JP2014235235A - Fingerprint-proof film for display and display including the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fingerprint-proof film for a display, which has good fingerprint-proof property and image visibility without forming a rugged pattern on a surface of a coating layer, and which prevents color irregularity.SOLUTION: The fingerprint-proof film includes the following coating film on a transparent substrate film. The coating film comprises (A) a polyalkylene glycol acrylate expressed by chemical formula (1) shown below, (B) an acrylate compound having three or more functional groups, and (C) a photopolymerization initiator, in which a ratio of parts by mass of (A) to (B) is 20:80 to 50:50 (where the total parts by mass of (A) and (B) is 100), and (C) is included by 1 to 10 parts by mass in the total 100 parts by mass of (A) and (B). An oriented polyester film is used for the transparent substrate film, which has a difference (nx-ny) of 0.07 to 0.20 between a refractive index (nx) in a slow axis direction and a refractive index (ny) in an advance axis direction.

Description

  The present invention relates to a fingerprint-resistant film for a display excellent in fingerprint resistance, and a display including the same.

  A small device such as a mobile phone or a digital camera having a display is likely to lose visibility of an image because a fingerprint is attached to the display surface when the device is operated or carried. Recently, the display itself has become a touch panel, and fingerprints tend to adhere due to finger input. In order to solve these problems, a countermeasure for making the fingerprint attached to the display surface inconspicuous is proposed, for example, in Patent Document 1 below.

  In patent document 1, the glare-proof layer (coating layer) which has an unevenness | corrugation is formed in the surface of a transparent base material. The antiglare layer is compatible with a biological lipid component comprising an active energy ray-curable resin such as an ester compound of polyhydric alcohol and (meth) acrylic acid, and an acrylate compound different from the active energy ray-curable resin. In addition to the polymer having the above, it comprises translucent fine particles. In such an antiglare layer, the antiglare property is expressed by forming irregularities on the surface of the antiglare layer by the light-transmitting fine particles. On the other hand, the fingerprint that adheres to the film surface wets and spreads quickly due to the polymer that is compatible with the bio-derived oil and fat component, and is quickly guided to the concave portion of the surface. Thereby, the fingerprint adhering to the film surface becomes difficult to stand out.

  Patent Document 2 discloses a coating layer composed of polyalkylene glycol diacrylate, a tri- or higher functional acrylate compound, and a photopolymerization initiator, a polyester film represented by polyethylene terephthalate (PET), triacetate cellulose ( A display film provided on one surface of a TAC-based film has been proposed. In the coating layer, (A) a specific polyalkylene glycol diacrylate is blended in a predetermined ratio with respect to (B) a tri- or higher functional acrylate compound as an acrylate compound that is compatible with biological lipids such as fingerprints. ing. Thereby, in the film for a display which provides the coating layer with the smooth surface, favorable fingerprint resistance can be expressed.

JP 2009-25734 A Japanese Patent Application Laid-Open No. 2011-232441

  In the film for display of patent document 1, antiglare property is ensured by mix | blending translucent microparticles | fine-particles with an anti-glare layer and forming an unevenness | corrugation on the surface. However, when such a display film is placed on a high-definition display such as a mobile phone or a digital camera, the image light is scattered by the lens effect of the surface unevenness of the antiglare layer, and the scintillation phenomenon occurs. As a result, there is a problem that image visibility of characters, lines and the like is impaired. In addition, various acrylate compounds are exemplified as polymers that are compatible with biological lipid components, but these acrylate compounds guarantee a certain fingerprint resistance in the antiglare layer having irregularities on the surface. It is. However, in a film having a smooth surface, all of these acrylate compounds cannot guarantee sufficient fingerprint resistance.

  The display film described in Patent Document 2 is excellent in fingerprint resistance in a film having a smooth surface, but a transparent polyester film such as a general polyester film represented by polyethylene terephthalate (PET) or triacetate cellulose (TAC). ) Film is used. When a display film using a general polyester film is arranged on a polarizing element, unevenness of different colors (hereinafter also referred to as “NIJIMURA”) occurs in the liquid crystal display device, particularly when the display screen is observed obliquely. It has been found that there is a problem that the display quality of the liquid crystal display device is impaired. In addition, a display film using a triacetate cellulose (TAC) film does not cause the problem of Nizimura, but has a problem that it is difficult to store and use for a long time in a high temperature and high humidity environment due to poor heat and heat resistance. It has been found.

