Acetalization product of ethylenevinyl alcohol copolymer, composition containing said acetalization product, and barrier material

An acetalization product of ethylenevinyl alcohol copolymer, comprising:

• an ethylene unit at from 20% to 80% by mole;
• and
• a vinyl alcohol unit at from 4% to 76% by mole,
• with reference to all monomeric units constituting the acetalization product,
• wherein
• the acetalization product has a degree of acetalization of from 3% to 80% by mole;
• the acetalization product satisfies Formula (1) and Formula (2) below:
• 0.71
• ≤
• W
• 0.05
• h
• /
• 2
• ⁢
• f
• ≤
• 1.09
• (
• 1
• )
• where W0.05h/2f represents a symmetry factor determined by reversed-phase partition gradient high-performance liquid chromatography analysis using a water-ethanol eluant in accordance with JIS K 0124:
• 2011,
• 1.2
• ≤
• Tm
• /
• Tg
• ≤
• 1.35
• (
• 2
• )
• where Tm and Tg represent a melting peak temperature (Kelvin) and a midpoint glass transition temperature (Kelvin), respectively, measured in accordance with JIS K7121:
• 2012;
• and
• the acetalization product has an oxygen permeation rate of 150 cc·20 μm/m2·day·atm or less at 20° C. and 65% RH.