Glycerol Monostearate: Properties, Uses in Plastics and Regulatory Status

Glycerol monostearate (GMS, CAS 31566-31-1) is a glycerol fatty acid monoester used in plastics as a migrating antistatic agent, as an antifog and anti-drip agent, and as an internal lubricant for PVC. One additive covering 3 jobs raises the question of how a single monoester does all three, and the answer is the same in each case: it migrates out of the melt to the surface. Its molecular formula is C21H42O4, its molecular weight 358.6 g/mol and its systematic name 2,3-dihydroxypropyl octadecanoate.

GMS and ethoxylated amines together account for more than 50 % of the antistatic additive market, a share reported in the journal Polymers in 2023, and GMS is authorised for EU food-contact plastics as FCM substance 53 under Regulation (EU) No 10/2011 with no specific migration limit. GMS is one of 437 substance profiles in our directory of plastic additives, each with the same identity, dosage and regulatory fields.

Six figures organise everything below: 3 functions from one migration mechanism, 0.05 to 0.6 % (w/w) in polyolefins against 0.5 to 1.5 phr in PVC, 6 applications, a service life of about 1 to 2 months, one EU FCM number against one US 21 CFR section, and 7 producers.

The identity table below collects the numbers a specification, a REACH check and a food-contact declaration ask for.

What Is Glycerol Monostearate (GMS)?#

Glycerol monostearate is the monoester of glycerol and stearic acid: one of glycerol's 3 hydroxyl groups carries a C18 fatty acid chain, and the 2 that stay free make the molecule amphiphilic. That construction places GMS in the class of glycerol fatty acid monoesters, which behave as non-ionic surfactants. Why does a half-polar, half-fatty structure matter inside a polymer?

Amphiphilic structure decides where the molecule ends up. The C18 stearate tail dissolves in a polyolefin or PVC matrix during compounding, the polar glycerol head with its 2 free hydroxyl groups does not, and the mismatch drives the monoester to the surface, where the tail anchors in the bulk and the hydroxyl groups face the air. GMS is the highest-volume of the non-ionic antistatic agents for plastics, the family hub that compares the migrating, permanent, conductive-filler and ionic classes side by side.

What is GMS additive, and is it the same as glyceryl monostearate?#

GMS stands for glycerol monostearate, and glyceryl monostearate, monostearin and glycerol 1-stearate are the same substance under different naming conventions, not different additives. The naming splits by audience: "monostearin" is the title PubChem uses for CID 24699, "glyceryl monostearate" is the form the US FDA and the cosmetic ingredient lists use, and "glycerol monostearate" is the form the polymer industry and the supplier data sheets use. Four further synonyms describe the same material, among them 2,3-dihydroxypropyl octadecanoate, 1-glyceryl stearate, stearic acid monoester with glycerol and glycerin 1-monostearate.

Which CAS number is correct for glycerol monostearate?#

The primary CAS number for glycerol monostearate is 31566-31-1 (EC 250-705-4), while 123-94-4 (EC 204-664-4) denotes the 1-monostearate isomer and 91052-47-0 covers the commercial mixture registered as Glycerides, C16-18 mono-. The 3 numbers are not interchangeable on a specification sheet, because a commercial GMS grade is rarely a single isomer: it is a mixture of mono-, di- and triglycerides, which is why 2 separate REACH registration entries exist for what a buyer calls one product. A purchase specification that quotes only 31566-31-1 therefore describes the substance rather than the delivered material.

GMS 40, GMS 60 and GMS 90: what does the grade number mean?#

The grade number is the monoglyceride content: a GMS 40 grade such as STRUKTOL TR 151-40 contains 40 to 45 % monoglyceride, with the balance made up of di- and triglycerides and free glycerol. Baerlocher describes Baerolub L-MS in the same band, as an approximately 40 % monoglyceride type. Monoglyceride content also moves the melting behaviour, so the verified ranges differ by grade: 58 to 60 °C (136.4 to 140 °F) for TR 151-40, 56 to 62 °C (132.8 to 143.6 °F) for the approximately 40 % Baerlocher type and 54 to 65 °C (129.2 to 149 °F) for LIGALUB 11 GE from Peter Greven.

Higher-monoglyceride grades, commonly sold as GMS 90 or GMS 95, are offered by the same producers. Their specifications are not covered by a primary source on file and are not reproduced here, and the same applies to what the word "distilled" guarantees on a GMS label.

What Does Glycerol Monostearate Do in a Plastic?#

Glycerol monostearate performs 3 functions in a plastic, and all 3 come from the same behaviour: the molecule is only partly compatible with the polymer, so it migrates out of the melt towards the surface. Compatibility is set by structure. Peter Greven states that polar esters such as GMS act internally, and the wider polarity rule recorded by Baerlocher puts polar moieties such as hydroxyl and ester groups on C14 to C18 chains in the internal class, while non-polar chains above C20 act externally.

The 3 functions of GMS in plastics are listed below.

• Antistatic agent: the surface layer binds atmospheric water, which drains static charge from polyethylene and polypropylene film and mouldings.
• Antifog and anti-drip agent: the same layer raises surface energy, so condensate spreads instead of beading on food packaging and greenhouse film.
• Internal lubricant: in PVC, the polar head keeps the ester compatible with the resin, lowering melt viscosity and torque without hazing a clear compound.

How does GMS work as an antistatic agent?#

GMS drains static charge by migrating to the film surface, where its 2 free hydroxyl groups bind atmospheric water into a thin conductive layer that carries charge away. The mechanism has 3 stages in sequence: the hydrophobic C18 tail anchors in the polymer, the hydrophilic glycerol head projects into the air, and ions dissolved in the adsorbed water film conduct charge laterally instead of letting it accumulate. GMS belongs to the migrating antistatic agents, the class that works only after it has reached the surface. How long does the film need before the effect appears?

Conditioning to a full surface monolayer takes about 2 days in LDPE and LLDPE according to Ampacet, so a bag tested straight off the line can fail a test it passes later in the week. Because the conducting medium is adsorbed water, performance tracks relative humidity: the ESD Association reports that a polybag lifted from a bench charges to 20,000 V at 10 to 25 % relative humidity but only to 1,200 V at 65 to 90 %. Untreated polyethylene and polypropylene sit at a surface resistivity of 10^15 to 10^16 ohm, and Ampacet places the plastics antistatic band at 10^9 to 10^13 ohm.

How does GMS work as an antifog and anti-drip agent?#

GMS clears fog by raising the surface energy of the film so that condensed water no longer beads: the droplets merge into a continuous transparent layer that runs off instead of scattering light. Water has a surface energy of 0.072 J/m2 and polyolefins are non-polar with a much lower surface energy, which is the reason condensate forms discrete droplets on untreated film. In an LLDPE greenhouse film, Zha, Zhang, Liang and colleagues at Hebei University of Technology measured a water contact angle of 38 degrees after GMS addition (ACS Omega, 2024). The full class of antifog additives is compared there by migration speed, film type and fog temperature.

Anti-drip is the same physics under a different name and a longer time scale. Condensate washes the ester layer off as it runs down the film, further GMS migrates out of the reservoir to replace it, and the film keeps working until the reservoir is depleted, which is why an antifog film has a service life rather than a permanent property.

How does GMS work as an internal lubricant in PVC?#

GMS acts as an internal lubricant in PVC because its polar glycerol head keeps it compatible with the resin, so it lowers melt viscosity and torque from inside the melt rather than forming a slip layer against the metal. Internal and external lubrication are separated by functional group and chain length in the Baerlocher scheme, and a C18 chain carrying hydroxyl and ester groups falls on the internal side. Peter Greven states the same rule from the other side, that lower polarity gives external effects.

Internal lubricants reduce torque and melt viscosity, barely influence fusion time and do not haze the compound at normal dosage, which is why a partial glycerol ester is the standard internal choice in clear rigid PVC while a paraffin wax is not. The internal and external balance of lubricants for PVC compounding decides how much GMS a recipe can carry before the melt slips instead of shearing.

What Are the Physical and Chemical Properties of GMS?#

GMS is a white to pale yellow waxy solid that melts between 54 and 65 °C (129.2 and 149 °F) depending on grade, with a molecular weight of 358.6 g/mol and a density of about 0.97 g/cm3 at 25 °C (77 °F). The verified property set is listed below, each melting figure tagged to its grade.

Solubility is the property that explains the rest. GMS is a non-ionic surfactant with limited solubility in water and in a non-polar polymer, and neither figure is published in the sources we verify, so this page states the behaviour rather than a number: the ester dissolves in the melt during compounding, exceeds its solubility limit as the part cools, and leaves the bulk slowly for the surface.

Which Polymers Use GMS, and at What Dosage?#

GMS is dosed at 0.05 to 0.6 % (w/w) in polyolefins and at 0.5 to 1.5 phr in PVC, with the antifog levels at the top of the polyolefin range and the antistatic and lubricant levels at the bottom. Why are PVC figures given in phr and polyolefin figures in percent? PVC recipes are built on 100 parts of resin, so every other ingredient is expressed against that base, and the conversion is wt% = phr of the ingredient divided by the total phr of the formulation, multiplied by 100.

The dosage table below separates the levels by function, because a Struktol lubricant figure and a Palsgaard antifog figure are not points on one range.

Ampacet reports that crystallinity in HDPE and PP homopolymer slows migration, and that polar resins, among them EVA, EMA, ionomers, polyamide and PET, retain antistats in the bulk and need higher levels than LDPE for the same surface effect. PVC recipes state GMS in PHR (parts per hundred resin), which converts to weight percent only once the full formulation total is known.

GMS in polyethylene film and mouldings#

Polyethylene takes GMS at 0.15 % (w/w) in LDPE and 0.3 % (w/w) in HDPE for lubrication and antistatic effect, and at 0.2 to 0.6 % (w/w) in film where the target is antifog. The split between the two polyethylene grades is a migration story: Ampacet reports that crystallinity in HDPE slows the ester's route to the surface, which is why the HDPE figure is twice the LDPE figure for the same nominal job. In injection-moulded parts, written moldings in US supplier literature, the same levels apply.

Blends are common in HDPE for the same reason. Ampacet reports that ethoxylated amines perform best in HDPE and diethanolamides best in LDPE and LLDPE, so GMS in an HDPE compound is usually one half of an antistat package. GMS sits in the standard film package next to slip, antiblock and processing aids described under additives for polyethylene.

GMS in polypropylene#

Polypropylene uses GMS at 0.05 to 0.5 % (w/w), the widest range of any polymer in the Struktol data, because crystallinity governs how fast the ester reaches the surface. Homopolymer PP is the slow end of that range and random copolymer the fast end, and supplier dosage tables from Palsgaard show PP needing roughly 3 to 5 times the antifog loading of polyethylene, with homopolymer needing more than random copolymer for the same result.

That loading penalty is why PP antifog film usually goes to a different chemistry: polyglycerol esters hold the antifog effect longer in PP film and are dosed at 1.0 to 2.0 % (w/w) in the Palsgaard range. Crystallinity, nucleation and the rest of the PP package are covered under additives for polypropylene.

GMS in rigid and flexible PVC#

Rigid PVC compounds take 0.5 to 1.5 phr of GMS and flexible PVC compounds 0.5 to 1.0 phr, dosed as an internal lubricant that keeps clear formulations clear. Struktol quotes both figures against TR 151-40, and both sit inside a lubricant block that also carries an external partner such as a paraffin or oxidised polyethylene wax plus a metal soap.

