United Sellevu 1 Vy Vayu up ~~~~ Patented Jan
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6 a. 33. SR ty a w WB w w w " ()R 3 26 s () ) {} ur O 3,296,000 United Sellevu 1 Vy Vayu up ~~~~ Patented Jan. 3, 1967 2 It is, however, soluble in certain organic solvents and SHAPED REGENERAESCELLULOSE3,296,000 PRODUCTS thus various different procedures may be employed for HAVENG BACTEREOSTATIC PROPERTIES introducing the same into the viscose. In one such pro Gregory C. Bockino, Media, and Joseph W. Schappel, cedure, organic solvent solutions of 3,4,4-trichlorocarba Morton, Pa., assignors, by mesne assignments, to FMC nilide may be injected directly into a viscose under high Corporation, San Jose, Calif., a corporaion of Dela shear blending conditions. Organic solvents found to be Ware satisfactory include polyethylene glycol, dimethyl form No Drawing. Continuation of application Ser. No. amide and acetone. Solutions of from about 1% to 10 261,195, Feb. 26, 1963. This application Apr. 6, 1966, or 15% or more of the 3,4,4'-trichlorocarbanilide in the Ser. No. 549,514 O above-noted solvents provide for a fine dispersion of the 8 Clains. (C. 106-15) bacteriostatic compound when injected into the viscose to This application is a continuation of our application the extent of from 0.3% to 7%, based on the weight of Serial Number 261,195, filed February 26, 1963, now the cellulose. When relatively dilute solutions are em abandoned. ployed, the bacteriostatic compound appears as minute The present invention relates to the production of 5 particles in the viscose and thus satisfactory spinning con shaped bodies, such as filaments and fibers, of regenerated ditions can be well maintained. As the concentration of cellulose having bacteriostatic properties. the 3,4,4-trichlorocarbanilide in the solvent is increased, Conventional procedures for imparting bacteriostatic there is a greater tendency for the bacteriostatic compound properties to shaped bodies of regenerated cellulose gen to precipitate as comparatively large plate-like crystals erally involve impregnating or coating of regenerated cel 20 which readily clog the spinneret openings. lulose filaments, fibers or fabrics formed therefrom with a In lieu of direct injection into the viscose, the organic suitable bacteriostatic composition followed by drying. solvent solution of the bacteriostatic compound, prepared Such bacteriostatic finishes often alter the hand or other as described above, may be precipitated as a sub-micron physical properties of the treated materials and, more dispersed 3,4,4-trichlorocarbanilide in water containing a important, are generally fugitive and are thus readily re 25 suitable surface active wetting or dispersing agent. For moved by laundering or eaching in water. example, a 1.5% solution of 3,4,4'-trichlorocarbanilide in It is an object of this invention to provide viscose solu acetone or dimethyl formamide, at room temperature, may tions which are capable of being coagulated to form im be slowly added to and vigorously mixed with an aqueous proved shaped bodies of regenerated cellulose having bac solution containing about 0.05% Duponol ME (sodium teriostatic properties. 30 lauryl sulfate). The resulting dispersion contains about It is a further object of this invention to provide im 0.4% of 3,4,4'-trichlorocarbanilide having particle sizes of proved bacteriostatic regenerated cellulose filaments, about 1 micron or less, and may be injected directly into fibers, fabrics and like structures which retain their bac the viscose which is being spun. Alternatively, the disper teriostatic properties after a considerable number of sion may be centrifuged or permitted to settle and de launderings in an aqueous medium. 35 canted when concentration of the bacteriostatic compound Still further objects and advantages of the present in and/or solvent recovery are important considerations. vention will appear in the following detailed description With these last mentioned procedures, the bacteriostatic and claims. particles are redispersed in an aqueous medium before In accordance with the present invertion, regenerated injection into a viscose. cellulose filaments, fibers and other shaped products hav 40 With the above-described precipitation procedure the ing bacteria inhibiting properties are formed from a viscose small particles of the bacteriostatic particles provided are containing 3,4,4-trichlorocarbanilide in the particulate conducive to good spinning operations for extended pe form. Aside from the incorporation of the bacteriostatic riods, and the bacteriostatic properties of the shaped compound noted, the viscose and the spinning bath em regenerated cellulose products produced by this procedure ployed in making the shaped regenerated cellulose prod 45 are generally satisfactory. It has been