Maturity of Hansen Solubility Parameters (HSP) Usage in Different Applications

TAGS:  Science-based Formulation    

HSP holds the promise to speed-up formulation development in every application where ingredient compatibility is a must. Based on science, you can avoid unfocused trials and directly work with combinations that have a chance to give a result.

For the past 3-4 years, HSP has gained renewed traction due to an overall focus on bringing more science and calculation power (sometimes artificial intelligence but not only) into formulations.

Yet, even if, in theory, it can work everywhere; in practice, you need the right data and you need to know where you can best leverage this predictive tool.

Hansen Solubility Parameters (HSP) have been around for more than 50 years and have found their initial playing field mostly in the field of solvents, solvent blends and polymer-solvent compatibility. Beyond these native applications, there are many fields on the rise, with varying maturity levels.

Here is a mapping of the tool maturity per application to help you see if you can gain a competitive advantage straight away or in the near future. (It may be worth for you to invest in the generation of the right HSP data!) This mapping is based on the best of our knowledge today. Please help us enrich it by sharing your views. Answer the quick 5 questions to express your opinion and experience on HSP.

Before we continue with the maturity mapping, let us remind you that you can track what is happening in this field by subscribing to weekly updates on Science-based Formulation Channel!

Also, if you are new to this field or need a refresher, we recommend you to first watch first the following Tutorial series by SpecialChem’s Partner VLCI!

Let's look at the different applications across different formulation domains, the anticipated impact of HSP, the adoption rate of HSP and the data availability.

Mapping the Use of HSP for Every Application

There are many applications for HSP in formulations (HSP of skin in cosmetics, oil field extraction chemicals, barrier effects in plastics, fragrances, polymer blend, etc.). Here we focused on a selected number of cases that seemed to be of particular interest to SpecialChem’s community.

	Domain	Adoption Rate of HSP & Data Availabilty	Used in Cases
Pigments-dispersants	Coatings	HSP based Patents on some dispersant technology. Specific work on carbon black, notoriously difficult to disperse.  Limited use in coatings formulation due to lack of HSP data for pigments and dispersants representing several thousand products.	Find the most efficient dispersant that will minimize pigment usage.
Solvent replacement	Coatings, Adhesives	Multiple HSP based solvent recommendation by Solvay, Eastman and some research institutes (e.g. Sussol).   HSP data available on many supplier Technical data sheets. 500 commercial products covered. Good adoption rate of HSP and HSPiP software.	Identify most probable solvent or solvent blend with more desirable tox and ecotox profile.
Binder-solvents	Coatings, Adhesives	HSP data available on supplier Technical data sheets for solvents and some in literature for generic binders.  Good adoption rate of HSP and HSPiP software.	Optimize film forming properties of solvent-borne coatings.
WB binders-coalescent	Coatings, Adhesives	HSP data available on supplier Technical data sheets for coalescents and some in literature for generic binders.	Optimize film forming properties of waterborne coatings.
Diluents / monomers	Reactive systems (UV Cure, 2K Systems, Reactive Adhesives)	Isolated cases of HSP data on technical data sheets.  Used at research level for polymer design and co-monomer selection.	Increase compatibility between monomers, oligomers and crosslinkers.
Active-emollient/oil	Cosmetics	“Formulating for efficacy” software available with HSP for around 100 ingredients.  Data available on some natural oils.	Increase activity of the ingredient in the formulation, reduce dosage. Creatively formulate with natural oils adapted to active ingredient.
Surfactant-oil	Cosmetics	Some patents by Unilever to reduce skin damage by optimizing surfactant/oil combinations.  Use of HLD as a complementary tool to predict stability. Suppliers like STEPAN and SEPPIC use the data to help formulators adopt their new surfactants.	Compatibility of bio-based surfactants and natural oils to create distinctive natural formulations.
UV Filters / oil	Cosmetics	Historical use of HSP to optimize the cost and the concentration of organic, UV filters.  Patents by L’Oreal.  No HSP on UV filter datasheets.	Maximize compatibility of UV Filter and solubilizer to minimize concentration of under scrutiny organic UV filters.
Plasticizers / Binders / Polymers	PVC compounds, Adhesives, Inks	Historically used to identify most suitable plasticizer for given PVC resins in compounding and coatings.  Though the principle of resin/plasticizer selection is similar to solvents, little data available.  Similar situation with process oils (Nynas) for inks and adhesives, and for hydrocarbon resins and rubbers (Novares®).	When new polymers are being introduced, such as PLA, HSP are used to select compatible plasticizers.
Resins / Tackifiers	Adhesives	No data available on data sheets of suppliers. Some elements in patents.	Use to measure compatibility of block-copoylmers and tackifiers. For example, in Pressure sensitive adhesives.

We are seeing more and more traction about HSP driven by several factors:

• Desire of formulators to do less trial/test/error related to compatibility and stability. Using more predictive calculation power they aim to reduce the number of tests actually performed and gain speed in formulation development.
• Major trend with large formulators to both centralize and digitize product and formulation data. This is part of digital transformation of companies who want more and more reliability and traceability. This topic goes beyond HSP and covers data sheets, product information, formulation documentation, transformation modelization, using calculation models to predict properties based on chemical structure…
• Raw materials who want to speed up adoption of their new chemistries, making HSP of their products and relevant co-ingredients available. This data could be more usable than generic starting formulations.