WE CLAIM:
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1. A medical material which is a copolymer comprising a
hydrophobic unit and a hydrophilic unit,
wherein
the hydrophobic unit has a terminal alkyl group having 2 to 20 carbon atoms in a side chain,
a static contact angle of water on the copolymer is 30 degrees or more and less than 70 degrees, and
the copolymer has only one glass transition temperature in a range of 45°C or higher and lower than 90°C.
2. The medical material according to claim 1, wherein the hydrophobic unit is an alkyl carboxylic acid vinyl ester unit.
3. The medical material according to claim 1 or 2, wherein the hydrophilic unit is a vinylpyrrolidone unit.
4. The medical material according to any one of claims 1 to 3, wherein
the static contact angle of water on the copolymer is 34 degrees or more and less than 50 degrees, and the copolymer has* only one glass transition

temperature in a range of from 70°C or higher and lower than 88°C.
5. A medical separation membrane in which the medical material according to any one of claims 1 to 4 is bonded or attached to a surface of a membrane including a hydrophobic polymer.
6. The medical separation membrane according to claim 5, wherein
the static contact angle of water on the hydrophobic polymer is 70 degrees or more and less than 160 degrees, and
the glass transition temperature of the hydrophobic
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polymer is 50°C or higher and lower than 250°C.
7. The medical separation membrane according to claim 5 or 6, wherein the hydrophobic polymer includes a polymer selected from the group consisting of a polysulfone-based polymer, a polymethacrylate-based polymer, a polyacrylate-based polymer, a polyester-based polymer and a polystyrene-based polymer.
8. A blood purifier including the medical separation membrane according to any one of claims 5 to 7.