JP2006007434A - Antireflection film laminate and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film laminate suitable for transfer being a thin film and not necessarily requiring a base material film for a support. <P>SOLUTION: This manufacturing method of the antireflection film laminate is composed of a process for coating a release film (A) with a radical curable composition for an antireflection layer to form a radical curable antireflection layer, a process for coating the antireflection layer with a composition for a hard coat layer to form the hard coat layer and a process for performing the radical curing of the radical curable composition for the antireflection layer. The antireflection film laminate is formed by laminating the hard coat layer under the antireflection layer and constituted so that the non-antireflection layer of the hard coat layer is freely transferred to an article to be subjected to antireflection treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laminate in which an antireflection film can be formed by transfer, and a method for producing the laminate.

  The anti-reflective coating is formed as the outermost layer of these devices in order to prevent the reflection of light on the screens of mobile communication devices such as televisions and office automation equipment, mobile phones, windows, and automobile glass. The antireflection effect is achieved by the difference in refractive index and the film thickness between the antireflection film and the hard coat layer below it.

  The antireflection film can be formed by directly forming a hard coat layer and an antireflection layer on the glass substrate, or transferring a film prepared separately for the antireflection film to a glass substrate. It is roughly divided into how to do.

  In the latter transfer method, a laminated film such as a release film, an antireflection layer, a hard coat layer, a base film (reinforcing layer) and, if necessary, an adhesive layer is usually used from the outermost surface side to a base material such as glass. The antireflection film is formed by closely adhering to the film and peeling the release film.

  In this case, the antireflection layer is a resin layer having a low refractive index, and is usually formed by curing the resin by a radical reaction. In some cases, the hard coat layer also uses a radical curable composition.

  In the antireflection film laminate for transfer, a hard coat layer is usually formed to a thickness of about 1 to 10 μm on a base film (PET film) having a thickness of about 25 to 1000 μm, and then the antireflection layer is formed to a thickness of 50. The film is applied to ˜150 nm, irradiated with active energy rays such as ultraviolet rays or heated in accordance with the curing system to cure the antireflection layer, and then a release film is applied to manufacture.

  However, the transfer laminate obtained in this way has a large overall film thickness, and it is difficult to affix it to a structure having a surface with fine irregularities or a curved surface. Further, there is a problem that the adhesion between the hard coat layer and the antireflection layer is insufficient.

  Therefore, in Patent Document 1, a laminate in which an antireflection layer is formed on a release film and a laminate in which a hard coat layer is separately formed on a base film are laminated with an antireflection layer and a hard coat layer, Thereafter, a method of curing the antireflection layer with ionizing radiation has been proposed.

  However, in the method of Patent Document 1, a substrate film having a sufficient thickness is necessarily required to support the hard coat layer, and the limitation on the shape of the transfer surface due to the large film thickness has not been solved. Further, the adhesion between the laminate surfaces of the antireflection layer and hard coat layer formed separately is insufficient, and the antireflection layer surface may be disturbed when the release film is peeled off.

Japanese Patent No. 3369684

  An object of this invention is to provide the anti-reflective film laminated body suitable for the transfer which is a thin film and does not necessarily require the support base film.

  That is, the present invention relates to an antireflection film laminate in which a hard coat layer is laminated under an antireflection layer, and the non-antireflection layer side of the hard coat layer is configured to be transferred to an antireflection treatment product.

  A release film (A) may be laminated on the antireflection film, or a release film (B) may be further laminated on the non-reflection layer side of the hard coat layer. Good.

  The present invention also includes a step of applying a radical curable composition for an antireflection layer on the release film (A) to form a radical curable antireflection layer, and a composition for a hard coat layer on the antireflection layer. The present invention relates to a method for producing an antireflection film laminate comprising a step of coating to form a hard coat layer and a step of radical curing of the radical curable composition for an antireflection layer.

