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Anti-Sagging Resin 908R
Hydroxy-functional SCA paste for two-component polyurethane automotive and industrial topcoats.
Positioned against Nuplex 81198
Product Overview
908R is a high weather resistance modified hydroxy acrylic resin containing an extremely fine polyurea crystal structure. Because the resin itself carries hydroxy functionality at 100 mg KOH/g on solids, it takes part in the two-component polyurethane crosslink instead of sitting in the film as inert thixotrope. It is used in hydroxy two-component urethane automotive and industrial coatings.
Key Benefits
- Hydroxy value of 100 mg KOH/g on solids, so it crosslinks into the 2K polyurethane network
- High weather resistance, which matters for exterior automotive topcoats
- Fine polyurea crystal structure below 15 microns keeps the finish smooth
- Thixotropy of 4-9 gives sag control at high film build
- Supplied as a paste at 50-53% solids in xylene / n-butyl acetate
At A Glance
- Chemistry
- Modified hydroxy acrylic resin with polyurea crystal structure
- Family
- Sag Control Agents
- Category
- Sag Control Resins
- Positioned against
- Nuplex 81198
- Appearance reference
- Pale yellow translucent paste
Who It Is For
- Automotive refinish formulators working in 2K polyurethane
- Industrial coating producers needing high film build in one pass
Problems It Solves
- Runs and sags when film build is pushed to meet a corrosion specification
- Inert thixotropes that weaken the cured film
- Weathering failure on exterior topcoats
Application Scenarios
- Two-component polyurethane automotive topcoats
- Two-component industrial coatings on vertical steelwork
- High-build single-pass applications where sagging is the limit
Technical Features
- Modified hydroxy acrylic resin containing fine polyurea crystals
- Amine value below 8 mg KOH/g on solids
- Fineness below 15 microns
- Specific gravity 0.97-1.02 at 25C
Typical Data And Dosage
Typical values are indicative of the product and are not release specifications. Figures are reproduced from the manufacturer data sheet.
| Appearance | Pale yellow translucent paste |
| Solids (120C x 60 min) | 50-53 wt% |
| Thixotropy (23C, 6 rpm / 60 rpm) | 4-9 |
| OH value | 100 mg KOH/g on solids |
| Amine value | Below 8 mg KOH/g |
| Fineness | Below 15 microns |
| Specific gravity (25C) | 0.97-1.02 |
| Solvent | Xylene / n-butyl acetate 80/20 |
| Storage | Below 30C |
| Shelf life | 12 months |
| Packing | 200 kg drum |
Recommended Dosage
All dispersant and additive dosage figures below are quoted exactly as the source data sheet quotes them. Dispersant figures are percentages on pigment weight, not on the total batch. The published values are empirical, so confirm the optimum with a dosage ladder in your own system.
| On finished formulation | 7-11% |
Use Guide
- Dose at 7-11% on the finished formula.
- Account for the hydroxy contribution when calculating the isocyanate ratio, since 908R carries an OH value of 100 mg KOH/g on solids.
- Store below 30C. Shelf life is 12 months.
Quality Control On Your Side
- Measure sag resistance on a sag bar at the target film build
- Confirm the NCO/OH ratio after the SCA contribution is included
- Check gloss and appearance on cured panels
How It Compares With The Alternatives
Technical comparison against other ways of solving the same problem. Nothing here is a performance claim against a named commercial product.
| 904R | 904R is a urea-modified grade for metallic orientation; 908R is hydroxy-functional and crosslinks into 2K polyurethane. |
| 906S | 906S is a fluid SCA at 58-62% solids with finer 10 micron structure; 908R is a paste with hydroxy functionality. |
| Fumed silica | No dust handling and no high-shear pre-dispersion, and it does not dull gloss the way silica loading can. |
Customisation And Supply
- Packing as published on this page; other pack sizes are confirmed per order
- Technical data sheet and, where available, safety data sheet supplied by email on request
- Tailor-made products can be discussed; send the property you need and the system it goes into
- Shipped from Tianjin, China by sea or air
Anti-Sagging Resin 908R Questions
Does 908R affect the isocyanate ratio?
What dosage is recommended?
How should it be stored?
What packing is available?
Products Often Considered Alongside This One
Anti-Sagging Resin 906S
Fluid SCA at 58-62% solids for high quality automotive solid colours and clearcoats.
View technical data
Anti-Sagging Resin 904R
Urethane SCA for metallic automotive and industrial coatings, with unusually good CAB compatibility.
View technical data
QK4100 Liquid Rheological Agent
Liquid polyurea thixotrope for solventborne and solvent-free coatings, PVC plastisol and air-drying resin systems.
View technical dataGuides That Cover This Product
Where It Is Used
Request Anti-Sagging Resin 908R
Send your system type, pigment loading and required quantity. A quotation and the full data sheet come back by email.