KR102326487B1 - A Coating Composition and A Hard Coating Film Using The Same - Google Patents

Abstract

An object of the present invention is to provide a coating composition for a hard coat film and a hard coat film having good weather resistance while maintaining excellent scratch resistance and adhesion to a substrate. In addition, the present invention provides a coating composition for a hard coating film and a hard coating film having excellent adhesion to a substrate even after storage in a high-temperature and high-humidity environment.
As the solution, (A) an energy ray-curable (meth)acrylate monomer having a weight average molecular weight of 250 or more and 1000 or less, the number of energy ray-curable functional groups is 2 or more and 9 or less, and the number of hydroxyl groups is 1 or less, (B) an energy ray-curable functional group A hard coat film is prepared from the coating composition containing the ultraviolet absorber and (C) the weight average molecular weight of 1500 or more and the energy-beam curable oligomer of 20000 or less.

Description

A Coating Composition and A Hard Coating Film Using The Same

The present invention relates to a coating composition and a hard coat film using the same.

Conventionally, in order to prevent scratches on the surface of glass or resin molded body, a hard coating film having a hard coating film or a hard coating layer on a resin film by applying a coating paint made of an energy ray-curable resin or the like to the surface is described above. It is used by sticking to glass or a resin molded body.

The above hard coating film and hard coating film are widely used for applications such as displays, touch panels, and display screens of mobile phones. As such a hard coating film for outdoor use, it is required that it does not yellow even when exposed to ultraviolet rays for a long time. For this reason, for the purpose of imparting weather resistance, it has been proposed to add an ultraviolet absorber or a light stabilizer to the hard coat layer (Patent Document 1).

Japanese Patent Laid-Open No. 9-157315

However, in the hard coat film proposed in Patent Document 1, the addition of an ultraviolet absorber or a light stabilizer causes curing inhibition and a problem in that the coating film hardness, scratch resistance, and adhesion to the substrate are lowered. This problem is remarkable when a large amount of an ultraviolet absorber or a light stabilizer is added in order to cope with a higher level of weather resistance.

In addition, in order to suppress the production cost of the mobile product, the production base of each component and the assembly base of the mobile product are often different from each other. In consideration of preservation, the hard coating layer should not deteriorate (scratch resistance) under a high temperature and high humidity environment. In addition, it is necessary to have excellent adhesion to the substrate that does not cause peeling between the hard coating layer and the transparent support even in such an environment.

Accordingly, it is an object of the present invention to provide a coating composition for a hard coat film and a hard coat film having good weather resistance while improving the above drawbacks and maintaining excellent scratch resistance and adhesion to a substrate. Another object of the present invention is to provide a coating composition for a hard coat film and a hard coat film having excellent adhesion to a substrate even after storage in a high temperature and high humidity environment.

The present inventors have conducted intensive studies to solve the above problems, and as a result, an energy ray-curable (type) (meth)acrylate monomer having a specific molecular weight, a specific number of energy ray-curable functional groups, and a number of hydroxyl groups, energy having a specific molecular weight By using a coating composition containing a precurable (meth)acrylate oligomer and a specific ultraviolet absorber, it found out that the said subject could be solved, and came to complete this invention.

In addition, (meth)acrylate refers to an acrylate or a methacrylate.

That is, according to this invention, the coating composition and hard-coat film of the structure shown below are provided.

The coating composition of the present invention is (A) an energy ray-curable (meth)acrylate monomer having a weight average molecular weight of 250 or more and 1000 or less, the number of energy ray-curable functional groups is 2 or more and 9 or less, and the number of hydroxyl groups is 1 or less, (B) energy ray It is characterized by containing a sclerosing|hardenable functional group containing ultraviolet absorber and (C) weight average molecular weights 1500 or more and 20000 or less energy-beam curable oligomer.

The coating composition of the present invention comprises (E1) a photopolymerization initiator having a maximum absorbance value of 0.1 or more in a wavelength range of 340 nm to 400 nm of a 0.01 mass % methanol solution or acetonitrile solution, and (E2) 0.001 mass % methanol It is preferable that the solution further contains a photopolymerization initiator whose maximum value of absorbance in the wavelength range of 220 nm to 280 nm is 0.1 or more.

Moreover, as for the coating composition of this invention, it is preferable that mass ratio ((A) component: (C)component) of (A) component and (C)component is 3:97-50:50.

Moreover, in the coating composition of this invention, it is preferable that the maximum value of the absorbance in the wavelength range of 280 nm - 370 nm of 0.0619 mmol/l dichloromethane solution of component (B) is 0.6 or more of ultraviolet absorbers.

The hard coat film of the present invention is characterized in that it has a hard coat layer obtained from the coating composition on at least one surface of a transparent support.

In the hard coat film of the present invention, the thickness of the hard coat layer is preferably 0.5 µm or more and 20 µm or less.

Further, in the hard coat film of the present invention, it is preferable that the adhesion between the hard coat layer and the transparent support is 90/100 or more based on JIS K5400.

In addition, the hard coat film of the present invention has a substrate adhesion between the hard coat layer and the transparent support after the moisture resistance test left for 550 hours in an environment of a temperature of 60° C. and a relative humidity of 90% RH is 90/100 or more based on JIS K5400 it is preferable

In addition, it is preferable that the hard coating film of the present invention has a degree of yellowing (Δb) of less than 1 after 12 cycles of the weather resistance test specified in ASTM G-154.

According to the present invention, it is possible to provide a coating composition for a hard coat film and a hard coat film having excellent scratch resistance, weather resistance and adhesion to a substrate.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention is described in detail.

(1) coating composition

The coating composition of the present invention is (A) an energy ray-curable (meth)acrylate monomer having a weight average molecular weight of 250 or more and 1000 or less, the number of energy ray-curable functional groups is 2 or more and 9 or less, and the number of hydroxyl groups is 1 or less, (B) energy ray It is characterized by containing a sclerosing|hardenable functional group containing ultraviolet absorber and (C) weight average molecular weights 1500 or more and 20000 or less energy-beam curable oligomer.

Each component is demonstrated below.

(A) Energy-ray-curable (meth)acrylate monomer

In the coating composition of the present invention, it is essential to use an energy ray-curable (meth)acrylate monomer having a weight average molecular weight of 250 or more and 1000 or less, the number of energy ray-curable functional groups is 2 or more and 9 or less, and the number of hydroxyl groups is 1 or less. By using such a monomer, hardness, scratch resistance, and adhesion to a substrate can be improved. In particular, it is possible to effectively improve the adhesion to the substrate in a high-temperature and high-humidity environment.

By setting the weight average molecular weight of the (meth)acrylate monomer to 250 or more, it is possible to impart film properties when the hard coating layer is formed. For this reason, while base material adhesiveness improves, the fall of scratch resistance can be suppressed. In addition, in the manufacturing process of the hard coating layer, volatilization of unreacted monomers due to heating can be prevented. On the other hand, by making a weight average molecular weight into 1000 or less, molecular weight is not too large, and (A) component becomes easy to arrange|position in the space|interval of (B) component and (C)component molecule|numerator so that it may mention later. Therefore, while crosslinking efficiency improves and base material adhesiveness improves, the fall of the scratch resistance by addition of a ultraviolet absorber can be suppressed. Moreover, when it is set as the coating liquid for hard-coat layers, it can prevent from becoming high in viscosity. In addition, the weight average molecular weight of a (meth)acrylate monomer can be confirmed with a gel permeation chromatography (GPC).

