The word phthalate is often viewed by the public pretty negatively, and the average person often points to the reason for this as health concerns and environmental issues. You might even find yourself reaching for a bottle on the shelf labeled “phthalate-free” even if it is an item that would have never contained a phthalate in the first place. But what even is a phthalate? And do you know the difference between the various phthalates commonly used in everyday plastics and coatings?
Phthalates have been used since the 1920s, primarily to improve the flexibility and durability of plastics. They have been extensively studied in scientific research, especially more recently. It was in the 1990s that concerns first arose that phthalates could mimic hormones and act as endocrine disruptors. However, what many people don’t realize is that not all phthalates are created equal. There’s an important distinction between low molecular weight (LMW) and high molecular weight (HMW) phthalates—one that significantly affects their safety profiles and uses.
While LMW phthalates have been linked to health risks and are increasingly being phased out, HMW phthalates are generally considered to be much safer, with lower toxicity and reduced potential for bioaccumulation. HMW are larger, and so they stay embedded in the plastic, whereas the smaller LMW are a different shape and so they can sometime escape or leach out. Understanding this difference is key to having a more accurate and informed perspective on phthalates in consumer and industrial products.
High molecular weight phthalates
High molecular weight phthalates have 7 or more carbon atoms in their chemical backbone that gives them increased permanency and durability. Phthalates in this group include Diisononyl phthalate (DINP), Diisodecyl phthalate (DIDP), Dipropylheptyl phthalate (DPHP), and Diundecyl Phthalate (DUP). These chemistries find a wide variety of uses such as in vinyl roofing and wire and cable jacketing, however, they were never the class of phthalates found in personal care products.
With more than 50 years of research, phthalates are among the most thoroughly studied family of compounds in the world and have been reviewed by multiple regulatory bodies in the United States and Europe. Scientific and regulatory bodies have concluded that high molecular weight phthalates do not pose a risk to human health at typical exposure levels. Information collected by the Centers for Disease Control and Prevention during the last 10 years indicates that exposure is extremely low for HMW phthalates – significantly lower than any levels of concern set by regulatory agencies. Recently, the U.S. EPA conducted risk evaluations with testing specifically for DINP and DIDP and found that they were safe for use in almost all applications.
Learn more at: https://www.americanchemistry.com/chemistry-in-america/chemistries/high-phthalates
Low molecular weight phthalates
But then why do phthalates get such a bad reputation? Low molecular weight (LMW) phthalates differ from high molecular weight (HMW) phthalates primarily in their chemical structure, physical properties, and toxicity profiles. LMW phthalates have shorter carbon chains (typically 3 to 6 carbons), which makes them more volatile and more soluble in water and other organic solvents. They are more likely to leach out of plastics and into the air or water than the HMW phthalates. They are also the group of phthalates that were commonly used in perfumes, nail polish, cosmetics, and insect repellants.
Benzyl Butyl Phthalate (BBP) is one of four phthalates that are associated with toxic effects on reproductive health. Regulations have curtailed the once-wide distribution of BBP. In 2012, the U.S. permanently banned BBP in any amount over 0.1% by weight in children’s toys and childcare articles. It underwent EPA risk evaluation and has a CERCLA reportable quantity of 100 LBS. In 2015, leading retailers and flooring manufacturers announced they would stop using phthalate plasticizers in vinyl flooring by the end of the year. By 2019, the transition was nearly complete across the flooring industry. “Four years after environmental and health advocacy groups reported harmful phthalates in vinyl flooring sold at popular stores, recent tests show the pressure to remove these hormone disrupting compounds worked,” reported Environmental Health News in June 2019.
The European Union (EU) banned BBP in 2015 as part of the Registration, Evaluation, Authorisation & Restriction of Chemicals (REACH) law. The ban prohibits BBP in consumer products and indoor areas at concentrations of 0.1% or higher by weight. The Restriction of Hazardous Substances in Electrical and Electronic Equipment (RoHS) directive banned BBP in most electrical and electronic equipment in 2019.
Because of these regulations and the research about the endocrine disrupting abilities of LMW phthalates like BBP, many manufacturers are voluntarily phasing it out in favor of safer alternatives. Today, alternative plasticizers—such as DINCH, DOTP, and other non-phthalate options—are increasingly being used to meet performance needs while offering improved safety profiles. This transition reflects a broader commitment across industries to prioritize human health and environmental sustainability without compromising product quality.
How ChemCeed Can Help
ChemCeed offers a wide portfolio of plasticizers, including both tried-and-true HMW phthalates as well as phthalate alternatives. Our representatives are prepared to support formulators with information and data, including data on plasticizer blends, to aid in reformulation work. ChemCeed offers a variety of fast-fusing plasticizers which may be considered as an alternative for BBP.
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