DINP is a mixture of isomers that have alkyl chains from 7 to 9 carbons long, but the largest portion of the mixture have chains composed of 8-carbon in length (a.k.a. isononyl alcohol).
DINP is a general purpose plasticizer with a broad range of applications used in flexible PVC. It is widely used in the toy, construction, and general consumer product markets. It has limited use in food packaging and is not used in medical applications.
Plasticizers are polymer additives that serve to increase the polymer’s flexibility, elongation and ease of processing. In other words, they make the polymer more workable. In technical terms, the addition of a plasticizer generally causes a reduction in the cohesive intermolecular forces along polymer chains. The chains can then move more freely relative to one another, hence reducing the stiffness of the polymer.
The use of plasticizers began in the mid 1860s when castor oil was added to Cellulose Nitrate. The most commonly measured physical effects include melt viscosity, elasticity modulus, and the glass transition temperature. Other types of plasticizers have been used through the years, but in the late 1930s, phthalates were introduced because they were believed to be less toxic. The two most common plasticizers used today are di-2-ethylhexyl phthalate (DEHP) and di-isononyl phthalate (DINP), both of which are generally used in the manufacture of PVC related products.
The Phthalate Plasticizer Market
In 1999, the global volume of plasticizers was approximately 10 billion lbs., or about $5 billion, The market has had an average yearly growth rate of 2-3 percent.
Of these plasticizers, standard phthalate esters comprise over 85 percent of the tonnage produced every year. Phthalates command the market due to their low cost, ease of use and availability. Other common plasticizers include adipates, polymerics and trimellitates.
Over 90 percent of plasticizer volume goes into flexible PVC applications. Plasticized PVC polymer is found in a wide variety of products including food packaging, construction materials, toys, and medical devices. Yet PVC in its “true” form is a hard, brittle polymer used in PVC pipe for the construction industry.
Vestinol® 9 DINP (Diisononyl Phthalate) is a phthalate ester used mainly as a plasticizer. Plasticizers are substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are primarily used to soften polyvinyl chloride.
The development of cellulose nitrate in 1846 led to the manufacture of castor oil which was patented in 1856 for use as the first plasticizer. In 1870, camphor became the more favored plasticizer for cellulose nitrate. Phthalates were first introduced in the 1920s and quickly replaced the volatile and odorous camphor. In 1931, the commercial availability of polyvinyl chloride and the development of di-2-ehthylhexyl phthalate began the boom of the plasticizer PVC industry, the primary use of Diisononyl Phthalate, commonly referred to as DINP.
Phthalate esters are the dialkyl esters of phthalic acid. The name phthalate is derived from phthalic acid, which itself is derived from the word “naphthalene.” When added to plastics, phthalates allow the long molecules to slide against one another. The phthalates have a clear liquid consistency and show low water solubility, low oil solubility and low volatility. The polar carboxyl group contributes little to the physical properties of the phthalates, except in very small short chain moieties, such as ethyl or methyl groups. Phthalate esters are colorless, odorless liquids produced by reacting phthalic anhydride with an appropriate alcohol (usually 6 to 13 carbon atoms in length).