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Hempaline Defend 740

Hempaline Defend 740

Product characteristics

Description
Hempaline Defend 740 is a sprayable high performance novolac glass flake vinyl ester tank lining. Hempaline Defend 740 has excellent resistance to organic and inorganic acid solutions, high temperatures and abrasion conditions.

Recommended use
Hempaline Defend 740 is recommended as internal lining on steel or concrete for chemical storage tanks and vessels where acidic environments at elevated temperatures and pressures might be experienced in the oil & gas industry.

Service temperature:

  • Maximum, dry exposure only: 192°C [378°F].
  • Please contact Hempel for more information.
  • Please consult the Chemical protection guide at hempel.com.
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Product safety

Flash point: 28°C [82°F]

VOC content mixed product

Legislation Value
EU 40 g/L [0.33 lb/US gal]
US (coatings) 40 g/L [0.33 lb/US gal]
US (regulatory) 40 g/L [0.33 lb/US gal]
China 40 g/L [0.33 lb/US gal]

According to specific legislation. See Explanatory Notes at hempel.com or your local Hempel website.

Handling
Handle with care. Observe safety labels and follow local/national regulations.
Always consult Hempel’s Safety Data Sheet along with the Product Data Sheet.
For professional use only.


Product data

  • Product code: 17120
  • Base: 17129
  • Curing Agent: 9580A
  • Standard shade: Light beige 15974
  • Gloss: Semi-gloss
  • Volume solids: 100%
  • Specific gravity: 1.3 kg/L [11 lb/US gal]
  • Reference dry film thickness: 500 micron [20 mils]

Surface preparation

Cleanliness

  • Remove oil, grease using detergent.
  • Remove salts and contaminants via high-pressure fresh water.
  • For concrete: see Hempel’s Specification.

New build

  • Abrasive blasting to min. Sa 2½ (ISO 8501-1) / SP 10 (SSPC).
  • Remove dust and loose materials.

Roughness

  • Surface profile Medium (G) (ISO 8503-2)

Refer to Hempel’s Surface Preparation Guidelines.


Application

Mixing ratio: Base 17129 : Curing Agent 9580A (49 : 1 by volume)
Stir well before use. Thinning not allowed.

Thinner: None
Cleaner: Hempel’s Thinner 08960

Pot life

Temp Pot life
10°C [50°F] 60 min
20°C [68°F] 40 min
30°C [86°F] 25 min

Application method

Tool Thinning Parameters
Airless spray None Pressure: 200 bar [2900 psi], Nozzle: 0.025–0.048″

As tank lining, brush/roller use is for stripe coating or touch-up only. Heavy-duty spray equipment needed. Keep hoses short. Pressure based on 20°C material.


Film thickness

Category DFT WFT Spreading rate
Low 400 µm [16 mils] 401 µm [16 mils] 2.5 m²/L [102 sq ft/US gal]
High 1000 µm [40 mils] 1001 µm [40 mils] 1 m²/L [41 sq ft/US gal]
Recommended 500 µm [20 mils] 501 µm [20 mils] 2 m²/L [81 sq ft/US gal]

Thickness may vary depending on use case. This affects drying, curing, and coverage.


Application conditions

  • Optimal paint temperature: 20–25°C [68–77°F]
  • Surface must be 3°C above dew point and >10°C [50°F]
  • Ensure surface is clean and dry

Application remarks

  • Although solids = 100%, some reactive volatiles may evaporate.
  • Curing contraction also affects volume.
  • Use 85% practical volume solids for estimating coverage.

Drying and overcoating

Product compatibility

  • Previous coat: None or as per specification. Suggested: Hempaline Prepare 120
  • Next coat: None or as per specification. Suggested: Hempaline Defend 740

Drying time

Surface temperature 10°C [50°F] 20°C [68°F] 30°C [86°F] 35°C [95°F]
Surface dry (h) 7 4 2.5 2
Hard dry (h) 7
Through dry (h) 13 8 5 4
Walkable (h) 24 15 10 8
Fully cured (h) 72 34 21 16

Based on 500 µm [20 mils] DFT under standard conditions. See Explanatory Notes.


Overcoating

Recommended intervals for immersion

Quality name 10°C [50°F] 20°C [68°F] 30°C [86°F]
Hempaline Defend 740 – / – – / – – / –

No defined overcoating window listed; follow Hempel’s specification.

Overcoating details

  • If max interval is exceeded, sweep blast required
  • Surface must be clean and dry before coating

Other remarks

  • Hempel’s Specification supersedes any PDS suggestions.

Storage

Temp Base shelf life Curing Agent shelf life
25°C 6 months 6 months

Store in original, unopened containers below 40°C. Reinspect after shelf life.


Carbon Footprint

Thickness GWP (CO₂e)
1 µm 7.2 g CO₂e/m²
1 mil 0.037 lb CO₂e/ft²

Includes raw materials, production, VOCs. Based on standard shade. Values may vary.


References

Product Data Sheet – Hempaline Defend 740
Issued by Hempel A/S – May 2025
Document Version: 4/4
Source: https://www.hempel.com

Technical Guidelines and Explanatory Notes
Last accessed: 28 May 2025
Reference link: https://www.hempel.com/service-and-support/technical-guidelines

Note: Always consult the latest version of the Product Data Sheet and associated documents directly from Hempel’s official website to ensure accuracy and compliance with the most current recommendations.