Processing Aids for PVC (Acrylic Processing Aids): 3 Grade Types, Dosage and Selection

Processing aids for PVC are high-molecular-weight acrylic copolymers, made from methyl methacrylate with ethyl or butyl acrylate, that are dry-blended into a PVC compound at a few parts per hundred resin to make it fuse faster and more evenly and to give the melt enough strength to hold its shape. They are the additive that turns a powder blend into a processable melt, which is why rigid PVC pipe, window profile and foam formulations almost all contain one; so which grade, and how much?

PVC uses more distinct additive families than any other commodity polymer, and the processing aid is the one that acts on the compound rather than on the finished part, which makes it unlike most plastic additives.

This page covers the fusion mechanism, the 3 grade types, dosage by application from pipe to foam board, how a processing aid interacts with the lubricant package that works against it, how the effect is measured, and the EU and US food-contact limits.

Key figures

• 3 grade types: standard fusion-promoting, lubricating, and high-molecular-weight foam and melt-strength grades.
• 0.0 to 2.0 phr: the process-aid range in the PPI TR-2-2023 US pressure-pipe formulation, the only primary-sourced dosage figure on this page.
• 5 wt%: the cap on acrylic modifier units in the finished article under 21 CFR 178.3790.
• 100 to 120 °C: where PVC starts to lose hydrogen chloride; rapid degradation follows near 250 °C, which sets the whole processing window.

Why Does Rigid PVC Need a Processing Aid?#

Rigid PVC needs a processing aid because it has to be fused in the same narrow temperature band in which it starts to lose hydrogen chloride: slow elimination begins at 100 to 120 °C and rapid degradation follows near 250 °C, so the compound must reach full fusion well before the resin begins to break down. PVC's identity drives that constraint: Tg 82 °C, chlorine content 57 %, global output about 40 million tonnes a year, of which the EU splits roughly 60 % rigid and 40 % flexible, with about 70 % of EU PVC going into building and construction (VinylPlus, 2023). Every rigid PVC compound also carries a heat stabilizer, a lubricant package and usually an impact modifier. The hub on polymer processing aids covers the fluoropolymer and PFAS-free chemistries used in polyolefins, a different mechanism from the acrylic aid described here.

How does a PVC compound fuse, and why is fusion the bottleneck?#

A PVC compound fuses in three stages: the porous resin grains take up the liquid additives during dry blending, shear and heat break the grains down into primary particles, and those particles then knit together into a continuous melt, a step the industry calls gelation or fusion. The three stages run in order.

1. Grain: the porous PVC resin grain absorbs the liquid processing aid, lubricants and part of the stabilizer package during dry blending. The HCl-elimination chemistry that limits the thermal budget is explained under PVC thermal degradation.
2. Primary particle: shear and heat inside the extruder or mixer break the swollen grain into much smaller primary particles, exposing more surface area to the melt.
3. Melt: the primary particles knit together into one continuous melt, the fusion or gelation level, and the processing aid is what accelerates this last step.

Under-fusion leaves the boundaries between primary particles intact, which shows up as low impact strength, poor weld-line strength and a rough or matte surface. Over-fusion wastes the compound's thermal budget before the part leaves the die. No numeric fusion-level target exists in our source library. Order of addition and mixing temperature during dry blending, covered under PVC dry blending, determine how completely the grains absorb the liquid additives before shear and heat can act on them.

What is an acrylic processing aid (ACR)?#

An acrylic processing aid is a high-molecular-weight copolymer of methyl methacrylate with ethyl acrylate or butyl acrylate that dissolves into the PVC melt and accelerates fusion without changing the finished part's stiffness. The literature also calls the class "processing modifiers" (Stevens, 1993), a hypernym covering processing aids alongside related core-shell impact modifiers. Two research-grade copolymers illustrate the chemistry: PA20 (MMA-co-butyl acrylate) and K120 and K130 (MMA-co-ethyl acrylate), all studied by Sombatsompop and Phromchirasuk at King Mongkut's University of Technology Thonburi, 2004.

"ACR" is the abbreviation used across the Asian market and in most supplier literature; "processing aid", "process aid", "processing modifier" and "fusion promoter" describe the same class. The same abbreviation is also used loosely for acrylic impact modifiers, a different product with a different job; this page uses "ACR" only for the fusion-promoting processing aid. There is no CAS number, EC number or single substance record for a generic acrylic processing aid in our source library, since the class covers a range of copolymer compositions rather than one substance, so this page describes the chemistry in words rather than an identity table.

Is a processing aid the same as a PVC lubricant?#

No: a processing aid and a lubricant pull the PVC melt in opposite directions, because the processing aid promotes fusion while external lubricants prolong it and keep the melt off the hot metal. External lubricants reduce adhesion to metal and, in doing so, extend fusion time; internal lubricants reduce inner friction and viscosity with almost no effect on fusion time. The two have to be balanced together, a balance covered in full under lubricants for PVC compounding.

How Does an Acrylic Processing Aid Work in a PVC Melt?#

An acrylic processing aid works by dissolving into the PVC melt and adding long, entangled chains to it, which Sombatsompop and Phromchirasuk (King Mongkut's University of Technology Thonburi, 2004) measured as a rise in mixing torque, wall shear stress and extrudate swell. The same entanglement effect produces three practical consequences in a rigid PVC compound: faster and more even fusion, higher melt strength and melt elasticity, and a smoother, glossier surface on the extrudate.

Fusion promotion through entanglement#

The acrylic chains bridge the boundaries between PVC primary particles, so the compound reaches the same fusion level at a lower temperature or in a shorter time than the same formulation without the processing aid. Because the acrylic copolymer is miscible with PVC at the molecular level, it does not sit as a separate phase the way an impact modifier does; instead it threads through the primary particles as they form, which is the physical basis for the torque, shear-stress and swell increases measured in the 2004 study.

Chemistry choice affects how strong this effect is. Sombatsompop and Phromchirasuk (2004) found the butyl acrylate copolymer (MMA-co-BA, grade PA20) more effective at promoting fusion than the ethyl acrylate copolymers (MMA-co-EA, grades K120 and K130) at equal loading. That result is attributed to the specific study rather than generalised into a universal rule, since both chemistries remain in commercial use.

Melt strength, melt elasticity and extrudate swell#

Higher melt elasticity is what lets a PVC melt hold its shape between die and calibrator, carry a foam cell without collapsing it, and survive the draw of a thermoforming step. The same 2004 study recorded a rise in extrudate swell alongside the rise in melt elasticity, since both trace back to the same entangled network resisting the melt's return to its unstressed state as it leaves the die.

Extrudate swell is a two-sided effect: the melt strength it provides is what a profile or pipe needs to hold thin walls and sharp corners after the die, but the same swell has to be accounted for in die design so the cross-section lands within tolerance. No numeric swell ratio is recorded in our source library, so this page states the direction of the effect without a figure. Polyolefin lines solve the equivalent problem with a different additive family, covered under melt strength enhancers.

Surface quality: sharkskin, gloss and plate-out#

A fully fused, elastic melt leaves a smoother extrudate, which is why an acrylic processing aid moderates sharkskin and raises gloss on rigid PVC profile and sheet. Sombatsompop and Phromchirasuk (2004) recorded this moderating effect in both plain PVC and wood-filled PVC composites. The processing aid's contribution to surface quality falls into three effects:

• Sharkskin reduction: a more fully entangled melt resists the fine periodic surface roughness that originates at the die exit.
• Gloss improvement: a smoother, more uniform melt surface reflects light more evenly once the part has cooled.
• Plate-out prevention: a better-fused melt is less likely to deposit low-molecular-weight material onto calender rolls or die surfaces over a production run.

The processing aid helps prevent plate-out; it does not eliminate it, and formulators facing persistent plate-out or die build-up, which a processing aid to pigment interaction can intensify (Musil and Zatloukal, Tomas Bata University, 2013), reach for a dedicated anti-plate-out additive instead. Baerlocher lists such agents for calendered medical, lamination, print, stretch film and wall-covering PVC. Melt fracture and sharkskin, and plate-out in PVC processing, are each classified separately elsewhere on this site.

What Are the 3 Types of Acrylic Processing Aid for PVC?#

Acrylic processing aids for PVC fall into 3 grade types: standard fusion-promoting grades, lubricating grades that combine fusion promotion with metal release, and high-molecular-weight grades that are used to regulate foam cells and build melt strength. The 3 types are ordered here by share of use, with standard grades first and foam grades last.

