
An actinic radiation-curable resin was obtained by adding 2 parts by weight of -methyl-1-phenylpropan-1-one.

Example 2 In the coating liquid for forming a laminated film of Example 1, the following acrylic resin was used as the resin, and "Prominate" X manufactured by Takeda Pharmaceutical Co., Ltd. was used as an isocyanate crosslinking agent instead of a melamine crosslinking agent.
A lens sheet was obtained in the same manner as in Example 1, except that 8 parts by weight of C-915 was used. Table 1 shows the results.

Acrylic resin-2: 60% by weight of methyl methacrylate 32% by weight of ethyl acrylate 6% by weight of 2-hydroxyethyl acrylate 2% by weight of acrylonitrile An acrylic resin copolymer emulsion copolymerized with the above composition.

Example 3 A lens sheet was prepared in the same manner as in Example 1 except that the following urethane resin was used as the resin for forming the laminated film of Example 1 and 5 parts by weight of a melamine crosslinking agent was used. Obtained. Table 1 shows the results.

Urethane resin: 192 parts by weight of polyether containing sodium sulfonate obtained by sulfonating polyether of ethylene oxide (sulfonic acid group content: 8% by weight), 1013 parts by weight of polytetramethylene adipate,
248 parts by weight of polypropylene oxide polyether were mixed, dehydrated at 100 ° C. under reduced pressure, the mixture was heated to 70 ° C., and a mixture of 178 parts by weight of isophorone diisocyanate and 244 parts by weight of hexamethylene-1,6-diisocyanate was added, The product mixture was further stirred at 80-90 ° C. until the isocyanate content was 5.6% by weight. The obtained prepolymer was cooled to 60 ° C., and bisketimine 173 obtained from 56 parts by weight of biuret polyisocyanate obtained from 3 moles of hexamethylene diisocyanate and 1 mole of water, isophoronediamine and acetone was used.
Parts by weight. Then, hydrazine hydrate 1
An aqueous solution at 50 ° C. in which 5 parts by weight was dissolved was added to this mixture with stirring to obtain a urethane resin aqueous dispersion.

Example 4 In the coating liquid for forming a laminated film of Example 3, 5 parts by weight of a crosslinking agent CR-5L manufactured by Dainippon Ink and Chemicals, Inc. was used as an epoxy crosslinking agent instead of a melamine crosslinking agent. A lens sheet was obtained in the same manner as in Example 3, except for the difference. Table 1 shows the results.

Example 5 A lens sheet was obtained in the same manner as in Example 1 except that the mixture of an acrylic resin and a polyester resin shown below was used as the resin in the coating liquid for forming a laminated film of Example 1. Table 1 shows the results.

Acrylic resin-1: Methyl methacrylate 64% by weight Ethyl acrylate 30% by weight Acrylic acid 5% by weight Acrylonitrile 1% by weight An acrylic resin copolymer emulsion copolymerized with the above composition.

Polyester resin-1: ・ Acid component 88% by mole of terephthalic acid 12% by mole of 5-sodium sulfoisophthalic acid ・ Diol component 99% by mole of ethylene glycol 1% by mole of diethylene glycol 1% by weight of water solubility of polyester resin composed of the above acid component and diol component Coating liquid.

With respect to 50 parts by weight of the acrylic resin and 50 parts by weight of the polyester resin, 100 parts by weight in total
What added the same melamine type crosslinking agent as Example 1 2 weight part was used as the coating liquid for lamination film formation.

Example 6 The procedure of Example 5 was repeated, except that the following oxazoline-based cross-linking agent was used in place of the melamine-based cross-linking agent in an amount of 5 parts by weight as the cross-linking agent. To obtain a lens sheet. Table 1 shows the results.

Oxazoline-based cross-linking agent: methyl methacrylate 60% by weight butyl acrylate 15% by weight styrene 5% by weight 2-isopropenyl-2-oxazoline 20% by weight The oxazoline group-containing resin composition copolymerized with the above composition is mixed with propylene glycol monomethyl A coating solution diluted in a mixed solvent of ether and water (20/80 (weight ratio)).