found, however, ucts of the present invention may be of conventional or that particles of 3,4,4'-trichlorocarbanilide of one micron known composition. or less are usually solvated to a large extent after some The manufacture of shaped products from viscose which ten or fifteen laundering cycles. This particular proce exhibit bacteriostatic properties entails difficulties which dure is therefore best suited for producing shaped regen are not generally encountered in melt or solution spinning erated cellulose products which undergo little laundering procedures. The bacteriostatic compound, and solvents or are intended to exhibit bacteriostatic properties for used with such compound, must not only be compatible limited periods. with the viscose solution, but must be capable of resisting The 3,4,4-trichlorocarbanilide available commercially the acid environment and the Subsequent processing pro includes particles having an average size of from about cedures which are normally involved in the manufacture 3 to 5 microns and a maximum size which may range up of regenerated cellulose products. Experience has shown to about 20 microns. By attriting this commercial com that many bacteriostatic compounds survive the viscose pound, as by a conventional dry-fluid energy grinding sys and spinning operations, only to be lost in the final proc tem, the particles can be reduced in size to an average of essing procedures which include de-Sulfiding, bleaching about 2 microns and a maximum of about 7 microns. and long periods of water washing. The present invention 60 Particles of this size are not entirely satisfactory for good is predicated on our discovery that 3,4,4'-trichlorocarba spinnability. These larger particles can be removed by nilide can survice the viscose, Spinning, and after-treating procedures employed in making of regenerated cellulose permitting the same to settle from an aqueous dispersion products and methods which we have developed for in of such attrited materials. For example, an aqueous dis corporating the 3,4,4-trichlorocarbanilide compound into persion originally containing about 8% of attrited 3,4,4'- the viscose in precipitate or particulate form. trichlorocarbanilide and a surface active agent, showed The 3,4,4'-trichlorocarbanilide compound has very low fewer particles larger than 3 or 4 microns after a settling solubility in water. This characteristic is, of course, ideal period of between 3 and 4 hours. This remaining disper since the active bacteriostatic agent which is removed from sion of "classified' particles may be injected into the vis the surface of the shaped products through laundering is 70 cose and enables acceptable spinning operations to he continuously replaced with additional material which is effected for extended periods. leached under controlled rates from within such products. As noted above, the presence of large size particles 32 is C. s. 33 F 8,296,000 3 4. renders the commercially available 3,4,4-trichlorocar alter the fine structure of the cellulose as is commonly banilide unsuitable for uninterrupted spinning operations. practiced in the industry. It was discovered, however, that these larger size particles The viscose is formed in the conventional manner and were caused by flocculation and agglomeration of the either during its preparation or just prior to spinning may smaller size particles, and that this effect could be elimi 5 be further modified by the addition of a viscose or coagula nated or materially reduced by employing a non-ionic tion modifier. A large number of modifiers are known (low foaming) surface active agent, such as "SteroX AP and are in use in the production of the various types of (polyoxyethylene ether). For example, an 8.0% con viscose rayon. These modifiers include polyoxyalkylene centration of commercially available 3,4,4-trichlorocar glycols such as polyoxyethylene glycols, polyoxypropylene banilide may be dispersed in an aqueous Solution of 10 glycols and block copolymers of propylene and ethylene 0.05% “Sterox AP' and may be injected into a conven oxides; various amines including monoamines, diamines tional viscose to provide the same with a 2% concentra and poiyamines such as diethylamine, dimethylamine, tion of 3,4,4-trichlorocarbanilide, based on the Weight of ethylene diamine and diethylene triannine; reaction prod the cellulose. Such dispersion has been found to provide licts of alkylene oxides with fatty acids, fatty alcohols, trouble-free spinning of regenerated cellulose fila fatty amines, aromatic acids, aromatic alcohols, aromatic ments for extended periods with no accumulation of in amines, partial esters of fatty acids and polyhydric alco soluble matter being apparent on the filters or Spinneret hols such as reaction products of ethylene oxide with normally employed. As with the previously