JP2009185282A - Hard coat film and method of producing the same, optical element, and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film excellent in moisture barrier properties, heat resistance, gas barrier properties, and durability, and excellent in adhesion between its transparent plastic film substrate and its hard coat layer. <P>SOLUTION: The hard coat layer 12 is formed using a hard coat layer-forming material containing an (A) component: a polyol acrylate and polyol methacrylate, on at least one surface of a transparent plastic film substrate 11 containing at least one of an acrylic resin and a methacrylic resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hard coat film, a method for producing a hard coat film, an optical element, and an image display device.

  2. Description of the Related Art Conventionally, liquid crystal display devices (LCD) have been widely used for electronic devices used indoors such as personal computers and televisions. Recently, in addition to the indoor devices, LCDs are increasingly used for devices used outdoors such as car navigation systems and portable information terminals. Accordingly, LCDs are required to be reliable in harsh atmospheres such as high temperature and humidity.

  The basic structure of an LCD is that a glass substrate on a flat plate, each with a transparent electrode, is placed oppositely through a spacer so as to form a gap with a constant interval, and a liquid crystal material is injected between the glass substrates and sealed. The liquid crystal cell is further provided with polarizing plates on the outer surfaces of the pair of glass substrates. Conventionally, a cover plate made of glass or plastic is attached to the surface of the liquid crystal cell to prevent damage to the polarizing plate attached to the surface of the liquid crystal cell. However, when a cover plate is attached, it is disadvantageous in terms of cost and weight, and a hard coat treatment is gradually applied to the polarizing plate surface.

  For the hard coat treatment, for example, a transparent protective film made of a triacetyl cellulose (TAC) film is used. In the hard coat treatment, for example, a hard coat film in which a hard coat layer is formed on one side or both sides of the transparent protective film (transparent plastic film substrate) is also used. The hard coat layer is usually formed using a hard coat layer forming material such as a thermosetting resin or an ultraviolet curable resin.

  Here, the transparent protective film made of the TAC film is inferior in moisture resistance and heat resistance, and in a high temperature and humidity environment, for example, in an atmosphere of 80 ° C. and a relative humidity of 90%, the polarizing function of the polarizing plate is about 100 hours. Will be reduced. In addition, the transparent protective film made of the TAC film is inferior in gas barrier properties and easily changes the quality of the polarizing plate by the transmitted oxygen. Furthermore, in order to improve the strength and durability, it is necessary to use, for example, a TAC film having a thickness of 80 μm or more as the transparent protective film, which is one factor that hinders thinning of the LCD.

  For these problems, a transparent protective film containing at least one of an acrylic resin and a methacrylic resin has been proposed (see Patent Documents 1 to 3). This transparent protective film is excellent in moisture resistance, heat resistance, gas barrier property and durability as compared with the transparent protective film made of the TAC film. However, when the hard coat layer is formed on one surface or both surfaces of the transparent protective film (transparent plastic film substrate), the adhesion between the transparent plastic film substrate and the hard coat layer is poor.

International Publication No. WO2006 / 112207 Pamphlet International Publication No. WO2006 / 112223 Pamphlet JP 2007-140092 A

  Accordingly, an object of the present invention is to provide a hard coat film excellent in moisture resistance, heat resistance, gas barrier properties and durability, and excellent in adhesion between the transparent plastic film substrate and the hard coat layer, a method for producing the same, and It is to provide an optical element and an image display device used.

In order to achieve the above object, the hard coat film of the present invention is a hard coat film having a hard coat layer on at least one surface of a transparent plastic film substrate,
The transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin;
The hard coat layer is formed using a hard coat layer forming material containing the following component (A).
Component (A): at least one of polyol acrylate and polyol methacrylate

The production method of the present invention is a method for producing a hard coat film having a hard coat layer on at least one surface of a transparent plastic film substrate, and includes the following steps [1] to [4]. And
[1] Step of preparing a transparent plastic film substrate containing at least one of an acrylic resin and a methacrylic resin [2] A hard coat containing the following component (A) on at least one surface of the transparent plastic film substrate Step [3] for forming a coating film by applying a layer forming material [4] Step for drying the coating film [4] Step for curing the coating film after the step [3] and forming a hard coat layer Component (A): at least one of polyol acrylate and polyol methacrylate

  The optical element of the present invention is an optical element in which a hard coat film is disposed on at least one surface of an optical member, and the hard coat film is the hard coat film of the present invention.

  The image display device of the present invention is an image display device including a hard coat film or an optical element, wherein the hard coat film is the hard coat film of the present invention, and the optical element is the optical element of the present invention. It is characterized by that.

  The hard coat film of the present invention is excellent in moisture resistance, heat resistance, gas barrier property and durability because the transparent plastic film substrate contains at least one of acrylic resin and methacrylic resin. Moreover, the hard coat film of this invention is excellent in the adhesiveness of the said transparent plastic film base material and the said hard-coat layer because the said hard-coat layer forming material contains the said (A) component.

FIG. 1 is a schematic cross-sectional view showing an example of the hard coat film of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the hard coat film of the present invention.

  In the hard coat film of the present invention, the mechanism for improving the adhesion between the transparent plastic film substrate and the hard coat layer is estimated as follows, for example. That is, it is considered that the adhesion is improved by slightly eroding and dissolving the surface of the transparent plastic film substrate by the component (A) contained in the hard coat layer forming material. However, this mechanism is speculation and does not limit the present invention.

  In the hard coat film of the present invention and the method for producing the same, the component (A) preferably contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. This is because an excellent hard coat film can be obtained due to the adhesion between the transparent plastic film substrate and the hard coat layer.

In the hard coat film and the method for producing the same of the present invention, it is preferable that the hard coat layer forming material further includes the following components (B) and (C).
(B) component: at least one of urethane acrylate and urethane methacrylate (C) component: a polymer or copolymer formed from at least one of the following (C1) and (C2) below or a mixed polymer of the above polymer and copolymer (C1): hydroxyl group And an alkyl acrylate having an alkyl group having at least one of acryloyl groups (C2): an alkyl methacrylate having an alkyl group having at least one of a hydroxyl group and an acryloyl group. By including the component (B) and the component (C) in addition to the component A), it has sufficient hardness, prevents the occurrence of curling and folding due to the curing shrinkage of the hard coat layer, and improves the scratch resistance. To get an excellent hard coat film Because it can.

  In the hard coat film and the method for producing the same of the present invention, at least one of the pentaerythritol triacrylate and the pentaerythritol tetraacrylate with respect to a total of 100 parts by weight of the component (A), the component (B), and the component (C). Is preferably blended in the range of 15 to 50 parts by weight. That is, when the hard coat layer forming material contains any one of the pentaerythritol triacrylate and pentaerythritol tetraacrylate, the blending amount of one of them is the component (A), the component (B) and the component (C) It is preferable that it is the range of 15-50 weight part with respect to a total of 100 weight part of a component, and when the said hard-coat layer formation material contains both the said pentaerythritol triacrylate and pentaerythritol tetraacrylate. The total blending amount of both is preferably in the range of 15 to 50 parts by weight with respect to 100 parts by weight as the total of the component (A), the component (B) and the component (C).

前記式（１）において、Ｒ^１は、−Ｈまたは−ＣＨ_３であり、Ｒ^２は、−ＣＨ_２ＣＨ_２ＯＸ若しくは下記一般式（２）で表される基であり、前記Ｘは、−Ｈまたは下記一般式（３）で表されるアクリロイル基である。

前記式（２）において、２つのＸは、−Ｈまたは下記一般式（３）で表されるアクリロイル基であり、各Ｘは、同一でも異なっていてもよい。

In the hard coat film and the method for producing the same of the present invention, the component (C) preferably contains a polymer, a copolymer or a mixture of the polymer and the copolymer containing a repeating unit of the following general formula (1).

In the formula (1), R ¹ is —H or —CH ₃ , R ² is —CH ₂ CH ₂ OX or a group represented by the following general formula (2), and the X is — H or an acryloyl group represented by the following general formula (3).

In the formula (2), two Xs are —H or an acryloyl group represented by the following general formula (3), and each X may be the same or different.