Example 7 Example 5 was repeated except that the following melamine-based crosslinking agent was added as a crosslinking agent in an amount of 2 parts by weight and an oxazoline-based crosslinking agent was added in an amount of 5 parts by weight. A lens sheet was obtained in the same manner as described above. Table 1 shows the results.

Melamine-based cross-linking agent: a coating solution obtained by diluting an imino group type methylated melamine in a mixed solvent (10/90 (weight ratio)) of isopropyl alcohol and water.

Oxazoline-based cross-linking agent: methyl methacrylate 60% by weight butyl acrylate 15% by weight styrene 5% by weight 2-isopropenyl-2-oxazoline 20% by weight The oxazoline group-containing resin composition copolymerized with the above composition is mixed with propylene glycol monomethyl. A coating solution diluted in a mixed solvent of ether and water (20/80 (weight ratio)).

Example 8 A lens sheet was obtained in the same manner as in Example 1, except that the following coating liquid for forming a laminated film was used. Table 1 shows the results.

“Laminated Film Forming Coating Liquid” Polyester Resin-1: Acid component 88 mol% terephthalic acid 12 mol% 5-sodium sulfoisophthalic acid Diol component Ethylene glycol 99 mol% Diethylene glycol 1 mol% The above acid component and diol component A water-soluble coating liquid of a polyester resin.

Polyester resin-2: acid component terephthalic acid 45 mol% isophthalic acid 32 mol% sebacic acid 20 mol% 5-sodium sulfoisophthalic acid 3 mol% diol component ethylene glycol 55 mol% neopentyl glycol 44 mol% polyethylene Glycol (molecular weight 4000) 1 mol% A polyester resin comprising the above-mentioned acid component and diol component was mixed with a mixture of t-butyl cellosolve and water (10/90
(Weight ratio)).

Melamine-based cross-linking agent: a coating solution obtained by diluting an imino group type methylated melamine in a mixed solvent (10/90 (weight ratio)) of isopropyl alcohol and water.

Oxazoline-based cross-linking agent: methyl methacrylate 60% by weight butyl acrylate 15% by weight styrene 5% by weight 2-isopropenyl-2-oxazoline 20% by weight The oxazoline group-containing resin composition copolymerized with the above composition is mixed with propylene glycol monomethyl A coating solution diluted in a mixed solvent of ether and water (20/80 (weight ratio)).

With respect to 60 parts by weight of the polyester resin-1 and 40 parts by weight of the polyester resin-2, 2 parts by weight of a melamine crosslinking agent and 5 parts by weight of an oxazoline crosslinking agent were added. This was used as a coating liquid for forming a laminated film.

Example 9 A lens was prepared in the same manner as in Example 8, except that 5 parts by weight of a melamine-based crosslinking agent and 2 parts by weight of an oxazoline-based crosslinking agent were added to the coating liquid for forming a laminated film of Example 8. I got a sheet. Table 1 shows the results.

Example 10 In Example 8, a PET pellet substantially free of external particles (intrinsic viscosity 0.63 dl) was used as the base film.
/ G) was used to obtain a lens sheet in the same manner as in Example 8.

The results are shown in Table 1. Further, since the transparency was excellent, it was advantageous in terms of luminance.

Example 11 A lens sheet was obtained in the same manner as in Example 8, except that the following active ray-curable resin was used as the active ray-curable resin. Table 1 shows the results.

"Activation-ray-curable resin" 2,2-bis (4-methacryloyloxy 55 parts by weight ethoxyphenyl) propane 2,4-dibromophenyl methacrylate 25 parts by weight Trimethylolpropane triacrylate 20 parts by weight 2-hydroxy-2 as a polymerization initiator
An actinic radiation-curable resin was obtained by adding 2 parts by weight of -methyl-1-phenylpropan-1-one.

Example 12 In Example 8, the polyester film was changed from polyethylene terephthalate film to polyethylene-2,6-
A lens sheet was obtained in the same manner as in Example 8, except that the film was changed to a naphthalate (hereinafter, abbreviated as "PEN") film. The results are shown in Table 1. Further, since the rigidity of the base material was high, the thermal deformation of the prism sheet due to the heat generated by the light source was extremely small, and the prism sheet was suitable as a film for a prism sheet.

Example 13 The same as Example 1 except that the laminated PET film obtained in Example 1 was pulverized and pelletized, and 20% by weight was added to polyethylene terephthalate and melt-extruded. To obtain a lens sheet. Table 1 shows the results.

