Waterproof sheet for outdoor tank and method for applying same

A waterproof sheet comprising a rubber base layer and a pressure-sensitive adhesive layer disposed thereon,

• wherein the rubber base layer comprises a silicone rubber having a JIS-A hardness of 25 to 80, a tensile strength of at least 5 MPa, an elongation of 200 to 700%, a crescent tear strength of at least 7 kN/m, and a thickness of 0.2 to 5 millimeters, and
• wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive adhesive silicone resin or gel formed of an addition-cure silicone rubber composition comprising:
• (A) 30 to 90 parts by weight of an organopolysiloxane containing at least two silicon-bonded alkenyl groups in a molecule;
• (B) 10 to 70 parts by weight of a resinous copolymer predominantly comprising R3SiO1/2 units and SiO2 units wherein R is a substituted or unsubstituted monovalent hydrocarbon group and contains alkenyl, a molar ratio of R3SiO1/2 units to SiO2 units (R3SiO1/2/SiO2) being in a range of 0.5/1 to 1.5/1;
• (C) 0.5 to 30 parts by weight of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms (SiH groups) in a molecule;
• and
• (D) an addition reaction catalyst in an amount that provides 0.5 to 1000 ppm of platinum group metal based on the total weight of components (A) and (B), said pressure-sensitive adhesive layer having a hardness lower than the hardness of the rubber base, the hardness of the pressure-sensitive adhesive layer being in a range of 1 to 40 on the Asker C hardness scale, said pressure-sensitive adhesive layer having a thickness of 0.3 to 3 millimeters.