Cling film is the flexible-PVC case where the second function takes over. Palsgaard specifies Einar 211 at 0.5 to 1.0 % (w/w) for cold fog and 0.3 to 0.6 % (w/w) for hot fog in PVC cling film, levels set by the fogging requirement rather than by the rheology. GMS is one line in the lubricant block of the recipes on additives for PVC.

What Is GMS Used For? 6 Applications in Plastics#

GMS is used in 6 plastics applications: antistatic packaging film, injection-moulded polyolefin parts, food packaging film, greenhouse and agricultural film, clear PVC, and additive masterbatch or colour concentrates. The 6 application areas are listed below in the order of the 3 functions, antistatic first, antifog second and lubricant third.

• Antistatic packaging film in LDPE, LLDPE and HDPE, for electronics, powders and dusty goods.
• Injection-moulded polypropylene and polyethylene parts, where the antistat also lubricates.
• Food packaging film with an antifog requirement, chilled (cold fog) and hot-filled (hot fog).
• Agricultural and greenhouse film, where the same chemistry is sold as a drip agent.
• Clear rigid and flexible PVC, where GMS is the internal lubricant.
• Additive masterbatch and colour concentrates, the form most converters buy.

Antistatic packaging film and ESD packaging#

GMS is the standard low-cost antistat in polyethylene packaging film, where the target is the dissipative band of ANSI/ESD S541: 1.0 x 10^4 to below 1.0 x 10^11 ohm surface resistance. ANSI/ESD S541 splits materials into the conductive, dissipative and insulative classes. Two further specifications set time-based criteria: NFPA 99 requires a static decay below 0.5 s to the 10 % cutoff at 50 % relative humidity or a surface resistivity below 10^11 ohm, and MIL-PRF-81705D requires a decay below 2.0 s to the 0 % cutoff at 12 % relative humidity together with a surface resistivity below 10^12 ohm.

Our verified sources hold no measured surface resistivity for a GMS-containing film, so no such value is stated here. The limiting factor is usually time rather than level, because GMS works for about 1 to 2 months. Resistance classes, bag constructions and the humidity question are set out on antistatic and ESD packaging.

Food packaging film and PVC cling film#

Food packaging film is the largest antifog use of GMS: Palsgaard specifies its sunflower-based Einar 211 grade at 0.3 to 0.6 % (w/w) in LDPE and LLDPE for cold fog and 0.2 to 0.4 % (w/w) for hot fog. Cold fog and hot fog are 2 different physical situations rather than 2 severities of one. Cold fog forms on a chilled display pack, where condensation is slow and the film must stay clear for days. Hot fog forms on a hot-filled or microwaved pack, where condensation is fast and hot, so the additive has to be at the surface within minutes.

PVC cling film carries higher numbers for the same 2 cases, 0.5 to 1.0 % (w/w) for cold fog and 0.3 to 0.6 % (w/w) for hot fog in the Palsgaard range. Both uses run under Regulation (EU) No 10/2011, where GMS is FCM substance 53 with no specific migration limit. The full film package for chilled and hot-fill packs is on additives for food packaging.

Greenhouse and agricultural film#

Greenhouse film uses GMS as an anti-drip agent, and it is the main ingredient of many commercial dripping agents on the market. The contact angle of 38 degrees measured by Zha and colleagues (ACS Omega, 2024) is the number behind that use.

Duration is the weak point, and the same 2024 study addressed it. In that work GMS adsorbed on alkali-treated diatomite reached an adsorption capacity of 218.4 mg/g, 32.08 % above untreated diatomite, and extended drip duration to 24 days against 15 days for the reference in an accelerated test at 60 °C (140 °F). The Chinese standard GB/T 4455-2019 requires more than 8 days in that accelerated dripping test at 60 °C (140 °F), and the authors equate 8 days at 60 °C with about 3 months in the field. Drip-agent selection and the accelerated 60 °C test are covered on antifog additives for greenhouse film.

