Carboxane 2000 - Polysiloxane Topcoat for Superior Weathering

Q: What is the coverage rate for Carboxane 2000?

Carboxane 2000 covers 401 ft2/gal at 3.0 mils DFT and 172 ft2/gal at 7.0 mils DFT (theoretical, based on 75% volume solids). The recommended DFT is 3-7 mils per coat. As the finish of a two-coat system over a primer, a minimum of 5 mils is recommended. As the finish of a three-coat system with a primer and intermediate coat, a minimum of 3 mils is recommended. Allow for loss in mixing and application.

Q: Is Carboxane 2000 isocyanate-free?

Yes. Carboxane 2000 is completely isocyanate-free. Unlike aliphatic polyurethanes (which use isocyanate crosslinkers), Carboxane 2000 uses a hybrid siloxane binder chemistry that delivers superior UV resistance and weathering durability without the isocyanate exposure hazards associated with polyurethane coatings.

Q: How does Carboxane 2000 compare to polyurethane topcoats?

Carboxane 2000 exceeds SSPC Paint 36 Level 3A -- a higher weathering classification than most aliphatic polyurethanes. The product flyer shows Carboxane 2000 achieving over 10,000 hours to 25% gloss loss in QUV-A testing, far exceeding even Level 3 urethanes. It is isocyanate-free, simplifying applicator safety requirements. When used over a primer as a two-coat system, it replaces the three-coat (primer, epoxy intermediate, polyurethane topcoat) system typically required for most environments.

Q: What is the mix ratio and pot life for Carboxane 2000?

Carboxane 2000 uses a 2.2:1 mix ratio by volume (Part A to Part B). Power mix Part A separately; Part B requires no mixing. Then combine and power mix. Do not mix partial kits. Pot life is 8 hours at 75F (23C) -- one of the longest in its product category. Material is moisture sensitive; if left uncovered for extended periods or under very high humidity, check for and remove any skinning before use.

Q: What is the maximum recoat time for Carboxane 2000?

Carboxane 2000 has a maximum recoat window of 30 days. After 30 days, degloss the surface by abrasive blasting or sanding before recoating. This differs from the indefinite recoat window of Carbothane polyurethane products. Note: like many coatings, Carboxane 2000 develops full adhesion over the initial weeks following application.

Q: What specifications does Carboxane 2000 meet?

Carboxane 2000 exceeds SSPC Coating Specification No. 36 Level 3A and meets ISO 12944 C3 High and C4 Medium when applied in one coat at 5-7 mils DFT. It also carries a Flame Spread Index of 0 and Smoke Developed Index of 10 for surface burning characteristics.

Q: Can Carboxane 2000 be applied directly to bare steel?

Carboxane 2000 is self-priming and can be applied direct-to-metal (DTM) in mild environments. For moderate to heavily corrosive environments, prime with Carbozinc, Carboguard, or Carbomastic Series products or other Carboline-recommended primers. When used over a zinc-rich primer as a two-coat system, it provides the corrosion and weathering performance normally achieved with a three-coat system.

Thinner	Use	Max Rate
Thinner 10	Spray application	10% (13 oz/gal)
Thinner 214	Brush & roller application	Per PDS
Thinner 215	Brush & roller application	Per PDS
Thinner 238	Brush & roller application	Per PDS
Thinner 2 or Acetone	Cleanup only	—

Thinner

Use

Max Rate

Thinner 10

Spray application

10% (13 oz/gal)

Thinner 214

Brush & roller application

Per PDS

Thinner 215

Brush & roller application

Per PDS

Thinner 238

Brush & roller application

Per PDS

Thinner 2 or Acetone

Cleanup only

—

Product Specs — Carboxane 2000

Carboxane 2000 — Isocyanate-Free Modified Siloxane Hybrid Topcoat by Carboline.
An ultra-durable, high-gloss finish coat that delivers weathering performance far exceeding aliphatic polyurethanes — while being completely isocyanate-free. The UV-resistant siloxane binder provides extreme color and gloss retention, chalk resistance, and corrosion protection for exterior exposures. When used over a primer as a two-coat system, it replaces the three-coat epoxy system typically required for most environments, saving labor and cost without sacrificing performance. Self-priming in mild environments.

