IRON TALLATE

CAS: 61788-81-6 DRYING AGENT

Iron tallate (CAS 61788-81-6) is a drying agent formed from tall oil fatty acids and iron salts, used primarily as a metallic drier in coatings for food contact applications under specific regulatory conditions.

What It Is

Iron tallate is a chemical compound identified by CAS number 61788-81-6 that functions as a drying agent in industrial and specific food contact applications. It is composed of tall oil fatty acids reacted with iron salts, yielding a mixture rather than a single discrete molecule. Commercial preparations typically include both ferrous and ferric forms of the iron salt of tall oil fatty acids. The tall oil fatty acids themselves are derived from the byproducts of pine wood pulp production and comprise a mixture of fatty acids, including oleic and linoleic acids. As a drying agent, iron tallate accelerates the curing process of oleoresinous coatings, such as those used to line metal cans and other food contact surfaces. These coatings help protect food from direct contact with metal, where the drying agent contributes to forming a solid, durable film. Iron tallate and its related preparations are not typical food ingredients ingested for nutritional or flavor purposes. Instead, they serve a technological role in the coating materials applied to packaging that may contact food. Because of variability in composition, iron tallate is best understood as a class of metallic drier additives that share functional characteristics rather than a single defined molecular entity.

How It Is Made

The production of iron tallate begins with tall oil, a complex mixture of fatty and resin acids obtained as a byproduct from the kraft pulping process in pine wood pulp mills. Tall oil itself contains a range of fatty acids, with oleic and linoleic acids making up the majority. In the manufacturing process, these fatty acids are reacted with iron salts under controlled conditions to produce the iron tallate mixture. This reaction yields a complex blend of iron-bound fatty acid salts that constitute the metallic drier. Commercial preparations may contain both ferrous and ferric salts, and the final composition will depend on the source of tall oil and specific manufacturing conditions. Because tall oil is a mixture of multiple fatty acids rather than a single compound, the exact chemical profile of iron tallate can vary from batch to batch. Manufacturers often monitor quality through standard chemical and physical property measurements, such as viscosity and iron content, to ensure consistent performance as a drying agent. The resulting iron tallate product is typically a dark-colored material that can be incorporated into resinous coatings used for food-contact surfaces. The manufacturing process for iron tallate is industrial in nature and involves careful handling of raw materials to ensure that the product meets specifications required for its intended functional use.

Why It Is Used In Food

Iron tallate is used in food-related contexts not as a nutrient or flavoring agent, but as a component of food contact coatings where it acts as a drying agent. In coatings applied to the internal surfaces of cans and other packaging, iron tallate helps accelerate the curing time of the coating resin, promoting the formation of a solid, continuous film. This cured film serves as a barrier between the metal substrate and the food product, helping to maintain the integrity of the packaging and reduce potential interaction between the metal and its contents. Its inclusion in specific regulatory listings for indirect food additives reflects this technological purpose. Regulatory references such as 21 CFR 175.300 and 21 CFR 181.25 authorize certain substances, including iron tallate, for use in coatings and as driers under defined conditions. These regulations pertain to indirect food additives – substances that may be present in food due to migration from food contact materials, not because they are added directly to food formulations. The use of iron tallate within these regulatory frameworks is intended to support safe packaging performance while minimizing unintended exposure to food consumers.

Adi Example Calculation

Because no specific ADI for iron tallate has been identified in the JECFA or EFSA regulatory resources, this section does not present a numeric example calculation. In general, ADI calculations involve multiplying the ADI by a hypothetical body weight to determine allowed intake, but without an established ADI for this compound, an illustrative calculation cannot be provided. The regulatory focus for iron tallate in food contact applications lies in setting safe conditions of use that minimize potential migration into food rather than in prescribing a numeric daily intake limit.

Safety And Health Research

Technical assessments of substances like iron tallate in the context of food contact materials focus on potential migration to food, exposure scenarios, and toxicological endpoints relevant to consumer safety. For indirect food additives, regulatory agencies evaluate available data on composition, migration potential, and toxicology to determine whether conditions of use are acceptable. The information available from substance inventories and regulatory listings documents functional use and authorized conditions rather than detailed toxicological data. Publicly accessible toxicological profiles specific to iron tallate are limited. Because iron tallate is a mixture and not a single well-defined chemical entity, detailed hazard data specific to the mixture may not be systematically published in open regulatory databases. Rather, safety evaluations performed by agencies consider the substance within the context of its intended use as part of coatings, and any risk assessment focuses on whether migration from contact surfaces could lead to consumer exposure that exceeds safety thresholds. At least in the United States, the presence of iron tallate in specific parts of the indirect additive regulations reflects the conclusion that, under specified conditions of use, it can be used safely within food contact materials.

