Crystalline thermoplastic polyimide resin

1. A thermoplastic polyimide resin comprising a repeating structural unit represented by formula (1) and a repeating structural unit represented by formula (2),

wherein a content ratio of the repeating structural unit of formula (1) with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) is from 40 to 70% by mol:

wherein

R 1 represents a divalent group having from 6 to 22 carbon atoms comprising an alicyclic hydrocarbon structure;

R 2 represents a divalent chain aliphatic group having from 5 to 12 carbon atoms; and

X 1 and X 2 each independently represent a tetravalent group having from 6 to 22 carbon atoms comprising an aromatic ring.

2. The thermoplastic polyimide resin according to claim 1 , wherein R 1 represents a divalent group represented by formula (R1-1) or (R1-2):

wherein

m 11 and m 12 each independently represent an integer of from 0 to 2; and

m 13 to m 15 each independently represent an integer of from 0 to 2.

3. The thermoplastic polyimide resin according to claim 2 , wherein R 1 represents a divalent group represented by formula (R1-3):

4. The thermoplastic polyimide resin according to claim 1 , wherein R 2 represents an alkylene group having from 5 to 12 carbon atoms.

5. The thermoplastic polyimide resin according to claim 4 , wherein R 2 represents a hexamethylene group.

6. The thermoplastic polyimide resin according to claim 1 , wherein R 2 represents a divalent group represented by formula (R2-1) or (R2-2):

wherein

m 21 and m 22 each independently represent an integer of from 1 to 11; and

m 23 to m 25 each independently represent an integer of from 1 to 10.

7. The thermoplastic polyimide resin according to claim 1 , wherein X 1 and X 2 each independently represent a tetravalent group represented by one of formulae (X-1) to (X-4):

wherein

R 11 to R 18 each independently represent an alkyl group having from 1 to 4 carbon atoms;

p 11 to p 13 each independently represent an integer of from 0 to 2;

p 14 , P 15 , P 16 and p 18 each independently represent an integer of from 0 to 3;

p 17 represents an integer of from 0 to 4; and

L 11 to L 13 each independently represent a single bond, an ether group, a carbonyl group or an alkylene group having from 1 to 4 carbon atoms.

8. The thermoplastic polyimide resin according to claim 1 , further comprising a repeating structural unit represented by formula (3),

wherein a content ratio of the repeating structural unit of formula (3) with respect to the total of the repeating structural unit of formula (1) and the repeating structural unit of formula (2) is 25% by mol or less:

wherein

R 3 represents a divalent group having from 6 to 22 carbon atoms comprising an aromatic ring; and

X 3 represents a tetravalent group having from 6 to 22 carbon atoms comprising an aromatic ring.

9. The thermoplastic polyimide resin according to claim 8 , wherein R 3 represents a divalent group represented by formula (R3-1) or (R3-2):

wherein

m 31 and m 32 each independently represent an integer of from 0 to 2;

m 33 and m 34 each independently represent an integer of from 0 to 2;

R 21 , R 22 and R 23 each independently represent an alkyl group having from 1 to 4 carbon atoms, an alkenyl group having from 2 to 4 carbon atoms or an alkynyl group having from 2 to 4 carbon atoms;

P 21 , P 22 and p 23 each represent an integer of from 0 to 4; and

L 21 represents a single bond, an ether group, a carbonyl group or an alkylene group having from 1 to 4 carbon atoms.

10. The thermoplastic polyimide resin according to claim 8 , wherein X 3 represents a tetravalent group represented by one of formulae (X-1) to (X-4):

wherein

p 11 to R 18 each independently represent an alkyl group having from 1 to 4 carbon atoms;

p 11 to p 13 each independently represent an integer of from 0 to 2;

P 14 , P 15 , P 16 and p 18 each independently represent an integer of from 0 to 3;

p 17 represents an integer of from 0 to 4; and

L 11 to L 13 each independently represent a single bond, an ether group, a carbonyl group or an alkylene group having from 1 to 4 carbon atoms.

11. The thermoplastic polyimide resin according to claim 1 , having a melting point of 360° C. or less and a glass transition temperature of 200° C. or more.

12. The thermoplastic polyimide resin according to claim 1 , having an exothermic amount of a crystallization exothermic peak of 5 mJ/mg or more, the crystallization exothermic peak being observed when the resin is melted and then cooled at a cooling rate of 10° C/min or more in a differential scanning calorimeter.

13. A film comprising the thermoplastic polyimide resin according to claim 1 .

14. A fiber comprising the thermoplastic polyimide resin according to claim 1 .

15. A heat-resistant adhesive comprising the thermoplastic polyimide resin according to claim 1 .