Lubricants for PVC Compounding: Internal and External Balance, 6 Classes and Dosage in phr

Lubricants for PVC compounding are waxes, metal soaps, esters, fatty acids and amides added at roughly 1 to 3 phr to cut the friction between PVC particles and between the melt and hot metal, so the compound fuses at the right point in the machine instead of degrading. Rigid PVC has a high melt viscosity and a narrow window between fusion and thermal degradation, so the question is never whether to lubricate but how to balance internal against external action. This reference covers only lubricants compounded into PVC, not the gasket and thread lubricants plumbers apply to join finished pipe, a separate product class covered in the scope note near the end of the page.

Lubricants make up a small share by weight of all plastic additives consumed, yet no rigid PVC compound runs without them. This page sets out the internal and external classification, the 6 chemical classes, the phr package per process, how fusion is measured, what over- and under-lubrication look like, and which lubricants are listed for food and drinking-water contact.

Key figures

• 6 chemical classes of lubricant are used in rigid PVC: metal soaps, hydrocarbon waxes, oxidized and montan waxes, fatty acid esters, fatty acids and hydroxy fatty acids, and fatty amides.
• The classic rigid pipe package runs 0.6 to 1.5 phr paraffin wax, 0.6 to 1.5 phr calcium stearate and 0.1 to 0.2 phr oxidized PE wax.
• 0.07 to 0.2 phr is the working range of oxidized PE wax, the strongest metal-release lubricant per phr in the PVC toolbox.
• 1 to 10 phr is the dosage band PVC lubricants share with heat stabilizers and impact modifiers.

Why Does PVC Need Lubricants?#

PVC needs lubricants because its melt viscosity is high and the gap between the temperature at which it fuses and the temperature at which it releases hydrogen chloride is narrow, so friction heat alone can push a compound into degradation. Slow elimination of hydrogen chloride starts at 100 to 120 °C and rapid thermal degradation sets in near 250 °C, a window the lubricant package has to manage together with the heat stabilizer. Inside it, PVC resin grains break apart into primary particles and then fuse into a continuous melt, a sequence called gelation, and the lubricant package decides how fast that runs and how much shear heat it generates. The hub on processing lubricants for plastics covers the same 6 classes in polyolefins, styrenics and engineering plastics, whose melts are less viscous than PVC.

What does a lubricant do during PVC dry blending, fusion and extrusion?#

A lubricant works in two places in a PVC line: between the resin particles and polymer chains inside the melt, and at the interface between the melt and the hot steel of the screw, die or calender roll. The particles first come together during dry blending, a hot and cold mixing step with a defined order of addition, and PVC dry blending fixes where each lubricant enters the mix before grains break into primary particles under shear and heat.

The lubricant package sets 5 properties of a rigid PVC compound, and every later formulation decision in this article traces back to one of them.

• Fusion time and torque, because external lubricants prolong fusion while internal lubricants shorten it.
• Melt viscosity, which internal lubricants reduce by lowering chain-to-chain friction.
• Metal release, which external lubricants govern at the melt-metal interface.
• Clarity, gloss and plate-out, which shift with the polarity of the lubricant blend.
• Printability and weldability, which external lubricants can reduce if they migrate to the surface.

What is the difference between internal and external lubricants in PVC?#

Internal lubricants reduce the friction between PVC chains and lower melt viscosity, while external lubricants reduce the adhesion between the PVC melt and hot metal and prolong fusion; a lubricant that does both is called a combined lubricant. Baerlocher classifies internal lubricants as polar and PVC-compatible, keeping transparency and not exuding, and external lubricants as mostly non-polar, prone to haze and exudation once overdosed, a condition compounders call over-lubrication.

Table 1. Internal versus external lubricant performance (Baerlocher classification, 2017)

Polarity and chain length decide which side of the matrix a molecule falls on: polar groups (hydroxyl, carboxylate, calcium carboxylate) on chains of C14 to C18 act internally, while non-polar chains above C20 and up to about C100 act externally, a rule Baerlocher states for its product range. Peter Greven adds that reducing the polarity of an ester moves it toward external action, and the table below spans that same gradient across 14 named lubricant types in the Baerlocher range.

