Antiviral and anti-fingerprint hard coat resin composition and laminate using same

Abstract

To provide a photocurable hard coat resin composition that has high transparency and steel wool resistance and also has excellent anti-fingerprint and anti-viral properties, and a laminate having a cured layer thereof.SOLUTION: A hard coat resin composition contains an acrylic binder, a monovalent copper compound, a surface-conditioning agent, and a photopolymerization initiator. The acrylic binder contains a methacrylate having three or more functional groups, including a hydroxy group. The content of the monovalent copper compound is 2-23 pts.wt. relative to 100 pts.wt. of the acrylic binder.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photocurable hard coat resin composition having excellent anti-fingerprint properties and high anti-viral properties, and a laminate having a cured layer thereof. [Background technology]

[0002] Acrylic photocurable resins are used in many fields to impart special properties to the surfaces of plastic films and plastic moldings. For example, hard-coated films, which are applied to PET (polyethylene terephthalate) films to impart high hardness, are used in large quantities as films for touch panels and molding films.

[0003] In particular, hard coat films are widely used as surface components for touch panels, which are input devices for information terminals, and are also often attached via an adhesive layer to the outermost surface of portable mobile devices such as smartphones and game consoles to prevent scratches. Because such hard coat films are used in areas that are directly touched by operators, they are prone to being stained with sebum and fingerprints, which can cause problems such as making it difficult to see the image layer or deteriorating the appearance.

[0004] To address these issues, a film with a hard coat layer containing a polymerizable compound, a hydrophobic multifunctional polymer resin, and spherical silica particles has been proposed as a hard coat film with high transparency and anti-fingerprint properties (Patent Document 1). While the use of such technology has improved anti-fingerprint properties, the recent spread of infectious diseases, exemplified by COVID-19, has led to increased demand for anti-viral functionality. While this anti-viral functionality can be achieved by adding an anti-viral agent, the manifestation of anti-viral properties varies greatly depending on the combination of binder, compounding conditions, and manufacturing process. Therefore, there was room for improvement in creating a hard coat resin that could achieve both anti-fingerprint properties and anti-viral properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-85638 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a photocurable hard coat resin composition that has high transparency and steel wool resistance as well as excellent anti-fingerprint and anti-viral properties, and a laminate having a cured layer thereof. [Means for solving the problem]

[0007] In order to solve the above problems, the invention of claim 1 provides a composition comprising an acrylic binder (A), a monovalent copper compound (B), a surface conditioner (C), and a photopolymerization initiator (D), wherein (A) contains a tri- or higher functional (meth)acrylate (a1) having a hydroxyl group, and the amount of (B) blended per 100 parts by weight of (A) is 2 to 23 parts by weight. and (C) is a silicone-based fluorine compound having a reactive functional group. The present invention provides a hard coat resin composition characterized by:

[0008] The invention of claim 2 is The contact angle of the cured film is 100° to 115°, measured according to the sessile drop method of JIS R 3257:1999. The hard coat resin composition according to claim 1, wherein the hard coat resin composition is

[0009] The invention of claim 3 provides the hard coat resin composition of either claim 1 or 2, characterized in that the blending amount of (C) is 0.03 to 1.0 wt % based on the total amount of solids.

[0010] The invention of claim 4 provides a laminate having a cured layer of the hard coat resin composition of any one of claims 1 to 3 on a substrate. [Effects of the Invention]

[0011] The hard coat (hereinafter referred to as HC) resin composition of the present invention has high transparency and steel wool resistance (hereinafter referred to as SW resistance), as well as excellent anti-fingerprint properties and high anti-viral properties, and is therefore useful as a coating agent to be applied to laminates such as HC films. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below.

[0013] The composition of the present invention comprises an acrylic binder (A), a monovalent copper compound (B), a surface conditioner (C), and a photopolymerization initiator (D). In this specification, the term "(meth)acrylate" includes both acrylate and methacrylate.

[0014] The acrylic binder (A) used in the present invention is the main component that forms the HC layer and contains a tri- or higher functional (meth)acrylate (a1) having hydroxyl groups. The presence of hydroxyl groups improves the hydrophilicity of the coating surface, facilitating the antiviral properties of the monovalent copper compound (B). The tri- or higher functionality increases the crosslinkability of the cured coating, improving SW resistance.