  In the hard coat film and the method for producing the same of the present invention, the transparent plastic film substrate preferably contains at least one of an acrylic resin and a methacrylic resin having a lactone ring structure.

前記式（４）において、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ、水素原子または炭素原子数１〜２０の有機残基であり、前記Ｒ^１、前記Ｒ^２および前記Ｒ^３は、同一でも異なっていてもよい。 In the hard coat film and the method for producing the same of the present invention, the transparent plastic film substrate preferably contains at least one of an acrylic resin and a methacrylic resin having a lactone ring structure represented by the following general formula (4). preferable.

In the formula (4), R ¹ , R ² and R ³ are each a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the R ¹ , the R ² and the R ³ are the same. May be different.

  In the hard coat film of the present invention, in order to impart antiglare properties, the outer surface structure of the hard coat layer may be an uneven structure. The uneven structure can be formed, for example, by adding fine particles to the hard coat layer forming material.

  In the hard coat film of the present invention, an antireflection layer may be formed on the outer surface of the hard coat layer in order to reduce light reflection at the interface between the hard coat layer and air. If the hard coat film provided with the antireflection layer is applied to, for example, an image display device, the visibility of the image on the display screen can be improved.

  In the hard coat film of the present invention, the antireflection layer preferably contains hollow and spherical silicon oxide fine particles.

  In the hard coat film and the method for producing the same of the present invention, it is preferable that the hard coat layer forming material further contains a leveling agent.

  In the method for producing a hard coat film of the present invention, the drying temperature of the coating film in the step [3] can be appropriately set according to the drying time described later, but is preferably in the range of 80 to 120 ° C. By setting the drying temperature within the above range, it is possible to form a hard coat layer that is superior in adhesion to the transparent plastic film substrate in a shorter drying time without causing shrinkage or breakage of the hard coat film. It becomes possible.

  In the method for producing a hard coat film of the present invention, the drying time of the coating film in the step [3] can be appropriately set according to the drying temperature and the like, but is preferably in the range of 1 to 10 minutes. By making the said drying time into the said range, the hard coat film excellent in the adhesiveness of the said transparent plastic film base material and the said hard-coat layer can be obtained.

A preferable relationship between the drying time and the drying temperature is shown in Table 1 below. However, the relationship between the drying time and the drying temperature shown in Table 1 below is merely an example, and the present invention is not limited to this.
(Table 1)
Drying temperature Drying time
80 to 90 ° C 5 to 10 minutes Over 90 ° C and less than 110 ° C 1 to 5 minutes
110-120 ° C 1-3 minutes

  Next, the present invention will be described in detail. However, the present invention is not limited by the following description.

  The hard coat film of the present invention has a hard coat layer on one side or both sides of a transparent plastic film substrate.

  As described above, the transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin.

The acrylic resin and methacrylic resin are not particularly limited. For example, polyacrylic acid ester, polymethacrylic acid ester, methyl methacrylate-acrylic acid copolymer, methyl methacrylate-methacrylic acid copolymer, methyl methacrylate. -Acrylic acid ester copolymer, Methyl methacrylate-Methacrylic acid ester copolymer, Methyl methacrylate-Acrylic acid ester-Acrylic acid copolymer, Methyl methacrylate-Acrylic acid ester-Methacrylic acid copolymer, Methyl acrylate -Styrene copolymer, methyl methacrylate-styrene copolymer (MS resin), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-acrylic) Acid norbornyl copolymer, methacrylic acid Chill - norbornyl methacrylate copolymer, etc.) and the like. Of these, polyacrylic acid C _1-6 alkyl, polymethacrylic acid C _1-6 alkyl preferably methyl methacrylate-based resins are particularly preferred. The methyl methacrylate resin preferably contains methyl methacrylate in a range of 50 to 100% by weight of the whole, more preferably in a range of 70 to 100% by weight of the whole.

  The glass transition temperature (Tg) of the acrylic resin and the methacrylic resin is preferably 115 ° C. or higher, more preferably 120 ° C. or higher, further preferably 125 ° C. or higher, and particularly preferably 130 ° C. or higher. It is. By setting the Tg to 115 ° C. or higher, a hard coat film with better durability can be obtained. The upper limit of Tg is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like. The Tg is a value calculated by, for example, a DSC method according to JIS K 7192.

  Specific examples of the acrylic resin and the methacrylic resin include, for example, a product name “Acrypet VH” manufactured by Mitsubishi Rayon Co., Ltd., a product name “Acrypet VRL20A” manufactured by the same company, and Japanese Patent Application Laid-Open No. 2004-70296. Examples thereof include acrylic resins and methacrylic resins having a ring structure in the molecule, high-Tg acrylic resins and methacrylic resins obtained by intramolecular crosslinking and intramolecular cyclization reactions.

  As described above, the transparent plastic film substrate preferably includes at least one of an acrylic resin and a methacrylic resin having a lactone ring structure. The resin having the lactone ring structure is excellent in heat resistance, transparency, and mechanical strength.

  Specific examples of the resin having a lactone ring structure include, for example, JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include resins described in JP-A-146084 and JP-A-2006-171464.

  The resin having a lactone ring structure preferably has a lactone ring structure represented by the general formula (4).

In the formula (4), R ¹ , R ² and R ³ are each, for example, a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the R ¹ , the R ² and the R ³ are It may be the same or different. The organic residue may contain an oxygen atom. Specific examples of the organic residue include, for example, a methyl group.

  The content of the lactone ring structure represented by the formula (4) in the entire resin having the lactone ring structure is preferably in the range of 5 to 90% by weight. By making the said content rate into the said range, the hard coat film excellent in heat resistance, solvent resistance, and surface hardness can be obtained, without impairing moldability. The content ratio is more preferably in the range of 10 to 70% by weight, still more preferably in the range of 10 to 60% by weight, and particularly preferably in the range of 10 to 50% by weight. The content ratio of the lactone ring structure represented by the formula (4) in the entire resin having the lactone ring structure is measured by gas chromatography and dynamic TG as described in, for example, JP-A-2006-171464. Can be obtained.

  The glass transition temperature (Tg) of the resin having a lactone ring structure is preferably 115 ° C. or higher. By setting the Tg to 115 ° C. or higher, for example, a hard coat film having excellent durability can be obtained. The Tg is more preferably 125 ° C. or higher, still more preferably 130 ° C. or higher, and particularly preferably 140 ° C. or higher. The upper limit of the Tg is not particularly limited, but is preferably 170 ° C. or less from the viewpoint of moldability and the like.

  The weight average molecular weight (Mw) of the resin having a lactone ring structure is preferably in the range of 1,000 to 2,000,000, more preferably in the range of 5,000 to 1,000,000, and still more preferably in the range of 10,000 to 500,000. Particularly preferably, it is in the range of 50,000 to 500,000. The weight average molecular weight (Mw) can be measured by, for example, a gel permeation chromatograph (GPC) method.

  The higher the total light transmittance of the resin having a lactone ring structure, the better. Specifically, the total light transmittance is preferably 85% or more, more preferably 88% or more, and still more preferably 90% or more. The total light transmittance can be measured according to the method prescribed in ASTM D 1003, for example, using a molded product obtained by injection molding of the resin having the lactone ring structure.

  In this invention, it is preferable that content of the said acrylic resin and methacrylic resin in the said transparent plastic film base material is the range of 50 to 99 weight%. By setting the content in the above range, a hard coat film that is more excellent in heat resistance, transparency, and mechanical strength can be obtained. The content is more preferably in the range of 60 to 98% by weight, and still more preferably in the range of 70 to 97% by weight.

  The method for producing the transparent plastic film substrate is not particularly limited, but a resin composition containing at least one of the acrylic resin and the methacrylic resin is extruded (a melt extrusion method such as a T-die method or an inflation method). A method of stretching a film produced by cast molding (melt casting method or the like) or calender molding is preferred.

