In catheter manufacturing, hydrophilic coatings are expected to deliver smooth trackability, lower insertion force, and dependable clinical performance. Yet many manufacturers still battle coating rejects, unstable yields, and unexplained lot-to-lot variation.
While coating chemistry often gets blamed, the true problem is frequently found upstream—on the catheter surface before coating begins.
Residual oils, mold release compounds, adhesive traces, fibers, and particles can prevent proper coating adhesion and create costly defects.
That is why leading manufacturers are re-evaluating one overlooked process variable:
The wipe used to prepare catheter surfaces before coating.
Why Surface Cleanliness Matters Before Hydrophilic Coating
Hydrophilic coatings depend on intimate contact with the catheter substrate. If contamination remains on the shaft, the coating may not wet evenly or bond consistently.
Common contamination sources include:
- Extrusion oils
- Slip additives
- Mold release residues
- Operator handling oils
- Adhesive smears
- Polyester wipe fibers
- Airborne particles
- Packaging dust
Even invisible contamination can cause major downstream yield loss.
Common Coating Defects Caused by Residues and Particles
When catheter surfaces are not fully cleaned, manufacturers may experience:
Adhesion Failures
- Peeling
- Flaking
- Delamination
- Early wear
Appearance Defects
- Fish-eyes
- Craters
- Haze
- Streaks
- Uneven gloss
Functional Defects
- Inconsistent lubricity
- Higher friction
- Rough feel
Hidden Costs
- Scrap
- Rework
- Inspection rejects
- Lot instability
Why Different Catheter Materials Need Better Cleaning
Different substrates carry different residue risks.
Pebax Shafts
Often retain extrusion oils and slip additives that reduce coating wetting.
Nylon Components
May carry mold release or processing lubricants that weaken adhesion.
Polyurethane Parts
Soft surfaces can attract particles and handling residues.
PTFE Liners
Low surface energy makes cleanliness and pretreatment critical.
Multilayer Catheters
Mixed materials increase variability and make standardized cleaning more important.
Why UltraSORB® Performs Differently
Unlike textile wipes, UltraSORB is hydrophilic polyurethane foam.
HT4699 UltraSORB Wiper Wipe .109″x9″x9″
Zero Fibers by Construction
No yarns or textile fibers to shed onto catheter surfaces.
Superior Oil & Residue Removal
Absorbs and retains oily contamination instead of smearing it.
Hydrophilic Wetting Advantage
UltraSORB wets quickly with IPA or approved cleaning fluids and spreads liquid evenly across the wipe surface.
This helps operators apply fluid consistently along the entire catheter length, reducing dry spots and over-wet zones.
Structured Pore Network
Captures particles within the foam matrix.
Soft, Non-Abrasive Surface
Ideal for delicate shafts and coated assemblies.
Real-World Performance
A leading catheter manufacturer using UltraSORB® in their hydrophilic coating area reported measurable improvements after replacing legacy polyester wipes.
Their primary objective was to remove oily residues that interfere with coating adhesion, but the results extended well beyond surface cleanliness.
They reported:
- More stable coating yields
- Foreign material (FM) rejects reduced by more than 50%
- Rework reduced by more than 50%
- Easier operator handling
- Softer feel than polyester wipes
- Better grip and wipe control during repetitive cleaning steps
They also noted that embedded fibers had previously been observed—an issue commonly associated with textile wiping materials.
By switching to hydrophilic polyurethane foam wipes with zero fibers by construction, they improved both coating consistency and overall manufacturing quality performance.
Learn more about UltraSORB wipes