Mesamoll (Alkylsulfonic Phenyl Ester): Properties, Uses in Plastics and Regulatory Status

Mesamoll is the Lanxess trade name for ASE, the alkanesulfonic acid (C10-C21) phenyl esters (CAS 91082-17-6), a non-phthalate plasticizer used in flexible PVC, polyurethane and nitrile rubber where the compound has to resist hydrolysis. Because the plasticizing group is a sulfonic acid ester rather than a carboxylic acid ester, its resistance to saponification differs from that of a phthalate, which raises the question of where that property is worth paying for.

ASE is not on the REACH Candidate List, is not restricted under REACH Annex XVII, and is not listed in Annex I of Regulation (EU) No 10/2011, checked against the consolidated text of 14 July 2026. Mesamoll is one of 87 plasticizer pages in our directory of plastic additives, each with the same identity, dosage and regulatory fields.

This page gives the identity of a UVCB substance, its plasticization mechanism, the properties that are not published, the three polymer groups and their 5 to 65 wt% class band, the saponification resistance that decides selection, a dated regulatory matrix, the comparison with DOTP, DINCH, DEHP and DINP, and the single recorded producer. Where no public value exists, this page says so instead of estimating.

Table T1. Mesamoll (ASE) identity card.

What Is Mesamoll (Alkylsulfonic Phenyl Ester)?#

Mesamoll is a mixture of phenyl esters of C10 to C21 alkanesulfonic acids, a plasticizer in the sense of ASTM D883: a substance incorporated into a plastic or elastomer to increase its flexibility, workability or distensibility. The acid side is an alkanesulfonic acid, the alcohol side is phenol, and the bond between them is a sulfonate ester rather than the carboxylate ester of every phthalate, adipate and terephthalate. That single structural difference is what the class is bought for, because the sulfonates and sulfonamides are classified in our plasticizer taxonomy by gelling behaviour and saponification resistance, not by efficiency. Which substances does the name Mesamoll actually cover?

The name covers a range of molecules, not one molecule. ASE sits in the smallest of the 14 classes on the hub for plasticizers for plastics, and inside PVC it behaves as a primary plasticizer, compatible enough to carry a compound on its own rather than only to extend another ester. The C10 to C21 span of the alkyl chain makes it a UVCB substance, the point the third question below takes up. No production route, catalyst or feedstock for ASE is recorded in our sources.

What does ASE stand for, and what is Mesamoll made of?#

ASE stands for alkylsulfonic phenyl ester, the industry short form for the alkanesulfonic acid (C10-C21) phenyl esters that ECHA lists as "sulfonic acids, C10-21-alkane, Ph esters" under EC 293-728-5. The substance is built from an alkanesulfonic acid and phenol, and PubChem records phenyl pentadecane-1-sulfonate as the representative component of CAS 91082-17-6.

Is Mesamoll a phthalate?#

Mesamoll is not a phthalate: its ester bond is formed from an alkanesulfonic acid and phenol, not from phthalic acid, so it falls outside both REACH Annex XVII entry 51 (DEHP, DBP, BBP, DIBP) and entry 52 (DINP, DIDP, DNOP). A phthalate is a diester of ortho-phthalic acid, and "non-phthalate" is the regulatory term for plasticizers that are not ortho-phthalates, a usage Eastman documents in its terephthalate literature. Mesamoll is counted among the non-phthalate plasticizers, the group regulators treat separately from ortho-phthalates.

The consequence sits in procurement rather than chemistry. A specification that excludes ortho-phthalates removes DEHP, DBP, BBP, DIBP, DINP, DIDP and DNOP from a compound and leaves the sulfonic acid ester untouched.

Why is Mesamoll a UVCB substance and not a single molecule?#

Mesamoll is a UVCB substance, a substance of unknown or variable composition: the alkyl chain runs from C10 to C21, so the formula C21H36O3S and the molecular weight of 368.6 g/mol describe one representative component rather than the whole product. Chain-length distribution is the reason two ASE grades with the same CAS number can differ in viscosity and volatility, and the reason every specification is taken from the supplier's technical data sheet. Hallstar's ester review gives the direction of that effect: a longer alcohol chain lowers polarity, which reduces compatibility and volatility and improves low-temperature flexibility. No percentage composition for CAS 91082-17-6 is recorded.