Table 2. Melting and dropping points across the polarity gradient (Baerlocher product range, °C)

Melting and dropping points are supplier values for the named grades, not substance constants; trials on the running line decide the final level.

Are PVC lubricants the same as plasticizers, processing aids or heat stabilizers?#

No: a lubricant changes friction, a plasticizer changes the bulk softness of the compound, an acrylic processing aid raises melt strength and speeds fusion, and a heat stabilizer neutralises the hydrogen chloride PVC releases. A heat stabilizer scavenges hydrogen chloride rather than changing friction, so it is dosed separately even though the two interact, and a plasticizer changes bulk phase, not surface behaviour: flexible PVC carries 5 to 65 wt% plasticizer, an order of magnitude more than any lubricant level. An acrylic processing aid does the opposite job of an external lubricant, entangling with PVC chains to raise mixing torque and counteract the fusion delay an external lubricant introduces, an effect Sombatsompop and Phromchirasuk documented in 2004 in the Journal of Applied Polymer Science.

What Are the 6 Classes of PVC Lubricants?#

The 6 classes of PVC lubricant are metal soaps, hydrocarbon waxes, oxidized and montan waxes, fatty acid esters, fatty acids and hydroxy fatty acids, and fatty amides, and the first three make up the classic rigid PVC package. This order runs by prominence in a rigid compound, not alphabetically, and every later list, table and schema entry repeats it, matching how the Baerlocher and Struktol product ranges group their own grades.

Table 3. The 6 classes of PVC lubricant

1. Metal soaps: calcium stearate and zinc stearate#

Metal soaps are the calcium and zinc salts of stearic acid, the only lubricant class in PVC that also takes part in heat stabilization: calcium stearate acts largely internally and buffers the compound, while zinc stearate acts externally and substitutes the labile chlorine atoms that start dehydrochlorination. Grades and production routes for the wider family of metal stearates sit on the metal-stearate page.

Calcium stearate carries CAS 1592-23-0, EC 216-472-8, molecular weight 607.0 g/mol; it melts at 179 °C pure (PubChem), 140 to 165 °C commercial (Struktol) and about 160 °C in the Baerlocher range, with calcium content of 6.3 to 7.9 % by grade. Baerlocher classes it internal, but it also functions as a Ca/Zn co-stabilizer and, in polyolefins, an acid scavenger, and it is the single most used lubricant in rigid PVC.

Zinc stearate carries CAS 557-05-1, EC 209-151-9, molecular weight 632.3 g/mol, melting at 130 °C (PubChem) and about 120 °C (Baerlocher). Baerlocher classes it external; in PVC it substitutes labile chlorine, so the zinc chloride that forms has to be taken up by the calcium soap, a mechanism the fusion section below explains in full.

Metal soaps are produced by precipitation, direct conversion, the melt process or the continuous COAD process; a calcium/zinc preblend melts at about 100 °C against 120 to 130 °C for the single soaps (Peter Greven). Calcium stearate rarely appears in a rigid PVC package without a matching zinc soap alongside it.

2. Hydrocarbon waxes: paraffin, PE wax and Fischer-Tropsch wax#

Hydrocarbon waxes are non-polar alkanes that sit between the PVC melt and the steel, which makes them the reference external lubricants: paraffin at roughly 200 to 1,000 g/mol, PE wax averaging up to about 10,000 g/mol, and Fischer-Tropsch wax with a narrow distribution in the paraffin range. None of the three carries the polar groups that let a lubricant wet PVC, so all three migrate to the metal interface instead, and all four wax chemistries used across plastics, including the montan wax covered below, are compared by molecular weight on polymer waxes, the hub for the class.

Paraffin wax, CAS 8002-74-2, EC 232-315-6, melts at 54 to 56 °C (Baerlocher L-KM) with a dropping point of 67 to 72 °C and specific gravity 0.92 (Struktol PE(H)-165, fully refined); it carries 100 active REACH registrations and is the reference external lubricant of the PVC pipe industry. PE wax, CAS 9002-88-4, has a broad molecular weight distribution melting at 90 to 105 °C (Struktol PE(H)-100) and 102 to 110 °C (Baerlocher PA-L); as a polymer rather than a discrete substance it is exempt from REACH registration, unlike paraffin.

