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1. WO2020157630 - POLY(ACIDE MÉTHACRYLIQUE) DE POIDS MOLÉCULAIRE ÉLEVÉ

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

What is claimed is:

1 . A process for producing a poly(methacrylic acid) having a weight average molecular weight of at least 200,000 Daltons, comprising the steps of:

(1) obtaining a water-based polymerization composition which comprises

(a) methacrylic acid in an amount of from about 1 % to about 20% by weight relative to the water-based polymerizable composition,

(b) at least one azo-containing radical initiator which has a water solubility of at least 0.05 gram per 100 g of water at 25±3°C and a 10-hour half life temperature of from about 40°C to about 90°C,

(c) a thiol-containing compound as a chain-transferring agent, and

(d) water,

wherein the water-based polymerizable composition has a pH of from about 3.0 to about 4.5,

wherein the mole ratio of component (a) to component (b) is at least about 800 while the molar ratio of component (b) to component (c) is from about 1 to about 3.0; and

(2) thermally polymerizing methacrylic acid in the water-based polymerizable

composition at a temperature of from about 40°C to about 90°C to obtain the poly(methacrylic acid).

2. The process of claim 1 , wherein the methacrylic acid is present in the water-based polymerizable composition in an amount of from about 1 .5% to about 15% (preferably from about 2% to about 10%, more preferably from about 3% to about 8%) by weight relative to the water-based polymerizable composition.

3. The process of claim 1 or 2, wherein said at least one azo-containing radical initiator has a 10-hour half-life temperature of from about 40°C to about 80°C.

4. The process of claim 1 or 2, wherein said at least one azo-containing radical initiator has a 10-hour half-life temperature of from about 40°C to about 70°C.

5. The process of claim 1 or 2, wherein said at least one azo-containing radical initiator has a 10-hour half-life temperature of from about 40°C to about 65°C.

6. The process of any one of claims 1 to 5, wherein the water-based polymerizable

composition has a pH of from about 3.0 to about 4.2.

7. The process of any one of claims 1 to 5, wherein the water-based polymerizable

composition has a pH of from about 3.0 to about 3.7.

8. The process of any one of claims 1 to 7, wherein the mole ratio of component (a) to component (b) is at least 2000.

9. The process of any one of claims 1 to 7, wherein the mole ratio of component (a) to component (b) is at least 2500 (preferably at least 3000).

10. The process of any one of claims 1 to 9, wherein the molar ratio of component (b) to component (c) is from about 1 .05 to about 2.5.

1 1 . The process of any one of claims 1 to 9, wherein the molar ratio of component (b) to component (c) is from about 1 .1 to about 2.0, preferably from about 1 .15 to about 1 .5.

12. The process of any one of claims 1 to 1 1 , wherein the step of thermally polymerizing is carried out at a temperature of from about 40°C to about 80°C (preferably from about 40°C to about 70°C, more preferably from about 40°C to about 65°C).

13. The process of any one of claims 1 to 12, wherein the thio-containing compound is selected from the group consisting of 2-mercaptoethylamine, 2-mercaptopropylamine, 3-mercaptopropylamine, 2-mercaptobutylamine, 3-mercaptobutylamine, 4- mercaptobutylamine, 1 -amino-2-methyl-2-propanethiol hydrochloride, N- methylaminoethanethiol, N-ethylaminoethanethiol, N-methylaminopropanethiol, N- ethylaminopropanethiol, N-methylaminobutanethiol, N-ethylaminobutanethiol, 2- (butylamino)ethanethiol, thioglycolic acid, ammonium thioglycolate, thiolactic acid, mercaptosuccinic acid, 2-mercaptoisobutyric acid, 2-methyl-3-sulfanylpropanoic acid, 4- mercaptobutyric acid, 6-mercaptohexanoic acid, 2-mercaptoethanol, 1 -mercapto-2- propanol, 1 -thioglycerol, 3-mercapto-1 -propanol, 4-mercapto-1 -butanol, 3-mercapto-1 - hexanol, 4-mercapto-4-methylpentan-2-ol, cysteine; 4-amino-5-mercapto-pentanoic acid, 3-mercapto-2-(methylamino)propanoic acid, and combinations thereof.

14. The process of any one of claims 1 to 12, wherein the thio-containing compound is 2- mercaptoethylamine.

15. The process of any one of claims 1 to 14, wherein the pH is achieved by adding a base selected from the group consisting of NaOH, NH4OH, KOH, and combinations thereof.

16. The process of any one of claims 1 to 15, wherein the pH is achieved by adding KOH.

17. A poly(methacrylic acid) obtained according to a process of any one of claims 1 to 16.

18. A poly(methacrylic acid), having: a weight average molecular weight of at least 400,000 Daltons (preferably at least 600,00 Daltons, more preferably at least 800,000 Daltons, even more preferalby at least 1 ,000,000 Daltons), a polydispersity index (PDI) of from about 2.0 to about 3.0 (preferably from about 2.0 to about 2.8, more preferably from about 2.0 to about 2.6), and a substituted-alkylthio group of -S-R at an end terminal, wherein R is a linear or branched C2-Ci0-alkyl group including one or two functional groups selected from the group consisting of -OH, -COOH, -NH2, -NHCH3, -NHC2H5, and combinations thereof.