DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EVOH copolymers that are suitable for use herein will generally contain at least about 55, and as much as 80, weight percent of vinyl alcohol in the molecule; the preferred copolymers will contain about 60 to 75 weight percent of the vinyl alcohol moiety.
The remainder of the molecule will consist essentially of ethylene; however, because such products are produced by hydrolysis of ethylene vinyl acetate copolymers, some residual vinyl acetate will usually be present.
Normally, there will be less than about 3 weight percent of vinyl acetate in the EVOH molecule, and preferably it will be present at a level below 1.
5 percent.
The EVOH copolymers will typically have molecular weights in the range of about 20,000 to 30,000, corresponding roughly to melt indices ranging from about 9 to 1.
5.
The melt index values for these resins are determined in accordance with ASTM test D-1238, Procedure E or L, using a weight of 2160 grams and a temperature of either 190 degrees or 230 degrees Centigrade, as appropriate.
Typically, the copolymers will have densities of about 1.
1 to 1.
2, and their melting points will normally range from about 325 degrees to 375 degrees Fahrenheit; suitable temperatures for processing them will be about 400 degrees to 480 degrees Fahrenheit, in the unplasticized state.
While the degradation temperature of EVOH is generally regarded to be about 450 degrees Fahrenheit, it should be appreciated that this is not inconsistent, due to the residence time factor and its effect upon degradation.
Specific EVOH resins that are suitable for use are available from Kuraray and from Nippon Gohsei, both of Japan, the products of the former company being designated EP-E and EP-F, and those of the latter company being designated GL-D and GL-E, respectively.
The plasticizer utilized to produce the novel blends of the present invention must, of course, be one that is compatible with the EVOH copolymer employed, so as to avoid excessive blooming
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Liquid Purification 
