JP-7855340-B2 - Adhesives and/or adhesives

Inventors

• 水野 大輔
• 雨宮 虎太朗
• 仲野 武史

Assignees

• 日東電工株式会社

Dates

Publication Date

20260508

Application Date

20211130

Claims (5)

1. The polymer contains polymers having irreversibly degradable bonds within the molecule that break upon external stimuli and do not subsequently recombine, and polymers that do not have irreversibly degradable bonds . A tack layer and/or adhesive layer having a shear storage modulus (G') of 1.0 × 10² to 5.0 × 10⁶ Pa at 25°C after external stimulation .
2. The adhesive layer and/or bonding layer according to claim 1, wherein the irreversibly decomposable bond is a bond containing a nitrobenzyl group.
3. The adhesive layer and/or bonding layer according to claim 1 or 2, wherein the polymer having the irreversibly degradable bond within the molecule is a thermoplastic resin and/or a thermosetting resin.
4. The adhesive layer and/or bonding layer according to any one of claims 1 to 3, wherein the polymer having the irreversibly degradable bond within the molecule is a polymer in which a network structure is formed by bonding or entanglement of molecules, or a polymer capable of forming the network structure.
5. An adhesive layer and/or bonding layer according to any one of claims 1 to 4, for use in optical applications.

Description

This invention relates to adhesives and/or bonding agents, more specifically, to an adhesive layer capable of exhibiting tackiness, a bonding agent layer capable of exhibiting bonding properties, a composition capable of forming the above adhesive layer (adhesive composition), and a composition capable of forming the above bonding agent layer (bonding composition). Among optical devices such as displays, thin, flexible displays, exemplified by OLEDs, are constructed by laminating multiple optical films or thin-layer devices. Furthermore, devices requiring flexibility, such as pressure-sensitive sensors, are constructed by laminating a pressure-sensitive element and a substrate (Patent Document 1). Liquid curing resins, adhesives, and other similar materials are selected as interlayer fillers in these laminates. Adhesives and other similar materials are preferred from the viewpoints of improving workability, preventing warping due to curing shrinkage, and enhancing flexibility through stress distribution. The above-mentioned adhesives, in particular, play a role in distributing and mitigating stress generated by bending and folding in flexible members. This function is said to be more efficiently expressed the more flexible the adhesive is (Patent Document 2), and therefore, flexible adhesives are used. Japanese Patent Publication No. 2012-159463Japanese Patent Publication No. 2020-109177 This diagram shows a schematic cross-sectional view of an adhesive sheet or adhesive sheet 10 with a release liner, in which the adhesive layer or bonding layer 1 of the present invention is formed on a release liner 2. [Adhesives, bonding agents] In this specification, "adhesion" refers to the property of two surfaces adhering tightly to each other based on cohesive forces derived from the chemical structure of the composition in response to external pressure (e.g., minute pressure), and being able to be separated if necessary. In contrast, "bonding" refers to the property of two surfaces being firmly joined together by a chemical reaction (curing) of the composition, producing a cured product, and not being intended to be separated. Furthermore, in this specification, "adhesive" may be a non-fluid layered adhesive layer, or a fluid adhesive composition for forming the above-mentioned adhesive layer. Similarly, "adhesive" may be a non-fluid layered adhesive layer, or a fluid adhesive composition for forming the above-mentioned adhesive layer. The adhesive and/or bonding agent of the present invention contains at least a polymer having irreversibly degradable bonds within its molecule that break upon external stimuli and do not subsequently recombine, and/or a compound capable of introducing the above irreversibly degradable bonds into the polymer. In this specification, the above polymer may be referred to as "polymer (A)," and the compound capable of introducing the above irreversibly degradable bonds into the polymer may be referred to as "compound (B)." In this specification, "adhesive and/or bonding agent" may be referred to as "adhesive, etc." The external stimulus that triggers the cleavage reaction of the irreversibly degradable bond described above is appropriately selected according to the type of irreversibly degradable bond, and examples include irradiation with active energy rays and heat. In particular, from the viewpoint of enabling separate thermosetting or active energy ray curing reactions and the cleavage reaction when polymer (A) is a thermosetting resin or an active energy ray curable resin, it is preferable that the external stimulus is different from the type of curability when polymer (A) is curable. Specifically, when polymer (A) is a thermosetting resin, irradiation with active energy rays is preferred, and when polymer (A) is an active energy ray curable resin, heat is preferred. The above-mentioned active energy rays are not particularly limited, but examples include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet light and visible light. Ultraviolet light is particularly preferred. The irradiation energy, irradiation time, and irradiation method of the active energy rays are not particularly limited. Examples of light sources for ultraviolet or visible light irradiation include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and LED lamps. The above irreversibly degradable bond can be a known or conventional bond, preferably a bond containing a nitrobenzyl group. In this case, it is easy to introduce the irreversibly degradable bond into the polymer. As the bond containing the nitrobenzyl group, an ester bond formed between nitrobenzyl alcohol (preferably 2-nitrobenzyl alcohol) and a carboxylic acid having a polymerizable functional group is preferred. Polymer (A) can be obtained using compound (B). Examples of compound (B) include monomer components, oligomer compon