ETHYL CELLULOSE

Ethyl Cellulose polymers are derived from cellulose. They inert, high purity powders with no caloric value and are virtually colorless, odorless and tasteless.

According to the DOW films made from ETHOCEL (a brand name of Ethyl cellulose) polymers are highly flexible and retain their flexible and retain their flexibility at temperatures well below freezing.

It is excellent as a film former. Films made from it are tough, with high tensile strength and unusual degree of flexibility even at low temperatures. It yields a greater volume of film-forming solids than any other cellulose derivative. It is compatible with most common plasticizers and polymers. It yields clear films with a wider variety of plasticizers and polymers and cellulose derivatives. It is also an excellent water barrier.

In films it absorbs a little moisture either on exposure to the atmosphere or after long immersion in water. The good binding qualities of it are useful in applications such as tableting and microencapsulation. Its solubility dissolves in a wide range of solvents such as aliphatic alcohols, chlorinated solvents, and natural oils. It is practically insoluble in glycerin, propylene glycol, and water.

In formulating with it other polymers are used to improve gloss, rubbing properties, adhesion, and resistance to certain solvents. Generally, the percentage of modifying polymer is approximately equal to that of the ETHOXYL polymer, and the amount of plasticizer will be about one-half that of the polymer total. However, depending on the application, the ratio of its polymer, plasticizer and modifying polymer can be varied greatly. Its products are compatible in all proportions with the following modifying polymers: Most pure phenolics, Modified phenolics, Coumarone indenes, Natural polymers processed natural polymers, Rosin, Rosin derivatives, and long oil alkyds.

It is incompatible with most of the short oil alkyds and vinyl chloride-type polymers. The film properties of this products yield a greater volume of film-forming solids per unit weight that can do most other commercial cellulose derivatives. Its films are completely transparent, colorless, flexible, and tough.
The tensile strength and elongation properties of films of ETHOCEL polymers bear a relationship to the intrinsic viscosity of the ETHOCEL product used in making the films.
I
n film form, ethylcellulose is well suited in properties and appearance as a wrapping material and as electrical insulation. Unplasticized film can be produced to have a high degree of toughness and flexibility. Unplasticized film 0.001 in thick, for example, can be flexed over 2,000 times on the MIT fold tester before failures occurs. Even at -70 degree Celsius the film has a high degree of flexibility. Tensile strength is on the order of 7,000 to 11,000 lbs/inch squared, while elongation runs 10 to approximately 25%, but has no appreciable effect on the dimensional stability on the film. In fact, ethyl cellulose film is not noticeably affected even after long immersion in water followed by drying.

The products yield a greater volume of film-forming solids per unit weight than do most other commercial cellulose derivatives. The tensile strength and elongation properties of films of the polymers bear a relationship to the intrinsic viscosity of the product used in making the films. Medium ethoxyl ETHOCEL products possess greater hardness and toughness than do Standard ethoxyl ETHOCEL products of similar viscosity. Hardness is measured by resistance to deformation. An understanding of the differences between Medium and Standard ETHOCEL products is helpful in formulating coatings for maximum flexibility and toughness. At a comparable molecular weight (viscosity), the Medium ethoxyl ETHOCEL product is “tougher” than the Standard ethoxyl ETHOCEL product. When mixtures of alcohols with aromatic hydrocarbons are used as solvents for ETHOCEL polymers without large proportions of plasticizers or other polymers, the mechanical properties of the deposited film are affected by last solvent to evaporate.

The single-dose oral toxicity of it is low. Based on an examination of the ingredients and their sources, this product is free of known allergy-stimulating food substances. So, ethyl cellulose polymers were not irritating to humans when applied in a 48 hour closed patch test and did not produce skin sensitization in human subjects. The absorption through the skin in acutely toxic amounts is low. Also, the U.S FDA recognized the ethyl cellulose as a “generally as safe”. The dust of it may cause a temporary mechanical eye irritation to the eye under extreme conditions. They are considered as nuisance dusts when inhale. As a result, the products are considered to present no significant health hazard, no special precautions need be observed to handle the product.

Dusts of ethyl cellulose polymers in air can reach explosive levels, and care must be taken to prevent this. It is an organic material that will burn under the right conditions of heat and oxygen supply. These polymers will melt upon exposure to an open flame. Burning behavior and explosiveness get worse as moisture content decrease.