US3976824A
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US
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Treating agent useful for fibrous materials and preparation thereof
Assignee: Arakawa Rinsan Kagaku Kogyo KK
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Filing: 1975-06-03
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Granted: 1976-08-24
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Expires: 1995-06-03
Abstract
Abstract Amide-containing cationic copolymer is reacted with polyalkyleneimine in an aqueous medium to form a water-soluble cationic resin which is a treating agent useful for fibrous materials. The adduct of halohydrin to water-soluble cationic resin is a water-soluble cationic thermosetting resin and is also useful for treating fibrous materials. The treating agent has excellent retention ability to fiber, drainage property and storage stability and remarkably improves the retention of fillers and wet and dry strength of paper.
Inventors
- 👤 Junji Ariyoshi
- 👤 Akira Ohnishi
- 👤 Hiromi Toda
- 👤 Kametaro Kunimori
- 👤 Mitsuyoshi Nakao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:06
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/33; D21H17/34; D21H17/41; D21H17/44; D21H17/45; D21H17/455; C; C08; C08F; C08F8/00; C08F8/08; C08F8/30; C08F2800/00; C08F2800/10; C08F2800/20; C08F2810/00; C08F2810/20
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
482 words
A treating agent useful for fibrous materials which comprises A. a reaction product of (a) an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof and (b) a polyalkyleneimine having a degree of polymerization of not less than 20, or B. a reaction product of the above ingredients (a) and (b) and (c) a halohydrin selected from the group consisting of epichlorohydrin, epibromohydrin, monochlorohydrin, monobromohydrin, dichlorohydrin and dibromohydrin; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU17## wherein R 1 is hydrogen or methyl group, ii. 3 to 70 % by mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU18## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU19## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU20## wherein R 7 is hydrogen or methyl group; ##SPC4## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU21## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU22## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU23## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU24## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU25## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of --COOR 20 , --CN, ##SPC5## ##EQU26## and -CONHR 24 and wherein, R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU27##
Claim 2
Dependent Claim
482 words
A treating agent useful for fibrous materials which comprises A. a reaction product of (a) an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof and (b) a polyalkyleneimine having a degree of polymerization of not less than 20, or B. a reaction product of the above ingredients (a) and (b) and (c) a halohydrin selected from the group consisting of epichlorohydrin, epibromohydrin, monochlorohydrin, monobromohydrin, dichlorohydrin and dibromohydrin; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU17## wherein R 1 is hydrogen or methyl group, ii. 3 to 70 % by mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU18## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU19## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU20## wherein R 7 is hydrogen or methyl group; ##SPC4## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU21## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU22## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU23## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU24## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU25## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of --COOR 20 , --CN, ##SPC5## ##EQU26## and -CONHR 24 and wherein, R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU27##
Claim 3
Dependent Claim
29 words
The treating agent of claim 1, wherein said amide-containing cationic copolymer has a viscosity of 50 to 200,000 cP at 25°C. in 10 % by weight aqueous solution thereof.
Claim 4
Dependent Claim
74 words
The treating agent of claim 1, wherein said amide-containing cationic copolymer is one prepared by copolymerizing a monomer mixture consisting of 50 to 95 % by mole of at least one monomer having the general formula (1), 5 to 50 % by mole of at least one cationic monomer having the general formulae (1) to (9) or their salts, and 0 to 40 % by mole of a monomer having the general formula (10).
Claim 5
Dependent Claim
185 words
The treating agent of claim 1, wherein said amide-containing cationic copolymer is one prepared by employing as the cationic monomer at least one member selected from the group consisting of monomers having the following formulae or their salts: ##EQU28## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU29## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU30## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl, group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; and ##EQU31## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group.
Claim 6
Dependent Claim
23 words
The treating agent of claim 1, wherein said salt of the cationic monomer is an acid addition salt or a quaternary ammonium salt.
