Method for producing water-containing composition of ethylene-vinyl alcohol copolymer

A vinyl alcohol copolymer and a production method technology are applied in the field of EVOH water-containing composition production, which can solve problems such as catheter blockage, inability to continuously perform water replacement of EVOH solution, and reduction in condensation efficiency, and achieve inhibition of catheter blockage and condensation efficiency. The effect of reducing and suppressing the decrease in productivity
CN101454380AActive Publication Date: 2009-06-10MITSUBISHI CHEM CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
MITSUBISHI CHEM CORP
Publication Date
2009-06-10

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Abstract

An ethylene-vinyl alcohol copolymer (EVOH) solution is introduced into a tower vessel (1) from a first inlet (2) provided at an upper portion of the tower vessel (1). Water vapor is introduced into the tower vessel (1) from a second inlet (3) provided at a lower portion of the vessel (1). The EVOH solution moves downward in the vessel (1), while the water vapor moves upward. The EVOH solution is kept in counter-flow contact with the water vapor. Water is supplied from a water supplying portion (5) located between the first inlet (2) and a tower top (4), whereby a water layer is formed above the first inlet (2). A water / methanol vapor mixture is extracted from the tower top (4) and condensed in a condenser (6) to be thereby recovered in the form of a methanol aqueous solution. Droplets of the EVOH solution contained in the water / methanol vapor mixture are trapped in the water layer formed above the first inlet (2) and, therefore, are less liable to be introduced into the condenser (6). This suppresses extraction of the droplets of the EVOH solution together with the vapor to the outside of the tower vessel (1) during replacement of the EVOH solution with water in the tower vessel (1).
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Description

technical field

[0001] The present invention relates to a method for producing an EVOH aqueous composition, which has the following steps: in a tower container, the ethylene-vinyl alcohol copolymer (hereinafter also referred to as EVOH) solution is in convective contact with water vapor, and the aforementioned solution At least a part of the solvent in is replaced with water. Background technique

[0002] EVOH has excellent oxygen barrier properties and is widely used as a raw material for various packaging materials and bottles. EVOH is generally produced by copolymerizing vinyl acetate and ethylene, and saponifying the obtained ethylene-vinyl acetate copolymer in the presence of an alkali catalyst using methanol as a solvent. EVOH, which is a saponified product, is obtained as a methanol solution under heating and pressure. The methanol solution of EVOH can be stably handled as a solution even at normal temperature and pressure by substituting a part of the methanol with...

Claims

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