  Therefore, the present invention has been made to solve such problems, and has good fingerprint resistance and image visibility without forming irregularities on the surface of the coating layer, and on the polarizing element. An object of the present invention is to provide a fingerprint-resistant film for display and the like that does not cause wiggle even if it is arranged and the display screen is observed obliquely.

[２]（Ｂ）の３官能以上のアクリレート化合物が、３官能以上のアルコールと（メタ）アクリル酸とのエステル化合物である[１]に記載のディスプレイ用耐指紋性フィルム。
[３][１]又は[２]に記載のディスプレイ用耐指紋性フィルムが表示画面上に配置されているディスプレイ。 In order to solve the above problems, the present invention employs the following means.
[1] (A) A polyalkylene glycol diacrylate represented by the following chemical formula (1), (B) a trifunctional or higher functional acrylate compound, and (C) a photopolymerization initiator,
(A) mass part: (B) mass part is 20:80 to 50:50 (provided that (A) mass part + (B) mass part = 100),
A coating layer containing 1 to 10 parts by mass of (C) is provided on a transparent substrate film with respect to 100 parts by mass of (A) and (B) in total,
The transparent base film has a refractive index (nx) in the direction having the highest refractive index (slow axis direction) and a refractive index in the direction orthogonal to the slow axis direction (fast axis direction). A fingerprint-resistant film for display, which is an oriented polyester film having a difference (nx−y) from (ny) of 0.07 to 0.20.
Display film on the surface.

[2] The fingerprint-resistant film for display according to [1], wherein the trifunctional or higher acrylate compound of (B) is an ester compound of trifunctional or higher alcohol and (meth) acrylic acid.
[3] A display in which the anti-fingerprint film for display according to [1] or [2] is disposed on a display screen.

  In the present invention, “XX to XX” indicating a numerical range means “XX or more and XX or less” unless otherwise specified. “(Meth) acrylic acid” means both acrylic acid and methacrylic acid. The same applies to “(meth) acryloyl group” and “(meth) acrylate” described later.

  In the anti-fingerprint film for display of the present invention, the coating layer does not contain fine particles. Therefore, the surface of the coating layer is smooth. The term “smooth” as used herein means that there are no positive irregularities due to fine particles or the like, and does not deny the ultra-nano-sized irregularities that are inevitably generated in the film formation process. Thereby, the deterioration of image visibility, such as a character and a line by the surface unevenness | corrugation which is a problem by patent document 1, can be avoided.

  In addition, (A) a specific polyalkylene glycol diacrylate is used as a acrylate compound that is compatible with biologically derived lipids such as fingerprints, and (B) a trifunctional or higher functional acrylate compound at a predetermined ratio. It is blended. As described in Patent Document 1, many acrylate compounds that are compatible with biological lipids exist, and various acrylate compounds exist as diacrylate compounds. However, polyalkylene glycol diacrylate is the only acrylate compound that can make the attached fingerprints less noticeable in a coating having a smooth surface. Thereby, in the anti-fingerprint film for display which provides a coating layer with a smooth surface, good anti-fingerprint property can be expressed without forming irregularities on the surface.

  In addition, since a predetermined oriented polyester film is used for the transparent substrate film, when the anti-fingerprint film for display according to the present invention is arranged on the polarizing element, even if the display screen is observed obliquely, It does not occur. Moreover, since it is excellent in heat-and-moisture resistance compared to a TAC film, the quality is not deteriorated even in a high-temperature and high-humidity environment, and it is suitable for long-term storage and use.

  In the film of the present invention, a coating layer is formed on a transparent substrate film. The coating layer is a cured coating of a monomer composition comprising (A) a polyalkylene glycol diacrylate represented by the chemical formula (1), (B) a trifunctional or higher functional acrylate compound, and (C) a photopolymerization initiator. is there.

<Transparent substrate film>
An oriented polyester film (also referred to as a high birefringence film) made of polyester such as polyethylene terephthalate (PET) is used for the transparent substrate film used for the fingerprint-resistant film for display of the present invention. In particular, the difference (nx−ny: Δn) between the refractive index (nx) in the slow axis direction and the refractive index (ny) in the fast axis direction is 0.07 to 0.20, preferably 0.10 to 0 .15 is used. If this refractive index difference (Δn) is less than 0.07, a sufficient effect of suppressing azimuth cannot be obtained, and a film thickness necessary for obtaining a retardation value described later is increased. On the other hand, when the refractive index difference (Δn) exceeds 0.20, the film is easily torn and torn, and the practicality as an industrial material is significantly reduced. (Nx) is preferably 1.67 to 1.78, more preferably 1.69 to 1.73. (Ny) is preferably 1.55 to 1.65, more preferably 1.57 to 1.62. (Nx), (ny), and ((DELTA) n) satisfy | fill said relationship, and can obtain the suitable inhibitory effect of Nijimura.