Fischer-Tropsch wax, a narrow-distribution synthetic paraffin in the same 200 to 1,000 g/mol range, is produced mainly by Sasol and melts at 100 to 105 °C in the Baerlocher synthetic-paraffin grade; Mhlabeni, Jamiru and Mhike reported in 2024 in Frontiers in Chemical Engineering that lower-molecular-weight waxes tend to exacerbate die drool, the melt build-up on the open faces of the extrusion die.

3. Oxidized and montan waxes: the strongest metal-release lubricants#

Oxidizing a polyethylene wax adds carboxyl and carbonyl groups that anchor to hot steel, which is why oxidized PE wax gives more metal release per phr than any other lubricant in PVC and is dosed at only 0.07 to 0.3 phr. Oxidized polyethylene wax carries CAS 68441-17-8 and EC 614-498-8; Struktol PE(O)-300 has a dropping point of 131 °C and viscosity of 6,000 to 14,000 cps at 150 °C, PE(O)-600 drops at 99 to 108 °C at 320 to 400 cps, and working levels run 0.1 to 0.2 phr in pipe and profile, 0.07 to 0.15 phr in opaque injection moulding and calendering, and 0.1 to 0.3 phr in clear extrusion, scaling with the metal surface area a compound has to release from.

Montan wax, CAS 8002-53-7, EC 232-313-5, is a lignite extract of 62 to 68 % long-chain esters, 22 to 26 % acids and 7 to 15 % alcohols and hydrocarbons, melting at 82 to 95 °C crude; its refined derivatives are made by Gersthofen oxidative refining to montanic acids, then partial esterification with ethylene glycol or 1,3-butanediol. Montan wax stays an unlinked mention here; its link sits later, in the food-contact section, where the heading matches the FDA rule written for its ester grades.

4. Fatty acid esters: GMS, EGDS, complex and montan esters#

Fatty acid esters are the tuning class of PVC lubrication, and their polarity decides whether they act internally or externally: a polar partial ester such as glycerol monostearate acts internally and keeps a compound clear, while a less polar complex ester or montan ester shifts toward external action and metal release. The full range of ester lubricants, from GMS and EGDS to PETS and the complex and montan esters, is compared by polarity on the dedicated ester page.

Glycerol monostearate carries CAS 31566-31-1 (also listed as 123-94-4), a molecular weight of 358.6 g/mol, and a melting point of 58 to 60 °C for a 40 to 45 % monoglyceride grade such as Struktol TR 151-40, dosed at 0.5 to 1.5 phr in rigid PVC and 0.5 to 1.0 phr in flexible PVC. Ethylene glycol distearate, CAS 627-83-8, EC 211-014-3, molecular weight 595.0 g/mol, has a dropping point of 63 to 73 °C and is used at 0.5 to 1.5 phr as a combined lubricant in window, siding and profile compounds.

Complex esters run at 0.3 to 0.75 phr alongside a hydroxyl glycerol ester at 0.7 to 1.5 phr in calendering and injection moulding, and a complex ester paired with a calcium soap melts at 125 to 135 °C against 50 to 54 °C for a plain glycerol ester. Glycerol monostearate also works as an antistat and antifog additive in polyolefins; the proprietary "complex ester" grades (Struktol V-PEAS, VLB-602) carry no stated chemical identity beyond their polarity class.

5. Fatty acids and hydroxy fatty acids#

Stearic acid is both an external lubricant in its own right and the raw material of the other classes, because the metal soaps, the glycerol and glycol esters and the bis-amides are all made from it. It carries CAS 57-11-4, EC 200-313-4 and a molecular weight of 284.5 g/mol, melting at 69.3 °C for the pure acid and 54 to 64 °C for commercial lubricant grades such as Baerlocher FTA and Peter Greven LIGALUB SH. One supplier source gives a rigid PVC dosage of 0.1 to 0.8 phr, unconfirmed against an independent data sheet; the more reliable role of stearic acid in plastics is as feedstock for the metal soaps, esters and amides covered above.

