ADHESIVE SHEET AND LAMINATE
To provide an adhesive sheet which exhibits step followability even in a high/low-temperature environment or an ultraviolet irradiation environment and has excellent durability.SOLUTION: There is provided an adhesive sheet which has photocrosslinkability, has a glass transition temperature (Tg) of -...
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Zusammenfassung: | To provide an adhesive sheet which exhibits step followability even in a high/low-temperature environment or an ultraviolet irradiation environment and has excellent durability.SOLUTION: There is provided an adhesive sheet which has photocrosslinkability, has a glass transition temperature (Tg) of -50°C to -40°C, contains a (meth)acrylic copolymer having a weight average molecular weight of 330000 to 400000 and has a tensile stress at a tensile elongation of 2000% before photocrosslinking of 0.3 N/mm2 or less and a tensile modulus before photocrosslinking of 50 kPa or more and 300 kPa or less, wherein when a tensile modulus before photocrosslinking is defined as a and a tensile modulus after photocrosslinking is defined as b, a ratio b/a is less than 3.0, the gel fraction of the photolinked adhesive sheet after photocrosslinking by irradiating ultraviolet rays so that the integrated light quantity is 2000 mJ/cm2 using a high-pressure mercury-vapor lamp having an illuminance of 80 mW/cm2 is 20% or less.SELECTED DRAWING: Figure 1
【課題】本発明は、高低温環境や紫外線照射環境においても優れた段差追従性を発揮し、耐久性にも優れた粘着シートを提供することを課題とする。【解決手段】本発明は、光架橋性を有する粘着シートであって、粘着シートは、ガラス転移温度(Tg)が-50℃~-40℃であり、重量平均分子量が33万~40万の(メタ)アクリル系共重合体を含み、光架橋前の引張伸び率2000%における引張応力が0.3N/mm2以下であり、光架橋前の引張弾性率が50kPa以上300kPa以下であり、光架橋前の引張弾性率をaとし、光架橋後の引張弾性率をbとした場合、b/aが3.0未満であり、照度80mW/cm2の高圧水銀灯を用いて、積算光量が2000mJ/cm2となるように紫外線を照射することで光架橋した光架橋後粘着シートのゲル分率が20%以下となる、粘着シートに関する。【選択図】図1 |
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