Title of Invention

LOW VOLTAGE POWER CABLE AND PROCESS FOR PRODUCING THE SAME

Abstract The present invention relates to a low voltage power cable comprising an insulation layer with a density below 1100 kg/m3 which comprises a polyolefin comprising 0.02 to 4 mol% of a compound having polar groups and further comprises a compound having hydrolysable silane groups and includes 0.0001 to 3 wt.-% of a silanol condensation catalyst. Furthermore, the present invention relates to a process for the production of said low voltage power cable.
Full Text The present invention relates to a low voltage power cable comprising an
insulation layer which comprises a polyolefin having polar groups,
hydrolysable silane groups and includes silanol condensation catalyst to a
process for the production thereof and to the use of said polyolefin in the
production of an insulation layer for a low voltage power cable.
Electric power cables for low voltages, i.e. voltages of below 6 kV, usually
comprise an electric conductor which is coated with an insulation layer.
Such a cable will in the following be referred to as single wire cable.
Optionally, two or more of such single wire cables are surrounded by a
common outermost sheath layer, the jacket.
The insulation layer of low voltage power cables usually is made of a
polymer composition comprising a polymer base resin, such as a
polyolefin. A material commonly used as a base resin is polyethylene.
Furthermore, in the final cable the polymer base resin usually is cross-
linked.
In addition to the polymer base resin, polymer compositions for insulation
layers of low voltage power cables usually contain further additives to
improve the physical properties of the insulating layer of the electric cable
and to increase its resistance to the influence of different surrounding
conditions. The total amount of the additives is generally about 0.3 to 5%
by weight, preferably about 1 to 4% by weight of the total polymer
composition. The additives include stabilizing additives such as
antioxidants to counteract decomposition due to oxidation, radiation, etc.;
lubricating additives, such as stearic acid; and cross-linking additives such
as peroxides to aid in the cross-linking of the ethylene polymer of the
insulating composition.

In contrast to low voltage ( 6 to 68 kV)
and high voltage (>68 kV) power cables are composed of a plurality of
polymer layers extruded around an electric conductor. The electric
conductor is coated first with an inner semiconductor layer followed by an
insulating layer, and then an outer semiconductive layer all based on
crosslinked polyethylene. Outside this cable core layers consisting of water
barriers, metallic screens, bedding (polymer layer making the cable round)
and on the outside a polyolefin based sheath layer are commonly applied.
The thickness of the insulation layer of these cables is in the range of 5 to
25 mm.
As in low voltage power cables the insulation layer is usually much thinner,
e.g. 0.4 to 3 mm, and directly coated onto the electric conductor and the
insulation layer being the only layer surrounding each single conducting
core, it is of great importance that the insulation layer must have good
mechanical properties, like elongation at break and tensile strength at
break. However, when this thin polyolefin layer is extruded towards a cold
conductor, its mechanical properties are heavily deteriorated. For this
reason, when extruding insulation layers comprising polyolefins on
conductors, usually preheated conductors are used, this, however, being a
disadvantage compared to materials, as e.g., PVC. The mechanical
properties of the thin polyolefin layer are furthermore negatively affected
by plastisizer migrating into it from the surrounding bedding and sheathing
layers applied outside the cable core(s), which still commonly is PVC
based in low voltage cables.
Furthermore, cable joints between low voltage power cables preferably are
formed in such a way that, after stripping off part of the insulation layer at
the end of both cables to be joined and connecting the electric conductors, a
new insulation layer covering the joint conductors is often formed of a
polyurethane polymer. Accordingly, it is important that the polymer
composition of the original insulation layer shows a good adhesion to the
polyurethane polymer used for restoring the insulation layer so that the
layer is not disrupted even under mechanical stress at the cable joints.
Still further, as insulation layers of low voltage power cables usually are
formed by direct extrusion onto a conductor, it is important that the

