Method for producing laminate for configuring image display device, and image display device using the same
View Patent ↗A method for producing a laminate for configuring an image display device is provided, capable of realizing simultaneously unevenness followability and anti-bubble reliability. A method for producing a laminate for configuring an image display device is proposed, comprising the following steps (1) and (2): (1) The step of forming an adhesive composition into the form of a monolayer or a multilayer sheet, and by UV-crosslinking, primary-curing this thereby forming a pre-secondary curing transparent double-sided adhesive sheet. (2) The step of layering two image display device-constituting members via the pre-secondary curing transparent double-sided adhesive sheet and then irradiating ultraviolet light from at least a first image display device-constituting member side, UV-crosslinking through this member and secondary-curing the pre-secondary curing transparent double-sided adhesive sheet.
1. A method for producing a laminate, the method comprising:
forming an adhesive composition into a form of a monolayer or a multilayer sheet on a transparent release sheet;
irradiating the adhesive composition with ultraviolet light through the transparent release sheet;
primary-curing the monolayer or multilayer sheet by UV-crosslinking to obtain a pre-secondary curing transparent double-sided pressure-sensitive adhesive sheet;
peeling the release sheet;
layering two image display device-constituting members via the pre-secondary curing transparent double-sided adhesive sheet; and then
irradiating ultraviolet light from a side of an image display device-constituting member, thereby UV-crosslinking and secondary-curing the pre-secondary curing transparent double-sided adhesive sheet through the member.
2. The method of claim 1 , wherein the pre-secondary curing transparent double-sided adhesive sheet has a wavelength absorption for starting a UV-crosslinking reaction of from 315 nm to 400 nm.
3. The method of claim 1 , wherein an indentation hardness (b) of the transparent double-sided adhesive sheet after the secondary curing is 33≦(b)≦80.
4. The method of claim 1 , wherein an indentation hardness (a) of the pre-secondary curing transparent double-sided adhesive sheet after the primary-curing and an indentation hardness (b) of the transparent double-sided adhesive sheet after secondary curing satisfy a relation (b)−(a)≧2.
5. The method of claim 1 , wherein the irradiating ultraviolet light from a side of an image display device-constituting member comprises irradiating ultraviolet light through a member with a light transmittance of 20% or greater in a wavelength range of 315 to 400 nm.
6. The method of claim 1 ,
wherein, the image display device-constituting members are each laminates comprising a touch panel, an image display panel, a surface protection panel, a polarization film, or any combination thereof.
7. The method of claim 1 , wherein the adhesive composition comprises a (meth)acrylic acid ester series polymer.
8. The method of claim 1 , wherein the adhesive composition is a solvent-free system that does not contain a solvent and is hot-melt formable.
9. The method of claim 1 , wherein a thickness of the monolayer or multilayer sheet is from 50 μm to 1 mm.
10. The method of claim 1 ,
wherein the monolayer or multilayer sheet is a multilayer sheet comprising outermost layers and an intermediate layer, and
a ratio of a thickness of each of the outermost layers to a thickness of the intermediate layer is from 1:1 to 1:20.
11. The method of claim 1 , wherein an indentation hardness of the pre-secondary curing transparent double-sided adhesive sheet after the primary-curing is from 10 to 50.
12. The method of claim 1 , wherein the forming an adhesive composition comprises forming the adhesive composition into a monolayer sheet.
13. The method of claim 1 , wherein the forming an adhesive composition comprises forming the adhesive composition into a multilayer sheet.