Infrared cut hard coat film

Abstract

To provide an infrared cut film which does not contain an organic fluorine compound.SOLUTION: There is provided an infrared cut film in which an infrared absorption layer is laminated on a transparent base material. The infrared absorption layer is a cured product of a resin composition containing an infrared absorption component, an acrylic compound not containing fluorine and silicone, an acrylic compound not containing fluorine but containing silicone, and a photoinitiator.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a hard coat film having a heat shielding function by blocking infrared rays. [Background technology]

[0002] In recent years, there has been growing interest in head-up displays (HUDs), which display driving support information for the driver on the windshield of a vehicle, and some vehicle models are being equipped with them. The most common method of realizing a HUD is to project an image from a display unit onto the windshield. However, this method has the problem that the image display devices that make up the display unit, such as LCD elements, are prone to becoming hot and thermally degraded because sunlight from the windshield is concentrated on the display unit, and so there is a demand for heat insulation for the display unit.

[0003] Here, image data projected from the image display device is reflected and magnified by a magnifying mirror through a diffuser plate and displayed on the windshield through a cover film. Therefore, using an infrared-cut film coated with a composition that absorbs infrared rays as a heat-shielding material for such a cover film is useful as a heat-shielding measure.

[0004] As such a heat shielding film, for example, a heat shielding film has been proposed that has an infrared absorbing layer containing an oxide having infrared absorbing ability, an acrylic compound that does not contain fluorine, and an acrylic compound that contains fluorine on a transparent substrate with a retardation value of 100 nm or less (Patent Document 1). Organic fluorine compounds (hereinafter referred to as PFAS) used here generally exhibit good physical properties such as water repellency, oil repellency, and thermal and chemical stability. Therefore, they are widely used in the field of coating agents such as optical film applications. On the other hand, PFAS is problematic due to its recalcitrance and bioaccumulation, and there is a movement to regulate its use, mainly in Europe. Therefore, there was a demand for an infrared cut film that can obtain the same level of properties without using PFAS. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7241324 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides an infrared-cutting film that does not contain PFAS. [Means for solving the problem]

[0007] The invention described in claim 1 provides an infrared-cutting film comprising an infrared-absorbing layer laminated on a transparent substrate, the infrared-absorbing layer being a cured product of a resin composition containing: an infrared-absorbing component (A); an acrylic compound (B) that is free of fluorine and silicone; an acrylic compound (C) that is free of fluorine and contains silicone; and a photopolymerization initiator (D).

[0008] A second aspect of the present invention provides the infrared ray blocking film according to the first aspect, wherein the transparent substrate has a retardation value of 100 nm or less.

[0009] The invention as recited in claim 3 provides the infrared-cutting film as recited in either one of claims 1 or 2, characterized in that (C) is an acrylic (meth)acrylate having a silicone side chain on an acrylic main chain. Effect of the Invention

[0010] The hard-coated film of the present invention has a sufficient heat-shielding effect by blocking infrared rays, and at the same level of dynamic / static friction coefficient can be obtained without blending PFAS. As a result, scratch resistance and pencil hardness can be improved, making it useful as an environmentally friendly infrared-blocking hard-coated film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below.

[0012] The resin composition used in the present invention is composed of an infrared absorbing component (A), an acrylic compound (B) that does not contain fluorine and silicone, an acrylic compound (C) that does not contain fluorine but contains silicone, and a photopolymerization initiator (D). In this specification, the term "(meth)acrylate" includes both acrylate and methacrylate.

[0013] The infrared absorbing component (A) used in the present invention refers to a component that selectively absorbs a specific wavelength region mainly in the near infrared region (750 to 1000 nm) and exhibits a strong absorption and shielding effect against heat by blending with a binder, and examples thereof include cesium tungsten oxide, tin indium oxide, antimony tin oxide, lanthanum hexaboride, diimonium salts, etc. Among these, cesium tungsten oxide, which is relatively low cost and has a high absorption coefficient, is preferred.

[0014] Cesium tungsten oxide has a strong absorption in the infrared region, particularly in the range of 800 nm to 1200 nm, and its chemical formula is generally Cs 0.33 It is an inorganic nanoparticle represented by WO3. The average particle size is preferably 1 to 50 nm, more preferably 5 to 35 nm. By setting it in this range, it is possible to maintain a good balance between high visible light transmittance and infrared absorption performance. An example of a commercially available cesium tungsten oxide infrared absorber is YMF02 (product name: manufactured by Sumitomo Metal Mining Co., Ltd., average particle size 15 nm, solid content 18.5%). The average particle size can be measured by a particle size distribution measuring device based on the dynamic light scattering method using laser light.