Comparative Example 1 A lens sheet was obtained in the same manner as in Example 1, except that the coating liquid for forming a laminated film of Example 1 was used without adding a melamine-based crosslinking agent. Table 1 shows the results.

Comparative Example 2 A lens sheet was prepared in the same manner as in Example 1 except that the following polyester resin was used as the resin in the coating liquid for forming a laminated film of Example 1 and the melamine-based crosslinking agent was not used. Obtained.
Table 1 shows the results.

"Laminated film forming coating liquid" Polyester resin-2: Acid component Terephthalic acid 45 mol% Isophthalic acid 32 mol% Sebacic acid 20 mol% 5-Sodium sulfoisophthalic acid 3 mol% Diol component ethylene glycol 55 mol% Neopentyl glycol 44 mol% Polyethylene glycol (molecular weight 4000) 1 mol% The polyester resin composed of the acid component and the diol component was mixed with a mixture of t-butyl cellosolve and water (10/90).
(Weight ratio)).

Comparative Example 3 The same procedure as in Example 1 was carried out except that the resin used was not used but the oxazoline-based crosslinking agent used in Example 6 was used as the oxazoline-based crosslinking agent. A lens sheet was obtained. Table 1 shows the results.

[0159]

[Table 1]

[0160]

The film for a lens sheet of the present invention, when used as a lens sheet by using a laminated polyester film provided with a laminated film having a specific bond,
It has excellent adhesiveness to the lens layer, as well as excellent adhesiveness even after treatment under high temperature and high humidity, and exhibits excellent durability in various environments.

Claims (10)

[Claims] 1. A lens sheet film provided adjacent to one surface of a lens layer to constitute a lens sheet, comprising a thermoplastic resin film, and having at least one amide ester bond on at least one surface of the film on the lens layer side. A film for a lens sheet, comprising a laminated film containing at least one of a urethane bond, an amide bond and a urea bond. 2. The laminated film contains a crosslinker selected from at least one of a melamine crosslinker, an oxazoline crosslinker, an isocyanate crosslinker, an aziridine crosslinker, and an epoxy crosslinker. The film for a lens sheet according to claim 1, wherein: 3. The lens sheet film according to claim 1, wherein the thermoplastic resin film is a polyester film. 4. The lens sheet according to claim 1, wherein the laminated film contains a resin selected from at least one of an acrylic resin, a polyester resin, and a urethane resin. the film. 5. A cross-linking agent comprising a melamine cross-linking agent and an oxazoline cross-linking agent.
Or the film for a lens sheet according to 4. 6. In the laminated film, 0.2 to 20 parts by weight of a melamine-based crosslinking agent is added to the resin, 0.2 to 20 parts by weight of an oxazoline-based crosslinking agent is added to the resin, and the crosslinking agent is added. Weight ratio ([oxazoline-based crosslinking agent] /
The film for a lens sheet according to claim 1, 2, 3, 4, or 5, wherein [melamine-based cross-linking agent]) is 0.1 to 10. 7. The resin in the laminated film comprises two types of polyester resins having different glass transition points, and the polyester resin having a high glass transition point has a glass transition point of 60 ° C. or more and 110 ° C. or less, 7. The lens sheet film according to claim 1, wherein the polyester resin having a low glass transition point has a glass transition point of less than 60 ° C. 8. The method according to claim 1, wherein the polyester film is a polyethylene terephthalate film, a polypropylene terephthalate film, or a polyethylene-2,6-naphthalate film.
The film for a lens sheet according to 4, 5, 6, or 7. 9. A method of forming a laminated film, comprising applying a laminated film forming coating solution to at least one surface of a polyester film before crystal orientation is completed, and then stretching and heat-treating in at least one direction. Claims 1, 2, 3,
The film for a lens sheet according to 4, 5, 6, 7, or 8. 10. A polyester film comprising a composition containing a total of at least 5 ppm and less than 20% by weight of at least one selected from melamine-based crosslinking agents, oxazoline-based crosslinking agents, and reaction products thereof. Claim 1, 2, 3, 4, 5, 6, 7, 8, or 9
The film for a lens sheet according to the above.