# Sun Care Film Formers

Topic radar · 381 documents · 2021-01-01–2026-10-10 · updated 2026-10-18

Canonical: https://slate.greyb.com/radar/sun-care-film-formers/innovations

## In one minute

### The film carries the claim, not the filter
Across the filings the UV filters are largely conventional, and the claimed number comes from the package around them. A mineral sunscreen reaches SPF of at least 30, a critical wavelength of at least 370 nm and 80-minute water resistance from a silica and silicone-copolymer system with no organic filter at all [1]. An organic system reaches SPF of at least 50 with the active capped at 15% and the acrylic film former at 2.5% [2]. A third sets SPF 50 to 110 by the weight ratio of film-forming polymer to silica [3]. The filter is an input; the film is the variable that sets the label.

1. [US2024307277A1](/?paper=US2024307277A1&utm_source=radar&utm_medium=dashboard)
2. [US12576017B2](/?paper=US12576017B2&utm_source=radar&utm_medium=dashboard)
3. [CN114727910A](/?paper=CN114727910A&utm_source=radar&utm_medium=dashboard)

### The public record is written about filters, claims and brands, and the film former surfaces mainly when a supplier is selling it
Read the coverage of this field and the subject is the filter list, the claim on the pack and the brand behind it. The film chemistry appears mostly as a product being marketed. A functionalized soy film former is covered as an ingredient that raises SPF and improves dispersion in emulsions, and a trade explainer groups film formers with emollients and rheology modifiers as the supporting ingredients that decide whether a formula succeeds. Outside the supplier shelf, the writing runs to filters, dosage forms, testing and litigation. The specific film systems the filings describe do not appear in it.


### The film former is becoming a product the brand buys
The clearest commitment in these documents is from the ingredient houses, and it is to the polymer rather than to a formulation. Nouryon has filed two film-forming polymers for alcohol-based sunscreens: a polyvinyl alcohol derivatised with acids or lactones to raise waterproofing, and a polyester built from renewable diacids and polyglycerols that dissolves in ethanol and tolerates dimethyl ether as a propellant. Elementis has filed a citric-acid polyester whose stated purpose is water resistance without microplastics. Dow and Rohm & Haas have built the same idea on a silylated polysaccharide, claimed across maltodextrin and cellulose. The market side has caught up: a nature-derived functionalised soy film former is being sold on SPF and dispersion in emulsions.


### A settled silicone toolkit
The same materials recur across routes that otherwise differ. Trimethylsiloxysilicate is the film former in a water-in-oil makeup base, in a synergistic oil-and-aqueous film-former pair, and in a long-wear composition built from a silicate crosspolymer, an acrylate/silicone copolymer and trimethylsiloxysilicate. An organically modified clay structures the oil phase in Shiseido's water-in-oil sunscreen and appears beside a methyl methacrylate crosspolymer in a Chinese water-repellent lotion. That repetition reads as a settled toolkit rather than a field still searching, and the materials are commodity: none is scarce and none is proprietary to a single supplier.


### The trade's own formulation guidance treats the excipient package as one of two levers
This is not only the filings' argument. A supplier-published formulation playbook tells manufacturers to work two levers: make the filter system more effective, and use specific excipients and formulation properties to hold and enhance protection. It frames this as the response to an uncertain filter future, which is the same pressure the filings answer. The trade press makes the companion point from the other side, that laboratory SPF and real-world protection diverge and the gap is a formulation problem.


### Two of the largest houses have committed to a water-continuous film
Shiseido's water-based oil-in-water technology is presented as holding high water resistance while adjusting the moisture on the skin surface as humidity changes. Kao has published a humidity-responsive film built from agar hydrogel capsules carrying UV absorber and a highly water-retaining polymer in the aqueous phase of an oil-in-water formulation, described as light and adaptive through the day. Both are company statements about their own technology rather than independent measurements, and both are argued on comfort rather than on filter chemistry.


### Claims written on measured properties, not named chemistry
Several filings claim a threshold rather than a molecule. A hydrophobic film former with surface tension below 35 dynes/cm, paired with hydrophobic particles, holds a water contact angle above 90° initially and at least 60° after 40 minutes; a related filing claims 130° or greater. A threshold on a measured property reaches polymers the applicant never tested, which makes the claim broader than a named chemistry and harder to design around. It also moves the freedom-to-operate question down a level, from which polymer is patented to what the finished film actually measures.


### The claim is contested, and the contest turns on proof rather than on chemistry
A class action alleging that a film-first sunscreen labelled SPF 40 tested at 23 for the face and 20 for the body was dismissed twice, both times for lack of standing. The court did not decide whether the SPF was right. It found the plaintiffs' testing of five bottles bought on a single day could not be linked to what they had bought, so no injury was pleaded.


## Overview


Executive summary


## Research

### The stabilizer and the film become one material
In a Pickering emulsion the particle at the oil-water boundary is the UV filter, so the filter and the emulsifier are the same material. Pola Kasei builds a surfactant-free oil-in-water system from fine titanium dioxide and a low-molecular-weight hydrophilic acrylic polymer that stabilizes the droplet and then co-deposits with the oxide as the film. An emulsifier-free lotion takes the other route: it phase-transforms from oil-in-water to water-in-oil on skin and forms the film in place. Where the roles stay separate they are still chosen together. A co-assembled film of polysiloxane-15, trimethylsiloxysilicate and a vinyl dimethicone/methicone silsesquioxane crosspolymer raised SPF by 61.58% and UVA protection by 43.84% against the same filter system without it, and the authors attribute the gain to structural similarity between the film formers and the powder. That is the mechanism measured independently of any applicant's own testing.


### The film is engineered against a defect it creates
Most of the sensory work is written against a problem the film former itself makes. A water-in-oil base holds its film former, emulsifier and crosspolymer at a set ratio specifically to remove the stickiness and roughness that high silicone loads leave behind. A long-wear composition balances a silicate crosspolymer, an acrylate/silicone copolymer and trimethylsiloxysilicate to hold twelve hours in the parts of the face that move without cracking. Conventional silica is named as the cause of cracking, and a biomimetic mesoporous silicon replaces it; a resin that bonds hydroxyl-bearing powder into its own backbone during synthesis targets powder settling, flaking and migration under sebum. More film former buys durability and costs comfort, so the work goes into the structure of the film rather than its quantity.


### Biobased film formers split into two bets
One bet is an engineered polymer. Dow and Rohm & Haas silylate maltodextrin into a vinylic-carbon-free film former, claimed for water resistance and as an SPF booster in alcohol-based sprays; the dextrose-equivalent window narrows from skin care to sun care to the booster claim, which suggests the boosting effect depends more sharply on chain length than plain film formation does. Chanel and Polymaris claim a fermentation-derived polyhydroxyalkanoate as the film former outright. The other bet is cheap and degradable by nature: botanical blends, and a bacterial cellulose suspension sold as a film-forming or SPF-enhancing agent. The engineered polymers carry the SPF-booster claim that changes a formula's economics; the botanicals protect a formula, not a position.


### A line that stops
The edible electrospun film was published in 2022 and granted in 2023, and nothing follows it. Even if it resumed it would be assessed as a food or food-contact material, not a sunscreen, so it cannot capture the SPF-booster economics pulling the rest of the field forward. It is the clearest signal of where the value is not.


## Market

### What is worth protecting is the formulation know-how, and it is being enforced as a trade secret
The most valuable thing in this field is not a molecule, and the courts have treated it that way. Kolmar Korea won a trade secret case against Intercos Korea over sunscreen technology, after a former employee moved and confidential documents went with them. The dispute was about formulation research and development, and the remedy came under trade secret law rather than patents.


### The filter list is moving on several fronts at once
Regulation is not the only thing changing the filter list. Bipartisan US legislation has been introduced to speed approval of ingredients already accepted elsewhere, aiming to align US standards with international practice. At the same time the agency has both added and removed actives: bemotrizinol was proposed in December 2025 and added in June 2026 with an exclusivity window for the first seller, while aminobenzoic acid and trolamine salicylate came off the monograph on safety grounds in September 2026.


### Biobased is now a sized and audited category rather than a claim
Two things have changed the standing of the biobased film former. It is being tracked as its own market segment, with bio-film formers for sun creams split by source, benefit and formulation type. And an environmental and ecotoxicity assessment now sits behind at least one biobased SPF booster, using a life-cycle method across the product's life.


### The venture money is going to new filters, not new films
The funded activity in this field is on the filter side. UVera, an H2020-backed biotech, is developing a natural UV filter positioned on safety for people and the environment. Roka Furadada raised more than EUR 8 million for photoprotective ingredients, taking over a line that a pharmaceutical company had abandoned. Lygg was founded to develop new sunscreen ingredients.


### The spray format carries its own legal exposure
The format filings argue on removing flammability, inhalation risk and volatile emissions. The legal record shows why that argument has force. Bayer and Beiersdorf settled a class action over Coppertone spray sunscreens for US$2.3 million, with the brand testing for benzene for at least eighteen months afterwards. Johnson & Johnson's recall of aerosol Neutrogena and Aveeno sunscreens over a cancer-causing chemical was consolidated into a multi-district proceeding covering at least sixteen actions.


## Strategy

### Retention is being built into the molecule instead of the film
The most direct alternative to a film former is to make the absorber itself stay. A filing from Hyprskn and the University of Colorado attaches an ortho-phthalaldehyde group that bonds covalently to lysine residues in the stratum corneum, holding the chromophore in the epidermis for days to weeks with no film holding it there. Rianlon reacts a UV absorber monomer into the film-forming polymer so the filter cannot migrate. A University of Arizona filing polymerises the absorber into a bridged polysilsesquioxane nanoparticle so it cannot leach, and Johnson & Johnson built a UV-absorbing polyether by ring-opening polymerisation and attached the chromophore afterwards.


### The economic claim is SPF boost, and it is written as a measurable specification
The claim that changes a formula's cost is not water resistance but more protection for less filter, and it is being filed as a number rather than a composition. BASF claims a citrate wax with no intrinsic UV protection that raises SPF and water resistance in formulations built on organic filters. Ewoo Bio's booster pairs hydrogenated synthetic hydrocarbons with medium-chain alkyl silicones to raise blocking efficiency at a lower filter load. Nippon Catalytic's acrylic additive is defined by particle size, glass transition temperature, log Kow and a swelling ratio measured after five hours of water immersion; Rohm & Haas's core-shell booster is defined by dry particle size and void content.


### Removal is being filed as a claimable property
The tenacity that wins the water-resistance claim creates the next problem, and one filer has made removal the invention. Naris states the trade-off outright, that high salt and water resistance normally produces a film ordinary cleansers cannot remove, and claims the combination that gives both, built on an oil-soluble film former with no silicone skeleton. Cosmecca claims water resistance and easy cleanability together at a polymer content of 0.1 to 0.25% and a film former at 0.4 to 0.6% by weight.


### Delivery format is where the remaining ground sits
If the film former is an input, differentiation moves to how the product is delivered, and that is where the recent filings cluster. A bag-on-valve compressed-air spray is argued on removing flammability, inhalation risk and VOC emissions while holding SPF 50+ and strong water resistance, and an emulsified setting spray is defined by being propellant-free. Around them sit an electrostatically sprayable formulation with a dielectric-constant window, a dual-phase water-and-oil spray whose two layers stay separate until shaken, and a spray combining photo- and pH-responsive microcapsules with a three-part film system.


## Areas

- Water Resistance & Durability · 92 documents
- SPF Efficacy & UV Boost · 90 documents
- Formulation & Processing Compatibility · 89 documents
- Sensory & Aesthetic Performance · 35 documents
- Sustainability & Biobased Platforms · 66 documents