How Does Mesamoll Plasticize PVC and Polyurethane?#

Mesamoll plasticizes PVC the way every monomeric ester plasticizer does: its molecules sit between the polymer chains, weaken the dipole interactions that hold them together and lower the glass transition temperature. Once the plasticizer solvates the PVC chains, the compound gains free volume and a rigid resin becomes a flexible material at Shore A 50 to 90. Below about 15 phr the effect reverses: antiplasticization sets in and the compound turns stiffer than the unplasticized resin, which is why flexible PVC recipes run from 5 to 65 wt% total plasticizer.

The 4 classic plasticization theories are listed below, in the order Hallstar's ester review presents them.

• Lubricity theory: the plasticizer lubricates the polymer chains and cuts the friction that resists chain movement.
• Gel theory: the plasticizer breaks the gel structure formed by attraction points along the chain.
• Free volume theory: the plasticizer raises the unoccupied volume of the matrix, lowering the glass transition temperature (Tg).
• Mechanistic theory (solvation-desolvation): the plasticizer attaches to and detaches from the chain in equilibrium, so no chain stays locked.

How polar is the sulfonate group compared with a phthalate ester? Compatibility in this class is judged by the solubility parameter: a plasticizer stays compatible with a polymer when the two parameters lie within ±1.5 (cal/cm3)^0.5 of each other. No solubility parameter for ASE is recorded, so this page states the test rather than a number. The four theories and the solubility-parameter test are explained on how plasticizers work.

What Are the Physical and Chemical Properties of Mesamoll?#

Mesamoll carries a representative molecular weight of 368.6 g/mol and a representative molecular formula of C21H36O3S, and no other physical constant for CAS 91082-17-6 is published in the primary sources this site uses. No independently verified melting point, boiling point, density, viscosity, flash point or water solubility exists for this substance; request the supplier's technical data sheet, because a UVCB product carries grade-specific numbers rather than substance-wide ones.

Table T2. Mesamoll physical and chemical properties.

An unfilled row here is a statement, not an omission. The ranking results for this substance are supplier catalogues and data-sheet PDFs, each reporting the numbers of one grade; a page that copied them would publish one supplier's specification as the property of a CAS number.

Which Polymers Use Mesamoll, and at What Dosage?#

Mesamoll is used in three polymer groups: flexible PVC, polyurethane and the polar rubbers NBR and CR. Total plasticizer content in flexible PVC runs from 5 to 65 wt% for a target hardness of about Shore A 50 to 90, a class range measured by Helene Wiesinger and colleagues at ETH Zürich (Environmental Science & Technology, 2024), not a Mesamoll value. No ASE-specific loading is recorded for any of the three groups.

Table T3. Recorded polymers and dosage evidence for Mesamoll (ASE).

Blank cells mean no value exists in our verified sources. ECHA's plastic additives mapping records typical concentrations for other plasticizers, for example 10 to 35 wt% in soft PVC and PUR for pentaerythritol tetravalerate, but it holds no concentration for CAS 91082-17-6.

How do phr values convert to weight percent? Compound recipes give plasticizer levels in PHR (parts per hundred resin), which converts against the full formulation total: wt% = phr_i / total phr × 100. For example, 40 phr ASE in a compound of 100 phr PVC plus 40 phr plasticizer gives 40 / 140 × 100 = 28.6 wt%, arithmetic for the conversion and never a recommended level. Real compounds also carry stabilizers, fillers and lubricants, so the divisor is the total of every ingredient.

Mesamoll in flexible PVC#

In flexible PVC, Mesamoll works as a general-purpose plasticizer, and the property that decides its selection is not efficiency but gelling behaviour and resistance to saponification. A flexible PVC compound built on a sulfonic ester gelates and fuses like any ester-plasticized compound, and it keeps the plasticizer intact under service conditions that attack a carboxylic ester. ASE competes with DOTP, DINP and DINCH across the plasticizers for PVC range, and the choice is a service-condition decision rather than a cost-per-phr one.

No substitution factor exists for ASE in our efficiency table, which runs from DBP at 0.86 to DTDP at 1.26 against the DEHP reference of 1.00 and holds no sulfonic ester. The phr level that matches a given Shore A hardness is established on the compound, not interpolated from that table.

Mesamoll in polyurethane and TPU#

Polyurethane is the second polymer group for Mesamoll, where a plasticizer has to survive the moisture and the amine or tin catalysis that would hydrolyse a carboxylic ester. Our plasticizer dossier records alkylsulfonates for 2K polyurethane systems alongside benzoates such as DPGDB and DINP, which puts ASE in the same selection set as the fast-fusing benzoates for that chemistry. The full PU additive package is on additives for polyurethane and TPU.

No PU dosage, no compatibility limit and no catalyst-interaction figure for ASE is recorded in our sources, so this section describes the role and does not quantify it.

Mesamoll in NBR and CR rubber compounds#

Mesamoll also acts as an ester softener in the polar rubbers NBR and CR, the same group that uses DOA, DOS and DOTP, while non-polar EPDM takes paraffinic or naphthenic oils instead. Ester plasticizers serve NBR, CR and CSM compounds up to 135 °C (275 °F), and ester selection for polar rubbers is compared on plasticizers for rubber and elastomers.

What Is Mesamoll Used For in Plastics?#

Mesamoll is used in three recorded areas: flexible PVC compounds, polyurethane systems and sealants, and in each of them the reason to choose it is resistance to hydrolysis rather than plasticizing efficiency. The three areas appear below in the order our substance record lists them.

• Flexible PVC compounds, where ASE is the primary plasticizer and the article holds its properties in humid or alkaline service.
• Polyurethane systems, where the plasticizer coexists with isocyanate chemistry, moisture and amine or tin catalysis.
• Sealants, which sit outside the plastics scope of this reference and appear here only because the substance record names them.

No further application is recorded for ASE, and supplier marketing for other end uses is not repeated here until each one is verified and entered in our source library with its source. Stabilizer, filler and lubricant choices that go with a flexible PVC recipe are on additives for PVC.

How Does Mesamoll Perform? Hydrolysis and Saponification Resistance#

Mesamoll resists saponification because the plasticizing bond is a sulfonic acid ester, which does not hydrolyse under the alkaline and humid conditions that split the carboxylic ester bond of a phthalate or an adipate. Saponification is the alkaline cleavage of an ester into an acid salt and an alcohol, the route that strips a plasticizer out of a compound exposed to alkaline media, hot water or cleaning chemistry. That resistance, with gelling behaviour, is the classification criterion for the sulfonate class in our plasticizer taxonomy.

Volatility, migration and extraction are measured rather than asserted, under ASTM D1203 Methods A and B and ISO 176 for volatility, ISO 177 for migration and ASTM D1239 for extraction. ASTM D1203, ISO 177 and ASTM D1239 are explained on plasticizer migration, extraction and volatility. No volatility, migration, extraction, low-temperature or hydrolysis-rate value for ASE appears in our sources, so comparative test data are requested from the supplier for the grade in question.

Table T4. Performance indicators, test methods and data status for Mesamoll (ASE).

Buyers who search for hydrolysis resistance confuse two additives that do different jobs. A hydrolysis-resistant plasticizer such as ASE keeps the plasticizer itself intact inside the compound, while a hydrolysis stabilizer is a carbodiimide, sold in lines such as Stabaxol, that protects a polyester or polyurethane matrix against hydrolytic chain scission. A hydrolysis-resistant plasticizer is not the carbodiimide hydrolysis stabilizers that protect a polyester matrix, and a specification needing both names both.

How Does Mesamoll Interact with Other Plasticizers and Additives?#

Mesamoll is normally one component of a plasticizer package rather than the whole of it, because a single ester rarely covers gelation, low-temperature flexibility and permanence at once. Compatibility between the components is judged by the same solubility-parameter window of ±1.5 (cal/cm3)^0.5 that governs the polymer, and DOTP and DINCH are the partners our record names. Three blending roles apply to a specialty ester such as Mesamoll, following the functional groups Hallstar uses.

• Low-temperature esters (monomerics), holding flexibility at sub-zero service temperatures.
• High-temperature esters (trimellitates and pentaerythritol esters), where heat ageing and low volatility decide the compound.
• Permanent esters (polymerics), where extraction and migration resistance outrank processability.

Co-additives change the arithmetic of a PVC recipe too. ESBO (epoxidized soybean oil) works at 1 to 2 wt% as a co-stabilizer and at 25 to 45 wt% as a main plasticizer, a split documented by Czogała and colleagues in 2021, so a recipe carrying ESBO also carries part of its plasticizer load. No blend ratio, synergy or antagonism is recorded for ASE, so every sentence here states the general rule.

What Is the Regulatory Status of Mesamoll?#

Mesamoll is not a Substance of Very High Concern, is not subject to authorisation under REACH Annex XIV, is not restricted under REACH Annex XVII, is not a persistent organic pollutant and is not listed in Annex I of Regulation (EU) No 10/2011 (status 23 September 2026). The matrix gives each instrument, the status of CAS 91082-17-6 under it and the reference checked.

Table T5. Regulatory matrix for Mesamoll (ASE, CAS 91082-17-6), status 23 September 2026.

Three cells are open rather than negative, and the difference matters inside a compliance file. The REACH registration status and tonnage band could not be read from the ECHA dossier system on 23 September 2026, and the US FDA and Proposition 65 cells are unresolved, so all three read "being verified" instead of "not listed". Which plasticizers carry an FCM number is tabulated on plasticizers in food contact materials.

Is Mesamoll REACH registered, and is it an SVHC?#

Mesamoll is not a Substance of Very High Concern: ASE (CAS 91082-17-6) is absent from the REACH Candidate List as of 23 September 2026, unlike DEHP, which has been on it since 28 October 2008. Its REACH registration status and tonnage band are a different question, and one this page does not answer: ECHA's dossier system blocked automated access at the last check, so no tonnage band is stated and the word "unregistered" is not used.

DEHP has been on the SVHC Candidate List since 28 October 2008; ASE has never been added. Market presence is not evidence of a registration, so the two rows of the matrix stay apart.

Is Mesamoll allowed in food-contact plastics?#

Mesamoll is not authorised for EU food-contact plastics: alkanesulfonic acid (C10-C21) phenyl esters carry no FCM number in Annex I of Regulation (EU) No 10/2011, checked against the consolidated text of 14 July 2026, and only substances on that Union list may be used as additives in plastic food-contact materials. The Union list principle and group restriction 32, the plasticisers group with an SML(T) of 60 mg/kg covering FCM 8, 72, 73, 138, 140, 157, 159, 207, 242, 283, 532, 670, 728, 729, 775, 783, 797, 798, 810, 815, 1078 and 1085, are set out on EU 10/2011.

Lanxess markets a second grade, Mesamoll II, in the food-contact context; because that grade's identity and its EU listing are not resolved in our sources, this page states the status of CAS 91082-17-6 only. US food-contact status: being verified. No 21 CFR section and no food contact notification number is recorded for this CAS number, and "FDA approved" is never written without one.

What is the US status of Mesamoll under TSCA, FDA and Proposition 65?#

Mesamoll is reported under the US Chemical Data Reporting rule of the Toxic Substances Control Act, which means US manufacturers and importers report its volumes to the EPA. Reporting under that rule is an inventory obligation and not a safety conclusion, and how Chemical Data Reporting differs from a risk evaluation is set out on TSCA and plastic additives.

US food-contact status under the FDA is being verified: our sources hold no 21 CFR citation and no food contact notification number. Proposition 65 status is being verified too, and this page states neither "listed" nor "not listed" until the current OEHHA list has been checked against CAS 91082-17-6.

