Coating agent and medical instrument surface-treated with said coating agent

A coating agent comprising:

• (1) a polyorganosiloxane represented by the following general formula (1):
• wherein each R1 and each R2 independently represents a monovalent hydrocarbon group,
• each R1′ independently represents a monovalent hydrocarbon group or a hydroxy group (—OH group), and
• m is an integer of 3,500 to 10,000
• (2) a polydiorganosiloxane represented by the following general formula (2):
• wherein R1 represents a monovalent hydrocarbon group,
• wherein each R3 and each R4 independently represents a monovalent hydrocarbon group, and
• n is an integer of 30 to 50;
• and
• (3) an amino group-containing polyorganosiloxane or (4) a hydroxy group-containing polyorganosiloxane,
• wherein the amino group-containing polyorganosiloxane contains at least one amino group per molecule represented by the following general formula (3):
• wherein each R5 independently represents a monovalent hydrocarbon group or an —OR8 group, wherein each R8 independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 4 carbon atoms,
• each R6 and each R7 independently represents a monovalent hydrocarbon group,
• each A independently represents an amino group-containing group,
• p:q=5:1 to 100:1, and
• q is an integer in a range of 1 to 100;
• wherein the hydroxy group-containing polyorganosiloxane is represented by the following general formula (4):
• wherein each R9 and each R9′ independently represents a monovalent hydrocarbon group or a hydroxy group (—OH), provided that at least one R9 is a hydroxy group (—OH) and at least one R9′ is a hydroxy group (—OH),
• each R10 independently represents a monovalent hydrocarbon group, and
• r is an integer of 1,000 to 30,000.