[0015] The amount of (A) based on the total solid content is preferably 5 to 55% by weight, more preferably 10 to 40% by weight, and particularly preferably 15 to 30% by weight. By making it 5% by weight or more, a heat shielding effect by blocking infrared rays can be obtained, and by making it 55% by weight or less, sufficient visible light transmittance can be obtained.

[0016] The fluorine- and silicone-free acrylic compound (B) used in the present invention is a binder for (A) and is also a main component constituting the coating. Examples of oligomers include acrylic resin binders such as urethane (meth)acrylate (hereinafter referred to as ureac), epoxy (meth)acrylate, polyester (meth)acrylate, polycarbonate (meth)acrylate, acrylic (meth)acrylate, and diene (meth)acrylate, and these can be used alone or in combination of two or more kinds.

[0017] A low molecular weight binder may be used as a component other than the oligomer. For example, (meth)acrylates having functional groups such as aliphatic, alicyclic, polyether skeleton, hydroxyl group, and amino group, and acrylamide compounds can be used alone or in combination of two or more. The number of functional groups is preferably multifunctional in terms of reactivity. For example, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, etc. can be mentioned.

[0018] The blending amount of (B) is preferably 30 to 90% by weight, more preferably 50 to 85% by weight, and particularly preferably 60 to 80% by weight, based on the total solid content. By making it 30% by weight or more, sufficient film cohesion can be ensured, and by making it 90% by weight or less, a good balance between high visible light transmittance and infrared ray absorption performance can be maintained.

[0019] The fluorine-free silicone-containing acrylic compound (C) used in the present invention is blended as an alternative component to PFAS in order to reduce the coefficient of friction of the cured product, and as a result, the steel wool resistance and pencil hardness can be increased. For example, (meth)acrylates and urethane (meth)acrylates having a silicone skeleton such as polyalkylsiloxane, polyarylsiloxane, polyalkylarylsiloxane, polyester-modified siloxane, and polyether-modified siloxane can be mentioned, and can be used alone or in combination of two or more kinds. By having a reactive (meth)acryloyl group in the molecule, it is firmly bonded with (B), suppressing the occurrence of bleed-out over time, and imparting good slip properties and abrasion resistance to the surface of the cured product for a long period of time. Specifically, acrylic (meth)acrylates having silicone side chains on the acrylic main chain, urethane (meth)acrylates containing urethane bonds on the silicone main chain, etc. can be mentioned.

[0020] The blending amount of the (C) is preferably 0.05 to 30% by weight, more preferably 0.1 to 20% by weight, based on the total solid content. By making it 0.05% by weight or more, it is expected that the dynamic friction coefficient can be reduced, and by making it 30% by weight or less, a good balance between high visible light transmittance and infrared ray absorption performance can be maintained.

[0021] The photopolymerization initiator (D) used in the present invention generates radicals when irradiated with ultraviolet light or an electron beam, and the radicals trigger the polymerization reaction, and general-purpose photopolymerization initiators such as benzyl ketals, acetophenones, phosphine oxides, and oxime esters can be used. By arbitrarily selecting the light absorption wavelength of the polymerization initiator, it is possible to impart curability over a wide wavelength range from the ultraviolet region to the visible light region. Specifically, benzyl ketals include 2.2-dimethoxy-1.2-diphenylethan-1-one, α-hydroxyacetophenones include 1-hydroxy-cyclohexyl-phenyl-ketone and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, α-aminoacetophenones include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, acylphosphine oxides include 2.4.6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2.4.6-trimethylbenzoyl)-phenylphosphine oxide, and oxime esters include ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl], 1-(o-acetyloxime), etc., which can be used alone or in combination of two or more. Among these, it is preferable to use an α-hydroxyacetophenone type that is less prone to yellowing, or an oxime ester type that has an absorption band on the long wavelength side. Commercially available products include Omnirad 184 and 2959 (product names: manufactured by iGM Resins, α-hydroxyacetophenone type), and Irgacure OXE04 (product name: manufactured by BASF Japan, oxime ester type).

[0022] The ratio of (D) to 100 parts by weight of the ultraviolet curable resin component is preferably 1 to 10 parts by weight, more preferably 3 to 8 parts by weight. By adding 1 part by weight or more, sufficient curability is exhibited, and by adding 10 parts by weight or less, yellowing of the coating film and deterioration of storage stability can be prevented without excessive addition.

[0023] The hard coat resin forming the infrared-cut hard coat layer of the present invention may be diluted with a solvent to a solid content of 10 to 70% in order to improve the coating property to a thermoplastic transparent substrate film. Examples of the solvent include alcohol-based solvents such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and diacetone alcohol, ketone-based solvents such as acetone, methyl ethyl ketone (hereinafter MEK), methyl isobutyl ketone (hereinafter MIBK), and cyclohexanone, ester-based solvents such as methyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate (hereinafter PGMEA), and ether-based solvents such as propylene glycol monomethyl ether (hereinafter PGM), diethyl ether, and diisopropyl ether, and may be used alone or in combination of two or more kinds.

