Separator for secondary battery, manufacturing method thereof, method for manufacturing secondary battery comprising the separator and secondary battery manufactured by the method

A separator for a secondary battery, comprising:

• a porous polymer substrate;
• a first layer on at least one surface of the porous polymer substrate,
• wherein the first layer comprises inorganic particles and a nonparticulate acrylic polymer having a glass transition temperature of 15° C. or less, wherein the nonparticulate acrylic polymer connects and fixes the inorganic particles;
• and
• a second layer on an upper surface of the first layer,
• wherein the second layer comprises a uniform particulate acrylic polymer, wherein the uniform particulate acrylic polymer has a glass transition temperature in a range of 20° C. to 50° C.,
• wherein in the first layer and the second layer, a slurry containing the inorganic particles, the nonparticulate acrylic polymer, and the uniform particulate acrylic polymer is coated on at least one surface of the porous polymer substrate, and the uniform particulate acrylic polymer has a lower density than the inorganic particles to move to an upper part of the inorganic particles so that the second layer is formed on the upper surface of the first layer.