Basic material: fiberglass

Fiberglass is a laminated pressed composite material. It is made of two or more parallel layers, impregnated with a polymer (thermosetting) resin. It is easily stamped/machined. Depending on the purpose, the basic material can be either structural or electrotechnical.

Advantages of application

  • Safe, environmentally friendly material.
  • High mechanical/dielectric values.
  • Excellent resistance to aggressive chemical media, moisture and temperature fluctuations.
  • Durable: average service life - 20 years.

Application area

It is used to produce both double-layer and MPB of high strength in the following areas:

  • Metal industry
  • Shipbuilding
  • Electrical and radio engineering
  • Aviation equipment and components for missiles

Basic types

Standard - FR-4

The vitrification temperature is 130 °C. There is UV protection - UV blocking. It is the most common type of fiberglass, low-cost.

With high temperature values of vitrification

The vitrification temperature varies from 170˚ to 200˚. Unlike standard FR-4, high-temperature dielectric substrates have via holes of higher quality (by 1.8%) and more tolerance on thickness (by 3%). The total quantity of resin spots is reduced by 12%, compared to standard materials. They are easy-processing and resistant to chemical reagents.

Halogen-free

Basic halogen-free materials are compatible with lead-free tinning and soldering. Flammability class: UL94-V0.

Technical characteristics

The standard fiberglass of FR-4 specification is 1.6 mm thick and it contains 8 prepreg layers. The fourth (central) layer has the manufacturer's logo, and its colour indicates the assignment of a flammability class. For example, blue colour indicates the flammability class UL94-HB (the mounting substrate is not fireproof), red - UL94-V0 (fireproof material).

The real colour of FR-4 is transparent, green tint appears on the printed circuit board only after the application of the soldermask.

Parameters

Standard

Halogen-free

High-temperature

Specific volume resistance, MΩ / cm

1,9∙108

107-5∙107

1015-5∙1015

Specific surface resistance, MΩ

3,8∙107

108-5∙108

1014-5∙1014

Index of the dielectric constant

4,8

5,2

4,7

Dispersion coefficient

0,018

0,01

0,015

Index of thermal resistance at soldering 288 °C, sec

Not more than 20

Less than 120

Peel resistance coefficient, kN/m

1,43-1,81

1,86

1,96

Dielectric breakdown, HF

Not more than 50

Bending strength, N mm2

490

Insulation resistance

107-108

1013-1014

Vitrifaction temperature, °C

130

170-200

 

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