Solvent Selection for Industrial Degreasing

Contents

• How to use this guide
• Where it fits in a cleaning program
• Decision factors that matter (technical + commercial)
• Match solvent to cleaning method (wipe / immersion / spray / vapor)
• Solvent families & typical use-cases
• Key properties to specify (with practical thresholds)
• Materials compatibility (metals, plastics, elastomers)
• Residue control (NVR) & spotting risk
• EHS, flammability, VOC, transport & storage
• Bath management & contamination signals
• Simple verification tests (site-friendly)
• Troubleshooting (symptom → cause → fix)
• RFQ notes (procurement-ready)
• FAQ

How to use this guide

This is a practical decision aid for B2B teams. Use it to align procurement, EHS, and operations on selection criteria, acceptance checks, and monitoring signals. Start with the soil and the cleaning method, then eliminate incompatibilities and EHS blockers, and finish with residue and process verification tests.

Where it fits in a cleaning program

• Incoming parts / pre-clean: remove bulk oil to protect downstream washers and reduce soil loading.
• Precision cleaning step: reduce residues before painting, bonding, plating, or electronics assembly.
• Maintenance cleaning: wipe-downs for fixtures, workstations, and tooling.
• Rework / troubleshooting: targeted solvent use when aqueous systems cannot remove a specific contaminant.

Decision factors that matter (technical + commercial)

• Soil type: oils/grease, waxes, coolants, carbon, inks, adhesives, resins, silicone oils, particulates.
• Residue risk: “no residue” requirement, max NVR, spotting tolerance, and rinse availability.
• Drying behavior: evaporation rate vs entrapment risk (capillaries, blind holes, assemblies).
• Compatibility: plastics/elastomers/coatings/adhesives; seal swell and stress cracking are common hidden costs.
• EHS/compliance: flash point, LEL, VOC/HAP restrictions, worker exposure controls, ventilation and zoning.
• Commercial factors: supply continuity, consistent QC (batch-to-batch), packaging, lead time, and cost-in-use.

Match solvent to cleaning method

The “best solvent” changes with the method. Your process determines acceptable evaporation, exposure, and residue tolerance.

Wipe cleaning

• Priorities: fast dry, low odor (or controlled), low residue/NVR, safe handling in the work area.
• Common failure: streaking/film from high NVR or contaminated solvent; plastic attack on housings.
• Commercial note: standardize on one wipe solvent for most stations + a restricted-use stronger option for special soils.

Immersion / soak tanks

• Priorities: controlled evaporation, bath life, filterability for particulates, manageable waste stream.
• Common failure: bath contamination causing residue redeposition; swelling of seals/baskets/hoses.
• Commercial note: define “change-out” triggers and reclaim/disposal plan upfront.

Spray / recirculating systems

• Priorities: low foaming (if emulsifiers present), consistent viscosity, nozzle compatibility, quick separation of oils (if used with separators).
• Common failure: mist exposure and flammability concerns; inconsistent cleaning due to dilution drift.

Vapor degreasing (specialized)

• Priorities: stable boiling behavior, controlled emissions, strict EHS controls, consistent condensation cleaning.
• Common failure: solvent losses, regulatory constraints, or incompatible materials in the system.
• Note: This guide covers decision factors at a high level—always follow your equipment and EHS requirements for vapor processes.

Solvent families & typical use-cases

Hydrocarbons (aliphatic / isoparaffinic)

• Good for: oils, greases, many machining fluids (non-polar fraction).
• Why buyers like them: broad availability, stable, generally predictable on metals.
• Watch-outs: flammability, odor, slower evaporation in heavy grades, possible residue if high-boiling cut.

Oxygenated solvents (alcohols / ketones / esters / glycol ethers)

• Good for: inks, polar soils, many adhesives/resins, water displacing (in some cases).
• Why they work: polarity helps attack soils hydrocarbons struggle with.
• Watch-outs: plastics stress cracking and elastomer attack; often faster evaporation and higher flammability risk.

Terpenes / bio-based solvents

• Good for: resins/adhesives, sticky residues, some inks.
• Commercial benefit: sometimes preferred when buyers target “bio-based” profiles.
• Watch-outs: odor, residue/film, rinse requirement; confirm NVR and final cleanliness.

Solvent blends

• Good for: balancing solvency, evaporation, and residue with a tailored approach.
• Procurement requirement: request tight composition control and a clear COA to avoid batch drift.
• Watch-outs: changing blend ratios can change flash point, drying time, and compatibility—lock specs.

Key properties to specify (with practical thresholds)

These properties translate directly into process behavior and EHS handling. You don’t need every number—but you do need the ones that protect your process.