polymer composition used for the insulation layer shows good extrusion
behavior and, after extrusion, retains its good mechanical properties.
WO 95/17463 describes the use of a sulphonic acid as a condensation
catalyst added in a masterbatch which comprises 3-30% by weight of LD,
PE or EBA.
WO 00/36612 describes a Medium/High voltage (MV/HV) power cable
with good electrical properties, especially long time properties. These
MV/HV cables always have an inner semiconductive layer and outside that
layer an insulation layer. The adhesion between these layers is always good
since they are made of essentially the same material, i.e. polyethylene
compounds. In contrast, the present invention is directed to a low voltage
power cable and inter alia solves the problem of adhesion of the insulation
layer to the conductor and problems associated with extruding directly on a
conductor.
WO 02/88239 teaches how additives shall be chosen to an acid
condensation catalyst.
US 5,225,469 describes polymer compositions based on ethylene-vinyl
ester and ethylene-alkyl acrylate copolymers which can be crosslinked to
provide insulation coatings for wire and cable products.
EP 1 235 232 teaches that the coating layer of cables based on a
composition material comprises polar groups and inorganic material.
Accordingly, it is the object of the present invention to provide a low
voltage power cable with an insulation layer which shows good mechanical
properties and, at the same time, shows good adhesion to polyurethane
polymers and after extrusion retains its good mechanical properties. It is a
further object of the invention to provide a low voltage power cable with an
insulation layer having an improved resistance to deterioration of
mechanical properties caused by migration of plasticisers from PVC into
the layer.
The present invention is based on the finding that such a low voltage power
cable can be provided if the insulation layer contains a polymer with 0.02

to 4 mol% of a compound having polar groups and further comprising a
compound having hydrolysable silane groups and includes 0.0001 to 3 wt-% of
a silanol condensation catalyst.
The present invention therefore provides a low voltage power cable
comprising an insulation layer with a density of below 1100 kg/m3 which
comprises a polyolefin comprising 0.02 to 4 mol% of a compound having
polar groups, and further comprises a compound having hydrolysable silane
groups and includes 0.0001 to 3 wt.-% of a silanol condensation catalyst.
It has surprisingly been found that an insulation layer which comprises a
polyolefin comprising 0.02 to 4 mol% of a compound having polar groups
and further comprises a compound having hydrolysable silane groups and
includes 0.0001 to 3 wt-% of a silanol condensation catalyst decisively
improves the adhesion towards polyurethane polymers, so that durable
joints between low voltage power cables according to the invention can be
made with polyurethane polymer fillers.
At the same time, the insulation layer of the cable fulfills the demanding
requirements for the mechanical properties of a low power voltage cable. In
particular, the elongation at break is improved. LV cables are often
installed in buildings. Single wire cables usually are installed in a conduit
and during installation the single wire cables are drawn through long
conduits. Sharp corners and especially other installations could cause
damages to the insulation layer of the cable. The low voltage power cable
according to the invention due to its improved elongation at break
effectively prevents such breaks during installation.
Furthermore, the insulation layer shows an improved extrusion behavior
insofar as no preheating or a smaller degree of preheating of the conductor
is necessary during the extrusion process for obtaining good mechanical
properties of the final insulation layer.
Finally, the insulation layer retains good mechanical properties when aged
with PVC.
The low voltage power cable according to the invention has carefully been
optimized in regard to all required parameters. The combination of

mechanical strength, with low absorption of PVC plasticicers are the key
parameters. Another important aspect of this invention is the low amount of
polar groups. This is especially important to low voltage power cables,
since they must be very cost efficient. They are usually made with only one
combined insulation layer and jacketing layer which is mostly quite thin. It
cannot be stressed enough how important it is that this layer has high
electrical resistance and good mechanical strength. This is accomplished
with the low amount of polar groups. Another aspect of the invention is
making a compound with good abrasion properties. If the composition
comprises a high amount of copolymers the composition will be softer.
This means that the abrasion will be lower. Abrasion is important in
industrial applications with, for example, high degrees of vibrations. This is
another reason why the amount of polar groups must be low.
The expressing "a compound having polar groups" is intended to cover
both the case where only one chemical compound with polar groups is used
and the case where a mixture of two or more such compounds is used.
Preferably, the polar groups are selected from siloxane, amide, anhydride,
carboxylic, carbonyl, hydroxyl, ester and epoxy groups.
The said polyolefin may for example be produced by grafting of a
polyolefin with a polar-group containing compound, i.e. by chemical
modification of the polyolefin by addition of a polar group containing
compound mostly in a radical reaction. Grafting is e.g. described in US
3,646,155 and US 4,117,195.
It is, however, preferred that said polyolefin is produced by
copolymerisation of olefinic monomers with comonomers bearing polar
groups. In such cases, the complete comonomer is designated by the
expression "compound having polar groups". Thus, the weight fraction of
the compound having polar groups in a polyolefin which has been obtained
by copolymerization may simply be calculated by using the weight ratio of
the monomers and comonomers bearing polar groups that have been
polymerised into the polymer. For example, where said polyolefin is
produced by copolymerization of olefin monomers with a vinyl compound
comprising a polar group, also the vinyl part, which after polymerization

