Grease-Resistant Barrier Coatings for Foodservice Packaging: Designing for Performance Without PFAS

Introduction

The RFP on your desk is contradicting itself.

Your downstream customer has made clear that the packaging must be PFAS-free. Pressure from accumulating health and safety concerns about “forever chemicals,” brand sustainability commitments, state-level bans, and forthcoming regulation expected to restrict the recyclability of PFAS-treated papers has made that requirement non-negotiable. The recyclability angle matters because it is a core part of brand owners’ sustainability story, and PFAS in the fiber stream undermines it. Further down the same spec sheet, the grease resistance requirement still lands on a KIT score of 12, sometimes higher, measured on a flat test sheet. Those two requirements were never designed to coexist. The testing protocol that defines acceptable grease resistance for most foodservice applications was built around the chemistry your customer is now asking you to eliminate.

This is not a marginal complaint. It shapes nearly every PFAS replacement program that crosses our desk. Formulators are being asked to deliver performance against a standard that was built to measure something else, on a surface that will never exist in the finished package, for a chemistry mechanism that behaves fundamentally differently from the one being replaced.

The real-world condition is not what KIT tests. Hot food packaging holds product at temperatures around 170°F for twenty minutes or more during delivery and service. It gets folded, scored, and creased during converting. It rides in a delivery bag that is warm and humid. The test that matters is the one that matches how the package actually fails.

This article walks through how we think about designing PFAS-free grease resistance into foodservice packaging at Mallard Creek Polymers: the four trade-offs that shape every formulation decision, why KIT is increasingly being replaced for film-based barriers, and what application-matched validation looks like in practice.

Why PFAS-Free Grease Resistance Is a Different Design Problem

Fluorochemistry made oil and grease resistance look simpler than it actually is, because what fluorochemistry did was not actually coating.

PFAS treatments were applied at the paper mill through a saturation process that pushed the chemistry into the fiber network itself. Every individual fiber was treated. There was no film on the surface and no coat weight to manage, because there was no coating in the conventional sense. Each fiber became individually grease-repellent through surface-energy chemistry, and the resulting packages were nearly bullet-proof against grease penetration. The KIT test, developed during this era, was designed to measure that surface-energy behavior efficiently. Minor process variations rarely broke performance because the protection was distributed throughout the substrate, not concentrated in one continuous film.

PFAS-free coatings achieve grease resistance through a fundamentally different mechanism: continuous, dense film formation that physically blocks oil from entering the substrate. The polymer does the work, and the polymer has to form a complete, defect-free film across a porous paper or paperboard surface to do it. That film also has to survive everything that happens to the package after it leaves the coater: folding, scoring, abrasion, heat, moisture, and time.

That shift changes which variables matter. Substrate porosity and holdout, film continuity at the micro level, coating weight, drying profile, and crosslinking all move from secondary considerations to critical determinants of whether the coating works. The same flat-pack carton that PFAS protected at the fiber level now has a coating sitting on its surface that has to bend around every fold without fracturing.

Programs that treat PFAS replacement as a drop-in substitution, where the new polymer simply takes the place of the fluorochemical treatment without redesigning the rest of the system, tend to produce trials that look promising on a flat sheet and fail at scale or in the field. The mental model needs to change alongside the chemistry.

Four Trade-Offs That Shape Your PFAS-Free Grease-Resistance Design

Designing PFAS-free grease resistance is a constraint-satisfaction problem, not an optimization one. Formulators almost never get to maximize grease resistance in isolation. The following four trade-offs show up in nearly every foodservice coating program we work on.

1. Grease Resistance vs. Recyclability and Compostability

The polymer properties that drive strong oil and grease performance interact with end-of-life outcomes in ways that surprise formulators evaluating their options for the first time. Done right, that interaction can be a competitive advantage. Done badly, it forces the brand owner into a sustainability story they cannot defend.