  When the film is formed by a dry lamination method, it is necessary to dry and scatter a solvent in an adhesive used during processing, for example, an organic solvent for dry lamination. On the other hand, the extrusion molding does not require a solvent drying step and is excellent in productivity. Specific examples of the extrusion molding include a method in which the resin composition is supplied to an extruder connected to a T die, melted and kneaded, extruded, cooled with water, and taken to form a film. The extruder may be a single screw type or a twin screw type. The resin composition may contain additives such as a plasticizer and an antioxidant as necessary. These additives may be used alone or in combination of two or more.

  The temperature at the time of extrusion molding is not particularly limited, and can be set as appropriate. The temperature is preferably in the range of (Tg + 80) to (Tg + 180) ° C. when the glass transition temperature of the resin composition is Tg (° C.). By setting the temperature within the above range, a film having a uniform thickness can be stably produced. The temperature is more preferably in the range of (Tg + 100) to (Tg + 150) ° C.

  The resin composition is a general compounding agent, for example, an ultraviolet absorber, a stabilizer, a lubricant, a processing aid, a plasticizer, an impact aid, a phase difference reducing agent, a matting agent, an antibacterial agent, and an antifungal agent. Further, it may contain a foam inhibitor and the like. These compounding agents may be used alone or in combination of two or more.

  It is preferable to mix | blend a ultraviolet absorber with the said resin composition. By blending an ultraviolet absorber, weather resistance can be imparted to the hard coat film. The melting point of the ultraviolet absorber is preferably 110 ° C. or higher, more preferably 120 ° C. or higher. In particular, if the melting point of the ultraviolet absorber is 130 ° C. or higher, there is little volatilization during the heat-dissolving processing of the resin composition, and the occurrence of dirt on the roll during film production can be prevented. The ultraviolet absorber is not particularly limited, but a benzotriazole ultraviolet absorber having a molecular weight of 400 or more and a triazine ultraviolet absorber having a molecular weight of 400 or more are particularly preferable. As said ultraviolet absorber, you may use a commercial item, for example. Examples of the commercially available product include trade name “TINUVIN 1577” manufactured by Ciba Specialty Chemicals, Inc., trade name “ADK STAB LA-31” manufactured by Asahi Denka Kogyo Co., Ltd. and the like.

  It is preferable to mix | blend a phase difference reducing agent with the said resin composition. By blending the retardation reducing agent, the in-plane retardation (Re) and the thickness direction retardation (Rth) of the hard coat film can be adjusted. As the phase difference reducing agent, for example, a styrene-containing polymer such as acrylonitrile-styrene copolymer is preferably used. The blending amount of the retardation reducing agent is preferably 30% by weight or less based on the total amount of the acrylic resin and the methacrylic resin. By making the said compounding quantity into the said range, a visible ray is not scattered and transparency of a film is not impaired. The blending amount is more preferably 25% by weight or less, and still more preferably 20% by weight or less, based on the total amount of the acrylic resin and methacrylic resin.

  The stretching may be, for example, stretching by only longitudinal stretching (free end uniaxial stretching) or stretching by only lateral stretching (fixed end uniaxial stretching), but the longitudinal stretching ratio is 1.1. It is preferable that they are sequential biaxial stretching or simultaneous biaxial stretching in which the transverse stretching ratio is in the range of 1.1 to 3.0 times. By making the stretching into the sequential biaxial stretching or the simultaneous biaxial stretching, the strength of the entire transparent plastic film substrate can be increased. Moreover, the transparent plastic film base material which was more excellent in smoothness can be obtained, without producing the fracture | rupture by extending | stretching by making the said longitudinal stretch ratio and the said lateral stretch ratio into the said range. The longitudinal draw ratio is more preferably in the range of 1.2 to 2.5 times, and still more preferably in the range of 1.3 to 2.0 times. The transverse draw ratio is more preferably in the range of 1.2 to 2.5 times, and still more preferably in the range of 1.4 to 2.0 times.

  The stretching temperature is preferably in the range of Tg to (Tg + 30) ° C., where Tg (° C.) is the glass transition temperature of the film to be stretched. By making the said extending | stretching temperature into the said range, it can prevent that the said film fractures | ruptures and fuse | melts, and productivity improves.

  The transparent plastic film substrate has an in-plane retardation (Re) of 3.0 nm or less, a thickness direction retardation (Rth) of 10.0 nm or less, and a tear strength of 2.0 N / mm or more. Is preferred. By setting the Re, the Rth, and the tear strength within the above ranges, both excellent optical characteristics and excellent mechanical strength can be achieved.

  The Re is more preferably 2.0 nm or less, still more preferably 1.5 nm or less, and particularly preferably 1.0 nm or less. The Rth is more preferably 7.0 nm or less, still more preferably 5.0 nm or less, and particularly preferably 3.0 nm or less. The tear strength is more preferably 2.1 N / mm or more, still more preferably 2.2 N / mm or more, still more preferably 2.3 N / mm or more, and particularly preferably 2 N / mm or more. .4 N / mm or more, and most preferably 2.5 N / mm or more.

The moisture permeability of the transparent plastic film substrate is preferably 100 g / m ² · 24 hr or less. By setting the moisture permeability within the above range, it is possible to obtain a hard coat film that is superior in moisture resistance. The moisture permeability is more preferably 60 g / m ² · 24 hr or less. The moisture permeability can be measured, for example, under test conditions of 40 ° C. and a relative humidity of 90% by a method according to JIS Z 0208.

  The haze of the transparent plastic film substrate is preferably as low as possible. The haze is preferably 5% or less. By setting the haze in the above range, a good clear feeling can be visually obtained in the obtained hard coat film. The haze is more preferably 3% or less, still more preferably 1.5% or less, and particularly preferably 1% or less. The haze can be measured, for example, according to a method defined in JIS K 7136 (1981 edition).

  The thickness of the transparent plastic film substrate is preferably 20 μm or more, for example, when the thickness of a hard coat layer described later is 20 μm or more. By setting the thickness in the above range, a transparent plastic film substrate having appropriate strength and rigidity can be obtained without causing breakage. More preferably, the thickness of the transparent plastic film substrate is, for example, in the range of 30 to 40 μm when the thickness of the hard coat layer described later is in the range of 5 to 10 μm. In particular, when the use of the hard coat film of the present invention is a portable device such as a mobile phone, the thickness of the transparent plastic film substrate is, for example, in the range of the thickness of the hard coat layer described later in the range of 5 to 7 μm. In some cases, it is preferably in the range of 20-30 μm.

  The hard coat layer is formed using a hard coat layer forming material containing the following component (A).

Component (A): at least one of polyol acrylate and polyol methacrylate

  Moreover, it is preferable that the said hard-coat layer forming material contains the following (B) component and (C) component further.

(B) component: at least one of urethane acrylate and urethane methacrylate (C) component: a polymer or copolymer formed from at least one of the following (C1) and (C2) below or a mixed polymer of the above polymer and copolymer (C1): hydroxyl group And alkyl acrylate having an alkyl group having at least one acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one of a hydroxyl group and an acryloyl group

  Examples of the component (A) include pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, 1,6-hexanediol acrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol. Tetramethacrylate, dipentaerythritol hexamethacrylate, 1,6-hexanediol methacrylate, and the like. These may be used alone or in combination of two or more. For example, the polyol acrylate is preferably a monomer component made of a polymer of pentaerythritol triacrylate and pentaerythritol tetraacrylate and a mixed component containing pentaerythritol triacrylate and pentaerythritol tetraacrylate.

  The blending ratio of the component (A) is, for example, preferably in the range of 70 to 180% by weight and more preferably in the range of 100 to 150% by weight with respect to the component (B). If the blending ratio of the component (A) is 180% by weight or less with respect to the component (B), curing shrinkage of the hard coat layer to be formed can be effectively prevented. As a result, curling of the hard coat film can be prevented and a decrease in flexibility can be prevented. If the blending ratio of the component (A) is 70% by weight or more of the component (B), the hardness of the hard coat layer to be formed can be further improved, and the scratch resistance can be improved. Become. The scratch resistance can be evaluated by, for example, the method described in Examples described later.

  As described above, the component (A) preferably contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate.

