CA1148438A - Use of acrylic acid/sodium vinyl-sulfonate copolymers as dispersants in boiler applications - Google Patents
Use of acrylic acid/sodium vinyl-sulfonate copolymers as dispersants in boiler applicationsInfo
- Publication number
- CA1148438A CA1148438A CA000377477A CA377477A CA1148438A CA 1148438 A CA1148438 A CA 1148438A CA 000377477 A CA000377477 A CA 000377477A CA 377477 A CA377477 A CA 377477A CA 1148438 A CA1148438 A CA 1148438A
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- CA
- Canada
- Prior art keywords
- acrylic acid
- copolymer
- alkali metal
- vinylsulfonate
- molecular weight
- 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
Links
Abstract
ABSTRACT OF THE DISCLOSURE
Copolymers of acrylic acid, or the alkali metal or ammonium salts thereof, and alkali metal vinylsulfonate find great utility as dispersants and stabilizers for finely divided inorganic scale-forming constituents in industrial water systems, particularly as additives to boiler water. The polymers have a molecular weight of from 750 to 50,000.
Copolymers of acrylic acid, or the alkali metal or ammonium salts thereof, and alkali metal vinylsulfonate find great utility as dispersants and stabilizers for finely divided inorganic scale-forming constituents in industrial water systems, particularly as additives to boiler water. The polymers have a molecular weight of from 750 to 50,000.
Description
Certain polymeric materials have proven over the years to give great utility as dispersants in industrial water systems.
~inding utility in boiler water, cooling water, and other industrial process applications, the polymers have been employed to keep metallic surfaces in contact with process water substantially free of mineral scale in these and other industrial applications.
Examples of prior art water soluble polymer dlspersants include the use of a maleic anhydride-vinyl acetate copolymer. United States Patent No. 3,444,054 shows the utilization of polymethacrylic acid. United States Patent No. 3,682,22~ to sleyle shows the use of methacrylic acid-vinyl sulfonate copolymers to disperse scale in water handling systems. Other materials whlch have been used in application of these types include polyacrylic acid, sulfonated starch derivatives and various copolymers of acrylic acid with other comonomers including acrylamide, methacrylamide, methylacrylate, etc. These polymeric materials oveTall are used in the water system at levels so as to cause the complete dispersion of scale-forming constituents and thus render the heat transfer surfaces contacting the water more efficient.
This invention contemplates the use o~ specific copolymers of acrylic acid and/or its alkali metal or ammonium salts with an alkali metal vinylsulfonate. These materia~ when prepared in the manner described, give superior activity in reducing the scale on heat transfer surfaces. These polymers are believed to be unique in their high activity to dispersing inorganic scale forming constituents found in industrially used waters.
Thus this invention seeks to provide to the art an acrylic ; acid-alkali metal vinylsul~onate copolymer useful as an additive to prevent scale formation in industrial water systems.
This invention also seeks to provide ~ 1 _ ., . .
a copolymer of acrylic acid - sodium vinylsulfonate, the copolymer having a mole ratio of acrylic acid to sodium ~inylsulfonate of from 90:10 to 60:40, the polymer having a molecular weight in the range of 1,000 - 60,000.
Additionally, this invention seeks to provide a composition including an acrylic acid - sodium vinylsulfonate copolymer for use in industrial water systems and particular]y in industrial boiler water.
THE COh~OSITION
As detailed abo~e, the composition of this invention is a copolymer of acrylic acid and an alkali metal vinylsulfonate The term acrylic acid as used in this in~ention also includes the alkali metal salts of acrylic acid, such as the sodium and/or potassium forms, as well as the ammonium salt. The vinylsulfonate employed is generally utilized as an alkali metal salt from the group consisting of sodium and/or potassium. Due to cost considerations, the sodium salt form is preferred. Vinyl sulfonic acid may also be used.
The composition of this invention generally con~ains from lQ-90 mole percent o acrylic acid or its water soluble salts.
Perferably, the composition of the instant invention contains from 85-35 mole percent of acrylic acid or its water soluble salt and most preferably from 80-60 mole percent of acrylic acid or its water soluble salts.
Polymer of acry~lic aci`d and sodium vinylsulfonate can be prepared by ~ell known conventional solution polymerization techniques.
~enerally these materials are prepared from 10-50 and more preferably 15-35 percent aqueous polymer solutions. The molecular weight of the polymers useful in this invention may range from as low as 500 to as high as 150,000. Preferably the molecular weight range will ~ary from 75Q to approximately 50,000 and most preferably from 900 to 15,000.
" .
ldeally the polymer has a molecular weight o~ ~rom 1,000 to 6JOOO.
It is important in selecting the polymers for use in thls invention that they remain completely water soluble. The polymers of the instant invention may be pr0pared in a variety of ways.
~ethod o preparation is unimportant so long as a polymer satisfying the requirements stated above is obtained. The polymers accordingly may be produced in aqueous solution utilizing conventional red-ox catalysts, water soluble peroxicde catalysts or the like.
The polymers may be made by batch process or by adding the acrylic acid monomer in the presence of a catalyst to an aqueous soltuion of the vinylsulfonate monomer at a specified polymeriza~ion temperature.
As stated above, the copolymer o~ the instant invention find great utility as polymeric dispersants for inorganic scale forming constituents found in industrial water handling systems.
These systems, such as both once-through and re-circulating industrial : cooling water systems, boiler water systems and the like where water is concentrated to relatively high levels of dissolved solids, lend themselves to the applicability of the use of the polymers of the instant invention. The polymers of the instant invention have been found to be particularly useful in industrial boiler water as scale dispersants.
rn typical applications of the polymers of the instant inven-tion they are utilized at levels sufficient to disperse any suspended solids present in the water system. Generally, small amoun~ of the polymeric solutions of the instant invention are employed. Generally, the polymers are used at a level of .05 parts per million active polymer to 5 parts per million active parts polymer for each part per million of total hardness found in the water system. Preferably a ratio of active polymer to total hardness shoulcl range from .05:1 to 5:1, most preferably the polymer to total hardness ratio should range from .1:1 to .4:1. At the levels described above, the polymeric materials of the instant invention provide excellent scale dispersing, thus keeping heat transfer surfaces clean and efficient.
Example 1 A sodium vinylsulfonate/acrylic acid copolymer was prepared accord-ing to the following:
: To a suitable container equipped with a stirrer, thermomete-r and nitrogen sparge tube was charged 254.28 grams of an aqueous solution contain-ing 25 percent by weight sodium vinylsulfonate and 330 grams of deionized wa-ter. With stirring, the mixture was heated to 45 C. while continuing the nitrogen purge. Upon reaching 45 C., a catalyst solution consisting of 5.1 grams of potasium per sulphate in a total of 50 grams of deionized water and 15.34 grams of sodium metabisulfite in a total of 50 grams deionized water was added to the reaction system. After a period of five minutes, 141 grams of acrylic acid was slowly added over 60 minutes to the reaction pot. The temperature of the reaction was allowed to rise to 65 C. and was maintained at that level. After addition of the acrylic acid was completed, the temper-ature of the reaction was maintained at 65 C. for two additional hours be-- 20 fore cooling the material and collection. The resulting material was a slightly viscous aqueous solution containing approximately 24.2 percent by weight of the copolymer. The material had an intrinsic viscosity of 0.162.
Example 2 An equivalent polymerization to Example 1 was conducted substitut-ing an equivalent molar charge of methacrylic acid for the acrylic acid in Example 1. The resultant copolymer produced, contained 24.8 percent polymer solids and had an intrinsic viscosity of 0.193.
Example 3 The subject polymers of Example 1 and 2 were evaluated in dispers-ing calcium phosphate. Example 1 satisfactorily dispersed calcium phosphates \ ~
at an active polymer to total hardness ratio of .1. While .~ parts per mil-lion of the polymer of Example 2 was required for equivalent performance.
In further experiments, it was found that the polymer of Example 1 transport-ed 97.5 percent of the feed hardness. The polymer of Example 2 transported 68 percent of the feed hardness. At a comparable parts per million active polymer to parts per million hardness ratio (.l/l.0) the polymer of Example l out-performed the polymer of Example 2 at a level of from 97.5 percent to 20 percent, based on total transported feed water. Typical boiler water con-tains both calcium and magnesium ions.
The polymer of Example l was found to have transported l00 percent of the calcium ion analyzed and 9l.5 percent of the magnesium ion analyzed or a total hardness of 97.2 percent when used at an optimum level of .l parts per million polymer to l part per million hardness. The polymer of Example 2 transported 62 percent of the calcium ion analyzed and 80 percent of the mag-nesium ion analyzed for a total transported hardness of 68 percent based upon an optimum ratio of .4 parts per million polymer to l part per million hard-ness.
As evidenced by the above, the surprising activity of the acrylic acid containing polymer as compared to a methacrylic acid containing polymer prepared by the same technique is observed. Based upon the fact that acrylic acid and methacrylic acid are functionally similar monomers, the increased activity of the acrylic acid material is surprising.
Example 4 One hundred sixty-nine and a half grams of a 25 percent solution of sodium vinylsulfonate in water was added to a 500 ml. resin pot. A nitrogen atmosphere was maintained. Then, 42 grams of acrylic acid was added. After 30 minutes, 0.08 grams of sodium bisulfite and 0.4 grams of po~assium persul-fate were added. A small exotherm was observed. The mass thickened. Stir-ring continued overnight and the material was evaluated after diluting by ad-ding 125 grams of water.
3l3 Example 5 A method utiliæing photocells to determine the amount of turbidityin a given solution was developed. This system was utilized to determine the settling rate or stability of a calcium phosphate suspension. Since dis-persancy activity is defined as the ability of a molecule to minimize aggrega-tion of dispersant particles, the polymer of Example 4 was tested. 80 ml of a solution containing 1,000 ppm of trisodium phosphate was prepared and ad-Justed to a ph of between 11.7 and 12.0 with 1.0 N sodium hydroxide. The appropriate amount of polymer from Example 4 was also added to 80 ml of a second solution containing 750 ppm of calcium chloride. The solutions were mixed for approximately ten minutes after which time stirring was terminated and turbidity was monitored.
A change in turbidity of not more than 0.5 unit for a period of not less than 22 minut0s is indicative of a stable suspension. Unstable suspen-sions rapidly precipitate and a large decrease in turbidity is noted. Thefollowing table shows the use of the copolymer of Example 4 at 0.1 ppm treat-ment level to 1.0 ppm Ca2 as CaC03 and also at 0.5 ppm treatment to 1.0 ppm Ca2 as CaC03.
ppm co2polymer vs. Time Turbidity ppm Ca as CaC03 (Mins.) 0.1/1.0 ppm 0 23.8 " " 1 23.4 " " 2 22.0 " " 3 22.5 " " 6 12.0 9 7.0 " " 22 7.1 0.5/1.0 ppm 0 24.0 " " 3 24.1 ; TABLE I CONT'D
ppm co-polymer vs. Time Turbidity ppm Ca2+ as CaC03 (Mins.) 0.5/1.0 ppm 6 24.1 9 24.0 " " 12 24.1 " " 22 24.0 As the table demonstrates 0.5 ppm treatment to 1.0 ppm Ca2+ as CaC03 is stable and 0.1 ppm treatment to 1.0 ppm Ca2 as CaC03 is unstable.
Table II shows results using various materials and dosages to try to achieve a stable dispersion.
TABLE II
Intrinsic ppm trzeatment Material Viscosity ppm Ca as CaC03 vinylsulfonate/ 0.162 0.1/1.0 acrylic acid vinylsulfonate/
acrylic acid 2.45 0.4/1.0 sulfonate Mol. Wt. Failed to polystyrene 25,000 Disperse at
~inding utility in boiler water, cooling water, and other industrial process applications, the polymers have been employed to keep metallic surfaces in contact with process water substantially free of mineral scale in these and other industrial applications.
Examples of prior art water soluble polymer dlspersants include the use of a maleic anhydride-vinyl acetate copolymer. United States Patent No. 3,444,054 shows the utilization of polymethacrylic acid. United States Patent No. 3,682,22~ to sleyle shows the use of methacrylic acid-vinyl sulfonate copolymers to disperse scale in water handling systems. Other materials whlch have been used in application of these types include polyacrylic acid, sulfonated starch derivatives and various copolymers of acrylic acid with other comonomers including acrylamide, methacrylamide, methylacrylate, etc. These polymeric materials oveTall are used in the water system at levels so as to cause the complete dispersion of scale-forming constituents and thus render the heat transfer surfaces contacting the water more efficient.
This invention contemplates the use o~ specific copolymers of acrylic acid and/or its alkali metal or ammonium salts with an alkali metal vinylsulfonate. These materia~ when prepared in the manner described, give superior activity in reducing the scale on heat transfer surfaces. These polymers are believed to be unique in their high activity to dispersing inorganic scale forming constituents found in industrially used waters.
