Cellulose acylate film, retardation film, polarizer and liquid crystal display device

A retardation film comprising a cellulose acylate film, wherein the cellulose acylate film comprises a cellulose acylate resin having a degree of acyl substitution satisfying all the following formulae (i), (ii) and (iii) and a compound capable of forming a hydrogen bond satisfying all the following conditions (A), (B) and (C):

• (A) the compound has both a hydrogen bond donor moiety and a hydrogen bond acceptor moiety in the molecule,
• (B) the value obtained by dividing the molecular weight of the compound by the total of the number of the hydrogen bond donor moiety and the number of the hydrogen bond acceptor moiety is from 30 to 65,
• (C) the number of aromatic ring structures is from 1 to 3,
• 0.5≦A+B≦2.7, (i)
• 0.0≦A≦2.5, and (ii)
• 0.1≦B≦2.0, (iii)
• where, in the formulae (i), (ii) and (iii), A means the degree of substitution with an acetyl group, and B means a total of the degree of substitution with a propionyl group and the degree of substitution with a butyryl group.

A polarizer comprising a cellulose acylate film, wherein the cellulose acylate film comprises a cellulose acylate resin having a degree of acyl substitution satisfying all the following formulae (i), (ii) and (iii) and a compound capable of forming a hydrogen bond satisfying all the following conditions (A), (B) and (C):

• (A) the compound has both a hydrogen bond donor moiety and a hydrogen bond acceptor moiety in the molecule,
• (B) the value obtained by dividing the molecular weight of the compound by the total of the number of the hydrogen bond donor moiety and the number of the hydrogen bond acceptor moiety is from 30 to 65,
• (C) the number of aromatic ring structures is from 1 to 3,
• 0.5≦A+B≦2.7, (i)
• 0.0≦A≦2.5, and (ii)
• 0.1≦B≦2.0, (iii)
• where, in the formulae (i), (ii) and (iii), A means the degree of substitution with an acetyl group, and B means a total of the degree of substitution with a propionyl group and the degree of substitution with a butyryl group.

A liquid crystal display device comprising a cellulose acylate film, wherein the cellulose acylate film comprises a cellulose acylate resin having a degree of acyl substitution satisfying all the following formulae (i), (ii) and (iii) and a compound capable of forming a hydrogen bond satisfying all the following conditions (A), (B) and (C):

• (A) the compound has both a hydrogen bond donor moiety and a hydrogen bond acceptor moiety in the molecule,
• (B) the value obtained by dividing the molecular weight of the compound by the total of the number of the hydrogen bond donor moiety and the number of the hydrogen bond acceptor moiety is from 30 to 65,
• (C) the number of aromatic ring structures is from 1 to 3,
• 0.5≦A+B≦2.7, (i)
• 0.0≦A≦2.5, and (ii)
• 0.1≦B≦2.0, (iii)
• where, in the formulae (i), (ii) and (iii), A means the degree of substitution with an acetyl group, and B means a total of the degree of substitution with a propionyl group and the degree of substitution with a butyryl group.