  The blending amount of at least one of the pentaerythritol triacrylate and pentaerythritol tetraacrylate is in the range of 15 to 50 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It is preferable that By making the said compounding quantity into the said range, the hard coat film excellent in the adhesiveness of the said transparent plastic film base material and the said hard-coat layer can be obtained. The blending amount is more preferably in the range of 20 to 40 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C).

  As said urethane acrylate and urethane methacrylate which are said (B) component, what contains acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, a polyol, and diisocyanate as a structural component is used. For example, by using at least one monomer of acrylic acid, methacrylic acid, acrylic acid ester and methacrylic acid ester and a polyol, at least one of hydroxy acrylate having one or more hydroxyl groups and hydroxy methacrylate having one or more hydroxyl groups is produced. Then, at least one of urethane acrylate and urethane methacrylate can be produced by reacting this with diisocyanate. In the said (B) component, urethane acrylate and urethane methacrylate may be used individually by 1 type, and may use 2 or more types together.

  The acrylic ester includes, for example, alkyl acrylate, cycloalkyl acrylate and the like. Examples of the acrylic acrylate include methyl acrylate, ethyl acrylate, isopropyl acrylate, and butyl acrylate. The cycloalkyl acrylate includes, for example, cyclohexyl acrylate. Examples of the methacrylic acid ester include alkyl methacrylate and cycloalkyl methacrylate. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and butyl methacrylate. The cycloalkyl methacrylate includes, for example, cyclohexyl methacrylate.

  The polyol is a compound having at least two hydroxyl groups. Examples of the polyol include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6 -Hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol hydroxypivalate Ester, Tricyclodecane dimethylol, 1,4-cyclohexanediol, Spiroglycol, Tricyclodecane dimethylol, Hydrogenated bisphenol A, Ethylene oxide added bisphenol A, Propylene oxide added bisphenol A, Trimethylo Ethane, trimethylol propane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose, and the like.

  As said diisocyanate, various aromatic, aliphatic, or alicyclic diisocyanates can be used, for example. Examples of the diisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and 3,3-dimethyl-4,4-diphenyl. Diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate and the like, and further hydrogenated products thereof are included.

  The mixing ratio of the component (B) is not particularly limited. By using the component (B), for example, the flexibility of the hard coat layer to be formed and the adhesion to the transparent plastic film substrate can be improved. From these points and the viewpoint of the hardness of the hard coat layer, the blending ratio of the component (B) is, for example, with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It is in the range of 15 to 55 parts by weight, and preferably in the range of 25 to 45 parts by weight.

  In the component (C), the alkyl groups of the (C1) and (C2) are, for example, alkyl groups having 1 to 10 carbon atoms. The alkyl group may be linear or branched. Examples of the component (C) include a polymer, a copolymer or a mixture of the polymer and the copolymer containing the repeating unit of the general formula (2). Examples of the component (C) include 2,3-dihydroxypropyl acrylate, 2,3-diacryloyloxypropyl acrylate, 2-hydroxy-3-acryloyloxypropyl acrylate, 2-acryloyloxy-3-hydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, 2,3-diacryloyloxypropyl methacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, 2-acryloyloxy-3-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-acryloyloxy At least one monomer selected from the group consisting of ethyl acrylate, 2-hydroxyethyl methacrylate and 2-acryloyloxy methacrylate; Formed polymer, a mixture of copolymer or the polymer and the copolymer can be mentioned.

  The blending ratio of the component (C) is not particularly limited. For example, the blending ratio of the component (C) is preferably in the range of 25 to 110% by weight, more preferably in the range of 45 to 85% by weight with respect to the component (B). When the blending ratio of the component (C) is 110% by weight or less with respect to the component (B), the coatability of the hard coat layer forming material becomes excellent. If the blending ratio of the component (C) is 25% by weight or more with respect to the component (B), it is possible to prevent curing shrinkage of the hard coat layer to be formed. As a result, in the hard coat film, for example, within 30 mm Curling can be prevented. The degree of curling is preferably within 20 mm, and more preferably within 10 mm. The curl can be obtained, for example, by placing a hard coat film on a glass plate so that the hard coat layer is on the top and measuring the lifting length (mm) from the glass plate at the four corners.

  As described above, the hard coat layer may contain fine particles in order to make the surface structure an uneven structure. This is because if the surface structure of the hard coat layer is an uneven structure, antiglare properties can be imparted. Examples of the fine particles include inorganic fine particles and organic fine particles. The inorganic fine particles are not particularly limited. Examples of the inorganic fine particles include silicon oxide fine particles, titanium oxide fine particles, aluminum oxide fine particles, zinc oxide fine particles, tin oxide fine particles, calcium carbonate fine particles, barium sulfate fine particles, talc fine particles, kaolin fine particles, and calcium sulfate fine particles. The organic fine particles are not particularly limited. Examples of the organic fine particles include polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, and polyester resin powder. , Polyamide resin powder, polyimide resin powder, polyfluorinated ethylene resin powder and the like. These inorganic fine particles and organic fine particles may be used alone or in combination of two or more.

  The shape of the fine particles is not particularly limited. The shape of the fine particles may be, for example, a bead-like substantially spherical shape. The shape of the fine particles may be an indeterminate shape such as powder. The weight average particle diameter of the fine particles is, for example, in the range of 1 to 30 μm, and preferably in the range of 2 to 20 μm. The fine particles are preferably substantially spherical, more preferably substantially spherical fine particles having an aspect ratio of 1.5 or less. The weight average particle diameter of the fine particles can be measured by, for example, a Coulter counting method. For example, by using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method, the electrolyte solution corresponding to the volume of the particulates when the particulates pass through the pores By measuring the electrical resistance, the number and volume of the fine particles are measured, and the weight average particle diameter is calculated.

  The mixing ratio of the fine particles is not particularly limited. The mixing ratio of the fine particles can be set as appropriate. The mixing ratio of the fine particles is, for example, in the range of 1 to 60 parts by weight, and preferably in the range of 2 to 50 parts by weight with respect to 100 parts by weight of the hard coat layer forming material.

  From the viewpoint of preventing light scattering and interference fringes generated at the interface between the fine particles and the hard coat layer, it is preferable to reduce the refractive index difference between the fine particles and the hard coat layer. The interference fringes are a phenomenon in which reflected light of external light incident on the hard coat film exhibits a rainbow hue. Recently, three-wavelength fluorescent lamps with excellent clarity are frequently used in offices and the like. The interference fringes appear prominently under the three-wavelength fluorescent lamp. Since the refractive index of the hard coat layer is generally in the range of 1.4 to 1.6, fine particles having a refractive index close to this refractive index range are preferred. The difference in refractive index between the fine particles and the hard coat layer is preferably less than 0.05.

  When the difference between the refractive index of the transparent plastic film substrate and the refractive index of the hard coat layer is d, the d is preferably 0.04 or less. If d is 0.04 or less, interference fringes can be suppressed. The d is more preferably 0.02 or less.

  The hard coat film of the present invention is prepared, for example, by preparing a hard coat layer forming material in which the three components are dissolved or dispersed in a solvent, and applying the hard coat layer forming material to at least one surface of the transparent plastic film substrate. It can be manufactured by forming a coating film and curing the coating film to form the hard coat layer.

  Examples of the solvent include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, acetone, methyl ethyl ketone (MEK). ), Diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone (CPN), cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, acetic acid n-pentyl, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1- Butanol, 2-methyl-2-butanol, cyclohexanol, isopropyl alcohol (IPA), isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-heptanone, ethylene Examples include glycol monoethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether. These may be used alone or in combination of two or more. Among the solvents, CPN and MIBK are particularly preferable. These solvents, like the component (A), slightly erode and dissolve the surface of the transparent plastic film base material. By using these solvents, the transparent plastic film base material, the hard coat layer, It becomes possible to further improve the adhesiveness of.

  Various leveling agents can be further added to the hard coat layer forming material. Examples of the leveling agent include a fluorine-based or silicone-based leveling agent, and a silicone-based leveling agent is preferable. Examples of the silicone leveling agent include reactive silicone, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. Among these silicone leveling agents, the reactive silicone is particularly preferable. By adding the reactive silicone, slipperiness is imparted to the surface, and scratch resistance is maintained over a long period of time. When the reactive silicone having a hydroxyl group is used, an antireflection layer (low refractive index layer) containing a siloxane component is formed on the hard coat layer. The adhesion of the layer is improved.