forms part of the polymer backbone, contributes to the weight fraction of
the "compound having polar groups".
As examples of comonomers having polar groups may be mentioned the
following: (a) vinyl carboxylate esters, such as vinyl acetate and vinyl
pivalate, (b) . (meth)acrylates, such as methyl(meth)acrylate,
ethyl(meth)acrylate, butyl(meth)acrylate and hydroxyethyl(meth)acrylate,
(c) olefinically unsaturated carboxylic acids, such as (meth)acrylic acid,
maleic acid and fumaric acid, (d) (meth)acrylic acid derivatives, such as
(meth)acrylonitrile and (meth)acrylic amide, and (e) vinyl ethers, such as
vinyl methyl ether and vinyl phenyl ether.
Amongst these comonomers, vinyl esters of monocarboxylic acids having 1
to 4 carbon atoms, such as vinyl acetate, and (meth)acrylates of alcohols
having 1 to 4 carbon atoms, such as methyl (meth)acrylate, are preferred.
Especially preferred comonomers are butyl acrylate, ethyl acrylate and
methyl acrylate. Two or more such olefinically unsaturated compounds may
be used in combination. The term "(meth)acrylic acid" is intended to
embrace both acrylic acid and methacrylic acid.
Preferably, said polyolefin comprises at least 0.05 mol, more preferably 0.1
mol% and still more preferably 0.2 mol%, of a polar compound having
polar groups. Further, the polyolefin compound comprises not more than
2,5 mol%, more preferably not more than 2.0 mol%, and still more
preferably not more than 1,5 mol% of a polar compound having polar
groups.
In a preferred embodiment, said polyolefin is an ethylene homo- or
copolymer, preferably homopolymer.
The polyolefin used for the production of the insulation layer preferably is
crosslinked after the low voltage power cable has been produced by
extrusion. A common way to achieve such cross-linking is to include a
peroxide into the polymer composition which after extrusion is
decomposed by heating, which in turn effects cross-linking. Usually, 1 to 3
wt.-%, preferably about 2 wt.-% of peroxide cross-linking agent based on
the amount of polyolefin to be crosslinked is added to the composition used
for the production of the insulation layer.

However, it is preferred to effect cross-linking by way of incorporation of
cross-linkable groups to the polyolefin comprising a compound having
polar groups used in the production of the insulation layer.
Hydrolysable silane groups may be introduced into the polymer either via
grafting, as e.g. described in US 3,646,155 and US 4,117,195, or preferably
via copolymerization of silane groups containing comonomers.
The comonomer with silane groups is designated by the expression
"compound having silane groups".
Preferably, the silane group containing polyolefin has been obtained by
copolymerization. In the case of polyolefins, preferably polyethylene, the
copolymerization is preferably carried out with an unsaturated silane
compound represented by the formula

wherein
R1 is an ethylenically unsaturated hydrocarbyl, hydrocarbyloxy or
(meth)acryloxy hydrocarbyl group,
R2 is an aliphatic saturated hydrocarbyl group,
Y which may be the same or different, is a hydrolysable organic group and
q is 0, 1 or 2.
Special examples of the unsaturated silane compound are those wherein R1
is vinyl, allyl, isopropenyl, butenyl, cyclohexanyl or gamma-
(meth)acryloxy propyl; Y is methoxy, ethoxy, formyloxy, acetoxy,
propionyloxy or an alkyl-or arylamino group; and R2, if present, is a
methyl, ethyl, propyl, decyl or phenyl group.
A preferred unsaturated silane compound is represented by the formula


