Additives for PVC: The Complete Formulation Guide to 14 Additive Families

A PVC compound draws on 14 additive families, and one of them is compulsory: polyvinyl chloride starts eliminating hydrogen chloride at 100 to 120 °C, so every PVC compound ever extruded contains a heat stabilizer. That single weakness pulls in a whole package, from 1 to 5 % of stabilizer in a rigid pipe compound to 65 wt% of plasticizer in a soft cable jacket, so which families does a given PVC recipe actually need?

The answer splits in two. The European Union uses about 60 % rigid PVC and about 40 % flexible PVC, and about 70 % of European PVC goes into building and construction (VinylPlus, 2023). A rigid recipe, written PVC-U, keeps every family in single figures: stabilizer, lubricants, acrylic processing aid, impact modifier and pigment all sit below 5 phr, and only the filler goes higher. A flexible recipe, written PVC-P, is built around the plasticizer at 5 to 65 wt% of the compound, and that liquid carries the stabilizer and the biocide into the melt with it. No other large-volume thermoplastic uses plastic additives at this density.

This guide follows a PVC compound from degradation to purchase order: the 14 families with their levels in phr, the rigid recipes for pipe, profile, siding, film, foam and CPVC, the flexible recipes for cable, flooring, film, plastisol and medical tubing, how a recipe is dosed and dry blended, which processing faults come out of the package, the four regulatory layers, the qualifying tests and the one-pack suppliers. Every family named here is one of the 43 families of plastic additives catalogued on this site.

The five rows below group the 14 families by the job they do inside the compound, from surviving the extruder to surviving outdoor service.

Levels are compound-dependent. Every value is sourced in the family sections below.

Why Does PVC Need More Additives Than Any Other Plastic?#

PVC needs 14 additive families because its own chlorine, 57 % of the mass of the polymer, makes it thermally unstable: unstabilized PVC eliminates hydrogen chloride at processing temperature, and a mere 0.1 % dehydrochlorination already discolours it beyond acceptance. Antifouling agents, suspending agents, polymerisation inhibitors and catalysts are polymer production aids under Article 3(8) of Regulation (EU) No 10/2011, not additives, so they are not among the 14.

Five properties of the raw polymer create the demand, and each pulls in a named family.

• Thermal instability opens the list: hydrogen chloride comes off from 100 to 120 °C and autocatalyses further loss, which makes a heat stabilizer compulsory.
• A narrow processing window follows: rapid degradation begins near 250 °C, barely above the melt temperature of a rigid compound, so the lubricant system and an acrylic processing aid have to deliver fusion without extra heat.
• Notch brittleness of the unmodified rigid polymer forces an impact modifier into every pipe, profile and siding recipe.
• Cost and stiffness targets bring in fillers, above all stearate-coated calcium carbonate, at 5 to 20 % in rigid articles and up to 70 phr in cable.
• The service environment adds the rest: benzotriazole absorbers and rutile titanium dioxide against ultraviolet light, aluminium trihydroxide and zinc borate for cable fire codes, biocides for damp flooring.

How does PVC degrade, and at what temperature?#

PVC degrades in two stages: it eliminates hydrogen chloride slowly from 100 to 120 °C, and rapidly near 250 °C, which is barely above the melt temperature of a rigid compound. Unstabilized PVC begins losing hydrogen chloride above about 70 °C, while polyethylene reaches its thermal degradation onset only at about 400 °C. The elimination runs as a zip reaction: once one chlorine leaves as hydrogen chloride, the neighbouring chlorine is activated, and the chain unzips into conjugated polyene sequences that absorb visible light, so the polymer turns yellow, then brown, then black. A mere 0.1 % dehydrochlorination already puts a compound outside colour acceptance, and the released hydrogen chloride is autocatalytic, which is why PVC thermal degradation accelerates once it has started.

Heat stabilizers interrupt that sequence at three points. They substitute the labile chlorine atoms at allylic and tertiary defect sites before elimination begins, they scavenge the hydrogen chloride already released so the autocatalytic loop cannot close, and they add across the polyene sequences to break up the conjugation that forms the colour.

How much of a PVC compound is additive?#

A rigid PVC pressure-pipe compound is about 7.4 wt% additive, while a flexible compound can be more than half additive. The rigid figure comes from the range composition published by the Plastics Pipe Institute (PPI TR-2, 2023 edition), whose worked example totals 108.03 phr for 100 parts of resin and leaves the resin at 92.57 wt%; the flexible figures come from the Huber Advanced Materials cable formulations.

In a rigid compound the stabilizer system accounts for 1 to 5 % of the formulation, the range published by the European Council of Vinyl Manufacturers, which Ullmann's Encyclopedia of Industrial Chemistry narrows to 2 to 4 % as typical. Everything else stays small: about 2 phr of lubricant in total, at most 2.0 phr of acrylic processing aid, 3 to 10 phr of impact modifier and 5.0 phr of filler inside the PPI pressure-pipe range.

In a flexible compound the arithmetic changes completely. Flexible PVC carries 5 to 65 wt% plasticizer, the Huber cable recipes carry 55 phr of diisodecyl phthalate before any mineral filler is counted, and medical PVC historically ran DEHP at up to 40 wt% in intravenous bags and up to 80 wt% in tubing. A single figure for how much of PVC is additive does not exist, because the rigid and the flexible compound are two different materials.

The 14 Additive Families in a PVC Formulation#

A PVC compound draws on 14 additive families: heat stabilizers, lubricants, acrylic processing aids, impact modifiers, plasticizers, fillers, colorants, UV stabilizers, flame retardants and smoke suppressants, blowing agents, antimicrobials, antistatic agents, antifog additives and optical brighteners.

Four of those families appear in almost every compound: a heat stabilizer, a lubricant system, a colorant and, in all but water-clear grades, a filler. Plasticizers define the flexible branch, and the remaining eight are specified by the end use. Three names used elsewhere are not separate families: co-stabilizers sit inside heat stabilizers, one-packs are a delivery form, and pigments sit inside colorants. The same families sit in a different order for every other plastic, which is what the additives by polymer overview compares.

Every example substance has its own record with CAS number, dosage and regulatory status in the plastic additives database.

1. Heat stabilizers: the one additive no PVC compound omits#

PVC heat stabilizers are metal soaps, organotin mercaptides and organic co-stabilizer systems that replace labile chlorine atoms and neutralise the hydrogen chloride PVC releases, at 1 to 5 % of the formulation. A calcium-zinc one-pack divides the work: the zinc carboxylate substitutes the labile chlorine quickly, the calcium carboxylate regenerates the zinc soap and takes up the hydrogen chloride, and the co-stabilizers block the zinc chloride the first reaction leaves behind. An organotin mercaptide does the same work in one molecule, exchanging its mercaptide ligand for the labile chlorine and forming a tin chloride that continues to scavenge acid.

Regional practice has diverged sharply. Calcium-zinc and calcium-organic systems account for 83 % of European stabiliser use (VinylPlus, June 2023), while the 2023 global picture is about 50 % calcium-based, 25.1 % lead and 15.4 % tin, the lead share sitting outside the European Union. North America stabilizes almost all of its rigid PVC with tin (Baerlocher), and the Plastics Pipe Institute range composition sets the methyltin level in US pressure pipe at 0.3 to 1.0 phr.

Calcium-zinc, organotin, lead and organic-based stabilizers compared#

PVC runs on 4 stabilizer systems: calcium-zinc and calcium-organic one-packs, organotin mercaptides, organic-based uracil systems and, as legacy only, lead salts.

The regional split is a regulatory artefact rather than a technical one. The European voluntary lead replacement was completed by the end of 2015: EU-15 lead stabiliser consumption fell from 127,156 tonnes in 2000 to 30,708 tonnes in 2010, according to the European Stabiliser Producers Association, and cadmium had already been phased out voluntarily from 2001 (ECVM). North America kept tin because its pressure-pipe specifications were written around tin-stabilized compounds, and the Plastics Pipe Institute range composition still specifies a tin heat stabilizer at 0.3 to 1.0 phr. Lead remains 25.1 % of the 2023 global figure because it is still used outside both regions, and it is written on this page as legacy and restricted, never as a current European option.

Co-stabilizers: epoxides, polyols, phosphites and beta-diketones#

Co-stabilizers are the second half of every calcium-zinc package: epoxidized soybean oil, polyols, organophosphites and beta-diketones each block a different failure route, above all the autocatalytic zinc chloride that causes zinc burning.

• Epoxides, principally epoxidized soybean oil, scavenge hydrogen chloride through their oxirane rings at 1 to 2 wt% as a stabilizer, against 25 to 45 wt% as the main plasticizer. ESBO is FCM 532, at 60 mg/kg and 30 mg/kg for infant-food jar gaskets.
• Polyols, above all pentaerythritol and dipentaerythritol, complex zinc chloride through their hydroxyl groups. The FDA limits pentaerythritol to 0.4 wt% in rigid PVC under 21 CFR 178.2010, and the EU lists it as FCM 279 with no SML.
• Organophosphites, such as triphenyl phosphite (CAS 101-02-0), bind zinc chloride, decompose hydroperoxides and preserve initial colour, at a typical 3 wt% in PVC per the ECHA mapping.
• Beta-diketones, dibenzoylmethane and stearoylbenzoylmethane, replace allylic chlorine by zinc-catalysed carbon alkylation (Michel and co-workers, 1981). The FDA limits stearoylbenzoylmethane to 0.5 wt% of vinyl chloride homopolymers, and the EU lists it as FCM 699.

Hydrotalcite (CAS 12304-65-3, FCM 604) joins the group as a layered acid scavenger: 2.4 phr hydrotalcite with 0.3 phr zinc stearate and 0.3 phr zinc acetylacetonate reached 190 minutes to blackening in a 180 °C oven. Which of the four classes a one-pack uses, and in what ratio, is set out on PVC co-stabilizers.

2. Lubricants: the internal and external balance#

Lubricants in PVC are paraffin waxes, metal stearates and oxidised polyethylene waxes that balance two opposite jobs: internal lubricants lower friction inside the melt, external lubricants keep the melt off hot metal, and a rigid pipe package uses 0.6 to 1.5 phr of each. The balance decides the fusion level. Paraffin wax delays particle breakdown and therefore delays fusion, while calcium stearate wets hot metal preferentially, as Rabinovitch and co-workers showed in 1984, and either accelerates or delays fusion depending on the melt temperature and the amount of paraffin present, a dual behaviour reported by Krzewki and Collins in 1981.

Each process carries its own package, and the Struktol technical data sheets give the levels. A pressure-pipe compound uses 0.6 to 1.5 phr paraffin, 0.6 to 1.5 phr calcium stearate and 0.1 to 0.2 phr oxidised polyethylene wax; a profile compound narrows this to 0.8 to 1.2 phr paraffin and 0.8 to 1.2 phr calcium stearate with the same oxidised wax. Injection moulding uses 0.3 to 1.0 phr calcium stearate and calendering 0.3 to 0.75 phr, while clear injection moulding replaces the stearate with 0.7 to 1.0 phr hydroxyl glycerol ester and 0.3 to 0.6 phr complex ester.

3. Acrylic processing aids#

Acrylic processing aids are high-molecular-weight methacrylate copolymers that entangle with PVC chains, raise melt strength and shorten fusion time, and the PPI range composition allows up to 2.0 phr of them in a pressure-pipe compound. The mechanism is entanglement rather than lubrication: the acrylic raises mixing torque, wall shear stress and extrudate swell, the opposite of what a lubricant does, and it moderates sharkskin at the die. A methyl methacrylate copolymer with butyl acrylate is more effective than the ethyl acrylate version at the same molecular weight.

