Treatment agent and ink set

1. A treatment agent applicable to a recording surface of a recording medium which is recording paper or fabric, the treatment agent comprising:

a non-cationic sizing agent; and

at least one cationic substance which is selected from the group consisting of: a cationic polymer capable of forming a flexible film in a case that the cationic polymer is dried, and a cationic surfactant,

wherein the cationic polymer is a cationic polymer having a urethane structure or a water-soluble polymer having diallylamines represented by the following formula (2) as a constituent of the water-soluble polymer:

wherein in the formula (2), R 2 and R 3 are each a substituted or non-substituted, straight-chain or branched-chain alkyl group, and the R 2 and the R 3 are identical with each other or different from each other;

X − is an anion, and

wherein a number of the constituent represented by the formula (2) in the water-soluble polymer is in a range of 5 to 1000.

2. The treatment agent according to claim 1 , wherein a blending amount of the cationic substance in an entire amount of the treatment agent is in a range of 1% by weight to 15% by weight.

3. The treatment agent according to claim 1 , wherein a blending amount of the cationic substance in an entire amount of the treatment agent is in a range of 10% by weight to 15% by weight.

4. The treatment agent according to claim 1 , wherein the cationic polymer is the cationic polymer having a urethane structure.

5. The treatment agent according to claim 4 , wherein a ratio of the urethane structure is not less than 10% by weight in the cationic polymer having the urethane structure.

6. The treatment agent according to claim 4 , wherein the treatment agent contains an emulsion of the cationic polymer having the urethane structure.

7. The treatment agent according to claim 4 , wherein the cationic polymer having the urethane structure further has at least one of an acrylic structure and a styrene structure.

8. The treatment agent according to claim 7 , wherein the cationic polymer having the urethane structure has the acrylic structure.

9. The treatment agent according to claim 4 , wherein the urethane structure is obtained by:

an aliphatic isocyanate; and

a polyether polyol or polyester polyol.

10. The treatment agent according to claim 1 , wherein the cationic polymer is the water-soluble polymer having diallylamines represented by the formula (2) as a constituent of the water-soluble polymer.

11. The treatment agent according to claim 10 , wherein the R 2 and the R 3 in the formula (2) are each a methyl group; and

the X − is a methylsulfate ion or a chloride ion.

12. The treatment agent according to claim 1 , wherein a blending amount of the non-cationic sizing agent in an entire amount of the treatment agent is in a range of 0.2% by weight to 10% by weight.

13. The treatment agent according to claim 1 , wherein a blending amount of the non-cationic sizing agent in an entire amount of the treatment agent is in a range of 1% by weight to 5% by weight.

14. The treatment agent according to claim 1 , wherein the non-cationic sizing agent is at least one selected from the group consisting of: sodium alginate, pregelatinized starch and carboxymethyl cellulose.

15. The treatment agent according to claim 1 , wherein a ratio (X/Y) of a blending amount (X: % by weight) of the cationic substance to a blending amount (Y: % by weigh) of the non-cationic sizing agent is in a range of 3.3 to 5.

16. The treatment agent according to claim 1 , wherein in a case that the recording medium is the recording paper, an application amount of the treatment agent per unit area of the recording surface is not more than 1.3 mg/cm 2 ; and

in a case that the recording medium is the fabric, the application amount of the treatment agent per the unit area of the recording surface is in a range of 5.0 mg/cm 2 to 48 mg/cm 2 .

17. A treatment agent applicable to a recording surface of a recording medium which is recording paper or fabric, the treatment agent comprising:

a non-cationic sizing agent; and

at least one cationic substance which is selected from the group consisting of: a cationic polymer capable of forming a flexible film in a case that the cationic polymer is dried, a cationic surfactant, a polyvalent metal salt and a polyvalent metal ion,

wherein in a case that the recording medium is the fabric, the non-cationic sizing agent applied to the recording surface is washed by water.

18. An ink set comprising:

a water-based ink for ink-jet recording containing an anionic coloring agent and water; and

the treatment agent as defined in claim 1 .