Abstract An improved method of producing a polyacrylonitrile extrusion solution particularly suited for the production of shaped articles, especially fibers, which eliminates several process steps previously associated with the polymerization of the acrylic polymer and the subsequent formation of the extrusion solution. The method is particularly applicable to high acrylic polymers such as those containing more than about 85 percent acrylonitrile wherein the polymers are formed by aqueous suspension polymerization methods. The wet acrylic polymer produced is directly used in an extrusion process by solvating the polymer with a lower alkyl nitrile, such as acetonitrile, to form the extrusion solution. The solvation is accomplished by adjusting the polymer water content to about 1 to 40 percent by weight of the polymer, adding sufficient acetonitrile to provide a polymer-solvent mixture of 20 to 70 percent of polymer solids by weight and subsequently heating the mixture under at least autogeneous pressure to above the atmospheric boiling point of the solvent to form a homogeneous polymer solution.
The process of claim 1 wherein the lower alkyl nitrile is acetonitrile.
Claim 2
Dependent Claim
17 words
The process of claim 2 wherein the acrylonitrile is copolymerized with at least one other copolymerizable monomer.
Claim 3
Dependent Claim
96 words
The process of claim 1 wherein the polymer comprises at least 85 percent acrylonitrile and two additional copolymerizable ethylenically unsaturated monomers, one of which is a sulfur-containing monomer, said polymer being admixed with acetonitrile and water in a proportion of about 35 to 70 percent polymer solids with the residual being acetonitrile and water in a weight ratio of 2 to 40 percent water and 60 to 98 percent acetonitrile, said mixture being heated to a temperature of 100* to 150* C under at least the autogeneous pressure with mixing to obtain a homogeneous solution thereof.
Claim 4
Dependent Claim
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The process of claim 4 wherein the copolymerizable monomers are methylacrylate and sodium methallyl sulfonate.
Claim 5
Dependent Claim
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The process of claim 4 further comprising directly feeding the homogeneous solution under elevated temperatures and superatmospheric pressure to a means for extruding said solution and extruding said solution.