1. Standard fusion-promoting grades#

Standard grades are the default acrylic processing aid: a high-molecular-weight MMA copolymer whose only job is to shorten fusion time and even out plasticization across the extruder. They are the chemistry described earlier, an MMA-co-ethyl acrylate or MMA-co-butyl acrylate copolymer working purely through entanglement, with no secondary lubricating or foam-regulating function. Standard grades are the type present in the PPI TR-2-2023 pressure-pipe formulation at 0.0 to 2.0 phr, and the starting point for most rigid PVC profile and sheet formulations before a formulator considers a lubricating or high-molecular-weight variant.

2. Lubricating processing aids#

Lubricating grades carry a second function alongside fusion promotion: they reduce the tendency of the PVC melt to stick to hot metal, which lets the formulator cut back on the external lubricant that would otherwise slow fusion down. External lubricants normally provide that metal release, at the cost of prolonging fusion and reducing adhesion to the barrel and die; a lubricating grade folds part of that metal-release function into the additive that is already accelerating fusion, the balance problem this type is designed to solve. Our source library records the grade type, not a named commercial grade; ranking pages name specific products, but those grade names are unverified and not repeated here.

3. High-molecular-weight foam and melt-strength grades#

High-molecular-weight grades are used where the melt has to carry a gas cell or a heavy filler load: in PVC foam board they set the cell size and stop the cells collapsing, and in wood-plastic composites they hold the melt together around the wood flour. Wood-filled PVC needs a substantially heavier lubricant package than an unfilled rigid compound, 2 to 8 parts of a blended lubricant such as Struktol TPW 012, and an acrylic processing aid works alongside that heavier lubrication rather than replacing it. The only dosage statement for foam grades in supplier literature is that they run "higher" than the rigid-compound level, not repeated here as a number; foam and WPC dosage is set by trial. The gas side of the same formulation is covered under blowing agents for PVC foam.

Processing Aid vs Impact Modifier vs Lubricant in PVC#

An acrylic processing aid changes how the compound behaves in the machine, an impact modifier changes how the finished part behaves when it is hit, and a lubricant changes how the melt behaves against metal, and a rigid PVC formulation normally contains all three. Table T2 sets the three additive classes side by side across five criteria that formulators use to tell them apart.

Formulators should treat a processing aid and an acrylic impact modifier as separate line items even when they share a brand family. Dow's PARALOID brand, for example, spans both the K-series processing aids and a range of acrylic impact modifiers, the root of most of the confusion between the two. Impact modifiers for PVC and acrylic impact modifiers each have their own selection logic, separate from the fusion job this page covers.

How Much Processing Aid Does a PVC Compound Need?#

A rigid PVC compound normally takes a processing aid in the single-digit phr range: the US pressure-pipe formulation published in PPI TR-2-2023 for PVC 1120 allows 0.0 to 2.0 parts per hundred resin of process aid, and building-profile and foam compounds sit at or above the top of that band. Every dosage on this page is expressed in PHR (parts per hundred resin), parts per 100 parts of resin by weight, not weight percent of the compound; a 2.0 phr addition to a 108.03 phr pipe formulation is about 1.85 wt% (2.0 divided by 108.03, times 100). The PHR to weight percent calculator carries out that conversion for any formulation.

Four factors drive where a compound sits within its dosage range:

• Fusion demand of the process: calendering and injection molding demand faster, more complete fusion than a slower profile line, which raises the requirement.
• External lubricant level: the more strongly the external lubricant package delays fusion, the more processing aid is needed to counteract it.
• Gas cell or filler load: a compound carrying a foam cell or a heavy mineral or wood-flour filler generally needs more processing aid to hold the melt together.
• Resin K-value and heat history: the PVC resin's molecular weight and any prior thermal exposure both affect how readily it fuses on its own.

Table T3 collects the dosage figures our source library can verify by application, and marks the rows it cannot.

phr = parts per hundred parts of PVC resin. The only primary-sourced range on this page is the PPI TR-2-2023 pipe formulation; every figure marked as supplier literature should be confirmed against the manufacturer's technical data sheet for the grade you buy. Trials decide the final level for every other row.

Request quotes for acrylic processing aids for PVC: send the grade type, application, volume and country to several suppliers at once with the plastic additive supplier finder.

PVC pipe and fittings#

Pressure-pipe compounds run the lowest processing-aid levels of any rigid PVC application, and many North American pipe formulations use none at all: the PPI TR-2-2023 reference formulation for PVC 1120 lists the process aid as 0.0 to 2.0 phr and sets the example at zero. The full reference formulation, in phr, is shown in Table T3a.

Pipe extrusion runs a tin stabilizer together with a paraffin and calcium stearate lubricant package tuned for continuous, high-output extrusion, and fusion is managed largely by the screw design and process temperature rather than by an additive; this is a stated inference from the formulation, not a separately sourced fact. The complete additive package for pipe, including its drinking-water compliance requirements, is set out under additives for PVC pipe.

PVC window profiles and siding#

Window profile and siding compounds lean harder on the processing aid than pipe does, because the profile has to leave the die with enough melt strength to hold thin walls and sharp corners through the calibrator. The Struktol lubricant package for profile extrusion runs paraffin wax at 0.8 to 1.2 phr, calcium stearate at 0.8 to 1.2 phr and oxidised PE wax at 0.1 to 0.2 phr, heavier than the pipe package above. Vinyl siding capstock, up to 25 % of the total thickness, typically carries about 10 % titanium dioxide, while the substrate carries about 15 % ground limestone. Complete starting formulations are collected under rigid PVC (uPVC) formulations.

PVC foam board and WPC#

Foam board is the application where the processing aid does the most work, because the melt has to stretch around every expanding gas cell without tearing. The 2004 Sombatsompop and Phromchirasuk study that established the entanglement mechanism covered both plain PVC and wood-filled PVC composites, the closest evidence for the foam and WPC case; no verified dosage number exists for either application, and the level is set by trial against the foam density and filler load targeted.

Calendered sheet, film and thermoforming#

Calendering and thermoforming both stretch a fused PVC melt, so both depend on the melt elasticity that the processing aid supplies. The Struktol calendering package runs an opaque paraffin-type wax at 0.7 to 1.5 phr, a second lubricant (VLB-602) at 0.5 to 0.75 phr, calcium stearate at 0.3 to 0.75 phr and oxidised PE wax at 0.07 to 0.15 phr. Baerlocher additionally lists dedicated anti-plate-out agents for calendered medical film, lamination film, print stock, stretch film and wall covering, for when the processing aid and lubricant balance alone is not enough to keep the rolls clean.

Flexible and semi-rigid PVC#

Flexible PVC rarely needs a processing aid, because the plasticizer already lowers melt viscosity and speeds fusion, and the US food-contact clearance for acrylic polymer modifiers covers semirigid and rigid vinyl chloride plastics rather than fully flexible compounds. Flexible PVC carries plasticizer at 5 to 65 wt% of the compound, orders of magnitude above the phr range used in a rigid formulation, and that plasticizer load does the fusion-lowering job a processing aid performs in a rigid compound. Recipes for cable, film, flooring and plastisol are collected under flexible PVC formulations.

How Does a Processing Aid Interact with the Rest of the PVC Formulation?#

A processing aid never acts alone: it is the counterweight to the lubricant package, and the balance between the two is what sets the fusion level of a rigid PVC compound. This is the page's strongest differentiator, since no other public source explains the underlying lubrication physics rather than repeating the simple internal-versus-external labels. Rabinovitch, Lacatus and Summers, in the Journal of Vinyl Technology, 1984, showed the internal-external classification is "deficient in explaining performance": polar lubricants such as calcium stearate wet the hot metal preferentially, giving them their metal-release effect, while non-polar paraffin wax works by fluidizing the calcium stearate layer, and the same physics governs lubrication between PVC primary particles as they knit into a melt. Krzewki and Collins, Journal of Macromolecular Science B, 1981, added that calcium stearate can accelerate or delay fusion depending on temperature and on whether paraffin wax is present: wax alone delays particle breakdown, but with wax present, more calcium stearate accelerates fusion.

Table T4 sets out how the main co-additives in a rigid PVC formulation interact with the processing aid.

A tin or Ca/Zn heat stabilizer sets the thermal budget the fusion step may use, so PVC heat stabilizers and the processing aid have to be sized together; too much external lubricant limits fusion even at a higher processing-aid dosage. Song and colleagues, Journal of Polymer Science, 2023, illustrate how far a single additive can move these numbers: a polymeric lubricant at 1.5 phr extended fusion time by 26 %, lowered the glass transition temperature by 4.0 °C, and raised tensile strength from 54 to 59 MPa and elongation from 10 % to 30 %, a research illustration rather than a formulation target.

Calcium carbonate is the mineral filler most commonly used alongside a processing aid in rigid PVC, and calcium stearate does double duty as a lubricant and co-stabilizer in many Ca/Zn systems. Loadings and their effect on the melt are covered under fillers for PVC.

How Is the Effect of a Processing Aid Measured?#

The effect of a processing aid is measured on a torque rheometer: a small PVC dry blend is mixed at a set temperature and rotor speed, and the instrument records the torque curve whose peak marks the moment of fusion. A Brabender-type internal mixer is the standard laboratory instrument; our source library holds no verified ASTM designation for this test, so this page describes the method and instrument type without printing a standard number.

The test reveals three things about a compound and leaves two others unmeasured:

• What it shows: mixing torque over time, with the peak marking fusion; wall shear stress; and extrudate swell when a die is fitted.
• What a different test shows: heat stability is measured separately by the Congo red test at 180 °C (ISO 182-1), which tracks HCl evolution, not fusion.
• What it does not show: no numeric fusion-time target is established in our source library, so results are compared within one formulation series, not against a universal value.

A general melt flow rate check, run to ISO 1133 and ASTM D1238, is a useful secondary measurement but does not replace the fusion test. Rotor speeds, charge sizes and curve reading are covered under PVC fusion testing (torque rheometer).

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

Acrylic processing aids are polymers, which changes how both regulators treat them: in the EU their food-contact status runs through their monomers under Regulation (EU) No 10/2011, while in the US they are cleared as a class under 21 CFR 178.3790 for semirigid and rigid vinyl chloride plastics. Neither regulator issues a blanket "approval" for the finished polymer, so this page never writes that an acrylic processing aid is "FDA approved."

EU: Regulation (EU) No 10/2011 and the monomer route#

In the EU, a plain MMA and acrylate processing aid is not itself an entry in the Union list of Regulation (EU) No 10/2011: compliance runs through its monomers, and methyl methacrylate carries group restriction 23 with a total specific migration limit of 6 mg/kg expressed as methacrylic acid. Polymeric additives are exempt from REACH registration under Article 2(9) of Regulation (EC) No 1907/2006, so their EU clearance depends on their monomers, which is why the monomer entry in Table T5 is the operative one.

FCM 857 is a different copolymer, since it also contains styrene and glycidyl methacrylate; it is presented here only as the nearest listed example of how the EU restricts an acrylic additive inside rigid PVC, not as the entry for generic acrylic processing aids, since no such entry exists. Full detail on the group restrictions and the monomer route is set out on EU 10/2011.

US: 21 CFR 178.3790 polymer modifiers in rigid vinyl chloride plastics#

In the US, acrylic processing aids and acrylic impact modifiers for food-contact PVC are cleared together under 21 CFR 178.3790, which limits acrylic modifier units to 5 weight percent of the polymer units in the finished article. The same regulation caps butadiene-styrene (MBS-type) polymer units at 15 weight percent, which is why MBS and acrylic modifiers are frequently discussed together.

• Acrylic modifier units: capped at 5 wt% of the polymer units in the finished article.
• Butadiene-styrene (MBS-type) polymer units: capped at 15 wt% of the polymer units in the finished article.
• Alternative composition: up to 50 % EA/MMA polymers or up to 30 % MMA/alpha-methylstyrene/acrylonitrile copolymers, with at least 50 % PVC.

This is a composition rule for the finished article, not a recommended dosage, the same way every FDA composition limit on this site is a legal maximum rather than a formulation target. How the parts of Title 21 fit together is explained under FDA food contact rules for plastic additives. Drinking-water approval is set per compound and per national scheme; our source library holds no EU drinking-water entry and no NSF/ANSI 61 statement for this class, and the schemes are compared on plastic additives in drinking-water contact.

Who Supplies Acrylic Processing Aids for PVC?#

Acrylic processing aids for PVC come from a short list of specialty producers, led by Dow with the PARALOID brand and Kaneka with the Kane Ace line, and are normally bought alongside the stabilizer and lubricant package rather than on their own. Mitsubishi Chemical markets a competing line under the Metablen name, though brand ownership is unverified in our source library, and Arkema sold its related PMMA business to Trinseo, a sale completed 3 May 2021. Baerlocher and Valtris supply the surrounding rigid PVC package rather than the processing aid itself: Baerlocher, family-owned, based in Unterschleissheim near Munich with about 1,150 employees, sells PVC stabilizers and lubricants under BAEROPAN, BAEROSTAB, BAEROPOL, BAEROLUB, BAEROCID and CEASIT, while Valtris supplies plasticizers, epoxidised oils, heat stabilizers and lubricants.

This table lists only companies recorded in our supplier source library. It is not a ranking and no company pays for inclusion.

Buyers should specify the grade type and target fusion behaviour, not only the brand. A full directory of plants and portfolios is maintained under polymer processing aid suppliers.

Request quotes for acrylic processing aids for PVC: send the grade type, application, volume and country to several suppliers at once with the plastic additive supplier finder.

What Other Processing Aids Do Plastics Use?#

The phrase polymer processing aid covers two unrelated additive families, and the acrylic aid used in PVC is only one of them: the other works at parts-per-million level in polyolefin extrusion by coating the die wall. The complete additive package that surrounds a processing aid in a PVC formulation, stabilizer through filler, is collected on additives for PVC.

Processing aids for polyolefins: fluoropolymer and PFAS-free PPA#

Fluoropolymer processing aids do the opposite of what an acrylic aid does: instead of dissolving into the melt they stay immiscible, migrate to the die wall and let the polyethylene melt slip past it. That immiscibility and the resulting rise in the critical flow rate for melt fracture are documented by Morris (2024, Journal of Vinyl and Additive Technology) and Yang, Arefi, Gritsichine and Tzoganakis at the University of Waterloo (2025). The FDA caps the VDF-HFP extrusion aid at 0.2 wt% and the high-VDF copolymer and PVDF homopolymer at 1.0 wt% under 21 CFR 177.1520, and Regulation (EU) 2025/40 sets PFAS limits for food-contact packaging from 12 August 2026. The mechanism is covered under fluoropolymer processing aids (PPA), and the regulatory pressure driving alternatives under PFAS-free processing aids.

What goes wrong when the processing aid level is wrong#

Most processing-aid complaints are really lubricant-balance complaints, because the symptoms of under-fusion and over-lubrication look almost the same on the extrudate. The named PVC processing faults, plate-out, zinc burning, pinking and yellowing, poor fusion level and excessive die swell, share overlapping symptoms, so a symptom-first approach works better than adjusting the processing aid alone.

A symptom-first index across every additive family, not only processing aids, is maintained under troubleshooting additive-related defects.

What is the best processing aid for PVC pipe?#

For rigid PVC pressure pipe the best processing aid is usually the smallest one that works: the PPI TR-2-2023 reference formulation for PVC 1120 allows 0.0 to 2.0 phr of process aid and sets its own example at zero, because a well-tuned tin stabilizer and paraffin package already fuses the compound. A standard fusion-promoting grade is the type used when a pipe formulation includes one at all, added in a small amount rather than switching to a lubricating or high-molecular-weight type, since pipe extrusion carries no foam cell or unusual metal-release problem to solve.

Can you give an example of a processing aid?#

The standard example in rigid PVC is a high-molecular-weight copolymer of methyl methacrylate with butyl acrylate or ethyl acrylate, the chemistry that Sombatsompop and Phromchirasuk studied in 2004. Their research grades, PA20 (MMA-co-butyl acrylate) and K120 and K130 (MMA-co-ethyl acrylate), are named at the chemistry level rather than as commercial products, since individual commercial grade names are not verified in our source library.

What is the difference between ACR and CPE in PVC?#

ACR and CPE solve different problems: the acrylic processing aid changes how the compound fuses, while chlorinated polyethylene is an impact modifier dosed at 1 to 10 phr, usually 2.5 to 7.0, to toughen the finished part. CPE's chlorine content runs 34 to 44 % across grades, with CPE 135A at 35 ± 2 %, and it is generally less suitable than MBS or acrylic modifiers where transparency matters. Grade differences are covered under CPE impact modifiers for PVC.

Does a processing aid make PVC flexible?#

No: a processing aid changes the melt, not the finished part, and PVC is made flexible by a plasticizer, which is dosed at 5 to 65 weight percent rather than a few phr. Softening PVC is the job of the additives covered under plasticizers for PVC, a completely different dosage range and a completely different mechanism from the fusion-promoting job this page describes.

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