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Modified Cellulose Ether

Commercial-grade cellulose ethers cover a wide range of product types and differ in terms of substituents, substitution level, molecular weight (viscosity), and particle size. Predominant cellulose ether types are:

• Methyl cellulose (MC)
• Methylhydroxyethyl cellulose (MHEC or HEMC)
• Methylhydroxypropyl cellulose (MHPC or HPMC)

Also used:

• Hydroxyethyl cellulose (HEC) [20,37]
• Hydroxypropyl cellulose (HPC) [20,37]
• Ethyl-HEC (EHEC)
• Methyl-Ethyl-HEC (MEHEC) [118]
• Butylglycidylether-HEC [31,43,120]
• Laurylglycidylether-HEC [43,78]
• carboxymethylated MHEC or MHPC [34]
• Sodium carboxymethyl cellulose (Na-CMC) [2,13,14,22]

Those derivatives of HEC with alkyl side-chains containing more than two C-atoms are so-called hydrophob modified HEC (hmHEC or HMHEC).

A lot of those cellulose ethers used in building industry (generally knows as "modified cellulose ether") are blends with other additives. Their function may be to improve desired properties, to reduce or wholly suppress undesirable properties, or to add new properties:

• improve sag-resistance
• reduce stickiness
• increase water retention
• control air-content
• improve wetting and/or solubility in cold water
• add hydrophobicity
• control setting behaviour

The components may be physically blended or chemically bonded. Examples for both alternatives as well as for the intermediate are listed below:

Physically Blends

Die meisten Additive werden getrennt hergestellt und vermahlen und erst dann mit dem Celluloseether gemischt. Die wichtigsten Modifizierungsmittel für Celluloseether sind die Stärkeether und die Polyacrylamide.

• Polyacryl amides [2,13,22,30,31,35,41,123]
• Starch ethers [2,13,14,28,30,31,35,36,42,66,123]
• Quellstärke [3]
• Polyvinyl alcohols [4,13,22,36]
• Guar derivatives (guar ether, quaternary substituted guar) [10,41,42]
• Phyllosilicates, layered silicates, especially smectite clays (hectorite, montmorillonite, bentonite), china-clay, talc [13,14,22,70,104]
• fibrous silicates (sepiolithe, attapulgite, wollastonite) [10,13,14,22,28,103]
• Lignin sulfonate [2,37]
• Melaminsulfonate formaldehyd-condensation product [2,37,42]
• Naphthalinsulfonate formaldehyd-condensation product [2,37,42]
• Polycarboxylate [37,68]
• Surfactants like sodium lauryl sulfate [2] or alpha-olefinesulfonate
• Metalsoaps and other hydrophobizing agents [11,16,38]
• Polyethylene oxide [13,22]
• Glycoles and their derivatives [6,11,39]
• Defoamers [4,48,68]
• Superabsorbents (water-insoluble, but water-swellable polymers) [5,12,35,40,42,123]
• Sodium gluconate [15]
• Xanthan Gum [14,41,42]
• Borax, boric acid [49]
• Redispersionpowders [36]

In principle modified cellulose ethers may contain each thinkable mortar additive, but in practice they are limited to those, whose action is almost independent of the binder system. Set retarder and accelerators are an example for less suitable candidates for blending because of their individual interaction with different binders.

Chemically bonded components

The additive may be linked to the cellulose ether molecule, for example:

• Cellulose ether-polyacryl amid adducts [8]
• Cellulose ether adducts with terpolymers of AMPS, acrylamide, and ethylacrylate [29]

In-between case (no pure physically blend and not chemically bonded)

This group includes coated cellulose ethers and solid solutions:

• Cellulose ether treated with paraffins [32,38]
• Cellulose ether treated with calcium stearate [38]
• Cellulose ether treated with dimethylsiloxanes [38]
• Cellulose ether treated with polymers based on acrylic acid, maleic acid, and other carboxylic groups containing monomers [41]
• Mixed phase (solid solution) of cellulose ether and polyvinyl alcohol [7]
• Mixed phase (solid solution) of cellulose ether and surfactant [45]

Additives without action in the mortar

Some additives shall not influence any properties of the mortar. The reason for their use is to improve properties like shelf-live, handling and/or transportability:

• Paraffins or mineral oils (prevent separation of the components) [27]
• Polyethylen glycols and EO/PO copolymers (prevent separation of the components) [27]
• Preservatives [27]
• Anticake (china-clay, aluminium silicates, wood flour, cellulose powder, precipitated silica, silica fume) [27]

References

[2]   DE 3920025-A1

Bietz R, Grünberger E, Kunz U, Ziche H. Aqualon GmbH. Additive mixts. for gypsum materials - contain cellulose derivs., thickeners and fluidiser(s).
 