wherein A is a hydrocarbyl group having 1-8 carbon atoms, preferably 1-4
carbon atoms.
The most preferred compounds are vinyl trimethoxysilane, vinyl
bismethoxyethoxysilane, vinyl triethoxysilane, gamma-(meth)acryl-
oxypropyltrimethoxysilane, gamma(meth)acryloxypropyltriethoxysilane,
and vinyl triacetoxysilane.
The copolymerization of the olefin, e.g. ethylene, and the unsaturated
silane compound may be carried out under any suitable conditions resulting
in the copolymerization of the two monomers.
The silane-containing polymer according to the invention suitably contains
0.001 to 15% by weight of the silane group containig compound, preferably
0.01 to 5% by weight, most preferably 0.1 to 2% by weight.
Examples for acidic silanol condensation catalysts comprise Lewis acids,
inorganic acids such as sulphuric acid and hydrochloric acid, and organic
acids such as citric acid, stearic acid, acetric acid, sulphonic acid and
alkanoric acids as dodecanoic acid.
Preferred examples for a silanol condensation catalyst are sulphonic acid
and tin organic compounds.
It is further preferred mat the silanol condensation catalyst is a sulphonic
acid compound according to formula (III)

or a precursor thereof, Ar being a hydrocarbyl substituted aryl group and
the total compound containing 14 to 28 carbon atoms.
Preferably, the Ar group is a hydrocarbyl substituted benzene or
naphthalene ring, the hydrocarbyl radical or radicals containing 8 to 20
carbon atoms in the benzene case and 4 to 18 atoms in the naphthalene
case.
It is further preferred that the hydrocarbyl radical is an alkyl substituent
having 10 to 18 carbon atoms and still more preferred that the alkyl

substituent contains 12 carbon atoms and is selected from dodecyl and
tetrapropyl. Due to commercial availability it is most preferred that the aryl
group is a benzene substituted group with an alkyl substituent containing
12 carbon atoms.
The currently most preferred compounds of formula (III) are dodecyl
benzene sulphonic acid and tetrapropyl benzene sulphonic acid.
The silanol condensation catalyst may also be precursor of a compound of
formula (III), i.e. a compound that is converted by hydrolysis to a
compound of formula (III). Such a precursor is for example the acid
anhydride of the sulphonic acid compound of formula (III). Another
example is a sulphonic acid of formula (III) that has been provided with a
hydrolysable protective group as e.g. an acetyl group which can be
removed by hydrolysis to give the sulphonic acid of formula (III). The
silanol condensation catalyst is used in an amount from O.0001 to 3 wt.-%.
The preferred amount of silanol condensation catalyst is from 0.001 to 2
wt% and more preferably 0.005 to 1 weight% based on the amount of
silanol groups containing polyolefin in the polymer composition used for
the insulation layer.
The effective amount of catalyst depends on the molecular weight of the
catalyst used. Thus, a smaller amount is required of a catalyst having a low
molecular weight than a catalysts having a high molecular weight.
If the catalyst is contained in a master batch it is preferred that it comprises
the catalyst in an amount of 0.02 to 5 wt%, more preferably about 0.05 to 2
wt%.
The insulation layer of the low voltage power cable preferably has a
thickness of 0.4 mm to 3.0 mm, preferably 2 mm or lower, depending on
the application.
Preferably, the insulation is directly coated onto the electric conductor.
Furthermore, the polymer composition comprising a polyolefin comprising
a compound having polar groups and further a compound having
hydrolysable silane groups and includes a silanol condensation catalyst

used for the production of low voltage cables according to the invention
allows for the direct extrusion of the insulating layer onto the non-
preheated or only moderately preheated conductor without a deterioration
of the mechanical properties of the final insulation layer.
Therefore, the present invention also provides a process for producing a
low voltage power cable comprising a conductor and an insulation layer
with a density of below 1100 kg/m3 which layer comprises a polyolefin
comprising 0.02 to 4 mol% of a compound having polar groups which
process comprises extrusion of the insulation layer onto the conductor
which is preheated to a maximum temperature of 65 °C, preferably
preheated to a maximum temperature of 40 °C, and still more preferably
onto the non-preheated conductor.
Optionally, between the conductor and the insulation layer, a primer can be
applied.
Still further, the present invention pertains to the use of a polyolefin
comprising 0.02 to 4 mol% of a compound having polar groups in the
production of an insulation layer with a density of below 1100kg/m3 for a
low voltage power cable.
The present invention will now be further illustrated by way of examples
and the following figures:
Fig. 1 shows the tensile strength at break as a function of the preheating
temperature of the conductor for polymer A (Comp.) and polymer D, and
Fig. 2 shows the elongation at break as a function of the preheating
temperature of the conductor for polymer A (Comp.) and polymer D.
Examples
1. Compositions used for production of insulation layers
a) Polymer A (comparative) is a ethylene copolymer containing 0.23
mol% (1.25 wt%) of vinyltrimethoxysilane (VTMS), which has been
obtained by free radical copolymerisation of ethylene monomers and

