Name: STPE Low-Modulus Sealant Polymer SLM-20
Brand: Coatingsink
SKU: stpe-low-modulus-polymer-slm
Availability: InStock

Question 1

What distinguishes SLM-20 as a low-modulus STPE compared to standard silane-terminated sealants?

Accepted Answer

SLM-20 uses a high-molecular-weight polyether backbone (Mn ~12,000 g/mol) with a low silane end-group density (~1.5 mmol/g), reducing crosslink density after atmospheric moisture cure. This yields Shore A 15–25 and >400% elongation, making it suitable for dynamic movement joints accommodating displacement of ±25% or more.

Question 2

Does SLM-20 require a primer for adhesion on concrete, aluminium, or glass?

Accepted Answer

No. SLM-20 achieves ≥1.5 MPa cohesive-failure adhesion on clean concrete, anodised aluminium, and glass without a primer, due to silanol interaction with hydroxylated surfaces during cure. For porous or heavily contaminated substrates a silane-based adhesion promoter is recommended for long-term durability.

Question 3

What are the skin-over time and through-cure schedule for SLM-20 at standard conditions?

Accepted Answer

At 23°C/50% RH, skin-over time is 20–40 minutes. Through-cure proceeds at approximately 2 mm/day; a 10 mm joint profile reaches full mechanical properties within 7 days. At 5°C, cure rate drops to ~1 mm/day—allow extended conditioning time in cold or low-humidity environments.

Tensile Strength	0.8–1.2 MPa
Viscosity (23°C)	20,000–35,000 mPa·s
Elongation at Break	>400%
Shore A Hardness (cured)	15–25
Silane End-Group Content	~1.5 mmol/g

STPE Low-Modulus Sealant Polymer SLM-20

Specifications

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