US3256110A - Discoloration resistant cellulose article and method of manufacture - Google Patents
Discoloration resistant cellulose article and method of manufacture Download PDFInfo
- Publication number
- US3256110A US3256110A US379719A US37971964A US3256110A US 3256110 A US3256110 A US 3256110A US 379719 A US379719 A US 379719A US 37971964 A US37971964 A US 37971964A US 3256110 A US3256110 A US 3256110A
- Authority
- US
- United States
- Prior art keywords
- article
- rayon
- citric acid
- calcium nitrate
- percent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/02—Chemical after-treatment of artificial filaments or the like during manufacture of cellulose, cellulose derivatives, or proteins
Definitions
- the present invention relates to regenerated cellulose fibers and theinmanufacture, and more particularly to the stabilization of regenerated cellulose fibers and articles made therefrom against degradation on storage or exposure to high levels of energy.
- Regenerated cellulose articles have an inherent tendency to become discolored and lose tensile strength on storage, particularly when they have been exposed to high levels of energy. This presents a serious problem with light colored articles which must be stored or used over a prolonged period of time, particularly when they must be exposed to heat,- ionizing radiation or other forms of radiant energy in use, .hot air drying and sterilization, for example.
- Discoloration of regenerated cellulose articles is a particularly vexing problem in surgical articles such as surgical dressings, sponges, wipes and the like since it is highly desirable that such articles be white to connote cleanliness and lack of impurities, and the usual sterilization techniques employing steam, or high energy radiation from an electron beam, Roentgen ray machine, cobalt 60 or the like almost invariably cause substantial yellowing of the rayon.
- Substantial discoloration, i.e. yellowing of the article is always extremely objectionable in a normally white or colorless surgical dressing.
- the excess aqueous solution is removed and the filaments or staple are then dried in the presence of the stabilizing agents.
- The. total amount of calcium nitrate and citric acid or citrate ions which is employed may be varied within certain specific limits. It has been found, in general, that a useful degree of improvement in the stability of the regenerated cellulose articles is obtained by treatment with an aqueous solution containing at least about 0.025 percent by weight of each of the stabilizing agents in order to obtain a highly satisfactory degree of stabilization.
- the preferred concentration of each of the components in the calcium nitrate-citric acid bath is about 0.05 to 0.10 percent by weight.
- the stabilizing solution is, of course, on the acid side, and preferably within the range of from 4.0 to 5.0.
- the stabilization procedure is preferably carried out as a separate and final liquid treatment on the completely processed and washed but never-dried regenerated cellulose filament or fiber.
- the stabilizing agents calcium nitrate and citric acid are combined into one aqueous solution which is applied to the regenerated cellulose articles while they are still in a never-dried condition or after they have been dried.
- the aqueous solution containing the calcium nitrate and citric acid is applied within the normal operations for manufacturing viscose filaments or staple after washing of such never-dried other suitable means, after which the treated article is dried in air or a vacuum by conventional procedures to remove liquid water and leave the treating agents in situ on the article. It has been found that the rayon article normally picks up about its own weight of treating solution although it may retain as much as 1.5 to 2 times its own weight of solution depending upon the wringing technique or other method used to remove the excess solution.
- the primary standard for reflectance measurement is a layer of magnesium oxide prepared according to the instructions of the National Bureau of Standards. Although other color characteristics may be compared by the standard test, the chief coordinate of interest in the present case is coordinate b which indicates specimen colors from yellow to blue; minus values of b being blue, positive values, yellow and 0.0 being the value obtained for the White primary standard described above. Because of the differences between instruments and the difiiculties of making a primary standard, porcelain enamel plaques are calibrated against the primary standard and used as working standards. These plaques are available from the National Bureau of Standards, Washington DC. and the Gardner Laboratories, Bethesda, Maryland. All values used for comparison of the relative stability of the rayon samples referred to herein are expressed in plus scalar values of the b coordinate obtained by the standard test procedure which indicates the degree of yellowing of the sample.
- the present invention is capable of substantially improving the stability of regenerated cellulose articles even when exposed to very high levels of energy such as 2.5 megarads of cobalt 60 radiation.
- the invention is also useful for stabilizing rayon when exposed to lower energy levels such as those encountered in steam sterilization. It has been found that very low concentrations of calcium nitrate and citric acid, for example concentrations of from "0.002 percent to 0.01 percent by weight of each of the stabilizing agents, incorporated in an aqueous finishing bath are capable of stabilizing rayon against discoloration during and subsequent to sterilization with steam.
- the stabilizing agents of the present invention are operable under a wide variety of conditions. They may be employed to stabilize rayon against degradation by exposure to energy levels such as provided by dry heat at temperatures of the order of 250 F. or the moist heat of steam sterilization at temperatures of 240 to 260 F. for periods of 20 to 45 minutes.
- the present invention employing calcium nitrate in combination with citric acid provides a method which is unique in that it is capable of stabilizing rayon against degradation on exposure to higher levels of energy such as ionizing radiation.
- the invention is capable of providing substantial stabilization of rayon whether exposed to mild doses of low energy infrared radiation or large doses of ionizing radiation up to about 5 megarads or higher.
- the stabilization system of the present invention has many advantages over previously available systems, particularly for surgical purposes. Inasmuch as calcium nitrate and citric acid are fully oxidized they do not react with stainless steel hospital equipment such as sterilization vessels, hypodermic syringes and the like, which is a disadvantage of the bisulfite stabilization systems of the prior art. This is also an advantage in that the new stabilizing system does not reduce iodine or similar medicaments or antiseptic solutions and do not bleach dyes used in such preparations.
- a method of manufacturing a discoloration resistant cellulose article comprising washing a preshaped regenerated cellulose article free of soluble impurities, thoroughly wetting the article with a solution containing as color stabilizing agents from about 0.05 percent .to about 0.20 percent by weight of each calcium nitrate and citric acid and drying the article in the presence of the stabilizing agents.
- Method of manufacturing a discoloration resistant cellulose fiber comprising washing fully regenerated and never-dried fibers of viscose rayon free of soluble impurities, thoroughly wetting the fibers with a solution containing as color stabilizing agents about 0.05 percent to about 0.20 percent by weight of each of calcium nitrate and citric acid and drying the fibers in the presence of the stabilizing agents.
Description
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US379719A US3256110A (en) | 1964-07-01 | 1964-07-01 | Discoloration resistant cellulose article and method of manufacture |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US379719A US3256110A (en) | 1964-07-01 | 1964-07-01 | Discoloration resistant cellulose article and method of manufacture |
Publications (1)
Publication Number | Publication Date |
---|---|
US3256110A true US3256110A (en) | 1966-06-14 |
Family
ID=23498400
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US379719A Expired - Lifetime US3256110A (en) | 1964-07-01 | 1964-07-01 | Discoloration resistant cellulose article and method of manufacture |
Country Status (1)
Country | Link |
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US (1) | US3256110A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070003605A1 (en) * | 2005-07-04 | 2007-01-04 | Josef Pesso | Non-discoloring sterilized wipe |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2922728A (en) * | 1956-11-05 | 1960-01-26 | American Enka Corp | Prevention of yellowing in freshly spun viscose rayon with tartaric, citric or gluconic acid |
US3012844A (en) * | 1955-03-28 | 1961-12-12 | American Viscose Corp | Cellulosic material |
-
1964
- 1964-07-01 US US379719A patent/US3256110A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3012844A (en) * | 1955-03-28 | 1961-12-12 | American Viscose Corp | Cellulosic material |
US2922728A (en) * | 1956-11-05 | 1960-01-26 | American Enka Corp | Prevention of yellowing in freshly spun viscose rayon with tartaric, citric or gluconic acid |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070003605A1 (en) * | 2005-07-04 | 2007-01-04 | Josef Pesso | Non-discoloring sterilized wipe |
US8366688B2 (en) | 2005-07-04 | 2013-02-05 | Fischer Pharmaceuticals Ltd. | Non-discoloring sterilized wipe |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: KELLOGG CREDIT CORPORATION A DE CORP. Free format text: AGREEMENT WHEREBY SAID HELLER AND RAYONIER RELEASES ALL MORTGAGES AND SECURITY INTERESTS HELD BY AVTEX ON APRIL 28, 1978, AND JAN. 11, 1979, RESPECTIVELY AND ASSIGNS ITS ENTIRE INTEREST IN SAID MORT-AGAGE AGREEMENT TO ASSIGNEE;ASSIGNORS:WALTER E. HELLER & COMPANY, INC. A NY CORP.;ITT RAYONIER INCORPORATED, A DE CORP.;AVTEX FIBERS INC., A NY CORP.;REEL/FRAME:003959/0350 Effective date: 19800326 Owner name: NEW ENGLAND MUTUAL LIFE INSURANCE COMPANY 501 BOYL Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: JOHN HANCOCK MUTUAL LIFE INSURANCE COMPANY JOHN HA Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: BALBOA INSURANCE COMPANY C/O THE PAUL REVERE EQUIT Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: PAUL REVERE LIFE INSURANCE COMPANY THE C/O THE PAU Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: PROVIDENT ALLIANCE LIFE INSURANCE COMPANY C/O THE Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: WESTERN AND SOUTHERN LIFE INSURANCE COMPANY THE C/ Free format text: AS SECURITY FOR INDEBTEDNESS RECITED ASSIGNOR GRANTS , BARGAINS, MORTGAGES, PLEDGES, SELLS AND CREATES A SECURITY INTEREST WITH A LIEN UNDER SAID PATENTS, SUBJECT TO CONDITIONS RECITED.;ASSIGNOR:AVTEX FIBERS INC. A NY CORP.;REEL/FRAME:003959/0219 Effective date: 19810301 Owner name: WALTER E. HELLER & COMPANY, INC., A CORP. OF DEL. Free format text: AGREEMENT WHEREBY AETNA RELEASES AVTEX FROM ALL MORTAGES AND SECURITY INTERESTS IN SAID INVENTIONS AS OF JANUARY 11,1979, AND ASSIGNS TO ASSIGNEE THE ENTIRE INTEREST IN SAID MORTAGE AGREEMENT TO ASSIGNEE;ASSIGNORS:AETNA BUSINESS CREDIT, INC., A CORP. OF N.Y.;AVTEX FIBERS, INC, A CORP. OF NY;KELLOGG CREDIT CORP., A CORP. OF DEL.;REEL/FRAME:003959/0250 Effective date: 19800326 |