By making the number of hydroxyl groups of a (meth)acrylate monomer into 1 or less, the fall of the base-material adhesiveness in a high-temperature, high-humidity environment can be suppressed. In this invention, in order to use the energy-beam curable monomer with a weight average molecular weight of 250 or more and 1000 or less as mentioned above, even if it does not have a hydroxyl group, sufficient base-material adhesiveness is acquired. When the (meth)acrylate monomer has one hydroxyl group, the above-described transparent support, that is, since adhesiveness is improved by the reaction of the acidic functional group present on the surface of the glass or resin substrate with the hydroxyl group, adhesion to the substrate can be further improved.

When a monomer having two or more hydroxyl groups is used, it is advantageous in that adhesiveness is improved by reaction with a functional group on the surface of the transparent support. However, since unreacted hydroxyl groups remain in the hard coating layer, the adhesiveness of the substrate is lowered under the influence of the remaining hydroxyl groups under a high-temperature and high-humidity environment. In the present invention, since the number of hydroxyl groups in the (meth)acrylate monomer is set to 1 or less, unreacted hydroxyl groups hardly exist after the curing reaction, and the decrease in adhesion to the substrate due to residual hydroxyl groups even in a high-temperature and high-humidity environment can suppress.

Further, when the number of energy ray-curable functional groups of the (meth)acrylate monomer is 2 or more and 9 or less, a hard coat film having high hardness and excellent scratch resistance and substrate adhesion can be obtained. By setting the number of energy ray-curable functional groups to a (meth)acrylate monomer of 2 or more, the crosslinking reaction with (B) component and (C) component proceeds more effectively, so that adhesion to the substrate is improved and at the same time, due to the addition of the ultraviolet absorber A decrease in scratch resistance can be suppressed. When the number of energy ray-curable functional groups of the (meth)acrylate monomer is 1 or less, it is difficult to obtain a hard coating film having high hardness and excellent scratch resistance. In addition, when such a (meth)acrylate monomer is used, since the crosslinking reaction does not proceed sufficiently, the obtained hard coat film is easily deteriorated by ultraviolet light, and it is difficult to obtain excellent weather resistance. Moreover, since crosslinking reaction does not fully advance, it is also difficult to obtain the outstanding board|substrate adhesiveness.

On the other hand, when a (meth)acrylate monomer having a number of energy ray-curable functional groups of 9 or less is used, the component (A) is easily disposed in the gap between the molecules of the component (B) and the component (C), and the crosslinking efficiency is also improved. Adhesiveness improves and the fall of the scratch resistance by addition of a ultraviolet absorber can be suppressed. When a (meth)acrylate monomer in which the number of energy ray-curable functional groups exceeds 9 is used, an excessive crosslinking reaction between (A) components tends to proceed, so that (A) component (B) component and (C) component molecules Since it is difficult to be disposed in the gap and the crosslinking density is difficult to increase, it is difficult to obtain a hard coat film having excellent scratch resistance and adhesion to the substrate.

As the above (A) (meth)acrylate monomer, dipentaerythritol hexa(meth)acrylate, trimethylolpropane (meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate , triethylene glycol divinyl ether, tetraethylene glycol (meth) acrylate, tripropylene glycol (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate , neopentyl glycol di (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, dipentaerythritol polyacrylate, di Pentaerythritol hexaacrylate, tricyclodecane dimethanol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylol propane triacrylate, and ditrimethylol propane tetraacrylate are mentioned. Among these, dipentaerythritol hexaacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate are preferable from the viewpoint of good adhesion to a transparent support and high reactivity.

(B) UV absorber

The coating composition of this invention contains an energy-ray-curable functional group containing ultraviolet absorber. Usually, in order to obtain the weather resistance of the hard coat layer and the hard coat film, a UV absorber is added to the coating composition. In the present invention, since the ultraviolet absorber contains an energy ray-curable functional group-containing ultraviolet absorber, the crosslinking reaction between the above-mentioned (A) component and the later-mentioned (C) component proceeds effectively, so that the crosslinking density is improved, The fall of the scratch resistance by addition of a ultraviolet absorber can be suppressed. In addition, since the ultraviolet absorber is introduced into the crosslinked structure by the crosslinking reaction, bleed out from the hard coating layer is suppressed, thereby suppressing a decrease in adhesion to the substrate. Especially in a high temperature and high humidity environment, when the coating composition of this invention using the ultraviolet absorber which has an energy ray-curable functional group is used, the fall suppression effect of base material adhesiveness is recognized remarkably.

As such an energy ray-curable functional group-containing ultraviolet absorber, a benzotriazole-based and triazine-based ultraviolet absorber can be used. Examples of the benzotriazole-based ultraviolet absorber (compound) include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-butylphenyl)benzo Triazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3', 5'-di-t -Butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-(2-(octyloxycarbonyl)ethyl)phenyl)-5-chlorobenzotria Sol, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3', 5'-di-t-amyl Phenyl) benzotriazole, 2-(2'-hydroxyl-5'-t-octylphenyl)benzotriazole, 2-(2'-hydroxyl-3', 5'-di(dimethylbenzyl)phenyl)benzo Triazole, 2-(2'-hydroxyl-4'-octyloxyphenyl)benzotriazole, 2,2'-methylenebis(2-(2'-hydroxyl-5'-t-octylphenyl)benzotriazole Sol) 2-(2'-hydroxy-3'-(3,4,5,6-tetrahydrophthalimidylmethyl)-5'-methylbenzyl)phenyl)benzotriazole, etc. (meth)acryloyl group The compound which has can be mentioned. Further, as the triazine-based ultraviolet absorber (compound), 2-(4-hexyloxy-2-hydroxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(4-octyloxy -2-hydroxyphenyl)-4,6-di(2,5-dimethylphenyl)-1,3,5-triazine, 2-(4-butoxy-2-hydroxyphenyl)-4,6- di(4-butoxyphenyl)-1,3,5-triazine, 2-(4-butoxy-2-hydroxyphenyl)-4,6-di(2,4-dibutoxyphenyl)-1, 3,5-triazine, 2-(4-(3-(2-ethylhexyloxy)-2-hydroxypropoxy)-2-hydroxyphenyl)-4,6-di(2,4-dimethyl Phenyl)-1,3,5-triazine, 2-(4-(3-dodecyloxy-2-hydroxypropoxy)-2-hydroxyphenyl)-4,6-di(2,4-dimethyl Phenyl)-1,3,5-triazine, 2,4-di(4-butoxy-2-hydroxyphenyl)-6-(4-butoxyphenyl)-1,3,5-triazine, 2 , 4-di(4-butoxy-2-hydroxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3,5-triazine, etc., and a compound having a (meth)acryloyl group. have. Among them, an ultraviolet absorber having a maximum absorbance of 0.6 or more in the wavelength range of 280 nm to 370 nm of a 0.0619 mmol/l solution dissolved in dichloromethane is preferable from the viewpoint of excellent ultraviolet absorption performance. Examples of the ultraviolet absorber include a compound having 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and a (meth)acryloyl group, and 2-(4-hexyloxy-2-hydroxyphenyl)- A compound having 4,6-diphenyl-1,3,5-triazine and a (meth)acryloyl group is preferably used. The above energy-ray-curable functional group containing ultraviolet absorbers may be used individually by 1 type, and may use 2 or more types together.

