Antireflection film, polarizing plate, and image display device

1. An antireflection film comprising a support and a low refractive index layer prepared by coating a coating composition containing the following components:

(A) a fluorine-containing polymer having, a principal chain which is made of only carbon atoms and the fluorine-containing polymer contains at least one fluorine-containing vinyl monomer polymerization unit and at least one hydroxyl group-containing vinyl monomer polymerization unit, wherein a content of the hydroxyl group-containing vinyl monomer polymerization unit exceeds 20% by mole, provided that the polymer does not have a polysiloxane structure in the principal chain;

(B) a crosslinking agent that reacts with a hydroxyl group; and

(C) a compound containing two or more (meth)acryloyl groups in one molecule thereof,

wherein the fluorine-containing polymer contains at least one polymerization unit having a graft site containing, in a side chain thereof, a polysiloxane repeating unit represented by the following formula (1):

wherein R 1 and R 2 may be the same or different and each represents an alkyl group or an aryl group; and p represents an integer of from 10 to 500; and

wherein the coating composition further contains at least one salt comprising an organic base having a pKa of from 5.0 to 10.5 in terms of a conjugated acid thereof and an acid.

2. An antireflection film comprising a support and a low refractive index layer prepared by coating a coating composition containing the following components:

(A) a fluorine-containing polymer having, a principal chain which is made of only carbon atoms and the fluorine-containing polymer contains at least one fluorine-containing vinyl monomer polymerization unit and at least one hydroxyl group-containing vinyl monomer polymerization unit, wherein a content of the hydroxyl group-containing vinyl monomer polymerization unit exceeds 20% by mole, provided that the polymer does not have a polysiloxane structure in the principal chain;

(B) a crosslinking agent that reacts with a hydroxyl group; and

(D) an organosilane compound or a composition containing at least one of a hydrolyzate of the organosilane compound and a partial condensate of the organosilane compound,

wherein the fluorine-containing polymer contains at least one polymerization unit having a graft site containing, in a side chain thereof, a polysiloxane repeating unit represented by the following formula (1):

wherein R 1 and R 2 may be the same or different and each represents an alkyl group or an aryl group; and p represents an integer of from 10 to 500; and

wherein the coating composition further contains at least one salt comprising an organic base having a pKa of from 5.0 to 10.5 in terms of a conjugated acid thereof and an acid.

3. An antireflection film comprising a support and a low refractive index layer prepared by coating a coating composition containing the following components:

(A) a fluorine-containing polymer having, a principal chain which is made of only carbon atoms and the fluorine-containing polymer contains at least one fluorine-containing vinyl monomer polymerization unit and at least one hydroxyl group-containing vinyl monomer polymerization unit, wherein a content of the hydroxyl group-containing vinyl monomer polymerization unit exceeds 20% by mole, provided that the polymer does not have a polysiloxane structure in the principal chain;

(B) a crosslinking agent that reacts with a hydroxyl group; and

(E) an inorganic particle having a particle size of 1 nm or more and not more than 100 nm,

wherein the fluorine-containing polymer contains at least one polymerization unit having a graft site containing, in a side chain thereof, a polysiloxane repeating unit represented by the following formula (1):

wherein R 1 and R 2 may be the same or different and each represents an alkyl group or an aryl group; and p represents an integer of from 10 to 500; and

wherein the coating composition further contains at least one salt comprising an organic base having a pKa of from 5.0 to 10.5 in terms of a conjugated acid thereof and an acid.

4. The antireflection film as claimed in claim 1 , wherein the coating composition further contains (E) an inorganic particle having a particle size of 1 nm or more and not more than 100 nm.

5. The antireflection film as claimed in claim 2 , wherein the coating composition further contains (E) an inorganic particle having a particle size of 1 nm or more and not more than 100 nm.

6. The antireflection film as claimed in claim 1 , wherein the coating composition further contains (F) a polysiloxane compound having a hydroxyl group or a function group that reacts with a hydroxyl group to form binding.

7. The antireflection film as claimed in claim 2 , wherein the coating composition further contains (F) a polysiloxane compound having a hydroxyl group or a function group that reacts with a hydroxyl group to form binding.

8. The antireflection film as claimed in claim 3 , wherein the coating composition further contains (F) a polysiloxane compound having a hydroxyl group or a function group that reacts with a hydroxyl group to form binding.

9. The antireflection film as claimed in claim 1 , wherein the coating composition further contains at least one salt comprising a nitrogen-containing organic base having a boiling point of 35° C. or higher and not higher than 85° C. and an acid.

10. The antireflection film as claimed in claim 2 , wherein the coating composition further contains at least one salt comprising a nitrogen-containing organic base having a boiling point of 35° C. or higher and not higher than 85° C. and an acid.

11. The antireflection film as claimed in claim 3 , wherein the coating composition further contains at least one salt comprising a nitrogen-containing organic base having a boiling point of 35° C. or higher and not higher than 85° C. and an acid.

12. The antireflection film as claimed in claim 3 , wherein the inorganic particle is a hollow silica particle.

13. The antireflection film as claimed in claim 1 , further comprising at least one layer having a refractive index higher than that of the low refractive index layer between the support and the low refractive index layer, wherein the at least one layer contains an organosilane compound or a composition containing at least one of a hydrolyzate of the organosilane compound and a partial condensate of the organosilane compound.

14. The antireflection film as claimed in claim 2 , further comprising at least one layer having a refractive index higher than that of the low refractive index layer between the support and the low refractive index layer, wherein the at least one layer contains an organosilane compound or a composition containing at least one of a hydrolyzate of the organosilane compound and a partial condensate of the organosilane compound.

15. The antireflection film as claimed in claim 3 , further comprising at least one layer having a refractive index higher than that of the low refractive index layer between the support and the low refractive index layer, wherein the at least one layer contains an organosilane compound or a composition containing at least one of a hydrolyzate of the organosilane compound and a partial condensate of the organosilane compound.

16. A polarizing plate comprising a polarizing film and the antireflection film as claimed in claim 1 , wherein the antireflection film is provided as one of two protective films for a polarizing film in the polarizing plate.

17. A polarizing plate comprising a polarizing film and the antireflection film as claimed in claim 2 , wherein the antireflection film is provided as one of two protective films for a polarizing film in the polarizing plate.

18. A polarizing plate comprising a polarizing film and the antireflection film as claimed in claim 3 , wherein the antireflection film is provided as one of two protective films for a polarizing film in the polarizing plate.

19. An image display device comprising the antireflection film as claimed in claim 1 , wherein the antireflection film is provided at an outermost surface of a display.

20. An image display device comprising the antireflection film as claimed in claim 2 , wherein the antireflection film is provided at an outermost surface of a display.

21. An image display device comprising the antireflection film as claimed in claim 3 , wherein the antireflection film is provided at an outermost surface of a display.

22. The antireflection film as claimed in claim 1 , wherein the salt is a compound that generates an acid by heating.

23. The antireflection film as claimed in claim 2 , wherein the salt is a compound that generates an acid by heating.

24. The antireflection film as claimed in claim 3 , wherein the salt is a compound that generates an acid by heating.