Additive masterbatch and colour concentrates#

Most GMS reaching a converter arrives as additive masterbatch rather than as neat wax, because 0.15 % (w/w) of a waxy solid is hard to dose accurately on a film line. Slip, antiblock and antistatic additives are sold mainly in that form, and colour concentrates carry GMS as well. Let-down ratios are set per masterbatch rather than per substance: Mascom quotes 1 to 3 % let-down for an antifog masterbatch, which is not a GMS specification. GMS reaches most lines as additive masterbatch, dosed by let-down ratio rather than weighed neat.

How Well Does GMS Perform, and for How Long?#

The limit of GMS is time, not effect: its antistatic performance lasts about 1 to 2 months, because the ester crystallises on the surface and stops binding water. Ampacet records that service life for polyethylene and polypropylene film and mouldings. The surface layer is washed off by condensate and handling, more ester migrates out of the bulk to replace it, and the compound performs until the reservoir is depleted or until the surface layer has crystallised into a wax rather than an oriented monolayer.

How long does the antistatic effect of GMS last?#

A GMS-treated polyolefin film reaches its full antistatic effect about 2 days after extrusion and keeps it for about 1 to 2 months, after which the surface layer crystallises and the effect falls away. Both ends of that window come from migration speed. Palsgaard reports that shorter-chain glycerides migrate to the surface almost instantly while medium and longer-chain glycerides take days, and GMS with its C18 chain sits in the second group.

Loading cannot buy more time. The same solubility limit that drives the effect causes blooming and exudation in plastics when the loading is too high, so an over-dosed film gains a greasy surface instead of a longer service life. Where a longer life is required, the formulation changes chemistry rather than level.

How is the performance of GMS measured?#

Three measurements decide whether GMS is working: surface resistivity by ANSI/ESD STM11.11, static decay time under NFPA 99 or MIL-PRF-81705D, and water contact angle or drip duration for the antifog function. ANSI/ESD STM11.11 covers surface resistance and STM11.12 volume resistance, with IEC 61340-5-1 as the international equivalent for ESD-protected areas.

No measured surface resistivity, static decay time or coefficient of friction for a GMS-containing compound exists in our verified sources, so the table above states class limits and methods rather than a result for this substance. The measurement itself, including electrode geometry and conditioning, is described on surface resistivity, and the hot-fog and cold-fog protocols behind the antifog figures are compared on antifog testing.

How Does GMS Interact with Other Additives?#

GMS shares one surface with every other migrating additive in the formulation, so its performance depends on what else blooms: ethoxylated amines help it, antiblock silica and slip agents work against it. Competition at the interface is the common thread: every additive that leaves the bulk for the surface, and every process step that changes it, either clears the way for the ester layer or occupies the space it needs.

Synergy: GMS plus ethoxylated amines#

GMS and ethoxylated amines are combined because they act on different timescales: GMS gives the immediate antistatic effect and the amine sustains it, and Ampacet reports the pair as synergistic. The division of labour follows migration speed: the ester reaches the surface in about 2 days, and the amine holds the effect past the 1 to 2 months GMS alone delivers. That pairing is also the commercial mainstream: the 2 chemistries together account for more than 50 % of the antistatic additive market according to a 2023 review in Polymers.

Resin choice decides the ratio, because Ampacet reports amines performing best in HDPE and diethanolamides best in LDPE and LLDPE. The partner chemistry, ethoxylated amine, carries the long-term effect and a group specific migration limit that GMS does not have, which is the trade the next comparison section examines.

Antagonists: antiblock silica, slip agents and acidic additives#

Five formulation and process factors reduce the effect of GMS: antiblock silica, slip agents, corona treatment, lamination or polar layers, and tight winding. Ampacet documents each of them for migrating antistats. The 5 antagonists of a migrating antistat are listed below.

