Optical film having excellent adhesive strength and durability, and polarizing film comprising same

An optical film comprising:

• a transparent film;
• and
• a coating layer on at least one surface of the transparent film, the coating layer has transparency of 0 to 5 and has a coefficient of friction is from 0 to 0.6;
• wherein the coating layer includes a synthesis of polyester acrylic resin in which a weight ratio of polyester and acryl is 5:5 and a polyurethane-based resin which has a weight average molecular weight from 10,000 to 1,000,000;
• wherein the coating layer is formed using a composition having a synthesis of polyester acrylic resin B as the synthesis of polyester acrylic resin and a polyurethane-based resin D as the polyurethane-based resin, or the coating layer is formed using a composition having a synthesis of polyester acrylic resin C as the synthesis of polyester acrylic resin and a polyurethane-based resin E as the polyurethane-based resin;
• wherein the polyester acrylic resin B has a weight ratio of polyester and acryl of 5:5, the synthesis of the polyester acrylic resin B is prepared by adding glycidylethyl (meth)acrylate and methyl (meth)acrylate, in a weight ratio of 40:60, to polyester resin A, the polyester resin A is prepared by an esterification reaction of ethylene glycol, diethylene glycol, sodium sulfonyl isophthalic acid, and isophthalic acid in a molar ratio of 0.5:0.5:0.1:0.9;
• the polyester acrylic resin C has a weight ratio of polyester and acryl of 5:5, the synthesis of polyester acrylic resin C is prepared by adding glycidylethyl (meth)acrylate and methyl (meth)acrylate, in a weight ratio of 40:60, to an esterification reaction product of ethylene glycol, sodium sulfonyl isophthalic acid, and isophthalic acid in a molar ratio of 1.0:0.1:0.9;
• the polyurethane-based resin D is prepared by dissolving 60 g of methyl ethyl ketone in 48 g of polycarbonate diol having a molecular weight of 2,000, and adding 40 g of isophorone diisocyanate, 12 g of dimethylol propionic acid, and 233 g of water to perform emulsification, then neutralizing with triethylamine and chain extending with isophorone diamine;
• the polyurethane-based resin E is prepared by dissolving 60 g of methyl ethyl ketone in 48 g of a polyester resin prepared by an esterification reaction of ethylene glycol, 2-methyl-1,3-propanediol, adipic acid, and isophthalic acid in a molar ratio of 0.5:0.5:0.5:0.5, then adding 40 g of isophorone diisocyanate, 12 g of dimethylol propionic acid, and 233 g of water to perform emulsification, then neutralizing with triethylamine and chain extending with isophorone diamine;
• wherein a film-forming temperature of the synthesis of polyester acrylic resin B, the synthesis of polyester acrylic resin C, the polyurethane-based resin D and the polyurethane-based resin E are 80° C., 80° C., 0° C., and 5° C., respectively;
• and
• wherein the composition includes the synthesis of polyester acrylic resin in 70.0 parts by weight and the polyurethane-based resin in 30.0 parts by weight, with respect to a total of 100 parts by weight of the synthesis of polyester acrylic resin and the polyurethane-based resin;
• wherein a glass transition temperature of the synthesis of polyester acrylic resin B, the synthesis of polyester acrylic resin C, the polyurethane-based resin D and the polyurethane-based resin E are 60° C., 65° C., 30° C. and 40° C., respectively.