TEROSON MS 939

LOCTITE MS 939

Color:Black; Gray; White
Cure rate:3.0 hr.
Elongation, at break:250.0 %
FEA (finite element analysis):Finite strain
Full cure time:24.0 hr.
Key characteristics:Thixotropic
Physical form:Paste
Tensile strength, ISO 37:3.0 MPa

Overview

LOCTITE MS 939 (marketed under the TEROSON® MS 939 name by Henkel) is a gun-grade, one-component adhesive/sealant based on silane-modified polymer (SMP). It cures with ambient humidity to form an elastic, durable thermoset suitable for both bonding and seam/joint sealing.

Supplied as a pasty, thixotropic material in cartridges or foil packs, MS 939 is sag-resistant, giving high position tack after parts are brought together. It is free of solvents, isocyanates, silicones and PVC, offers good adhesion to many metals and plastics, and is compatible with suitable paint systems. The product is available in white, off-white, grey and black.

Because of its combination of strength, elasticity, UV/weathering resistance and damp-heat durability, MS 939 is widely used for vehicle and caravan manufacture, general metal construction, electrical and HVAC applications, and other industrial assemblies where long-term elastic sealing is required.

Key Features & Benefits

All values below are taken from Henkel’s published Technical Data Sheet (April 2019) and associated product literature:

  • Silane-modified polymer technology

    • Technology: silane-modified polymer, 1-part adhesive/sealant, humidity cure.

  • Thixotropic, sag-free application

    • Pasty, thixotropic consistency with no sagging in a 15 mm DIN profile, ideal for vertical and overhead seams.

  • Elastic yet strong bond line

    • Shore A hardness (ISO 868): approx. 55

    • Tensile strength (ISO 37): approx. 3.0 MPa

    • Elongation at break (ISO 37): approx. 250%

    • Stress at 100% elongation (ISO 37): approx. 1.3 MPa

  • Controlled, predictable cure

    • Skin formation time: approx. 4–10 min (23 °C / 50% RH)

    • Cure rate: approx. 3 mm / 24 h (23 °C / 50% RH)

  • Thermal and environmental resistance

    • Density: approx. 1.5 g/cm³ (all listed colours)

    • In-service temperature range: –40 °C to +100 °C

    • Short-term exposure (up to 1 h): 120 °C

    • Volume change (DIN 52451): < 2%

  • UV, weathering & damp-heat tested

    • UV resistance: no significant changes after 6 weeks dry UV (Osram Vitalux 300 W, 25 cm).

    • QUV resistance: no significant changes after 6 weeks (QUV weatherometer per DIN 53384-A).

    • Damp-heat durability: 1,000 h at 85 °C / 85% RH per IEC 61215 / 61646 clause 10.13.

  • Formulation advantages

    • Odour: characteristic (non-solvented SMP system).

    • Free of solvents, isocyanates, silicones and PVC.

    • Compatible with suitable paint systems and designed for both interior and exterior use.

Typical Applications

According to Henkel’s TDS and official marketing information, TEROSON / LOCTITE MS 939 is recommended for:

  • Vehicle & caravan manufacture

    • Elastic bonding of metals and plastics, e.g. side panelling and roof skin bonding.

    • Interior and exterior seam and joint sealing on body structures.

  • Rail & container construction

    • Seam/joint sealing in railway carriages, containers and general metal construction.

  • Industrial equipment & HVAC

    • Elastic sealing in electrical enclosures, plastic housings, air-conditioning and ventilation systems.

  • General metal and plastic assemblies

    • Where a combination of elasticity, strength, sag resistance and UV/weather resistance is needed.

