Water/oil repellent composition, method for its production and article

1. A method for producing a water and/or oil repellent composition, which comprises polymerizing monomer components comprising the following monomer (a) and the following monomer (b) in an aqueous medium in the presence of a surfactant and a polymerization initiator to produce an emulsion in which fine particles of a copolymer (X) having a mass average molecular weight of at least 60,000 are emulsified in the aqueous medium, wherein

the proportion of the monomer (a) in the monomer components is from 60 to 95 mass % based on the monomer components (100 mass %):

monomer (a): a compound represented by the following formula (1):

(Z—Y) n X  1

wherein Z is a C 1 - 6 polyfluoroalkyl group or a group represented by the following formula (2), Y is a bivalent organic group having no fluorine atom, or a single bond, n is 1 or 2, and X is, when n is 1, any one of the groups represented by the following formulae (3-1) to (3-5) and, when n is 2, any one of the groups represented by the following formulae (4-1) to (4-4):

C i F 2i+1 O(CFX 1 CF 2 O) j CFX 2 —  (2)

wherein i is an integer of from 1 to 6, j is an integer of from 0 to 10, and each of X 1 and X 2 is a fluorine atom or a trifluoromethyl group;

—CR═CH 2   (3-1)

—C(O)OCR═CH 2   (3-2)

—OC(O)CR═CH 2   (3-3)

—OCH 2 -φ-CR═CH 2   (3-4)

—OCH═CH 2   (3-5)

wherein R is a hydrogen atom, a methyl group or a halogen atom, and φ is a phenylene group;

—CH[—(CH 2 ) m CR═CH 2 ]—  (4-1)

—CH[—(CH 2 ) m C(O)OCR═CH 2 ]—  (4-2)

—CH[—(CH 2 ) m OC(O)CR═CH 2 ]—  (4-3)

—OC(O)CH═CHC(O)—  (4-4)

where R is a hydrogen atom, a methyl group or a halogen atom, and m is an integer of from 0 to 4;

monomer (b): vinyl chloride, and

wherein, with the emulsion obtained by polymerization, an emulsion containing fine particles of copolymer (Y) having a zeta potential higher by from 10 to 60 mV than the zeta potential of the copolymer (X) and having a zeta potential of from 20 to 70 mV, is blended in a proportion of from 5 to 50 mass % based on the total amount of the copolymer (X) and the copolymer (Y)

wherein copolymer (Y) is a copolymer which has structural units based on the monomer (a) and which is the same as or different from the copolymer (X), of which the proportion of the structural units based on the monomer (a) is from 60 to 95 mass % based on the structural units (100 mass %) based on all the monomers constituting the copolymer.

2. The production method according to claim 1 , wherein the monomer components further include the following monomer (c):

monomer (c): a monomer having no polyfluoroalkyl group and having a crosslinkable functional group.

3. The production method according to claim 1 , wherein the monomer components further include the following monomer (d):

monomer (d): an alkyl (meth)acrylate having no polyfluoroalkyl group and having a C 18-30 alkyl group.

4. The production method according to claim 1 , wherein the zeta potential of the copolymer (X) in the emulsion obtained by polymerization is from 10 to 40 mV.

5. The production method according to claim 1 , wherein the emulsion containing fine particles of the copolymer (Y) is an emulsion obtained by polymerizing monomer components comprising the monomer (a) and the monomer (b) in an aqueous medium in the presence of a surfactant and a polymerization initiator.

6. The production method according to claim 1 , wherein the emulsion containing fine particles of the copolymer (X) is blended and diluted with an aqueous medium.