  The blending amount of the leveling agent is, for example, 5 parts by weight or less, and preferably in the range of 0.01 to 5 parts by weight with respect to 100 parts by weight of the whole resin component.

  In the hard coat layer forming material, pigments, fillers, dispersants, plasticizers, UV absorbers, surfactants, antioxidants, thixotropic agents, etc. are added as necessary, as long as the performance is not impaired. May be. The additive may be used alone or in combination of two or more.

  A conventionally well-known photoinitiator can be used for the said hard-coat layer forming material. Examples of the photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoinpropyl ether, benzyl Dimethyl ketal, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, etc. In addition, thioxanthone compounds can be used.

  Examples of the method for coating the hard coat layer forming material on a transparent plastic film substrate include, for example, a phanten coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, and a bar coating method. Etc. can be used.

  The hard coat layer forming material is applied to form a coating film on the transparent plastic film substrate, and the coating film is cured. Prior to the curing, the coating film is preferably dried. The drying may be, for example, natural drying, air drying by blowing air, heat drying, or a combination of these. The drying is preferably heat drying. The drying temperature in the heat drying is as described above. The drying time of the coating film is also as described above.

The means for curing the coating film of the hard coat layer forming material is not particularly limited. The curing means is preferably ionizing radiation curing. Various active energies can be used for the curing means. The active energy is preferably ultraviolet light. As the energy ray source, for example, a high pressure mercury lamp, a halogen lamp, a xenon lamp, a metal halide lamp, a nitrogen laser, an electron beam accelerator, a radioactive element or the like is preferable. The irradiation amount of the energy ray source is preferably in the range of 50 to 5000 mJ / cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm. When the irradiation amount is 50 mJ / cm ² or more, the curing becomes more sufficient, and the hardness of the hard coat layer to be formed becomes more sufficient. If the said irradiation amount is 5000 mJ / cm < ² > or less, the coloring of the said hard-coat layer formed can be prevented and transparency can be improved.

  As described above, the hard coat film of the present invention can be produced by forming the hard coat layer on at least one surface of the transparent plastic film substrate. In addition, you may manufacture the hard coat film of this invention with manufacturing methods other than the above-mentioned method.

  An example of the configuration of the hard coat film of the present invention is shown in the schematic cross-sectional view of FIG. In the figure, the size, ratio, and the like of each component are different from actual ones for easy understanding. As shown in the figure, in this hard coat film 10, a hard coat layer 12 is formed on one side of a transparent plastic film substrate 11. However, the present invention is not limited to this. The hard coat film of the present invention may have a structure in which hard coat layers are formed on both surfaces of a transparent plastic film substrate. Further, the hard coat layer 12 in this example is a single layer. However, the present invention is not limited to this. In the hard coat film of the present invention, the hard coat layer may have a multilayer structure in which two or more layers are laminated.

  The schematic cross-sectional view of FIG. 2 shows another example of the configuration of the hard coat film of the present invention. As shown in the figure, the hard coat film 20 has a configuration in which a hard coat layer 22 is formed on one side of a transparent plastic film substrate 21 and an antireflection layer 23 is formed on the outer surface of the hard coat layer 22. is there. When light strikes an object, it repeats the phenomenon of reflection at the interface, absorption inside, and scattering, and passes through the back of the object. For example, when a hard coat film is mounted on an image display device, one of the factors that lower the image visibility is the reflection of light at the interface between air and the hard coat layer. The antireflection layer reduces the surface reflection. In the hard coat film 20 shown in FIG. 2, the hard coat layer 22 and the antireflection layer 23 are formed on one side of the transparent plastic film substrate 21. However, the present invention is not limited to this. The hard coat film of the present invention may have a structure in which a hard coat layer and an antireflection layer are formed on both surfaces of a transparent plastic film substrate. In the hard coat film 20 shown in FIG. 2, the hard coat layer 22 and the antireflection layer 23 are each a single layer. However, the present invention is not limited to this. In the hard coat film of the present invention, each of the hard coat layer and the antireflection layer may have a multilayer structure in which two or more layers are laminated.

  In the present invention, the antireflection layer is an optical thin film in which thickness and refractive index are strictly controlled, or a laminate of two or more optical thin films. In the antireflection layer, the antireflection function is generated by canceling out the reversed phases of the incident light and the reflected light using the interference effect of light. The wavelength region of visible light that produces the antireflection function is, for example, in the range of 380 to 780 nm, and the wavelength region having particularly high visibility is in the range of 450 to 650 nm. The antireflection layer is preferably designed to minimize the reflectance at 550 nm, which is the central wavelength.

  In designing the antireflection layer based on the light interference effect, as a means for improving the interference effect, for example, there is a method of increasing the refractive index difference between the antireflection layer and the hard coat layer. In general, in a multilayer antireflection layer having a structure in which two to five optical thin layers (thin films whose thickness and refractive index are strictly controlled) are laminated, a plurality of components having different refractive indexes are formed in a predetermined thickness. . Accordingly, the degree of freedom in optical design of the antireflection layer is increased, the antireflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. The optical thin film is required to have high thickness accuracy. For this reason, in general, each layer is formed by a dry method such as vacuum evaporation, sputtering, or CVD.

  The multilayer antireflection layer has a two-layer structure in which a silicon oxide layer having a low refractive index (refractive index: about 1.45) is laminated on a titanium oxide layer having a high refractive index (refractive index: about 1.8). Those are preferred. More preferably, it has a four-layer structure in which a silicon oxide layer is laminated on a titanium oxide layer, another titanium oxide layer is laminated thereon, and another silicon oxide layer is laminated thereon. By forming these two-layer antireflection layers or four-layer antireflection layers, it is possible to uniformly reduce reflection in the visible light wavelength region (for example, a range of 380 to 780 nm).

  An antireflection effect can be exhibited also by forming a single-layer optical thin film (antireflection layer) on the hard coat layer. In general, for forming the single-layer antireflection layer, for example, a wet method such as phanten coating, die coating, spin coating, spray coating, gravure coating, roll coating, or bar coating is employed.

  Examples of the material for forming the single-layer antireflection layer include a resin material such as an ultraviolet curable acrylic resin, a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, tetraethoxysilane, titanium tetraethoxide, and the like. A sol-gel material using a metal alkoxide. The forming material preferably contains a fluorine group for imparting antifouling properties to the surface. The forming material is preferably a forming material having a high content of inorganic components for reasons such as scratch resistance, and more preferably the sol-gel material. The sol-gel material can be used after partial condensation.

  The antireflection layer (low refractive index layer) includes a siloxane oligomer having a number average molecular weight of 500 to 10,000 in terms of ethylene glycol and a fluorine having a polystyrene equivalent number average molecular weight of 5000 or more and having a fluoroalkyl structure and a polysiloxane structure. A material formed from a material containing a compound (a material described in JP-A No. 2004-167827) is preferable because it can achieve both scratch resistance and low reflection.

  The antireflection layer (low refractive index layer) may contain an inorganic sol in order to improve the film strength. The inorganic sol is not particularly limited. The inorganic sol includes, for example, silica, alumina, magnesium fluoride and the like. Among these, silica sol is preferable. The blending ratio of the inorganic sol is, for example, in the range of 10 to 80 parts by weight with respect to 100 parts by weight of the total solid content of the antireflection layer forming material. The weight average particle diameter of the inorganic fine particles in the inorganic sol is preferably in the range of 2 to 50 nm, and more preferably in the range of 5 to 30 nm.