The amount of component (B) to be added also varies depending on the desired weather resistance performance and the thickness of the hard coat layer, but as a lower limit, 2 parts by mass or more, with respect to 100 parts by mass in total of the above-described component (A) and component (C) to be described later, add The furnace is preferably 2.5 parts by mass or more, and more preferably 3 parts by mass or more. Moreover, as an upper limit, it is 12 mass parts or less, Furthermore, it is 10 mass parts or less, Furthermore, it is preferable to set it as 8 mass parts or less. By setting the lower limit to 2 parts by mass or more, more excellent weather resistance can be obtained, and by setting the upper limit to 12 parts by mass or less, excellent coating film hardness, scratch resistance, and adhesion to the substrate can be maintained.

(C) (meth)acrylate oligomer (energy-ray-curable oligomer)

The coating composition of this invention contains the energy-beam curable oligomer whose weight average molecular weights are 1500 or more and 20000 or less. From the coating composition containing the oligomer, a hard coat layer and hard coat film having good coating film hardness and scratch resistance can be obtained.

When the weight average molecular weight of the energy ray-curable oligomer is 1500 or more, a hard coat film and a hard coat film having good flexibility and adhesion to a substrate can be obtained. Further, when the weight average molecular weight of the energy ray-curable oligomer is 20000 or less, preferably 10000 or less, a hard coat film or hard coat film having good coating film hardness and scratch resistance can be obtained.

Moreover, it is preferable here that the weight average molecular weight of an energy-beam curable oligomer is 1.5 to 20 times the weight average molecular weight of an energy-beam curable monomer ((meth)acrylate monomer). By setting the ratio of the weight average molecular weight of the energy ray-curable oligomer to the weight average molecular weight of the energy ray-curable monomer within the above range, the energy ray-curable monomer easily enters the gap between the energy ray-curable oligomer, so that the crosslinking reaction proceeds in a denser state. As a result, the crosslinking density increases, whereby the decrease in hardness and scratch resistance due to the addition of the ultraviolet absorber can be effectively suppressed. In addition, here, the weight average molecular weight of an energy-beam curable monomer and an energy-beam curable oligomer is a value calculated|required from a gel permeation chromatography (GPC).

As the energy ray-curable oligomer, a (meth)acrylic oligomer having two or more (meth)acryloyl groups in one molecule and forming a three-dimensional network structure by crosslinking and curing is particularly preferably used. Examples of the (meth)acrylic oligomer include urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl acrylate, and silicone acrylate. can

It is preferable that the energy ray-curable oligomer is a polyfunctional urethane (meth)acrylate oligomer whose number of energy ray-curable functional groups is 10 or more and 20 or less. By using such a polyfunctional urethane (meth)acrylate oligomer, since a high crosslinking density can be achieved, coating-film hardness and scratch resistance can be improved more. By setting the number of energy ray-curable functional groups of the polyfunctional urethane (meth)acrylate oligomer to 10 or more, the crosslinking density can be sufficiently increased to increase the hardness. And as a result, scratch resistance can be improved significantly. In addition, by setting the number of energy ray-curable functional groups to 20 or less, preferably 16 or less, steric hindrance due to high crosslinking density can be suppressed, and a decrease in hardness due to curing inhibition can be prevented.

The content ratio of component (A) (energy-ray-curable monomer) and component (C) (energy-ray-curable oligomer) in the coating composition of the present invention is preferably 3:97 to 50:50 by mass, and further The ratio is preferably 5:95 to 30:70. By making the mass ratio of component (A) and component (C) in the coating composition within the above range, the adhesion between the hard coating layer and the transparent support, particularly the adhesion to the substrate after the moisture resistance test, can be made more favorable.

(D) light stabilizer

It is preferable that the coating composition of this invention contains a hindered amine light stabilizer as (D) a light stabilizer. By adding a hindered amine light stabilizer to the hard coating layer, radicals generated by ultraviolet light can be efficiently supplemented, and thus weather resistance can be further improved. (D) As the light stabilizer, for example, 4-pezoyloxy-2,2,6,6-tetramethylpiperidine, 4-hexanoyloxy-2,2,6,6-tetramethylpiperidine , 4-octanoyloxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, succinic acid-bis(2,2, 6,6-tetramethylpiperidine), sebacic acid-bis(2,2,6,6-tetramethylpiperidine), sebacic acid-bis(1,2,2,6,6-pentamethyl-4 -piperidine), 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,4-dione, N- Methyl-3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidinyl)pyrrolidine-2,5-dione, N-acetyl-3-dodecyl-1-(2 ,2,6,6-tetramethyl-4-piperidinyl)pyrrolidine-2,5-dione, phthalic acid-bis(1,2,2,6,6-pentamethyl-4-piperidine), trimesic acid-tris(2,2,6,6-tetramethyl-4-piperidyl); and the like. These may be used individually by 1 type, and may use 2 or more types together.

(D) As for the addition amount of component, 0.05 mass part or more is preferable as a minimum with respect to a total of 100 mass parts of (A) component and (C)component mentioned above, Furthermore, 0.5 mass part or more is preferable, and 5 mass parts as an upper limit. Hereinafter, 3 parts by mass or less is further preferred. (D) When the addition amount of component shall be 0.05 mass part or more, favorable weather resistance is acquired, and favorable scratch resistance can be maintained by setting it as 5 mass parts or less.

(E) photopolymerization initiator

The (E) photopolymerization initiator used in the coating composition of the present invention includes (E1) a photopolymerization initiator having a maximum absorbance value of 0.1 or more in a wavelength range of 340 nm to 400 nm of a 0.01 mass% solution dissolved in methanol or acetonitrile; (E2) It is preferable to contain at least one photopolymerization initiator each having a maximum absorbance value of 0.1 or more in a wavelength range of 220 nm to 280 nm of a 0.001 mass% solution dissolved in methanol or acetonitrile. When forming a cured coating film by ultraviolet irradiation, the fall of the base material adhesiveness in a high temperature and high humidity environment can be suppressed largely by using these two types of photoinitiators compared with the case where it used individually, respectively.

[(E1) component]

The component (E1) used in the present invention is a photopolymerization initiator having a maximum absorbance value of 0.1 or more in a wavelength range of 340 nm to 400 nm of a 0.01 mass% solution dissolved in methanol or acetonitrile. For example, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine Oxide, 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6- Difluoro-3-(1H-pyrrol-1-yl)-phenyl) titanium, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butanone, diphenyl ( 2,4,6-trimethylbenzoyl)phosphine oxide etc. are mentioned. The said component may be used individually by 1 type, and may use 2 or more types together.

