Method for modifying polysaccharide material by sequenced homogeneous chemical functionalisation

Patent metadata

Field	Value
Publication number	US-2023331873-A1
Application number	US-202318113772-A
Country	US
Kind code	A1
Filing date	Feb 24, 2023
Priority date	Dec 22, 2017
Publication date	Oct 19, 2023
Grant date	—

Abstract

The present invention concerns a method for modifying a polysaccharide material, preferably an amylaceous material, involving a first step of homogeneous solubilisation of said polysaccharide material in an aqueous solvent, followed by a step of homogeneous chemical functionalisation comprising at least one non-crosslinking chemical modification, or at least one crosslinking chemical modification, or a sequence of at least one non-crosslinking chemical modification and at least one crosslinking chemical modification. Secondly, the present invention concerns a modified polysaccharide material, in particular obtained by the method according to the invention, characterised in that it has a novel distribution of the chemical substituents attached to the hydroxyl functions of the anhydroglucose units of said polysaccharide material. The novel starches can be used as organic adjuvants for dry mortars made from cement or made from gypsum, in particular as a binder for a dry mortar made from cement or as a thickening agent for a mortar made from plaster.

First claim

1 - 15 . (canceled)

16 . A process for modifying a polysaccharide material including anhydroglucose units, comprising the dissolution, preferentially the total dissolution, of this polysaccharide material, and homogeneous chemical functionalization of the dissolved polysaccharide material, characterized in that:
a. the dissolution is performed before the chemical functionalization, b. the chemical functionalization consists of a sequence of at least two non-crosslinking esterifications chosen between hydroxyalkylation and carboxyalkylation.

17 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein a non-crosslinking esterification is a hydroxyalkylation, performed until the polysaccharide material has a degree of substitution of between 0.05 and 2.

18 . The process for modifying a polysaccharide material as claimed in claim 17 , wherein a non-crosslinking esterification is a hydroxyalkylation performed until the polysaccharide material has a degree of substitution of between 0.1 and 1, preferentially between 0.15 and 0.6.

19 . The modified polysaccharide material as claimed in claim 16 , wherein a non-crosslinking chemical esterification is a hydroxyalkylation and wherein the hydroxyalkyl group is chosen from hydroxypropyl or hydroxyethyl, preferentially hydroxypropyl.

20 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein the non-crosslinking esterification is a carboxyalkylation, performed until the polysaccharide material has a degree of substitution of between 0.03 and 2.

21 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein the non-crosslinking esterification is a carboxyalkylation, performed until the polysaccharide material has a degree of substitution of between 0.03 and 1, preferentially between 0.03 and 0.3.

22 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein a non-crosslinking chemical esterification is a carboxyalkylation and wherein the carboxyalkyl group is carboxymethyl.

23 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein the chemical functionalization consists of a sequence of at least two non-crosslinking esterifications wherein the hydroxyalkylation preceeds that carboxyalkylation.

24 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein a non-crosslinking chemical modification is a hydroxyalkylation, performed until the hydroxyalkyl groups substituting the hydroxyl functions of the anhydroglucose units of the polysaccharide material are distributed in the following manner:
at most 68%, preferentially at most 65%, very preferentially at most 64% in position 2, and/or at least 15%, preferentially at least 17%, very preferentially at least 17.5% in position 3, and/or at least 15%, preferentially at least 17%, very preferentially at least 18% in position 6,
the sum of the percentages of the hydroxyalkyl groups substituting the hydroxyl functions being equal to 100% and these percentages being measured by proton NMR.

25 . The process for modifying a polysaccharide material as claimed in claim 16 , wherein a non-crosslinking chemical modification is a carboxyalkylation, performed until the carboxyalkyl groups substituting the hydroxyl functions of the anhydroglucose units of the polysaccharide material are distributed in the following manner:
at least 75.5%, preferentially at least 76.5% in position 2, and/or at most 20%, preferentially at most 19% in position 3, and/or at least 4%, preferentially at least 5% in position 6,
the sum of the percentages of the carboxyalkyl groups substituting the hydroxyl functions being equal to 100% and these percentages being measured by proton NMR.

