Graft polymer

A method for producing an oil-resistant agent comprising a long-chain hydrocarbon group-containing non-fluorine polymer, comprising:

• a step of polymerizing a monomer containing a monomer (a) in the presence of a bio-based material, wherein the monomer (a) is represented by the following formula:
• CH2═C(—X)—C(═O)—Y(R)k
• wherein R is each independently a hydrocarbon group having 7 to 40 carbon atoms,
• X is a hydrogen atom, a monovalent organic group or a halogen atom,
• Y is a group composed of at least one selected from a divalent to tetravalent hydrocarbon group having one carbon atom, —C6H4—, —O—, —C(═O)—, —S(═O)2— or —NH—, and
• k is 1 to 3,
• wherein the long-chain hydrocarbon group-containing non-fluorine polymer is bonded to the bio-based material by graft modification to form a graft polymer,
• wherein the graft polymer has a biobased content according to ASTM D6866 of 40% or more,
• wherein the oil-resistant agent does not contain a substrate and is configured to be applied to the substrate, and
• wherein the oil-resistant agent is a water dispersion.