(E1) A commercial item can be used for a component, For example, Irgacure 651, 907, 819, 369, 379, 1800, 784, Darocure 4265, Lucirin TPO (above, BASF company make) etc. are mentioned.

[(E2) component]

Component (E2) used in the present invention is a photopolymerization initiator having a maximum absorbance value of 0.1 or more in a wavelength range of 220 nm to 280 nm of a 0.001 mass% solution dissolved in methanol or acetonitrile. For example, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one2,2-dimethoxy-1,2-diphenylethan-1-one, 1- [4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one , methyl oxophenyl acetate, and oligo[2-hydroxy-2-methyl-[1-(4-methylvinyl)phenyl]propanone. The said component may be used individually by 1 type, and may use 2 or more types together.

(E2) A commercial item can be used for component, for example, Irgacure 184, 651, 500, 2959, 127, 754, 907, 1800, Darocure 1173, MBF (above, BASF company make), Irgacure KIP150, KIP100F , ONE, (above, the Lamberti company make), etc. are mentioned.

It is preferable to make the addition amount of the photoinitiator which is the said (E1) component into a small amount rather than the addition amount of the photoinitiator which is the said (E2) component from a viewpoint of suppressing the fall of the base material adhesiveness in a high-temperature and high-humidity environment. Specifically, it is preferable that the addition ratio of (E1) component and (E2) component is the range of 3:97-45:55 by mass ratio. Moreover, when containing some (E1) component and/or (E2) component, it is preferable that ratio of each gross mass of (E1) component and (E2) component becomes the said range.

Moreover, as for a photoinitiator, it is one type, and there exists a thing which has the photoinitiation wavelength range of (E1) component and (E2) component. Hereinafter, the maximum value of the absorbance in the wavelength range of 340 nm to 400 nm of this photopolymerization initiator, that is, 0.01 mass % methanol solution or acetonitrile solution is 0.1 or more, and 220 nm to 0.001 mass % methanol solution The photoinitiator whose maximum value of absorbance in the wavelength range of 280 nm is 0.1 or more is called the (E1, 2) component or the photoinitiator of (E1, 2). However, even if it uses 1 type of the photoinitiator of (E1, 2), the same effect as when two types of the photoinitiator of (E1) and the photoinitiator of (E2) are used together cannot be acquired. On the other hand, when two or more types of the photoinitiator of (E1, 2) are used, the same effect as when the photoinitiator of (E1) and the photoinitiator of (E2) are used together is recognized. Moreover, even when the photoinitiator of (E1) or the photoinitiator of (E2) is further added to the photoinitiator of (E1, 2), the same effect is acquired. In this case, the more excellent effect is acquired by especially adding (E2) component. Moreover, it is preferable that the kind and quantity of the polymerization initiator which is an additive are as small as possible from the viewpoint of manufacture. However, as long as it does not affect the other physical properties of the hard coat layer or the hard coat film, the photopolymerization initiator of (E1) and the photoinitiator of (E2) may be added to the photoinitiator of (E1, 2).

In this application, in order to "contain (E1) component and (E2) component", the structure containing two or more types of the photoinitiator of (E1, 2), the photoinitiator of (E1, 2), and the photoinitiator of (E1) And/or the structure containing the photoinitiator of (E2) shall also be included.

By containing two types of photoinitiators as described above, the scratch resistance and adhesion to the substrate, which are problems of the hard coating film and the hard coating film obtained from the conventional energy ray-curable coating composition having ultraviolet absorption performance, can be improved. In particular, by using the said two types of photoinitiators, the coating film in which the adhesiveness of the base material in a high-temperature and high-humidity environment was improved significantly can be obtained.

The content of component (E) used in the hard coat paint of the present invention is preferably 1 part by mass, and further 3 parts by mass as the lower limit with respect to 100 parts by mass in total of the component (A) and component (C). and 15 parts by mass or less as an upper limit, and more preferably 12 parts by mass or less. By setting it as 1 mass part or more, coating-film hardness and base-material adhesiveness can be made sufficient, and by setting it as 15 mass parts or less, hardening inhibition by recombination of (E) components can be prevented, and base-material adhesiveness can be made sufficient.

In addition, in the coating composition of the present invention, if necessary, other resins and solvents, photopolymerization initiation aids, leveling agents, antifoaming agents, antioxidants, polymerization inhibitors, crosslinking agents, pigments, antifouling agents, fine particles, lubricants, optical brighteners, antistatic agents , flame retardants, antibacterial agents, fungicides, plasticizers, flow regulators, dispersants, mold release agents, and the like may be added to each to impart desired functions.

Examples of other resins include thermosetting resins, thermoplastic resins, bisphenol-based epoxy resins, novolak-type epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins such as epoxy resins, and photoionically polymerizable resins such as vinyl ether-based resins. etc. are mentioned, and it can make it contain in the range which does not impair the effect of this invention.

Examples of the solvent include aromatic solvents such as toluene and xylene; ester solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, and methoxypropyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, and diethylene glycol ethyl methyl ether : Other well-known organic solvents are mentioned.

The type of organic solvent to be used can be determined in consideration of solubility or dispersibility with the component (A), component (B), component (C), and the like added at the same time. An organic solvent having a boiling point of 120° C. or less, such as methyl ethyl ketone, methyl isobutyl ketone, or tetrahydrofuran, is preferable from the viewpoint that the solvent hardly remains in the hard coat layer after drying. The said organic solvent may be used individually by 1 type, and may use 2 or more types together. Although the amount of the solvent used is not particularly limited, it is preferable to adjust the composition viscosity to a viscosity suitable for the coating method employed. The preferred amount to be used is 5-90 mass% of the total composition, more preferably 10-85 mass%, and still more preferably 20-80 mass%.

As a photoinitiation adjuvant, an amine compound, a carboxylic acid compound, a polyfunctional thiol compound, etc. are mentioned, for example. Moreover, as a leveling agent, an acryl-type compound, a high boiling point solvent, a fluorine-type compound, a silicone type compound, etc. are mentioned. From the point of finishing the surface to a mirror surface, a fluorine-type compound and a silicone-type compound are preferable among the said leveling agents. As antioxidant, a phenol-type compound etc. are mentioned. As a polymerization inhibitor, metoquinone, methyl hydroquinone, hydroquinone, etc. are mentioned. As a crosslinking agent, isocyanate, a melamine compound, etc. are mentioned. Examples of the fine particles include inorganic fine particles such as silica and calcium carbonate, and organic fine particles such as polymethyl methacrylate and polystyrene. The antifouling agent includes a fluorine-based compound, a silicon-based compound, or a mixture thereof, and a fluorine-based compound is preferable in terms of antifouling performance.

In the coating composition of the present invention, the above-mentioned (A) component, (B) component, and (C) component, and, if necessary, other resins, solvents and additives such as light stabilizers and photoinitiators are added in any order, It can be obtained by mixing.