  The material for forming the antireflection layer preferably contains hollow spherical silicon oxide fine particles. The silicon oxide fine particles preferably have a weight average particle diameter of about 5 to 300 nm, and more preferably in the range of 10 to 200 nm. The silicon oxide fine particles have a hollow spherical shape in which a cavity is formed inside an outer shell having pores. The cavity includes at least one of a solvent and a gas when preparing the silicon oxide fine particles. Moreover, it is preferable that a precursor material for forming the cavity of the silicon oxide fine particles remains in the cavity. The thickness of the outer shell is preferably in the range of about 1 to 50 nm and in the range of about 1/50 to 1/5 of the weight average particle size of the silicon oxide fine particles. The outer shell is preferably formed from a plurality of coating layers. In the silicon oxide fine particles, it is preferable that the pores are closed and the cavity is sealed by the outer shell. This is because the porous or voids of the silicon oxide fine particles are maintained in the antireflection layer, and the refractive index of the antireflection layer can be further reduced. As a method for producing such hollow and spherical silicon oxide fine particles, for example, the method for producing silica-based fine particles disclosed in JP-A-2001-233611 is suitably employed.

  The drying and curing temperatures for forming the antireflection layer (low refractive index layer) are not particularly limited. The drying and curing temperature is, for example, in the range of 60 to 150 ° C, and preferably in the range of 70 to 130 ° C. The drying and curing time is, for example, in the range of 1 to 30 minutes, and in view of productivity, the range of 1 to 10 minutes is preferable. Moreover, after the said drying and hardening, the hard-coat film of the high hardness which has an antireflection layer is obtained by performing heat processing further. The temperature of the heat treatment is not particularly limited. The temperature of the said heat processing is the range of 40-130 degreeC, for example, Preferably it is the range of 50-100 degreeC. The heat treatment time is not particularly limited. The said heat processing time is the range of 1 minute-100 hours, for example, and it is more preferable to carry out for 10 hours or more from a viewpoint of an abrasion-resistant improvement. The heat treatment can be performed by a method using a hot plate, an oven, a belt furnace, or the like.

  When the hard coat film including the antireflection layer is attached to an image display device, the antireflection layer is frequently the outermost layer. For this reason, the antireflection layer is susceptible to contamination from the external environment. The antireflection layer is more easily contaminated than a simple transparent plate. For example, the antireflection layer may change the surface reflectance due to adhesion of contaminants such as fingerprints, hand dirt, sweat, and hairdressing materials, or the deposits may appear white and display content may be unclear. In order to prevent adhesion of the contaminants and improve the ease of removing the adhered contaminants, a contamination prevention layer formed from a fluorine group-containing silane compound or a fluorine group-containing organic compound is disposed on the antireflection layer. It is preferable to laminate them.

  In the hard coat film of the present invention, it is preferable to perform a surface treatment on at least one of the transparent plastic film substrate and the hard coat layer. If the surface of the transparent plastic film substrate is surface-treated, the adhesion with the hard coat layer, the polarizer or the polarizing plate is further improved. If the surface of the hard coat layer is surface-treated, the adhesion with the antireflection layer, the polarizer or the polarizing plate is further improved. Examples of the surface treatment include low-pressure plasma treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, and acid or alkali treatment. The alkali treatment can be carried out, for example, by bringing the surface of the transparent plastic film substrate into contact with an alkali solution, washing with water and drying. As the alkaline solution, for example, potassium hydroxide solution and sodium hydroxide solution can be used. The specified concentration (molar concentration) of hydroxide ions in the alkaline solution is preferably in the range of 0.1 to 3.0 N (mol / L), more preferably 0.5 to 2.0 N (mol / L). Range.

  In a hard coat film including a transparent plastic film substrate, and the hard coat layer is formed on one surface of the transparent plastic film substrate, the other surface is treated with a solvent to prevent curling. You may go. The solvent treatment can be carried out by contacting a solvent capable of dissolving the transparent plastic film substrate or a solvent capable of swelling. The solvent treatment gives the transparent plastic film substrate a force to curl the other surface, thereby offsetting the force of the transparent plastic film substrate to curl due to the formation of the hard coat layer. By doing so, the occurrence of curling can be prevented. Similarly, in the hard coat film including the transparent plastic film substrate, and the hard coat layer is formed on one surface of the transparent plastic film substrate, in order to prevent the occurrence of curling, A transparent resin layer may be formed. Examples of the transparent resin layer include a layer mainly composed of a thermoplastic resin, a radiation curable resin, a thermosetting resin, and other reactive resins. Among these, a layer mainly composed of a thermoplastic resin is particularly preferable.

  In the hard coat film of the present invention, the transparent plastic film substrate side can usually be bonded to an optical member used in LCDs and ELDs via an adhesive or an adhesive. In the pasting, various surface treatments as described above may be performed on the surface of the transparent plastic film substrate.

  Examples of the optical member include a polarizer and a polarizing plate. Generally, the polarizing plate has a transparent protective film on one side or both sides of the polarizer. When providing a transparent protective film on both surfaces of a polarizer, the same material may be sufficient as the transparent protective film of front and back, and a different material may be sufficient as it. The polarizing plates are usually disposed on both sides of the liquid crystal cell. Further, the polarizing plates are arranged so that the absorption axes of the two polarizing plates are substantially orthogonal to each other.

  Next, the optical element on which the hard coat film of the present invention is laminated will be described by taking a polarizing plate as an example. A polarizing plate having the function of the present invention can be obtained by laminating the hard coat film of the present invention with a polarizer or a polarizing plate using an adhesive, a pressure sensitive adhesive or the like.

  The polarizer is not particularly limited. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, ethylene / vinyl acetate copolymer partially saponified films, and iodine and dichroic dyes. Examples thereof include a polyene-based oriented film such as a film obtained by adsorbing a chromatic substance and uniaxially stretched, a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product. Among these, a polarizer comprising a polyvinyl alcohol film and a dichroic substance such as iodine is preferable because of its high polarization dichroic ratio. The thickness of the polarizer is not particularly limited. The thickness of the polarizer is, for example, about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared by, for example, dying a polyvinyl alcohol film in an aqueous solution of iodine and stretching it 3 to 7 times the original length. it can. The aqueous solution of iodine may contain boric acid, zinc sulfate, zinc chloride or the like, if necessary. Alternatively, the polyvinyl alcohol film may be immersed in an aqueous solution containing boric acid, zinc sulfate, zinc chloride or the like. If necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol film with water, it is possible to clean the surface of the polyvinyl alcohol film and anti-blocking agent, and by swelling the polyvinyl alcohol film, non-uniformity such as uneven coloring is prevented. There is also an effect. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As the transparent protective film provided on one side or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture shielding property, retardation value stability and the like are preferable. Examples of the material for forming the transparent protective film include the same materials as those for the transparent plastic film substrate.

  Examples of the transparent protective film include polymer films described in JP-A No. 2001-343529 (WO01 / 37007). The polymer film described in the publication includes, for example, (a) a thermoplastic resin having at least one imide group of a substituted imide group and an unsubstituted imide group on the side chain, and (b) a substituted phenyl group and a non-chain on the side chain. Examples thereof include a polymer film formed from a resin composition containing a thermoplastic resin having at least one phenyl group of a substituted phenyl group and a nitrile group. Examples of the polymer film formed from the resin composition include a polymer film formed from a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. can give. The polymer film can be produced by extruding the resin composition into a film. Since the polymer film has a small retardation and a small photoelastic coefficient, when applied to a protective film such as a polarizing plate, problems such as unevenness due to distortion can be solved. The polymer film is excellent in humidification durability because of its low moisture permeability.

  The thickness of the transparent protective film is not particularly limited. The thickness of the transparent protective film is, for example, in the range of 1 to 500 μm from the viewpoint of strength, workability such as handleability, and thin layer properties. When the thickness is within the above range, the polarizer is mechanically protected, and the polarizer does not shrink even when exposed to high temperature and high humidity, and stable optical characteristics can be maintained. The thickness is preferably in the range of 5 to 200 μm, and more preferably in the range of 10 to 150 μm.

  The configuration of the polarizing plate in which the hard coat film of the present invention is laminated is not particularly limited. For example, a transparent protective film, a polarizer and a transparent protective film may be laminated in this order on the hard coat film. And the structure which laminated | stacked the polarizer and the transparent protective film in this order on the hard coat film may be sufficient.