✓ Isocyanate-Free • ✓ Exceeds SSPC Paint 36 Level 3A • ✓ ISO 12944 C3 High & C4 Medium • ✓ Flame Spread Index: 0 • ✓ Self-Priming (Mild Environments) • ✓ VOC Compliant

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Carboxane 2000 by Carboline

Carboxane 2000 isocyanate-free hybrid siloxane topcoat by Carboline — 1-gallon and 5-gallon kits — Carboxane 2000 — 1-Gal & 5-Gal Kits (Parts A & B)

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US regional warehouse map showing estimated shipping transit times for Carboline product orders from Material Warehouse — Typical transit times vary by destination zone. Click map to enlarge.

Shipping Time

Call (800) 567-5358 for pricing and logistics questions.

Carboline orders ship from regional warehouses nearest to your location, with full product stock maintained at each facility.

Shipping day 1 is the next business day after the order has been received.

Coverage Rates & Technical Specifications

Recommended DFT: 3–7 mils per coat. 75% volume solids. As the finish of a two-coat system over a primer, a minimum of 5 mils is recommended. As the finish of a three-coat system, a minimum of 3 mils is recommended. Allow for loss in mixing and application.

Property	Value	Notes
Generic Type	Modified Siloxane Hybrid	Not a polyurethane — isocyanate-free binder chemistry
Finish	Gloss	Outstanding long-term color and gloss retention
Volume Solids	75% ±2%	—
Recommended DFT	3–7 mils (76–178 µm) per coat	Min 5 mils over primer (2-coat); min 3 mils in 3-coat system
Coverage @ 1 mil	1,203 ft²/gal (29.5 m²/l)	Theoretical — allow for loss
Coverage @ 3 mils	401 ft²/gal (9.8 m²/l)	Theoretical — minimum 3-coat system DFT
Coverage @ 5 mils	241 ft²/gal (5.9 m²/l)	Theoretical — minimum 2-coat system DFT
Coverage @ 7 mils	172 ft²/gal (4.2 m²/l)	Theoretical — maximum recommended DFT
Mix Ratio	2.2:1 by volume (Part A to Part B)	Do not mix partial kits
Pot Life	8 hours at 75°F (23°C)	Less at higher temps · moisture sensitive (check for skinning)
VOC (As Supplied, Mixed)	1.8 lbs/gal (216 g/l)	With Thinner 10 at 13 oz/gal: 2.29 lbs/gal (275 g/l)
Isocyanate-Free	Yes	No isocyanate hazards during application
Min Application Temp	Material 50°F (10°C) · Surface 35°F (2°C)	—
Max Application Temp	Material 90°F (32°C) · Surface 110°F (43°C)	—
Humidity Range	20–90% RH	Minimum 20% RH required — unusual floor vs. most topcoats
Dry to Touch @ 75°F	2 hours	—
Dry to Recoat @ 75°F	6 hours	Maximum recoat window: 30 days (then degloss required)
Hard Cure @ 75°F	18 hours	Hard Cure = Fingernail hard
Dry Temp. Resistance	302°F (150°C) continuous · 338°F (170°C) non-continuous	Some discoloration/gloss loss at elevated temps
Surface Burning	Flame Spread Index: 0 · Smoke Developed Index: 10	—
SSPC Compliance	Exceeds SSPC Paint 36 Level 3A	Higher than Level 3 — outperforms aliphatic polyurethanes
ISO 12944	C3 High and C4 Medium	One coat at 5–7 mils DFT
Self-Priming	Yes (mild environments)	Prime with Carbozinc/Carboguard/Carbomastic for moderate-severe service
Thinning (Spray)	Thinner 10 (up to 10%, 13 oz/gal)	Not normally required
Thinning (Brush/Roller)	Thinner 214, 215, or 238	Not normally required
Cleanup	Thinner 2 or Acetone	—
Shelf Life — Part A	24 months at 76°F (24°C)	Unopened, stored indoors and dry
Shelf Life — Part B	24 months at 76°F (24°C)	Unopened, stored indoors and dry
Storage	Indoors · Keep Dry · 40–110°F · 0–90% RH	Not affected by excursions to 10°F for up to 14 days
Flash Point — Part A	96°F (36°C)	Setaflash
Flash Point — Part B	75°F (24°C)	Setaflash
Kit Sizes	1-gal (13 lbs) · 5-gal (67 lbs)	—

