US 12,221,562 B2
Adhesive sheet
Shuji Takagi, Tokyo (JP); Koji Tsuda, Sagamihara (JP); and Pradip K. Bandyopadhyay, Austin, TX (US)
Assigned to 3M Innovative Properties Company, St. Paul, MN (US)
Appl. No. 17/056,453
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed May 22, 2019, PCT No. PCT/US2019/033597
§ 371(c)(1), (2) Date Nov. 18, 2020,
PCT Pub. No. WO2019/226819, PCT Pub. Date Nov. 28, 2019.
Claims priority of application No. 2018-098572 (JP), filed on May 23, 2018.
Prior Publication US 2021/0207010 A1, Jul. 8, 2021
Int. Cl. C09J 163/04 (2006.01); C09J 7/25 (2018.01); C09J 7/26 (2018.01); C09J 7/35 (2018.01)
CPC C09J 163/04 (2013.01) [C09J 7/255 (2018.01); C09J 7/26 (2018.01); C09J 7/35 (2018.01); C09J 2301/124 (2020.08); C09J 2301/204 (2020.08); C09J 2301/412 (2020.08); C09J 2401/006 (2013.01); C09J 2463/00 (2013.01); C09J 2467/006 (2013.01)] 15 Claims
OG exemplary drawing
 
1. An adhesive sheet comprising:
a substrate;
two thermally expandable adhesive layers each provided on either side of the substrate; and
two adhesive permeable layers each provided on a surface of the two thermally expandable adhesive layers, the adhesive permeable layers being permeable to the adhesive at the time of thermal expansion of the adhesive,
wherein the adhesive permeable layers are non-woven fabrics, and
wherein a basis weight of the nonwoven fabric is from 10 to 30 g/m2 and wherein a thickness of the non-woven fabrics is not greater than 50 μm, and wherein the adhesive sheet is tack-free prior to the time of thermal expansion of the adhesive.