EE Device Comprising a Composite Polycarbonate Element Having High CTI
AssigneeCovestro Deutschland AG
InventorsMatthias Knaupp, Tim Hungerland, Marius Nolte, Constantin Schwecke
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Abstract
The invention relates to an EE device including depending on the operating voltage applied, different distance ranges between the electrical conductors, the distances being so small that already the material used between the electrical conductors results in a very high comparative tracking index. Surprisingly, this material is a polycarbonate-based material the comparative tracking index of which is significantly increased when relatively small amounts of fluorine-containing anti-dripping agent and phosphorus-based retardant are added.
Claims13
An EE component, comprising
- a first electrical conductor and a second electrical conductor at a first distance d1 and a second distance d2 with respect to one another,
- which are connected via a thermoplastic composition Z which is in direct contact with the first electrical conductor and the second electrical conductor,
- wherein the distance d1 is the shortest distance between the first electrical conductor and the second electrical conductor along the surface of the thermoplastic material M and
- wherein the distance d2 is the shortest distance between the first electrical conductor and the second electrical conductor through the air, wherein d2 is selected in such a way that at the respective operating voltage a sparkover through the air is prevented,
- wherein d1, at the operating voltage U listed below, is:
- d
-
- 1
-
- i
-
- (
- 0
-
- V
- ≤
- U
- ≤
- 250
-
- V
- )
- :
- 1.3
- mm
-
- to
- <
- 2.5
- mm
-
- d
-
- 1
-
- ii
-
- (
- 250
-
- V
- <
- U
- ≤
- 500
-
- V
- )
- =
- 2.5
- mm
-
- to
- <
- 5.
- mm
-
- d
-
- 1
-
- iii
-
- (
- 500
-
- V
- <
- U
- ≤
- 1000
-
- V
- )
- =
- 5.
- mm
-
- to
- <
- 10.
- mm
- .
- and wherein the thermoplastic composition Z comprises the following components:
- A) at least 80% by weight of aromatic polycarbonate based on bisphenol A,
- B) 0.25% by weight to 5% by weight of fluorine-containing anti-drip agent containing polytetrafluoroethylene,
- C) at least 2% by weight of phosphorus-containing flame retardant,
- wherein the quotient of the amount of phosphorus-containing flame retardant and
- the amount of polytetrafluoroethylene is ≤40 and
- wherein, when the phosphorus-containing flame retardant is
- b1) an organophosphate,
- the amount of phosphorus-containing flame retardant is 2% to 12% by weight,
- and, when the phosphorus-containing flame retardant is
- b2) a phosphazene,
- the amount of phosphorus-containing flame retardant is 2% to 9% by weight,
- and wherein the thermoplastic composition Z is free of flame retardants selected from the group of alkali metal, alkaline earth metal or ammonium salts of aliphatic or aromatic sulfonic acid, sulfonamide or sulfonimide derivatives.
A method for achieving a CTI, determined in accordance with IEC 60112:2009, of 600 V of an aromatic polycarbonate-based composition containing at least 80% by weight of aromatic polycarbonate, based on bisphenol A, wherein the stated amounts are based on the resulting overall composition, by providing the combination of:
- 0.25 % by weight to 5% by weight of fluorine-containing anti-drip agent containing polytetrafluoroethylene,
- at least 2% by weight of phosphorus-containing flame retardant,
- wherein the ratio of phosphorus-containing flame retardant to PTFE is ≤40 and
- wherein, when the phosphorus-containing flame retardant is
- b1) an organophosphate,
- the amount of phosphorus-containing flame retardant is 2% to 12% by weight,
- and, when the phosphorus-containing flame retardant is
- b2) a phosphazene,
- the amount of phosphorus-containing flame retardant is 2% to 9% by weight.
Dependencies are inferred from the claim text.