EP0331276A2

Resin compositions for moulding black shielding materials.

Abstract

Resin compositions for moulding black shielding materials of substantially black appearance, which when used as a black shielding casing or cover for electrical equipment prevent visibility of the interior, but shine red when a pilot lamp is on by virtue of transmission of visible light substant­ially only in the wavelength range 700 to 780 nm.

EP0331276A2, drawing sheet 1
Sheet 1 of 2

Term

Term ended

Projected expiry passed 6 January 2009, 17.7 years ago.

  1. Priority
  2. Filed
  3. Published
  4. Projected expiry
  5. Today

8 claims: 3 independent, 5 dependent

  1. 1
    A resin composition for moulding a black shielding material of substantially black appearance, characterized in that it comprises a mixture of one or more synthetic resins of good light transmission and a plurality of dyes which can be formed into a black shielding material having an L value of 15 or less and an (a²+ b²) 1/2 value of 25 or less according to the lab colour system, and showing an average light transmission in the wavelength range 700 to 780 mn of at least 35%.
  2. 5
    A resin composition according to any one of claims 2 to 4, characterised in that the said plurality of dyes additionally includes at least one dye of other than red or green colour which transmits visible light in the wavelength range 700 to 780 nm and absorbs visible light at certain wavelengths in the range 700 nm or less to which the said dye components (a) and (b) are transparent.
  3. 7
    A moulded black shielding material of substant­ially black appearance, characterised in that it is formed from a resin composition as claimed in any one of claims 1 to 6, has an L value of 15 or less and an (a² + b²) 1/2 value of 25 or less according to the lab colour system, and shows an average light transmission in the wavelength range 700 to 780 nm of at least 35%.
  4. 8
    A black shielding casing or covering of substant­ially black appearance for electrical equipment, characterised in that it is formed from a resin composition as claimed in any one of claims 1 to 6, has an L value of 15 or less and an (a² + b²) 1/2 value of 25 or less according to the lab colour system, and shows an average light transmission in the wavelength range 700 to 780 nm of at least 35%.