26 . A modified polysaccharide material including anhydroglucose units, preferentially a modified starch, which is totally water-soluble, the hydroxyl functions of said anhydroglucose units being substituted with at least one hydroxyalkyl chemical group and characterized in that the hydroxyalkyl groups substituting the hydroxyl functions are distributed in the following manner:
at most 68%, preferentially at most 65%, very preferentially at most 64% in position 2, and/or at least 15%, preferentially at least 17%, very preferentially at least 17.5% in position 3, and/or at least 15%, preferentially at least 17%, very preferentially at least 18% in position 6,
the sum of the percentages of the hydroxyalkyl groups substituting the hydroxyl functions being equal to 100% and these percentages being measured by proton NMR.

27 . The modified polysaccharide material as claimed in claim 26 , the hydroxyl functions of said anhydroglucose units being substituted with at least one carboxyalkyl chemical group and characterized in that the carboxyalkyl groups substituting the hydroxyl functions are distributed in the following manner:
at least 75.5%, preferentially at least 76.5% in position 2, and/or at most 20%, preferentially at most 19% in position 3, and/or at least 4%, preferentially at least 5% in position 6,
the sum of the percentages of the carboxyalkyl groups substituting the hydroxyl functions being equal to 100% and these percentages being measured by proton NMR.

28 . The modified polysaccharide material as claimed in claim 26 , characterized in that the hydroxyalkyl group is chosen from hydroxypropyl or hydroxyethyl, and is preferentially hydroxypropyl.

29 . The modified polysaccharide material as claimed in claim 26 , characterized in that the hydroxyalkyl group is a hydroxypropyl group, and characterized in that its degree of hydroxypropyl substitution is between 0.05 and 2, preferentially between 0.1 and 1 and most preferentially between 0.15 and 0.6.

30 . The modified polysaccharide material as claimed in claim 26 , characterized in that the carboxyalkyl group is carboxymethyl.

31 . The modified polysaccharide material as claimed in claim 26 , characterized in that its degree of carboxymethyl substitution is between 0.03 and 2, preferentially between 0.03 and 1 and most preferentially between 0.03 and 0.3.

32 . The modified polysaccharide material as claimed in claim 26 , characterized in that it is in the form of a powder which has a volume-mean diameter, measured by dry-route laser scattering, of between 10 μm and 1 mm, preferentially between 50 μm and 500 μm.

33 . The modified polysaccharide material as claimed in claim 26 , characterized in that it is soluble without heating, preferentially at least 95% amorphous, more preferentially at least 98% amorphous and most preferentially totally amorphous.

34 . A dry mortar composition, preferentially a dry mortar for tile adhesive, and most preferentially a mortar for ceramic tile adhesive, comprising an organic adjuvant comprising the modified polysaccharide material obtained according to the method of claim 16 .

35 . A gypsum-based mortar, preferentially in a spraying plaster or in a plasterboard plaster, comprising the modified polysaccharide material obtained according to the method of claim 16 .

Assignees

• Roquette Freres

Inventors

• Bock Solène
• Wiatz Vincent
• Guglielmetti Thomas
• Attard Joffrey

Classifications

• C08B31/12 Primary

  having alkyl or cycloalkyl radicals substituted by heteroatoms, {e.g. hydroxyalkyl or carboxyalkyl starch} · CPC title

• C04B24/38 Primary

  Polysaccharides or derivatives thereof {(C04B24/243 takes precedence)} · CPC title

• C04B28/04

  Portland cements · CPC title

• C04B28/14

  containing calcium sulfate cements {(gypsum-paper plates E04C)} · CPC title

• C08B31/006

  Crosslinking of derivatives of starch · CPC title