Recyclability is where latex-based PFAS-free coatings genuinely excel. High-barrier packaging applications generally require high water and water vapor barrier performance, which makes most coated packaging incompatible with industrial composting regardless of chemistry. But the same applications often have a strong path through paper recycling, and this is where latex polymers outperform extruded polymer alternatives. Low coat weights and the way latex films fracture and separate from fiber during repulping makes them substantially easier to recover in the recycle stream than extruded films. For a brand owner committed to a recyclable end-of-life pathway, that is a meaningful advantage, and one worth designing for from the start.

Compostability is a different conversation entirely. The compostable packaging market is largely served, often imperfectly, by biopolymer solutions such as starch, PLA, and PHA. These systems handle low-barrier requirements adequately but struggle with the water resistance and barrier durability that more demanding applications require. Latex-based coatings, including PFAS-free latex coatings, are not designed to produce compostable packaging in any meaningful certified sense. Formulators evaluating compostability as a primary end-of-life requirement should be working in the biopolymer category, or examining emerging biopolymer-latex hybrid approaches, rather than selecting a pure latex barrier coating.

The practical implication is that the brand owner’s committed end-of-life pathway should drive the conversation before chemistry selection begins. A recyclable target opens a wide and capable design space for latex-based PFAS-free coatings, with real performance and meaningful differentiation against extruded alternatives. A compostable target points the formulator toward a different polymer category entirely, and the realistic performance ceiling there is lower than many brand owners expect.

2. Coating Weight vs. Fold-Crack and Blocking Performance

Heavier films tend to pass flat-sheet grease tests more reliably. Flat-sheet performance is not what determines whether foodservice packaging works.

Most foodservice packaging does not live on a flat sheet. Paperboard takeout containers, hot food clamshells, molded pulp trays, hot entrée cartons, and similar formats ship flat-pack from the converter and are folded, scored, creased, or assembled before or at the point of use. The coating that holds up perfectly on the flat test sheet has to survive the bend radius at every corner and score line.

This is where PFAS-free programs often break. A coating designed for peak flat-sheet grease resistance, achieved through heavier coat weight or tighter film morphology, can fracture at the fold line. The coating holds everywhere except the corners of the carton that actually contain the food.

What the best PFAS-free OGR latex films actually deliver is a balance: oil and grease resistance, film flexibility for converting durability, and blocking resistance so that coated rolls and stacked cartons store without sticking together. Optimizing any one of these without the others tends to produce trials that pass an isolated test and fail in production. Polymer design (film flexibility, elongation behavior, particle morphology, crosslinking strategy) often does more useful work than increasing coating weight. Coating weight has a ceiling beyond which added grease resistance comes at the cost of fold-crack performance, blocking, or recyclability.

This three-way balance is what our technical team spends most of its time optimizing for specific applications. Tykote® 6161 is an example of an OGR-focused chemistry designed with converting durability in view. Matching the right grade to the specific application (oil or food type, contact temperature, converting method, end-of-life pathway) is part of what we work through with formulators during technical conversations.

3. Grease Resistance vs. Water and Moisture Vapor Barrier

Formulators sometimes assume grease resistance and water resistance travel together. They rarely do.

Grease resistance, water absorption (Cobb), and moisture vapor transmission rate (WVTR) pull on different polymer properties. A coating optimized for hot food contact can underperform on Cobb in applications with sauce, condensation, or moisture. A low-WVTR coating tuned for frozen or refrigerated packaging is rarely a strong grease performer without additional design work.

Balancing these targets in a single coating is genuinely difficult. Dedicated products are often required for specific performance combinations.

For applications where grease and water resistance need to coexist, Tykote® 6161 is designed to handle both. For applications where moisture vapor transmission is the primary constraint, such as frozen or humid storage, Tykote® 1004 and Tykote® 1014 are engineered for low WVTR performance.

Dual-barrier and triple-barrier targets that cannot be met by a single chemistry may push the design toward architecture change rather than chemistry change. That is where the single-layer versus multi-layer question becomes material.

4. Single-Layer vs. Multi-Layer Architecture

PFAS-free grease coatings sometimes cannot meet all performance targets within a single film without compromising recyclability, flexibility, or process efficiency. In a high-barrier packaging system, a multi-layer approach allows the formulator much wider ability to achieve competing performance goals than a single coating can.

Adding heat-sealability to the requirement list further complicates things. Heat-seal chemistry and grease-barrier chemistry rarely ask the same things of the same polymer, and reconciling them in a single film is often impractical. Multi-layer architecture handles this constraint set well, particularly for heat-sealable foodservice packaging.

For a deeper look at when to stay single-layer versus add a functional layer, see our analysis of single-layer versus multi-layer barrier strategies.

Why the KIT Test Is Increasingly Being Replaced for PFAS-Free Programs

The KIT test measures the ability of a treated surface to resist a defined series of oil-solvent mixtures for fifteen seconds at room temperature. It was developed when the dominant grease-resistant chemistry was fluorochemical, and it was designed to measure surface-energy-based repellency efficiently and repeatably for that chemistry.

For PFAS-free, film-based coatings, KIT serves a much narrower function. It is essentially a crack and pinhole finder. A passing KIT score tells you the coating film is continuous on a flat sheet at the moment of testing. It does not tell you how the coating performs at 170°F under twenty minutes of hot food contact. It does not tell you how the coating survives folding, scoring, or converting. It does not tell you whether the package will leak when delivered.

The industry has recognized this gap. TAPPI is concluding a six-year development effort on a more representative test for film-based grease barriers. The length of that effort is itself instructive. KIT’s value to producers is not just predictive accuracy. It is speed. Production facilities need fast results to determine whether a roll or reel of paper is in spec at the moment of manufacture. Any replacement test has to deliver KIT’s rapid turnaround while measuring something more meaningful for PFAS-free systems. That is a hard problem, and the time spent solving it reflects how seriously the industry is taking it.

MCP follows this work closely as the industry looks to identify the alternative standard test that will eventually replace KIT for film-based barrier coatings. The work is active and ongoing, and we expect the resulting protocol to materially change how PFAS-free programs are evaluated.

For formulators, the practical implication today is two-sided. KIT can give false passes, where a flat-sheet result does not translate to converted-package performance. It can also give misleading fails, where a film-based system is not designed to perform against KIT’s specific solvent challenge set but performs well in actual hot-grease contact. Neither result tells you what you need to know about the finished package.

Until the replacement test is finalized and adopted, formulators working on PFAS-free programs may want to consider supplementing KIT with tests that mirror actual use conditions. Hot-oil hold time at application temperature and realistic dwell duration captures time-temperature failure modes KIT does not. Post-converting barrier retention testing on creased or scored samples catches fold-crack failures. Finished-package stress testing under delivery-bag conditions captures failures that appear only in the field.

The guiding principle is straightforward: the test that matters is the one that mirrors how the package actually fails. Building the validation protocol around the application, not around the legacy standard, changes the entire trial process.

How Polymer Chemistry Choice Fits In

Polymer chemistry family narrows the design space. It does not determine the answer.

Acrylic emulsions are the most common starting point for PFAS-free grease resistance. They deliver highly oil-resistant, low-coat-weight barriers, along with optical clarity, broad regulatory compatibility, and attractive recyclability performance. That combination makes them a natural fit for hot food packaging, bakery liners, and food-contact topcoats where converting demands matter alongside barrier performance.

Styrene-acrylic polymers provide a balanced profile of oil and water barrier properties, handle pigment well, and tend to be cost-effective at scale. They are often useful in dual-barrier recyclable applications where a single coating has to do more than one thing.

Styrene-butadiene offers flexibility and low moisture vapor transmission. It is not typically the primary choice for grease-first applications, but it is relevant where fold-crack performance, frozen storage, or humid-environment durability also matter.

Within each chemistry family, the specific polymer design (particle size, Tg, functional monomers, crosslinking approach) and the formulation context it sits in (substrate, coating weight, drying profile, converting method, available coating application equipment) determine real-world performance. The chemistry choice is where the conversation starts, not where it ends.

Building a Validation Protocol That Matches Your Application

The failure mode in the field is the only test that truly matters. Everything else is a proxy for it.

The validation protocol that tells you whether your PFAS-free coating will work should be defined before trial formulation begins, not reverse-engineered after a trial fails. That protocol depends on application-specific inputs: oil or food type and viscosity, contact temperature, dwell time, converting method and fold geometry, available coating application methods at the paper producer or converter, end-of-life pathway, and applicable compliance framework (FDA, BfR, state-level PFAS regulation).

The most productive first conversation with a polymer partner is about that protocol, not about which product to request. Once the validation conditions are defined, sample selection becomes much more efficient. The formulator knows what to test against, the supplier knows what the coating has to do, and trial cycles do not waste time on samples that were never going to match the application.

This is how we work with formulators at Mallard Creek Polymers. The first technical conversation is about understanding what the package actually has to do, what has already been tried, and what the validation protocol needs to look like. Polymer selection follows from that, not the other way around.

Ready to build a validation protocol for your PFAS-free grease-resistance program?

The first conversation is about understanding your application, your converting process, and your end-of-life target. If you are early in PFAS replacement, or working through trial results that do not match expectations, that is the conversation worth having.

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Frequently Asked Questions

Can you achieve grease resistance without PFAS?
Yes. PFAS-free grease-resistant coatings are commercially viable today. They achieve performance through continuous, dense film formation rather than the fiber-level surface-energy treatment that fluorochemicals provided. Success depends on polymer chemistry, film continuity, coating weight, substrate interaction, and converting method rather than a single surface treatment.

Is the KIT test still relevant for PFAS-free coatings?
KIT remains widely specified, but for film-based PFAS-free coatings it functions primarily as a crack and pinhole detector rather than a true performance predictor. TAPPI is concluding a multi-year development effort on a replacement test designed for film-based barriers, and MCP is part of an industry consortium working on that effort. In the meantime, formulators should consider supplementing KIT with application-specific validation that reflects real use conditions.

What polymer chemistry is best for PFAS-free oil and grease resistance?
Acrylic emulsions are the most common starting point, offering highly oil-resistant low-coat-weight barriers, optical clarity, broad regulatory compatibility, and attractive recyclability performance. Styrene-acrylic systems work well where oil, water, and process cost matter together. The right choice depends on substrate, application temperature, end-of-life pathway, and competing performance targets.

Can PFAS-free grease-resistant coatings be both recyclable and compostable?
These two end-of-life pathways generally do not coexist in the same package. Latex-based PFAS-free coatings deliver strong recyclability, often outperforming extruded polymer alternatives because low coat weights and clean fiber separation during repulping make them easier to recover. Compostable packaging is a different category, typically served by biopolymers such as starch, PLA, and PHA, and the realistic barrier performance ceiling in that category is lower than many brand owners expect.

Why do my PFAS-free coatings fail at fold lines on converted packaging?
Fold-crack failure usually signals that the coating is optimized for flat-sheet barrier performance at the expense of film flexibility. The best-performing PFAS-free OGR latex films deliver a three-way balance of oil and grease resistance, flexibility, and blocking resistance. Optimizing only one of those three tends to produce trials that pass an isolated test and fail in production. MCP’s technical team works with formulators to optimize this balance for specific applications and converting methods.

What should I test if KIT alone is not enough?
Consider supplementing KIT with tests that match actual use conditions: hot-oil or hot-food hold time at application temperature and realistic dwell, post-converting barrier retention on creased or scored samples, and finished-package stress validation under delivery and storage conditions. Application-matched testing catches failure modes that flat-sheet KIT does not.