Optical adhesive sheet
An optical adhesive sheet having an excellent repulsion resistance and an excellent swelling rate, and a method for manufacturing the same.
1. An optical adhesive sheet, comprising:
a polyethylene foam substrate; and
an adhesive agent layer formed on at least one surface of the substrate, wherein the adhesive agent layer has micro pores capable of being impregnated with a solvent, wherein the adhesive agent layer is formed by curing an adhesive agent composition, which comprises an acrylic copolymer formed by polymerizing a monomer mixture consisting of ethylhexyl acrylate, isobornyl acrylate, and acrylic acid, and
a swelling rate of the adhesive agent layer, which is calculated by the following Equation 1, is from 60% to 90%:
Swelling rate (%)=( W 2 /W 1 )×100 [Equation 1]
where,
W 1 =an initial weight which is a weight of a sample before immersing the sample, which is obtained by cutting a cured adhesive agent layer into a predetermined size, into a solvent, and
W 2 =a post weight which is a weight of a sample obtained by immersing the sample into the solvent, wherein the solvent is chloroform, ethyl acetate, acetone, methanol, ethanol, isopropanol, butanol or dimethylformamide, leaving the sample to stand for a predetermined time, filtering the sample using a filtration device at a temperature from 100° C. to 150° , wherein the filtration device is a 300 mesh steel screen, and then drying the sample.
2. The adhesive sheet of claim 1 , wherein the adhesive agent composition further comprises a photoinitiator selected from the group consisting of a benzoin-based initiator, a hydroxy ketone-based initiator, an amino ketone-based initiator, caprolactam, and a combination thereof.
3. The optical adhesive sheet of claim 1 , wherein the acrylic copolymer is formed by polymerizing the monomer mixture at an ambient temperature of 20 to 30° C. by irradiation with UV light having a UV intensity of 6 to 8 mW/cm 2 .
4. The optical adhesive sheet of claim 3 , wherein a total UV dose irradiated onto the adhesive agent composition at an ambient temperature of 20 to 30° C. is 1,575 mJ/cm 2 to 1,750 mJ/cm 2 .
5. A method for manufacturing an optical adhesive sheet of claim 1 , the method comprising:
forming an adhesive agent composition comprising an acrylic copolymer formed by polymerizing a monomer mixture consisting of ethylhexyl acrylate, isobornyl acrylate and acrylic acid; and
forming an adhesive agent layer by applying the adhesive agent composition onto at least one surface of a polyethylene foam substrate and UV-curing the adhesive agent composition,
wherein the UV-curing is carried out by using UV light having a UV intensity of 6 to 8 mW/cm 2 at an ambient temperature of 20 to 30° C., and
a swelling rate of the adhesive agent layer, which is calculated by the following Equation 1, is from 60% to 90%:
Swelling rate (%)=( W 2 /W 1 )×100 [Equation 1]
where,
W 1 =an initial weight which is a weight of a sample before immersing the sample, which is obtained by cutting a cured adhesive agent layer into a predetermined size, into a solvent, and
W 2 =a post weight which is a weight of a sample obtained by immersing the sample into the solvent, leaving the sample to stand for a predetermined time, filtering the sample using a filtration device, and then drying the sample, and
wherein a total UV dose irradiated onto the adhesive agent composition at the ambient temperature is 1,575 mJ/cm 2 to 1,750 mJ/cm 2 .
6. The method of claim 5 , wherein the adhesive agent composition further comprises a photoinitiator selected from the group consisting of a benzoin-based initiator, a hydroxy ketone-based initiator, an amino ketone-based initiator, caprolactam, and a combination thereof.