Fluorocopolymer and water and oil proofing composition, and processes for their production

A fluorocopolymer comprising from 40 to 98 mass % of polymerized units (a′) based on the following monomer (a), from 1 to 50 mass % of polymerized units (b′) based on the following monomer (b) and from 1 to 10 mass % of polymerized units (c′) based on the following monomer (c):

• Monomer (a):
• a compound represented by (Z—Y)nX, wherein Z is a C1-6 perfluoroalkyl group or a monovalent group represented by CmF2m+1O(CFWCF2O)dCFK— (wherein m is an integer of from 1 to 6, d is an integer of from 1 to 4, and each of W and K which are independent of each other, is a fluorine atom or a trifluoromethyl group), Y is a single bond or a bivalent organic group containing no fluorine atom, n is 1 or 2, provided that when n is 1, X is —CR═CH2, —COOCR═CH2, —OCOCR═CH2, —OCH2-φ-CR═CH2 or —OCH═CH2, and when n is 2, X is —CH[—(CH2)pCR═CH2]—, —CH[—(CH2)pCOOCR═CH2]—, —CH [—CH2)pOCOCR═CH2]— or —OCOCH═CHCOO—, R is a hydrogen atom, a methyl group or a halogen atom, φ is a phenylene group, p is an integer of from 0 to 4, and when n is 2, two (Z—Y) present in one molecule may be the same or different from each other;
• Monomer (b):
• a compound represented by CH2═CR1-G-(R2O)q—R3, wherein R1 is a hydrogen atom or a methyl group, R2 is a C2-4 alkylene group, or a C2-3 alkylene group having some or all of its hydrogen atoms substituted by hydroxyl groups, q is an integer of from 1 to 10, G is —COO(CH2)r— or —COO(CH2)t—NHCOO— (wherein r is an integer of from 0 to 4, and t is an integer of from 1 to 4), and R3 is a hydrogen atom, a methyl group, an acryloyl group, a methacryloyl group or an allyl group;
• Monomer (c):
• a compound represented by CH2═C(COOH)-Q-COOH, wherein Q is a C1-4 alkylene group, or a C2-3 alkylene group having some or all of its hydrogen atoms substituted by hydroxyl groups, and in the monomer (c), some or all of the carboxyl groups may form at least one salt selected from an ammonium salt and an organic amine salt.