Claim 7
Dependent Claim
18 words
The treating agent of claim 1, wherein said polyalkyleneimine has a degree of polymerization of 100 to 5,000.
Claim 8
Dependent Claim
11 words
The treating agent of claim 1, wherein said polyalkyleneimine is polyethyleneimine.
Claim 9
Dependent Claim
36 words
The treating agent of claim 1, wherein molar ratio of amide group in said amide-containing cationic copolymer to total monomer unit in said polyalkyleneimine falls within the range of 95 : 5 to 10 : 90.
Claim 10
Dependent Claim
36 words
The treating agent of claim 1, wherein molar ratio of amide group in said amide-containing cationic copolymer to total monomer unit in said polyalkyleneimine falls within the range of 90 : 10 to 20 : 80.
Claim 11
Dependent Claim
34 words
The treating agent of claim 1, wherein molar ratio of said halohydrin to amino group in said amide-containing cationic copolymer and polyalkyleneimine falls within the range of 0.5 : 1 to 3 : 1.
Claim 12
Dependent Claim
34 words
The treating agent of claim 1, wherein molar ratio of said halohydrin to amino group in said amide-containing cationic copolymer and polyalkyleneimine falls within the range of 1 : 1 to 2.5 : 1.
Claim 13
Dependent Claim
491 words
A process for preparing a treating agent which comprises subjecting an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof and polyalkyleneimine having a degree of polymerization of not less than 20 to deammonification condensation in an aqueous medium at pH 6 to 10 at a temperature of 20° to 100°C. in a molar ratio of amide group in said amide-containing cationic copolymer to amino group in said polyalkyleneimine of from 95 : 5 to 10 : 90; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU32## wherein R 1 is hydrogen or methyl group, ii. 3 to 70 % mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU33## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU34## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU35## wherein R 7 is hydrogen or methyl group; ##SPC6## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU36## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU37## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU38## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU39## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU40## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of -COOR 20 , -CN, ##SPC7## ##EQU41## and -CONHR 24 and wherein R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU42##
Claim 14
Dependent Claim
491 words
A process for preparing a treating agent which comprises subjecting an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof and polyalkyleneimine having a degree of polymerization of not less than 20 to deammonification condensation in an aqueous medium at pH 6 to 10 at a temperature of 20° to 100°C. in a molar ratio of amide group in said amide-containing cationic copolymer to amino group in said polyalkyleneimine of from 95 : 5 to 10 : 90; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU32## wherein R 1 is hydrogen or methyl group, ii. 3 to 70 % mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU33## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU34## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU35## wherein R 7 is hydrogen or methyl group; ##SPC6## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU36## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU37## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU38## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU39## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU40## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of -COOR 20 , -CN, ##SPC7## ##EQU41## and -CONHR 24 and wherein R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU42##
Claim 15
Dependent Claim
528 words
A process for preparing a treating agent which comprises reacting an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof, polyalkyleneimine having a degree of polymerization of not less than 20 and a halohydrin selected from the group consisting of epichlorohydrin, epibromohydrin, monochlorohydrin, monobromohydrin, dichlorohydrin and dibromohydrin in an aqueous medium at pH 6 to 10 at a temperature of 20° to 100°C. in a molar ratio of amide group in said amide-containing cationic copolymer to total monomer unit in said polyalkyleneimine of from 95 : 5 to 10 : 90 and in a molar ratio of said halohydrin to total monomer unit in said polyalkyleneimine of from 0.5 : 1 to 3 : 1,; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU43## wherein R 1 is hydrogen or methyl group, ii. 3 to 70% by mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU44## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU45## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU46## wherein R 7 is hydrogen or methyl group; ##SPC8## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU47## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU48## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU49## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU50## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU51## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of --COOR 20 , --CN, ##SPC9## ##EQU52## and -CONHR 24 and wherein R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU53##