Key Technical Data

All values below are taken directly from Henkel’s TEROSON MS 939 Technical Data Sheet (April 2019, standard climate ISO 291: 23 °C / 50 % RH):

General

  • Technology: Silane-modified polymer

  • Product type: Adhesive/Sealant

  • Components: One-component

  • Cure mechanism: Humidity

  • Appearance (colours): White, off-white, grey, black

  • Consistency: Pasty, thixotropic

  • Odour: Characteristic

Physical & Mechanical

  • Density (white, off-white, grey, black): approx. 1.5 g/cm³

  • Sag resistance: no sagging (DIN profile 15 mm)

  • Skin formation time: approx. 4–10 min

  • Cure rate: approx. 3 mm / 24 h

  • Shore A hardness (ISO 868): approx. 55

  • Tensile strength (ISO 37): approx. 3.0 MPa

  • Elongation at break (ISO 37, 200 mm/min): approx. 250 %

  • Stress at 100% elongation (ISO 37): approx. 1.3 MPa

  • Volume change (DIN 52451): < 2 %

Environmental & Thermal

  • UV resistance: no significant changes after 6 weeks dry UV (Osram Vitalux 300 W, 25 cm)

  • QUV resistance: no significant changes after 6 weeks (QUV, DIN 53384-A)

  • Damp heat test (IEC 61215 / 61646, 10.13): durability given after 1,000 h at 85 °C / 85 % RH

  • Application temperature: 5 to 40 °C

  • In-service temperature range: –40 to +100 °C

  • Short exposure (up to 1 h): 120 °C

Storage (unopened original packaging)

  • Frost-sensitive: No

  • Recommended storage temperature: 10 to 25 °C

  • Shelf life: 12 months

Surface Preparation & Application Guidance

Summarised from Henkel’s directions for use:

  1. Pre-treatment

    • Substrates must be clean, dry and free of oil and grease.

    • Depending on the surface, it may be necessary to roughen and/or use a primer or adhesion promoter for best adhesion.

    • Any mould release agents on plastics must be thoroughly removed.

    • Because paints (especially powder coatings) and substrates vary, application trials are required.

    • Henkel recommends cleaners such as TEROSON VR 10 or TEROSON SB 450 for surface preparation.

  2. Application

    • 290 mL cartridges: apply with TEROSON hand or air-pressure pistols.

    • 310 mL and 570 mL foil cartridges: use corresponding FK hand or FK air-pressure pistols.

    • For compressed air application, 2–5 bar is typically required.

    • Low material temperature increases viscosity and lowers extrusion rate; bring material to room temperature before use.

    • MS 939 can also be dispensed from hobbocks or drums via high-pressure pumps with follower plates, following Henkel’s separate application directions.

  3. Cleaning

    • For uncured material on tools and equipment, Henkel recommends TEROSON VR 30 or TEROSON VR 10.

Always consult the latest Henkel TDS and SDS for full and region-specific instructions.

FAQs

Q1. What type of product is LOCTITE / TEROSON MS 939?
It is a gun-grade, one-component adhesive/sealant based on silane-modified polymer that cures with humidity to an elastic product, suitable for bonding and seam/joint sealing.

Q2. Which colours are available?
According to Henkel’s data sheet, MS 939 is supplied in white, off-white, grey and black.

Q3. How fast does it skin and cure?
At 23 °C and 50 % relative humidity, the skin forms after approximately 4–10 minutes, and the typical cure rate is about 3 mm per 24 hours. Deeper joints require more time.

Q4. What mechanical properties does the cured sealant have?
Typical values (ISO 37 / ISO 868) are: Shore A ≈ 55, tensile strength ≈ 3.0 MPa, elongation at break ≈ 250 %, and stress at 100 % elongation ≈ 1.3 MPa.

Q5. What temperature range can MS 939 withstand in service?
Henkel lists an in-service temperature range from –40 °C to +100 °C, with short-term exposure up to 120 °C (up to 1 hour).

Q6. Is it suitable for outdoor use and UV exposure?
Yes. MS 939 shows no significant changes after 6-week UV and QUV tests and is recommended for interior and exterior applications.

Q7. Does LOCTITE / TEROSON MS 939 contain solvents or isocyanates?
No. The product is described as free of solvents, isocyanates, silicones and PVC, and it is non-corrosive to many substrates.

Q8. Which applications are highlighted by Henkel?
Henkel specifically mentions elastic bonding of metals and plastics (such as vehicle and caravan side panels and roof skins) and elastic seam/joint sealing in vehicle bodies, caravans, railway carriages, containers, general metal construction, plus the electrical, plastics, air-conditioning and ventilation industries.

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