Is Mesamoll Safe? Health, Safety and Environmental Profile#

Mesamoll has no harmonised hazard classification under the EU CLP Regulation (EC) No 1272/2008, and all 101 companies that notified ASE to ECHA's classification and labelling inventory report that it does not meet the GHS hazard criteria. A self-classification is not a toxicological assessment: no LD50, no NOAEL, no endocrine screening result and no biodegradation figure for CAS 91082-17-6 appears in the primary sources this site uses, so the honest summary is "not classified as hazardous, and thinly studied in public".

The three parts of the public safety picture are listed below.

• Harmonised classification: none under CLP Regulation (EC) No 1272/2008.
• Industry notifications: 101 of 101 notifying companies report "not classified" in the ECHA C&L Inventory, which is self-classification.
• What is not known: acute and repeat-dose toxicity endpoints, endocrine screening data, biodegradation figures.

Concern about ortho-phthalates does not transfer automatically to a sulfonic ester, because the reproductive-toxicity findings behind the phthalate restrictions attach to the monoester metabolites of ortho-phthalic acid. The concern summarised on phthalates: health effects applies to ortho-phthalates, not to sulfonic esters, and the absent data set for ASE is a gap rather than a clearance.

What Are the Alternatives to Mesamoll?#

The two alternatives recorded for Mesamoll are DOTP and DINCH, the general-purpose non-phthalate esters that replace it wherever hydrolysis resistance is not the deciding property. The table sets both against the ortho-phthalate benchmarks DEHP and DINP, on the fields a formulator and a compliance officer check first.

Table T6. Mesamoll compared with DOTP, DINCH, DEHP and DINP.

Substitution factors are typical values from one secondary source, with DEHP as the 1.00 reference. No substitution factor is published for ASE.

Full property data for the alternatives sit on the plasticizer comparison page, where the same five substances are set beside TOTM and the citrate esters.

Mesamoll vs DOTP#

DOTP is the better choice for general-purpose flexible PVC and the only one of the two that is authorised for EU food-contact plastics, while Mesamoll is selected for compounds that have to survive alkaline or humid service. DOTP is a terephthalate of CAS 6422-86-2, molecular weight 390.6 g/mol, with a typical substitution factor of 1.03 against DEHP, a near one-for-one swap in an existing phthalate recipe; ASE carries no published substitution factor.

The food-contact split is the plainest difference between the two. DOTP / DEHT (dioctyl terephthalate) carries FCM 798 with an SML of 60 mg/kg under Regulation (EU) No 10/2011, and ASE carries no FCM number, so a food-contact article closes the comparison before a property is measured.

Mesamoll vs DINCH#

DINCH is the alternative for sensitive applications: it is listed in Annex I of Regulation (EU) No 10/2011 as FCM substance 775 and is used in medical devices and toys, two areas where an unlisted substance such as Mesamoll cannot follow it. DINCH is the hydrogenated form of DINP, CAS 166412-78-8 with the US product registered as 474919-59-0, molecular weight 424.7 g/mol, no individual SML and group restriction 32. DINCH (Hexamoll DINCH) is the alternative for medical devices and toys, and its hydrogenated cyclohexane ring gives lower polarity and better low-temperature flexibility, at the cost of solvating power.

Mesamoll vs DEHP and DINP#

Mesamoll replaces the ortho-phthalates on regulatory grounds rather than on performance: DEHP carries a harmonised Repr. 1B classification (H360FD), sits on the Candidate List since 28 October 2008 and is limited to 0.1 % in the plasticised material of all articles under REACH Annex XVII entry 51, while ASE appears in neither entry 51 nor entry 52. DEHP (DOP, dioctyl phthalate) also holds Annex XIV entry 4 with a sunset date of 21 February 2015; ASE holds no authorisation entry.

DINP is the working comparison rather than the restricted one. Annex XVII entry 52 restricts it only in toys and childcare articles that children can put in the mouth, so DINP is not banned in the EU. DINP (diisononyl phthalate) is restricted only in mouthable toys and childcare articles, which leaves the case for ASE resting on saponification resistance and on specifications that exclude ortho-phthalates.

