INSPITE OF BEING PHTHALATE PLASTICIZERS, WHY DINP AND DOTP ARE SAFE FOR HUMANS COMPARED TO DOP?

Introduction:

DOP, one of the most widely used general purpose ortho phthalate plasticizer for PVC, is on its way out due to health concerns and banned in PVC products for food packaging or health care applications.

Attempts are made to manufacture alternative phthalate plasticizers without the toxicity like DOP.

Ortho phthalates plasticizers and environmental concerns:

Ortho-phthalates are manufactured by reacting phthalic anhydride with alcohol(s), ranging from methanol and ethanol (C1/C2) up to tridecyl alcohol (C13). For example - DBP, DOP, DTDP etc.

Ortho-phthalates are broadly divided into two main categories as:

1.???Low molecular weight (LMW) ortho phthalates, and

2.???High molecular weight (HMW) ortho-phthalates.

They have very different applications, toxicological properties, classification and legal requirements.

DEHP or DOP falls under low molecular weight ortho phthalate category (LMW) and is classified under 1B category of REACH.

The latest amendments now require all types of products containing the plasticizers like BBP, DBP, DEHP, and DIBP (LMW) to meet the requirements limiting the quantity of restricted phthalates in any item to?less than 0.1% (1000 ppm) of the entire article’s composition.

On the other hand, DINP and DIDP comes under High molecular weight ortho phthalate category (HMW) or high ortho-phthalates category. These HMW ortho phthalates have been registered for REACH and do not require any classification for health and environmental effects, nor they are on the Candidate List for Authorization.

Commercial Di-Iso-Nonyl Phthalate (DINP) is a mixture of phthalates with branched alkyl side chains of varying lengths e.g. ?C8, C9 and C10, having molecular weight 446.

DINP and DOTP are perfect plasticizers for replacing DOP:

?DINP (Di-Iso-Nonyl Phthalate) and DOTP (Di octyl terephthalate), have the same softening effect as DOP (efficiency factor 1.03). At the same time, both products have been classified as unobjectionable. In the case of DINP there is one exception, the presence of DINP in toys and baby articles should be avoided according to 2006 / C 90/04.

?When DOP, DINP and DOTP are phthalates, why DOP is the victim?

One would argue that since DOP, DINP and DOTP have a word phthalate, they should be banned. However, though DOTP and DINP have a word phthalate, in the chemical sense, they do not belong to the category of harmful phthalates, as explained below.

Difference between DOP, DINP and DOTP:

The?difference is clearly evident from their chemical structure.

?While DOP and DINP are ortho phthalates, DOTP is para phthalate.

In structures of DOP and DINP, one can see that the ester radicals are positioned side by side in ortho position, on the benzene ring.

When we compare DOP and DINP structures, in contrast to DOP, the ester portion in DINP is branched and occupies much more space than n-octanol in DOP. As a result of this, the migration of DINP from the PVC product is reduced or prevented and the accumulation of DINP in the environment is not possible.

In DOTP, in contrast?to?DOP, the ester radicals are not only branched but are additionally arranged on opposite sides, in the para position, of the benzene ring.

The molecular structures of DOTP and DINP occupy more space spatially. This prevents the migration of both molecules from the material, and they are not enriched in the environment. Therefore, they are considered as safe for humans.

Thus, DOTP appears to be better than DINP in terms of replacing DOP in PVC products, from safety point of view.

Difference between Phthalates and Terephthalates:

Phthalates are esters of phthalic acid.

Terephthalates are esters of terephthalic acid, which is an isomer of phthalic acid. While both belong to the same family of chemicals, they have different structures. DOTP is considered as a non-phthalate plasticizer.

So, while DOTP shares a structural similarity with phthalates, it is distinct in its chemical composition and properties, making it a safer, non-phthalate alternative.

?Features of DOTP:

?DOTP plasticizer is almost colorless low viscosity liquid.

?The viscosity is 410 MPa.s (at 0°C), 63 MPa.s (at 25°C), and 5 MPa.s (at 100°C).

?Freezing point is (-) 48℃. Boiling point is 383℃ and the ignition point is 399℃.

Compared with the commonly used di octyl phthalate (DOP), DOTP has the advantages of heat resistance, cold resistance, low volatility, resistance to extraction, flexibility, electrical insulation properties, and shows excellent durability in products. Besides, it has resistance to soapy water. In addition, DOTP can also be used for the production of artificial leather films.

?Use in cables:

Because of its low volatility, the use of DOTP can meet the temperature resistance requirements of wires and cables in totality, and can be widely used in 70°C - resistant cable materials (IEC standard of the International Electrotechnical Commission).

Versatility of DOTP:

DOTP has excellent compatibility and can also be used as a plasticizer for acrylonitrile derivatives, polyvinyl butyral, nitrile rubber, nitrocellulose,

synthetic rubber, paint additives, precision instrument lubricants, lubricant additives, and as a softener for paper.

DOTP is also used in high-quality lubricants or lubricating additives for furniture and interior decoration paints, coatings and precision instruments, nitro varnish additives, paper softeners, polyester amide biaxially stretched films, film plastic crafts, plasma storage bags, etc. It is a versatile plasticizer.