VTMS comonomers. Polymer A has a density of 922 kg/m3 and an MFR2
(190 °C, 2.16 kg) of 1.00 g/10min.
b) Polymer B (comparative) is a ethylene copolymer containing 0.25
mol% (1.3 wt%) of vinyltrimethoxysilane (VTMS), which has been
obtained in the same way as polymer A. Polymer B has a density of 925
kg/m3 and an MFR2 (190 °C, 2.16 kg) of 1.1 g/lOmin.
c) Polymer C is a ethylene copolymer containing 0.25 mol% (1.3 wt%)
of vinyltrimethoxysilane (VTMS) and 0.33 mol% (1.5 wt%) of butyl
acrylate (BA), which has been obtained in the same way as polymer A,
except that during polymerisation butylacrylate comonomers were added.
Polymer C has a density of 925 kg/m3 and an MFR2 (190 °C, 2.16 kg) of
0.9 g/lOmin.
d) Polymer D is a ethylene copolymer containing 0.26 mol% (1.3 wt%)
of vinyltrimethoxysilane (VTMS) and 0.91 mol% (4.0 wt%) of butyl
acrylate (BA), which has been obtained in the same way as polymer A,
except that during polymerisation butylacrylate comonomers were added.
Polymer D has a density of 925 kg/m3 and an MFR2 (190 °C, 2.16 kg) of
0.8 g/lOmin.
e) Polymer E is a ethylene copolymer containing 0.30 mol% (1.5 wt%)
of vinyltrimethoxysilane (VTMS) and 1.6 mol% (7 wt%) of butyl acrylate
(BA), which has been obtained in the same way as polymer A, except that
during polymerisation butylacrylate comonomers were added. Polymer E
has an MFR2 (190 °C, 2.16 kg) of 1.69 g/10min.
f) Polymer F is a ethylene copolymer containing 0.34 mol% (1.7 wt%)
of vinyltrimethoxysilane (VTMS) and 2.9 mol% (12 wt%) of butyl acrylate
(BA), which has been obtained in the same way as polymer A, except that
during polymerisation butylacrylate comonomers were added. Polymer F
has a density of 925 kg/m3 and an MFR2 (190 °C, 2.16 kg) of 1.50
g/10min.
g) Polymer G is a ethylene copolymer containing 1.8 mol% (8 wt%) of
butyl acrylate (BA), which has been obtained in the same way as polymer
A, except that during polymerisation butylacrylate comonomers were

added, but no silane group containing comonomers. Polymer G has a
density of 923 kg/m3 and an MFR2 (190 °C, 2.16 kg) of 0.50 g/10min.
h) Polymer H is a ethylene copolymer containing 4.3 mol% (17 wt%) of
butyl acrylate (BA), which has been obtained in the same way as polymer
A, except that during polymerisation butylacrylate comonomers were
added, but no silane group containing comonomers. Polymer H has a
density of 925 kg/m3 and an MFR2 (190 °C, 2.16 kg) of 1.20 g/10min.
i) Polymer I is an ethylene copolymer containing 0.43 mol% (1.9 wt%)
vinyltrimethoxysilane (VTMS) and 4.4 mol% (17 wt%) of butylacrylate
(BA), which has been obtained in the same way as polymer A, except that
polymerisation butylacrylate comonomers were added. Polymer I has an
MFR2 (190°C, 2,16 kg) of 4.5 g/10 min and a density of 928 kg/m3.
j) Catalyst masterbatch CM-A consists of 1.7 wt% dodecylbenzene-
sulphonic acid crosslinking catalyst, drying agent and antioxidants
compounded into an ethylene butyl acrylate (BA) copolymer with an BA
content of 17 wt-% and MFR2 = 8 g/10 min.
k). Polyurethane based cast resin PU 300 is a naturally coloured unfilled
two component system intended to be used for 1 kilovolt cable joints (in
accordance with VDE 0291 teil 2 type RLS-W). It has a density of 1225
kg/m3 and a hardness (Shore D) of 55. The cast resin is produced by H6hne
GmbH.
1) Polyurethane based cast resin PU 304 is a blue filled two component
system intended to be used for 1 kilovolt cable joints. It has a density of
1340 kg/m3 and a hardness (Shore D) of 60. The cast resin is produced by
Höhne GmbH.
The amount of butyl acrylate in the polymers was measured by Fourier
Transform Infrared Spektroscopy (FTIR). The weight-%/mol-% of butyl
acrylate was determined from the peak for butyl acrylate at 3450 cm-1,
which was compared to the peak of polyethylene at 2020 cm-1.
The amount of vinyl trimethoxy silane in the polymers was measured by
Fourier Transform Infrared Spektroscopy (FTIR). The weight-% of vinyl

