COOLTHERM UR-388

Harmonization Code : 3506.91.90.99 | Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg ; Adhesives based on polymers of headings 3901 to 3913 or on rubber; Other ; Other

COOLTHERM UR-388

Main features

  • UL 94 V-0 Classification
  • 0.7 W/(m K) Thermal Conductivity
  • 15.0 kV/mm Dielectric Strength

Product Description

CoolTherm UR-388 Flame Retardant Urethane Encapsulant is a two-part, black, semi-flexible urethane system for encapsulating and casting electrical and electronic assemblies. Resin and hardener mix 100:20 by weight, producing a typical mixed viscosity of 6,000 cP at 25 deg C and a 30-minute working time. Cure schedules are 24 hours at 25 deg C or 6 hours at 60 deg C. Typical cured properties include 90 Shore A hardness, 0.7 W/(m K) thermal conductivity, and 15.0 kV/mm dielectric strength. The encapsulant carries a UL 94 V-0 flammability classification and has a stated service-temperature range of -55 to +130 deg C.

Key features

  • Cured flammability classification: The cured encapsulant carries a UL 94 V-0 flammability classification.
  • Cured thermal conductivity: Typical cured thermal conductivity is 0.7 W/(m K).
  • Cured dielectric strength: Typical cured dielectric strength is 15.0 kV/mm.

Applications

Encapsulating and casting electrical and electronic assemblies where flame retardancy, low stress, and thermal conductivity are required.

Product Family

COOLTHERM UR-388

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TDS, SDS & Technical Documents

Technical Specifications

General Properties
Appearance
Appearance at room temperature.
Black Liquid
Component System
Describes the number of components that must be supplied, mixed, or activated before application or cure.
Two Part (Resin / Hardener)
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.
1.47
Thermal Properties
Thermal Conductivity
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance. Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
0.7 W/m.K
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.
50 %
Electrical Properties
Dielectric Strength
Dielectric strength is measured in kV per mm and is calculated by the Breakdown voltage divided by the thickness of the tested material. Those two properties go hand in hand and while Breakdown voltage is always thickness dependent, dielectric strength is a general material property. As an example, the dielectric strength of Polyimide is 236 kV/mm. If we place 1mm of Polyimide between two electrodes, it will act as an insulator until the voltage between the electrodes reaches 236 kV. At this point it will start acting as a good conductor, causing sparks, potential punctures and current flow.
15.0 kV/mm
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.
7 x 10¹⁵ Ohms⋅cm

Additional Information

Technical properties

As-supplied / before-processing properties

UR-388 is supplied as a two-component resin-and-hardener system; mixed values apply after the 100:20 by-weight combination.

PropertyValueUnitMethod / condition
Appearance, mixedBlackTypical
Viscosity, mixed6,000cPTypical; 25 deg C
Mix ratio, resin:hardener100:20by weightBefore application
Working time30minMixed material; 25 deg C
Technical properties

Cured encapsulant properties

Cure options are 24 hours at 25 deg C or 6 hours at 60 deg C.

PropertyValueUnitMethod / condition
Hardness90Shore ATypical
Dielectric strength15.0kV/mmTypical; 388 V/mil
Thermal conductivity0.7W/(m K)Typical
Service-temperature range-55 to +130deg CSupplier-stated range
Flammability classificationUL 94 V-0Exact product classification

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