A yarn for reinforcing composite material includes carbon nanotubes. The yarn has also been treated to promote interaction with a resinous matrix.

A yarn for reinforcing composite material includes carbon nanotubes. The yarn has also been treated to promote interaction with a resinous matrix.

An environment-friendly impregnation solution includes in percentage by weight: 1-15% of blocked isocyanate, 0.5-10% of special amino resin, 10-50% of rubber latex, 1-5% of auxiliaries, and the balance of water, wherein the sum of the weight percentage of each component is 100%. A method for preparing the environment-friendly impregnation solution includes adding blocked isocyanate and auxiliary A into water and stirring uniformly to obtain Composition 1; adding auxiliary B into Composition 1 and stirring uniformly to obtain Composition 2; adding special amino resin into Composition 2 and stirring uniformly, then subjecting the same to grinding to obtain Composition 3; adding rubber latex into Composition 3 and stirring uniformly to obtain the environment-friendly impregnation solution, followed by packaging. The impregnation solution of the invention does not contain toxic and harmful substances such as formaldehyde and resorcinol, and the preparation method thereof is simple.