Method of treating substrate

1. A method of treating a substrate, comprising applying a soil resistant agent to the substrate,

wherein the soil resistant agent comprises:

(1) a fluorine-free copolymer comprising:

(a) a repeating unit formed from an acrylic monomer having a hydrocarbon group containing 7 to 40 carbon atoms, and

(b) a repeating unit formed from acrylic monomer having a hydrophilic group, and

(2) water or a mixture of water and an organic solvent dispersing the fluorine-free copolymer (1), and

wherein the substrate is a textile formed from cotton, wool or a synthetic fiber.

2. The method according to claim 1 , wherein the hydrocarbon group-containing acrylic monomer (a) is a monomer represented by the formula:

CH 2 ═C(—X 1 )—C(═O)—Y 1 (R 1 ) k

wherein R 1 each is independently a hydrocarbon group having 7 to 40 carbon atoms,

X 1 is a hydrogen atom, a monovalent organic group or a halogen atom excluding a fluorine atom,

Y 1 is a group consisting of at least one selected from —O—, —C(═O)—, —S(═O) 2 — and —NH—, Y 1 may further include at least one selected from a divalent to tetravalent hydrocarbon group having 1 carbon atom and —C 6 H 4 —, and

k is an integer of 1 to 3.

3. The method according to claim 1 , wherein the hydrocarbon group-containing acrylic monomer (a) is:

(a1) an acrylic monomer represented by the formula:

CH 2 ═C(—X 4 )—C(═O)—Y 2 —R 2

wherein R 2 is a hydrocarbon group having 7 to 40 carbon atoms,

X 4 is a hydrogen atom, a monovalent organic group or a halogen atom excluding a fluorine atom, and

Y 2 is —O— or —NH—, and/or

(a2) an acrylic monomer represented by the formula:

CH 2 ═C(—X 5 )—C(═O)—Y 3 —Z(—Y 4 —R 3 ) n

wherein R 3 each is independently a hydrocarbon group having 7 to 40 carbon atoms,

X 5 is a hydrogen atom, a monovalent organic group or a halogen atom excluding a fluorine atom,

Y 3 is —O— or —NH—,

Y 4 each is independently a direct bond, or a group consisting of at least one selected from, —O—, —C(═O)—, —S(═O) 2 — and —NH—, and

Z is a direct bond, or a divalent or trivalent group having 1 to 5 carbon atoms, and

n is 1 or 2.

4. The method according to claim 1 , wherein, in the hydrocarbon group-containing acrylic monomer (a), the hydrocarbon group has 18 to 40 carbon atoms.

5. The method according to claim 1 , wherein the hydrophilic group-containing acrylic monomer (b) is represented by the formulas:

CH 2 ═CX 2 C(═O)—O—(RO) n —X 3   (b1)

and/or

CH 2 ═CX 2 C(═O)—O—(RO) n —C(═O)CX 2 ═CH 2   (b2)

wherein X 2 is a hydrogen atom or a methyl group,

X 3 is a hydrogen atom or an unsaturated or saturated hydrocarbon group having 1 to 22 carbon atoms,

R each is independently an alkylene group having 2 to 6 carbon atoms, and

n is an integer of 1 to 90.

6. The method according to claim 1 , wherein the fluorine-free copolymer (1) further comprises (c) a repeating unit formed from a monomer having an ion-donating group, other than the monomers (a) and (b).

7. The method according to claim 1 , wherein the monomer (c) is a monomer wherein a homopolymer thereof has a glass transition point or melting point of at least 70° C.

8. The method according to claim 6 , wherein the amount of the repeating unit formed from the hydrocarbon group-containing acrylic monomer (a) is 30 to 97% by weight, based on the copolymer,

the amount of the repeating unit formed from the hydrophilic group-containing acrylic monomer (b) is 3 to 70% by weight, based on the total of the acrylic monomers (a) and (b), and

the amount of monomer (c) is 0.1 to 60% by weight, based on the copolymer.

9. The method according to claim 1 , wherein the fluorine-free copolymer (1) is a random copolymer.

10. The method according to claim 1 , wherein the soil resistant agent further comprises:

(3) an acrylic blender having a repeating unit formed from a monomer in which a homopolymer of the monomer has a glass transition point or melting point of at least 70° C.

11. The method according to claim 10 , wherein the acrylic blender is a homopolymer or copolymer of at least one monomer selected from the group consisting of amidoethyl stearate acrylate (melting point: 92° C.), methyl methacrylate (glass transition point: 105° C.), acrylic acid (glass transition point: 106° C.) and methacrylic acid (glass transition point: 185° C.).

12. The method according to claim 10 , wherein, in the polymer of the acrylic blender, the amount of the monomer, in which a homopolymer of the monomer has a glass transition point or melting point of at least 70° C., is at least 30 wt %, based on the polymer.

13. The method according to claim 1 , wherein the substrate which is a textile formed from cotton, wool or a synthetic fiber is a carpet.

14. The method according to claim 13 , which comprises imparting water-repellency and soiling resistance to the carpet formed from cotton, wool or a synthetic fiber.