Low-Reflection Material

Abstract

A low-reflection material having a fluorine-containing polymer film which can improve abrasion resistance without increasing production cost is provided. In the low-reflection material comprising a transparent substrate, a hard coating layer provided on the transparent substrate, and a fluorine-containing polymer film provided on the hard coating layer, the hard coating layer contains ethylene oxide modified (meth)acrylate resin. Additionally, in the low-reflection material comprising a transparent substrate, a hard coating layer provided on the transparent substrate, a high refractive index layer provided on the hard coating layer, and a fluorine-containing polymer film provided on the high refractive index layer, the high refractive index layer contains ethylene oxide modified (meth)acrylate resin.

Description

EXAMPLES

In the following, the present invention will be explained by Examples. Hereinbelow, “part” means “part by weight”.

Example 1

Production of Hard Coating Layer

The following hard coating coating material was applied to a PET film (trade name: A 4300, produced by Toyobo Co., Ltd.) having a thickness of 100 μm by using a reverse coating method, and after drying at 100° C. for 1 minute, the coating was cured in a nitrogen gas atmosphere by irradiation with ultraviolet light (irradiation distance: 10 cm, irradiation time: 30 seconds) using a converging type high pressure mercury lamp of 120 W/cm. As a result, a hard coating layer having a thickness of 2.5 μm was produced.

Mixing Ratio of Hard Coating Coating Material

49 parts of EO modified trimethylolpropane triacrylate (trade name: TMP-6EO-3A, produced by Kyoeisha Chemical Co., Ltd.),

1 parts of photoinitiator (trade name: IRGACURE 184, produced by Ciba-Geigy Co., Ltd.), and

50 parts of methylethylketone.

The above EO modified trimethylolpropane triacrylate is shown in the following Chemical Formula 16.

(In the chemical formula, the total of 1, m, and n is 6.)

Production of Low Refractive Index Layer

The following low refractive index coating material was applied to the above hard coating layer by using a reverse coating method, and after drying at 100° C. for 1 minute, the coating was cured by irradiation in a nitrogen gas atmosphere with ultraviolet light (irradiation distance: 10 cm, irradiation time: 30 seconds) using a converging type high pressure mercury lamp of 120 W/cm. As a result, a high refractive index layer having a thickness of 0.1 μm was produced, and thereby, a low-reflection material of the present invention having a reflectivity of 1.45% was produced.

Mixing Ratio of Low Refractive Index Coating Material

100 parts of fluorine-containing ultraviolet light curable resin having a carbon-carbon double bond in a side chain (trade name: AR100, total solid concentration: 15%, solvent: MIBK, produced by Daikin Industries, Ltd.),

1 parts of photoinitiator (trade name: IRGACURE 907, produced by Ciba-Geigy Co., Ltd.), and

43 parts of methylisobutylketone.

The above fluorine-containing ultraviolet ray curable resin is a COPolymer which includes a fluorine-containing polymer having a carbon-carbon double bond in a side chain.

Comparative Example 1

A comparative low-reflection material having a reflectivity of 1.46% was produced in the same manner as that in Example 1, except that the mixing ratio was changed to the following ratio.

Mixing Ratio of Hard Coating Coating Material

49 parts of trimethylolpropane triacrylate (trade name: TMP-A, produced by Kyoeisha Chemical Co., Ltd.),

1 part of photoinitiator (trade name: IRGACURE 184, produced by Ciba-Geigy Co., Ltd.), and

50 parts of methylethylketone.

The above trimethylolpropane triacrylate is shown in the following Chemical Formula 17.

(In the chemical formula, the total of 1, m, and n is 6.)

With regard to the low-reflection material of Example 1 and the comparative low-reflection material of Comparative Example 1 as obtained above, total light transmittance, reflectance, and wear resistance were measured and evaluated by the following methods.

The total light transmittance was measured using a HAZE meter (trade name: NDH 2000, produced by Japan Electric Color Co., Ltd.).

5 degree specular reflection was measured at wavelengths of 400 to 700 nm using a spectrophotometer (trade name: UV 3100, produced by Shimadzu Corporation) and was luminosity-corrected in accordance with Japanese Industrial Standard JIS Z-8701, and the reflectivity is shown by a Y value. Here, after the non-measured surface of the film was completely painted with black magic ink, the measurements were carried out.

Steel-wool #0000 produced by Nippon Steel Wool Co., Ltd., was mounted on a paperboard abrasion resistance test machine (produced by Kumagai Riki Kogyo Co., Ltd.), and was rubbed on the surface of the low refractive index layer of the low-reflection material 10 times with a 250 g load. Then, the change in the HAZE value, AHAZE (according to the expression in the following) on the rubbed portion was measured by a HAZE meter. Here, the larger the measured value, the worse the abrasion resistance. Change of HAZE value: ΔHAZE=HAZE value after testing −HAZE value before testing

	TABLE 1
						Abrasion
		Number of		Total Light		Resistance
	Hard Coating	Acryloyl	Number of EO	Transmittance	Reflection	ΔHAZE
	Material	Groups	Modifications	(%)	(%)	(%)
Example 1	TMP-6E0-3A	3	6	93.88	1.45	0.80
Comparative	TMP-A	3	0	93.82	1.46	1.85
Example 1

As is apparent from Table 1, in the low-reflection material of Example 1 according to the present invention, superior abrasion resistance was exhibited by using ethylene oxide modified methacrylate in the hard coating layer, and in contrast, in the low-reflection material of Comparative Example 1, there was a problem in abrasion resistance, and the comparative low-reflection material could not be used in practice.

As explained above, a low-reflection material according to the present invention which comprises a hard coating layer including ethylene oxide modified (meth)acrylate resin provided on a transparent substrate and a fluorine-containing polymer film provided on the hard coating layer, exhibit superior abrasion resistance.

Claims

1. A low-reflection material comprising a transparent substrate, a hard coating layer provided on the transparent substrate, and a fluorine-containing polymer film provided on the hard coating layer, wherein the hard coating layer contains ethylene oxide modified (meth)acrylate resin, andthe ethylene oxide modified (meth)acrylate resin has three (meth)acryloyl groups or more in a monomer molecule.

2. A low-reflection material comprising a transparent substrate, a hard coating layer provided on the transparent substrate, a high refractive index layer provided on the hard coating layer, and a fluorine-containing polymer film provided on the high refractive index layer, wherein the high refractive index layer contains ethylene oxide modified (meth)acrylate resin, andthe ethylene oxide modified (meth)acrylate resin has three (meth)acryloyl groups or more in a monomer molecule.

3. The low-reflection material according to claim 1, wherein the fluorine-containing polymer film contains at least cured material of a radiation curable fluorine-containing polymer having a carbon-carbon double bond in a side chain.

4. The low-reflection material according to claim 2, wherein the fluorine-containing polymer film contains at least cured material of a radiation curable fluorine-containing polymer having a carbon-carbon double bond in a side chain.