CN1240746C - Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst - Google Patents
Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst Download PDFInfo
- Publication number
- CN1240746C CN1240746C CN 200310101836 CN200310101836A CN1240746C CN 1240746 C CN1240746 C CN 1240746C CN 200310101836 CN200310101836 CN 200310101836 CN 200310101836 A CN200310101836 A CN 200310101836A CN 1240746 C CN1240746 C CN 1240746C
- Authority
- CN
- China
- Prior art keywords
- epoxysuccinic acid
- acid
- lime carbonate
- deionized water
- sodium hydroxide
- 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 - Fee Related
Links
Landscapes
- Epoxy Compounds (AREA)
Abstract
The present invention relates to a method for preparing polyeposysuecinic acid, which uses calcium carbonate as a catalyst. The present invention comprises the following operation steps: step 1, epoxy succinic acid is dissolved into deionized water, and the quality ratio of the epoxy succinic acid and the deionized water is 1; 1 to 1: 3; step 2, sodium hydroxide is added, the quality ratio of the epoxy succinic acid and the sodium hydroxide is 1: 0.1 to 1: 0.2, and epoxy succinic acid sodium is generated after alkalization by controlling the temperature to be lower than 80 DEG C; step 3, a calcium carbonate catalyst is added, and the quality ratio of the epoxy succinic acid and the calcium carbonate is 1: 0.02 to 1: 0.2. The temperature of polymerization reaction is 90 to 105 DEG C, the time of polymerization reaction is 3 to 6 hours, and then the crude product of polyeposysuecinic acid is produced. Then after filtration and refining operation, the polyeposysuecinic acid is obtained. The calcium carbonate catalyst has the advantages of no corrosion, no moisture absorption, no water solubility and difficult deterioration. The method has the advantages of stable reaction for synthesizing the polyeposysuecinic acid, short technical process, high product yield, easy product separation and high relative molecular mass.
Description
Technical field
The present invention relates to a kind of method by the synthetic polyepoxy sodium succinate of Epoxysuccinic acid, this method is to be catalyzer with lime carbonate.
Background technology
Poly-epoxy succinic acid is a kind of water-soluble polymers with powerful chelating and scale inhibition performance, and not phosphorous in its molecular structure, nitrogen element can not cause body eutrophication, and biological degradability is good, is a kind of green polymer.It is strong to calcium, magnesium, the isoionic chelating ability of iron, and has threshold effect, and scale inhibition performance is good, is applicable to high-alkali high solid water system, and high concentration multiple and zero blowdown are handled, and are the renewal products of existing Scale inhibitors.
The structural formula of the poly-epoxy succinic acid that United States Patent (USP) " polymers detergent builders " (US 3,776,850) proposes is:
Wherein R is H or other appointment group, and n is preferably 2-6 from 2-40.When n is 3 or 4, compound scale removal better performances.Its preparation method is to be that catalyzer is from the Epoxysuccinic acid monomer polymerization with the boron trifluoride.This method can be prepared the poly-epoxy succinic acid mixture of very low n=3 of content and n=4, but is difficult to realize industrialization.
United States Patent (USP) " Ether hydroxypolycarboxylate detergency builders " (US 4,654,159) proposes following structural formula:
In the formula, M is H, NH
4Or alkali metal cation, R is H or C
1-4Alkyl, n are more preferably 2～10 from 2～15, and preferably 2～4.Its preparation method is in liquid phase medium, the calcium hydroxide reaction that the epoxy succinic hydrochlorate of solubility is suitable with molar weight, and the reactant esterification separates ester from reaction mixture, the ester saponification is generated an alkali metal salt of poly-epoxy succinic acid again.The reaction conditions of epoxy succinic hydrochlorate and calcium hydroxide: will be equivalent to output at least 5%, preferably the epoxy succinic acid salt solution of 1/2 of 10%～80% mole calcium hydroxide amount adding pH value 5～7 is little, be heated to 100 ℃ and constant temperature 2h, the calcium hydroxide that adds all the other 1/2 amounts then is heated to 100 ℃ and constant temperature 2h.This method productive rate is higher, and synthetic product is effective to polyvalent cations such as chelating calcium, magnesium, and can be used as washing auxiliary detergent, to substitute phosphorus be auxiliary agent.But this method is strong as the calcium hydroxide corrodibility of catalyzer, easily moisture absorption and apt to deteriorate, and reaction product need pass through ion-exchange, esterification and processing such as carboxylate separation and saponification, and it is low etc. that the target product relative molecular mass is crossed.
Summary of the invention
The purpose of this invention is to provide a kind of method that with lime carbonate is catalyzer from the synthetic polyepoxy sodium succinate of Epoxysuccinic acid.Calcium carbonate catalyst has non-hygroscopic, the non-advantage such as water-soluble and not perishable of no burn into.This method is synthesized the polyepoxy sodium succinate reacting balance, and technical process is short, the product yield height, and product separation is easy, and relative molecular mass is higher.