[3]   US 5575840

DeWacker DR. National Starch and Chemical Investment Holding Corporation. Cement mortar systems using blends of polysaccharides and cold-water-soluble, unmodified starches.
 

[4]   US 4118241

Bernett FE. Tile Council of America Inc. Mortar compositions and method of making same.
 

[6]   US 4211572

Wagner HB, Ellis JR. Tile Council of America Inc. Dry-set mortars and method for improving the water retentivity thereof. Equivalent: DE 2900327.
 

[7]   US 2002/0045684-A1

Bacher A, Bauer W, Dietrich U et al. Wacker Chemie GmbH. Thickener compositions containing vinyl alcohol copolymers and cellulose ethers. Equivalent: DE 10040172-A1.
 

[8]   US 4330441

Böhmer B, Hoppe L, Szablikowski K, Kudora D, Behn R. Wolff Walsrode AG. Solvent-soluble substances characterized in that water-soluble cellulose ethers are chemically bonded to water-soluble, at least predominatel. Equivalents: EP 0014258, DE 2900110.
 

[10]   EP 1090889-A1

Alvarez Berenguer A, Limpo Orozco FJ, Del Valle Alvarez BE, Hidalgo MM. Tolsa SA. Additive for special plasters and mortars, compositions containing the additive and utilization of the additive in special plasters and mortars. Equivalent: WO 9959933.
 

[11]   EP 0453921-A1

Weigand WA. WR Grace & Co. Non-emulsion masonry cement additives and method of producing masonry cement compositions containing same. Equivalent: US 5108511.
 

[13]   US 4021257

Bernett FE. Tile Council of America Inc. Cementious composition for use in preparing pointing compounds or mortar compounds.
 

[14]   EP 0773198-B1

Mann HJ. Clariant GmbH. Verdickersystem für Baustoffgemische. Equivalent: DE 1954194.
 

[15]   EP 1288175-A2

Wihler HD, Umlauf R, Mitkova D. Dyckerhoff AG. Schnellzement-Bindemittelmischung. Equivalent: DE10141864.
 

[16]   US 6547874-B2

Eck H, Adler K. Wacker Polymer Systems GmbH & Co KG. Hydrophobierungsmittel zur Hydrophobierung von gipsgebundenen Baustoffen, Verfahren zu dessen Herstellung sowie dessen Verwendung. Equivalents: EP 1120384, DE 10003495.
 

[20]   US 3824107

Weiant DS. AA Quality Constr Material Inc. Mortar compositions containing mixtures of hydroxyalkyl celluloses.
 

[22]   US 4043827

Bernett FE. Tile Council of America Inc. Sag-resistant dry-set mortar composition.
 

[27]   DE 2910374-A1

Knittel V, Stemmler H. Hoechst AG. Fließfähiges Gemisch auf der Basis eines hydrophilen Polymeren, ein Verfahren zu seiner Herstellung und seine Verwendung.
 

[28]   DE 3243573-A1

Rigips GmbH. Wasserhaltige Putzmischung auf Gipsbasis und weiteren Zuschlagstoffen.
 

[29]   US 4588772

Böhmer B, Lange W, Höhl, F. Wolff Walsrode AG. Water-soluble, polymer-modified hydroxyalkyl methyl cellulose and its use as an additive for asbestos-free tile adhesive formulations. Equivalents: DE 3339860, EP 0141360.
 

[30]   US 4654085

Schinski E. Henkel KGaA. Additive for cementitious compositions.
 

[31]   DE 3913518-A1

Schinski E, Wunderlich M. Aqualon GmbH. Additive mixt. for improved cement mortars for ceramic facings - comprises starch ether, polyacrylamide and water-soluble cellulose ether with hydroxyethyl and 3-alkoxy-2-hydroxypropyl residues.
 

[32]   DE 3910742-A1

Schweizer D, Schinski E. Aqualon GmbH. Verwendung von hydrophobierten, nicht-ionogenen Celluloseethern in Dispersionsfarben und so erhaltene Dispersionsfarben.
 

[34]   US 5372642

Bartz U, Dönges R, Klehr H. Hoechst AG. Use of carboxymethylated methyl hydroxyethyl cellulose ethers or methyl hydroxypropyl cellulose ethers. Equivalent: EP 0573847.
 

[35]   US 5387626

Böhme-Kovac J, Girg F, Mann HJ. Hoechst AG. Additive combination for improving the processing properties of water-containing mixtures of building materials. Equivalent: EP 0530768.
 

[36]   DE 4331141-A1

Hilscher G, Rennen H. Rigips GmbH. Joint filler.
 

[37]   US 5424099

Stewart GD, Carkner PM. WR Grace & Co. High strength pourable gypsum floor underlayments and methods of providing same.
 

[38]   US 5749964

Mann HJ. Hoechst AG. Building material mixture. Equivalents: DE 19543933, EP 0775678.
 

[39]   US 5679150

Kerkar AV, Dallaire MP. Drying shrinkage cement admixture. Equivalent: WO 9806678.
 

[41]   WO 9964368

Jeszenszky T, Dahms H, Eiffler J, Goerlach-Doht YM. The Dow Chemical Company. Additive composition for water-based building material mixtures.
 

[42]   US 5432215

Girg F, Böhme-Kovac J. Hoechst AG. Building material products containing organic polymers as thickeners. Equivalent: EP 0504870.
 

[43]   US 6068696

Anttila AL, Chu SG, Podlas TJ, Young TS. Hercules Inc. Flexural bond strength/low air/workability additive for mortar cement. Equivalents: EP 1098861, DE 69903173.
 

[45]   DE 10018155-A1

Hemmes A, Dönges R. Clariant GmbH. Verfahren zur Herstellung von gut benetzbaren, wasserlöslichen, pulverförmigen, mindestens alkylierten, nicht-ionischen Celluloseethern.
 

[48]   DE 10132745-A1

Bonder W. MIG Material Innovative Gesellschaft mbH. Entlüfter für hydraulisch abbindende Massen. Equivalent: WO 02090285.
 

[49]   US 5234968

Debus G, Lüdke M, Mann HJ. Hoechst AG. Thickening system for water-based building material mixes. Equivalents: DE 4016979, EP 0458328.
 

[66]   EP 0117431-A2

Gardenier KJ, Grünberger E, Ziche H. Henkel KGaA. Gipsmischungen mit einem Gehalt an Stärkeethern. Equivalent: DE 3302988.
 

[68]   US 6545067-B1

Büchner KH, Ehle M, Perner J, Oppenländer K, Hartmann M, Günther W, Kroner M. BASF AG. Additives for mineral building materials containing cement. Equivalents: DE 19842859, EP 1131269.
 

[70]   US 4447267

Chesney JJ jr, Broney SC. Tile Council of America Inc. Dry set grout.
 

[78]   EP 0314118-A2

McLachlan WC, Lukach C, Kirkland WJ. Aqualon Company. Cementing composition comprising water-soluble, nonionic hydrophobically modified hydroxyethyl cellulose and its use. Equivalent: US 4784693.
 

[103]   EP 1095913-B1

Alvarez Berenguer A. Tolsa SA. Technological additive for agglomerating projectable building materials and utilization of the additive in projected mortars and concretes.
 

[104]   EP 0675089-B1

Coutelle H, Dziwok K. Süd Chemie AG. Hilfsmittel für mineralische Bindemittelsysteme. Equivalent: DE 4410728.
 

[118]   WO 03048070-A1

Rydgren H, Stridh K. Akzo Nobel NV. Aqueous cement composition.
 

[120]   US 4939192

t'Sas HE. Aqualon Company. Building composition containing 3-alkoxy-2-hydroxypropylhydroxyethyl cellulose.
 

[123]   EP 0530768-B1

Böhme-Kovac J, Girg F, Mann HJ. Hoechst AG. Zusatzmittelkombination zur Verbesserung der Verarbeitbarkeit von wasserhaltigen Baustoffgemischen. Equivalent: US 5387626.