[0024] In addition, the photocurable resin composition of the present invention can further contain additives such as an antifingerprint agent, an antioxidant, an ultraviolet absorber, a sensitizer, a flame retardant, a filler, organic fine particles, inorganic fine particles, a dispersant, a silane coupling agent, an antifoaming agent, an antistatic agent, an antibacterial agent, an antiviral agent, a polymerization inhibitor, a colorant such as a pigment, a dye or a coloring material, and a plasticizer, as necessary, within a range that does not impair the performance.

[0025] The transparent substrate used in the infrared cut film of the present invention preferably has a retardation value of 100 nm or less, more preferably 50 nm or less. By making the retardation value 100 nm or less, rainbow unevenness is unlikely to occur in the image projected through the transparent substrate, and the brightness is also stable. The retardation value of the transparent substrate being 100 nm or less means that the retardation value is 100 nm or less in each of the thickness direction, width direction, and length direction of the transparent substrate.

[0026] Examples of the substrate film used in the infrared cut film of the present invention include acrylic (PMMA) film, polycarbonate film (hereinafter referred to as PC), cycloolefin (co)polymer film, and composite films thereof. Among these, PMMA film and PC film are preferred because of their excellent weather resistance and transparency. In particular, composite films formed by laminating these films are preferred because the PMMA side, which has excellent weather resistance and hardness, can be used on the windshield side, and the PC side, which has excellent heat resistance and mechanical strength, can be used on the image element device side.

[0027] The thickness of the substrate film is not particularly specified and can be selected as required, but is preferably 30 to 500 μm, particularly preferably 50 to 400 μm, in terms of ease of handling and strength. Commercially available PMMA films include Parapure (product name: manufactured by Kuraray Co., Ltd.), Acriplene (product name: manufactured by Mitsubishi Chemical Co., Ltd.), Technoloy (product name: manufactured by Sumitomo Chemical Co., Ltd.), and Sunduren (product name: manufactured by Kaneka Corporation). Commercially available PC films include Carboglass film (product name: manufactured by Asahi Glass Co., Ltd.), Panlite film (product name: manufactured by Teijin Co., Ltd.), and Lexan (product name: manufactured by SABIC Corporation). PMMA / PC laminated films include Technoloy (product name: manufactured by Sumitomo Chemical Co., Ltd.), and Iupilon (product name: manufactured by Mitsubishi Gas Chemical Co., Ltd.).

[0028] The method for applying the hard coat resin of the present invention to the substrate film can be a known method such as a bar coater method, an applicator method, a curtain coater method, a roll coater method, a gravure coater method, a reverse coater method, a comma coater method, a lip coater method, a die coater method, etc. The coating film thickness is generally 1 to 20 μm as a dry film thickness, but is not particularly specified and can be selected as needed.

[0029] After the hard coat resin is applied, it is dried at 60 to 120°C to volatilize the solvent, and then cured using an ultraviolet irradiator. As the light source, known light sources such as high pressure mercury lamps, medium pressure mercury lamps, low pressure mercury lamps, metal halide lamps, xenon lamps, LED lamps, and electrodeless ultraviolet lamps can be used, and the ultraviolet irradiation conditions are 500 mW / cm. 2~3,000mW / cm 2 The irradiation intensity is 100 mJ / cm2. 2 ~2,000mJ / cm 2 Examples include:

[0030] The present invention will be described in detail below based on examples and comparative examples, but these are specific examples and are not intended to be limiting. Unless otherwise specified, measurements were performed under conditions of room temperature of 25°C and relative humidity of 65%. The blending amounts are expressed in parts by weight calculated as solid content.

[0031] Example 1 In a light-shielding bottle, YFM02A (product name: manufactured by Sumitomo Metal Mining Co., Ltd., cesium tungsten oxide content 18.5% by weight) was placed as (A), DPHA (dipentaerythritol hexaacrylate) and DCP-A (product name: manufactured by Kyoeisha Chemical Co., Ltd., dimethylol-tricyclodecane diacrylate) as (B), 8SS-723 (product name: manufactured by Taisei Fine Chemical Co., Ltd., acrylic (meth)acrylate having a silicone side chain on an acrylic main chain) as (C), and Omnirad2959 (product name: manufactured by iGM Resins, α-hydroxyacetophenone type) and IrgacureOxe04 (product name: manufactured by BASF Japan, oxime ester type) as (D) were placed in the amounts shown in Table 1, diluted with PGM to a solid content of 28% by weight, and stirred for 15 minutes or more using a stirring defoamer until uniform, to prepare the resin composition of Example 1.

