| (19) |
 |
|
(11) |
EP 0 587 453 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
24.08.1994 Bulletin 1994/34 |
| (43) |
Date of publication A2: |
|
16.03.1994 Bulletin 1994/11 |
| (22) |
Date of filing: 13.09.1993 |
|
| (51) |
International Patent Classification (IPC)5: H01B 3/44 |
|
| (84) |
Designated Contracting States: |
|
ES FR GB IT |
| (30) |
Priority: |
11.09.1992 BR 9203610
|
| (71) |
Applicant: PIRELLI CABOS S/A |
|
Sao Paulo - SP (BR) |
|
| (72) |
Inventors: |
|
- Goncalves, Jose Francisco
Sao Paulo (BR)
- Picoli, Valter Marques
Sao Paulo (BR)
|
| (74) |
Representative: Smith, Philip Antony |
|
REDDIE & GROSE
16 Theobalds Road
London WC1X 8PL
London WC1X 8PL (GB) |
|
| |
|
| (54) |
Insulation compositions of moisture cross-linked polyethylene (XPLE) for use in low
tension power cables |
(57) To reduce contraction of the insulation which may occur at an operating temperature
of 130°C, the polyethylene that is usually employed for the application of the "Sioplas"
cross-linking process is modified with polypropylene (PP).
The polypropylene presents a softening point between 155 and 165°C, which guarantees,
up to 130°C, the dimensional stability of the extruded material.
The mixture of the PP with low density polyethylene (LDPE) or low density linear polyethylene
(LLDPE) or co-polymeric polyethylene of ethylene vinyl acetate (EVA) in an adequate
concentration is the solution for the contraction problem.