trimethoxy silane was determined from the peak for silane at 945 cm-1,
which was compared to the peak of polyethylene at 2665 cm-1.
2. Production of the low voltage power cables
Cables consisting of an 8 mm2 solid aluminium conductor and an insulation
layer thickness of 0.8 mm (for the samples in table 1) and 0.7 mm (for the
samples in Fig. 1 and Fig. 2) were produced in a Nokia-Maillefer 60 mm
extruder at a line speed of 75 m/min by applying the following conditions:
Die: Pressure (wire guide with a diameter of 3.65 and a pressure die with a
diameter of 5.4 mm for the samples in table 1 and wire guide with a
diameter of 3.0 and a pressure die with a diameter of 4.4 mm for the
samples in Fig. 1 and Fig. 2).
Conductor: Non-preheated, if not anything else mentioned.
Cooling bath temperature: 23°C.
Screws: Elise
Temperature profile: 150, 160, 170, 170, 170, 170, 170, 170°C for the
samples in Table 1, Fig. 1 and Fig. 2.
For the crosslinked samples, the catalyst masterbatch was dry blended into
the polymers prior to extrusion.
3. Test Methods
a) Mechanical and adhesive properties
The mechanical evaluation of the cables was performed according to ISO
527 and the test of adhesion to polyurethane was based on VDE 0472-633.
b) Ageing with PVC
A plaques of the insulation material is placed in an oven at 100°C for 168
hours. PVC plaques are placed on both side of the insulation material
plaque. Dumbells are punched out from the plaques after the testing and

then conditioned in 23°C and 50 % humidity for 24 hours. The tensile tests
are then performed according to ISO 527. The samples that have been aged
together with PVC are also weighten before and after ageing. Samples that
have been aged in an oven at 100°C for 168 hours without contact to PVC
and also other samples that are imaged have been tested according to ISO
527.
4. Results
The results given in Table 1 show that both for crosslinked and for non-
crosslinked (thermoplastic) polymers E, F and G, H, respectively, the
mechanical properties are improved upon incorporation of the polar group
containing butyl acrylate comonomers into the polymers.
Furthermore, in Table 2 it is shown that the adhesion to polyurethane of
polymers C and D is improved even for low amounts of incorporated
butylacrylate so that good adhesion to polyurethane according to VDE
0472-633 is obtained.
Fig. 1 and Fig. 2 show that the mechnical properties of low voltage power
cables according to the invention are improved when the insulation layer is
extruded at the same conductor preheating temperature as the comparative
material. In particular, for the elongation at break, this applies also for the
case where no preheating at all is applied.
Table 3 shows, surprisingly, that polar groups containing insulation
materials have improved resistance to the deterioration of the mechanical
properties caused by the plasticiser in the PVC even then the polar groups
containting insulation material adsorb more plasticiser compared to the
reference.