[0032] Examples 2 to 4, Comparative Examples 1 to 2 In addition to the materials used in Example 1, RS-57 (product name: DIC Corporation, silicone-based additive having a reactive acryloyl group), GL-04R (product name: Kyoeisha Chemical Co., Ltd., acrylic (meth)acrylate having a silicone side chain on an acrylic main chain), and EBECRYL350 (product name: Daicel-Allnex Corporation, silicone diacrylate) as (C), and X-71-1203M (product name: Shin-Etsu Chemical Co., Ltd.) as a fluorine-based acrylate were placed in a light-shielding bottle in the amounts shown in Table 1, and the mixture was diluted with PGM to a solid content of 28% by weight, and stirred for 15 minutes or more using a stirring defoamer until it became uniform, thereby preparing the resin compositions of Examples 2 to 4 and Comparative Examples 1 and 2.

[0033] Table 1 JPEG2025036814000001.jpg109170

[0034] Creating infrared blocking hard coat film Iupilon DF02U (product name: Mitsubishi Gas Chemical Company, PMMA / PC composite film, thickness 375 μm, retardation value less than 50 nm) was subjected to corona discharge treatment on the PMMA side (no corona treatment is necessary), and then the resin composition was applied to the film so that the dry film thickness was 2 μm. The film was then dried in a thermostatic chamber at 80°C for 1 minute, and then irradiated with ultraviolet light using high-pressure mercury at an output of 1,000 mW / cm2 and an accumulated light amount of 150 mJ to produce infrared-cutting hard coat films of Examples 1 to 4 and Comparative Examples 1 and 2.

[0035] The evaluation method was as follows.

[0036] Curability: Immediately after the hard coat film is made, the presence or absence of tackiness on the coating surface is confirmed by touching with the fingers. If there is no tackiness, it is marked as ◯, and if there is tackiness, it is marked as ×.

[0037] Adhesion: According to the old JIS K5400, a checkerboard test was performed on 10x10 grids of 1mm squares, and the peeling state of the coating was confirmed using cellophane tape (specified in JIS Z1522). When the cellophane tape attached to the coating side was peeled off, if 0 grids peeled off, it was marked as ○, and if even 1 grid was peeled off, it was marked as ×.

[0038] Static friction coefficient: Using Triboster TS 501, an automatic friction and wear analyzer manufactured by Triboster, measurements were taken twice under the following measurement conditions: load 100g, point contact, scanning distance 5cm, scanning distance 1cm / min, and the average value of the static friction coefficient (μk) was calculated. Less than 0.15 was marked with ◎, 0.15 to less than 0.20 was marked with ◯, and 0.20 or more was marked with ×.

[0039] Dynamic friction coefficient: Using Triboster TS 501, an automatic friction and wear analyzer manufactured by Triboster, measurements were taken twice under the following measurement conditions: load 100g, point contact, scanning distance 5cm, scanning distance 1cm / min, and the average value of the dynamic friction coefficient (μk) was calculated. Less than 0.08 was marked with ◎, 0.08 to less than 0.15 was marked with ◯, and 0.15 or more was marked with ×.

[0040] Pencil hardness: Measured in accordance with JIS K5600-5-4 (1999 edition) using a pencil scratch coating hardness tester (Model P) manufactured by Toyo Seiki Seisakusho Co., Ltd. under a load of 200 g.

[0041] Steel wool resistance: Using an abrasion tester manufactured by Toyo Seiki Co., Ltd., a 500g load was placed on steel wool #0000 with a contact area of ​​25mm diameter, and the tester reciprocated 10 times at a reciprocating speed of 100 times / min. The number of scratches was then visually confirmed, with no scratches being indicated as ◎, less than 5 scratches being indicated as ◯, and 5 or more scratches being indicated as ×.

[0042] Evaluation results Table 2 JPEG2025036814000002.jpg83135

[0043] The infrared-cutting hard coat films of the Examples obtained good results in all of the evaluation items of curability, adhesion, static friction coefficient, dynamic friction coefficient, pencil hardness, and steel wool resistance.

[0044] On the other hand, Comparative Example 1 was a formulation containing PFAS, and Comparative Example 2, which did not contain (C), had a high dynamic friction coefficient, and neither was suitable for the present invention.

Claims

1. An infrared-cutting film comprising an infrared-absorbing layer laminated on a transparent substrate, the infrared-absorbing layer being a cured product of a resin composition comprising: an infrared-absorbing component (A); an acrylic compound (B) which is free of fluorine and silicone; an acrylic compound (C) which is free of fluorine and contains silicone; and a photopolymerization initiator (D).

2. 2. The infrared ray blocking film according to claim 1, wherein the retardation value of the transparent substrate is 100 nm or less.

3. 3. The infrared ray blocking film according to claim 1, wherein the component (C) is an acrylic (meth)acrylate having an acrylic main chain and a silicone side chain.

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