Regulatory Status Worldwide

In the United States, iron tallate appears in the FDA food-contact substance inventory under regulations relevant to indirect additives used in coatings. Specifically, it is d in references to 21 CFR 175.300, which covers resinous and polymeric coatings authorized for use in contact with food, and 21 CFR 181.25, which lists certain prior-sanctioned substances used as driers. These listings indicate that iron tallate is permitted for use under defined conditions of use and must comply with the regulatory requirements specified in those sections of the Code of Federal Regulations. The presence of iron tallate in these regulatory listings means that its use in food contact materials is subject to conditions that help ensure safety. At the international level, a comprehensive JECFA evaluation specific to iron tallate could not be identified in searchable summary resources, and no explicit Acceptable Daily Intake (ADI) or food additive specification was found in the JECFA database by CAS number or name at the time of this writing. Information on evaluations by European authorities such as EFSA specific to iron tallate is also not readily found in publicly accessible summary resources, and therefore its formal status outside the US for food contact uses may be governed by regional regulations pertaining to indirect additives rather than explicit additive approvals. Where such regional evaluations exist, they would be documented in appropriate regulatory databases maintained by those governments or agencies.

Taste And Functional Properties

Iron tallate itself does not contribute taste or flavor in the context of food consumption, as it is not intended to be present in food at sensory-active concentrations. In general, drying agents like iron tallate are optimized for performance in coatings rather than organoleptic properties. In functional terms, iron tallate is insoluble or only slightly soluble in water, given its derivation from hydrophobic tall oil fatty acids. Its solubility characteristics make it compatible with organic resin systems where it can become evenly distributed and contribute to the drying kinetics of the coating. As a metallic drier, iron tallate influences how fast and how completely resin systems harden after application. This effect is crucial for achieving a coating with desirable mechanical properties, such as hardness, flexibility, and adhesion to the substrate. In typical conditions of use, its functional properties are evaluated based on how it affects the curing profile of the coating formulation, particularly in response to heat and exposure to air. Because iron tallate does not provide any intended flavor or nutritional value, its sensory contribution is considered negligible in properly formulated and regulated food contact applications.

Acceptable Daily Intake Explained

For direct food additives and contaminants, regulatory bodies like JECFA and EFSA often establish an Acceptable Daily Intake (ADI) based on toxicological studies. The ADI represents a daily exposure level that is considered safe over a lifetime, usually with safety factors applied. In the case of iron tallate, no specific ADI published by an authoritative body such as JECFA or EFSA was identified in available regulatory databases. Consequently, in regulatory frameworks where Iron tallate is authorized for indirect uses in food contact materials, safety considerations rely on conditions that limit migration and exposure rather than an explicit ADI value. When an ADI is defined for a substance, it is typically based on toxicological data such as chronic feeding studies in animals and consideration of endpoints like organ toxicity and reproductive effects. If a regulatory agency were to establish an ADI for iron tallate, it would be documented in the official evaluation. Without such a published ADI in authoritative sources, exposure assessment for iron tallate centers on whether any migration from coatings to food remains below levels of concern under approved conditions of use.

Comparison With Similar Additives

Iron tallate can be compared with other metallic drying agents used in coatings, such as cobalt or manganese salts of fatty acids. These additives also function to accelerate curing of resin systems in industrial applications. While iron tallate is derived from tall oil fatty acids combined with iron, other metallic driers have different metal centers and may vary in activity, compatibility with resin systems, and regulatory status. For example, cobalt-based driers are commonly used in paints and coatings for non-food applications and have distinct regulatory considerations. In the context of food contact materials, additives selected for drying functions must meet applicable regulatory requirements for indirect additives. Iron tallate’s authorization in specific sections of the US Code of Federal Regulations illustrates its role within a defined regulatory framework.

Common Food Applications Narrative

In the world of food packaging and processing, many additive substances are not added directly to food but are incorporated into materials that contact food during storage, preparation, or consumption. Iron tallate is one such additive with a specialized role. Rather than being a direct ingredient within food formulations, iron tallate is used as a drying agent in resinous coatings applied to the inside of metal cans and similar packaging systems. These coatings provide a barrier that protects canned foods from corrosion and contamination while maintaining food quality. When a manufacturer applies a coating to the interior of a can, the liquid coating must dry and cure effectively to form a uniform, adherent layer. Iron tallate helps facilitate this curing process by accelerating the drying of the resin, enabling efficient production line operations and ensuring that the finished packaging performs as expected. The use of iron tallate in coating formulations underscores the additive’s importance in food packaging technology, even though consumers never see it listed as a direct food ingredient. Instead, its contribution is behind the scenes, supporting the safety and performance of packaging materials that come into contact with a wide range of foods.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 175.300 and 21 CFR 181.25

EFSA

  • Notes: EFSA authorization status not identified in available regulatory databases

JECFA

  • Notes: JECFA evaluation specific to this compound not found in available summaries

Sources

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