US20030050472A1 - Alkylene oxide modified hardwood cellulose - Google Patents
Alkylene oxide modified hardwood cellulose Download PDFInfo
- Publication number
- US20030050472A1 US20030050472A1 US09/943,650 US94365001A US2003050472A1 US 20030050472 A1 US20030050472 A1 US 20030050472A1 US 94365001 A US94365001 A US 94365001A US 2003050472 A1 US2003050472 A1 US 2003050472A1
- Authority
- US
- United States
- Prior art keywords
- cellulose
- pulp
- hardwood
- mercerized
- pulps
- 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.)
- Abandoned
Links
- 229920002678 cellulose Polymers 0.000 title claims abstract description 50
- 239000001913 cellulose Substances 0.000 title claims abstract description 49
- 239000011121 hardwood Substances 0.000 title claims abstract description 33
- 125000002947 alkylene group Chemical group 0.000 title claims description 21
- 238000000034 method Methods 0.000 claims abstract description 38
- 230000008569 process Effects 0.000 claims abstract description 35
- 229920002301 cellulose acetate Polymers 0.000 claims abstract description 15
- 238000006467 substitution reaction Methods 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 11
- TWNIBLMWSKIRAT-VFUOTHLCSA-N levoglucosan Chemical group O[C@@H]1[C@@H](O)[C@H](O)[C@H]2CO[C@@H]1O2 TWNIBLMWSKIRAT-VFUOTHLCSA-N 0.000 claims abstract description 7
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 5
- 239000003518 caustics Substances 0.000 claims description 27
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical group CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 238000002360 preparation method Methods 0.000 claims description 7
- 230000000397 acetylating effect Effects 0.000 claims 1
- 238000004519 manufacturing process Methods 0.000 abstract description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 48
- 238000006640 acetylation reaction Methods 0.000 description 24
- 230000021736 acetylation Effects 0.000 description 18
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 16
- 239000011122 softwood Substances 0.000 description 13
- 239000003054 catalyst Substances 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 11
- 230000009257 reactivity Effects 0.000 description 11
- 229920000742 Cotton Polymers 0.000 description 9
- 238000000605 extraction Methods 0.000 description 9
- -1 hydroxypropoxy group Chemical group 0.000 description 9
- 239000000047 product Substances 0.000 description 9
- ILJSQTXMGCGYMG-UHFFFAOYSA-N triacetic acid Chemical compound CC(=O)CC(=O)CC(O)=O ILJSQTXMGCGYMG-UHFFFAOYSA-N 0.000 description 8
- 230000008901 benefit Effects 0.000 description 6
- 239000000835 fiber Substances 0.000 description 6
- 239000002655 kraft paper Substances 0.000 description 6
- 238000011084 recovery Methods 0.000 description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 238000005517 mercerization Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 229920001131 Pulp (paper) Polymers 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 241000208140 Acer Species 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 2
- 238000004061 bleaching Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000013068 control sample Substances 0.000 description 2
- 230000032050 esterification Effects 0.000 description 2
- 238000005886 esterification reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000013055 pulp slurry Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 241000157282 Aesculus Species 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- BRLQWZUYTZBJKN-UHFFFAOYSA-N Epichlorohydrin Chemical compound ClCC1CO1 BRLQWZUYTZBJKN-UHFFFAOYSA-N 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
- ZZSNKZQZMQGXPY-UHFFFAOYSA-N Ethyl cellulose Chemical compound CCOCC1OC(OC)C(OCC)C(OCC)C1OC1C(O)C(O)C(OC)C(CO)O1 ZZSNKZQZMQGXPY-UHFFFAOYSA-N 0.000 description 1
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 1
- 244000166124 Eucalyptus globulus Species 0.000 description 1
- 240000000731 Fagus sylvatica Species 0.000 description 1
- 235000010099 Fagus sylvatica Nutrition 0.000 description 1
- 229920002488 Hemicellulose Polymers 0.000 description 1
- 241000219000 Populus Species 0.000 description 1
- 241000183024 Populus tremula Species 0.000 description 1
- 241000219492 Quercus Species 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical group C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 1
- 239000003377 acid catalyst Substances 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 229920003086 cellulose ether Polymers 0.000 description 1
- 238000010411 cooking Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229920001249 ethyl cellulose Polymers 0.000 description 1
- 235000019325 ethyl cellulose Nutrition 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052736 halogen Chemical group 0.000 description 1
- 125000005843 halogen group Chemical group 0.000 description 1
- 235000010181 horse chestnut Nutrition 0.000 description 1
- 125000005113 hydroxyalkoxy group Chemical group 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
- C08B13/00—Preparation of cellulose ether-esters
Definitions
- This invention relates to a process for the modification of cellulose and particularly to a process for the preparation of reactive cellulosic hardwood pulp to make cellulose acetate with superior properties.