The present invention is a kind of method that is catalyzer from the synthetic polyepoxy sodium succinate of Epoxysuccinic acid with lime carbonate.Comprise following operation steps:
(1) Epoxysuccinic acid is dissolved in the deionized water, the mass ratio of Epoxysuccinic acid and deionized water is 1: 1～1: 3;
(2) add sodium hydroxide, the mass ratio of Epoxysuccinic acid and sodium hydroxide is 1: 0.1～1: 0.2; Temperature is controlled at below 80 ℃ and generates epoxy sodium succinate through alkalization;
(3) add catalyzer carbonic acid calcium, the mass ratio of Epoxysuccinic acid and lime carbonate is 1: 0.02～1: 0.2; Polymeric reaction temperature is 90～105 ℃, and polymerization reaction time is 3～6h, promptly makes the polyepoxy sodium succinate crude product, the refining after filtration then polyepoxy sodium succinate that obtains.
The mass ratio of Epoxysuccinic acid of the present invention and deionized water is preferably 1: 2～and 1: 2.2.
The mass ratio of Epoxysuccinic acid of the present invention and sodium hydroxide is preferably 1: 0.15～and 1: 0.17.
The mass ratio of Epoxysuccinic acid of the present invention and lime carbonate is preferably 1: 0.05～and 1: 0.1.
The best temperature of polyreaction of the present invention is 90～100 ℃, and polymerization reaction time is 4h.
The mass ratio of Epoxysuccinic acid of the present invention and deionized water is 1: 1～1: 3, and the product solid content reduces during hypervolia, and operation was stable inadequately when the water yield was very few.The mass ratio of Epoxysuccinic acid and sodium hydroxide is 1: 0.1～1: 0.2, and amount of sodium hydroxide too much reduces with the very few product relative molecular mass that all can make.The temperature of reaction of Epoxysuccinic acid and sodium hydroxide is no more than 80 ℃, can cause the epoxy succinic acid hydrolysis when temperature is too high.The mass ratio of Epoxysuccinic acid and lime carbonate is 1: 0.02～1: 0.2, suitably reduces calcium carbonate quantity the product relative molecular mass is improved, but product yield is reduced when very few, and the product relative molecular mass is reduced.The adding temperature of lime carbonate without limits, preferably 70～100 ℃.The polymeric reaction temperature of Epoxysuccinic acid is 90～105 ℃ behind the adding catalyzer carbonic acid calcium, and preferably 90～100 ℃, polymerization reaction time is 4h.The polyepoxy sodium succinate of preparation adopts the gel chromatography relative molecular mass.The method that provides with invention can obtain product yield up to 100%, relative molecular mass is 300～1500 polyepoxy sodium succinate.The structural formula of the polyepoxy sodium succinate A that makes is:
Raw material Epoxysuccinic acid, lime carbonate and sodium hydroxide that the present invention uses can adopt commercially available technical grade product, calcium carbonate catalyst is compared with the calcium hydroxide catalyzer, lime carbonate has non-hygroscopic, the non-advantage such as water-soluble and not perishable of no burn into, lime carbonate adds alkali can not generate calcium hydroxide, is a kind of safer, stable catalyst more.With lime carbonate is that catalyzer synthesizes polyepoxy sodium succinate from Epoxysuccinic acid, reacting balance, and technical process is simple, the product yield height, the product relative molecular mass is higher.The polyepoxy sodium succinate of the inventive method preparation has threshold effect, is a kind of Scale inhibitors of excellent performance, and calcium ion is had very high tolerance, is applicable to that high-alkali high solid water is.
Embodiment
Embodiment 1: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4 in the polyepoxy sodium succinate structural formula～9).
Embodiment 2: under constantly stirring, 100g Epoxysuccinic acid, 15g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 3: under constantly stirring, 100g Epoxysuccinic acid, 17g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 4: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 200g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 5: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 220g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 6: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 60 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 7: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 80 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 8: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 70 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 9: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 100 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 10: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 5g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 600～1500 (being equivalent to n=5～12).
Embodiment 11: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 10g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 300～800 (being equivalent to n=2～7).
Embodiment 12: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 95 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 13: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 100 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 14: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 3.5h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 15: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 5h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1500 (being equivalent to n=4～12).
Embodiment 16: under constantly stirring, 100g Epoxysuccinic acid, 10g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 300～900 (being equivalent to n=2～8).
Embodiment 17: under constantly stirring, 100g Epoxysuccinic acid, 20g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 300～900 (being equivalent to n=2～8).
Embodiment 18: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 100g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 40%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 19: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 300g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 20%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 20: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 2g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 93%, solid content 30%, relative molecular mass 600～1500 (being equivalent to n=5～12).
Embodiment 21: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 20g, react 4h down at 98 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 300～800 (being equivalent to n=2～7).