The coating composition of the present invention obtained in this way is a coating composition (hard coating paint) for coating and curing the surface of glass or a resin material. Since the hard coating paint of the present invention contains the above-mentioned component (A), component (B) and component (C), when using glass and resin materials as the material to be coated, the material to be coated and the cured coating film good adhesion. In particular, it can be set as a cured coating film excellent in adhesiveness (adhesion to a base material) between a to-be-coated object and a cured coating film in a high-temperature and high-humidity environment.

(2) hard coating film and hard coating film

The hard coating film of the present invention comprises the above-mentioned component (A), component (B) and component (C) and, if necessary, a coating composition (composition for hard coating layer) in which another resin or additive is dissolved or dispersed in a solvent. , it can be obtained by coating on at least one surface of a transparent support, drying if necessary, and curing by irradiation with energy rays or natural light. For application, a known method, for example, a gravure coating method, a bar coating method, a knife coating method, a roll coating method, a braid coating method, a die coating method, a spin coating method, a flow coating method, a dip coating method, a spray coating method, Screen printing method, brush application, etc. can be used. If the viscosity of the composition for hard coating layer is higher than the viscosity suitable for application, the viscosity may be adjusted using a solvent. Usable solvents are as described above.

As a transparent support body, things with high transparency, such as glass and a resin base material, can be used. Examples of the resin constituting the resin substrate include polyethylene terephthalate, polybutyrene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, polyvinyl chloride. , polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polystyrene, polycarbonate, polymethylpentene, polysulfone, polyetheretherketone, polyethersulfone, polyetherimide, polyimide, fluororesin, nylon, acryl, cycloolefin, norbornene compound etc. are mentioned. Among the above, the polyethylene terephthalate film which was stretched, particularly biaxially stretched, has excellent mechanical strength and dimensional stability, so it is suitably used.

For the purpose of improving adhesion to the hard coating layer, such a transparent support is subjected to surface roughening treatment by sandblasting or solvent treatment, or corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, plasma treatment, ozone/ultraviolet irradiation. You may perform surface treatment, such as a process, formation of an undercoat easily bonding layer, etc. In addition, the transparent support may be previously provided with a pressure-sensitive adhesive layer or printing or coating for imparting design on one or both surfaces before applying the composition for a hard coating layer. Moreover, as long as it is a range which does not impair the effect of this invention, the additive which can be used for the above-mentioned coating composition, such as an ultraviolet absorber and a light stabilizer, can be contained in a transparent support body.

The thickness of a transparent support body is not specifically limited, What is necessary is just to select suitably according to a use. In the case of glass, 0.3 mm to 5 mm are preferable, in the case of a resin base material, 25 micrometers - 500 micrometers are preferable, and 50 micrometers - 300 micrometers are more preferable.

When a solvent is included in the composition for hard coating layer, it is necessary to dry after application|coating. The drying temperature may be determined in consideration of the length of the drying line, the line speed, the application amount, the amount of residual solvent, the type of the transparent support, and the like. When the transparent support is a polyethylene terephthalate film, a general drying temperature is 50°C to 150°C, preferably 70°C to 130°C. When there are a plurality of dryers in one line, you may set each dryer to different temperature and wind speed. In order to obtain a coating film with a good coating appearance, it is preferable to make the drying conditions on the inlet side mild.

As a method of curing the composition for hard coating layer, as described above, it can be cured by irradiation with energy rays or natural light. In consideration of the stability of the physical properties of the hard coating layer and industrial workability, it is preferable to cure the hard coating layer by irradiation with energy rays. As an energy beam, an ultraviolet-ray, an electron beam, etc. are mentioned. In the case of curing by ultraviolet rays, an ultraviolet irradiation device having a xenon lamp, a high-pressure mercury lamp, a metal halide lamp, or the like is used as the light source, and the amount of light, arrangement of the light source, etc. are adjusted as necessary. When a high-pressure mercury lamp is used, curing is preferably performed at a conveying speed of 5 m/min to 60 m/min for lamp 1 having an energy of ^{80 W/cm 2} to 160 W/cm ^{2 .} In the case of curing with an electron beam, it is preferable to use an electron beam accelerator having an energy of 100 eV to 500 eV.

The thickness of the hard coating layer is not particularly limited and may be appropriately determined depending on the intended use, desired performance, handling, productivity, economic efficiency, and the like. When used for mobile products, the thickness is preferably 0.5 µm or more, further preferably 1 µm or more as the lower limit, and 20 µm or less, further 15 µm or less, and further preferably 10 µm or less as the upper limit. When the thickness of the hard coating layer is 0.5 µm or more, required coating film hardness, scratch resistance, weather resistance, and adhesion to the substrate can be obtained. When the thickness of the hard coat layer is 20 µm or less, it is possible to suppress a decrease in productivity and economic efficiency.

In the hard coat layer of the hard coat film of the present invention, the pencil hardness specified in JIS K5400 is preferably adjusted to 2H or more and 3H or more. In a coating film whose pencil hardness is adjusted to be equal to or higher than the above value, it is possible to effectively prevent the surface of the hard coat layer from being scratched.

In addition, the hard coating layer of the hard coating film of the present invention is made by covering steel wool of #0000 on a 3 cm ² columnar jig with a load of 500 g, and reciprocating at least 30 times, preferably reciprocating at least 50 times, It is preferable that it is adjusted so that damage may not occur when it reciprocates more preferably 70 times or more. By adjusting in this way, necessary scratch resistance can be ensured, and damage to the surface of the hard coating layer can be effectively prevented.

Further, in the hard coat film of the present invention, it is preferable that the adhesion between the hard coat layer and the transparent support is 90/100 or more according to JIS K5400. When base material adhesiveness is made into the said range, when used for a mobile product, a hard-coat layer can be used without peeling from a transparent support body.

In addition, the hard coat film of the present invention has a substrate adhesion according to JIS K5400 between the hard coat layer and the transparent support after a moisture resistance test left for 550 hours under an environment of a temperature of 60° C. and a relative humidity of 90% RH, 90/100 or more. it is preferable By setting the adhesion to the substrate after the moisture resistance test within the above range, it is possible to obtain a hard coating film in which adhesion between the hard coating layer and the transparent support is maintained even after the moisture resistance test. In addition, the hard coating film of the present invention can be used without deterioration in a high-temperature and high-humidity environment even in consideration of the transport environment and long-term storage of mobile products. In addition, it is preferable to have scratch resistance in the steel wool test as described above even after the moisture resistance test.

In addition, the hard coat film of the present invention preferably has a degree of yellowing (Δb) after 12 cycles of the weather resistance test specified in ASTM G-154 of less than 1.0, and further preferably less than 0.5. By setting the degree of yellowing (Δb) in the above range, even when used in mobile products used outdoors, it is difficult to yellow, and a hard coating film with low coating film deterioration can be made. In the present invention, the yellowing degree (Δb) represents a value obtained by subtracting the b value (b0) before the test from the b value (b1) after the weather resistance test. Therefore, it shows that the deterioration of a coating film is so low that this value is small.

As mentioned above, as one aspect of the hard coating film of this invention, having a hard coating layer on one side of a transparent support body was demonstrated. The present invention is not limited to the above configuration, and includes those having a hard coating layer on both sides of the transparent support, and those having a pressure-sensitive adhesive layer, a printed layer, and a vapor deposition layer on the side of the transparent support that does not have a hard coating layer. .