- the treatment of cellulose with alkali under “mercerizing conditions” is a well known procedure which converts cellulose from its native form, cellulose I, to a more thermodynamically stable, less crystalline form, cellulose II.
- the critical concentration of the caustic solution (weight % of the solution of sodium hydroxide or, less often, potassium hydroxide) necessary for mercerization is dependent upon both temperature and type of cellulose.
- the caustic solution strength for mercerizing conditions at ambient temperatures will be more than 5%, and usually about 6-16%. For a given caustic concentration, mercerization occurs more readily at low temperatures than high.
- a greater caustic concentration is required to mercerize a prehydrolyzed kraft pulp than a sulfite pulp, for example.
- the conditions (temperature, caustic concentration) required to mercerize various cellulosic materials are well known.
- Propylene oxide was found to be the preferred alkylene oxide for making mercerized softwood fibers which are reactive in low catalyst acetylation processes with desirable properties being achieved with hydroxypropoxy group (—OC 3 H 6 OH) content range of 3.6 to 5.7%, corresponding to a degree of molar substitution (d.s.) of 0.08 to 0.13 per anhydroglucose unit in cellulose.
- hydroxypropoxy group —OC 3 H 6 OH
- the foregoing and other objects of the invention are achieved by the preparation of reactive cellulose by mercerizing hardwood cellulosic material, and reacting the mercerized hardwood cellulose with an hydroxyalkylating agent to a molar degree of substitution of the cellulose ranging from about 0.04 to about 0.15 per anhydroglucose unit in cellulose, the degree of substitution being insufficient to render the cellulose appreciably soluble in water, and recovering the substantially water insoluble product.
- the hardwood sources which are suitable for use in the invention are woods such as gum, maple, oak, eucalyptus, poplar, beech and aspen.
- the hydroxyalkylating agents useful in the invention are generally the alkylene oxides, including ethylene, propylene and butylene oxides and halogen substituted alkylene oxides such as epichlorohydrin. Benefits of the invention are achieved with about 2.0% to about 5.5% by weight hydroxyalkoxy (—OC n H 2n OH) group content on the cellulose. This corresponds to a degree of molar substitution per anhydroglucose unit in cellulose of from about 0.04 to about 0.15.
- hydroxypropoxy (—OC 3 H 6 OH)groups using propylene oxide is more efficient in promoting the benefits of the invention, and also represents a safer, less costly process, it is a preferred alkylene oxide for use in the invention.
- benefits can be expected in about the 2.5 to 4.0% hydroxypropoxy (—OC 3 H 6 OH) group content range which corresponds to a degree of molar substitution of about 0.055 to 0.09 per anhydroglucose unit in cellulose.
- the hardwood cellulosic pulp may be pretreated with NaOH which acts both to mercerize the pulp and as a catalyst for the reaction of cellulose with alkylene oxides.
- NaOH acts both to mercerize the pulp and as a catalyst for the reaction of cellulose with alkylene oxides.
- hydroxyalkylation will be conducted at the same caustic solution concentration as the mercerizing reaction, although it need not. Solution concentrations from 1 to 40% may be used for hydroxyalkylation.
- Certain bleaching and refining operations for cellulosic pulps involve a cold caustic extraction stage utilizing from 6 to 16% caustic solution at ambient temperatures (about 5° to about 400° C.) to extract hemicelluloses. During the cold caustic extraction stage, mercerization occurs. It has been found that reactive cellulosic pulps of acetylation quality may be produced by combining into one integral operation the cold caustic extraction stage using mercerizing conditions with alkylene oxide modification of the pulp.
- caustic solution may be used to mercerize the pulp.
- a preferred method of carrying out the present invention is to first conduct a cold caustic extraction using from 8 to 20%, and preferably 10 to 16%, caustic solution at a temperature of from 150 to 35° C., preferably 23° to 25° C., at a low consistency (weight of pulp per total weight of pulp slurry) of from 1 to 10%, preferably about 3%.
- the pulp slurry should then be dewatered to a high consistency of from about 10 to over 50%, preferably over 25%, using a centrifuge and/or press and then reacted with an alkylene oxide in the gas phase (25° C., for ethylene oxide, 50° C.
- the consistency should be increased as high as possible (to about 50% or more) to minimize side reactions of alkylene oxides with water.
- the caustic concentration should preferably remain at the mercerizing level, i.e., at 6 to 40%, preferably 8 to 20% caustic.
- a cold caustic refining process of the type which typically may be used in the practice of the present invention, is more fully disclosed in U.S. Pat. No. 3,148,106. Reference to the foregoing patent should be made for a more complete description of such a refining process.