[0015] Examples of (a1) include pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, diglycerin tri(meth)acrylate, and alkylene oxide adducts thereof, which can be used alone or in combination of two or more. Among these, pentaerythritol triacrylate (hereinafter referred to as PETA) is preferred because it has little shrinkage after curing and causes little curling of the laminate.

[0016] Examples of acrylic binders (A) other than (a1) include (meth)acrylates having difunctional or less hydroxyl groups, such as 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, and pentaerythritol di(meth)acrylate; difunctional (meth)acrylates, such as (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 4,6-hexanediol di(meth)acrylate; and trifunctional or higher functional (meth)acrylates, such as trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, diglycerin tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. In addition to the above, monofunctional (meth)acrylates may also be included.

[0017] The ratio of (a1) in (A) is preferably 50% by weight or more, more preferably 70% by weight or more. The blending ratio of (a1) to the total solid content is preferably 40% by weight or more, more preferably 60% by weight or more, and particularly preferably 70% by weight or more. By ensuring these ratios or more, it is possible to ensure good properties with a good balance between antiviral properties and SW resistance.

[0018] The monovalent copper compound (B) used in the present invention serves as an antiviral agent. Metallic materials with antiviral properties generally include compounds containing copper, silver, titanium, tin, iron, nickel, zinc, etc. Among these, monovalent copper in particular does not require the addition of stabilizers, allowing for greater freedom in the design of its constituent components and boasting high antiviral properties. Examples of monovalent copper compounds with antiviral properties include chlorides, iodides, bromides, oxides, and thiocyanides.

[0019] The mechanism of the antiviral properties of (B) above is thought to be that when a monovalent copper compound comes into contact with viruses or bacteria, monovalent copper ions are generated, and these monovalent copper ions react with oxygen to generate active oxygen, which then kills the viruses or bacteria together with the copper ions. However, the applicant has discovered that by dispersing this monovalent copper compound in a tri- or higher functional binder with hydroxyl groups and adjusting the blending amount within a specific range, it is possible to achieve stable and excellent antiviral properties. Although the reason for this is not entirely clear, it is thought that the inclusion of a specific amount of a highly hydrophilic binder makes it easier for moisture in the air to be adsorbed, creating an environment that is more conducive to the generation of monovalent copper ions when the monovalent copper compound comes into contact with viruses or bacteria.

[0020] The amount of (B) to be blended relative to 100 parts by weight of (A) is 2 to 23 parts by weight, preferably 3 to 22 parts by weight, and more preferably 4 to 21 parts by weight. If it is 2 parts by weight or less, sufficient antiviral properties cannot be ensured, and if it is 23 parts by weight or more, SW resistance decreases and high transparency cannot be ensured.

[0021] The surface conditioner (C) used in the present invention is blended to improve the slip properties of the HC layer to improve SW resistance, and to increase water repellency and anti-fingerprint properties. Examples include silicone-based, fluorine-based, and acrylic-based compounds. Preferably, the compound has a reactive functional group capable of polymerizing with the binder resin to form a cured coating film, since the effect can be maintained for a long period of time without bleeding or other bleed-out effects from the cured coating. Silicone-based fluorine compounds are particularly preferred because their low surface free energy allows them to easily segregate on the coating surface after coating and drying, thereby stabilizing SW resistance and anti-fingerprint properties over a long period of time.

[0022] The blending amount of (C) relative to the total solid content is preferably 0.03 to 1.0 parts by weight, more preferably 0.05 to 0.3% by weight, and particularly preferably 0.06 to 0.1% by weight. By adding 0.03% by weight or more, it is expected that SW resistance and anti-fingerprint properties will be improved, and by adding 1.0% by weight or less, sufficient antiviral properties will be ensured. An example of a commercially available product is X-71-1203M (trade name: manufactured by Shin-Etsu Chemical Co., Ltd., solid content 20%, silicone-based fluorine compound having reactive functional groups).

[0023] The photopolymerization initiator (D) used in the present invention generates radicals upon irradiation with ultraviolet light or an electron beam, and these radicals trigger the polymerization reaction, and general-purpose photopolymerization initiators such as benzyl ketals, acetophenones, and phosphine oxides 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, and acylphosphine oxides include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and these can be used alone or in combination of two or more.

