LOCTITE SI 5248

Harmonization Code : 2901.10.00.00 | Acyclic hydrocarbons; Saturated

LOCTITE SI 5248

Main features

  • UV/Shadow-Area Dual Cure
  • Thixotropic Low-Migration Sealing
  • Flexible Electrical Insulation

Product Description

LOCTITE SI 5248 Light-Cure Silicone Sealant is a one-part, thixotropic alkoxy silicone for gasketing and sealing assemblies that need a flexible, low-migration material. UV light develops functional strength rapidly in exposed regions, while atmospheric moisture cures areas hidden from the light. The straw-colored material skins in about 11 minutes and becomes tack-free in about 14 minutes where UV is absent. Full performance develops over 72 hours. Under the specified cure, the silicone reaches at least 135% elongation, at least Shore A 25 hardness, and volume resistivity of 8.3 x 10^13 ohm-cm.

Key features

  • Dual UV and moisture cure: Light cures exposed regions while atmospheric moisture cures shadowed areas.
  • Thixotropic low-migration sealing: Reduced liquid migration helps retain material after application.
  • Flexible electrical insulation: The specified cure provides at least 135% elongation and 8.3 x 10^13 ohm-cm volume resistivity.

Applications

Applications include flexible gasketing and sealing of glass, ceramics, metals, and compatible plastics.

Product Family

LOCTITE SI 5248

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Appearance
Appearance at room temperature.
Straw colored liquid
Chemistry Type
Alkoxy silicone
Component System
Describes the number of components that must be supplied, mixed, or activated before application or cure.
1K
Solids
≥95 %
Specific Gravity
Specific gravity (SG) is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume. For liquids, the reference substance is almost always water (1), while for gases, it is air (1.18) at room temperature. Specific gravity is unitless.
1.05
Physical Properties
Tack-Free Time
≤14 minutes
Viscosity
Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application
50,000 to 80,000 mPa.s
Mechanical Properties
Elongation
Elongation is the process of lengthening something. It is a percentage that measures the initial, unstressed, length compared to the length of the material right before it breaks. It is commonly referred to as Ultimate Elongation or Tensile Elongation at break.
≥135 %
Electrical Properties
Volume Resistivity
Volume resistivity, also called volume resistance, bulk resistance or bulk resistivity is a thickness dependent measurement of the resistivity of a material perpendicular to the plane of the surface.
8.3×10^13 Ohms⋅cm
Chemical Properties
Water Absorption
0 %

Additional Information

Technical properties

As-supplied properties

Property Value Unit Method / condition
Appearance Straw-colored liquid As supplied
Specific gravity 1.05 As supplied
Solids / non-volatile content At least 95 % Typical property
Viscosity 50,000 to 80,000 mPa s (cP) Brookfield RVT, spindle 6, 2.5 rpm, 25 deg C
Technical properties

Cured properties

Mechanical values use the specified light cure plus ambient post-cure; other rows retain their listed test conditions.

Property Value Unit Method / condition
Shore hardness At least 25 Shore A ISO 868; 70 mW/cm^2 for 60 s per side plus 3 days at 22 deg C / 50 +/- 5% RH
Elongation At least 135 % ISO 37; same cure as Shore hardness
Tensile strength At least 1 N/mm^2 ISO 37; same cure as Shore hardness
Tear strength At least 1.7 N/mm ISO 34-1, Die B; same cure as Shore hardness
Water absorption 0 % ISO 62, 24 h in water at 22 deg C; 40 mW/cm^2 for 60 s per side plus 7 days at 22 deg C / 50% RH
Volume resistivity 8.3 x 10^13 ohm-cm IEC 60093; cured material
Compression set at 22 deg C 6 % ASTM D395, Method B, 70 h
Water vapor transmission rate 0.455 g/(h m^2) ASTM E96

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