12-hydroxystearic acid, CAS 106-14-9, is an external lubricant and the precursor of calcium 12-hydroxystearate; hydroxy fatty acids melt at 70 to 80 °C across the Baerlocher range, roughly 15 °C above the unsubstituted fatty acids.

6. Fatty amides: ethylene bis stearamide#

Ethylene bis stearamide is the highest-melting lubricant in normal PVC use, at 138 to 146 °C, which keeps it solid through most of the dry-blend stage and makes it act at the melt-metal and particle interfaces rather than inside the melt. It carries CAS 110-30-5, EC 203-755-6 and a molecular weight of 593.0 g/mol, melting at 135 to 146 °C by PubChem and 138 to 144 °C in the Baerlocher range (Baerolub L-AK). Baerlocher classes it as external, while Struktol positions the same chemistry as internal and external for rigid moulding and extrusion; our source library holds no PVC-specific phr figure for it, so this page states the blend level rather than inventing one.

Ethylene bis stearamide (EBS) is also the reference dispersant for ABS and colour concentrates, and EBS-replacement blends are used at 0.5 to 2.0 % across ABS, PVC and PS, a range describing the blend rather than the neat substance dosed alone in PVC.

How Do Internal and External Lubricants Change PVC Fusion?#

Lubricants change PVC fusion by controlling how fast resin grains break down into primary particles: external lubricants keep the particles apart and delay fusion, while internal lubricants lower melt viscosity once fusion has started. Krzewki and Collins established this picture in 1981 in the Journal of Macromolecular Science B: paraffin wax delays the breakdown of resin particles and therefore fusion, calcium stearate can either accelerate or delay fusion depending on temperature and on whether wax is present, and with wax present, more calcium stearate accelerates fusion rather than slowing it.

Why the internal / external labels do not predict performance#

Calcium stearate is classed as an internal lubricant and paraffin as an external one, yet Rabinovitch, Lacatus and Summers showed at BFGoodrich in 1984, in the Journal of Vinyl Technology, that it is the polar calcium stearate which wets the hot metal, while the non-polar paraffin fluidizes the layer that calcium stearate has formed. Their differential thermal analysis, haze, microscopy, metal-release and Brabender fusion data together concluded that the common internal/external classification is deficient in explaining performance, because lubrication between PVC primary particles follows the same physics as lubrication at the metal wall rather than a separate mechanism.

Formulators therefore read a lubricant by its polarity and chain length and confirm the reading on a torque curve, instead of trusting the label alone. Baerlocher's own counter-intuitive pairing, calcium stearate internal and zinc stearate external, still works in practice: the classification is a starting point for selection, not a guarantee of behaviour once mixed with waxes, esters and a stabilizer one-pack.

How is PVC fusion measured?#

PVC fusion is measured in a torque rheometer: a weighed dry blend is charged into a heated mixing head, and the torque trace shows when the grains break down, how much work the melt takes, and how long it stays stable before it degrades. The practice runs on Brabender-type torque rheometry rather than a single fixed pass/fail number, and charge weight, rotor speed and temperature for PVC fusion testing by torque rheometer sit on the dedicated method page. Our source library holds no universal numeric fusion-time target for PVC; the end point is set by the individual compound specification, not by one industry threshold.

A torque curve gives 4 numbers that decide whether a lubricant package is balanced.

• Fusion time, the point at which torque peaks as particles break down.
• Fusion torque, the peak work the melt takes during breakdown.
• Equilibrium torque, the steady value once the melt has fully fused.
• Stability time, how long the equilibrium torque holds before it rises again as the compound degrades.

Heat stability itself is measured separately, by the Congo red discoloration method to ISO 182-1 at 180 °C, since a stable torque trace does not by itself confirm that the stabilizer package is adequate.

How Much Lubricant Does Rigid PVC Need? Dosage in phr#

A rigid PVC compound normally carries between 1 and 3 phr of total lubricant, split between external and internal action by process: pipe and profile extrusion run on paraffin plus calcium stearate plus oxidized PE wax, while calendering, injection moulding and clear compounds move to ester systems. Phr means parts per hundred parts of resin by weight; weight percent is the phr of one ingredient divided by the sum of all phr, times 100.