[0024] Among these, it is preferable to use an α-hydroxyacetophenone-based resin that is resistant to yellowing, and examples of commercially available products include Omnirad 127, Omnirad 184, and Omnirad 2959 (trade names: manufactured by IGM Resins). The amount of (D) added per 100 parts by weight of component (A) is preferably 2 to 10 parts by weight, more preferably 3 to 8 parts by weight.

[0025] The resin composition of the present invention may contain additives such as antioxidants, ultraviolet absorbers, sensitizers, flame retardants, fillers, organic fine particles, inorganic fine particles, dispersants, silane coupling agents, leveling agents, antifoaming agents, antistatic agents, polymerization inhibitors, colorants such as pigments, dyes and coloring matters, and plasticizers, as needed, within the range that does not impair performance.

[0026] When the resin composition of the present invention is applied to a plastic substrate, it may be diluted with a solvent such as toluene, isobutanol, ethyl acetate, butyl acetate, hexane, cyclohexane, cyclohexanone, methylcyclohexanone, acetone, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether (hereinafter referred to as PGM) to improve coating properties. The solid content when diluted is, for example, 20 to 50%, but is not particularly specified and can be appropriately set to obtain a viscosity that is easy to apply.

[0027] Examples of substrates onto which the resin composition of the present invention is applied include PET film, triacetyl cellulose film, polycarbonate film, polysulfone film, nylon film, cycloolefin film, acrylic film, polyimide film, ABS film, polyolefin film, PVC film, and PVA film. Among these, PET film is preferred because of its wide range of options and high versatility. The film thickness may be approximately 25 μm to 500 μm.

[0028] The substrate film to which the resin composition of the present invention is applied can be subjected to surface treatments such as primer treatment, corona treatment, surface roughening treatments such as sandblasting and solvent treatment, and surface oxidation treatments such as chromic acid treatment and ozone / ultraviolet irradiation treatment, in order to improve adhesion.

[0029] The resin composition of the present invention can be applied to a substrate film by known methods 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 thickness is typically 1 to 20 μm as a dry film thickness, but is not particularly specified and can be selected as needed.

[0030] After coating the resin composition of the present invention, it is dried at 60 to 120°C to volatilize the solvent, and then cured using an ultraviolet irradiator. 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 as the light source. The ultraviolet irradiation conditions are 500 mW / cm. 2 ~3,000mW / cm 2 The irradiation intensity is 100mJ / cm 2 ~2,000mJ / cm 2 Examples include:

[0031] The water contact angle of a laminate having a cured layer of the HC resin composition of the present invention is preferably 100° to 115°, and more preferably 103° to 110°. By setting the water contact angle to 100° or more, sufficient anti-fingerprint properties can be ensured, and by setting the water contact angle to 115° or less, anti-viral properties can be stably activated. In this specification, the water contact angle is a value measured based on the sessile drop method of JIS R 3257:1999.

[0032] Viruses are broadly classified into those enveloped in a lipid-containing membrane called an envelope and those without an envelope. Enveloped viruses are composed mostly of lipids and can be easily destroyed with disinfectants such as ethanol or soap, whereas non-enveloped viruses are generally considered to be highly resistant to disinfectants. The resin composition of the present invention has excellent antiviral properties against both types of viruses.

[0033] The present invention will be described in detail below based on examples and comparative examples, but these are intended to be specific examples and are not intended to limit the scope of the invention. Unless otherwise specified, measurements were carried out at a room temperature of 25°C and a relative humidity of 65%. The blend amounts are in parts by weight.

[0034] Examples 1 to 3 PETA was used as (A), a monovalent copper compound was used as (B), X-71-1203M (trade name: manufactured by Shin-Etsu Chemical Co., Ltd., solid content 20%, silicone-based fluorine compound having a reactive functional group) was used as (C), and Omnirad184 (trade name: manufactured by IGM Resins) was used as (D), and these were blended so that the solid content ratio was the ratio shown in Table 1, and then diluted with PGM so that the solid content was 40%, and stirred until uniformly dissolved and dispersed, thereby preparing the HC resin compositions of Examples 1 to 3.