Source: Carboline Carboxane 2000 Product Data Sheet (February 2023, doc 2000). Coverage rates are theoretical — actual yield varies with surface profile, temperature, and application method.

Application Conditions

Condition	Material	Surface	Ambient	Humidity
Minimum	50°F (10°C)	35°F (2°C)	35°F (2°C)	20%
Maximum	90°F (32°C)	110°F (43°C)	110°F (43°C)	90%

⚠️ Substrate temperature must be at least 5°F (3°C) above the dew point. Protect from high humidity, dew, and direct moisture contact until fully cured. Application above 90% RH or exposure to moisture from rain or dew may result in gloss loss or staining. Note the 20% minimum humidity — application in very dry conditions will be insufficient for proper cure.

Curing Schedule

Surface Temp.	Dry to Touch	Dry to Recoat	Hard Cure
35°F (2°C)	8 Hours	24 Hours	30 Hours
60°F (16°C)	3 Hours	12 Hours	24 Hours
75°F (24°C)	2 Hours	6 Hours	18 Hours

Based on recommended coverage rates. Curing under low humidity conditions will extend times. Hard Cure = Fingernail hard.

Maximum recoat window: 30 days. After 30 days, degloss the surface by abrasive blasting or sanding before recoating. This is different from the Carbothane 133/134 series, which has an indefinite recoat window.

Note: Like many coatings, Carboxane 2000 will develop full adhesion over the initial weeks following application.

Good to Know Before You Buy

⚠️ Application Notes & Pro Tips

Isocyanate-free — genuinely different chemistry. Unlike aliphatic polyurethanes (Carbothane 133/134 series), Carboxane 2000 contains no isocyanates. This eliminates the respiratory sensitization hazard associated with isocyanate-based coatings and simplifies applicator PPE requirements in many jurisdictions.
2.2:1 mix ratio — an unusual number; measure carefully. Most two-component coatings use round-number ratios. The 2.2:1 ratio requires precise measurement. Do not mix partial kits. Power mix Part A first; Part B requires no pre-mixing before combining.
8-hour pot life at 75°F — one of the longest available. Significantly more working time than Carbothane polyurethane products (4–6 hours). However, the material is moisture sensitive — if left uncovered for extended periods or in very high humidity, check for and remove any skinning before use.
Maximum recoat is 30 days — set a reminder. Unlike the indefinite recoat window of Carbothane 133/134 products, Carboxane 2000 must be recoated within 30 days or the surface must be deglossed by abrasive blasting or sanding before the next coat. Plan sequencing accordingly on large projects.
Minimum 20% relative humidity required. This minimum humidity floor is unusual — most topcoats have no lower humidity limit. Very dry conditions (below 20% RH) will inhibit proper cure. Do not apply in extremely dry, arid conditions without monitoring.
Outperforms even Level 3 polyurethanes in QUV-A weathering. The product flyer shows Carboxane 2000 achieving over 10,000 hours to 25% gloss loss in QUV-A exposure — compared to roughly 2,000–3,000 hours for Level 3 aliphatic polyurethanes. This translates directly to fewer repaints over the service life of a structure.
Thinning is not normally required. Carboxane 2000 is formulated for direct application at most temperatures. Only thin when job site conditions demand it: Thinner 10 for spray (up to 10%); Thinner 214, 215, or 238 for brush and roller. Cleanup uses Thinner 2 or acetone.
Full adhesion develops over initial weeks. The PDS notes explicitly that, like many coatings, Carboxane 2000 develops full adhesion over the weeks following application. Do not test adhesion or put the structure into heavy service immediately after the hard cure milestone.
Flash point of Part B is 75°F (24°C) — flammable at ambient temperature. Part B has a lower flash point than most coating components. Apply all standard precautions for flammable solvents; keep away from sparks and open flames and ensure adequate ventilation.