In the Plastics Pipe Institute's published TR-2-2023 range composition for PVC 1120 pressure pipe, cell class 12454, the lubricants are 0.45 phr calcium stearate, 1.20 phr paraffin wax and 0.15 phr PE wax on a total of 108.03 phr, so the package works out to 1.80 phr, or 1.67 wt%, a calculation from a published range composition rather than a supplier recipe. Any package converts the same way with the PHR to weight percent calculator.

Table 4. Master phr package by process (Struktol technical data sheets)

Supplier TDS ranges for named grades. Struktol notes on several sheets that calcium stearate should be reduced as far as possible for better flow, and that paraffin is not recommended for articles that are to be printed. Trials on the running line decide the final level.

Table 5. US PVC pressure pipe range composition (PPI TR-2-2023, PVC 1120, cell class 12454)

Request quotes for PVC lubricants by grade or CAS number, process, volume and country through the plastic additive supplier finder, and download the PVC Lubricant Package Selector (phr) for pipe, profile, calendering, injection moulding and clear compounds.

Rigid PVC pipe extrusion: paraffin, calcium stearate and PE wax#

Rigid PVC pipe runs on the oldest and simplest package in the industry: 0.6 to 1.5 phr paraffin wax, 0.6 to 1.5 phr calcium stearate and 0.1 to 0.2 phr oxidized PE wax, a combination that both Struktol and the Plastics Pipe Institute range composition describe within the same limits. The PPI TR-2-2023 range composition allows calcium stearate 0.4 to 1.5, paraffin 0.6 to 1.5 and PE wax 0.0 to 0.3 phr, so the two sources agree closely on paraffin and differ only in whether the third component is stated as plain PE wax or oxidized PE wax. Up to 0.3 phr polyethylene wax sits inside the same pipe range composition as a lower-cost alternative to oxidized PE wax where less metal release is needed.

PVC window profile and siding extrusion#

Window profile and siding compounds use the same three components as pipe but at a tighter ratio, 0.8 to 1.2 phr paraffin with 0.8 to 1.2 phr calcium stearate and 0.1 to 0.2 phr oxidized PE wax, because the profile die demands a longer, more uniform fusion. Ethylene glycol distearate at 0.5 to 1.5 phr is offered as an alternative combined-lubricant route for the same window, siding and profile compounds, replacing the three-component package with a single ester.

Rigid PVC injection moulding#

Rigid PVC injection moulding (also spelled injection molding) replaces the paraffin of extrusion with an ester system, typically 0.7 to 1.5 phr of a hydroxyl glycerol ester with 0.3 to 0.75 phr of a complex ester, because the mould has to release cleanly in seconds rather than over a metre of die land. Opaque mouldings add 0.07 to 0.15 phr oxidized PE wax and 0.3 to 1.0 phr calcium stearate for metal release, while the clear route drops both the wax and the metal soap to protect transparency.

Rigid PVC calendering and sheet: complex esters and zinc stearate#

Calendered rigid PVC sheet needs release on four hot rolls in sequence, so the package pairs 0.7 to 1.5 phr of a hydroxyl glycerol ester with 0.5 to 0.75 phr of a complex ester, 0.3 to 0.75 phr calcium stearate and only 0.07 to 0.15 phr oxidized PE wax. Zinc stearate spreads evenly through the roll nip because it melts at about 120 °C in the Baerlocher range, low enough to soften early in the calendering pass without staying liquid long enough to bloom to the surface.

Clear and transparent rigid PVC#

Clear rigid PVC is where the internal / external balance is most visible: an over-dosed external lubricant produces haze and exudation, so transparent compounds run on polar esters at 0.7 to 1.0 phr plus 0.3 to 0.6 phr of a complex ester and no metal soap in the quoted package. Clear extrusion instead relies on oxidized PE wax alone at 0.1 to 0.3 phr, because its low dosage and high polarity give metal release without the haze that a heavier external wax would cause.

Flexible PVC and plastisol#

Flexible PVC needs far less lubricant than rigid PVC because the 5 to 65 wt% of plasticizer already lowers melt viscosity, which leaves the lubricant to handle release: 0.5 to 1.0 phr glycerol monostearate is a typical level. Liquid glyceryl mono- and dioleate esters serve the same role in plastisol formulations, where the lubricant has to disperse into a liquid paste rather than a dry powder blend.

