Acrylic resin composition, adhesive agent composition, base for adhesive sheet, and adhesive sheet

An acrylic resin composition comprising a polymer containing a unit derived from a monomer represented by the following formula (1):

• R1 represents a hydrogen atom or a methyl group, R2 represents an alkylene group having 2 to 4 carbon atoms, and R3 represents an alkyl group having 1 to 10 carbon atoms, n represents an integer of 1,
• wherein the proportion of the unit derived from the monomer represented by formula (1) contained in the polymer is 60 to 90% by mass with respect to 100% by mass of the total monomer units constituting the polymer,
• the polymer further comprises a unit derived from a carboxylic acid-containing (meth)acrylic monomer and the proportion of the unit derived from the carboxylic acid-containing (meth)acrylic monomer contained in the polymer is 0% by mass or 12.5 to 20% by mass with respect to 100% by mass of the total monomer units constituting the polymer,
• the polymer further comprises a unit derived from (meth)acrylic acid alkyl ester, and the proportion of the unit derived from (meth)acrylic acid alkyl ester contained in the polymer is 0% by mass or 10 to 27.5% by mass with respect to 100% by mass of the total monomer units constituting the polymer,
• the polymer comprises at least one of the unit derived from the carboxylic acid-containing (meth)acrylic monomer and the unit derived from (meth)acrylic acid alkyl ester,
• the acrylic resin composition further comprises at least one crosslinking agent selected from the group consisting of polyfunctional (meth)acrylic monomers, polyfunctional (meth)acrylic oligomers, and bifunctional or higher functional glycidyl group-containing compounds, and
• the tensile strength after the acrylic resin composition is immersed in oleic acid for 24 hours is 50% or more of the value of the tensile strength before being immersed in oleic acid.