Frequently Asked Questions — Carboxane 2000

What is the coverage rate for Carboxane 2000?

Carboxane 2000 covers 401 ft²/gal at 3.0 mils DFT and 172 ft²/gal at 7.0 mils DFT (theoretical, based on 75% volume solids). As the finish of a two-coat system over a primer, a minimum of 5 mils is recommended. As the finish of a three-coat system, a minimum of 3 mils is recommended. Allow for loss in mixing and application.

Is Carboxane 2000 isocyanate-free?

Yes — Carboxane 2000 is completely isocyanate-free. Unlike aliphatic polyurethanes such as the Carbothane 133/134 series, which use isocyanate crosslinkers (Urethane Converter 811), Carboxane 2000 uses a hybrid siloxane binder that delivers superior UV resistance and weathering durability without the isocyanate exposure hazards associated with two-component polyurethane coatings.

How does Carboxane 2000 compare to polyurethane topcoats?

Carboxane 2000 exceeds SSPC Paint 36 Level 3A — a higher weathering classification than Level 3 aliphatic polyurethanes such as Carbothane 134 HG. In QUV-A testing, Carboxane 2000 achieves over 10,000 hours to 25% gloss loss, compared to roughly 2,000–3,000 hours for Level 3 urethanes. It is isocyanate-free, simplifying applicator safety. When used over a primer as a two-coat system, it replaces the three-coat system (primer, epoxy intermediate, polyurethane topcoat) typically required for most environments.

What is the mix ratio and pot life for Carboxane 2000?

Carboxane 2000 uses a 2.2:1 mix ratio by volume (Part A to Part B). Power mix Part A separately — Part B requires no pre-mixing. Then combine and power mix. Do not mix partial kits. Pot life is 8 hours at 75°F (23°C) — one of the longest for any two-component topcoat. The material is moisture sensitive; if left uncovered for extended periods or in high humidity, check for and remove any skinning before use.

What is the maximum recoat time for Carboxane 2000?

Carboxane 2000 has a maximum recoat window of 30 days. After 30 days, degloss the surface by abrasive blasting or sanding prior to recoating. This is an important difference from the Carbothane 133/134 series, which has an indefinite recoat window. Note that full adhesion develops over the initial weeks following application.

What specifications does Carboxane 2000 meet?

Carboxane 2000 exceeds SSPC Coating Specification No. 36 Level 3A and meets ISO 12944 C3 High and C4 Medium when applied in one coat at 5–7 mils DFT. It carries a Flame Spread Index of 0 and a Smoke Developed Index of 10. It is also VOC compliant to applicable regulations at 1.8 lbs/gal (216 g/l) as supplied mixed.

Can Carboxane 2000 be applied directly to bare steel?

Carboxane 2000 is self-priming and can be applied direct-to-metal (DTM) in mild environments. For moderate to heavily corrosive environments, prime with Carbozinc, Carboguard, or Carbomastic Series products or other Carboline-recommended primers. When used over a zinc-rich primer as a two-coat system at a minimum of 5 mils DFT, it provides the corrosion and weathering performance normally associated with a three-coat system for most environments.

What humidity is required to apply Carboxane 2000?

Carboxane 2000 requires a minimum of 20% relative humidity and a maximum of 90% RH for application. The 20% floor is worth noting — most coatings have no lower humidity limit, but Carboxane 2000 requires sufficient atmospheric moisture for proper cure. Very dry conditions below 20% RH will inhibit curing and should be avoided. Low humidity conditions (even above 20%) will also extend curing times.