Cellulose ethers are water-soluble polymers derived from cellulose,the most abundant polymer in nature. For more than 60 years,these versatile products have played an important role in a host of applications, from construction products, ceramics and paints to foods, cosmetics and pharmaceuticals.
For construction products, cellulose ethers act as thickeners, binders,film formers and water-retention agents. They also function as suspension aids, surfactants, lubricants, protective colloids and emulsifers. In addition, aqueous solutions of certain cellulose ethers thermally gel, a unique property that plays a key role in a surprising
variety of applications. This valuable combination of properties is not found in any other water-soluble polymer.
The fact that so many useful properties are simultaneously present and often act in combination can be a signifcant economic advantage. In many applications, two, three or more ingredients would be required to do the same job performed by a single cellulose ether product. In addition, cellulose ethers are highly effcient, often
yielding optimal performance at a lower concentration than that required with other water-soluble polymers.
Dow Construction Chemicals offers a wide array of cellulosic products, including methyl cellulose, hydroxyethyl cellulose and carboxymethyl cellulose. Methyl cellulose ethers are most widely used for many applications in the building and construction industry.
Chemistry of Cellulose Ethers
Our business offers cellulose ethers in four basic types:
1.Hydroxyethyl methyl cellulose (HEMC/MHEC)
2.Hydroxypropyl methyl cellulose (HPMC,MC)
3.Hydroxyethyl cellulose (HEC)
4.Carboxy methyl cellulose(CMC)
Both types have the polymeric backbone of cellulose, a natural carbohydrate that contains a basic repeating structure of anhydroglucose units . During the manufacture of cellulose ethers, cellulose fibers are heated with a caustic solution that, in turn, is treated with methyl chloride, and either propylene oxide or ethylene oxide, yielding hydroxypropyl methyl cellulose or hydroxyethyl methyl cellulose, respectively. The fibrous reaction product is purified and ground to a fine, uniform powder.
Special-grade products have also been formulated to meet the requirements of specifc industries.
Our cellulose ether products are available in three different forms: powder, surface-treated powder and granular. The type of product being formulated influences which form to select. In most dry-mix applications, untreated powder is typically used, whereas for ready-mix applications, in which the cellulosic powder is added directly to water, surface-treated powder or granular forms are preferred.
General Properties
General properties common to our cellulose ethers are listed here. Individual products exhibit these properties to varying degrees and may have
additional properties desirable for specific applications. For more information, email at sales@kimachemical.com .
|
Property |
Details |
Advantages |
|
Binding |
Used as high-performance binders for extruded fber-cement materials |
Green strength |
|
Emulsifcation |
Stabilize emulsions by reducing surface and interfacial tensions and by |
Stability |
|
Film formation |
Form clear, tough, flexible water-soluble flms |
• Excellent barriers to oils and greases |
|
Lubrication |
Reduces friction in cement extrusion; improves hand-tool workability |
• Improved pumpability of concrete, machine grouts and spray |
|
Nonionic |
Products have no ionic charge |
• Will not complex with metallic salts or other ionic species to form |
|
Solubility (organic) |
Soluble in binary organic and organic solvent/water systems for select types and grades |
Unique combination of organic solubility and water solubility |
|
Solubility (water) |
• Surface-treated/granular products can be added directly to aqueous |
• Ease of dispersion and dissolution |
|
pH stability |
Stable over a pH range of 2.0 to 13.0 |
• Viscosity stability |
|
Surface activity |
• Act as surfactants in aqueous solution |
• Emulsifcation |
|
Suspension |
Controls settling of solid particles in aqueous systems |
• Anti-settling of aggregate or pigments |
|
Thermal gelation |
Occurs to aqueous solutions of methyl cellulose ethers when heated above a particular temperature |
• Controllable quick-set properties Gels go back into solution upon cooling |
|
Thickening |
Wide range of molecular weights for thickening water-based systems |
• Range of rheological profles |
|
Water retention |
Powerful water-retention agent; keeps water in formulated systems |
• Highly effcient |
Cement-Based Tile Adhesives
Our products enable performance of thin-set mortars via water retention and with pseudoplastic rheological performance. Achieve creamy and easy workability and consistency, high water retention, improved wetting to the tile, excellent open time and adjustment time, and more.
Tile Grouts
Cellulose ethers function as a water retention and suspension aid. Discover easy workability, good adhesion to the edges of the tiles, low shrinkage, high abrasion resistance, good toughness and cohesion, and more.
Self-Leveling Underlayments
Cellulosics impart water retention and lubricity to improve flow and pumpability, minimize segregation and more.
Mortars for EIFS/Skim Coat
Deliver the perfect fnishing touch with improved workability, air void stabilization, adhesion, water retention and more.
Cement-Based Plasters
Deliver better performance through improved sag resistance, workability, open time, air-void stabilization, adhesion, water retention, yield and more.
Gypsum-Based Building Materials
Deliver the desired end result of a smooth, even and durable surface with consistent product quality and important performance features.
Cement and Cement-Fiber Extruded Materials
Reduce friction and impart lubricity to aid in extrusion and other forming processes.
Latex-Based Systems (Ready-to-Use)
A range of viscosity grades delivers good workability, delayed solubility, open time, adjustment time and more.
Post time: Nov-13-2018