PUNCTURE NEEDLE

PROBLEM TO BE SOLVED: To lower the resistance at the time of piercing and to prevent the resistance from increasing in spite of repetitive piercing by applying a mixture composed of polyorganosiloxane and nonreactive polyorganosiloxane on the outside surface of a needle. SOLUTION: The polyorganosiloxane formed by bringing epoxy group-contg. alkoxysilane into reaction with the amino groups existing at both terminals is synthesized by using the polyorganosiloxane having silanol groups at both terminals. Namely, the amino group-contg. alkoxysilane is brought into reaction with the polyorganosiloxane having the silanol groups at both terminals and the reaction product thereof and the epoxy group-contg. alkoxysilane are brought into reaction. The nonreactive polyorganosiloxane is mixed with the resulted product and the mixture is diluted by a solvent to about 5% non-volatile component. The alkoxy groups are adhered on the surface of the puncture needle by condensation reaction by immersing the needle into a coating consisting of the diluted mixture and resting the needle at room temp. Further, the alkoxy groups form crosslinked bodies with each other.