US2593173A - Process of refining chemical pulp - Google Patents
Process of refining chemical pulp Download PDFInfo
- Publication number
- US2593173A US2593173A US765248A US76524847A US2593173A US 2593173 A US2593173 A US 2593173A US 765248 A US765248 A US 765248A US 76524847 A US76524847 A US 76524847A US 2593173 A US2593173 A US 2593173A
- Authority
- US
- United States
- Prior art keywords
- pulp
- chemical pulp
- heating
- washed
- room temperature
- 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
Links
- 229920001131 Pulp (paper) Polymers 0.000 title claims description 17
- 238000000034 method Methods 0.000 title claims description 12
- 238000007670 refining Methods 0.000 title description 4
- 238000010438 heat treatment Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-PWCQTSIFSA-N Tritiated water Chemical compound [3H]O[3H] XLYOFNOQVPJJNP-PWCQTSIFSA-N 0.000 claims 1
- 239000000725 suspension Substances 0.000 claims 1
- WQYVRQLZKVEZGA-UHFFFAOYSA-N hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 description 4
- 239000007900 aqueous suspension Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229920000297 Rayon Polymers 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 241000197727 Euscorpius alpha Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229920005610 lignin Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
- D21C9/08—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching
- D21C9/083—Removal of fats, resins, pitch or waxes; Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching with inorganic compounds
Definitions
- viscose pulp When refining chemical pulp according to chemical methods variations in lignin content and viscosity often cause great difficulties in normal refining processes wherefore, generally, very even quality is demanded of chemical pulp intended for some special purpose.
- One of the properties required of e. g. viscose pulp is that it has a specified viscosity and here no greater variations than 1 cp. are as a rule permissible.
- the preparation of such viscose pulp has resorted to rigorous hypochlorite treatment. The violence of this treatment is evidenced inter alia by a drop in the percentage amount of the most valuable ingredient'of chemical pulp, i. e. alpha cellulose, and by the rise of the copper number, which designates the amount oxycelluse.
- a process of making refined chemical pulp comprising, selecting washed, defiberecl and strained chemical pulp, chlorinating such pulp at room temperature, forming such pulp into a 1l5% aqueous suspension partially washed with water, and heating such pulp at a temperature above room temperature but not over C. for a period of time of about 10 to 200 minutes at a pH value lower than 5.
- a process of making refined chemical pulp comprising, selecting washed, defibered and strained chemical pulp, chlorinating such pulp at room temperature, then heating such pulp at a temperature above that of room temperature but below 100 C., and continuing that heating for a period of time at about 10 to 200 minutes at a pH value lower than 5.
- a process of making refined chemical pulp comprising, selecting washed, defibred and strained chemical pulp, chlorinating such pulp at room temperature, subsequently heating such pulp as a 1-15% aqueous suspension at a temperature of approximately 40 C. and continuing such heating for a period of time of from 10 to 200 minutes at a pH value lower than 5.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
Description
Patented Apr. 15, 1952 PROCESS OF REFINING CHEMICAL PULP Turma Norta and Yrjii Sivola, Imatra, Finland, assignors to Enso-Gutzeit Osakeyhtiii, Helsinki, Finland, a corporation of the Community of Jaaski in the Republic of Finland No Drawing. Application July 31, 1947, Serial No. 765,248. In Sweden October so, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires October 30, 1963 Claims.
When refining chemical pulp according to chemical methods variations in lignin content and viscosity often cause great difficulties in normal refining processes wherefore, generally, very even quality is demanded of chemical pulp intended for some special purpose. One of the properties required of e. g. viscose pulp is that it has a specified viscosity and here no greater variations than 1 cp. are as a rule permissible. In order to reduce and smooth out viscosity the preparation of such viscose pulp has resorted to rigorous hypochlorite treatment. The violence of this treatment is evidenced inter alia by a drop in the percentage amount of the most valuable ingredient'of chemical pulp, i. e. alpha cellulose, and by the rise of the copper number, which designates the amount oxycelluse.
On investigating methods for obviation of the above mentioned defects it was found that if washed, defibered and strained chemical pulp was chlorinated and subsequently heated as a 1-15 per cent aqueous suspension to a temperature somewhat exceeding that of a room and kept at this temperature a specified Period of time dependent on the qaulity of chemical pulp under treatment, ranging in practise from 10- 200 min., the cellulose molecules break up, partly through the agency of acid substances created during chlorination, thus causing a drop in viscosity. As already mentioned, heating must be carried out at a temperature exceeding that of a room, preferably at 40 0.; however it is not advisable to exceed 100 C. because of practical and economical reasons. The heating of chem- .ical pulp can also be applied subsequently to vantages, achieved by the process hereinabove described as compared with the hypochlorite treatment generally used at the moment, are
that inter alia the alpha content of the chemical pulp increases, the pentosan content decreases and the copper number drops.
What we claim is:
1, A process of making refined chemical pulp comprising, selecting washed, defiberecl and strained chemical pulp, chlorinating such pulp at room temperature, forming such pulp into a 1l5% aqueous suspension partially washed with water, and heating such pulp at a temperature above room temperature but not over C. for a period of time of about 10 to 200 minutes at a pH value lower than 5.
2. A process as defined in claim 1 and including adding acid to the partially washed chemical pulp after chlorination in sufiicient amount to lower the pH value under 5.
3. A process as defined in claim 1 and including introducing chlorine into the pulp while the heating is taking place to lower the pH value under 5. l
4. A process of making refined chemical pulp comprising, selecting washed, defibered and strained chemical pulp, chlorinating such pulp at room temperature, then heating such pulp at a temperature above that of room temperature but below 100 C., and continuing that heating for a period of time at about 10 to 200 minutes at a pH value lower than 5.
5. A process of making refined chemical pulp comprising, selecting washed, defibred and strained chemical pulp, chlorinating such pulp at room temperature, subsequently heating such pulp as a 1-15% aqueous suspension at a temperature of approximately 40 C. and continuing such heating for a period of time of from 10 to 200 minutes at a pH value lower than 5.
TURll/IA NORTA. YRJO SIVOLA.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,705,897 Bradley Mar. 19, 1929 1,941,154 Richter Dec. 26, 1933 1,967,347 Bayerl July 24, 1934 2,065,395 Richter Dec. 22, 1936 2,070,893 Glass Feb. 16, 1937 2,159,376 Freeman May 23, 1939 2,198,706 Sheldon Apr. 30, 1940 OTHER REFERENCES Cellulose and its Derivatives, by Ott, published by Interscience Publishers, Inc., N. Y., N. Y., 1943, pp. 588-589, 598, 599, and 603.
Claims (1)
1. A PROCESS OF MAKING REFINED CHEMICAL PULP COMPRISING, SELECTING WASHED, DEFIBERED AND STRAINED CHEMICAL PULP, CHLORINATING SUCH PULP AT ROOM TEMPERATURE, FORMING SUCH PULP INTO A 1-15% AQEUOUS SUSPENSION PARTIALLY WASHED WITH WATER, AND HEATING SUCH PULP AT A TEMPERATURE ABOVE ROOM TEMPERATURE BUT NOT OVER 100* C. FOR A PERIOD OF TIME OF ABOUT 10 TO 200 MINUTES AT A PH VALUE LOWER THAN 5.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE2593173X | 1943-10-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2593173A true US2593173A (en) | 1952-04-15 |
Family
ID=20426424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US765248A Expired - Lifetime US2593173A (en) | 1943-10-30 | 1947-07-31 | Process of refining chemical pulp |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2593173A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1705897A (en) * | 1922-03-16 | 1929-03-19 | Bradley Linn | Bleaching of pulp |
| US1941154A (en) * | 1930-09-06 | 1933-12-26 | Brown Co | Process of reducing the solution viscosity of cellulose fiber |
| US1967347A (en) * | 1932-10-08 | 1934-07-24 | Ig Farbenindustrie Ag | Process for producing a cellulose of high content of alpha cellulose |
| US2065395A (en) * | 1935-08-27 | 1936-12-22 | Brown Co | Fractured wood fiber product |
| US2070893A (en) * | 1935-05-10 | 1937-02-16 | Glass Hugh Bryson | Process for improving the color of wood pulp |
| US2159376A (en) * | 1938-07-19 | 1939-05-23 | Dow Chemical Co | Making of low viscosity cellulose ethers |
| US2198706A (en) * | 1936-11-23 | 1940-04-30 | Cellulose Res Corp | Refining wood pulp |
-
1947
- 1947-07-31 US US765248A patent/US2593173A/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1705897A (en) * | 1922-03-16 | 1929-03-19 | Bradley Linn | Bleaching of pulp |
| US1941154A (en) * | 1930-09-06 | 1933-12-26 | Brown Co | Process of reducing the solution viscosity of cellulose fiber |
| US1967347A (en) * | 1932-10-08 | 1934-07-24 | Ig Farbenindustrie Ag | Process for producing a cellulose of high content of alpha cellulose |
| US2070893A (en) * | 1935-05-10 | 1937-02-16 | Glass Hugh Bryson | Process for improving the color of wood pulp |
| US2065395A (en) * | 1935-08-27 | 1936-12-22 | Brown Co | Fractured wood fiber product |
| US2198706A (en) * | 1936-11-23 | 1940-04-30 | Cellulose Res Corp | Refining wood pulp |
| US2159376A (en) * | 1938-07-19 | 1939-05-23 | Dow Chemical Co | Making of low viscosity cellulose ethers |
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