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

Active Publication Date: 2009-06-10
MITSUBISHI CHEM CORP
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Problems solved by technology

If EVOH adheres to the inner wall of the condenser, the condensation efficiency will decrease, and the water replacement of the EVOH solution cannot be continuously performed due to the clogging of the pipe.

Method used

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

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Embodiment

[0044] Hereinafter, an Example and a comparative example are given and this embodiment is demonstrated more concretely, However, Unless the summary is exceeded, this invention is not limited to description of a following example.

[0045] (Example) A methanol solution (EVOH 30% by mass) containing EVOH with an ethylene content of 44 mol% and a degree of saponification of 99.7 mol% is supplied (1000 parts by mass / hour) to the second stage tray from the top of a 10-layer plate column, Water vapor was supplied (100 parts by mass / hour) from the lowermost tray. In addition, water was supplied to the uppermost tray. The temperature in the tower was 90° C. (column top), and the pressure was 0.1 MPaG (column top). The methanol vapor and water vapor distilled off from the top of the tower are condensed in a condenser and recovered as methanol aqueous solution. An EVOH aqueous composition (EVOH 40% by mass, methanol / water=80 / 20) was withdrawn from the bottom of the column. After the ...

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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).

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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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J3/07
CPCC08J2323/08C08J3/07
Inventor 西山和宏
Owner MITSUBISHI CHEM CORP
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