- a wide variety of hardwood cellulosic material, principally pulps, are useful in the practice of the present invention, including both prehydrolyzed kraft and sulfite pulps. While the process is preferably combined with a refining operation, the process is nevertheless useful for both bleached and unbleached pulps.
- the invention is particularly useful for the preparation of acetate grade pulps.
- the reactive pulps of the invention may be used for the manufacture of other cellulose derivatives and plastics, including other cellulose esters and cellulose ethers such as ethyl cellulose.
- the very low triacetate haze (or clarity) values achieved utilizing hardwood pulp in accordance with the invention are equivalent to those from cotton linters pulp. Due to the excellent triacetate clarity values of cotton linters, compared to those attainable from commercial wood cellulose acetate pulps, cotton linters have been the preferred source material for premium acetate end-use markets, such as liquid crystal displays (LCDs).
- the PO modified, mercerized hardwood pulps according to the invention can compete in this market and also in manufacture of high quality triacetate film for professional photography.
- modified hardwood pulps of the invention react faster than cotton linters in low catalyst acetylation reactions.
- a cellulosic pulp (272 g, 100 g oven dried-o.d.) which had never been previously dried was prepared from hardwood (a mixture of principally gum, oak and maple) by a steam prehydrolyzed kraft cooking process and several bleach stages prior to cold caustic extraction (CCE) in a 10% NaOH solution at 3.0% consistency (100 g o.d. pulp in 3233.3 g of 10% NaOH solution).
- CCE cold caustic extraction
- the pulp was slurried for 10 minutes at a temperature of 24-25° C. before its recovery in a small-scale centrifuge for 10 minutes to remove filtrate and recover 348.5 g of alkaline pulp stock. This entire process was repeated two more times using 100 g o.d.
- each stock was quenched by addition of large quantities of water and allowed to cool before processing.
- the treated pulps were then processed at ambient temperatures by slurrying in water followed by recovery and numerous water washes in a Buchner funnel.
- the pulps were then reslurried in water, and acidified to pH between 2.5-3.0 with dilute sulfuric acid, and stirred for at least five minutes before recovery in a Buchner funnel and numerous water washes.
- All four similarly processed stocks from the plastic reaction vessels were combined and slurried together prior to recovery, sheeting, and drying to recover 306.3 g of stock at 89% o.d., or overall yield from starting pulp of 90.1%.
- the pulp had a hydroxypropoxy content of 2.9%.
- Example 1 was repeated but 16% NaOH solution was used for CCE rather than 10% NaOH.
- the PO treatment level was again 10%, being based on the o.d. pulp weight of the cold caustic extracted stock. Overall pulp product yield from starting stock was about 90.7%. The resulting pulp had a hydroxypropoxy content of 3.3%.
- Example 2 was repeated, except that 12.5% PO was added rather than 10%.
- the overall pulp product yield was about 90.9% from starting stock.
- the resulting pulp had a hydroxypropoxy content of 3.7%.
- Example 2 was repeated, except that 15% PO was added rather than 10%. Overall pulp product yield was about 91.0%. The resulting pulp had a hydroxypropoxy content of 4.5%.
- control pulp samples (not reacted with PO) were prepared by processing the same starting pulp using 10 and 16% NaOH, respectively, for CCE (as in Examples 1 & 2).
- the pulps were recovered immediately after the cold caustic extraction stage by slurrying the centrifuge pulp cake in water with recovery on a Buchner funnel and rinsing to remove excess caustic. This was followed by reslurrying and acidification with dilute sulfuric acid to pH 2.5-3.0, recovery in a Buchner funnel, and numerous water rinses prior to sheeting and drying.