Materials compatibility

Compatibility issues are among the highest-cost failures: seals swell, plastics craze, coatings soften, and adhesives fail later. Screen early with representative samples.

High-risk materials to screen early

• Plastics: ABS, polycarbonate, acrylic (stress cracking risk with many oxygenated solvents).
• Elastomers: nitrile, EPDM, silicone, Viton/FKM (swell behavior varies widely).
• Coatings/paints: line markings, painted housings, powder coat, anodized finishes (spot test for whitening).
• Adhesives: bonded assemblies can fail even if the part “looks fine” immediately after cleaning.

Residue control (NVR) & spotting risk

“No-residue” is not just a marketing claim. Residue risk rises with high-boiling cuts, contaminated baths, or additives. If parts go to painting, bonding, plating, or electronics, specify NVR expectations and verify with evaporation tests.

Common residue sources

• High-boiling components or wide distillation range (slower evaporation leaves film)
• Bath contamination (oils, plasticizers, waxes, dissolved soils)
• Hard-water rinse (if used) causing spots/haze
• Overuse of corrosion inhibitors or non-volatile additives (process-specific)

EHS, flammability, VOC, transport & storage

• Flammability controls: define minimum flash point and required handling controls (grounding/bonding, ventilation, ignition control).
• Worker exposure: method matters—spray/mist increases exposure vs wipe; require SDS and site PPE/ventilation alignment.
• VOC/odor: confirm local/site limits; solvent choice may be constrained by odor complaints even when legal.
• Transport & labeling: ensure packaging and documentation match site receiving and hazardous goods requirements.
• Waste handling: define if spent solvent is reclaimed, distilled, or disposed; align with vendor support where possible.

Bath management & contamination signals

Solvent performance can degrade even if the solvent spec is good—bath contamination drives redeposition and residue. Build simple monitoring into operations.

• Visual clarity change: rising haze or color can signal dissolved soils.
• Residue increase: NVR test trending upward indicates contamination or wrong grade.
• Dry time drift: slower drying can indicate contamination or composition drift (especially in blends).
• Odor shift: can indicate contamination, oxidation, or wrong product delivered—verify batch traceability.

Simple verification tests (site-friendly)

NVR / residue test (quick)

• Evaporate a measured quantity on a clean stainless panel or glass dish.
• Inspect for visible film/spotting; if you have a balance, weigh before/after for a simple NVR estimate.
• Repeat with “fresh” solvent and “in-process” solvent to see contamination effect.

Cleaning performance trial

• Use real parts and real soils at actual dwell/temperature/agitation.
• Check for re-deposition, streaking, and dry time in worst-case geometry (holes/capillaries).
• If downstream is paint/bond/plating, include your standard adhesion/quality check.

Compatibility exposure test

• Expose representative plastics/elastomers/coatings for a controlled time.
• Inspect immediately and after 24–48 hours for delayed cracking or surface changes.

Troubleshooting (symptom → cause → fix)

RFQ notes (procurement-ready)

Strong RFQs include technical requirements and commercial constraints so suppliers can quote the correct grade, packaging, and compliance documents. Copy/paste the list below into your inquiry.

Technical fields (must-have)

• Method: wipe / immersion / spray / vapor; temperature; dwell; agitation/ultrasonics; drying method and cycle target.
• Soils: oil/grease type, coolant, wax, adhesive/ink/resin, particulate load; worst-case zone description.
• Materials: metals + plastics + elastomers + coatings + adhesives in contact (include baskets, hoses, seals).
• Residue requirement: “no visible residue” or max NVR; spotting tolerance; rinse availability.
• EHS constraints: minimum flash point, VOC/odor limits, storage/transport requirements, ventilation/zoning limitations.

Commercial fields (to price correctly)

• Volume: monthly usage and peak demand; expected bath change-out frequency if applicable.
• Packaging: pails/drums/IBC/bulk; preferred closures; pallet requirements if any.
• Delivery: destination country/city; Incoterms preference; receiving windows.
• Documents: SDS, COA per batch, traceability, and any compliance statements (e.g., REACH) if required by your site.

FAQ

Is “fast drying” always better?

Not always. Fast evaporation can increase exposure risk and can trap solvent in blind holes if airflow is poor. Define dry-time targets based on geometry and downstream requirements, then validate with real parts.

What if we need “no residue” but also high solvency?

Prioritize low NVR and a tighter distillation profile, then validate on your soils. In many cases, a controlled blend can balance solvency and residue, but batch consistency must be locked via COA requirements.

Why does the same solvent behave differently between batches?

Wide cut ranges, blend ratio drift, or contamination can change evaporation, odor, and residue. Specify distillation range and critical COA items, and keep lot traceability on receiving.

Educational content only. Always follow site EHS rules and the supplier SDS for safe use.