• Antiblock silica: the high-surface-area particles adsorb the antistat and remove it from the interface.
• Slip agents: erucamide and oleamide migrate to the same surface and compete for the space.
• Corona treatment: it accelerates migration to the treated side and drains the reservoir faster.
• Lamination and polar layers: polyamide and PET layers and laminating adhesives act as sinks.
• Tight winding: it slows diffusion in the roll, so conditioning takes longer than on free film.

Crystallinity in HDPE and PP homopolymer slows migration, and polar resins such as EVA, EMA, ionomers, polyamide and PET retain antistats and need higher loadings. Slip additives for plastic film compete with GMS for the same surface, so the 2 are balanced against each other rather than stacked.

What Is the Regulatory Status of GMS?#

GMS is registered under REACH, is not a Substance of Very High Concern, is authorised for EU food-contact plastics as FCM substance 53 without a specific migration limit, and is listed by the FDA as GRAS for direct food use under 21 CFR 184.1324 (status 24 September 2026). The matrix below states each instrument, the status and the reference, as checked for this page.

The REACH row explains why 2 registration entries exist for one purchase specification, and the food-contact rows explain why a GRAS number is not a packaging clearance. Registration, tonnage bands and dossier types are explained on REACH and plastic additives.

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

Yes, GMS is registered under REACH (Regulation (EC) No 1907/2006), and no, it is not a Substance of Very High Concern: ECHA CHEM held 25 active dossiers under EC 250-705-4 and no Candidate List entry when we checked on 22 September 2026. The commercial mixture carries its own registrations, 22 active dossiers under Glycerides, C16-18 mono- (CAS 91052-47-0), the entry a buyer of a technical grade is usually covered by.

No glycerol ester appears on the SVHC Candidate List in the version we checked, and GMS is on neither Annex XIV nor Annex XVII, and not on the POPs list of Regulation (EU) 2019/1021.

Is GMS allowed in food-contact plastics?#

Yes in the EU: GMS is listed in Annex I of Regulation (EU) No 10/2011 as FCM substance 53 (Ref 56585, glycerol esters with stearic acid) with no specific migration limit, so the generic 60 mg/kg limit and the 10 mg/dm2 overall migration limit apply. "No specific SML" is not "no limit", and the difference is the single most common misreading of an Annex I entry. Where no substance-specific value is assigned, the generic specific migration limit of 60 mg/kg applies to the substance and the overall migration limit of 10 mg/dm2 applies to everything the article releases, or 60 mg/kg for articles intended for infants and young children.

The United States answers across 2 routes rather than one Union list entry. FCM numbers, the generic SML and the overall migration limit are explained on EU 10/2011.

Is GMS FDA approved for plastic food packaging?#

GMS is GRAS as a direct food substance under 21 CFR 184.1324, but that is a food clearance, not a packaging clearance: 21 CFR 178.3130, the section covering antistatic and antifogging agents, lists amines, diethanolamides and alkyl sulfonates, not glycerol esters. The substances named in 178.3130 include N,N-bis(2-hydroxyethyl)alkyl(C12-C18)amine at up to 0.1 % in polyolefin food-contact film, a C13 to C15 amine, a tallow amine, lauric diethanolamide, a stearyl diethanolamide mixture and C10 to C18 alkyl sulfonate salts.

Which route applies to a given GMS grade in a given article, GRAS use under 184.1324, 21 CFR 178.3400 as an emulsifier and surface-active agent, or a supplier's own clearance, is confirmed on the supplier's letter of compliance. The difference between a GRAS listing and a packaging clearance is set out on FDA food contact rules.

Is GMS Safe? Health, Safety and Environmental Profile#

GMS carries no GHS hazard classification in the PubChem aggregate, is not on the REACH Candidate List and is listed by the FDA as generally recognised as safe for direct food use under 21 CFR 184.1324. Those are 3 status facts from 3 separate systems, and none is a toxicological conclusion drawn here. The 3 recorded positions are listed below.