  The hard coat film of the present invention and various optical elements such as a polarizing plate using the hard coat film can be preferably used for various image display devices such as a liquid crystal display device. The liquid crystal display device of the present invention has the same configuration as the conventional liquid crystal display device except that the hard coat film of the present invention is used. The liquid crystal display device of the present invention can be manufactured, for example, by appropriately assembling each component such as a liquid crystal cell, an optical element such as a polarizing plate, and an illumination system (backlight etc.) as necessary, and incorporating a drive circuit. . The liquid crystal cell is not particularly limited. As the liquid crystal cell, various types such as a TN type, an STN type, and a π type can be used.

  In the present invention, the configuration of the liquid crystal display device is not particularly limited, and there are a liquid crystal display device in which the optical element is arranged on one side or both sides of a liquid crystal cell, a liquid crystal display device using a backlight or a reflector in an illumination system, and the like. Can be mentioned. In these liquid crystal display devices, the optical element of the present invention can be arranged on one side or both sides of the liquid crystal cell. When the optical elements are arranged on both sides of the liquid crystal cell, they may be the same or different. Furthermore, various optical members and optical components such as a diffusion plate, an antiglare layer, an antireflection layer, a protective plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight may be disposed in the liquid crystal display device. Good.

  The image display device of the present invention is used for any appropriate application. Applications include, for example, OA equipment such as desktop personal computers, notebook personal computers, and copiers, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, microwave ovens, etc. Household electrical equipment, back monitor, car navigation system monitor, car audio and other in-vehicle equipment, display equipment for commercial store information monitors, security equipment such as monitoring monitors, nursing care monitors, medical monitors, etc. Nursing care / medical equipment.

  Next, examples of the present invention will be described together with comparative examples. However, the present invention is not limited by the following examples and comparative examples. Various characteristics in the following examples and comparative examples were evaluated or measured by the following methods.

(Thickness of hard coat layer)
The total thickness of the hard coat film was measured using a micro gauge type thickness meter manufactured by Mitutoyo Corporation. The thickness of the transparent plastic film substrate was subtracted from the total thickness. Thereby, the thickness of the hard coat layer was calculated.

(Pencil hardness)
The hard coat film was placed on a glass plate with the surface on which the hard coat layer was not formed facing down. Then, the pencil hardness was measured about the said hard-coat layer surface according to the pencil hardness test of JISK5400 (however, load 500g).

(Abrasion resistance)
The scratch resistance of the hard coat film was evaluated by the following test contents.
(1) The sample was cut into a size of at least 25 mm in width and 100 mm in length, and placed on a glass plate.
(2) Steel wool # 0000 is uniformly attached to a smooth cross section of a cylinder having a diameter of 25 mm, and the sample surface is reciprocated 30 times at a speed of about 100 mm per second with a load of 400 g, and then determined by visual evaluation using the following indices. did.
A: There are no scratches.
B: Although there are fine scratches, the visibility is not affected.
C: There is an obvious flaw and the visibility is impaired.

(Adhesion)
The adhesion of the hard coat layer to the transparent plastic film substrate was evaluated by performing a cross-cut peel test described in JIS K 5400. That is, 100 peeling tests were performed, the number of peeling of the hard coat layer from the transparent plastic film substrate was counted, and the number of peeling / 100 was determined by the following index.
A: 0/100
B: 1/100 to 20/100
C: 21/100 or more

(In-plane retardation Re and thickness direction retardation Rth at a wavelength of 590 nm)
The in-plane retardation Re and the thickness direction retardation Rth at a wavelength of 590 nm were measured using a product name “KOBRA21-ADH” manufactured by Oji Scientific Instruments.

[Example 1]
(Preparation of transparent plastic film substrate)
An acrylic resin and a methacrylic resin having a lactone ring structure represented by the general formula (4) (in the general formula (4), R ¹ is —H, R ² and R ³ are —CH ₃ , Polymerization monomer weight ratio: methyl methacrylate / 2- (hydroxymethyl) methyl acrylate = 8/2, lactone cyclization rate: about 100%) and acrylonitrile-styrene (AS) resin (Toyo Styrene Co., Ltd.) A film was obtained by extrusion-molding a mixture with 10 parts by weight of manufactured product name “Toyo AS AS20”. Thereafter, the film was stretched 2.0 times in the longitudinal direction and 2.4 times in the transverse direction to produce a transparent plastic film substrate. The transparent plastic film substrate had a thickness of 30 μm, Re of 0 nm, and Rth of 0 nm.

(Preparation of hard coat layer forming material)
Raw material (Dainippon Ink Chemical Co., Ltd.) containing a resin component containing the following components (A), (B), (C) and a photopolymerization initiator in a solid solvent concentration of 66 wt% The resin raw material was prepared by adding 42 parts by weight of dipentaerythritol hexaacrylate (manufactured by Toagosei Co., Ltd., trade name “Aronix M-402”) to 100 parts by weight of a product name “GRANDIC PC1097”). . In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 15 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It was.

Component (A): dipentaerythritol hexaacrylate (38 parts by weight), pentaerythritol triacrylate (15.5 parts by weight) and pentaerythritol tetraacrylate (40 parts by weight)
Component (B): urethane acrylate (100 parts by weight) composed of isophorone diisocyanate and pentaerythritol acrylate
Component (C): a polymer having a repeating unit represented by the general formula (1), a copolymer, or a mixture of the polymer and the copolymer (30 parts by weight)
Photopolymerization initiator: Trade name “Irgacure 184” (manufactured by Ciba Specialty Chemicals) 3 parts by weight Mixed solvent: butyl acetate: ethyl acetate (weight ratio) = 89: 11

  To 100 parts by weight of the resin raw material, 0.5 parts by weight of a reactive leveling agent (trade name “GRANDIC PC-4100” manufactured by Dainippon Ink & Chemicals, Inc.) is added, so that the solid content concentration becomes 50% by weight. Then, a hard coat layer forming material was prepared by diluting with CPN. The reactive leveling agent is a copolymer copolymerized with dimethylsiloxane: hydroxypropylsiloxane: 6-isocyanatohexylisocyanuric acid: aliphatic polyester (molar ratio) = 6.3: 1.0: 2.2: 1.0. It is a polymer.

(Preparation of hard coat film)
The hard coat layer forming material was applied onto the transparent plastic film substrate using a bar coater to form a coating film. After the coating, the coating film was dried by heating at 100 ° C. for 1 minute. The dried coating film was cured by irradiating with an ultraviolet ray having an integrated light quantity of 300 mJ / cm ² with a metal halide lamp to form a hard coat layer having a thickness of 10 μm. In this manner, a hard coat film according to this example was produced.

[Example 2]
As a resin raw material, 100 parts by weight of the raw material used in Example 1 (manufactured by Dainippon Ink and Chemicals, trade name “GRANDIC PC1097”), dipentaerythritol hexaacrylate (manufactured by Toagosei Co., Ltd., trade name “ A hard coat film according to this example was produced in the same manner as in Example 1 except that 15 parts by weight of Aronix M-402 ") was used. In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 20 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It was.

[Example 3]
This example is the same as in Example 1 except that the raw material used in Example 1 (trade name “GRANDIC PC1097” manufactured by Dainippon Ink and Chemicals, Inc.) was used as the resin raw material. The hard coat film which concerns on was produced. In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 25 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It was.

[Example 4]
As a resin raw material, 100 parts by weight of the raw material used in Example 1 (trade name “GRANDIC PC1097” manufactured by Dainippon Ink & Chemicals, Inc.) and pentaerythritol triacrylate and pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd.) ), A hard coat film according to this example was produced in the same manner as in Example 1, except that 5 parts by weight of a trade name “MK Ester A-TMM-3L”) was used. . In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 30 parts by weight with respect to 100 parts by weight of the total of the component (A), the component (B) and the component (C). It was.

[Example 5]
As a resin raw material, 100 parts by weight of the raw material used in Example 1 (trade name “GRANDIC PC1097” manufactured by Dainippon Ink & Chemicals, Inc.) and pentaerythritol triacrylate and pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd.) ), A hard coat film according to this example was produced in the same manner as in Example 1 except that 17 parts by weight of a trade name “MK Ester A-TMM-3L”) was used. . In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 40 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It was.