  In this production method, it is preferable to perform a step of precuring the radical curable antireflection layer before applying the hard coat layer composition.

  According to the present invention, it is possible to provide an antireflection film that can be applied to a surface with fine irregularities and that is uniform even with a thin film.

  The antireflection film laminate suitable for transfer according to the present invention has a hard coat layer laminated under the antireflection layer, and the non-antireflection layer side of the hard coat layer can be transferred to an antireflection treatment object. Has been. As described above, the antireflection film laminate of the present invention does not have a support layer that has been an indispensable layer in the past, and is configured such that the hard coat layer can be directly transferred to an antireflection treatment product.

  Conventional materials and film thicknesses for the antireflection layer and the hard coat layer can be employed. These will be described later in the manufacturing method.

  The laminate of the present invention may be protected by providing release films (A) and (B) on the surface of the layer before transfer. The release film will also be described in detail in the description of the production method.

The production method of the present invention comprises:
(I) a step of applying a radical curable composition for an antireflection layer on the release film (A) to form a radical curable antireflection layer;
(II) The process of apply | coating the composition for hard-coat layers on this antireflection layer and forming a hard-coat layer, and the process of performing the radical hardening of the radical curable composition for this (III) antireflection layer.

  Each step will be described.

  As the release film (A) used in the radical curable antireflection layer forming step (I), a conventionally used resin film can be used, but in order to perform a radical curing reaction in a low oxygen atmosphere described later. A resin film that does not substantially transmit oxygen is preferably employed.

  In order to smooth the surface of the antireflection layer after peeling, the release film (A) can be easily peeled off from the cured antireflection layer and has a smooth surface. The thickness is usually about 10 to 100 μm. Specific examples of the release film will be described later.

  On the release film (A), a radical curable composition for an antireflection layer is applied to form a radical curable antireflection layer.

  As the radical curable composition for the antireflection layer, a conventionally known radical curing reactive composition can be used. In addition, a curable surface modifier described in Japanese Patent Application No. 2003-355455 can also be used.

  Even if the radical curing reaction is an active energy curing reaction in which curing is initiated by active energy rays such as ultraviolet rays, X-rays, γ-rays, and electron beams, heating is started by heating using a known radical reaction initiator. Although it may be a curing reaction, an active energy ray curing reaction system is preferable from the viewpoint of less selection of the substrate and less layer modification.

  The radical curable composition of the active energy ray curable reaction system is preferably a composition of an active energy ray curable resin and a photocuring accelerator or a photosensitizer.

  Examples of the active energy ray-curable resin include monofunctional acrylates, bifunctional acrylates, polyfunctional acrylates, polyester acrylates, urethane acrylates, epoxy acrylates, and imide acrylates.

  Examples of photocrosslinking agents include trimethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol. In addition to polyfunctional monomers such as hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, triallyl isocyanurate, triallyl cyanurate, dipentaerythritol, pentahexa Examples of the photoinitiator include acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetramethylthiura. Monosulfides, thioxanthones, acylphosphine oxides, O-acyloximes and the like. Examples of photosensitizers include n-butylamine, triethylamine, tri-n-butylphosphine, methyldiethanolamine, 4-dimethylaminobenzoate. Examples include ethyl acetate, isoacyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.

  In addition, a conventionally known additive used for forming an antireflection film may be blended.

  These are dissolved or dispersed in an organic solvent to form a coating composition, which is applied to the release film (A). As the organic solvent, general-purpose solvents such as ketone solvents, acetate solvents and alcohol solvents can be preferably used. The curable surface modifier described in the above-mentioned Japanese Patent Application No. 2003-355455 is particularly excellent in solubility in such general-purpose solvents and is preferable as a material for an antireflection film.

  Application to the release film (A) is a bar coating method, roll coating method, dip coating method, spin coating method, reverse roll coating method, direct gravure method, gravure reverse method, lip coating method, micro gravure method, etc. Can be performed. The coating amount is preferably such that the thickness of the antireflection layer after drying is 50 to 150 nm, more preferably 80 to 120 nm. If necessary after application, a drying step may be performed.