[0035] Comparative Examples 1 to 8 In addition to the materials used in the examples, 9EG-A (trade name: manufactured by Kyoeisha Chemical Co., Ltd., bifunctional OH group-free), 701A (trade name: manufactured by Shin-Nakamura Chemical Co., Ltd., 2-hydroxy-3-methacrylpropyl acrylate, bifunctional OH group-free), TMPTA (trimethylolpropane triacrylate, trifunctional OH group-free), DPHA (dipentaerythritol hexaacrylate, hexafunctional OH group-free), and RUA076MG (trade name: manufactured by Asia Kogyo Co., Ltd., hexafunctional urethane acrylate, OH group-free) were used as binders, and these were mixed to obtain the solid content ratios shown in Table 1, and further diluted with PGM to make the solid content 40%, and stirred until uniformly dissolved and dispersed, thereby preparing the HC resin compositions of Comparative Examples 1 to 8.

[0036] Table 1 JPEG0007734506000001.jpg55135

[0037] Preparation of evaluation film The compositions of the examples and comparative examples prepared above were applied to U403 (product name: polyester film, 100 μm thick, manufactured by Toray Industries, Inc.) so that the dry film thickness would be 4 μm. The coating was then dried in a thermostatic chamber at 80°C for 1 minute, and then irradiated with ultraviolet light from a high-pressure mercury lamp at an output of 1300 mW / cm2 and an accumulated light amount of 100 mJ to prepare a film for evaluation.

[0038] The evaluation method was as follows.

[0039] Antiviral activity value: According to the antiviral test measurement method for photocatalytic materials in JIS R 1756:2013, bacteriophage Qβ was used as the test virus and the viral infectivity value after 6 hours was measured. The difference in the viral infectivity value with the blank film was used as the antiviral activity value, with over 4.0 being rated as ◎, 4.0 to 2.0 being ◯, and less than 2.0 being ×.

[0040] Transparency (haze): Measured in accordance with JIS K7361-1 using Haze-GARD2 manufactured by Toyo Seiki Seisakusho Co., Ltd., with less than 2% being rated as ⊚, 2 to 2.5% being ◯, and more than 2.5% being x.

[0041] Steel wool resistance: A load of 1,000 g / cm2 was placed on steel wool #0000 and moved back and forth 10 times. When visually inspected, if no scratches were found, the test piece was rated as ◎, if there were 1 to 20 scratches, it was rated as 〇, and if there were 20 or more scratches, it was rated as ×.

[0042] Water contact angle: According to the sessile drop method of JIS R 3257:1999, water was dropped at room temperature using a DMs-400 manufactured by Kyowa Interface Science Co., Ltd., and the contact angle was measured after leaving it to stand for 30 seconds. A value of 100° to 115° was marked as ◯, and values ​​outside this range were marked as ×.

[0043] Evaluation results Table 2 JPEG0007734506000002.jpg46135

[0044] Each of the compositions of the Examples obtained good results in the evaluations of antiviral activity value, transparency, SW resistance, and water contact angle.

[0045] On the other hand, Comparative Example 1, in which (B) was below the lower limit, had a low antiviral activity value, and Comparative Example 2, in which (B) was above the upper limit, had poor transparency and SW resistance. Furthermore, Comparative Example 3, which did not contain (C), had a low water contact angle, Comparative Examples 4 and 5, which used a difunctional (meth)acrylate, had poor SW resistance, Comparative Example 6, which used a trifunctional (meth)acrylate without OH groups, had poor antiviral activity value and SW resistance, and Comparative Examples 7 and 8, which used a hexafunctional (meth)acrylate without OH groups, had low antiviral activity values, and none of these were suitable for the present invention.

Claims

1. 1. A hard coat resin composition comprising: an acrylic binder (A), a monovalent copper compound (B), a surface conditioner (C), and a photopolymerization initiator (D), wherein (A) contains a tri- or higher functional (meth)acrylate (a1) having a hydroxyl group; the blending amount of (B) is 2 to 23 parts by weight per 100 parts by weight of (A); and (C) is a silicone-based fluorine compound having a reactive functional group.

2. The hard coat resin composition according to claim 1, wherein the contact angle of the cured film is 100° to 115° as measured by a method conforming to the sessile drop method of JIS R 3257:1999.

3. 3. The hard coat resin composition according to claim 1, wherein the amount of (C) is 0.03 to 1.0% by weight based on the total solid content.

4. A laminate having a cured layer of the hard coat resin composition according to any one of claims 1 to 3 on a substrate.

Images