  Moreover, as for the retardation of an oriented polyester film, 3000-30000 nm is preferable. When the retardation is less than 3000 nm, when the anti-fingerprint film is arranged on the polarizing element, it exhibits a strong interference color (Nizimura) when observed from an oblique direction, and the envelope shape is different from the emission spectrum of the light source and has good visibility. May not be secured. On the other hand, even if the retardation exceeds 30000 nm, not only a further improvement effect of visibility can be obtained, but also the thickness of the film becomes considerably thick and the handleability is lowered. The lower limit value of the retardation is more preferably 5000 nm or more, and further preferably 10,000 nm or more.

Retardation refers to the refractive index (nx) in the direction having the highest refractive index (slow axis direction) in the plane of the polyester film, and the refractive index in the direction orthogonal to the slow axis direction (fast axis direction) ( ny) and the thickness (d) of the polyester film are represented by the following formula.
Retardation (Re) = (nx−ny) × d
Retardation can also be measured (measurement angle 0 °, measurement wavelength 548.2 nm) by KOBRA-WR manufactured by Oji Scientific Instruments, for example.

  The oriented polyester film can be crystal-oriented by stretching an unstretched polyester film in one or both of the longitudinal and lateral directions. The retardation control method can be appropriately set according to the draw ratio, the draw temperature, and the thickness of the polyester film to be produced. Specifically, the higher the draw ratio, the lower the draw temperature, and the thicker the film, the easier it is to obtain high retardation, and the lower the draw ratio, the higher the draw temperature and the thinner the film thickness. The lower the retardation, the easier it is to obtain.

  The thickness of the oriented polyester film is preferably 25 to 400 μm, more preferably 50 to 200 μm. When the thickness of the oriented polyester film is thinner than 25 μm or thicker than 400 μm, the handleability during the production and use of the anti-fingerprint film is lowered, and it is difficult to set the retardation within the above range. The oriented polyester film may contain various additives as long as the retardation is in the above range. Examples of such additives include ultraviolet absorbers, antistatic agents, stabilizers, plasticizers, lubricants, flame retardants, and the like.

(A) Polyalkylene glycol diacrylate The polyalkylene glycol diacrylate that can be used in the anti-fingerprint film of the present invention is a compound represented by the following chemical formula (1). The compound represented by the chemical formula (1) is compatible with living body-derived lipid components including sebum, and can make fingerprints attached to the film surface inconspicuous. There are various types of polyalkylene glycol diacrylate compounds, but the only polyalkylene glycol diacrylates that make the attached fingerprints less noticeable on the smooth coating surface are polyalkylene glycol diacrylates represented by the following chemical formula (1).

(B) Trifunctional or higher acrylate compound The trifunctional or higher acrylate compound that can be used in the display film of the present invention is a compound having three or more (meth) acryloyl groups in one molecule, and is a trifunctional or higher alcohol. And an ester compound of (meth) acrylic acid and urethane-modified acrylate.

  Examples of the tri- or higher functional alcohol include pentaerythritol, dipentaerythritol, and ditrimethylolpropane. In the present invention, (meth) acrylic acid means acrylic acid or methacrylic acid. Examples of the ester compound of trifunctional or higher alcohol and (meth) acrylic acid include ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, and pentaerythritol triacrylate.

  The urethane-modified acrylate is obtained by a urethanization reaction between an organic isocyanate having a plurality of isocyanate groups in one molecule and a (meth) acrylic acid ester having a hydroxyl group. Examples of the organic isocyanate having a plurality of isocyanate groups in one molecule include hexamethylene diisocyanate, isophorone diisocyanate, and tolylene diisocyanate. Examples of the (meth) acrylic acid ester having a hydroxyl group include pentaerythritol tri (meth) acrylate and 2-hydroxy-3-acryloyloxypropyl methacrylate.