  Further, prior to the hard coat layer forming step (II), a step (IA) of precuring the formed uncured antireflection layer may be performed. By applying this pre-curing step (IA), it is difficult to be affected by the formation of the hard coat layer, and this is desirable in that the antireflection layer is kept homogeneous and surface smooth. This preliminary curing is performed by a curing method according to the radical curing reaction system of the composition.

  The degree of pre-curing (curing degree) may be arbitrarily selected, but as a guideline, it is sufficient that the antireflection layer does not adhere to other materials during processing or the uniformity of film thickness is not impaired. For example, it is desirable to carry out until 5% or more, preferably 20% or more, of the curing site of the radical curable composition in the antireflection layer is consumed. However, it is the curing step (III) described later that completely cures, and therefore, the curing sites remain at 95% or more, preferably 80% or more.

  In the active energy ray curing system, a dose of 5 to 80%, preferably about 10 to 20% of the dose of active energy rays necessary for complete curing is irradiated.

  The degree of curing can be determined by the intensity of characteristic absorption at the curing site in IR analysis. When the characteristic absorption disappears, it is in a fully cured state.

  Next, the step (II) of forming the hard coat layer by applying the hard coat layer composition onto the thus formed uncured or incompletely precured antireflection layer is performed.

  The hard coat layer composition is a composition made of a resin having a refractive index higher than that of the antireflection layer, and a conventionally known composition can be used. It is preferable that this hard coat layer composition is also radically curable because of its excellent hardness, mechanical strength, and the like. Specifically, a relatively low molecular weight polyester resin, polyether resin, acrylic resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin, polyfunctional compound (meta ) Active energy ray-curable composition in which a monofunctional monomer such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone or the like is blended with an acrylate oligomer or prepolymer as a reactive diluent Examples: lauryl acrylate, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether and the like. The active energy ray-curable composition is preferably blended with the photocrosslinking agent, photoinitiator, or photosensitizer.

  Application to the antireflection layer should be performed by methods such as bar coating, roll coating, dip coating, spin coating, reverse roll coating, direct gravure, gravure reverse, lip coating, and micro gravure. Can do. The coating amount is preferably such that the thickness of the hard coat layer after drying is 1 to 10 μm, more preferably 4 to 6 μm. If necessary after application, a drying step may be performed.

  Thus, a laminate composed of the release film (A) + antireflection layer + hard coat layer is formed.

  The step of completing the radical curing reaction for the laminate based on this structure is step (III).

  The curing reaction in the radical curing step (III) may be active energy ray curing as described above, or may be heat treatment, but active energy ray curing is preferred for the reasons described above.

  By the way, it is known that in the radical curing reaction, the presence of oxygen inhibits the curing reaction. Therefore, conventionally, curing is performed using a curing atmosphere having a low oxygen concentration. For example, in JP-A-11-268240, curing is performed in an atmosphere filled with an inert gas (nitrogen gas in the embodiment).

  In the present invention, since the antireflection layer is sandwiched between the release film (A) and the hard coat layer, by using a material that does not substantially transmit oxygen as the release film (A), A curing reaction can be carried out, which is advantageous both in terms of process and equipment.

The fact that oxygen does not substantially permeate is only required to maintain the oxygen concentration in the composition to be cured to an extent that does not cause curing (crosslinking) inhibition, and does not require high oxygen impermeability. For example, in the form of a film, the oxygen permeability (JIS K7126) is 50,000 cm ³ / m ² · day · 1 atm (23 ° C., 65% RH; the same applies hereinafter) or less, and 20,000 cm ³ / m ² · Day · 1 atm or less, further 5,000 cm ³ / m ² · day · 1 atm or less, particularly 1,000 cm ³ / m ² · day · 1 atm or less are suitable. The lower limit is better, but usually 1 cm ³ / m ² · day · 1 atm or more is preferable.

  Specific examples of the release film material that does not substantially transmit oxygen include polyester, polycarbonate, polysulfone, polyether, trimethylpentene, polyetherketone, (meth) acrylonitrile, triacetylcellulose, diacetylcellulose, acetate butyrate. Rate cellulose, polyethersulfone, polyacrylic resin, polyurethane resin, low density polyethylene, polyvinyl chloride, polyvinylidene chloride, polyamide, polypropylene, ethylene / alcohol copolymer, polytetrafluoroethylene, ethylene Trifluoroethylene / perfluoro (alkyl vinyl ether) copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, Rifu' fluoride, fluorine resin and fluorine rubber such as polychlorotrifluoroethylene; aluminum deposited film in the case of heat curing type, polyimide, urea resin, etc. The fluorine resin. If the material itself does not have releasability, a release agent such as silicone resin, fluororesin, or acrylic-melamine resin may be applied or coated on these films to impart releasability.

  In addition, when the hard coat layer is a radical curable composition and is cured simultaneously with the antireflection layer, the outer surface of the hard coat layer is covered with a protective layer that does not substantially allow oxygen to pass through, thereby blocking oxygen. A curing reaction can be performed.

  A release film (B) can be illustrated as an example of the protective layer that does not substantially allow oxygen to permeate. Of course, other resin films, resin layers, etc. can be exemplified, and those corresponding to the conventional base (support) film include those that do not substantially permeate oxygen, but the thickness can be significantly thinner than before. It may be about 10 nm to 75 μm. Of course, depending on the application, it may be thick as in the prior art. The release film (B), the resin film, and the resin layer as the protective layer may serve not only for the curing reaction but also as a reinforcing layer or an adhesive layer. As the release film (B), the resin film, and the resin layer as a protective layer that does not substantially transmit oxygen, the material of the release film (A) that does not substantially transmit oxygen can be used as appropriate.

  The protective layer may be a liquid. In this case, a substance that can be present only during the curing reaction and can be easily removed after the reaction is preferable. Such a liquid that does not substantially permeate oxygen preferably has an oxygen saturation solubility (dissolved oxygen mass / solution mass) of 1000 ppm (25 ° C. or lower). For example, fluorine oil, solvent oil, liquid paraffins, higher alcohols , Polysaccharides, gelatin and the like.

  Furthermore, for the purpose of temporarily blocking oxygen during the curing reaction, a material that does not substantially transmit oxygen may be temporarily placed on the hard coat layer. Examples of such materials include various nonwoven fabrics, woven fabrics, felts, webs, etc., which contain an oxygen absorbent. These are removed after the curing process.

  These protective layers are desirably materials that do not participate in the curing reaction. Accordingly, the release films (A), (B) and the protective layer are preferably transparent to the active energy ray if they are active energy ray curable systems, and are preferably heat resistant if they are heat curable systems. In the case of an active energy ray curing system, the irradiation of active energy rays may be from the release film (A) side or from the hard coat layer (release film (B) or protective layer) side.

  In the present invention, an adhesive layer, a printing layer, and the like may be appropriately formed on the hard coat layer or the protective layer (reinforcing layer). When the hard coat layer or the protective layer has an affinity (adhesion) with the surface material of the article to be transferred, firm adhesion can be obtained without providing an adhesive layer.

  The curing step (III) in the present invention may be performed before the transfer, or may be performed after the transfer, in a state of being transferred to an article on which an antireflection film is to be formed.

  The antireflection film laminate of the present invention is not limited to the production method as described above, for example, a hard coat layer is formed on the release film (B), and an antireflection layer is formed on the hard coat layer, You may manufacture by forming a release film (A) on this hard-coat layer.

  Examples of the base material of the article on which the antireflection film is to be formed include a glass substrate, a transparent plastic substrate, and a silicon rubber touch panel.