Claim 16
Dependent Claim
528 words
A process for preparing a treating agent which comprises reacting an amide-containing cationic copolymer having a viscosity of 10 to 2,000,000 cP at 25°C. in 10 % by weight aqueous solution thereof, polyalkyleneimine having a degree of polymerization of not less than 20 and a halohydrin selected from the group consisting of epichlorohydrin, epibromohydrin, monochlorohydrin, monobromohydrin, dichlorohydrin and dibromohydrin in an aqueous medium at pH 6 to 10 at a temperature of 20° to 100°C. in a molar ratio of amide group in said amide-containing cationic copolymer to total monomer unit in said polyalkyleneimine of from 95 : 5 to 10 : 90 and in a molar ratio of said halohydrin to total monomer unit in said polyalkyleneimine of from 0.5 : 1 to 3 : 1,; said amide-containing cationic copolymer being prepared by copolymerizing a monomer mixture consisting of i. 30 to 97 % by mole of at least one monomer having the following formula: ##EQU43## wherein R 1 is hydrogen or methyl group, ii. 3 to 70% by mole of at least one cationic monomer selected from the group consisting of monomers having the following formulae or their salts: ##EQU44## wherein R 2 is hydrogen or methyl group, and R 3 and R 4 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU45## wherein R 5 is hydrogen or methyl group, and R 6 is hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group; ##EQU46## wherein R 7 is hydrogen or methyl group; ##SPC8## wherein R 8 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU47## wherein R 9 is hydrogen or an alkyl group having 1 to 4 carbon atoms; ##EQU48## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU49## wherein R 13 is hydrogen or methyl group, R 14 and R 15 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group; ##EQU50## wherein R 16 is an alkyl group having 1 to 4 carbon atoms, R 17 and R 18 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group, and iii. 0 to 40 % by mole of a monomer having the following formula: ##EQU51## wherein R 19 is hydrogen or methyl group and X is a member selected from the group consisting of --COOR 20 , --CN, ##SPC9## ##EQU52## and -CONHR 24 and wherein R 20 is hydrogen, an alkyl group having 1 to 8 carbon atoms, glycidyl group or a hydroxyalkyl group having 2 to 4 carbon atoms, R 21 , R 22 and R 23 are independently hydrogen, methyl group or ethyl group and R 24 is a hydroxyalkyl group having 1 to 2 carbon atoms or ##EQU53##
Claim 17
Dependent Claim
53 words
The process of claim 13, wherein said amide-containing cationic copolymer is reacted with said polyalkyleneimine at pH 6 to 10 at a temperature of 20° to 100°C. to form a condensate and the resulting condensate is then reacted with said halohydrin at pH 4 to 10 at a temperature of 20° to 100°C.
Claim 18
Dependent Claim
44 words
A process for preparing fibrous materials which comprises forming a sheet in an aqueous medium at pH 3 to 10 in the presence of 0.05 to 1010 by weight (calculated as a non-volatile material) of a treating agent according to claim 1 to fiber.
Claim 19
Dependent Claim
18 words
The process of claim 15, wherein said treating agent is the reaction product (A) according to claim 1.
Claim 20
Dependent Claim
18 words
The process of claim 15, wherein said treating agent is the reaction product (B) according to claim 1.
Claim 21
Dependent Claim
12 words
The process of claim 15, wherein said fiber is a vegetable fiber.
Claim 22
Dependent Claim
11 words
The process of claim 18, wherein said vegetable fiber is pulp.
Claim 23
Dependent Claim
81 words
The treating agent of claim 4, wherein said amide-containing cationic copolymer is one prepared by employing as the cationic monomer at least one member selected from the group consisting of monomers having the following formula or their salts: ##EQU54## wherein R 10 is hydrogen or methyl group, R 11 and R 12 are independently hydrogen, an alkyl group having 1 to 6 carbon atoms, 2-hydroxyethyl group or benzyl group, and A is ethylene group, trimethylene group, tetramethylene group or 2-hydroxytrimethylene group.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |