Wet lubricant surface coating having excellent durability, method for surface coating, and a medical device having the surface coating

1. A surface coating having wet-lubricity, comprising:

an inner layer on the surface that is:

(A) a urethane polymer layer which includes (a) 40 to 80% by weight of at least one component selected from an aromatic diisocyanate, an aliphatic diisocyanate and an alicyclic diisocyanate and (b) 20 to 60% by weight of a polyol having at least trifunctionality for forming the urethane polymer layer, said polyol being selected from the group consisting of branched polyol derivatives of polyester polyols, polyether polyols (poly(oxypropylene ether) polyol and poly(oxyethylene-propylene ether) polyol), and acrylic polyol; castor oil and its derivatives; glycerol, trimethylol propane, trimethylol ethane, 1,2,6-hexane triol, pentaerythritol, sorbitol, and mannito, and

an outer layer formed on said inner layer that is:

(B) a hydrophilic polymer layer which is provided as an outer layer for the urethane polymer layer and which includes a polyalkylene glycol and/or a monomethoxypolyalkylene glycol, such that said surface coating has both wet lubricity and durability.

2. The surface coating having wet-lubricity according to claim 1 , wherein the polyalkylene glycol and/or monomethoxypolyalkylene glycol constituting the hydrophilic polymer layer (B) is a linear polyalkylene glycol and/or monomethoxypolyalkylene glycol having a weight average molecular weight of 1000 to 100000; or a polyfunctional polyalkylene glycol derivative satisfying the formula:

50000× n >weight average molecular weight>500× n   (formula)

wherein n is the number of hydroxyl terminal group(s).

3. A medical device having the surface coating according to claim 1 or 2 .

4. A method for coating which provides a surface coating comprising the steps of

forming an inner first layer by coating a mixed solution including an isocyanate compound and a polyol having at least trifunctionality on a surface to form a urethane polymer layer;

coating a solution including a polyalkylene glycol and/or a monomethoxypolyalkylene glycol; and then

forming a hydrophilic polymer layer, as a second layer on said first layer, which is provided as an outer layer for the urethane polymer layer, such that said surface coating has both wet lubricity and durability.

5. A surface coating produced by the method for coating according to claim 4 .

6. A medical device having the surface coating according to claim 5 .