Thus this invention seeks to provide to the art an acrylic ; acid-alkali metal vinylsul~onate copolymer useful as an additive to prevent scale formation in industrial water systems.
This invention also seeks to provide ~ 1 _ ., . .
a copolymer of acrylic acid - sodium vinylsulfonate, the copolymer having a mole ratio of acrylic acid to sodium ~inylsulfonate of from 90:10 to 60:40, the polymer having a molecular weight in the range of 1,000 - 60,000.
Additionally, this invention seeks to provide a composition including an acrylic acid - sodium vinylsulfonate copolymer for use in industrial water systems and particular]y in industrial boiler water.
THE COh~OSITION
As detailed abo~e, the composition of this invention is a copolymer of acrylic acid and an alkali metal vinylsulfonate The term acrylic acid as used in this in~ention also includes the alkali metal salts of acrylic acid, such as the sodium and/or potassium forms, as well as the ammonium salt. The vinylsulfonate employed is generally utilized as an alkali metal salt from the group consisting of sodium and/or potassium. Due to cost considerations, the sodium salt form is preferred. Vinyl sulfonic acid may also be used.
The composition of this invention generally con~ains from lQ-90 mole percent o acrylic acid or its water soluble salts.
Perferably, the composition of the instant invention contains from 85-35 mole percent of acrylic acid or its water soluble salt and most preferably from 80-60 mole percent of acrylic acid or its water soluble salts.
Polymer of acry~lic aci`d and sodium vinylsulfonate can be prepared by ~ell known conventional solution polymerization techniques.
~enerally these materials are prepared from 10-50 and more preferably 15-35 percent aqueous polymer solutions. The molecular weight of the polymers useful in this invention may range from as low as 500 to as high as 150,000. Preferably the molecular weight range will ~ary from 75Q to approximately 50,000 and most preferably from 900 to 15,000.
" .
ldeally the polymer has a molecular weight o~ ~rom 1,000 to 6JOOO.
It is important in selecting the polymers for use in thls invention that they remain completely water soluble. The polymers of the instant invention may be pr0pared in a variety of ways.
~ethod o preparation is unimportant so long as a polymer satisfying the requirements stated above is obtained. The polymers accordingly may be produced in aqueous solution utilizing conventional red-ox catalysts, water soluble peroxicde catalysts or the like.
The polymers may be made by batch process or by adding the acrylic acid monomer in the presence of a catalyst to an aqueous soltuion of the vinylsulfonate monomer at a specified polymeriza~ion temperature.
As stated above, the copolymer o~ the instant invention find great utility as polymeric dispersants for inorganic scale forming constituents found in industrial water handling systems.
These systems, such as both once-through and re-circulating industrial : cooling water systems, boiler water systems and the like where water is concentrated to relatively high levels of dissolved solids, lend themselves to the applicability of the use of the polymers of the instant invention. The polymers of the instant invention have been found to be particularly useful in industrial boiler water as scale dispersants.
rn typical applications of the polymers of the instant inven-tion they are utilized at levels sufficient to disperse any suspended solids present in the water system. Generally, small amoun~ of the polymeric solutions of the instant invention are employed. Generally, the polymers are used at a level of .05 parts per million active polymer to 5 parts per million active parts polymer for each part per million of total hardness found in the water system. Preferably a ratio of active polymer to total hardness shoulcl range from .05:1 to 5:1, most preferably the polymer to total hardness ratio should range from .1:1 to .4:1. At the levels described above, the polymeric materials of the instant invention provide excellent scale dispersing, thus keeping heat transfer surfaces clean and efficient.
Example 1 A sodium vinylsulfonate/acrylic acid copolymer was prepared accord-ing to the following:
: To a suitable container equipped with a stirrer, thermomete-r and nitrogen sparge tube was charged 254.28 grams of an aqueous solution contain-ing 25 percent by weight sodium vinylsulfonate and 330 grams of deionized wa-ter. With stirring, the mixture was heated to 45 C. while continuing the nitrogen purge. Upon reaching 45 C., a catalyst solution consisting of 5.1 grams of potasium per sulphate in a total of 50 grams of deionized water and 15.34 grams of sodium metabisulfite in a total of 50 grams deionized water was added to the reaction system. After a period of five minutes, 141 grams of acrylic acid was slowly added over 60 minutes to the reaction pot. The temperature of the reaction was allowed to rise to 65 C. and was maintained at that level. After addition of the acrylic acid was completed, the temper-ature of the reaction was maintained at 65 C. for two additional hours be-- 20 fore cooling the material and collection. The resulting material was a slightly viscous aqueous solution containing approximately 24.2 percent by weight of the copolymer. The material had an intrinsic viscosity of 0.162.