  What is necessary is just to select the irradiation dose in the case of active energy ray hardening suitably according to the kind of curable composition, the thickness of a layer, etc. The conditions for curing by heating may be appropriately selected depending on the curing system (peroxide curing, cationic curing, etc.). The case of performing preliminary curing is as described above.

  As a transfer method, a conventionally known transfer method such as a vacuum compression molding method or a calendar method can be employed. Of course, if you have the skill, you can do it manually. In particular, according to the present invention, it is possible to produce a thin antireflection film laminate for sticking, so surface followability is good even for articles with fine irregularities, cell phone dials, lenses, operation panels of various devices, etc. In addition to its anti-reflective function, it has an excellent finished appearance.

  Further, after the transfer, surface disturbance that may occur when the release film (A) is peeled off is, for example, surface modification such as a curable surface modifier described in Japanese Patent Application No. 2003-355455. It can be repaired by applying an agent.

  Next, several preferred embodiments of the production method of the present invention and further steps up to transfer (formation of an antireflection film) will be shown, but the present invention is not limited to these embodiments.

Embodiment 1:
(1-1) An antireflection layer is formed on the release film (A).
(1-2) The antireflection layer is pre-cured incompletely by irradiating active energy rays from the opposite side of the release film (A).
(1-3) A hard coat layer is formed on the antireflection layer.
(1-4) A protective release film (B) is stuck on the hard coat layer.
(1-5) The active energy ray is irradiated from the release film (B) side to completely cure the antireflection layer and the hard coat layer.
(1-6) The release film (B) is removed, an adhesive layer (a release paper may be further attached if necessary) is formed on the hard coat layer, and an article (glass substrate) is formed on the adhesive layer side. The release film (A) is peeled off.

Embodiment 2:
(1-1) A hard coat layer is formed on the release film (B).
(1-2) An antireflection layer is formed on the hard coat layer.
(1-3) The antireflection layer is pre-cured incompletely by irradiating active energy rays from the opposite side of the hard coat layer.
(1-4) Affix the release film (A) on the antireflection layer.
(1-5) The active energy ray is irradiated from the release film (A) side to completely cure the antireflection layer and the hard coat layer.
(1-6) The release film (B) is removed, an adhesive layer (a release paper may be further attached if necessary) is formed on the hard coat layer, and an article (glass substrate) is formed on the adhesive layer side. The release film (A) is peeled off.

The antireflection film laminate for sticking of the present invention can impart an antireflection function and an antifouling function to the following articles, for example.
Home appliances: TVs, microwave oven windows, various display boards for home appliances, anti-reflection for design purposes of the outer plate.
OA equipment: various monitors, sensor parts, operation panel (button) surface, antireflection for design purposes of the outer plate part, etc.
Mobile communication equipment: Anti-reflection for design purposes such as LCD screen of mobile phone, operation button surface, outer plate part.
Architectural: windows, signboards, show window glass, curved mirrors, traffic light lenses, etc.
Vehicle-related: Automobile / train glass, door mirrors, meter panel protection plates, display surfaces, etc.
Interior: mirrors, showcases, blinds, walls, ceilings, floors, furniture surfaces, etc.
Exterior related: Neon signs, gates, shutters, various exterior surfaces, etc.
Optical equipment: Eyeglass lenses, various lenses, sensor units, etc.
Design indications: Signboards, neon signs, show windows, etc.
Other: Clock face etc.

  EXAMPLES Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited only to these examples.

Example 1
A spin coater on a release film (A) in which a silicone oil is applied as a release agent to a polyvinylidene chloride film (thickness 20 μm, oxygen permeability 55 cm ³ / m ² · day · 1 atm: 23 ° C.-65% RH) Then, the next UV curable composition for the antireflection layer was applied and dried at room temperature for 20 minutes (film thickness 107 nm). The film thickness was measured using an optical film thickness meter (manufactured by FILMETRICS) (the same applies hereinafter).

