Composition and film

1. A method for producing an optical element having a cured layer having a concavo-convex structure, the method comprising:

forming a composition layer on a base material by utilizing a composition containing a polymerizable compound and a photo initiator;

forming a pattern formative layer by pressure-contacting a mold having the concavo-convex structure on a surface of the composition layer and then transferring the concavo-convex structure to the composition layer; and

forming the cured layer having the concavo-convex structure by photo-curing the pattern formative layer,

wherein the polymerizable compound contains both:

(a) a urethane (meth)acrylate monomer having a molecular weight of 400 or more; and

(b) a (meth)acrylate monomer having at least one of an alicyclic structure or a heteroalicyclic structure, the (meth)acrylate monomer (b) being other than the urethane (meth)acrylate monomer (a),

wherein the polymerizable compound has a composition ratio, by mass, of (a) to (b),

wherein the mass of the urethane (meth)acrylate monomer (a) is from less than 100 parts by mass to 36 parts by mass based on 100 parts by mass of the polymerizable compound, and

wherein the mass of the (meth)acrylate monomer (b) is from greater than 0 parts by mass to 60 parts by mass based on 100 parts by mass of the polymerizable compound, respectively,

wherein the composition contains 0.005 to 0.5 part by mass of the photo initiator based on 100 parts by mass of the polymerizable compound, and

wherein a film thickness of the cured layer having the concavo-convex structure is within the range of 0.5 mm to 1 cm.

2. The method according to claim 1 , wherein at least one of (a) the urethane (meth)acrylate monomer and (b) the (meth)acrylate monomer contains a monomer having a methacryloyl group.

3. The method according to claim 1 , wherein the polymerizable compound contains a monomer having a polymerizable group, except for a (meth)acryloyl group.

4. The method according to claim 1 , wherein the polymerizable compound further contains a monomer (c) having a ring structure.

5. The method according to claim 4 , wherein at least one of monomers (b) and (c) contains a monomer with a molecular weight greater than or equal to 400.

6. The method according to claim 1 , wherein the urethane (meth)acrylate monomer (a) has a ring structure.

7. A method for producing an optical element having a cured layer having a concavo-convex structure, the method comprising:

utilizing a composition comprising:

100 parts by mass of a polymerizable compound comprising both:

(a) a urethane (meth)acrylate monomer having a molecular weight of 400 or more, and

(b) a (meth)acrylate monomer having at least one of an alicyclic structure or a heteroalicyclic structure, the (meth)acrylate monomer having a ring structure being other than the urethane (meth)acrylate monomer,

a composition ratio, by mass, of (a) to (b),

wherein the mass of the urethane (meth)acrylate monomer (a) is from less than 100 parts by mass to 36 parts by mass based on the 100 parts by mass of polymerizable compound, and

wherein the mass of the (meth)acrylate monomer (b) is from greater than 0 parts by mass to 60 parts by mass based on the 100 parts by mass of polymerizable compound, respectively, and

from 0.005 to 0.5 parts by mass of a photo initiator to form a composition layer on a base material;

pressure-contacting a mold having the concavo-convex structure on a surface of the composition layer and then transferring the concavo-convex structure to the composition layer to form a pattern formative layer; and

photo-curing the pattern formative layer to form the cured layer having a film thickness of from 0.5 mm to one (1) cm.

8. The method according to claim 7 , wherein at least one of the urethane (meth)acrylate monomer and the (meth)acrylate monomer contains a monomer having a methacryloyl group.

9. The method according to claim 7 , wherein the (meth)acrylate monomer contains a monomer with a molecular weight greater than or equal to 400.