Who Manufactures Mesamoll? Grades and Suppliers#

Mesamoll is a Lanxess trade name: the Cologne-based additive producer sells it alongside its Adimoll, Unimoll, Ultramoll and Uniplex plasticizer lines. Lanxess is the only manufacturer recorded for ASE in our source library, and it assembled its present additive portfolio in part through the Chemtura acquisition completed on 21 April 2017. Mesamoll sits beside Adimoll and Unimoll in the Lanxess plastic additives portfolio.

ASE reaches compounders through distributors and repackagers, which is why catalogue listings and drum offers dominate the results behind the Mesamoll manufacturer and Mesamoll supplier queries. A distributor is not a producer, and none is named here as one. A second ASE offer appears under another brand name and stays unverified until its producing entity is confirmed.

No verified price figure for ASE exists in our data, so none is printed. Price in this class follows the ester feedstock chain, freight and the regional balance between phthalate and non-phthalate capacity, drivers tracked on plasticizer prices. Buyers should request the supplier's technical data sheet (TDS) and safety data sheet (SDS) and a statement of the chain-length specification, because ASE is a UVCB substance.

Table T7. Producers and sources of ASE.

Producers by region and product line are listed in the directory of plasticizer manufacturers.

How Do Sulfonic Esters Fit into the Plasticizer Family?#

Mesamoll is the PVC and polyurethane member of the sulfonic ester and sulfonamide class, the smallest of the 14 plasticizer classes and the only one whose plasticizing bond is not a carboxylic ester. The class holds two substances that matter in plastics: ASE for PVC and polyurethane, and BBSA for the polyamides. Both sit far from the centre of a market that European Plasticisers puts at 8.4 million tonnes a year globally, with more than 85 % of European plasticizer volume going into flexible PVC. The class sits beside 13 others on the hub for types of plasticizers.

BBSA and the sulfonamide plasticizers#

The second member of the class is N-butylbenzenesulfonamide (BBSA, CAS 3622-84-2), the standard plasticizer for polyamide 11 and polyamide 12 tubing at 10 to 15 wt%. BBSA carries EC 222-823-6, the formula C10H15NO2S and a molecular weight of 213.30 g/mol, and its C&L notifications name H373 and H412, a different hazard profile from the unclassified ASE. BBSA (N-butylbenzenesulfonamide) plasticizes PA11 and PA12 at 10 to 15 wt%, mostly in fuel and air-brake tubing.

Mesamoll II and other Lanxess plasticizer grades#

Lanxess sells a second grade under the name Mesamoll II, and the difference between the two grades is the most frequent related search on this entity. What is verified is that the grade exists. Its CAS number, its composition and its relation to CAS 91082-17-6 are not resolved in our sources, so its regulatory status is stated here in neither direction. Two documents would close the question: the Lanxess technical data sheet for that grade, and the Annex I entry of Regulation (EU) No 10/2011 that it does or does not hold.

"Mesamoll oil": uses outside plastics#

Searches for "Mesamoll oil" do not all mean the plastics additive: the results for that phrase include equipment-maintenance fluids rather than compounding ingredients. The identity of the products sold under that name is not established in the sources this page uses, so none of them is described, named or linked. This reference covers additives for plastics, and a maintenance fluid for spray and pump equipment sits outside that border.

Is Mesamoll banned anywhere?#

No: Mesamoll is not banned or restricted under the EU, US or other rules covered on this page, and the only restriction that touches it is the EU food-contact rule, which excludes it by not listing it (status 23 September 2026). Entries 51 and 52 are explained on REACH Annex XVII restrictions, and neither of them names the substance.

Does Mesamoll need an SDS?#

Yes: suppliers provide a safety data sheet for Mesamoll as for any traded chemical, even though ASE carries no harmonised CLP classification and 101 of 101 notifiers report it as not classified. A data sheet showing no hazard classification in section 2 still records identity, handling and storage.

Is Mesamoll the same as a concrete plasticizer?#

No: concrete plasticizers are water-reducing admixtures such as lignosulfonates and polycarboxylate ethers, a different product class from the ester plasticizers that soften plastics, and this reference covers the plastics class only. A concrete plasticizer reduces the water needed for a given workability; an ester plasticizer lowers the glass transition temperature of a polymer.

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