Antifouling composition, process for its production and article treated therewith

A process for producing an antifouling composition, which comprises:

• subjecting monomer components (Z) comprising from 30 to 59 mass % of a monomer (a) and from 40 to 70 mass % of a monomer (b) to solution polymerization in an organic solvent containing a volatile organic solvent having a boiling point of at most 100° C. in the presence of a surfactant (c) to form a fluorocopolymer (A), and
• volatilizing the volatile organic solvent after the solution polymerization and adding an aqueous medium to form an aqueous dispersion,
• wherein the surfactant (c) comprises at least one compound represented by formula (I):
• wherein each of x1 and x2 is an integer of at least 1, and (x1+x2) is at least 2 and at most 30;
• and the average of (x1+x2) per one molecule in the surfactant (c) is at least 6:
• wherein the monomer (a) is a monomer having a polyfluoroalkyl group in which the number of carbon atoms to which fluorine atoms are bonded is from 4 to 6 provided that the polyfluoroalkyl group may contain an etheric oxygen atom;
• and
• wherein the monomer (b) comprises a monomer (b3) represented by formula (4):
• CH2═CR6-G2-(C2H4O)q2—(C4H8O)q3—R7 (4)
• wherein each of R6 and R7 which are independent of each other, is a hydrogen atom or a methyl group, q2 is an integer of 0 or from 1 to 50, q3 is an integer of from 1 to 50, G2 is —COO(CH2)r2— or —COO(CH2)t2—NHCOO—, wherein r2 is an integer of from 0 to 4, and t2 is an integer of from 1 to 4.

An antifouling composition comprising:

• 100 parts by mass of a fluorocopolymer (A) comprising from 30 to 59 mass % of polymerized units of a monomer (a) and from 40 to 70 mass % of polymerized units of a monomer (b), and
• from 10 to 30 parts by mass of a surfactant (c), wherein the surfactant (c) comprises at least one compound represented by formula (1):
• wherein each of x1 and x2 is an integer of at least 1, and (x1+x2) is at least 2 and at most 30, and the average of (x1+x2) per one molecule in the surfactant (c) is at least 6;
• wherein the monomer (a) is a monomer having a polyfluoroalkyl group in which the number of carbon atoms to which fluorine atoms are bonded is from 4 to 6 provided that the polyfluoroalkyl group may comprise an etheric oxygen atom;
• wherein the monomer (b) consists of a monomer (b1) and a monomer (b3),
• wherein the monomer (b1) is represented by formula (1):
• CH2═CR1-G1-(C2H4O)q1—R2 (1)
• wherein R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, a methyl group, an acryloyl group or a methacryloyl group, q1 is an integer of from 1 to 50, and G1 is —COO(CH2)r1— or —COO(CH2)t1NHCOO— wherein r1 is an integer of from 0 to 4, and t1 is an integer of from 1 to 4, and
• wherein the monomer (b3) is represented by formula (4):
• CH2═CR6-G2-(C2H4O)q2—(C4H8O)q3—R7 (4)
• wherein each of R6 and R7 which are independent of each other, is a hydrogen atom or a methyl group, q2 is an integer of 0 or from 1 to 50, q3 is an integer of from 1 to 50, G2 is —COO(CH2)r2— or —COO(CH2)t2—NHCOO—, wherein r2 is an integer of from 0 to 4, and t2 is an integer of from 1 to 4.