Wood-filled PVC and other highly filled compounds#

Wood-filled PVC needs 2 to 8 parts of a blended lubricant, several times the unfilled level, because wood flour multiplies the internal surface area that has to be wetted before the melt can move. Wood-filled polyolefin compounds follow the same logic at 1 to 6 % of the compound weight, and blend compositions and dosing rules for lubricants for wood-plastic composites cover both wood-PVC and wood-polyolefin systems in full.

How Do Lubricants Interact with the Rest of the PVC Formulation?#

A PVC lubricant is never chosen on its own: calcium and zinc stearate are simultaneously lubricants and parts of the Ca/Zn stabilizer system, the acrylic processing aid pulls fusion forward while the external lubricant pushes it back, and fillers and pigments absorb lubricant that the formulator then has to add back. Most European rigid PVC compounders buy a stabilizer and lubricant one-pack, tuned per application, so in practice the lubricant decision is often made inside the one-pack rather than component by component (Baerlocher).

Table 6. Co-additive effects on the lubricant balance

Zinc stearate is a lubricant and a Ca/Zn co-stabilizer at once, and the zinc chloride it forms as it substitutes labile chlorine has to be taken up by the calcium soap; when the calcium soap cannot keep pace, the excess zinc and zinc chloride cause a discoloration fault called zinc burning, corrected with more calcium soap plus co-stabilizers such as polyols and beta-diketones rather than by removing zinc stearate. The same metal soaps also work as acid scavengers at 0.05 to 0.20 % in polyolefins, an order of magnitude below the PVC lubricant range because that role is catalytic rather than interfacial.

What Goes Wrong: Over-Lubrication, Under-Lubrication and Plate-Out#

Both faults are visible on the machine before they are visible in the laboratory: too much external lubricant delays fusion, leaves the melt under-gelled and deposits material on the die, while too little lets friction heat build until the compound discolours. Over-lubrication shows itself in 5 ways.

• Haze in a clear compound, from an overdosed external lubricant clouding the polar ester matrix.
• Surface exudation or bloom, where the excess lubricant migrates out of the melt after cooling.
• Long fusion and an under-gelled melt, because the external lubricant keeps particles apart too long.
• Poor print, weld or bond quality, as migrating external lubricant coats the surface.
• Plate-out on the die, screw or calender rolls, a white deposit built from lubricant, pigment fines and metal-soap reaction products.

Under-lubrication shows itself in 4 ways.

• Discoloration, as friction heat outruns the stabilizer's capacity.
• Rising torque, since the melt cannot flow past the resin surfaces.
• Excessive shear heat, which accelerates degradation locally.
• Black specks after a long run, from degraded material trapped in dead zones of the screw or die.

Plate-out in PVC processing comes from over-lubrication, an incompatible external lubricant, metal-soap reaction products, and pigment or filler fines together, and it is corrected by rebalancing the lubricants, moving to a low-plate-out stabilizer one-pack, or adding an acrylic processing aid. Our source library holds no numeric threshold for how much plate-out counts as a fault; every compounder sets that limit against the appearance of their own die and calender surfaces.

Table 7. Fault, likely cause and fix

Which PVC Lubricants Are Allowed in Food-Contact and Drinking-Water PVC?#

In the EU, food-contact PVC may contain only lubricants listed in Annex I of Regulation (EU) No 10/2011, or covered as salts and esters of an authorised acid, bound by the overall migration limit of 10 mg/dm² unless a specific limit applies. In the United States, PVC lubricants are cleared section by section under Title 21 of the Code of Federal Regulations rather than through one positive list, and calcium, zinc and magnesium stearate all carry generally-recognised-as-safe status as food substances. Drinking-water contact in the EU runs through the positive lists under Directive (EU) 2020/2184, and the implementing decision covering PVC pipe applies from 31 December 2026; our source library holds no lubricant-specific entry numbers for that list, so this page states only the instrument and the date. Plastic additives in drinking-water contact, including the same metal stearates and waxes, are covered in full on the drinking-water regulation page.

