Resin composition

1. A resin composition having an initial viscosity change ratio defined by the following relational expression 1 in a range of 1.1 to 5.0, and

having an initial viscosity change ratio defined by the following relational expression 2 of 10 or more,

wherein in the following relational expressions 1 and 2, V 1 is in a range of 100,000 to 500,000 cP, V 2 is 2,000,000 cP or less, and V 3 is 5,000,000 cP or more:

Initial viscosity change ratio= V 2 /V 1   [Relational Expression 1]

Initial viscosity change ratio= V 3 /V 1   [Relational Expression 2]

wherein, V 1 is an initial viscosity, which is a viscosity value as measured at room temperature within 60 seconds after mixing main agent and curing agent of the resin composition, V 2 is a viscosity value measured after leaving the resin composition, in which V 1 has been measured, at room temperature for 5 minutes and V 3 is a viscosity value measured after leaving the resin composition, in which V 1 has been measured, at room temperature for 60 minutes, and when V 1 and V 3 are measured in a shear rate range of 0.01 to 10.0/s using a rheological property measuring device (ARES), they are viscosity values measured at a point of 2.5/s,

wherein the resin composition is a urethane-based resin composition comprising,

a main composition part comprising an ester-based polyol resin; a curing agent composition part comprising a polyisocyanate; and a filler, and

the ester-based polyol resin is an amorphous polyol, in which a crystallization temperature (Tc) and a melting temperature (Tm) are not observed in a DSC (differential scanning calorimetry) analysis, or has a melting temperature (Tm) of less than 15° C.

2. The resin composition according to claim 1 , wherein a dielectric breakdown voltage of a cured product measured 24 hours after mixing the main agent and the curing agent is 10 kV/mm or more.

3. The resin composition according to claim 1 , wherein a mixture of the ester-based polyol resin and polyisocyanate has a glass transition temperature (Tg) of less than 0° C. after curing.

4. The resin composition according to claim 1 , wherein each of the ester-based polyol resin and the polyisocyanate has a viscosity of less than 10,000 cP.

5. The resin composition according to claim 1 , wherein the ester-based polyol resin is represented by the following formula 1 or 2:

wherein, X is a carboxylic acid-derived unit, Y is a polyol-derived unit, n is a number within a range of 2 to 10, and m is a number within a range of 1 to 10.

6. The resin composition according to claim 5 , wherein the carboxylic acid-derived unit X is one or more units selected from the group consisting of a phthalic acid unit, an isophthalic acid unit, a terephthalic acid unit, a trimellitic acid unit, a tetrahydrophthalic acid unit, a hexahydrophthalic acid unit, a tetrachlorophthalic acid unit, an oxalic acid unit, an adipic acid unit, an azelaic acid unit, a sebacic acid unit, a succinic acid unit, a malic acid unit, a glutaric acid unit, a malonic acid unit, a pimelic acid unit, a suberic acid unit, a 2,2-dimethylsuccinic acid unit, a 3,3-dimethylglutaric acid unit, a 2,2-dimethylglutaric acid unit, a maleic acid unit, a fumaric acid unit, an itaconic acid unit and a fatty acid unit.

7. The resin composition according to claim 5 , wherein the polyol-derived unit Y is any one or two or more units selected from the group consisting of an ethylene glycol unit, a propylene glycol unit, a 1,2-butylene glycol unit, a 2,3-butylene glycol unit, a 1,3-propanediol unit, a 1,3-butanediol unit, a 1,4-butanediol unit, a 1,6-hexanediol unit, a neopentyl glycol unit, a 1,2-ethylhexyldiol unit, a 1,5-pentanediol unit, a 1,9-nonanediol unit, a 1,10-decanediol unit, a 1,3-cyclohexanedimethanol unit, a 1,4-cyclohexanedimethanol unit, a glycerin unit and a trimethylolpropane unit.

8. The resin composition according to claim 1 , wherein the polyisocyanate is a non-aromatic polyisocyanate.

9. The resin composition according to claim 8 , wherein the non-aromatic polyisocyanate is an alicyclic polyisocyanate, a carbodiimide-modified alicyclic polyisocyanate, or an isocyanurate-modified alicyclic polyisocyanate.

10. The resin composition according to claim 1 , wherein the filler comprises alumina, AlN (aluminum nitride), BN (boron nitride), silicon nitride, SiC, or BeO.

11. The resin composition according to claim 1 , wherein the filler is contained in an amount of 50 to 2,000 parts by weight relative to 100 parts by weight of the sum of the ester-based polyol resin and polyisocyanate contents.

12. A battery module comprising a module case having a top plate, a bottom plate and sidewalls, wherein an inner space is formed by the top plate, the bottom plate, and the sidewalls;

a plurality of battery cells existing in the inner space of the module case; and

a resin layer formed by curing the resin composition according to claim 1 and in contact with the plurality of battery cells.

13. A battery pack comprising one or more battery modules according to claim 12 .

14. An automobile comprising the battery module according to claim 12 .

15. A method of manufacturing a battery module, comprising injecting the resin composition according to claim 1 into a module case; housing a battery cell in the module case, and curing the resin composition to form the resin layer.

16. The method of manufacturing a battery module according to claim 15 , wherein the curing of the resin composition is performed by holding the resin composition at room temperature or heating at a temperature in a range of about 30° C. to 50° C. for a predetermined time.