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Merbenit HM21

Merbenit HM21

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Universal 1K SMP sealant with long working time, Shore A 45 and 350% elongation at break.

Universal 1K SMP sealant with long working time (30 min), Shore A 45 and 350% elongation at break — EMICODE EC1Plus + Eurofins IAC Gold certified

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  • Tensile strength
  • Temperature range (°C)
  • Container
  • consistency
  • Elongation at break
  • density
  • Hardness (Shore A)
  • Chemical group
  • Color
  • Cured layer thickness after 24 hours
  • curing technique
  • Processing temperature
  • Tension at 100% elongation
  • Change in volume
  • Number of components

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MS Polymer Universal Automatic Dispensing General Industry and Manufacturing Construction Metal Plastic Low Odor Solvent-Free Silicone- Free Isocyanate-Free Automotive Elastic Merbenit Accessories Spray Guns Sealant Mechanical Engineering

 
General Terms and Conditions.

Shipping usually within 1 to 3 business days
(availability will be confirmed after ordering)

. Express logistics. Fast and reliable within Switzerland & Europe.

Shipping from Swiss warehouse within 24 hours. Batch certificate. Invoice within 30 days (B2B). Technical support.
Shipping & Delivery

Usually 1 to 3 working days

Availability will be confirmed after order receipt.

Express logistics within Switzerland & Europe.

General Terms and Conditions →

Product data

HS code: 3214.1000

HS code: 3214.1000

Merbenit HM21
Merbenit HM21
Merbenite ·

Merbenit HM21 is a universal 1K-SMP sealant with a long working time (30 min), Shore A 45 and 350% elongation at break — EMICODE EC1Plus + Eurofins IAC Gold certified.

Silane-modified polymers (SMPs) are modern, high-performance adhesives—moisture-curing, solvent-, isocyanate-, and silicone-free, with a very broad adhesion spectrum to metals, painted and galvanized surfaces, engineering plastics, glass, ceramics, concrete, stone, and wood. They are paintable, corrosion-resistant, shock- and vibration-resistant, and low-odor. HM21 is a specific variant of the Merbenit SMP series—its key properties and applications are described below.

Long pot life + EMICODE EC1Plus

Merbenit HM21 is the universal choice in the Merbenit range — its 30-minute working time allows for careful application of even large adhesive joints, with high final strength (Shore A 45) and 350% elongation at break. EMICODE EC1Plus and Eurofins IAC Gold certifications confirm very low-emission processing — suitable for interior applications.

HM21 in figures
Shore A 45
hardness
30 min
Potting time
350 %
Elongation at break
EMICODE EC1Plus
low emissions

What makes HM21 stand out

Long processing time (30 min)
Careful processing of even large glued seams without haste.
EMICODE EC1Plus + Eurofins IAC Gold
Very low emissions — certified for indoor applications.
Very broad adhesion spectrum
Metals, painted and galvanized surfaces, plastics, glass, ceramics, concrete, stone, wood.
High elongation at break (350%)
Withstands strong movements — tolerance-compensating.
Paintable, sandable and varnishable
Can be painted over with varnishes after hardening.
Solvent-, isocyanate-, silicone- and phthalate-free
Safe in processing and in the workplace.

What is HM21 used for?

Metal construction
Flexible adhesive and sealing connections in metal construction.
Apparatus and machine construction
Universal adhesive with long pot life.
Plastics Technology
Bonding of engineering plastics to metals.
Ventilation and air conditioning technology
Sealing and bonding in HVAC systems.
Bodywork, wagon, vehicle and container construction
Tolerance compensation connections with weather resistance.
Interior applications
EMICODE EC1Plus allows use in living and working spaces.
Data sheets & safety data sheet
TDS and SDS in multiple languages ​​— watch or download directly.
To the documents →

processing

1
clean substrate
Bonding surfaces should be clean, grease-free, and dry — degrease with rubbing alcohol, isopropanol, or acetone. Bonding to PP, PE, PTFE, and silicone is not possible; bitumen substrates are also unsuitable.
2
Primer (if needed)
Use Primer V40 on smooth substrates, and Primer V21 on absorbent substrates. Primer V40 is recommended for powder-coated surfaces and plastics.
3
Open cartridge/bag
Cut the cartridge tip to the desired cross-section of the bead and insert it into a standard cartridge gun (290 / 310 / 400 / 600 ml).
4
Apply
Apply a uniform bead or dot of adhesive. Join within the pot life – press the components together with sufficient pressure.
5
Smoothing + Correcting
Smooth or correct position with a smoothing tool within the processing time (5–30 min depending on the variant).
6
Curing
Cross-linking through humidity — curing 2–3 mm in 24 h, fully cross-linked after 48 h. Higher humidity accelerates cross-linking.

Recommended accessories

Merbenit HT50
Instant adhesion 1K-SMP — bonded parts are immediately transportable, ISEGA approved.
View product →
Merbenit HS60
High-modulus 1K-SMP (Shore A 60) with ISEGA + RLT VDI 6022 — highest strength in the series.
View product →
Merbenit TMS32
500% elongation at break — highest tolerance for natural stone, wooden floors, sanitary joints.
View product →
Merbenit SF50
Fast-setting 1K-SMP adhesive for Minergie-ECO construction projects with eco-bau ECO-BKP 1st priority.
View product →

HM21 compared to related Merbenit products

Direct comparison of mechanical and processing values ​​— all data from the official Merbenit TDS.

