An elastomer is provided, which is a product of reacting C4-12 lactam, poly(C2-4 alkylene glycol), C4-12 diacid, and multi-ester aliphatic monomer. The C4-12 lactam and the poly(C2-4 alkylene glycol) have a weight ratio of 20:80 to 80:20. The total weight of the C4-12 lactam and the poly(C2-4 alkylene glycol) and the weight of the C4-12 diacid have a ratio of 100:0.5 to 100:10. The total weight of the C4-12 lactam and the poly(C2-4 alkylene glycol) and the weight of the multi-ester aliphatic monomer have a ratio of 100:0.01 to 100:5.