Example 2 An equivalent polymerization to Example 1 was conducted substitut-ing an equivalent molar charge of methacrylic acid for the acrylic acid in Example 1. The resultant copolymer produced, contained 24.8 percent polymer solids and had an intrinsic viscosity of 0.193.
Example 3 The subject polymers of Example 1 and 2 were evaluated in dispers-ing calcium phosphate. Example 1 satisfactorily dispersed calcium phosphates \ ~
at an active polymer to total hardness ratio of .1. While .~ parts per mil-lion of the polymer of Example 2 was required for equivalent performance.
In further experiments, it was found that the polymer of Example 1 transport-ed 97.5 percent of the feed hardness. The polymer of Example 2 transported 68 percent of the feed hardness. At a comparable parts per million active polymer to parts per million hardness ratio (.l/l.0) the polymer of Example l out-performed the polymer of Example 2 at a level of from 97.5 percent to 20 percent, based on total transported feed water. Typical boiler water con-tains both calcium and magnesium ions.
The polymer of Example l was found to have transported l00 percent of the calcium ion analyzed and 9l.5 percent of the magnesium ion analyzed or a total hardness of 97.2 percent when used at an optimum level of .l parts per million polymer to l part per million hardness. The polymer of Example 2 transported 62 percent of the calcium ion analyzed and 80 percent of the mag-nesium ion analyzed for a total transported hardness of 68 percent based upon an optimum ratio of .4 parts per million polymer to l part per million hard-ness.
As evidenced by the above, the surprising activity of the acrylic acid containing polymer as compared to a methacrylic acid containing polymer prepared by the same technique is observed. Based upon the fact that acrylic acid and methacrylic acid are functionally similar monomers, the increased activity of the acrylic acid material is surprising.
Example 4 One hundred sixty-nine and a half grams of a 25 percent solution of sodium vinylsulfonate in water was added to a 500 ml. resin pot. A nitrogen atmosphere was maintained. Then, 42 grams of acrylic acid was added. After 30 minutes, 0.08 grams of sodium bisulfite and 0.4 grams of po~assium persul-fate were added. A small exotherm was observed. The mass thickened. Stir-ring continued overnight and the material was evaluated after diluting by ad-ding 125 grams of water.
3l3 Example 5 A method utiliæing photocells to determine the amount of turbidityin a given solution was developed. This system was utilized to determine the settling rate or stability of a calcium phosphate suspension. Since dis-persancy activity is defined as the ability of a molecule to minimize aggrega-tion of dispersant particles, the polymer of Example 4 was tested. 80 ml of a solution containing 1,000 ppm of trisodium phosphate was prepared and ad-Justed to a ph of between 11.7 and 12.0 with 1.0 N sodium hydroxide. The appropriate amount of polymer from Example 4 was also added to 80 ml of a second solution containing 750 ppm of calcium chloride. The solutions were mixed for approximately ten minutes after which time stirring was terminated and turbidity was monitored.
A change in turbidity of not more than 0.5 unit for a period of not less than 22 minut0s is indicative of a stable suspension. Unstable suspen-sions rapidly precipitate and a large decrease in turbidity is noted. Thefollowing table shows the use of the copolymer of Example 4 at 0.1 ppm treat-ment level to 1.0 ppm Ca2 as CaC03 and also at 0.5 ppm treatment to 1.0 ppm Ca2 as CaC03.
ppm co2polymer vs. Time Turbidity ppm Ca as CaC03 (Mins.) 0.1/1.0 ppm 0 23.8 " " 1 23.4 " " 2 22.0 " " 3 22.5 " " 6 12.0 9 7.0 " " 22 7.1 0.5/1.0 ppm 0 24.0 " " 3 24.1 ; TABLE I CONT'D
ppm co-polymer vs. Time Turbidity ppm Ca2+ as CaC03 (Mins.) 0.5/1.0 ppm 6 24.1 9 24.0 " " 12 24.1 " " 22 24.0 As the table demonstrates 0.5 ppm treatment to 1.0 ppm Ca2+ as CaC03 is stable and 0.1 ppm treatment to 1.0 ppm Ca2 as CaC03 is unstable.
Table II shows results using various materials and dosages to try to achieve a stable dispersion.
TABLE II
Intrinsic ppm trzeatment Material Viscosity ppm Ca as CaC03 vinylsulfonate/ 0.162 0.1/1.0 acrylic acid vinylsulfonate/
acrylic acid 2.45 0.4/1.0 sulfonate Mol. Wt. Failed to polystyrene 25,000 Disperse at
2.0/1.0 sulfonated poly- Mol. Wt. Failed to vinyl alcohol 6,600 disperse at 2.0/1.0 vinylsulfonate/ .193 .4/1.0 methacrylic acid (27:73 molar %) As shown the sulfonated polystyrene and the sulfonated polyvinyl alcohol failed to achieve stable dispersions even up to dosages up to 2.0 ppm treat-ment to 1.0 ppm Ca as CaC03.
`~ 10 As demonstrated by the results in the tables, the copolymers of acrylic acid and sodium vinylsulfonate are useful in dispersing solids in ` suspension and inhibiting the precipitation of scale forming solids in boiler systems.
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. . .
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`~ 10 As demonstrated by the results in the tables, the copolymers of acrylic acid and sodium vinylsulfonate are useful in dispersing solids in ` suspension and inhibiting the precipitation of scale forming solids in boiler systems.
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Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of dispersing and suspending finely divided inorganic particulate scale forming constituents in industrial water handling systems which comprises adding to the water from 0.05 to 5.0 ppm of a copolymer based on ppm hardness in the water system, said copolymer being a copolymer of acrylic acid or its alkali metal or ammonium salts and an alkali vinylsulfonate having a molecular weight of from 750 to 50,000,said copolymer containing from 10 to 90 mole percent of acrylic acid based units.
2. The method of Claim 1 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate has a molecular weight of 900 to 15,000.
3. The method of Claim 1 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate has a molecular weight of 1,000 to 6,000.
4. The method of Claim 1 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate contains from 60 to 80 mole percent of acrylic acid based units.
5. The method of Claim 1 wherein the industrial water handling system is a boiler water system.
6. The method of Claim 2 wherein the alkali metal vinylsulfonate is sodium vinylsulfonate.
7. The method of Claim 1 wherein .1 - .4 ppm of the copolymer is added based on ppm hardness in the water system.
8. A composition for treating industrial water systems which comprises an aqueous solution of a copolymer of acrylic acid, or the alkali metal or ammonium salts thereof and an alkali metal vinylsulfonate, the copolymer having a molecular weight of from 750 to 50,000, and containing from 10 to 90 mole percent of acrylic acid based units.
9. The composition of claim 8 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate has a molecular weight of 900 to 15,000.
10. The composition of claim 8 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate has a molecular weight of 1,000 to 6,000.
11. The composition of claim 8 wherein the copolymer of acrylic acid and alkali metal vinylsulfonate contains from 60 to 80 mole percent of acrylic acid based units.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15418680A | 1980-05-29 | 1980-05-29 | |
| US154,186 | 1980-05-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1148438A true CA1148438A (en) | 1983-06-21 |
Family
ID=22550355
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000377477A Expired CA1148438A (en) | 1980-05-29 | 1981-05-13 | Use of acrylic acid/sodium vinyl-sulfonate copolymers as dispersants in boiler applications |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1148438A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4898677A (en) * | 1986-11-10 | 1990-02-06 | National Starch And Chemical Corporation | Process for inhibiting scale formation and modifying the crystal structure of barium sulfate and other inorganic salts |
| US4937002A (en) * | 1989-06-12 | 1990-06-26 | National Starch And Chemical Investment Holding Corporation | Interpolymers for barium sulphate inhibition |
-
1981
- 1981-05-13 CA CA000377477A patent/CA1148438A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4898677A (en) * | 1986-11-10 | 1990-02-06 | National Starch And Chemical Corporation | Process for inhibiting scale formation and modifying the crystal structure of barium sulfate and other inorganic salts |
| US4937002A (en) * | 1989-06-12 | 1990-06-26 | National Starch And Chemical Investment Holding Corporation | Interpolymers for barium sulphate inhibition |
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