Examples of the urethane-modified acrylate include an adduct of pentaerythritol triacrylate and hexamethylene diisocyanate represented by chemical formula (2), an adduct of pentaerythritol triacrylate and isophorone diisocyanate represented by chemical formula (3), and chemical formula (4). There is an adduct of 2-hydroxy-3-acryloyloxypropyl methacrylate and tolylene diisocyanate. Commercially available products include purple light UV7600MI85 (manufactured by Nippon Synthetic Chemical), purple light UV6300B, (manufactured by Nippon Synthetic Chemical).

  The trifunctional or higher functional acrylate compound is a component for imparting physical properties such as pencil hardness and scratch resistance to the cured coating film (coating layer) in the display fingerprint-resistant film of the present invention. In general, ester compounds of these tri- or higher functional alcohols and (meth) acrylic acid are used as substances that increase the cross-linking density of a cured coating film and impart physical properties to the cured coating film. The trifunctional or higher functional acrylate compound is preferably an ester compound of trifunctional or higher functional alcohol and (meth) acrylic acid in terms of scratch resistance.

  As described above, in the fingerprint-resistant film for display of the present invention, (A) the polyalkylene glycol diacrylate represented by the chemical formula (1) has fingerprint resistance, and (B) a trifunctional or higher functional acrylate compound has physical properties. (Pencil hardness, scratch resistance, etc.) In order to achieve both fingerprint resistance and physical properties, the mass part of (A): mass part of (B) is at least 20:80 to 50:50 (however, mass part of (A) + mass of (B) Part = 100). Preferably, mass parts of (A): mass parts of (B) = 30: 70 to 40:60. When the mass part of (A) is smaller than 20 with respect to the mass part of (B), the fingerprint resistance is deteriorated, and when more than 50, the physical property is deteriorated. In addition, although the coating film of only (A) polyalkylene glycol diacrylate is satisfied with fingerprint resistance, physical properties (pencil hardness, scratch resistance) are insufficient.

(C) Photopolymerization initiator (A) Polyalkylene glycol diacrylate represented by chemical formula (1) and (B) trifunctional or higher functional acrylate compound are active energy such as ultraviolet rays and light in the presence of a photopolymerization initiator. It is an active energy ray curable resin (ionizing radiation curable resin) that is polymerized and cured by irradiation with a line. The photopolymerization initiator is not particularly limited as long as it initiates polymerization upon irradiation with active energy rays, and a known compound can be used, but an alkylphenone photopolymerization initiator is preferable. Examples of the alkylphenone photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, And 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one. As an active energy ray source used for curing the active energy ray-curable resin composition, for example, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, or the like can be used.

  In the anti-fingerprint film for display of the present invention, (C) the photopolymerization initiator is blended in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of (A) + 100 parts by mass of (B). (A) A monomer composition comprising a polyalkylene glycol diacrylate represented by the chemical formula (1) and (B) a trifunctional or higher functional acrylate compound can be cured. When the mass part of (C) is less than 1 with respect to 100 parts by mass of (A) + mass part of (B) = 100, the physical properties deteriorate due to insufficient curing, and when more than 10, the fingerprint resistance is high. Getting worse.

  The film thickness of the coating layer may be about 1 to 15 μm. When it is thinner than 1 μm, physical properties are insufficient, and when it is thicker than 15 μm, the curl of the film tends to be strong.

  The fingerprint-resistant film of the present invention is stuck on the display screen of various electronic devices having a display. Specifically, liquid crystal displays, plasma displays, organic EL (electroluminescence) displays, inorganic EL displays, FEDs (field emissions) in electronic imaging devices and touch panels such as mobile phones, digital cameras, televisions, video cameras, word processors, and personal computers. Applicable to various displays such as display. In particular, the present invention is preferably applied to a high-definition display such as a mobile phone or a digital camera whose display itself is a touch panel because the effects of the present invention can be maximized.

  The method for forming a film on the transparent substrate film may be a conventionally known method and is not particularly limited. Examples of the method for forming the film include a lie coating method and a wet coating method, and the wet coating method is preferable from the viewpoint of productivity or cost. The wet coating method may be a known one, and examples thereof include a roll coating method, a spin coating method, and a dip coating method. Further, in order to improve the adhesion between the film substrate and the cured coating (coating layer), the surface of the transparent substrate can be subjected to some pretreatment such as corona discharge in advance as necessary.

  In applying the monomer composition comprising the above (A), (B) and (C) on the transparent substrate, a diluting solvent can be used to adjust the concentration of the coating solution (coating agent). The diluent solvent is not particularly limited, and examples thereof include methyl isobutyl ketone, methyl ethyl ketone, isopropyl alcohol, xylene, ethyl acetate, and butyl acetate.

  Haze, fingerprint visibility (reflection, transmission), image visibility, scratching properties, pencil hardness, refractive index, film thickness, retardation, and Nizimura were measured by the methods shown below.

(1) Haze Haze was measured with a haze meter (“NDH2000”, manufactured by Nippon Denshoku Industries Co., Ltd.).
(2) Fingerprint visibility (reflection)
A display film is laminated on glass, and a black film is laminated on the back side of the glass as an evaluation sample. A fingerprint is deposited on the display film. Fingerprints should be observed indoors without sunlight. While the light is reflected on the sample for evaluation (does not reflect the light of the fluorescent lamp), the visibility of the fingerprint is observed. Sensory evaluation by visual observation was performed in the following four stages for fingerprint visibility.
A: The fingerprint is not visible at all, O: The fingerprint is almost invisible, Δ: The fingerprint is slightly visible, X: The fingerprint is clearly visible.
(3) Fingerprint visibility (transmission)
A display film laminated to glass is used as an evaluation sample, and a fingerprint is attached on the display film. Fingerprints should be observed indoors without sunlight. The sample for evaluation was directed to the light of the fluorescent lamp, and the fingerprint visibility was observed in a state slightly shifted from the light of the fluorescent lamp. The visibility was subjected to visual sensory evaluation in the following four stages.
A: The fingerprint is not visible at all, O: The fingerprint is almost invisible, Δ: The fingerprint is slightly visible, X: The fingerprint is clearly visible.
(4) Image Visibility A display film was mounted on the display screen of a high-definition display, and visual evaluation was performed on the visibility of the display image in the following three stages.
○: Visible and good visibility is obtained, Δ: Slightly visible, ×: Poor visibility.
(5) Scratch resistance Using # 0000 steel wool, the surface of the coating film after 250 g load × 10 reciprocation was visually observed, and sensory evaluation was performed on the scratch resistance in the following five stages.
A: No scratch, A ': 1-10 scratches, B: 11-20 scratches, C: 21-30 scratches, D: 31 or more scratches (6) Pencil hardness Pencil made by Yasuda Seiki Seisakusho Using a scratch hardness tester, the pencil hardness was measured in accordance with JIS K 5600.
(7) Refractive index Using two polarizing plates, the orientation axis direction (major axis direction) of the highly birefringent film is obtained, and the refractive indices (nx, ny) of two axes orthogonal to the orientation axis direction are obtained. And an Abbe refractometer (NAR-4T manufactured by Atago Co., Ltd.).
(8) Film thickness Thickness d (nm) measured 10 points | pieces using the electric micrometer (made by Anritsu), converted the unit into nm, and calculated | required the average value.
(9) Retardation Retardation is the refraction index (nx) in the direction having the highest refractive index (slow axis direction) in the plane of the high birefringence film, and the direction (fast axis direction) perpendicular to the slow axis direction. The calculation was performed according to the following formula based on the refractive index (ny) and the thickness (d) of the highly birefringent film.
Retardation (Re) = (nx−ny) × d
(10) Nijimura The anti-fingerprint film produced in the examples and comparative examples was placed on the polarizing element on the observer side of a liquid crystal monitor (FLATRONIPS 226V (manufactured by LG Electronics Japan)). Note that the angle between the slow axis of the oriented polyester film and the absorption axis of the polarizing element on the observer side of the liquid crystal monitor was set to 0 °. In the dark and bright places (illuminance around the LCD monitor 400 lux), the display image is observed visually and through polarized sunglasses from the front and oblique directions (about 50 degrees), and the presence or absence of nidimra is evaluated according to the following criteria. did. Observation through polarized sunglasses is a much stricter evaluation method than visual observation. The observation is performed by 10 people, and the largest number of evaluations are the observation results.
A: Nijimura is not observed through polarized sunglasses.
◯: Nijimura is observed through polarized sunglasses, but it is thin and Nizamura is not visually observed.
Δ: Nizimura is observed through polarized sunglasses, and Nizimura is observed very thin by visual observation.
X: Nizimura is strongly observed through polarized sunglasses, and Nizimura is also observed visually.

(Preparation of oriented polyester film (PET-N))
Molten polyethylene terephthalate was melted at 290 ° C., extruded through a film-forming die, into a sheet form, closely contacted on a water-cooled cooled quenching drum, and cooled to produce an unstretched film. This unstretched film was preheated at 120 ° C. for 1 minute with a biaxial stretching test apparatus (manufactured by Toyo Seiki Co., Ltd.), then stretched at 120 ° C. at a stretch ratio of 4.5 times, and then a primer layer on both surfaces thereof The composition 1 was applied uniformly with a roll coater. Next, this coated film was subsequently dried at 95 ° C., and stretched at a stretching ratio of 1.5 times in the direction of 90 ° with respect to the stretching direction, retardation = 10000 nm, film thickness = 100 μm, nx = 1.70, An oriented polyester base material having ny = 1.60 and Δn = 0.10 was obtained. The primer layer had a refractive index of 1.59 and a film thickness of 80 nm.

Example 1
Polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 9) 30 parts by mass Dipentaerythritol hexaacrylate (DPHA) 70 parts by mass
1-hydroxycyclohexyl phenyl ketone 7.5 parts by mass Methyl isobutyl ketone (MIBK) 100 parts by mass

The said raw material was mixed and it was set as the coating agent. This coating agent was applied with a roll coater onto an oriented polyester film (PET-N) having a thickness of 100 μm and 140 mm × 200 mm so as to have a dry film thickness of 4 μm, and dried at 80 ° C. for 60 seconds. Thereafter, it was cured by irradiating ultraviolet rays under a nitrogen stream (integrated light amount: 500 mJ / cm ³ ) with a 120 W high-pressure mercury lamp (manufactured by Nippon Battery Co., Ltd.) to produce a fingerprint-resistant film for display. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 2H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

(Example 2)
Polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 3) 40 parts by mass Dipentaerythritol hexaacrylate (DPHA) 60 parts by mass
1-hydroxycyclohexyl phenyl ketone 7.5 parts by weight MIBK 100 parts by weight

  The said raw material was mixed and it was set as the coating agent. This coating agent was cured according to Example 1 to produce a fingerprint-resistant film for display. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 2H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

Example 3
Polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 9) 30 parts by mass Dipentaerythritol triacrylate (DPHA) 70 parts by mass
1-hydroxycyclohexyl phenyl ketone 7.5 parts by weight MIBK 100 parts by weight

The said raw material was mixed and it was set as the coating agent. This coating agent was applied on a 100 μm-thick 140 mm × 200 mm oriented polyester film (PET-N) with a roll coater so that the dry film thickness was 8 μm, and dried at 80 ° C. for 60 seconds. Thereafter, it was cured by irradiating ultraviolet rays under a nitrogen stream (integrated light amount: 500 mJ / cm ³ ) with a 120 W high-pressure mercury lamp (manufactured by Nippon Battery Co., Ltd.) to produce a fingerprint-resistant film for display. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 3H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

Example 4
Polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 3) 40 parts by mass Dipentaerythritol triacrylate (DPHA) 60 parts by mass
1-hydroxycyclohexyl phenyl ketone 7.5 parts by weight MIBK 100 parts by weight

  The said raw material was mixed and it was set as the coating agent. This coating agent was cured according to Example 3 to produce a fingerprint-resistant film for display. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 3H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

(Example 5)
According to Example 1 except that polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 9) in Example 1 was changed to polypropylene glycol diacrylate (R = C ₃ H ₆ , n = 9). A fingerprint-resistant film for display was prepared. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 2H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

(Example 6)
According to Example 1, except that the polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 3) in Example 2 was changed to polypropylene glycol diacrylate (R = C ₃ H ₆ , n = 3). A fingerprint-resistant film for display was prepared. The fingerprint-resistant film for display had a haze of 0.2, an abrasion resistance of A, and a pencil hardness of 2H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

(Example 7)
According to Example 3 except that the polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 9) of Example 3 above was changed to polypropylene glycol diacrylate (R = C ₃ H ₆ , n = 9). A fingerprint-resistant film for display was prepared. The fingerprint-resistant film for display had a haze of 0.2, an abrasion resistance of A, and a pencil hardness of 3H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

(Example 8)
According to Example 4 except that the polytetramethylene glycol diacrylate (R = C ₄ H ₈ , n = 3) of Example 4 was changed to polypropylene glycol diacrylate (R = C ₃ H ₆ , n = 3). A fingerprint-resistant film for display was prepared. The fingerprint-resistant film for display had a haze of 0.1, an abrasion resistance of A, and a pencil hardness of 3H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

Example 9
A fingerprint-resistant film for display was produced according to Example 1, except that dipentaerythritol hexaacrylate of Example 1 was changed to an adduct of pentaerythritol triacrylate represented by the chemical formula (2) and hexamethylene isocyanate. . The fingerprint-resistant film for display had a haze of 0.3, an abrasion resistance of B, and a pencil hardness of 2H. The fingerprint visibility (reflection) was ◯, the fingerprint visibility (transmission) was ◯, the image visibility was ◯, and Nijimura was ◎.

Table 1 shows the measurement results of the compositions and physical properties of the above examples.

(Comparative Examples 1-10)
A fingerprint-resistant film for display was produced in the same manner as in Example 1 except that the materials to be mixed and the transparent substrate were described in Table 2 below. Here, PCMHA is polycyclohexyl methacrylate, and MX500 is cross-linked acrylic beads (manufactured by Soken Chemical Co., Ltd., average particle size 5.0 μm).

(Comparative Example 11)
Instead of the oriented polyester film (PET-N), a PET film “A4100” manufactured by Toyobo Co., Ltd. (retardation = 6200 nm, film thickness = 188 μm, Δn = 0.033) was used in the same manner as in Example 1, A fingerprint-resistant film for display was prepared.

Also for the anti-fingerprint film for each comparative example, haze, fingerprint visibility (reflection, transmission), image visibility, scratching property, pencil hardness, refractive index, film thickness, and Nizimura were measured and evaluated. The results are also shown in Table 2.

  In Examples 1 to 9 described in Table 1, the fingerprint attached to the coating layer was difficult to see, and the image visibility of characters and lines when placed on the display was good. Moreover, since the oriented polyester film was used as a transparent base film, Nizimura was not observed even through polarized sunglasses. On the other hand, fingerprints were visually recognized in Comparative Examples 5 to 7 shown in Table 2. Thereby, it turned out that the diacrylate which makes the fingerprint adhering on the smooth film surface inconspicuous is only the polyalkylene glycol diacrylate represented by the above chemical formula (1).

  In Comparative Examples 1 to 4 shown in Table 2, fingerprint visibility was good because the same polyalkylene glycol diacrylate as in Examples 1 to 9 was used, but pencil hardness, scratch resistance, etc. The physical properties of were bad. Thereby, in order to ensure the physical physical property of a film layer, it turned out that it is necessary to mix | blend an acrylate compound more than trifunctional. In Comparative Example 8, the haze value was large, and when installed on a display, the result was that the image visibility of characters, lines, and the like deteriorated. Thereby, when translucent fine particles were included in the coating layer as in the prior art, it was confirmed that the image visibility deteriorated.

Further, Comparative Example 9 was inferior in physical properties (pencil hardness), and Comparative Example 10 resulted in the result that the fingerprint attached to the coating layer was clearly visible. Thereby, the compounding ratio of (A) polyalkylene glycol diacrylate and (B) trifunctional or higher acrylate compound is at least 20:80 to 50:50 in mass parts of (A): mass parts of (B). (However, the mass part of (A) + the mass part of (B) = 100) could be derived. Furthermore, in Comparative Example 11, since a general-purpose polyester film was used as the transparent substrate film, Nizimura was also observed visually.

Claims (3)

(A) a polyalkylene glycol diacrylate represented by the following chemical formula (1);
(B) a trifunctional or higher functional acrylate compound;
(C) a photopolymerization initiator,
The mass part of (A): the mass part of (B) is 20:80 to 50:50 (provided that the mass part of (A) + the mass part of (B) = 100),
For a total of 100 parts by mass of (A) and (B), a coating layer containing 1 to 10 parts by mass of (C) is provided on the transparent substrate film,
The transparent base film has a refractive index (nx) in the direction having the highest refractive index (slow axis direction) and a refractive index in the direction orthogonal to the slow axis direction (fast axis direction). A fingerprint-resistant film for display, which is an oriented polyester film having a difference (nx−y) from (ny) of 0.07 to 0.20.

  The anti-fingerprint film for display according to claim 1, wherein the trifunctional or higher acrylate compound (B) is an ester compound of trifunctional or higher alcohol and (meth) acrylic acid. A display in which the fingerprint-resistant film for display according to claim 1 or 2 is disposed on a display screen.