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Method for preparing vinyl-vinyl-acetic ester copolymer and saponifiable material of copolymer obtained therefrom

A technology of vinyl acetate and copolymers, which is applied in the field of preparation of ethylene-vinyl acetate copolymers, and can solve the problems of extruder load fluctuations, shrinkage fluctuations, pressure differences, etc.

Inactive Publication Date: 2002-05-22
KURARAY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, with the existing method, the load of the extruder tends to fluctuate when the EVOH is melt-extruded, and the stability of the melt extrusion is not necessarily sufficient.
In addition, when EVOH is melt-extruded, pressure differences, neck-in fluctuations, etc. tend to occur, and the melt formability is not necessarily sufficient.
Moreover, with the previous method, coloring or gelation tended to occur in the formed EVOH

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0082] Use and heat conduction area 4m 2 , 10-tube vertical wet-wall multi-tubular heat exchanger connected to a polymerization tank with an inner volume of 750L. In this polymerization tank, vinyl acetate having an acetaldehyde content of 10 ppm and a methyl acetate content of 500 ppm was introduced as a whole through a heat exchanger at a rate of 31 kg / hr. On the other hand, ethylene was supplied at a rate of 6 kg / hr, and the polymerization initiator 2,2'-azobis-(4-methoxy-2,4-dimethylvaleronitrile) (AMV) was supplied as vinyl acetate One-2000th of the amount, that is, at a rate of 15.5 g / hr, the polymerization solvent methanol at a rate of 2.3 kg / hr, were directly introduced into the polymerization tank respectively. In addition, among other materials introduced into the polymerization tank, neither of acetaldehyde and methyl acetate was substantially contained. Therefore, in the polymerization solution, the content ratios of acetaldehyde and methyl acetate relative to th...

Embodiment 2

[0088] Linear low-density polyethylene (density 0.92g / cm 3 , MF1.5g / 10 minutes (190°C, 2160g)) as the two outer layers, the EVOH obtained in Example 1 as the middle layer, between the two outer layers and the middle layer a linear low-density material modified by grafting of maleic anhydride Polyethylene (maleic anhydride modification amount 0.5% by weight, density 0.91g / cm 3 , MFR1.5g / 10min (190°C, 2160g)) as an adhesive layer and formed as an evaluation of 3 types of 5-layer co-extruded films (thickness of each layer; 20μm / 10μm / 15μm / 10μm / 20μm, total thickness 75μm) A film was formed and evaluated by the method described in the method column. At this time, the extrusion temperature of each resin was 220°C. The evaluation results are shown in Table 1. (Example 3)

Embodiment 3

[0089] In Example 1, EVOH pellets were produced and analyzed in the same manner as in Example 1 except that DPMP was not added, and an EVOH single-layer film was prepared and evaluated. The analysis results and evaluation results are shown in Table 1. (Example 4)

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Abstract

The objects of the present invention are (1) improving the stability of melt extrusion, (2) improving the ability of melt molding, (3) reducing the incidence of coloring, (4) reducing the incidence of gel, when preparing the saponification substance of ethylene-vinylacetate copolymer (EVOH). The ethylene and vinylacetate are copolymerized with the polymerization initiator for preparing the ethylene-vinylacetate copolymer containing the 5 to 60% by mole of ethylene. And the fatty alcohol containing below 4 of carbon atoms are used as polymerizing solvent. The contents of acetaldehyde and saturated acetate are respectively below 200 ppm and 10 to 1500 ppm, and polymerizing temperature is 30 to 150 DEG C.

Description

[0001] The technical field of the invention [0002] The present invention relates to a method for producing ethylene-vinyl acetate copolymer (EVA) capable of producing ethylene-vinyl acetate copolymer saponified product (EVOH) with excellent melt extrusion stability, melt formability, and less coloring or gel . Background technique [0003] Previously, EVOH was industrially produced by polymerizing ethylene and vinyl acetate using a polymerization initiator to form EVA and saponifying it. However, with the conventional method, the load of the extruder tends to fluctuate when the EVOH is melt-extruded, and the stability of the melt-extrusion is not necessarily sufficient. In addition, when EVOH is melt-extruded, pressure differences, neck-in fluctuations, etc. tend to occur, and the melt moldability is not necessarily sufficient. Furthermore, in the conventional method, coloring or gelation tended to occur in the molded EVOH. [0004] To solve these problems, various method...

Claims

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Application Information

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IPC IPC(8): C08F210/08B32B27/32C08F2/06C08F8/12C08F210/02C08F218/08
CPCC08F8/12C08F218/08B32B27/32C08F210/02C08J5/18C08F2800/10C08F2810/50C08F216/06C08F2500/12C08F2500/26C08F210/08
Inventor 吉见一赖
Owner KURARAY CO LTD
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