• Classification: not classified under Regulation (EC) No 1272/2008 in the PubChem aggregate for CID 24699, which means no notified hazard class rather than an assessed absence of hazard.
• Food status: GRAS as glyceryl monostearate under 21 CFR 184.1324, and authorised for EU food-contact plastics as FCM substance 53 without a specific migration limit.
• Regulatory lists: not on the REACH Candidate List as of 22 September 2026, not on Annex XIV or Annex XVII, not listed under the POPs Regulation (EU) 2019/1021, and on the US TSCA inventory with Chemical Data Reporting submissions.

No LD50, NOAEL, acceptable daily intake or ecotoxicity value for GMS exists in the sources we verify, and none is stated here. A safety data sheet from the supplier remains the document of record for a specific grade, because a commercial GMS is a mixture whose classification is the supplier's own.

What Are the Alternatives to GMS?#

The 5 main alternatives to GMS are ethoxylated amines, lauric diethanolamide, glycerol monooleate, sorbitan monostearate and polyglycerol esters, with permanent antistatic polymers as the non-migrating option. The table below compares identity, function and regulatory position, and names the case in which each one beats GMS.

All 4 types of antistatic agents are compared side by side on the family hub, including the conductive-filler and ionic routes that sit outside this ester comparison.

GMS vs ethoxylated amines and diethanolamides#

GMS is the better choice when the effect is needed immediately and the food-contact file must stay simple, because it has no specific migration limit, while ethoxylated amines carry a group SML(T) of 1.2 mg/kg expressed as tertiary amine. Amines take over when the required service life exceeds the 1 to 2 months GMS delivers, and Ampacet reports amines performing best in HDPE and diethanolamides best in LDPE and LLDPE.

Compliance cost separates the 3 chemistries further. Lauric diethanolamide carries an SML of 5 mg/kg under FCM 923 plus a separate diethanolamine migration limit of 0.3 mg/kg, and in the United States it is cleared at 0.5 % in polyethylene containers and 0.2 % in polypropylene film of 30 µm or less. Chemistry adds one more constraint: amines and amides are basic and react with acidic additives and halogenated flame retardants, while the neutral GMS ester does not.

GMS vs glycerol monooleate, sorbitan monostearate and polyglycerol esters#

Within the antifog esters, the choice is a migration-speed decision: GMS sits between the faster-migrating glycerol monooleate and the slower, longer-lasting polyglycerol esters. Palsgaard states the underlying rule, that shorter-chain glycerides reach the surface almost instantly while medium and longer-chain glycerides take days. Glycerol monooleate is the unsaturated analogue, CAS 25496-72-4, C21H40O4, 356.5 g/mol, liquid at room temperature and therefore faster to the surface, listed as FCM 49 with no specific migration limit and GRAS under 21 CFR 184.1323.

Sorbitan monostearate, CAS 1338-41-6, C24H46O6, 430.6 g/mol, is the sorbitan-ester alternative, listed as FCM 415 and cleared under 21 CFR 172.842 and 21 CFR 178.3400, and it appears in greenhouse and drip applications where the requirement is duration rather than speed. Polyglycerol ester grades hold the antifog effect longest, which is why greenhouse film and PP film use them: they are listed as FCM 11, cleared under 21 CFR 172.854, and dosed at 1.0 to 2.0 % (w/w) in polypropylene film in the Palsgaard range.

GMS vs permanent antistats#

GMS depends on atmospheric humidity and lasts about 1 to 2 months, whereas a permanent antistatic polymer works at 12 % relative humidity as well as at 50 % and does not deplete. Humidity dependence is not a detail at the dry end of the range, where the ESD Association's 20,000 V polybag figure at 10 to 25 % relative humidity applies and the water the ester needs is least available.

The trade is loading and cost. Permanent antistatic additives work at 12 % relative humidity and do not deplete, at a much higher loading and a much higher price per part than 0.15 % (w/w) of a glycerol ester, which is why GMS keeps the volume in short-life packaging. Ampacet reports that inherently dissipative polymers show a surface resistivity at 12 % relative humidity similar to the value at 50 %.

Who Manufactures GMS? Grades and Suppliers#

GMS is produced by 7 suppliers covered in our substance directory, including Croda (Atmer 129), Nouryon (Armostat 801), Palsgaard (Einar 211), Struktol (TR 151-40 and TR 151-95), Baerlocher (Baerolub L-MS) and Peter Greven (LIGALUB 11 GE). Riken Vitamin is the seventh, with Dimodan among its glycerol ester grades. Grade differences matter more than producer differences here, because the monoglyceride content and the melting range decide how the material doses and how fast it migrates.

Buyers should ask for the monoglyceride content, the melting range and a letter of compliance for the intended food-contact use, because a GMS 40 and a high-monoglyceride grade carry the same CAS number and behave differently on the same line. More producers, plant locations and distribution partners are in the directory of antistatic additive manufacturers.

How Does GMS Fit into the Wider Group of Surface-Active Plastic Additives?#

GMS is the reference partial glycerol ester among the plastics lubricants, the group that sits beside the metal stearates, the waxes and the fatty amides as the surface-active additives of a compound. What unites that group is behaviour rather than chemistry: every member is only partly compatible with the polymer and ends up at an interface, either polymer-air or polymer-metal. GMS is the reference member of the ester lubricants, the group that also holds PETS, EGDS and the montan esters.

Ester lubricants beyond GMS: EGDS, PETS and stearyl stearate#

Ethylene glycol distearate (EGDS, CAS 627-83-8) is the glycol ester next to GMS: it has a dropping point of 63 to 73 °C (145.4 to 163.4 °F) and is used at 0.5 to 1.5 phr in rigid PVC window, siding and profile compounds. Its molecular formula is C38H74O4 at 595.0 g/mol under EC 211-014-3. The 3 further ester lubricants recorded beside GMS in our data set are listed below.

• Ethylene glycol distearate (EGDS), CAS 627-83-8, 595.0 g/mol: glycol diester, 0.5 to 1.5 phr in rigid PVC profile compounds.
• Pentaerythritol tetrastearate (PETS): the polyol ester of the group.
• Stearyl stearate, CAS 2778-96-3, C36H72O2, 537.0 g/mol: the wax ester of the group.

The montan esters and the complex esters complete the class beside ethylene glycol distearate.

Non-plastics uses of glycerol monostearate#

Most search results for glycerol monostearate describe its use as a food emulsifier and as a cosmetic thickener, which are regulated under different rules and are outside the scope of this reference. The food status still matters to a plastics buyer for one reason: the GRAS listing under 21 CFR 184.1324 is what suppliers cite when a GMS grade goes into food-contact film, and it is the reason the US compliance conversation starts with a food regulation rather than a packaging one. No dosage, benefit or use level for those applications is given here.

Is glycerol monostearate the same as E471?#

The E471 designation is not established in the sources we verify, so this page does not confirm it. What is established for the plastics identity of the substance is CAS 31566-31-1, EC 250-705-4 and FCM substance 53 under Regulation (EU) No 10/2011, and EU food-additive numbering sits under a different instrument and outside the scope of this reference.

Does GMS make the plastic surface greasy?#

Over-dosing does: an antifog or antistat loading above the recommended range produces a greasy bloom on the surface and loses the effect instead of extending it. Loading above the solubility limit is the standard cause of surface defects described under additive migration in plastics, and for GMS the visible form is a waxy film that no longer binds water because it has crystallised rather than oriented.

Is GMS made from vegetable oil?#

Grades differ: Palsgaard describes its Einar 211 as a sunflower-based GMS, and the commercial material is registered under REACH as Glycerides, C16-18 mono-, which points to a C16 to C18 fatty acid feedstock. No feedstock statement for any other grade exists in the sources we verify, and no vegan, halal, kosher or bio-based certification claim is made here for any grade.