EU 10/2011: FCM numbers and SMLs for PVC lubricants#

The EU treats most PVC lubricants as salts or esters of stearic acid, FCM No 106, rather than as individually listed additives, which is why calcium stearate carries no specific migration limit while zinc stearate is capped at 5 mg/kg through the Annex II limit for zinc that has applied since Regulation (EU) 2020/1245.

Table 8. Food-contact matrix for PVC lubricants

Where no specific migration limit is listed, the generic SML of 60 mg/kg and the overall migration limit of 10 mg/dm² of Regulation (EU) No 10/2011 apply. US clearances are conditions of use, not recommended dosages.

How FCM numbers, specific migration limits and the overall migration limit work together is explained in full on the EU 10/2011 regulation page.

United States: 21 CFR 178.3770, 177.1620 and the GRAS stearates#

The United States clears PVC lubricants section by section rather than through one positive list: montan ester lubricants for PVC have their own rule at 21 CFR 178.3770, oxidized polyethylene runs under 177.1620, and the metal stearates are generally recognised as safe as food substances. The structure of the US sections, and how a GRAS listing differs from a food-contact clearance for a finished article, is decoded in full on FDA food contact rules for plastic additives (21 CFR).

21 CFR 178.3770 clears the partial esters of oxidatively refined, Gersthofen-process montan wax acids with ethylene glycol or 1,3-butanediol, with or without calcium neutralisation, specifically as lubricants for PVC food-contact articles, at a dropping point of 76 to 105 °C to ASTM D566. 21 CFR 177.1620 covers oxidized polyethylene of number-average molecular weight at least 1,200, and 172.260 covers it as a direct food additive; calcium stearate is GRAS under 184.1229 and prior-sanctioned under 181.29, zinc stearate GRAS under 182.8994, magnesium stearate under 184.1440 and stearic acid under 184.1090. A GRAS listing as a food substance is not a food-contact clearance for the finished PVC article, and this page never writes "FDA approved".

Who Supplies PVC Lubricants?#

PVC lubricants come from a small set of specialists: Baerlocher, Peter Greven and Struktol cover the full package from metal soap to wax to ester, while Clariant, PMC Biogenix, Valtris, Fine Organics, Sasol and Solstice Advanced Materials supply single classes. Buyers should compare grades by CAS number, dropping point and food-contact route, not by brand name, because the same chemistry is frequently sold under several trade names.

Table 9. Suppliers and brand lines

Baerlocher, of Unterschleissheim near Munich, has been family-owned for more than 200 years and employs about 1,150 people, selling BAEROLUB lubricants, CEASIT calcium stearates, ZINCUM zinc stearates and BAEROPAN one-packs. Plants and grades by company sit in the directory of calcium and zinc stearate manufacturers, and wax grades by producer sit under the PE wax and polymer wax manufacturers directory, covering Clariant, Sasol and Solstice Advanced Materials. Solstice Advanced Materials took over the A-C performance-additives brand when Honeywell Advanced Materials was spun off in 2025.

Send one request to several lubricant suppliers with the plastic additive supplier finder, specifying grade or CAS number, process, volume and country.

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What Else Does a Rigid PVC Compound Contain?#

Lubricants are one of eight or nine additive families in a rigid PVC compound, next to the heat stabilizer, the acrylic processing aid, the impact modifier, the filler, the pigment and, in flexible grades, the plasticizer. Global PVC production runs at about 40 Mt a year, the EU split is roughly 60 % rigid and 40 % flexible, and about 70 % of EU PVC goes into building and construction, according to the VinylPlus 2023 progress report; every one of those applications carries its own version of the same lubricant decision described on additives for PVC, the complete formulation guide for the polymer.

Heat stabilizers, one-packs and co-stabilizers#

Most rigid PVC compounds buy their lubricants inside a stabilizer one-pack, so the formulator adjusts a single product rather than four separate powders. The US pressure-pipe range composition shown earlier carries 0.3 to 1.0 phr of a tin stabilizer, and PVC heat stabilizers sets out the calcium/zinc, organotin, barium/zinc and legacy lead systems that these one-packs are built on, while PVC co-stabilizers covers the polyols and beta-diketones used to correct zinc burning.

