Laminate

1. A laminate comprising:

a fiber layer formed of cellulose fibers having a fiber width of 1000 nm or less;

a resin layer; and

an adhesive layer directly laminated between the fiber layer and the resin layer,

wherein the fiber layer comprises hydrophilic macromolecules having a molecular weight of 50,000 or more and 8,000,000 or less,

the resin layer comprises a polymer of acrylic monomers,

the adhesive layer comprises a functional group (A), which forms a covalent bond with a (meth)acryloyl group included in the resin layer, and at least one selected from a functional group (B) and a hydrolyzed group of the functional group (B), which forms a covalent bond with a hydroxy group of ultrafine cellulose fibers included in the fiber layer, and

the thickness of the fiber layer is 30 μm or more and 500 μm or less.

2. The laminate according to claim 1 , wherein the functional group (A) is at least two selected from a (meth)acryloyl group and a group represented by H 2 C=CR 2 —CH(—OH)—, wherein R 2 represents a hydrogen atom or a methyl group.

3. The laminate according to claim 1 , wherein the functional group (B) is at least one selected from an isocyanate group, a carbodiimide group, an epoxy group, an alkoxysilyl group, a silanol group and an oxazoline group.

4. The laminate according to claim 1 , wherein the adhesive layer comprises a polymer having the functional group (A) and a compound having the functional group (B).

5. The laminate according to claim 1 , wherein the adhesive layer further comprises a polymerization initiator.

6. The laminate according to claim 1 , wherein the resin layer further comprises a polymerization initiator.

7. The laminate according to claim 1 , produced by applying a composition comprising a resin having the functional group (A) and a hydroxy group, as well as a compound having at least two functional groups (B) onto at least one surface of the fiber layer, to form the adhesive layer, and applying a resin composition comprising acrylic monomers onto the adhesive layer to form the resin layer.

8. The laminate according to claim 1 , wherein the adhesive layer comprises a urethane (meth)acrylate resin.

9. The laminate according to claim 8 , wherein the resin layer comprises at least one selected from a polycarbonate resin and an acrylic resin.

10. The laminate according to claim 8 , wherein the resin layer has a first layer arranged on a side of the adhesive layer and a second layer arranged on one side of the first layer, which is on the opposite side of the adhesive layer; and

wherein the first layer comprises an acrylic resin and the second layer comprises a polycarbonate resin.

11. The laminate according to claim 10 , wherein the first layer comprises an alkyl (meth)acrylate resin.

12. The laminate according to claim 10 , wherein the first layer comprises an epoxy (meth)acrylate resin.

13. The laminate according to claim 10 , wherein the resin layer is a coextruded film having the first layer and the second layer.

14. The laminate according to claim 8 , wherein the urethane (meth)acrylate resin comprised in the adhesive layer comprises urethane units and acrylic units, and when the content of the urethane units (% by mass) is defined as P and the content of the acrylic units (% by mass) is defined as Q, P/Q is 0.1 or more and 0.9 or less.

15. The laminate according to claim 1 , wherein the cellulose fibers have phosphoric acid groups or substituents derived from the phosphoric acid group.

16. The laminate according to claim 1 , wherein the functional group (A) is at least one selected from a (meth)acryloyl group and a group represented by H 2 C=CR 2 —CH(—OH)—, wherein R 2 represents a hydrogen atom or a methyl group, and

the functional group (B) is at least one selected from an isocyanate group, a carbodiimide group, an epoxy group, an alkoxysilyl group, a silanol group and an oxazoline group.