Back to results
US 2017/0362360 A1Published application
Method for the preparation of copolymers of alkyl methacrylates and maleic anhydride
AssigneeEvonik Oil Additives GmbH
InventorsRhishikesh GOKHALE, Sandra MUEHLING, Miriam Kathrin STIHULKA, Klaus SCHIMOSSEK, Frank-Olaf MAEHLING
Life of this patent
Estimating the term…
Abstract
A method for the preparation of a copolymer containing at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 4000 to 18000 g/mol proceeds by solution polymerization in the presence of a radical initiator.
Claims11
1:
- A method for the preparation of a sulfur-free copolymer comprising alkyl methacrylate monomer units and maleic anhydride monomer units by solution polymerization of one or more alkyl methacrylates and maleic anhydride in a solvent in the presence of a radical initiator, said method comprising:
- a) providing an initial reaction solution comprising maleic anhydride, a portion of the radical initiator and solvent, and
- b) adding a feed solution comprising one or more alkyl methacrylates and a portion of the radical initiator to the initial reaction solution.
2:
- The method according to claim 1, wherein the feed solution is added over the course of 30 minutes to 12 hours.
3:
- The method according to claim 1, wherein the initial reaction solution comprises 50 to 100 wt-% maleic anhydride based on the total amount of maleic anhydride.
4:
- The method according to claim 1, wherein the molar ratio of the one or more alkyl methacrylates to the maleic anhydride is in the range of 10:1 to 1:1.
5:
- The method according to claim 1, wherein the initial reaction solution does not comprise any alkyl methacrylate.
6:
- The method according to claim 1, wherein the portion of the one or more alkyl methacrylates in the feed solution is 50 to 100 wt-% based on the total amount of the one or more alkyl methacrylates.
7:
- The method according to claim 1, wherein the total amount of the one or more alkyl methacrylates and the maleic anhydride is in the range of 10 to 80 wt.-% relative to the total weight of the sum of the initial reaction solution and the feed solution.
8:
- The method according to claim 1, wherein at least 80 mol-% of the one or more alkyl methacrylates are selected from the group of C6 to C22 alkyl methacrylates, or a mixture thereof.
9:
- The method according to claim 1, wherein a portion or all of the solvent is selected from the group consisting of methyl ethyl ketone, isobutyl methyl ketone, anisole, n-butanol, dimethylformamide, dimethyl sulfoxide, benzene (petroleum ether), acetone, 1-hexene, ethanol, ortho-xylene, and mixtures thereof.
10:
- A sulfur-free copolymer obtained by the method as defined in claim 1, wherein the number average molecular weight of the copolymer is in the range of 4000 to 18000 g/mol and the polydispersity index of the copolymer is in the range of 1 to 5, wherein the number average molecular weight and the polydispersity index are determined by gel permeation chromatography against poly(methyl methacrylate) standards, and the molar ratio of the one or more alkyl methacrylates to the maleic anhydride in the resulting copolymer is in the range of from 10:1 to 1:1, based on the total molar amounts of the one or more alkyl methacrylates and maleic anhydride used for the preparation of the sulfur-free copolymer.
11:
- The sulfur-free copolymer according to claim 10, wherein the sulfur-free copolymer comprises equimolar amounts of the one or more alkyl methacrylates and maleic anhydride.