Patent US7022837B2 successfully refreshed from Google Patents.
US7022837B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cellulose ethers and method of preparing the same
Assignee: BUCKEYE SPECIALTY FIBERS HOLDINGS LLC
•
Filing: 2001-10-31
•
Granted: 2006-04-04
•
Expires: 2021-10-31
Abstract
Abstract The present inventors have discovered that the solution rheology of cellulose ethers prepared from cellulose pulp is altered by mercerizing and recovering cellulose pulp before preparing the cellulose ethers. For example, the solution viscosity of carboxymethyl cellulose (CMC) produced from mercerized and recovered cellulose pulp is significantly greater than that produced from non-mercerized cellulose pulp. The present invention provides a method of preparing cellulose ethers comprising the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) converting the mercerized and recovered cellulose pulp into the cellulose ethers. According to one embodiment, the cellulose pulp is southern softwood kraft and the mercerized cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP. This method, however, may be applied to all cellulose pulps, regardless of their viscosities, including those which, when mercerized, have a viscosity greater than 12 cP. The mercerized cellulose pulp is typically substantially free of cellulose III. Mercerized cellulose pulp prepared by this method has a greater percentage of crystalline cellulose II and a smaller crystalline area than that of non-mercerized cellulose pulp. The present invention also provides a method of preparing a cellulose floc comprising the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) treating the mercerized pulp to form the cellulose floc. Alternatively, the method comprises mercerizing and recovering a cellulose floc. Cellulose floc prepared by this method have a greater bulk density than cellulose floc prepared from similar non-mercerized cellulose pulp. Furthermore, the bulk density gain is greater than that expected from the coarseness (weight per unit of fiber length) gain from preparing a cellulose floc.
Inventors
- 👤 Roger Bruce Harding
- 👤 Susan L. H. Crenshaw
- 👤 Paul Eugene Gregory
- 👤 Denise Hartnett Broughton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:09
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B1/00; C08B1/06; C08B1/08; C08B11/10; C08B11/12
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
66 words
A carboxymethyl cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into carboxymethyl cellulose, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 2
Dependent Claim
66 words
A carboxymethyl cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into carboxymethyl cellulose, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 3
Dependent Claim
66 words
A methyl cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into methyl cellulose, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 4
Dependent Claim
66 words
A methyl cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into methyl cellulose, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 5
Dependent Claim
151 words
A nonionic cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into a nonionic cellulose ether, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP, and when the cellulose ether prepared is hydroxyethyl cellulose, the mercerized and recovered cellulose pulp has at least one of the following properties: (i) a TAPPI 230 om-89 viscosity less than 10.4 cP or greater than 11.2 cP, (ii) a solubility in 10% sodium hydroxide as determined by ASTM D 1696-95 of greater than 2.3%, (iii) a solubility in 18% sodium hydroxide as determined by ASTM D 1696-95 of greater than 1.3%, (iv) not been prehydrolyzed, or (v) not been bleached with elemental chlorine.
Claim 6
Dependent Claim
151 words
A nonionic cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into a nonionic cellulose ether, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP, and when the cellulose ether prepared is hydroxyethyl cellulose, the mercerized and recovered cellulose pulp has at least one of the following properties: (i) a TAPPI 230 om-89 viscosity less than 10.4 cP or greater than 11.2 cP, (ii) a solubility in 10% sodium hydroxide as determined by ASTM D 1696-95 of greater than 2.3%, (iii) a solubility in 18% sodium hydroxide as determined by ASTM D 1696-95 of greater than 1.3%, (iv) not been prehydrolyzed, or (v) not been bleached with elemental chlorine.
Claim 7
Dependent Claim
68 words
An ionic cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into an ionic cellulose ether, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 8
Dependent Claim
68 words
An ionic cellulose ether prepared by: (a) obtaining mercerized and recovered cellulose pulp; and (b) converting the mercerized and recovered cellulose pulp into an ionic cellulose ether, wherein the mercerized cellulose pulp in step (a) was mercerized with a cellulose II mercerizing agent, the cellulose pulp is southern softwood kraft, and the mercerized and recovered cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 9
Dependent Claim
56 words
A cellulose floc prepared by: (a) obtaining mercerized and recovered cellulose pulp, and (b) treating the mercerized pulp to form a cellulose floc, wherein the cellulose pulp is southern softwood kraft and the mercerized and recovered cellulose pulp is substantially free of cellulose III and has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 10
Dependent Claim
56 words
A cellulose floc prepared by: (a) obtaining mercerized and recovered cellulose pulp, and (b) treating the mercerized pulp to form a cellulose floc, wherein the cellulose pulp is southern softwood kraft and the mercerized and recovered cellulose pulp is substantially free of cellulose III and has a TAPPI 230 om-89 viscosity of at most 12 cP.
Claim 11
Dependent Claim
40 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having at least about 20% by weight of cellulose II, based upon 100% total weight of the crystalline portion of the mercerized cellulose pulp.
Claim 12
Dependent Claim
40 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having at least about 20% by weight of cellulose II, based upon 100% total weight of the crystalline portion of the mercerized cellulose pulp.
Claim 13
Dependent Claim
38 words
The cellulose ether of claim 6 , wherein the mercerized and recovered cellulose pulp comprises at least about 35% by weight of cellulose II, based upon 100% total weight of the crystalline portion of the mercerized cellulose pulp.
Claim 14
Dependent Claim
38 words
The cellulose ether of claim 7 , wherein the mercerized and recovered cellulose pulp comprises at least about 60% by weight of cellulose II, based upon 100% total weight of the crystalline portion of the mercerized cellulose pulp.
Claim 15
Dependent Claim
24 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having an Rx value of greater than 0.57.
Claim 16
Dependent Claim
24 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having an Rx value of greater than 0.57.
Claim 17
Dependent Claim
22 words
The cellulose ether of claim 9 , wherein the mercerized and recovered cellulose pulp has an Rx value of greater than 0.60.
Claim 18
Dependent Claim
22 words
The cellulose ether of claim 10 , wherein the mercerized and recovered cellulose pulp has an Rx value of greater than 0.64.
Claim 19
Dependent Claim
25 words
The cellulose ether of claim 6 or of claim 9 , wherein the cellulose ether is an ionic cellulose ether or a nonionic cellulose ether.
Claim 20
Dependent Claim
38 words
The cellulose ether of claim 12 , wherein the cellulose ether is a carboxymethyl cellulose, a hydroxyethyl cellulose, a hydroxypropyl cellulose, a methyl hydroxyethyl cellulose, an ethyl hydroxyethyl cellulose, a methyl cellulose, or a methyl hydroxy propyl cellulose.
Claim 21
Dependent Claim
15 words
The cellulose ether of claim 13 , wherein the cellulose ether is a carboxymethyl cellulose.
Claim 22
Dependent Claim
15 words
The cellulose ether of claim 13 , wherein the cellulose ether is a hydroxyethyl cellulose.
Claim 23
Dependent Claim
35 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having a total crystallinity of less than about 60% by weight, based on 100% weight of total cellulose pulp.
Claim 24
Dependent Claim
35 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp having a total crystallinity of less than about 60% by weight, based on 100% weight of total cellulose pulp.
Claim 25
Dependent Claim
33 words
The cellulose ether of claim 16 , wherein the mercerized and recovered cellulose pulp has a total crystallinity of less than about 45% by weight, based on 100% weight of total cellulose pulp.
Claim 26
Dependent Claim
36 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp comprising less than 20% by weight of moisture content, based upon 100% total weight of mercerized and recovered cellulose pulp.
Claim 27
Dependent Claim
36 words
A cellulose ether derived from mercerized and recovered cellulose pulp, the mercerized and recovered cellulose pulp comprising less than 20% by weight of moisture content, based upon 100% total weight of mercerized and recovered cellulose pulp.
Claim 28
Dependent Claim
56 words
A cotton linters pulp derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density CLP Floc =m *( AFL ) −0.8043 wherein m ranges from 0.0755 to 0.0835 and AFL is the number average floc length of the cellulose floc.
Claim 29
Dependent Claim
56 words
A cotton linters pulp derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density CLP Floc =m *( AFL ) −0.8043 wherein m ranges from 0.0755 to 0.0835 and AFL is the number average floc length of the cellulose floc.
Claim 30
Dependent Claim
56 words
A southern softwood kraft derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density SSK Floc =m *( AFL ) −0.9676 wherein m ranges from 0.0841 to 0.0925 and AFL is the number average floc length of the cellulose floc.
Claim 31
Dependent Claim
56 words
A southern softwood kraft derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density SSK Floc =m *( AFL ) −0.9676 wherein m ranges from 0.0841 to 0.0925 and AFL is the number average floc length of the cellulose floc.
Claim 32
Dependent Claim
56 words
A northern softwood sulfite derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density NSS Floc =m *( AFL ) −0.7336 wherein m ranges from 0.0689 to 0.0758 and AFL is the number average floc length of the cellulose floc.
Claim 33
Dependent Claim
56 words
A northern softwood sulfite derived cellulose floc having an average floc length of from 0.25 to 0.50 mm and a floc tap density according to the formula: Floc Tap Density NSS Floc =m *( AFL ) −0.7336 wherein m ranges from 0.0689 to 0.0758 and AFL is the number average floc length of the cellulose floc.
References Cited (Backward Citations)
DE148342C
Cited
DE146462C
Cited
US1415023A
Cited
US1704304A
Cited
US1854331A
Cited
US1860432A
Cited
US1938360A
Cited
US2038678A
Cited
US2090808A
Cited
US2067946A
Cited
US2241397A
Cited
US2228127A
Cited
US2488631A
Cited
US2687352A
Cited
US2636879A
Cited
US3131177A
Cited
US3131176A
Cited
US3284441A
Cited
US3322748A
Cited
US3457047A
Cited
US3652539A
Cited
US3926951A
Cited
US4001211A
Cited
US4063018A
Cited
SU737404A1
Cited
US4096326A
Cited
US4084060A
Cited
US4250305A
Cited
US4269859A
Cited
US4292426A
Cited
US4339573A
Cited
SU952853A1
Cited
SU1028676A1
Cited
US4460766A
Cited
US4399275A
Cited
US4508895A
Cited
US4526961A
Cited
US4491661A
Cited
US4508894A
Cited
US4507474A
Cited
US4547570A
Cited
US4661589A
Cited
US4820813A
Cited
US5013832A
Cited
US4941943A
Cited
US4845206A
Cited
EP0390240A1
Cited
US5140099A
Cited
JPH032201A
Cited
US5476668A
Cited
EP0539979A2
Cited
US5385607A
Cited
US5550189A
Cited
US5410034A
Cited
US5858021A
Cited
EP0879827A2
Cited
WO2000032637A1
Cited
WO2000039390A1
Cited
WO2000065145A1
Cited
US6686464B1
Cited
WO2000071586A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2009-04-03 | 2009-10-03 | 2010-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2013-04-03 | 2013-10-03 | 2014-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2017-04-03 | 2017-10-03 | 2018-04-04 | $7700.00 | Window Closed / Lapsed |