[Example 6]
As a resin raw material, 100 parts by weight of the raw material used in Example 1 (trade name “GRANDIC PC1097” manufactured by Dainippon Ink & Chemicals, Inc.) and pentaerythritol triacrylate and pentaerythritol tetraacrylate (Shin Nakamura Chemical Co., Ltd.) ), A hard coat film according to this example was produced in the same manner as in Example 1 except that 33 parts by weight of a trade name “MK Ester A-TMM-3L”) was used. . In this example, the total amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate was 50 parts by weight with respect to a total of 100 parts by weight of the component (A), the component (B) and the component (C). It was.

[Example 7]
The hard coat film which concerns on a present Example was produced by the method similar to Example 5 except having changed the drying temperature of the coating film at the time of the said hard coat film preparation into 110 degreeC.

[Example 8]
The hard coat film which concerns on a present Example was produced by the method similar to Example 5 except having changed the drying temperature of the coating film at the time of the said hard coat film preparation into 120 degreeC.

[Example 9]
In this example, the same method as in Example 3 was used except that the drying temperature of the coating film was changed to 90 ° C. and the drying time of the coating film was changed to 5 minutes. The hard coat film which concerns on was produced.

[Example 10]
This example is the same as Example 3 except that the drying temperature of the coating film during the production of the hard coat film was changed to 80 ° C. and the drying time of the coating film was changed to 5 minutes. The hard coat film which concerns on was produced.

  Various characteristics were measured or evaluated for each hard coat film of the example obtained in this manner. The results are shown in Table 2 below. In Table 2, the PETA blending amount means the total blending amount of pentaerythritol triacrylate and pentaerythritol tetraacrylate with respect to 100 parts by weight of the total of component (A), component (B) and component (C).

  As shown in Table 2, the hard coat films of Examples 2 to 5 and 7 to 10 were excellent in adhesion between the transparent plastic film substrate and the hard coat layer. The hard coat films of Examples 1 and 6 were slightly inferior in adhesion between the transparent plastic film substrate and the hard coat layer as compared with the hard coat films of Examples 2 to 5 and 7 to 10. It was a level with no problem.

  The hard coat film of the present invention has excellent moisture resistance, heat resistance, gas barrier properties and durability, and also has excellent adhesion between the transparent plastic film substrate and the hard coat layer. Therefore, the hard coat film of the present invention can be suitably used for various image display devices such as optical elements such as polarizing plates, CRTs, LCDs, PDPs, and ELDs, for example. It is.

10, 20 Hard coat film 11, 21 Transparent plastic substrate 12, 22 Hard coat layer 23 Antireflection layer

Claims (23)

A hard coat film having a hard coat layer on at least one surface of a transparent plastic film substrate,
The transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin;
A hard coat film, wherein the hard coat layer is formed using a hard coat layer forming material containing the following component (A).
Component (A): at least one of polyol acrylate and polyol methacrylate The hard coat film according to claim 1, wherein the component (A) contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. The hard coat film according to claim 1 or 2, wherein the hard coat layer forming material further comprises the following components (B) and (C).
(B) component: at least one of urethane acrylate and urethane methacrylate (C) component: a polymer or copolymer formed from at least one of the following (C1) and (C2) below or a mixed polymer of the above polymer and copolymer (C1): hydroxyl group And alkyl acrylate having an alkyl group having at least one acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one of a hydroxyl group and an acryloyl group At least one of the pentaerythritol triacrylate and pentaerythritol tetraacrylate is blended in the range of 15 to 50 parts by weight with respect to 100 parts by weight of the component (A), the component (B) and the component (C). The hard coat film according to claim 3. The hard coat film according to claim 3 or 4, wherein the component (C) includes a polymer, a copolymer, or a mixture of the polymer and the copolymer including a repeating unit represented by the following general formula (1).

In the formula (1), R ¹ is —H or —CH ₃ , R ² is —CH ₂ CH ₂ OX or a group represented by the following general formula (2), and the X is — H or an acryloyl group represented by the following general formula (3).

In the formula (2), two Xs are —H or an acryloyl group represented by the following general formula (3), and each X may be the same or different.

The hard coat film according to any one of claims 1 to 5, wherein the transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin having a lactone ring structure. The hard coat according to any one of claims 1 to 6, wherein the transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin having a lactone ring structure represented by the following general formula (4). the film.

In the formula (4), R ¹ , R ² and R ³ are each a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the R ¹ , the R ² and the R ³ are the same. May be different. The hard coat film according to any one of claims 1 to 7, wherein an outer surface structure of the hard coat layer is an uneven structure. The hard coat film according to any one of claims 1 to 8, wherein an antireflection layer is laminated on an outer surface of the hard coat layer. The hard coat film according to claim 9, wherein the antireflection layer contains hollow spherical silicon oxide fine particles. The hard coat film according to any one of claims 1 to 10, wherein the hard coat layer forming material further contains a leveling agent. A method for producing a hard coat film having a hard coat layer on at least one surface of a transparent plastic film substrate, comprising the following steps [1] to [4]: Method.
[1] Step of preparing a transparent plastic film substrate containing at least one of an acrylic resin and a methacrylic resin [2] A hard coat containing the following component (A) on at least one surface of the transparent plastic film substrate Step [3] for forming a coating film by applying a layer forming material [4] Step for drying the coating film [4] Step for curing the coating film after the step [3] and forming a hard coat layer Component (A): at least one of polyol acrylate and polyol methacrylate The method for producing a hard coat film according to claim 12, wherein the component (A) contains at least one of pentaerythritol triacrylate and pentaerythritol tetraacrylate. The method for producing a hard coat film according to claim 12 or 13, wherein the hard coat layer forming material further comprises the following components (B) and (C).
(B) component: at least one of urethane acrylate and urethane methacrylate (C) component: a polymer or copolymer formed from at least one of the following (C1) and (C2) below or a mixed polymer of the above polymer and copolymer (C1): hydroxyl group And alkyl acrylate having an alkyl group having at least one acryloyl group (C2): alkyl methacrylate having an alkyl group having at least one of a hydroxyl group and an acryloyl group At least one of the pentaerythritol triacrylate and pentaerythritol tetraacrylate is blended in the range of 15 to 50 parts by weight with respect to 100 parts by weight of the component (A), the component (B) and the component (C). The method for producing a hard coat film according to claim 14. The method for producing a hard coat film according to claim 14 or 15, wherein the component (C) comprises a polymer, a copolymer, or a mixture of the polymer and the copolymer containing a repeating unit of the following general formula (1).

In the formula (1), R ¹ is —H or —CH ₃ , R ² is —CH ₂ CH ₂ OX or a group represented by the following general formula (2), and the X is — H or an acryloyl group represented by the following general formula (3).

In the formula (2), two Xs are —H or an acryloyl group represented by the following general formula (3), and each X may be the same or different.

The method for producing a hard coat film according to any one of claims 12 to 16, wherein the transparent plastic film substrate contains at least one of an acrylic resin and a methacrylic resin having a lactone ring structure. The hard coat according to any one of claims 12 to 17, wherein the transparent plastic film substrate includes at least one of an acrylic resin and a methacrylic resin having a lactone ring structure represented by the following general formula (4). A method for producing a film.

In the formula (4), R ¹ , R ² and R ³ are each a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the R ¹ , the R ² and the R ³ are the same. May be different. The method for producing a hard coat film according to any one of claims 12 to 18, wherein a drying temperature in drying the coating film in the step [3] is in a range of 80 to 120 ° C. The method for producing a hard coat film according to claim 19, wherein the drying time in drying of the coating film in the step [3] is in the range of 1 to 10 minutes. The hard coat film manufactured by the manufacturing method as described in any one of Claims 12-20. An optical element in which a hard coat film is laminated on at least one surface of the optical member, wherein the hard coat film is the hard coat film according to any one of claims 1 to 11 and 21. A featured optical element. An image display device comprising a hard coat film or an optical element, wherein the hard coat film is the hard coat film according to any one of claims 1 to 11 and 21, and the optical element is claim 22. An image display device comprising the optical element described above.

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