The hard coating film of the present invention as described above does not yellow because it has sufficient weather resistance even when used outdoors for display screens of mobile products such as mobile phones and smart phones. In addition, since it has excellent adhesion to the substrate, it can be used without causing peeling between the hard coating layer and the transparent support. In particular, the hard coat film of the present invention does not deteriorate the hard coat layer under a high temperature and high humidity environment, and thus has excellent adhesion to the substrate even in such an environment. For this reason, for example, even if it is a case where the production base of each component of a mobile product differs from the assembly base of a mobile product, it can use also in the environment of high temperature and high humidity at the time of manufacture and transportation of various component parts. In particular, in recent years, there is a tendency to add a large amount of ultraviolet absorbers and light stabilizers to the hard coating layer in order to cope with a higher level of weather resistance, which causes various problems. is useful

Example

Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples.

<Components of the coating composition>

The detail of each structural component used for the following Example and a comparative example is shown below.

(A) (meth)acrylate monomer (energy-ray-curable monomer)

A1: dipentaerythritol hexaacrylate monomer (trade name: light acrylate DPE-6 A, manufactured by Kyoeisha Chemical, number of energy ray-curable functional groups: 6, number of hydroxyl groups: 0, weight average molecular weight 563, number of energy ray-curable functional groups (E): 6)

A2: dipentaerythritol triacrylate monomer (trade name light acrylate PE-3A, manufactured by Kyoeisha Chemical, number of energy ray-curable functional groups (E): 3, number of hydroxyl groups: 1, weight average molecular weight 298)

A' 1: Epoxy acrylate monomer (trade name: epoxy ester 200 PA, Kyoeisha Chemical Co., Ltd., number of energy ray-curable functional groups (E): 2, number of hydroxyl groups: 2, weight average molecular weight 332)

A' 2: 2-hydroxy-3-acryloyloxypropyl methacrylate monomer (trade name: NK ester 701 A, manufactured by Shin-Nakamura Chemical Co., Ltd., number of energy ray-curable functional groups (E): 2, number of hydroxyl groups: 1 , weight average molecular weight 214)

A' 3: Polyethylene glycol #1000 diacrylate monomer (trade name: NK ester A-1000, manufactured by Shin-Nakamura Chemical Co., Ltd., number of energy ray-curable functional groups (E): 2, number of hydroxyl groups: 0, weight average molecular weight 1108)

A' 4: methoxypolyethylene glycol #400 acrylate monomer (trade name: NK Ester AM-90G, manufactured by Shin-Nakamura Chemical Co., Ltd., number of energy ray-curable functional groups (E): 1, number of hydroxyl groups: 0, weight average molecular weight 454)

(B) UV absorber

B: Energy ray-curable benzotriazole-based ultraviolet absorber (trade name: RUVA-93, manufactured by Otsuka Chemical Co., Ltd., the maximum value of absorbance in the wavelength range of 280 nm to 370 nm in a 0.0619 mmol/l solution dissolved in dichloromethane is 0.6 or higher)

B' 1: Benzotriazole-based UV absorber that is not energy ray-curable (trade name: Tinuvin 928, manufactured by BASF)

B'2: Benzophenone-based UV absorber that is not energy ray-curable (trade name: LS-907, manufactured by Ipposha Yugo Co., Ltd.)

(C) (meth)acrylate oligomer (energy-ray-curable oligomer)

C1: aliphatic urethane acrylate oligomer (trade name: Artresin UN-904, manufactured by Negami Kogyo Co., Ltd., number of energy ray-curable functional groups: 10, weight average molecular weight 4900)

C2: aliphatic urethane acrylate oligomer (trade name: Art Resin UN-3320 HS, manufactured by Negami Kogyo Co., Ltd., number of energy ray-curable functional groups: 15, weight average molecular weight 4900)

(D) light stabilizer

(D) component: hindered amine light stabilizer (trade name: Tinuvin 765, manufactured by BASF)

(E) photopolymerization initiator

E1-1: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name: Irgacure 819, manufactured by BASF)

E1-1:2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (trade name: Irgacure 379, manufactured by BASF)

E2: 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan1-one (trade name: Irgacure 907, manufactured by BASF)

E1,2:2,2-dimethoxy-1,2-diphenylethan-1-one (trade name: Irgacure 651, manufactured by BASF)

1. Preparation of coating composition and hard coating film

(A) (meth)acrylate monomer shown in Tables 1-5, (B) ultraviolet absorber, and (C) (meth)acrylate oligomer were weighed by solid content ratio (mass part) shown in Table 1. Details of each component are as described above. Further (D) 1 part by mass of a light stabilizer, (E) as a photopolymerization initiator (E-1) bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name: Irgacure 819, manufactured by BASF) and ( E-2) 3 parts by mass and 4 parts by mass of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (trade name: Irgacure 907, manufactured by BASF), respectively added. Moreover, about Examples 4-14 shown in Table 2, the photoinitiator of Table 2 was added by mass ratio shown in Table 2. Each of the above components was mixed with 75 parts by mass of methyl ethyl ketone (MEK) and 75 parts by mass of propylene glycol monomethyl ether (PGM) to obtain coating compositions (solid content: 43%) of Examples and Comparative Examples. Next, the coating compositions of Examples and Comparative Examples were applied to one side of a 188 μm thick polyethylene terephthalate film (trade name: Cosmoshine A4300, manufactured by Toyobo Corporation) as a transparent support by a bar coating method, and dried at 80° C. for 2 minutes , a high-pressure mercury lamp was irradiated at 300 mJ/cm ² and cured to form a hard coat layer having a film thickness of 6 μm, thereby obtaining hard coat films of Examples and Comparative Examples.

2. Evaluation

The hard coating films of the obtained Examples and Comparative Examples were measured or evaluated by the following method for four items of coating film hardness, scratch resistance, weather resistance, and adhesion to a substrate. The results of Examples 1 to 3 and Comparative Examples 1 to 7 are in Table 1, the results of Examples 4 to 14 are in Table 2, the results of Examples 15 to 18 are in Table 3, The results of Examples 19 to 22 are shown in Table 4, and the results of Examples 23 to 25 are shown in Table 5.

[film hardness]

According to JIS K5400, using a pencil scratch hardness tester, the pencil hardness of the hard coating films of Examples and Comparative Examples was measured. Specifically, with the side having the hard coating layer of the hard coating film facing up, the pencil is set at an angle of 45 degrees, and the pencil is scratched 5 mm with a load of 1000 g from the top. was recorded.

[Scratch resistance]

<Initial scratch resistance>

As a steel wool test, a steel wool of #0000 ^{was wrapped around a 3 cm 2} columnar jig and reciprocated with a load of 500 g on the hard coating layer of the hard coating films of Examples and Comparative Examples. The number of times immediately before the occurrence of the scratch was recorded as an evaluation value of scratch resistance in the initial stage.

<Scratch resistance after moisture resistance test>

Using the hard coating films of Examples and Comparative Examples after the moisture resistance test to be described later, the measurements were performed in the same manner as in the initial steel wool test, and the number of times immediately before the first wound was recorded as the evaluation value of the scratch resistance after the moisture resistance test did.

