DINP is a general-purpose phthalate plasticizer that can make up the whole plasticizer loading of a flexible formulation, and TXIB is a low-viscosity non-phthalate additive that replaces a few phr of the primary plasticizer to thin a plastisol. In the finished PVC, TXIB is lost much faster to heat and water, and DINP much faster to oils and hydrocarbon solvents.
DINP has the larger toxicology record and the more serious findings. Both the EU and the US cap it at 0.1% in children’s toys and childcare articles (in the EU, only those a child can put in its mouth), and since June 2026 IARC has classified it as possibly carcinogenic to humans.
TXIB has low acute toxicity but no chronic or carcinogenicity study on record, and its food-contact approvals are narrow: single-use gloves in the EU and, for PVC food contact in the US, only Eastman’s own TXIB.
What Is TXIB
TXIB is 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (CAS 6846-50-0), a non-phthalate diester of a branched glycol and isobutyric acid with a molecular weight of 286.4. Eastman sold it as TXIB plasticizer until 2006 and has marketed it since as TXIB formulation additive. In PVC it goes into plastisols, sheet vinyl flooring, vinyl gloves, toys and wall coverings.
What Is DINP
DINP (diisononyl phthalate) is a general-purpose primary plasticizer for flexible PVC, a high-molecular-weight ortho-phthalate made by esterifying phthalic anhydride with isononyl alcohol. Most of it goes into wire and cable, film and sheet, flooring, hoses, footwear, toys and food-contact plastics.
Commercial DINP is an isomer mixture: the EU defines it as the diesters of phthalic acid with branched C8–C10 alcohols, more than 60% of them C9, and its molecular weight is about 418.6. It is registered under two CAS numbers, 28553-12-0 and 68515-48-0, and the restrictions on DINP cover both.
The Difference Between TXIB and DINP
Role in a PVC Formulation
DINP is a primary plasticizer that can soften a flexible PVC formula on its own; TXIB is an additive that goes in beside a primary plasticizer and takes over part of its loading. In Eastman’s DINP plastisols, TXIB replaces 5 or 10 phr of a 50 phr plasticizer total.
Plasticizing Efficiency
Neat, TXIB is the less efficient plasticizer. In one published test series that ran both at 67 phr in the same resin, TXIB gave Shore A 76 against 73 for DINP.
In the blends TXIB is actually used in, hardness does not change: replacing 5 or 10 phr of a 50 phr DINP loading with TXIB kept Eastman’s plastisols at Shore A 80.
Plastisol Viscosity
TXIB lowers plastisol viscosity, which is what it is added to DINP for. Neat, TXIB measures 9 cP at 25 °C and DINP about 55 cP at the same temperature, although the two values come from different laboratories and methods.
In Eastman’s DINP plastisols, the Brookfield viscosity fell further with each step of TXIB, from none to 5 to 10 phr, and the TXIB-free paste thickened more over 14 days of ageing. TXIB does not speed up gelation.
Volatility and Extraction
DINP stays in the finished PVC far better under heat and in water, and TXIB far better against oils and hydrocarbon solvents. In the same published 67 phr test series, the water extraction loss was 2.83% for TXIB against 0.07% for DINP.
Blends show the same two-way difference: in Eastman’s tests, replacing 10 of 50 phr of DINP with TXIB raised the loss over activated carbon from 1.4% to 4%, while the losses to hexane and cottonseed oil fell.
Toxicity
DINP’s toxicology record is extensive and shows effects on the liver and on fetal testosterone in rats, and liver tumours in rodents. TXIB’s shows low acute toxicity, but the long-term studies that would settle its chronic hazard are missing.
The EU’s risk assessment committee concluded in 2018 that DINP’s effects on fetal testosterone, which were reversible and caused no malformations, did not justify classifying it as toxic to reproduction. In June 2026, IARC classified DINP as possibly carcinogenic to humans (Group 2B); the evidence in humans was inadequate.
In-vitro genotoxicity tests on TXIB were negative. A 2009 Dutch review of TXIB in toys put its margin of safety above 100, the margin normally required, and concluded that the available data indicate no risk, and that more experimental evidence would strengthen that conclusion.
Regulatory Status
DINP is capped at 0.1% in children’s toys and childcare articles in the US, and in the EU in those a child can put in its mouth, and its food-contact use is limited by article and food type. TXIB falls outside the toy limits, which list phthalates only, but its food-contact approvals are narrow.
- Toys and childcare articles: In the EU, REACH Annex XVII Entry 52 bars more than 0.1% DINP, by weight of the plasticized material, in toys and childcare articles that children can put in their mouths. In the US, 16 CFR 1307 prohibits more than 0.1% DINP in any children’s toy or child care article, mouthable or not.
- EU food contact: Regulation (EU) No 10/2011 authorises TXIB only in single-use gloves, with a specific migration limit of 5 mg/kg. DINP is allowed as a plasticizer in repeated-use articles and in single-use articles for non-fatty food other than infant and follow-on formula, and its migration is capped at 1.8 mg/kg together with DIDP.
- US food contact: 21 CFR 178.3740 allows DINP at up to 43% of PVC no thicker than 0.005 inch that contacts certain food types at room temperature. TXIB’s CFR listings cover only cellulosic plastics and cellophane coatings. Its use in PVC food-contact articles rests on two food contact notifications, which are effective only for TXIB made by Eastman.
- California Proposition 65: DINP has been listed as a carcinogen since 2013, and a product that exposes consumers to more than 146 µg per day needs a warning.
- US TSCA: EPA’s final risk evaluation of DINP, released in January 2025, found unreasonable risk only to workers spraying DINP-containing adhesives, sealants, paints and coatings, and listed plastics product manufacturing among the uses that do not contribute to it.
- Japan indoor air: Japan has set no indoor-air guideline value for TXIB, and the health ministry’s 2024 draft assessment judged the risk at measured indoor levels not high.
How to Choose the Right One
Use DINP as the primary plasticizer wherever a phthalate is allowed, and add TXIB at a few phr when a DINP plastisol needs to be thinner.
- Plastisols that must pour, pump or fill fine mould detail: DINP with TXIB replacing 5 to 10 phr of it. The lower viscosity also lets the plastisol take more filler at the same viscosity, which can lower the formulation cost.
- Toys and childcare articles: Neither on its own. The 0.1% cap rules out DINP as the plasticizer (in the EU, only in articles a child can put in its mouth), so the formula needs a non-phthalate primary plasticizer such as DOTP. TXIB can still thin the plastisol, though its toy-safety assessment rests on limited data.
- Vinyl flooring: DINP. California has issued safe use determinations for DINP in vinyl flooring, covering residents and installers, and TXIB adds emissions from the finished floor.
- Parts that see heat or water in service: DINP without TXIB, or with as little as the viscosity allows.
On environmental fate, TXIB is inherently biodegradable and has a low bioconcentration factor, 5.2 to 31 in carp, against 1,500 for DINP.