Levels published outside the PPI document come from supplier literature rather than from a primary source, so the sourced range for a US pressure-pipe compound is 0.0 to 2.0 phr, with 0 phr in the worked example.

4. Impact modifiers#

Impact modifiers for PVC are rubbery core-shell acrylics, MBS and chlorinated polyethylene that disperse as micron-scale particles and stop a notch from running, at an effective 3 to 10 phr. Below 3 phr there is no useful strength effect, and above 10 phr the gain in notched impact strength flattens out while modulus and heat resistance keep falling, a boundary established in the patent literature.

Chemistry follows the article. Acrylic core-shell modifiers go into weatherable outdoor profiles and siding, because the acrylic shell carries no unsaturation for ultraviolet light to attack. MBS goes into clear rigid film and bottles, because its refractive index can be matched to PVC. Chlorinated polyethylene is the cost option for pipe and profile at 1 to 10 phr, preferably 2.5 to 7.0 phr, while an MBS or ABS graft copolymer is used at 5 to 6 phr in CPVC.

5. Plasticizers#

Plasticizers are low-volatility esters that sit between PVC chains and lower the glass transition temperature, and flexible PVC contains 5 to 65 wt% of them, with antiplasticization below about 15 phr. The ester group solvates the polar carbon-chlorine dipoles and pushes the chains apart, moving the compound from Shore A 90 down to 50 as the level rises. Below about 15 phr the opposite happens: too little plasticizer fills free volume without separating the chains, and the compound becomes harder and more brittle than the unplasticized polymer. The ECHA Plastic Additives Initiative mapping gives 10 to 35 wt% as the typical concentration in soft PVC, inside the wider 5 to 65 wt% band.

Flexible PVC is the destination of the plasticizer industry: more than 85 % of European plasticizer volume goes into it (European Plasticisers), out of a global 8.4 million tonnes a year. The European substance set has turned over almost completely. DEHP (CAS 117-81-7) is legacy, and the volume now sits with the high-molecular-weight ortho-phthalates DINP, DIDP and DPHP, the terephthalate DOTP or DEHT (CAS 6422-86-2), the cyclohexanoate DINCH (CAS 166412-78-8), the trimellitate TOTM for high-temperature cable, and epoxidized soybean oil.

6. Fillers#

Fillers in PVC are ground and precipitated calcium carbonate grades, usually stearate-coated, that cut cost and raise stiffness, at 5 to 15 % in a window profile, 15 to 20 % in a drainpipe and up to 70 phr in a cable compound. The stearate coating is not cosmetic: it stops the mineral picking up moisture, improves dispersion in the dry blend and reduces plate-out on dies and calender rolls. Fine ground grades also act as an impact co-modifier in rigid PVC, which allows part of the more expensive modifier to be removed.

The regulated end of the scale is narrower than the commercial one. The PPI TR-2 range composition allows 0.0 to 5.0 phr of calcium carbonate in a classified pressure-pipe compound, and the worked example uses the full 5.00 phr, equal to 4.63 wt%. Window profiles, drainpipes and cable jackets sit far above that, because none of them carries a hydrostatic design basis.

7. Colorants and titanium dioxide#

Colorants in PVC are rutile titanium dioxide and organic and inorganic pigments that give colour, opacity and, in the case of titanium dioxide, most of the outdoor durability of a white profile, at 0.5 to 3.0 phr in pipe and about 10 % in a siding capstock. Rutile grades scatter visible light for opacity and absorb ultraviolet light before it reaches the polymer, which is why a weathering grade is specified for any article exposed outdoors. The PPI worked example uses 0.50 phr of titanium dioxide plus 0.03 phr of pigment, and the ECHA mapping gives about 2 wt% as the typical organic pigment concentration in PVC.

Two regulatory points belong with this family. Titanium dioxide has no harmonised classification in force in the European Union: the General Court annulled the Carc. 2 entry on 23 November 2022, and the Court of Justice dismissed the appeals on 1 August 2025. Lead chromate pigments went the other way, on the REACH Candidate List since 13 January 2010 and on Annex XIV with a sunset date of 21 May 2015.

8. UV stabilizers#

UV stabilizers for PVC are benzotriazole and benzophenone UV absorbers, supported by the screening effect of rutile titanium dioxide, at 0.3 to 0.5 wt% in the bulk and up to 5 wt% in a co-extruded cap layer. The absorber converts ultraviolet energy into heat through a reversible intramolecular proton transfer, protecting the carbon-chlorine bonds at defect sites from the photolytic cleavage that would start the same polyene sequence heat starts. BASF and Mayzo technical data place the general PVC range at 0.2 to 5.0 wt%, the high end reserved for thin cap layers.

Two constraints apply in PVC that do not apply in polyolefins. Food-contact use is capped by 21 CFR 177.1980, which limits one benzotriazole absorber to 0.25 wt% in rigid PVC. Hindered amine light stabilizers, the workhorse of polypropylene, are used with care in PVC, because the hydrogen chloride the polymer releases neutralises the hindered amine and removes its regeneration cycle.

9. Flame retardants and smoke suppressants#

Flame retardants in PVC work on smoke and dripping rather than on ignition, because 57 % chlorine already makes the polymer hard to burn, and a cable insulation compound reaches a limiting oxygen index of at least 26 vol% oxygen with 45 to 100 phr of aluminium trihydroxide and 3 to 6 phr of zinc borate. Aluminium trihydroxide releases water of crystallisation endothermically and dilutes the combustion gases, raising the limiting oxygen index and cutting heat release at once. It is dosed in tens of parts, which is why a flame-retarded cable compound is the most heavily filled PVC compound in service.

Zinc borate at 3 to 6 phr promotes char, reduces dripping and smoke and helps a compound pass DIN 4102 and EN 13501. Antimony trioxide appears at 5 phr in the Huber comparison formulations, using the chlorine already in the polymer as its halogen source. Zinc hydroxystannate is used at 3 to 5 phr in research formulations as an antimony-free alternative, and molybdenum trioxide and ammonium octamolybdate are added specifically as smoke suppressants.

10. Blowing agents#

Blowing agents in PVC are chemical types, mainly azodicarbonamide with a zinc kicker, that release gas inside the fusing plastisol or melt and create the cell structure of cushion vinyl, wallpaper and foamed profile. Azodicarbonamide alone decomposes well above the plastisol fusion temperature, so the kicker matters: zinc compounds lower the decomposition temperature into the 140 to 220 °C fusion range, which lets a printed cushion vinyl expand exactly where the inhibitor was not printed.

Azodicarbonamide has been on the REACH Candidate List since 19 December 2012 as a respiratory sensitiser, which drives converters towards enclosed handling and masterbatch dosing. No primary source on file gives a dosage for azodicarbonamide in a PVC foam recipe, so none is stated here.

11. Antimicrobials#

Antimicrobial additives in PVC are biocides such as OBPA, DCOIT and zinc pyrithione, supplied dissolved in the plasticizer, and flexible PVC took about two-thirds of the world's plastics biocide volume in 2005. The carrier is why this is a flexible-PVC family: the biocides arrive as solutions in DIDP, DIHP or DINP, so a rigid compound with no liquid phase has no easy route to dose them. OBPA was the largest plastics biocide by volume in 2005, at more than one third of the total, while DCOIT gives better ultraviolet resistance and is preferred in roofing membranes, pool liners, flooring, signs and wallcoverings.

A treated PVC article sits under the EU Biocidal Products Regulation, which governs the active substance and the claims made for the article.

12. Antistatic agents#

Antistatic agents in PVC are ionic surfactants and glycerol monostearate that draw a thin moisture film to the surface and drain static charge, at 0.5 to 1.5 phr in rigid PVC. Ionic antistats suit polar resins such as PVC and are not used in polyethylene, where their low heat stability fails at polyolefin processing temperatures. The Struktol data give 0.5 to 1.5 phr for rigid PVC and 0.5 to 1.0 phr for flexible PVC.

Glycerol monostearate earns its place twice over, working as an internal lubricant in the melt and as an antistat at the surface.

13. Antifog additives#

Antifog additives in PVC are non-ionic surfactants that spread condensed water into a transparent layer on cling film, at 0.5 to 1.0 % for refrigerated packs and 0.3 to 0.6 % for hot-filled ones. The additive migrates to the surface and lowers the surface tension of the condensate, so the water wets out as a continuous film instead of light-scattering droplets.

Cold fog and hot fog are two specifications, which is why the Palsgaard Einar 211 data sheet gives two levels. In the United States, 21 CFR 178.3130 limits the glycerol ricinoleate ester mixture used for this purpose to 1.5 wt% in plasticized PVC.

14. Optical brighteners#

Optical brighteners in PVC are fluorescent whitening agents that absorb ultraviolet light and re-emit it as blue, masking the yellow tint of a heat-stressed compound, at 50 to 1,000 ppm, equal to 0.005 to 0.1 %. The blue emission cancels the yellow absorption of short polyene sequences, so the yellowness index falls without any change to the stabilizer package.

Higher loadings are combined with a UV absorber, because the brightener is itself consumed by the ultraviolet light it absorbs. US food-contact use is capped by 21 CFR 178.3297 at 0.015 % under conditions A to H, or 0.05 % for the listed food types.

Rigid PVC (PVC-U) Formulations by Application#

Rigid PVC formulations differ mainly in their stabilizer and lubricant choice, not in their overall additive load: pipe, profile, siding, film and foam all keep every additive except the filler below 5 phr. Rigid PVC is about 60 % of European consumption, so the five recipes below cover most of the tonnage. The recipe-by-recipe detail for pipe, profile, sheet and foam is on rigid PVC formulations.

US pressure pipe: the PPI TR-2 range composition#

The Plastics Pipe Institute publishes the only PVC formulation with regulatory standing: the TR-2 range composition for PVC 1120 pressure pipe, cell class 12454 under ASTM D1784, with a hydrostatic design basis of 4,000 psi (27.58 MPa) at 73.4 °F (23 °C). A compound that stays inside the published ranges is exempt from new stress-rupture testing, which is why the document functions as a recipe rather than as an illustration. The stabilizer is a tin mercaptide at 0.3 to 1.0 phr, calcium stearate the internal lubricant and fusion promoter, paraffin wax the external lubricant and oxidised polyethylene wax a secondary external lubricant.

A potable-water compound must also clear NSF/ANSI 61 and NSF/ANSI 14, the US counterpart of the EU positive lists for plastic additives in drinking-water contact. The FDA caps on the same tin chemistry are 2 wt% methyltin in rigid PVC under 21 CFR 178.2010 and 3 phr total organotin under 178.2650, both well above the pipe level. Stabilizer choice, ultraviolet resistance and drinking-water compliance for pipe are compared on additives for PVC pipe.

Range composition from PPI TR-2-2023 Table 1; worked example from Appendix C. Weight percent equals phr divided by the total phr, times 100.

Window and technical profiles#

A European window profile is stabilized with a calcium-zinc or calcium-organic one-pack and carries four more families: an acrylic impact modifier at 3 to 10 phr, weathering-grade titanium dioxide, 5 to 15 % coated calcium carbonate and an acrylic processing aid. The filler is stearate-coated chalk or ground marble, chosen for low moisture pick-up and low plate-out rather than for price alone. Baerlocher's PVC brochure of 2019 describes the same package for white, coloured, coextruded and foamed profiles produced by the free-foam and Celuka routes, and names accurate initial colour, weathering and low plate-out as the properties the one-pack is selected on.

No complete phr recipe for a European window profile exists in a primary public source, and none is invented here. Suppliers publish one-pack dosing rather than full recipes, because the pack already contains the stabilizer, the co-stabilizers and part of the lubricant system, and its dose is set against the resin, extruder and die. The sourced component ranges are 3 to 10 phr of impact modifier, 5 to 15 % of coated filler, and a profile lubricant package of 0.8 to 1.2 phr paraffin, 0.8 to 1.2 phr calcium stearate and 0.1 to 0.2 phr oxidised polyethylene wax. The one-pack, impact modifier and titanium dioxide choices for a white profile are compared on additives for PVC window profiles.

Vinyl siding#

Vinyl siding splits its additive package between two layers: the weatherable capstock, up to 25 % of the wall thickness, can carry about 10 % titanium dioxide, while the substrate underneath is typically about 15 % ground limestone. That puts the weathering package only where sunlight reaches it and the cheap mineral only where stiffness is needed. About 80 % of the weight of a siding panel is PVC resin, stabilized with a small quantity of tin mercaptide in the North American practice described above. The capstock also carries the acrylic impact modifier, because an acrylic shell survives ultraviolet exposure where a diene-based modifier would chalk and fail.

Rigid film, sheet and foam#

Rigid PVC film and sheet for blisters, labels, cards and shrink sleeves are still mostly stabilized with tin mercaptides, because clarity and early colour are the controlling properties. Tin-free alternatives are growing (Baerlocher), and the calendering lubricant package is 0.7 to 1.5 phr hydroxyl glycerol ester, 0.5 to 0.75 phr complex ester, 0.3 to 0.75 phr calcium stearate and 0.07 to 0.15 phr oxidised polyethylene wax. Clear injection moulding narrows this further, to 0.7 to 1.0 phr hydroxyl glycerol ester and 0.3 to 0.6 phr complex ester.

Foamed sheet and profile are made by the free-foam and Celuka processes with a chemical blowing agent, and they need the high end of the acrylic processing aid range to hold the cell walls. One regulatory point governs the clear rigid segment: DOTE is the classic clear-rigid stabilizer, its European authorisation sunset date was 1 May 2025, and food-contact uses sit outside that authorisation.

CPVC#

CPVC carries the same families as rigid PVC at higher loadings, because chlorinating the polymer to between 56.7 and 74 % chlorine, with most commercial grades in the mid-to-high 60s according to Reagens, raises its Vicat softening point and glass transition temperature to 106 to 115 °C and narrows the processing window further. The maximum service temperature rises to about 93 °C (200 °F), but the melt then sits closer to its own degradation onset. Reagens describes the answer as a tin superpack, an impact modifier and a lubricant system dosed above the PVC levels: chlorinated polyethylene at 1 to 10 phr and preferably 2.5 to 7.0 phr, or an MBS or ABS graft copolymer at 5 to 6 phr. The stabilizer side is covered separately under heat stabilizers for CPVC.

Flexible PVC (PVC-P) Formulations by Application#

Flexible PVC formulations are built around the plasticizer, which sets hardness, low-temperature flexibility, migration behaviour and most of the cost at 5 to 65 wt% of the compound. Flexible PVC is about 40 % of European consumption, and its recipes differ from the rigid ones in delivery form as much as in chemistry: the stabilizers are liquid mixed-metal systems rather than powder one-packs. In the European Union, calendered flexible films use almost solely barium-zinc and calcium-zinc systems, flooring uses liquid calcium-zinc, barium-zinc and potassium-zinc systems with a kicker for the foamed layers, and plastisols gel and fuse between 140 and 220 °C. Cable, film, flooring and plastisol recipes are set out on flexible PVC formulations.

Cable insulation and sheathing#

A PVC cable insulation compound is the most crowded formulation in this guide: 100 parts of K-70 resin carry 55 phr of plasticizer, 2.7 phr of lead-free stabilizer, 45 to 100 phr of aluminium trihydroxide, 5 phr of zinc borate and 10 phr of chalk, and it still has to reach a limiting oxygen index of at least 26 vol% oxygen. The plasticizer in the published Huber Advanced Materials formulations is diisodecyl phthalate, and the mineral load distinguishes the three variants: replacing part of the aluminium trihydroxide with chalk and zinc borate keeps the same fire result at lower cost.

Reagens lists PVC cable classes at 70, 90, 100/105 and 125 °C, each demanding a different stabilizer and plasticizer volatility. Fire performance is where the additive package earns its place: all three formulations below reach UL 94 V-0 at 3 mm and a limiting oxygen index of 26 to 27 %, while 3 to 6 phr of zinc borate reduces dripping and smoke and helps a compound pass DIN 4102 and EN 13501. Smoke remains the hard limit, because even at 150 phr of aluminium trihydroxide a plasticized PVC compound still smokes more than a halogen-free reference with 160 phr of the same mineral in EVA and LLDPE. How a PVC jacket compares with a low-smoke halogen-free compound on smoke is covered in additives for wire and cable compounds.

Supplier formulations published by Huber Advanced Materials. The three differ in mineral loading; all three reach a limiting oxygen index of 26 to 27 % and UL 94 V-0 at 3 mm.

Flooring, calendered film and plastisols#

Flexible PVC flooring, calendered film and plastisol all use liquid mixed-metal stabilizers rather than the powder one-packs of rigid PVC, because the plasticizer itself carries the stabilizer into the compound. Baerlocher's flooring package is a liquid calcium-zinc, barium-zinc or potassium-zinc system with a kicker in the foamed layer, an organophosphite booster and epoxidized soybean oil, covering compact and homogeneous floorings, cushion vinyl, luxury vinyl tile and rigid-core SPC and WPC tiles. Design floor coverings grew from about 500 million m2 in 2018 to about 920 million m2 in 2023.

The four flexible outlets below each set a different controlling property, and the additive package follows it.

• Flooring is specified on wear-layer durability, foam structure and emissions, so it takes a liquid mixed-metal stabilizer, a kicker in the foamed layer and a biocide in damp installations.
• Calendered film for furniture, lamination, adhesive tape, cling film and waterproofing membranes uses almost solely barium-zinc and calcium-zinc systems in the European Union, with emissions, fogging and odour as the controlling properties, and cling film adds an antifog surfactant at 0.5 to 1.0 %.
• Plastisol for coated fabrics, tarpaulins, flooring and automotive underbody coatings is mixed as a liquid and fuses at 140 to 220 °C, the same window a blowing agent has to decompose inside. The liquid phase is covered under plasticizers for PVC plastisol.
• Coated fabric for tarpaulins, tents and truck curtains uses the same plastisol route plus the outdoor package: a UV absorber, weathering-grade titanium dioxide and a biocide.

Medical PVC and the move away from DEHP#

Medical PVC is the highest-plasticizer application of all: DEHP was used at up to 40 wt% in intravenous bags and up to 80 wt% in tubing, and measured contents in tubing run from 34.9 to 48.7 wt%. Bernard and co-workers reported in 2018 the measured contents of PVC medical tubing across four chemistries: DEHP 34.9 to 48.7 wt%, TOTM 30.3 to 41.0 wt%, DINCH 30.2 to 44.3 wt% and DEHT 26.7 to 37.5 wt%. Sterilization stability and biocompatibility decide the rest of the package, as set out in additives for medical plastics, with biocompatibility tested to ISO 10993-1:2025, ISO 10993-17:2023 and ISO 10993-18:2020.

The substitution is now a dated legal obligation rather than a preference. The EU sunset date for DEHP in medical devices is 1 July 2030, with a latest application date of 1 January 2029 under Regulation (EU) 2023/2482, and Annex I section 10.4.1 of the Medical Devices Regulation already requires justification and labelling for CMR 1A or 1B and endocrine-disrupting substances above 0.1 % w/w. The FDA published its Public Health Notification on DEHP in PVC medical devices on 12 July 2002, so the replacements have two decades of clinical history behind them.

How Are PVC Additives Dosed and Mixed In? phr, One-Packs and Dry Blending#

PVC additive levels are given in phr, parts per hundred parts of resin, so a recipe always starts at 100 and its total exceeds 100: the PPI pressure-pipe example totals 108.03 phr, which makes the resin 92.57 wt% of the compound. The conversion from PHR (parts per hundred resin) to weight percent divides each part by the recipe total and multiplies by 100, so 5.00 phr of calcium carbonate becomes 4.63 wt%. The two units are never mixed in one sentence without a label, because a 55 phr and a 55 wt% plasticizer level describe different compounds.

A one-pack combines the stabilizer, the co-stabilizers and part of the lubricant system in a single powder or pellet, which is why suppliers publish a pack dose rather than individual phr values. The six steps below build a recipe from the resin outwards.

1. Start from 100 parts of resin, chosen by K value for the process.
2. Set the stabilizer system from the process temperature and the regulatory target, which decides calcium-zinc, organotin or organic-based.
3. Balance the internal and external lubricants against fusion and metal release, checking the fusion level on a torque rheometer.
4. Add the impact modifier or the plasticizer, depending on whether the compound is rigid or flexible.
5. Add filler, pigment and the function additives the end use requires.
6. Convert the finished recipe to weight percent and to cost per kilogram before comparing suppliers.

Run a finished recipe through the PHR to weight percent calculator, because a quote per kilogram of one-pack and a quote per kilogram of compound are not the same thing.

Rigid compounds reach the extruder as a dry blend: frictional heat in a hot mixer opens the resin particles so the liquid additives are absorbed, and a cold mixer then cools the blend before it agglomerates. Order of addition controls how the liquids are taken up, and it is covered on PVC dry blending. Plastisols follow the opposite route, dispersed cold and fused later at 140 to 220 °C.

Which Processing Problems Come From the Additive Package?#

Five PVC processing faults trace straight back to the additive package: plate-out, zinc burning, yellowing and pinking, poor fusion and excessive die swell, each with a named cause and a named fix in the recipe itself.

• Plate-out is a deposit of stabilizer, lubricant and pigment that builds up on dies, calender rolls and mould surfaces and forces an unplanned stop. Stearate-coated fillers and a rebalanced external lubricant reduce it, and the mechanism is set out on plate-out in PVC processing.
• Zinc burning is the sudden blackening of an over-zinced calcium-zinc compound, caused by the autocatalytic zinc chloride formed once the zinc carboxylate has been consumed. Polyols, organophosphites, beta-diketones and hydrotalcite each block it, which is why a calcium-zinc one-pack is never zinc alone.
• Yellowing and pinking come from two routes: yellowing from the polyene sequences left by dehydrochlorination, pinking from over-oxidised phenolic species. Both are worked through under why plastics turn yellow or pink.
• Poor fusion shows up as low melt strength, poor weld lines and low impact strength, and its cause is the lubricant balance: paraffin delays particle breakdown, while calcium stearate accelerates or delays fusion depending on temperature and paraffin content.
• Excessive die swell distorts profile dimensions at the die exit, and calcium stearate reduces it in rigid PVC, which makes the same lubricant a dimensional tool.

Remaining thermal stability ties these faults together, and the Congo red test of ISO 182-1:1990 measures what is left. Each fault and its additive fix is worked through in troubleshooting additive-related defects.

How Is PVC Regulated Through Its Additives?#

PVC is regulated through its additives in 4 layers: REACH restrictions and authorisations on the metals and plasticizers themselves, food-contact positive lists, drinking-water positive lists, and product rules for toys, medical devices and packaging. The polymer itself is not restricted in the European Union. ECHA's PVC investigation of November 2023 assessed 63 additives used as heat stabilizers, plasticizers and flame retardants in PVC and concluded that restrictions may be needed, which is the current status of the file. The four layers are set out in full in our guide to plastic additive regulations.

Lead, cadmium and organotins under REACH Annex XVII#

Lead in PVC has been limited to less than 0.1 % by weight of the PVC material since 29 November 2024, under entry 63 of REACH Annex XVII as amended by Commission Regulation (EU) 2023/923 of 3 May 2023, and articles placed on the market before that date are exempt. Recovered rigid PVC is the one broad derogation: it may contain less than 1.5 % lead until 28 May 2033 in listed uses, namely external building profiles and sheets, hidden building spaces, interior layers and the middle layer of multilayer pipes, fittings and decking cores outside drinking-water contact, each marked "Contains >= 0,1 % lead". The closed-loop condition attached to that derogation applies from 28 May 2026, and the Commission review is due by 28 May 2028. The equivalent derogation for recovered flexible PVC expired on 28 May 2025, so the general 0.1 % limit now applies to it. Every date, derogation and marking rule is listed on lead in PVC.

Cadmium and the organotins are older files. Entry 23 limits cadmium to 0.01 % by weight in PVC, with recovered PVC in listed rigid building uses allowed up to 0.1 %, and European producers had already phased cadmium out voluntarily from 2001 (ECVM). Entry 20 limits dibutyltin and dioctyltin compounds to 0.1 % by weight of tin in listed articles and mixtures from 1 January 2012, with the dibutyltin derogations ending on 1 January 2015, and caught the tri-substituted organotins from 1 July 2010. DOTE needs an authorisation on top of that, with a sunset date of 1 May 2025. Entries 20, 23, 51, 52 and 63 all sit in the same annex, compared on REACH Annex XVII restrictions.

Phthalates in PVC: entries 51 and 52, authorisation and food-contact SMLs#

Four low-molecular-weight ortho-phthalates have been limited to 0.1 % in all EU articles since 7 July 2020: DEHP, DBP, BBP and DIBP, under entry 51 of REACH Annex XVII. Entry 52 is narrower and often misread: it covers DINP, DIDP and DNOP in mouthable toys and childcare articles only, so DINP is not banned in the European Union and a DINP-plasticized cable or flooring compound remains lawful. The split between low and high molecular weight decides the legal status of phthalate plasticizers, and it also decides the food-contact position: Regulation (EU) 2023/1442, in force since 1 August 2023, sets specific migration limits of 0.6 mg/kg for DEHP, 0.12 mg/kg for DBP and 6 mg/kg for BBP, with group restriction 26 (DINP plus DIDP) at 1.8 mg/kg and group restriction 36 at 0.6 mg/kg expressed as DEHP equivalents.

The United States has moved on a different track. The FDA final rule of 20 May 2022 left exactly 8 ortho-phthalates authorised as food-contact plasticizers, and the FDA action of 27 May 2026 on DEHP, DCHP, DIOP and DINP is a proposal. Under TSCA, the EPA noticed final risk evaluations for BBP, DBP, DCHP, DEHP and DIBP on 6 January 2026 (91 FR 373), and DEHP carries the harmonised EU classification Repr. 1B (H360FD). The largest non-ortho-phthalate replacement in PVC is DOTP, followed by DINCH, TOTM, DPHP and the citrates, none of which is on the Candidate List.

Food contact and drinking water: EU 10/2011, 21 CFR and NSF/ANSI 61#

A food-contact PVC compound may use only additives on the Union list of Regulation (EU) No 10/2011, within an overall migration limit of 10 mg/dm2 and each substance's specific migration limit, and the organotin stabilizers carry the tightest of them at 0.006 mg/kg of tin for di-n-octyltins. The generic specific migration limit is 60 mg/kg, the overall limit falls to 60 mg/kg for infant articles, and a functional barrier has to hold any non-listed substance below 0.01 mg/kg. The other stabilizer entries are methyltins at 0.18 and mono-n-octyltins at 1.2 mg/kg as tin, estertin (FCM 710) at 18 mg/kg, 2-phenylindole (FCM 383) at 15 mg/kg, dihydropyridine (FCM 761) at 6 mg/kg and aminouracil (FCM 495) at 5 mg/kg. The Union list and its migration limits are explained on EU 10/2011.

The United States regulates the same compound by section rather than by list. 21 CFR 178.2010 specifies the methyltin stabilizer itself, at 15 to 21 % tin with trimethyltin below 0.4 %, and allows it up to 2 wt% in rigid PVC for food contact up to 88 °C; 178.2650 caps total organotin at 3 phr; and 181.29 carries the prior-sanctioned stabilizers, stannous stearate, zinc orthophosphate and zinc resinate, with a 50 ppm migrant limit. The US caps sit in 21 CFR, summarised on FDA food contact rules. Drinking water is a third regime: the EU positive lists under Commission Implementing Decision (EU) 2024/367 apply from 31 December 2026, with methyltin as entry 0606 and dimethyltin as entry 0561 to be reviewed by 31 December 2028, while US potable-water PVC pipe needs NSF/ANSI 61 and NSF/ANSI 14 certification.

How Is a PVC Compound Tested?#

A PVC compound is judged on thermal stability first: the Congo red test of ISO 182-1:1990 measures the time until hydrogen chloride breaks through, at a temperature the laboratory sets, usually 180 or 190 °C. Static oven ageing at 180 °C runs alongside it and reports the time to blackening: the hydrotalcite formulation cited earlier reached 190 minutes against a Congo red maximum of 46 minutes in the same study. Fire performance comes second, and the compound class and weathering tests follow. The six property groups below are the ones a PVC specification names.

UL 94 V-0, the rating the cable formulations above reach at 3 mm, allows each afterflame at most 10 seconds, at most 50 seconds in total for five specimens, and no flaming drips that ignite the cotton below. Yellowness index is reported to ASTM E313 and never to the withdrawn ASTM D1925. Thermal stability testing and smoke density testing each have their own method pages on this site.

Who Supplies PVC Additives and One-Packs?#

The global PVC stabilizer market is worth USD 4.6 billion (2024, IMARC) and is forecast at USD 6.9 billion by 2033, and it is supplied by a small group of one-pack specialists rather than by the large diversified additive groups. That structure follows from the product: a one-pack is a formulation service matched to a customer's resin, extruder and specification, so the business is regional and technical. About 20,000 tonnes of tin a year go into PVC stabilization, an order-of-magnitude figure rather than a measured one. Regional demand follows the chemistry: calcium-based systems dominate Europe at 83 % of stabiliser use, tin dominates North American rigid PVC, and India consumes about 3,700 kilotonnes of PVC a year, about 75 % of it in pipes and fittings, according to supplier data from Platinum Industries. The wider field is listed in the plastic additive manufacturers and suppliers directory.

Company data from our source library. No company on this page pays for placement; see our editorial policy. Plasticizer suppliers are listed separately under plasticizer manufacturers and suppliers.

Metal stearate suppliers and the individual company profiles, including Baerlocher, have their own directory entries. Plasticizer is the largest line in a flexible recipe, so track plasticizer prices before quoting.

What Do PVC Additives Mean for Health, Recycling and the Environment?#

The health and environment debate around PVC is a debate about three legacy additive groups, not about the polymer: lead stabilizers, low-molecular-weight ortho-phthalates and organotins, all three now restricted in the European Union. The current European package, calcium-zinc with organic co-stabilizers and high-molecular-weight or non-phthalate plasticizers, carries none of those classifications. What keeps the file open is that PVC articles last for decades, so the legacy substances are still in service and still entering the recycling stream. ECHA's investigation of November 2023 assessed 63 additives used in PVC as heat stabilizers, plasticizers and flame retardants and concluded that restrictions may be needed, a conclusion that has not yet become a restriction proposal. The full list of chemicals of concern across all polymers is on toxic plastic additives.

Which PVC additives are restricted or toxic?#

Four PVC additive groups are restricted in the European Union: lead salts, the low-molecular-weight ortho-phthalates DEHP, DBP, BBP and DIBP, the octyltin stabilizer DOTE with its MOTE reaction mass, and the medium-chain chlorinated paraffins used as secondary plasticizers.

• Lead salts, including tribasic and tetrabasic lead sulfate and dibasic lead phosphite, have been on the REACH Candidate List since 19 December 2012 as toxic for reproduction, and lead has been restricted in PVC below 0.1 % since 29 November 2024.
• DEHP carries the harmonised classification Repr. 1B (H360FD), sits in Annex XVII entry 51 and Annex XIV, and has been on California Proposition 65 since 1 January 1988. The human-health evidence is reviewed on phthalates: health effects.
• DOTE has been on the Candidate List since 17 December 2014 and on Annex XIV with a sunset date of 1 May 2025, so its use needs an authorisation and food contact sits outside it.
• Medium-chain chlorinated paraffins entered Stockholm Annex A at COP-12 in 2025, and the EU delegated regulation C(2026) 6262 of 11 September 2026 is adopted but not yet in force, with an unintentional-trace limit of 0.1 % w/w and a two-year allowance of 2 % for recovered PVC from cable recycling.

The replacements now used in European compounds, calcium-zinc systems, DOTP, DINCH and TOTM, are not on the Candidate List.

Do plasticizers leach out of PVC over time?#

Yes: plasticizers are not chemically bound to PVC, so they migrate slowly to the surface and into fatty foods, oils and solvents, which is why the European Union limits DEHP migration into food to 0.6 mg/kg under Regulation (EU) 2023/1442. Rate depends on molecular weight: polymeric and high-molecular-weight plasticizers migrate far less than DEHP does. Migration and extraction testing is covered on additive migration in plastics, by the loss-in-contact methods of ISO 177 and ASTM D1239.

Can recycled PVC still contain lead and DEHP?#

Yes, within a legal limit: recovered rigid PVC may contain up to 1.5 % lead until 28 May 2033 in a defined list of building applications, provided the article is marked "Contains >= 0,1 % lead". A closed-loop condition applies from 28 May 2026 and a Commission review is due by 28 May 2028, while the flexible-PVC derogation expired on 28 May 2025. Restabilization and the derogation conditions are on recycled PVC.

Measurement confirms that legacy additives travel with the material. Wiesinger and co-workers at ETH Zurich analysed 151 Swiss PVC floorings for Environmental Science and Technology in 2024: 16 % contained regulated chemicals above 0.1 wt%, mainly lead and DEHP, DEHP was detected in 19 % of samples at 0.003 to 20 wt%, and zinc, barium and tin appeared in 96 %, 72 % and 58 %. Lead, cadmium and phthalates travel with the recyclate, as set out in legacy additives in recycled plastic.

What kind of PVC is food safe?#

Food-safe PVC is PVC whose every additive appears on the Union list of Regulation (EU) No 10/2011 and stays within its specific migration limit, which in practice means an organic-based, calcium-based, estertin or methyltin stabilizer rather than an octyltin or a lead salt. The organic-based route runs on aminouracil (FCM 495, SML 5 mg/kg), the estertin route on FCM 710 at 18 mg/kg and the methyltin route on group 9 at 0.18 mg/kg as tin, and an ESBO gasket on an infant-food jar is capped at 30 mg/kg rather than 60 mg/kg.

In the United States the same compound is cleared section by section: 21 CFR 178.2010 allows methyltin at up to 2 wt% in rigid PVC for food contact up to 88 °C, and the plasticizer caps sit in 178.3740. No additive is "FDA approved" in the abstract; it is cleared for a stated condition of use, at a stated level, in a stated polymer.