WO-2026094671-A1 - OPTICAL LAMINATE AND ARTICLE PROVIDED WITH SAME

WO2026094671A1WO 2026094671 A1WO2026094671 A1WO 2026094671A1WO-2026094671-A1

Abstract

An optical laminate 102 comprises in the following order: a transparent base material 11; a hard coat layer 12; an adhesion layer 13 which is composed of a sputtered film; an optical function layer 14 in which high refractive index layers that are each composed of a sputtered film and low refractive index layers that have a refractive index lower than the high refractive index layers are alternately laminated; and an antifouling layer 15. The hard coat layer 12 contains silica particles (A) that have an average particle diameter of 65 nm or more, and the optical laminate satisfies the condition 1 and the condition 2 described below. Condition 1: The ratio ((A)/(B)) of the Martens hardness (A) on the optical laminate antifouling layer side to the Martens hardness (B) on the hard coat layer side of a laminate having only the transparent base material and the hard coat layer is 3.65 or less. Condition 2: Using a friction testing machine that uses steel wool in accordance with JIS L0849, the difference in contact angle with respect to water before friction and after friction, in which the steel wool is subjected to 200 horizontal reciprocating motions, is 20° or less.

Inventors

MORIYAMA, HIRONOBU
USUI, NAOKI
GU, JIAN

Assignees

デクセリアルズ株式会社

Dates

Publication Date: 20260507
Application Date: 20251017
Priority Date: 20241028

Claims (13)

In an optical laminate having a transparent substrate, a hard coat layer, an optical functional layer including an anti-reflective layer, and an anti-fouling layer in this order, The hard coat layer contains silica particles (A) with an average particle diameter of 65 nm or more, and the optical laminate satisfies the following conditions 1 and 2. Condition 1: The ratio ((A)/(B)) of the Martens hardness (A) measured from the antifouling layer side of the optical laminate to the Martens hardness (B) measured from the hard coat layer side of a laminate having only the transparent substrate and the hard coat layer is 3.65 or less. Condition 2: Using a friction tester that conforms to JIS L0849 and uses steel wool, the difference in contact angle with water before friction and after friction by moving the steel wool horizontally back and forth 200 times is 20° or less.
The optical laminate according to claim 1, wherein the silica particles (A) are surface-modified with functional groups derived from a silane compound.
The optical laminate according to claim 1, wherein the hard coat layer further contains silica particles (B) with an average particle diameter of 55 nm or less.
The optical laminate according to claim 3, wherein the silica particles (B) are surface-modified with functional groups derived from a silane compound.
The optical laminate according to claim 2 or 4, wherein the silane compound is one or more selected from vinyl group-containing silane compounds, (meth)acryloyl group-containing silane compounds, amino group-containing silane compounds, isocyanate group-containing silane compounds, isocyanurate group-containing silane compounds, epoxy group-containing silane compounds, and mercapto group-containing silane compounds.
The optical laminate according to claim 5, wherein the silane compound is a (meth)acryloyl group-containing silane compound.
The hard coat layer contains a binder resin and silica particles (A), The optical laminate according to claim 2, wherein the functional group derived from the silane compound has the same functional group as the binder resin.
The hard coat layer contains a binder resin, silica particles (A), and silica particles (B). The optical laminate according to claim 4, wherein the functional group derived from the silane compound has the same functional group as the binder resin.
The binder resin contains a (meth)acrylate compound, The optical laminate according to claim 7 or 8, wherein the functional group derived from the silane compound is a (meth)acryloyl group.
The optical laminate according to claim 1, wherein the thickness of the hard coat layer is 0.5 μm or more and 100 μm or less.
The optical laminate according to claim 1, wherein the optical functional layer includes a high refractive index layer and a low refractive index layer having a lower refractive index than the high refractive index layer.
The optical laminate according to claim 1, wherein when the optical laminate is bent 180° using a planar body unloaded U-shaped stretch tester with the surface on which the antifouling layer is formed facing inward, the compression ratio C (%) of the optical functional layer, calculated by the following formula (2), satisfies 4.5 ≤ C when the laminate is bent to the smallest bending radius at which no cracks occur, the optical functional layer satisfies 4.5 ≤ C. C (%) = {1-(R3/R1)}×100...(2) (However, R3 is the distance obtained by subtracting the thickness of the optical laminate from half the distance between the plates, and R1 is the distance obtained by subtracting half the thickness of the optical laminate from half the distance between the plates.)
An article comprising an optical laminate according to either claim 1 or 2.

Description

Optical laminate and article containing the same The present invention relates to an optical laminate and an article equipped therewith, and more particularly to an optical laminate used as an anti-reflective film suitable for displays that are bent, such as flexible displays, and an article equipped therewith. This application claims priority with respect to Japanese Patent Application No. 2024-188734, filed in Japan on October 28, 2024, and the contents of that application are incorporated herein by reference. In recent years, foldable displays have been introduced in mobile communication devices such as smartphones and information equipment such as notebook PCs. These displays sometimes utilize optical laminates, such as anti-reflective films, to reduce surface reflection. However, optical laminates used in foldable displays require greater durability against bending compared to non-foldable displays. For example, Patent Document 1 proposes improving the flexibility of a hard-coat film having an optical functional layer consisting of a hard-coat layer and a sputtered film by setting the ratio of the thicknesses of the hard-coat layer to the optical functional layer within a predetermined range. Furthermore, Patent Document 2 describes how the flexibility can be improved by making the hard coat layer and anti-reflective layer from resin. This is a cross-sectional view showing an example of the optical laminate according to this embodiment.This is a cross-sectional view showing another example of the optical laminate of this embodiment.This is a schematic diagram illustrating an example of a manufacturing apparatus that can be used in the manufacturing method of the optical laminate according to this embodiment.This is a schematic diagram illustrating an example of an article equipped with the optical laminate of this embodiment. The following description of this embodiment will be made in detail with reference to the figures as appropriate. The drawings used in the following description may show enlarged versions of key features for convenience in order to clearly illustrate the features of the present invention, and the dimensional ratios of each component may differ from those in reality. The materials, dimensions, etc. exemplified in the following description are examples only, and the present invention is not limited to them; it can be implemented with appropriate modifications within the scope of achieving its effects. In this specification, unless otherwise specified, refractive index refers to the refractive index at a wavelength of 550 nm. [Optical laminate] Figure 1 is a cross-sectional view showing another example of the optical laminate according to this embodiment. The optical laminate 102 shown in Figure 1 is made up of a transparent substrate 11, a hard coat layer 12, an adhesion layer 13, an optical functional layer 14, and an anti-fouling layer 15, all of which are laminated in that order. The adhesion layer 13 is a layer that creates adhesion between the hard coat layer 12 and the optical functional layer 14. The optical functional layer 14 is a layer that exhibits optical functions. Optical functions are functions that control the properties of light, such as reflection, transmission, and refraction, and examples include anti-reflective functions, selective reflection functions, and lens functions. The optical functional layer 14 preferably includes one selected from an anti-reflective layer and a selective reflective layer. Known materials can be used as the anti-reflective layer and the selective reflective layer. Both the anti-reflective layer and the selective reflective layer may be single layers or laminates of multiple layers. Figure 2 is a cross-sectional view showing another example of the optical laminate according to this embodiment. The optical laminate 10 shown in Figure 2 is provided with an anti-reflective layer as the optical functional layer 14 in the optical laminate 102 shown in Figure 1. The optical functional layer 14 (anti-reflective layer), as shown in Figure 2, consists of a laminate in which low refractive index layers 14b and high refractive index layers 14a are alternately laminated. The optical functional layer 14 shown in Figure 2 is laminated in the following order from the transparent substrate 11 side: hard coat layer 12, adhesion layer 13, high refractive index layer 14a, low refractive index layer 14b, high refractive index layer 14a, low refractive index layer 14b, and anti-fouling layer 15. Therefore, the anti-fouling layer 15 is in contact with the low refractive index layer 14b of the optical functional layer 14. The transparent substrate 11 may be formed from a transparent material capable of transmitting light in the visible light range. For example, a plastic film is preferably used as the transparent substrate 11. Specific examples of constituent materials for plastic films include polyester resins, acetate resins, polyethersulfone resins, polyca