- the 10% NaOH control sample (Example 5) was recovered in about a 90.2% yield from starting stock, while the 16% NaOH control sample (Example 6) was recovered in about a 88.6% yield.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Biochemistry (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Other Resins Obtained By Reactions Not Involving Carbon-To-Carbon Unsaturated Bonds (AREA)
- Paper (AREA)
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/943,650 US20030050472A1 (en) | 2001-08-31 | 2001-08-31 | Alkylene oxide modified hardwood cellulose |
EP02759438A EP1421119A4 (fr) | 2001-08-31 | 2002-08-23 | Cellulose de feuillu modifiee a l'oxyde d'alcoylene |
AU2002324773A AU2002324773A1 (en) | 2001-08-31 | 2002-08-23 | Alkylene oxide modified hardwood cellulose |
JP2003525708A JP2005527644A (ja) | 2001-08-31 | 2002-08-23 | アルキレンオキシド変性硬木材セルロース |
CA002459266A CA2459266A1 (fr) | 2001-08-31 | 2002-08-23 | Cellulose de feuillu modifiee a l'oxyde d'alcoylene |
MXPA04001577A MXPA04001577A (es) | 2001-08-31 | 2002-08-23 | Celulosa de madera dura modificada con oxido de alquileno. |
PCT/US2002/026860 WO2003021013A2 (fr) | 2001-08-31 | 2002-08-23 | Cellulose de feuillu modifiee a l'oxyde d'alcoylene |
US10/616,045 US6835828B2 (en) | 2001-08-31 | 2003-07-08 | Alkylene oxide modified hardwood cellulose |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/943,650 US20030050472A1 (en) | 2001-08-31 | 2001-08-31 | Alkylene oxide modified hardwood cellulose |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/616,045 Continuation US6835828B2 (en) | 2001-08-31 | 2003-07-08 | Alkylene oxide modified hardwood cellulose |
Publications (1)
Publication Number | Publication Date |
---|---|
US20030050472A1 true US20030050472A1 (en) | 2003-03-13 |
Family
ID=25480023
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/943,650 Abandoned US20030050472A1 (en) | 2001-08-31 | 2001-08-31 | Alkylene oxide modified hardwood cellulose |
US10/616,045 Expired - Lifetime US6835828B2 (en) | 2001-08-31 | 2003-07-08 | Alkylene oxide modified hardwood cellulose |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/616,045 Expired - Lifetime US6835828B2 (en) | 2001-08-31 | 2003-07-08 | Alkylene oxide modified hardwood cellulose |
Country Status (7)
Country | Link |
---|---|
US (2) | US20030050472A1 (fr) |
EP (1) | EP1421119A4 (fr) |
JP (1) | JP2005527644A (fr) |
AU (1) | AU2002324773A1 (fr) |
CA (1) | CA2459266A1 (fr) |
MX (1) | MXPA04001577A (fr) |
WO (1) | WO2003021013A2 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130303751A1 (en) * | 2010-09-17 | 2013-11-14 | Titan Wood Limited | Treatment of Wood Pieces |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101139400B (zh) * | 2006-09-08 | 2011-06-01 | 中国科学院过程工程研究所 | 秸秆乙酰化组分分离及制备秸秆醋酸纤维素的方法 |
KR20110123184A (ko) | 2010-05-06 | 2011-11-14 | 바히아 스페셜티 셀룰로스 에스에이 | 높은 알파 용해 펄프 제조를 위한 방법 및 시스템 |
CN109844208B (zh) | 2016-08-04 | 2021-10-29 | Pvh公司 | 免烫织物和服装及其整理方法 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2054746A (en) * | 1930-01-11 | 1936-09-15 | Soc Of Chemical Ind | Ethereal cellulose derivatives and process of making the same |
US2478425A (en) * | 1946-03-26 | 1949-08-09 | Eastman Kodak Co | Manufacture of cellulose acetate |
US3148106A (en) | 1964-01-29 | 1964-09-08 | Rayonier Inc | Pulp refining |
US4399275A (en) * | 1982-01-06 | 1983-08-16 | Itt Corporation | Preparation of highly reactive cellulose |
-
2001
- 2001-08-31 US US09/943,650 patent/US20030050472A1/en not_active Abandoned
-
2002
- 2002-08-23 MX MXPA04001577A patent/MXPA04001577A/es not_active Application Discontinuation
- 2002-08-23 AU AU2002324773A patent/AU2002324773A1/en not_active Abandoned
- 2002-08-23 WO PCT/US2002/026860 patent/WO2003021013A2/fr not_active Application Discontinuation
- 2002-08-23 EP EP02759438A patent/EP1421119A4/fr not_active Withdrawn
- 2002-08-23 CA CA002459266A patent/CA2459266A1/fr not_active Abandoned
- 2002-08-23 JP JP2003525708A patent/JP2005527644A/ja active Pending
-
2003
- 2003-07-08 US US10/616,045 patent/US6835828B2/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130303751A1 (en) * | 2010-09-17 | 2013-11-14 | Titan Wood Limited | Treatment of Wood Pieces |
US9151000B2 (en) * | 2010-09-17 | 2015-10-06 | Titan Wood Limited | Treatment of wood pieces |
Also Published As
Publication number | Publication date |
---|---|
JP2005527644A (ja) | 2005-09-15 |
WO2003021013A2 (fr) | 2003-03-13 |
EP1421119A4 (fr) | 2004-11-24 |
US6835828B2 (en) | 2004-12-28 |
EP1421119A2 (fr) | 2004-05-26 |
CA2459266A1 (fr) | 2003-03-13 |
MXPA04001577A (es) | 2005-03-07 |
AU2002324773A1 (en) | 2003-03-18 |
US20040106786A1 (en) | 2004-06-03 |
WO2003021013A3 (fr) | 2003-06-12 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: RAYONIER INC., FLORIDA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SEARS, KARL D.;HENDRICKS, WENDY;REEL/FRAME:012139/0543 Effective date: 20010830 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |