Hydroligroin

HYDROLIGROIN™

Low environmental impact water-in-oil emulsion — the green alternative to pure ligroin

LCA verified: >30% reduction in overall environmental impact

What it is Hydroligroin™ is a water-in-oil (W/O) inverse emulsion of ligroin and water in equimolar ratio, stabilised with a proprietary low environmental impact surfactant system. Specifically developed for the professional cleaning of artworks and historic artefacts, it reduces the overall environmental impact — calculated through Life Cycle Assessment — by more than 30% compared to pure ligroin, while maintaining identical solvent effectiveness on nonpolar substances.

Why it matters Pure ligroin is one of the most widely used solvents in conservation — but it comes with high VOC emissions, strong odour, significant fire risk, and a heavy environmental footprint. Hydroligroin™ solves all of these problems in one product: same cleaning power, dramatically lower impact. Laboratory studies using gravimetric analysis and FTIR-ATR spectroscopy on non-porous and low-porosity substrates have confirmed that the system leaves no residue on the treated surface.

Key features

• Direct substitute for pure ligroin — no workflow changes needed

• 30% reduction in overall environmental impact (LCA verified, ReCiPe 2016 Midpoint H)

• 60% reduction in effective VOC emissions during use

• Flash point >40 °C — significantly reduced fire risk vs pure ligroin (<0 °C)
• No residue on treated surfaces (confirmed by FTIR-ATR and gravimetric analysis)
• ~35% reduction in solvent consumption per m²
• Dilutable with deionised water (up to 20%) for milder action
• Equivalent selectivity towards nonpolar substances (Hansen RED <1)

How it works

Application phase: The emulsion is applied with a cotton swab. The ligroin, compartmentalised within the inverse micelles, is selectively released upon contact with the nonpolar layer to be removed (varnish, wax, lipophilic deposits).

Action phase: The ligroin dissolves and mobilises the nonpolar soiling, while the aqueous phase — due to its affinity with the hydroxyl groups of cotton cellulose — remains preferentially absorbed within the swab.

Removal phase: The swab captures the solubilised soiling residues. Complete evaporation of the system leaves no residue on the treated surface.

Applications

• Removal of aged oil varnishes from canvas and panel paintings
• Removal of natural and synthetic waxes from stone and painted surfaces
• Degreasing of lipophilic deposits from various substrates
• Cleaning of greasy particulate deposits from heritage materials

How to use

Preparation: Shake the bottle before use to ensure emulsion homogeneity. For milder action, dilute with deionised water up to 20% while maintaining stability.

Application: Soak a cotton swab with Hydroligroin™. Apply with gentle circular movements on the surface.

Removal: Wipe with a clean, dry cotton swab.

Important: Always perform a preliminary test on an inconspicuous area. Do not apply on water-sensitive surfaces without prior assessment (e.g., lean tempera, unprotected watercolours).

Environmental profile — Life Cycle Assessment

LCA analysis (cradle-to-gate, Ecoinvent 3.10, ReCiPe 2016 Midpoint H) per functional unit: cleaning of 1 m² of painted surface.

• Climate change (kg CO₂ eq): −28% vs pure ligroin
• Human toxicity, non-cancer: −35%
• Photochemical ozone formation: −62%
• Fossil resource depletion: −32%
• Particulate matter formation: −41%

Advantages over pure ligroin

• Overall LCA impact: <70% of pure ligroin
• VOC emissions during use: reduced >60%
• Odour during application: significantly reduced
• Fire risk: reduced (flash point >40 °C vs <0 °C)
• Solvent consumption per m²: ~65% of pure ligroin
• Dilutability: dilutable with water (ligroin is not)
• Selectivity: equivalent
• Surface residues: none
• Evaporation rate: comparable

Technical specifications

• Appearance: homogeneous white milky emulsion
• Water/ligroin ratio: equimolar
• pH (aqueous phase): 6.5–7.5
• Density (20 °C): 0.75–0.80 g/mL
• Flash point: >40 °C
• Viscosity (25 °C): 5–15 mPa·s
• Residues after evaporation: none
• Hansen Solubility Parameters (δD, δP, δH): 15.1, 1.2, 2.8 MPa½
• Preferential solubility: nonpolar substances (RED <1)

Safety & compliance Despite the improved risk profile, the following precautions are recommended: nitrile gloves, safety goggles, adequate ventilation. In confined spaces, use a Type A filter mask (organic vapours). Store in a cool, dry place away from heat sources (5–35 °C). Dispose according to local regulations for waste containing organic solvents. Full Safety Data Sheet available for download.

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