We claim:
1. A low voltage power cable comprising an insulation layer with a density below
1100 kg/m3 which comprises a polyolefin having incorporated 0.02 to 4 mol% of a
compound having polar groups, and having incorporated a compound having
hydrolysable silane groups and which comprises 0.0001 to 3 wt.% of a silanol
condensation catalyst.
2. A low voltage power cable as claimed in claim 1. wherein the polar groups are
selected from siloxane, amide, anhydride, carboxylic, carbonyl, hydroxyl, ester and
epoxy groups.
3. A low voltage power cable as claimed in claim 2, wherein the compound having
polar groups is butyl aerylate.
4. A low voltage power cable as claimed in any of the preceeding claims, wherein
the polyolefin comprises 0.1 to 2.0 mol% of the compound having polar groups.
5. A low voltage power cable as claimed in claim 1, wherein the polyolefin
comprises 0.001 to 15 wt.% of the compound having silane groups.
6. A low voltage power cable as claimed in claim 1 or 5, wherein the polymer
composition comprises a sulphonic acid or an organic tin compound as a silanol
condensation catalyst.
7. A low voltage power cable as claimed in any of the preceeding claims, wherein
the thickness of the insulation layer is 0.4 to 3 mm.
8. A process for producing a low voltage power cable comprising producing an
insulation layer comprising a polyolefin having incorporated 0.02 to 4 mol% of a
compound having polar groups and having incorporated a compound having
hydrolysable silane groups and which comprises 0.0001 to 3 wt.% of a silanol
condensation catalyst: extruding the insulation layer on a conductor which is preheated
to a maximum temperature of 65° C.
9. A process as claimed in claim 8, wherein the extrusion of the insulation layer is
performed on the non-preheated conductor.

Documents:

00893-kolnp-2006 assignment.pdf

00893-kolnp-2006 correspondence-1.1.pdf

00893-kolnp-2006 form-18.pdf

00893-kolnp-2006-abstract.pdf

00893-kolnp-2006-claims.pdf

00893-kolnp-2006-correspondence other.pdf

00893-kolnp-2006-description complete.pdf

00893-kolnp-2006-drawings.pdf

00893-kolnp-2006-form 3.pdf

00893-kolnp-2006-from 1.pdf

00893-kolnp-2006-from 5.pdf

00893-kolnp-2006-international publication.pdf

00893-kolnp-2006-international search report.pdf

00893-kolnp-2006-other document.pdf

00893-kolnp-2006-pct form.pdf

00893-kolnp-2006-priority document.pdf

893-KOLNP-2006-ABSTRACT.pdf

893-KOLNP-2006-AMENDED CLAIMS.pdf

893-kolnp-2006-assignment.pdf

893-KOLNP-2006-CANCELLED PAGES.pdf

893-KOLNP-2006-CORRESPONDENCE 1.1.pdf

893-KOLNP-2006-CORRESPONDENCE 1.2.pdf

893-kolnp-2006-correspondence.pdf

893-KOLNP-2006-DRAWINGS.pdf

893-kolnp-2006-examination report.pdf

893-KOLNP-2006-FORM 1.pdf

893-kolnp-2006-form 18.pdf

893-KOLNP-2006-FORM 2.pdf

893-kolnp-2006-form 3-1.1.pdf

893-KOLNP-2006-FORM 3.pdf

893-kolnp-2006-form 5.pdf

893-KOLNP-2006-FORM-27.pdf

893-kolnp-2006-granted-abstract.pdf

893-kolnp-2006-granted-claims.pdf

893-kolnp-2006-granted-description (complete).pdf

893-kolnp-2006-granted-drawings.pdf

893-kolnp-2006-granted-form 1.pdf

893-kolnp-2006-granted-form 2.pdf

893-kolnp-2006-granted-specification.pdf

893-kolnp-2006-others-1.1.pdf

893-KOLNP-2006-OTHERS.pdf

893-KOLNP-2006-PETITION UNDER RULE 137.pdf

893-kolnp-2006-reply to examination report-1.1.pdf

893-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

abstract-00893-kolnp-2006.jpg


Patent Number 247411
Indian Patent Application Number 893/KOLNP/2006
PG Journal Number 14/2011
Publication Date 08-Apr-2011
Grant Date 05-Apr-2011
Date of Filing 10-Apr-2006
Name of Patentee BOREALIS TECHNOLOGY OY
Applicant Address P.O. BOX 330, FIN-06101, PORVOO
Inventors:
# Inventor's Name Inventor's Address
1 JUNGKVIST, JONAS SLOTTSKOSGATAN 75, S-414 70 GOTEBORG
2 DETLEF, WALD JAN VAN GENTSTRAAT 29, B-2000 ANTWERPEN
3 SULTAN, BERNT-AKE SOBACKEVAGEN 16, S-444 42 STENUNGSUND
PCT International Classification Number H01B 3/44
PCT International Application Number PCT/EP2004/011979
PCT International Filing date 2004-10-22
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 03024371.1 2003-10-24 EUROPEAN UNION