Rigid versus flexible PVC lubrication#

Rigid PVC needs the full internal and external package, while flexible PVC leaves most of the internal work to the plasticizer and uses lubricant mainly for release. Complete recipes for rigid PVC formulations cover pipe, profile, sheet and foam, while flexible PVC formulations cover cable, film, flooring and plastisol, and the glycerol monostearate dosage split, 0.5 to 1.5 phr rigid against 0.5 to 1.0 phr flexible, illustrates the same pattern seen across the whole lubricant package.

How the package changes by application: pipe, window profile and cable#

The three largest PVC markets ask three different things of the lubricant: pipe wants throughput, window profile wants a uniform weldable surface, and cable wants release from a crosshead at high line speed. The full pipe package, including drinking-water compliance, sits on additives for PVC pipe, and weatherability and capstock rules for window profile compounds, where the capstock layer can reach up to 25 % of the wall thickness with about 10 % titanium dioxide over a substrate carrying about 15 % ground limestone, sit on additives for PVC window profiles. Cable compounds are plasticized and follow the flexible-PVC lubrication route rather than the rigid one.

Lubricants in other polymers: ABS, PS, polyamide and polycarbonate#

The same chemistries serve other polymers with a different emphasis: polycarbonate uses pentaerythritol tetrastearate at up to 0.5 wt% purely as a mould release, ABS and polyamide use magnesium stearate and ethylene bis stearamide, and unsaturated-polyester SMC uses zinc stearate. Magnesium stearate acts as an ABS and polyamide lubricant and dusting agent at 0.3 to 3 parts, and PETS is capped at 0.5 wt% of the finished resin in food-contact polycarbonate under 21 CFR 177.1580, where it works purely as a mould release rather than a processing lubricant. Mold release agents fall into four classes across every polymer that needs them: waxes, fatty esters, silicones and metallic soaps.

Is calcium stearate a lubricant or a stabilizer?#

Both: calcium stearate lubricates PVC and, in a calcium/zinc system, takes up the zinc chloride that zinc stearate generates, which makes it a co-stabilizer at the same time. The same substance also serves as a polyolefin acid scavengers and catalyst neutralizers at 0.05 to 0.20 %, an internal mould release in SMC, BMC and PLA, and a pigment wetting agent in colour concentrates.

Zinc stearate or calcium stearate: which one does what in PVC?#

Calcium stearate is the buffering, largely internal soap that melts at about 160 °C, and zinc stearate is the lower-melting, externally acting soap that substitutes labile chlorine, which is why the two are almost always used together and almost never alone. Their melting points, about 160 °C against about 120 °C in the Baerlocher range, follow directly from Baerlocher's internal/external classification and from zinc's specific role in taking up the chlorine that starts PVC degradation.

What lubricant is used for joining PVC pipe? (scope note)#

The water-based gasket and thread lubricants that plumbers use to push a PVC pipe into a socket are a separate product class: they are applied to the finished pipe, not compounded into the resin, and this reference covers only the additives that go into the compound. Readers searching for a pipe-joint or thread lubricant are looking for a plumbing product, not a compounding additive, and this page names no product and makes no recommendation for that use.

Are PVC lubricants toxic?#

The lubricants used in PVC today carry no harmonised EU hazard classification, and as of 22 September 2026 none of calcium stearate, zinc stearate, stearic acid, EBS, paraffin wax or oxidized PE wax is on the REACH Candidate List, a status tracked in full under the toxic plastic additives page. CLP self-classification notifications, not a harmonised classification, show calcium stearate not classified in 85.5 % of 3,808 notifications, zinc stearate not classified in 61.3 % of 2,108 (minority H400, H413 and H335 self-classifications), PETS not classified in all 416, and EBS not classified in 76.3 % of 1,846.

Lead stearate is the one historical exception: lead in PVC has been restricted to below 0.1 % under REACH Annex XVII entry 63, as amended by Regulation (EU) 2023/923, since 29 November 2024, with recovered rigid PVC allowed up to 1.5 % until 28 May 2033, deadlines covered in full under lead in PVC.

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Every figure on this page is checked against primary sources; see our methodology and fact-checking process.

Byline: PlasticAdditives.net Editorial Team

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