(Composition for antireflection layer)
Crosslinker (dipentaerythritol penta / hexa-acrylate) and photoinitiator (Irgacure, trade name, manufactured by Ciba Specialty Chemicals) mixed with functional group-containing fluorine-containing resin (OPTOOL AR-110, manufactured by Daikin Industries, Ltd.) The solid content concentration is adjusted to 4% by mass with methyl isobutyl ketone.

Next, the antireflection layer was pre-cured by irradiating with an ultraviolet ray of 200 mJ / cm ² using a high-pressure mercury lamp (illuminance 165 mW / cm ² ) (the dose for completely curing the antireflection layer is 1 J / cm ² ). .

  A hard coat layer composition (acrylic resin-based KRX-559 manufactured by Asahi Denka Kogyo Co., Ltd.) was applied on the pre-cured antireflection layer with a bar coater to form a hard coat layer (thickness 5 μm). .

On this hard coat layer, a release film (B1) made of polyethylene terephthalate (PET) (thickness 25 μm, oxygen permeability 72 cm ³ / m ² · day · 1 atm: 23 ° C.-65% RH) was placed as a protective layer, Using a high pressure mercury lamp, ultraviolet rays were irradiated at 2000 mJ / cm ² to completely cure the antireflection layer and the hard coat layer, thereby producing an antireflection film laminate.

  Next, after removing the release film (B1), a pressure-sensitive adhesive was applied onto the hard coat layer, and the laminate was affixed to the surface of a polycarbonate molded body having a non-smooth surface using a vacuum compression molding apparatus. It was affixed along the irregularities cleanly.

The release film (A) was peeled from the stuck laminate, and the following characteristics were examined for the antireflection layer that was the outermost layer. The results are shown in Table 1.
(1) Contact angle with water Measured with a CA-DT • A contact angle meter manufactured by Kyowa Interface Science Co., Ltd.
(2) Surface hardness Pencil hardness is measured according to JIS K5400.
(3) Haze value The haze value at the initial stage and after the abrasion test (with steel wool attached to the Haydon abrasion meter and reciprocating 30 times on the antireflection layer with a load of 200 g / cm ² ) is measured with a haze meter according to JIS K7105.
(4) Curing degree The change in absorption intensity of the characteristic absorption (1647 to 1640 cm ⁻¹ ) of the C═C double bond of the used crosslinking agent was analyzed with an IR spectrophotometer, and the curing degree (crosslinking was calculated from the consumption ratio of the crosslinking agent. Degree). The absorbance before pre-curing of the antireflection layer (when dried for 20 minutes) is 100%.

Example 2
The film thickness of the antireflection layer is 113 nm, and the release film (B2) made of (PE) is used as the release film (B) (thickness 25 μm, oxygen permeability 13,000 cm ³ / m ² · day · 1 atm: 23 ° C. A laminate of the present invention was produced in the same manner as in Example 1 except that -65% RH) was used, and the characteristics were examined in the same manner as in Example 1. The results are shown in Table 1.

Claims (5)

An antireflection film laminate in which a hard coat layer is laminated under an antireflection layer, and a non-antireflection layer side of the hard coat layer is configured to be transferred to an antireflection treatment product. The laminate according to claim 1, wherein a release film (A) is laminated on the antireflection film. The laminated body of Claim 1 or 2 with which the release film (B) is laminated | stacked on the non-reflection prevention layer side of the said hard-coat layer. A step of applying a radical curable composition for an antireflection layer on the release film (A) to form a radical curable antireflection layer, and a hard coat by applying a composition for a hard coat layer on the antireflection layer A process for producing an antireflection film laminate comprising a step of forming a layer and a step of radical curing of the radical curable composition for an antireflection layer. The manufacturing method of Claim 4 which performs the process of precuring a radical-curable antireflection layer before apply | coating the said composition for hard-coat layers.