[Weather resistance (Δb)]

As a weather resistance test, in accordance with ASTM G-154, using a QUV ultraviolet fluorescence accelerator (manufactured by Q-LAB), the hard coating films of Examples and Comparative Examples were irradiated with ultraviolet rays using a UVA340 lamp in an environment of 60° C. for 8 hours. , and left in a dark room under a condensation environment at room temperature of 50° C. for 4 hours to condense each hard coating film. This was made into 1 cycle, and 12 cycles were performed. The degree of yellowing (Δb) after 12 cycles was measured using a spectrophotometer (trade name: CM-5, manufactured by Konica Minolta Sensing Co., Ltd.) and recorded as an evaluation value of weather resistance.

[Material Adhesion]

<Initial substrate adhesion>

As a substrate adhesion test, according to the checkerboard tape method of JIS K5400, the cellophane adhesive tape specified in JIS Z1522 was applied to the hard coating layer of the hard coating films of Examples and Comparative Examples by making cuts so that 100 spaces with a gap of 1 mm were formed. After peeling, the number of coating films remaining on the transparent support was visually counted and recorded as an evaluation value of the adhesion to the base material in the initial stage.

<Adhesiveness of substrate after weathering test>

The hard coat film after the weather resistance test was used, and it was measured in the same manner as in the initial substrate adhesion test, and was recorded as an evaluation value of the substrate adhesion after the weather resistance test.

<Adhesiveness of substrate after moisture resistance test>

As a moisture resistance test, after leaving it to stand for 550 hours in an environment of a temperature of 60° C. and a relative humidity of 90% R.H., it was measured in the same manner as in the initial substrate adhesion test, and recorded as an evaluation value of adhesion to the substrate after the moisture resistance test.

Table 1 shows the evaluation results of various properties of the hard coating films of Examples 1 to 3 and Comparative Examples 1 to 7.

It was found that the hard coating film obtained from the coating composition of Comparative Example 1 containing no oligomer component and using the high hardness monomer (A2) having three energy ray-curable functional groups had good hardness and scratch resistance. However, in the coating composition of Comparative Example 1, cure shrinkage was large, and a large warpage occurred in the hard coating layer. Further, it was confirmed that the hard coat film of Comparative Example 1 had low initial substrate adhesion, and a further significant decrease was observed after the weather resistance test and after the moisture resistance test, making it unsuitable for practical use. In Comparative Example 1, since it did not have an oligomer, it is thought that cure shrinkage became large. Moreover, when A1 was used instead of A2, the same cure shrinkage was recognized. In addition, it was confirmed that the hard coat film of Comparative Example 1 had insufficient weather resistance. Although the number of hydroxyl groups of A2 is 1, in Comparative Example 1, since the oligomer is not included, the amount of hydroxyl groups occupied in the whole coating composition is large, and it is thought that it is the cause that unreacted hydroxyl groups remain|survive even after hardening.

Although not described in the table, in the hard coating film obtained from the coating composition containing 100 parts by mass of C1, which is an oligomer component, without a monomer component, pencil hardness and scratch resistance are good, but sufficient adhesion to the substrate can be obtained. It was confirmed that no

On the other hand, in Example 1 containing the monomer component A1 and the oligomer component C1, Example 2 containing the monomer component A2 and the oligomer component C1, and Example 3 containing the monomer component A1 and the oligomer component C2, all of the coating films It was found that a hard coating film excellent in hardness, scratch resistance, weather resistance and adhesion to a substrate could be obtained.

On the other hand, the hard coating composition obtained from the coating composition of Comparative Example 2 containing monomer component A'1 (weight average molecular weight: 332, hydroxyl group: 2, number of energy ray-curable functional groups: 2) and oligomer component C1 (mass average molecular weight: 4900) In the coating film, compared with Examples 1-3, hardness and scratch resistance fell. Moreover, it was also confirmed that weather resistance fell, it yellowed after ultraviolet irradiation, and adhesiveness with a board|substrate fell after a weather resistance test and a moisture resistance test. Since A' 1 has two hydroxyl groups, it is thought that the fall of the said characteristic is the influence of the water which adsorb|sucked to the residual hydroxyl group and/or residual hydroxyl group.

Hard coating film obtained from the coating composition of Comparative Example 3 containing monomer component A'2 (weight average molecular weight: 214, hydroxyl group: 1, number of energy ray-curable functional groups: 2) and oligomer component C1 (weight average molecular weight: 4900) Also, compared with Examples 1 to 3, the hardness and scratch resistance were lowered. It is considered that this originates in the weight average molecular weight of A'2 being as small as 214. In addition, in the hard coat film of Comparative Example 3, it was also confirmed that the weather resistance was lowered, yellowed after ultraviolet irradiation, and the adhesion to the substrate was lowered after the weathering test and the moisture resistance test. Although the number of hydroxyl groups in A' 2 is one, since the molecular weight is small, the number of hydroxyl groups occupied in the entire coating composition is large, and excessive hydroxyl groups remain even after curing. It can be thought that a decrease in

A hard coating film obtained from the coating composition of Comparative Example 4 containing monomer component A'3 (weight average molecular weight: 1108, hydroxyl group: 0, number of energy ray-curable functional groups: 2) and oligomer component C1 (weight average molecular weight: 4900) Also, compared with Examples 1 to 3, the hardness and scratch resistance were lowered. This is considered to originate in that the weight average molecular weight of A'3 was large at 1108, and the monomer component A'3 did not get into the gap|interval of an oligomer component, but the crosslinking density did not rise. In addition, in the hard coat film of Comparative Example 4, it was also confirmed that the adhesion to the substrate was lowered after the weathering test and the moisture resistance test. In Comparative Example 4, since the molecular weight of the monomer component is large, the crosslinking density is not improved, and bonding with the surface of the substrate is difficult to form.

A hard coating film obtained from the coating composition of Comparative Example 5 containing monomer component A'4 (weight average molecular weight: 454, hydroxyl group: 0, number of energy ray-curable functional groups: 1) and oligomer component C1 (weight average molecular weight: 4900) Also, compared with Examples 1 to 3, the hardness and scratch resistance were significantly lowered. It is thought that this originates in the crosslinking reaction which sufficient number of energy-beam-hardenable functional groups of A'4 does not advance to one. Moreover, in the hard coat film of Comparative Example 5, it was also confirmed that the weather resistance and adhesion to the substrate at the initial stage were low, and the adhesion to the substrate was further reduced after the weather resistance test and after the moisture resistance test. As described above, in Comparative Example 5, the number of energy ray-curable functional groups is small, sufficient crosslinking reaction does not proceed, and it is considered that the initial adhesion with the base material is low. Moreover, since it is a low crosslinking density, it is thought that it is easy to deteriorate in ultraviolet irradiation or a high-humidity environment as a cause of the fall of weather resistance and the base material adhesiveness after various tests.

In Comparative Examples 6 and 7, in which a non-energy-ray-curable ultraviolet absorber was used instead of B1, which is an energy ray-curable ultraviolet absorber, the hardness and scratch resistance were lower than in Examples, and the substrate after the weather resistance test and the moisture resistance test It was found that the adhesion was lowered.

From the above results, the coating composition of the present invention containing a (meth)acrylate monomer having a predetermined molecular weight, the number of energy ray-curable functional groups and the number of hydroxyl groups, an energy ray-curable oligomer having a predetermined molecular weight, and an energy ray-curable functional group-containing ultraviolet absorber It was found that excellent scratch resistance, weather resistance and adhesion to the substrate can be obtained in the hard coating film obtained from

Table 2 shows the evaluation results of the adhesion to the substrate of the hard coat films of Examples 4 to 14.

In Examples 4 to 14, (A) (meth)acrylate monomer, (B) ultraviolet absorber, (C) acrylate oligomer, and (D) light stabilizer in the same type and blending amount as in Example 1 (E ) The type and mixing ratio of the photopolymerizer were changed. In Example 4, 7 parts by mass of only E1 was added as a photopolymerizer, and in Example 9, 7 parts by mass of only E2 was added. added. Here, compared to Examples 4 and 9 containing either E1 or E2, Examples 1, 5 to 8 containing E1 and E2 showed that the adhesion to the substrate was improved after the weather resistance test and after the moisture resistance test. could In particular, in Examples 1, 5-6, the base material adhesiveness after a moisture resistance test improved significantly.

Further, in Example 10, two types of photopolymerization initiators E1 having a maximum absorbance value of 0.1 or more in the wavelength range of 340 nm to 400 nm of 0.01 mass % methanol solution or acetonitrile solution were added, but E1 and E2 were used in combination. As in the above examples, the effect of significantly suppressing the decrease in adhesion to the substrate after the weather resistance test and the moisture resistance test was not recognized. Moreover, in Example 11, the maximum value of the absorbance in the wavelength range of 340 nm to 400 nm of 0.01 mass % methanol solution or acetonitrile solution is 0.1 or more, while 220 nm to 280 nm in 0.001 mass % methanol solution One type of photopolymerization initiator having a maximum absorbance value of 0.1 or more in the wavelength range of was added. However, like the Example in which E1 and E2 were used together, the effect that the fall of the base material adhesiveness after a weather resistance test and after a moisture resistance test was suppressed significantly was not acquired.

In Examples 12 to 14, the types and ratios of the photoinitiators E1 and E2 (E1:E2=3:4) were the same as in Example 1, and the mass ratio of the total amount of the photoinitiators E1 and E2 was changed. The mass ratios of the total amounts of Example 12, Example 1, Example 13, and Example 14, respectively, E1 and E2 are 3.5, 7, 10.5 and 14. In any of the Examples, it was confirmed that excellent adhesion to the substrate was maintained both after the weather resistance test and after the moisture resistance test.

From the above result, it was confirmed that it is effective for the improvement of base-material adhesiveness to use together two types of photopolymerizers which have a predetermined|prescribed absorbance in a predetermined|prescribed wavelength range.

Table 3 shows various evaluation results of the hard coat films of Examples 15 to 18.

In Examples 12 to 15, (A) (meth) acrylate monomer, (B) ultraviolet absorber, (C) (meth) acrylate oligomer, (D) light stabilizer, (E) type of photopolymerizer and (B) The compounding quantity of a ultraviolet absorber, (D) light stabilizer, and (E) photopolymerizer was the same as that of Example 1, and the compounding ratio of (A) (meth)acrylate monomer and (C)(meth)acrylate oligomer was changed.

Here, since the monomer (A1) of high hardness was used, pencil hardness and scratch resistance improved with the increase of the amount of monomers. Moreover, it turned out that the outstanding weather resistance and base material adhesiveness can also be obtained also about any Example. In particular, in Example 16, Example 1, and Example 17 in which the content ratio of (A) component and (C) component is the range of 3:97-50:50 by mass ratio, the base material adhesiveness after a moisture resistance test is large. improvement was confirmed.

Table 4 shows various evaluation results of the hard coat films of Examples 19 to 22.

In Examples 19 and 22, a hard coat film was produced and evaluated in the same manner as in Example 1, except that the thickness of the hard coat layer was changed as shown in Table 4. It was confirmed that the scratch resistance was further improved by increasing the thickness of the hard coat layer to 3 µm, 6 µm, and 15 µm. However, it was found that sufficient scratch resistance, substrate adhesion and weather resistance could be obtained for any of the Examples.

In Examples 21 and 22, as shown in Table 4, a hard coat film was produced and evaluated in the same manner as in Example 1 except that the addition amount of the ultraviolet absorber (B1) was changed. It was found that sufficient scratch resistance, substrate adhesion and weather resistance could be obtained for any of the Examples.

Table 5 shows various evaluation results of the hard coat films of Examples 23 to 25.

In Examples 23 and 25, a hard coat film was produced and evaluated in the same manner as in Example 1 except that the amount of (D) light stabilizer added to the coating composition was changed as shown in Table 5. It was found that sufficient scratch resistance, weather resistance and adhesion to the substrate could be obtained for any of the Examples.

Claims (9)

(A) an energy ray-curable (meth)acrylate monomer having a weight average molecular weight of 250 or more and 1000 or less, the number of energy ray-curable functional groups is 2 or more and 9 or less, and the number of hydroxyl groups is 1 or less, (B) an energy ray-curable functional group-containing ultraviolet absorber and ( C) A weight average molecular weight of 4900 or more and 20000 or less, the number of energy ray-curable functional groups contains a polyfunctional urethane (meth)acrylate oligomer of 10 or more and 20 or less, and the mass ratio of the component (A) and the component (C) ((A) Component: (C)component) is 3:97-50:50, The coating composition characterized by the above-mentioned. The method according to claim 1, wherein (E1) a 0.01 mass % methanol solution or an acetonitrile solution with a maximum absorbance value in a wavelength range of 340 nm to 400 nm of 0.1 or more, and (E2) a 0.001 mass % methanol solution or a photopolymerization initiator having a maximum absorbance value of 0.1 or more in the wavelength range of 220 nm to 280 nm of the acetonitrile solution, the coating composition characterized in that it further contains. The coating composition according to claim 1, wherein the component (B) is an ultraviolet absorber having a maximum absorbance value of 0.6 or more in a wavelength range of 280 nm to 370 nm in a 0.0619 mmol/l dichloromethane solution. A hard coat film, comprising, on at least one side of a transparent support, a hard coat layer obtained from the coating composition according to any one of claims 1 to 3. The hard coating film according to claim 4, wherein the hard coating layer has a thickness of 0.5 μm or more and 20 μm or less. The hard coating film according to claim 4, wherein the adhesion between the hard coating layer and the transparent support is 90/100 or more based on JIS K5400. 5. The method according to claim 4, wherein the adhesion between the hard coating layer and the transparent support after the moisture resistance test in an environment of a temperature of 60°C and a relative humidity of 90%RH for 550 hours is 90/100 or more based on JIS K5400. hard coating film. 5. The hard coating film according to claim 4, wherein the degree of yellowing (Δb) after 12 cycles of the weathering test as stipulated in ASTM G-154 is less than 1.
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