Cellulose fine fiber composition, aqueous dispersion of cellulose fine fiber, polymer composition, molded article and method for producing cellulose fine fiber composition

An aqueous dispersion of cellulose fine fiber, comprising cellulose fine fiber, one or more salts selected from a metal salt and an ammonium salt, and water, wherein

• the cellulose fine fiber has an average fiber width of 1 nm or more and 1,000 nm or less,
• the cellulose fine fiber has a sulfuric acid ester group represented by the following general formula (1),
• the cellulose fine fiber has an amount of sulfur derived from the sulfuric acid ester group of 0.3 mmol/g or more and 3.0 mmol/g or less introduced into the cellulose fine fiber,
• the aqueous dispersion of cellulose fine fiber comprises 0.002 part by mass or more and 10 parts by mass or less of the salt based on 100 parts by mass of the cellulose fine fiber and
• the aqueous dispersion of cellulose fine fiber comprises 10 parts by mass or more of water based on 1 part by mass of the total amount of the cellulose fine fiber and the salts:
• (in the general formula (1), n is an integer of 1 or more and 3 or less, Mn+ is an n-valent cation, and the wavy line indicates a bonding site with another atom).

A polymer composition comprising cellulose fine fiber, one or more salts selected from a metal salt and an ammonium salt and a polymer, wherein

• the cellulose fine fiber has an average fiber width of 1 nm or more and 1,000 nm or less,
• the cellulose fine fiber has a sulfuric acid ester group represented by the following general formula (1),
• the cellulose fine fiber has an amount of sulfur derived from the sulfuric acid ester group of 0.3 mmol/g or more and 3.0 mmol/g or less introduced into the cellulose fine fiber, and
• the polymer composition comprises 0.002 part by mass or more and 10 parts by mass or less of the salt based on 100 parts by mass of the cellulose fine fiber:
• (in the general formula (1), n is an integer of 1 or more and 3 or less, Mn+ is an n-valent cation, and the wavy line indicates a bonding site with another atom).