HM21
Current product		 HT50 →SF50 →HS60 →
Networking system1K moisture-curing1K moisture-curing1K moisture-curing1K moisture-curing
consistencystable, ≤3 mmstablestablestable
Shore A hardnessA 45A 45A 50A 60
Tensile strength2.5 N/mm²2.5 N/mm²3.4 N/mm²3.3 N/mm²
Elongation at break350 %200 %200 %250 %
Module 100%1.6 N/mm²1.5 N/mm²2.2 N/mm²2.3 N/mm²
Processing time30 min10 min8 min10 min
Curing time: 24 hours≥3.0 mm2.5 mm≥3.5 mm≥2.0 mm
Curing time: 48 hours≥4.0 mm4.0 mm≥4.5 mm≥3.0 mm
density1.521.481.401.54
Temperature range-40 / +90 °C-40 / +90 °C-40 / +90 °C-40 / +90 °C
Change in volume≤5 %≤4 %≤7 %≤8 %
Main applicationMetal constructionInstant adhesivesMinergie-ECO building projectsFood industry
Topics & Application Areas
Key terms related to this product. Also useful for our search and filters.
MS Polymer Universal Automatic Dispensing General Industry and Manufacturing Construction Metal Plastic Low Odor Solvent-Free Silicone- Free Isocyanate-Free Automotive Elastic Merbenit Accessories Spray Guns Sealant Mechanical Engineering

Technical data for Merbenit HM21

All 15 product information 4 Performance at final strength 1 Physical properties 6 General 4
Product information
Tensile strength approx. 2.5 N/mm²
Temperature range (°C) -40 °C to +90 °C
Container 290ml cartridge, 600ml bag
consistency Stable, ≤ 3 mm
Performance at final strength
Elongation at break approximately 350%
Physical properties
density 1.52 g/cm³
Hardness (Shore A) 45
Chemical group Silane-modified polymer
Color black, white, grey
Cured layer thickness after 24 hours ≥ 3.0 mm
curing technique Moisture-curing
Generally
Processing temperature +5 °C to +40 °C
Tension at 100% elongation approx. 1.6 N/mm²
Change in volume ≤ 5%
Number of components 1K

For binding values, please refer to the technical data sheet (TDS) in the "Documents" tab.

Documents and datasheets

Click on a document for a preview or the download icon for a direct download.

Safety Data Sheets (SDS) 2
Merbenit HM21 - Safety Data Sheet DE.pdf
76 KB
Merbenit HM21 - Fiche de Sécurité FR.pdf
76 KB

Frequently asked questions about HM21

Practical application and design questions — answered by SILITECH.

Merbenit HM21: Universal 1K SMP sealant with a long working time (30 min), Shore A 45 and 350% elongation at break — EMICODE EC1Plus + Eurofins IAC Gold certified. Main applications: Metal construction, apparatus and machine construction, plastics technology.

SMP = Silane-modified polymer. This modern class of adhesives combines the advantages of silicone (elasticity, weather resistance, broad adhesion spectrum) and polyurethane (mechanical strength, paintability) — without their disadvantages (silicone: not paintable, corrosion on some metals; PU: isocyanates, often problematic indoors). SMP adhesives are solvent-, isocyanate-, and silicone-free, paintable, corrosion-resistant, and adhere to most substrates without a primer — except PE, PP, PTFE, and silicones.

HM21 adheres to metals (aluminum, stainless steel, steel), powder-coated and painted surfaces, galvanized/anodized/chromated/zinc-coated substrates, many plastics, ceramics, stone, concrete, crepi, wood, and glass. Not suitable for: PP, PE, PTFE (Teflon), silicones, and bitumen substrates. For critical material pairings, we recommend a preliminary test or application with a primer (V40 for smooth, V21 for absorbent substrates).

Store in the unopened original container in a dry, cool place — typically between +5 and +30 °C. Consult the Safety Data Sheet (SDS) before use. Observe the expiry date on the packaging. Use opened cartridges quickly — skin formation in the nozzle will block further application.

In the comparison table above, you will find related Merbenit products with different properties—different hardness, pot life, elongation at break, or special certifications (IMO, EN 45545-2, FMVSS 212, ISEGA, Minergie-ECO). If you are unsure which product is best for you, we would be happy to advise you—contact SILITECH with your specific application (substrate pairing, desired hardness, processing workflow, certification requirements).

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Product specifications

Product information
Container 290ml cartridge or 600ml bag
Tensile strength approx. 2.5 N/mm²
Temperature range (°C) -40 °C to +90 °C
consistency Stable, ≤ 3 mm
Performance at final strength
Elongation at break approximately 350%
Physical properties
Color black or white or grey
density 1.52 g/cm³
Hardness (Shore A) 45
Chemical group Silane-modified polymer
Cured layer thickness after 24 hours ≥ 3.0 mm
curing technique Moisture-curing
Uncategorized
Processing temperature +5 °C to +40 °C
Tension at 100% elongation approx. 1.6 N/mm²
Change in volume ≤ 5%
Number of components 1K
Keywords
Keywords
MS Polymer Universal Automatic Dispensing General Industry and Manufacturing Construction Metal Plastic Low Odor Solvent-Free Silicone- Free Isocyanate-Free Automotive Elastic Merbenit Accessories Spray Guns Sealant Mechanical Engineering

Documents and datasheets

Safety Data Sheets (SDS) and Technical Data Sheets (TDS) are available for download: