Patent US3839319A successfully refreshed from Google Patents.
US3839319A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydroxypropyl methylcellulose ethers and method of preparation
Assignee: Dow Chemical Co
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Filing: 1973-01-26
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Granted: 1974-10-01
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Expires: 1993-01-26
Abstract
Abstract Novel hydroxypropyl methylcellulose ethers have a methoxyl degree of substitution of from 0.2 to 1.0 and a hydroxypropyl molar substitution of at least about 1.5 with a total combined degree of substitution of at least about 1.8. These ethers have desirable solubility properties in anhydrous organic solvents such as methanol and ethanol and can be employed as thickeners and film formers. They are prepared by concurrent reaction of controlled proportions of methyl chloride and propylene oxide with alkali cellulose.
Inventors
- 👤 G Greminger
- 👤 J Hudson
- 👤 C Strange
- 👤 K Krumel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:22
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/193
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
141 words
A PROCESS FOR PREPARING HYDROXYPROPYL METHYLCELLULOSE ETHER, SOLUBLE IN COLD WATER AND IN ANHYDROUS METHANOL, WHICH COMPRISES THE STEPS OF PREPARING ALKALI CELLULOSE BY REACTING CELLULOSE WITH A CONCENTRATED SODIUM HYDROXIDE SOLUTION IN AMOUNT TO PROVIDE FROM ABOUT 0.25 TO ABOUT 0.45 PART BY WEIGHT OF SODIUM HYDROXIDE PER PART BY WEIGHT OF CELLULOSE AND REACTING SAID ALKALI CELLULOSE WITH A MIXTURE CONTANING, FROM ABOUT 1.5 TO 4 PARTS OF PROPYLENE OXIDE AND FROM 0.4 TO ABOUT 0.8 PART OF METHYL CHLORIDE PER PART BY WEIGHT OF CELLULOSE IN THE ALKALI CELLULOSE, THE AMOUNTS OF PROPYLENE OXIDE AND METHYL CHLORIDE EMPLOYED IN THE TOTAL REACTION BEING ADJUSTED TO PROVIDE AT LEAST 1 MOLE OF METHYL CHLORIDE FOR EACH MOLE OF SODIUM HYDROXIDE INCORPORATED IN THE ALKALI CELLULOSE AND AT LEAST 2 MOLES OF PROPYLENE OXIDE PER MOLE OF METHYL CHLORIDE EMPLOYED.
Claim 2
Dependent Claim
141 words
A PROCESS FOR PREPARING HYDROXYPROPYL METHYLCELLULOSE ETHER, SOLUBLE IN COLD WATER AND IN ANHYDROUS METHANOL, WHICH COMPRISES THE STEPS OF PREPARING ALKALI CELLULOSE BY REACTING CELLULOSE WITH A CONCENTRATED SODIUM HYDROXIDE SOLUTION IN AMOUNT TO PROVIDE FROM ABOUT 0.25 TO ABOUT 0.45 PART BY WEIGHT OF SODIUM HYDROXIDE PER PART BY WEIGHT OF CELLULOSE AND REACTING SAID ALKALI CELLULOSE WITH A MIXTURE CONTANING, FROM ABOUT 1.5 TO 4 PARTS OF PROPYLENE OXIDE AND FROM 0.4 TO ABOUT 0.8 PART OF METHYL CHLORIDE PER PART BY WEIGHT OF CELLULOSE IN THE ALKALI CELLULOSE, THE AMOUNTS OF PROPYLENE OXIDE AND METHYL CHLORIDE EMPLOYED IN THE TOTAL REACTION BEING ADJUSTED TO PROVIDE AT LEAST 1 MOLE OF METHYL CHLORIDE FOR EACH MOLE OF SODIUM HYDROXIDE INCORPORATED IN THE ALKALI CELLULOSE AND AT LEAST 2 MOLES OF PROPYLENE OXIDE PER MOLE OF METHYL CHLORIDE EMPLOYED.
Claim 3
Dependent Claim
41 words
A process according to claim 1 wherein 0.35 to 0.4 part of sodium hydroxide, 1.5 to 2 parts of propylene oxide and 0.6 to 0.8 part of methyl chloride are employed per part by weight of cellulose in the reaction mixture.
Claim 4
Dependent Claim
49 words
A process according to claim 1 wherein the alkali cellulose and the mixture of propylene oxide and methyl chloride are combined at ambient temperature and heated with thorough agitation to a temperature of from about 50*C. to about 75*C. for a period of time to complete the etherification reaction.
Claim 5
Dependent Claim
46 words
A process according to claim 3 wherein a major proportion of the methyl chloride is introduced along with the propylene oxide at the initiation of the reaction and the remainder of the methyl chloride is introduced after the initial reaction of propylene oxide is substantially completed.
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |