Ethylcellulose

• E 462
• Cellulose ethyl ether

White to yellowish white, odorless or nearly odorless powder

Fixed

Ethylcellulose ( technical terminology, standard language: ethyl cellulose ) is a chemical compound that is obtained semi-synthetically from the naturally occurring cellulose. Chemically, it is a cellulose ether which occurs in various types, which differ mainly in the degree of polymerization ( thus in the molecular weight distribution and ). Ethylcellulose is like carboxymethyl cellulose or methyl cellulose is used; it is a hydrophilic white powder and is soluble in cold (but not hot) water and to form a viscous solution or a gel.

Production and representation

Ethyl cellulose is not found in nature but is produced synthetically by cellulose are in a hot alkaline solution ( an alkali, for example sodium hydroxide ) and then with ethyl halides - such as ethyl chloride - treated.

Chemical Properties

Chemically, ethyl cellulose, an ethyl ether of cellulose, and is formed by replacing hydrogen atoms of the hydroxy groups by ethyl groups.

Depending on the number of substituted hydroxyl groups is the ethyl celluloses differ. Cellulose is a chain molecule consisting of many glucose molecules, each glucose unit has three hydroxyl groups. Various ethylcelluloses can be described by their degree of substitution (degree of substitution, DS), describe the average number of etherified hydroxyl groups per glucose unit. The theoretical maximum of 3.0, typical values ​​are in the range of 2.2 to 2.6. Since the DS value of ethylcellulose is never uniform, there are always particles which can not be solved. Therefore, mixtures of cellulose ethers are often produced, which contain, in addition ethylcelluloses and hydroxypropylmethylcellulose (HPMC) and hydroxyethyl methylcellulose ( HEMC ), or methyl cellulose.

Due to the different functional groups -OH and- OC2H5 Ethycellulose has both hydrophilic and hydrophobic properties. Thereby reducing the surface tension in solution and has an emulsifying effect in two-phase mixtures. In concrete mixtures it increases the water holding capacity, thereby delaying the setting time, so have the concrete constituents more time for chemical reactions with the contained water. In ether blends, a film can be regulated by the addition of formaldehyde is formed.

Use

Ethyl cellulose is the main component of lightfast Celluloseetherlacken, packaging materials, thermoplastics, artificial snow for Christmas trees, cable insulation, protective skins and seals. Ethyl cellulose is used as an additive of synthetic resins and waxes for coating dyed Easter eggs and as an additive for stamp colors in the food industry ( stamping of eggs or cheese). She is a versatile compound that is used as thickeners, binders, adhesives, dispersing, suspending, emulsifying, sedimentation, filter aids, flocculants, source, lubricants and water-retaining agent and as a protective colloid and film formers.

Food and Beverage

Ethylcelluloses ( additive E number 462) as well as other chemically modified derivatives of cellulose (E 461 and 463-469 ) are approved in the EU as a food additive for various uses.

Pharmacy

Ethylcellulose is often used as a pharmaceutical excipient in the pharmaceutical preparation: for example, for increasing the viscosity in liquid pharmaceutical preparations, for the stabilization of emulsions and suspensions, as a gelling agent in creams and gels, as a binder for tablets granules, as a builder and disintegrant for tablets and in particular also as a film former for coating tablets.

Pharmaceutical grades of ethylcellulose included according to the characterization in the European Pharmacopoeia one Ethoxygruppenanteil from 44.0 % to 51.0 %.