Pressure-sensitive adhesive sheet

A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer comprising a base polymer and a rust inhibitor, wherein:

• the base polymer is an acrylic polymer;
• monomeric components constituting the acrylic polymer comprise:
• a carboxy group-containing monomer, and
• a C5-20 alkyl (meth)acrylate at 85% by weight or more and 99% by weight or less of the monomeric components;
• the amount of the carboxy group-containing monomer among the monomeric components is more than 3% by weight,
• the monomeric components constituting the acrylic polymer include an alkyl (meth)acrylate in an amount of 85% by weight or more and 99% by weight or less of the monomeric components, and
• the alkyl (meth)acrylate is at least one monomer selected from the group consisting of pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, and isononyl (meth)acrylate,
• the pressure-sensitive adhesive layer has a relative dielectric constant of 3 or less at 300 kHz,
• the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition comprising a crosslinking agent, the crosslinking agent comprises an isocyanate-based crosslinking agent and a nonisocyanate-based crosslinking agent, the amount of the non-isocyanate-based crosslinking agent is 1/1000 or more and 1/100 or less of the amount of the isocyanate-based crosslinking agent on weight basis, and the rust inhibitor is a compound having a structure represented by the following formula (2):
• wherein, R1 is a substituent on the benzene ring, and R1 is selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a carboxy group, a carboxyalkyl group having 2 to 6 carbon atoms, an amino group, a mono- or di-C1-10 alkylamino group, an amino-C1-6 alkyl group, a mono- or di-C1-10 alkylamino-C1-6 alkyl group, a mercapto group, and an alkoxycarbonyl group having 1 to 6 carbon atoms;
• n is an integer of 0 to 4, and when n is 2 or more, the n substituents R1 may be the same or different R2 is selected from a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an amino group, a mono- or di-C1-10 alkylamino group, an amino-C1-6 alkyl group, a mono- or di-C1-10 alkylamino-C1-6 alkyl group, a mercapto group, and an alkoxycarbonyl group having 1 to 12 carbon atoms;
• R1 and R2 may be the same or different.