Embodiment 22: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 90 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Embodiment 23: under constantly stirring, 100g Epoxysuccinic acid, 16g sodium hydroxide are added in the 217g deionized water, keep temperature of reaction to be no more than 65 ℃, get the Epoxysuccinic acid sodium solution, in the time of 80 ℃, add lime carbonate 7.6g, react 4h down at 105 ℃, remove by filter lime carbonate, promptly make polyepoxy sodium succinate, yield 100%, solid content 30%, relative molecular mass 400～1000 (being equivalent to n=4～9).
Claims (5)
1, a kind of is the polyepoxy sodium succinate preparation method of catalyzer with lime carbonate, comprises following operation steps:
(1) Epoxysuccinic acid is dissolved in the deionized water, the mass ratio of Epoxysuccinic acid and deionized water is 1: 1～1: 3;
(2) add sodium hydroxide, the mass ratio of Epoxysuccinic acid and sodium hydroxide is 1: 0.1～1: 0.2; Temperature is generating epoxy sodium succinate through alkalization below 80 ℃;
(3) add catalyzer carbonic acid calcium, the mass ratio of Epoxysuccinic acid and lime carbonate is 1: 0.02～1: 0.2; Polymeric reaction temperature is 90～105 ℃, and polymerization reaction time is 3～6h, promptly makes the polyepoxy sodium succinate crude product, the refining after filtration then polyepoxy sodium succinate that obtains.
2, method according to claim 1 is characterized in that: the mass ratio of Epoxysuccinic acid and deionized water is 1: 2～1: 2.2.
3, method according to claim 1 is characterized in that: the mass ratio of Epoxysuccinic acid and sodium hydroxide is 1: 0.15～1: 0.17.
4, method according to claim 1 is characterized in that: the mass ratio of Epoxysuccinic acid and lime carbonate is 1: 0.05～1: 0.1.
5, method according to claim 1 is characterized in that: polymeric reaction temperature is 90～100 ℃, and polymerization reaction time is 4h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200310101836 CN1240746C (en) | 2003-10-20 | 2003-10-20 | Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200310101836 CN1240746C (en) | 2003-10-20 | 2003-10-20 | Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1609132A CN1609132A (en) | 2005-04-27 |
| CN1240746C true CN1240746C (en) | 2006-02-08 |
Family
ID=34756261
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200310101836 Expired - Fee Related CN1240746C (en) | 2003-10-20 | 2003-10-20 | Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1240746C (en) |
-
2003
- 2003-10-20 CN CN 200310101836 patent/CN1240746C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1609132A (en) | 2005-04-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1096436C (en) | Cement additives | |
| EP2180004B1 (en) | Olefinically unsaturated phosphonate compounds, polymers made therefrom and their use | |
| US5312967A (en) | Process for making activated aldarate esters, ester/lactones and lactones | |
| CN109133389B (en) | Non-phosphorus composite scale inhibitor | |
| CN1699338A (en) | Thiosulfuric acid derivant preparation | |
| CN102146161A (en) | Polyaspartic acid complex for scale inhibitor | |
| CN1724447A (en) | Water reducing agent of poly carboxylic acid series concrete and its preparation process | |
| CN1733687A (en) | A (methyl) higher aliphatic acrylate preparation method | |
| FR2892420A1 (en) | New polymer having a principal hydrocarbon chain and phosphonated and polyoxyalkylated lateral groups useful e.g. to liquefy mineral particle suspension, particularly cement composition | |
| CN1240745C (en) | Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst | |
| CN1240746C (en) | Prepn process of polyepoxy succinic acid with calcium sulfate as catalyst | |
| CN1314614C (en) | Concrete water reducing agent of polycarboxylic acid and its prepn process | |
| CN1132859C (en) | Process for suspension polymerization of vinyl chloride | |
| CN1636921A (en) | Concrete water reducing agent of polyacrylic acid and its synthesis process | |
| US5519102A (en) | Aqueous polymerization method for poly(isopropenylphosphonic acid) | |
| EP2753600A1 (en) | Vinyl monomers having chelating functionality | |
| CN1830986A (en) | Method for preparing ammonium salts of cyclohexanpentol phosphate ester | |
| FI57118B (en) | SAMPOLYMER AV AKRYLSYRA VILKA AER ANVAENDBARA SAOSOM KOMPLEXBILDARE OCH / ELLER SEQUENTING SEED FOR OVER FLERVAERDA METAL IONER OCH FOERFARANDE FOER DERAS FRAMSTAELLNING | |
| RU2618220C2 (en) | Method for polyester convertion to polymeric acid | |
| EA027033B1 (en) | Process for preparing cyclic diesters, especially dilactide | |
| CN110845664A (en) | Calcium carbonate scale inhibitor and preparation method thereof | |
| CN109970572B (en) | Synthetic method of double-bond end-capping compound | |
| US4233423A (en) | Stabilization of polymeric acetal carboxylates using an acetal | |
| US4201858A (en) | Method of preparing polyacetal carboxylates | |
| JPH0617383B2 (en) | Method for producing hydrolyzed polymaleic anhydride |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |