KR20170118025A - Organogel for electrical cable insulating layer - Google Patents

Abstract

The present invention relates to an electrical cable comprising at least one conductor (10) and an electrically insulating layer (12) impregnated with an insulating solvent, wherein the insulating layer (12) surrounds the conductor (10) And an organic gel containing an organic-gelling agent, wherein the oil is a non-polar oil having a flash point of 200 ° C or less.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic gel for an electric cable insulation layer,

The present invention relates to an electric cable comprising an electrically insulating layer impregnated with an insulating solvent comprising an organic gel.

More specifically, the electric cable is a DC transmission cable (DC transmission cable), more preferably a high voltage DC cable (HVDC transmission cable) having a transmission capacity of more than 1200 MW.

A typical DC transmission cable includes an insulation system and a conductor comprising a plurality of layers such as an inner semiconductive shield, an insulator and an outer semiconductive shield. Cables are also provided with casings, reinforcements, etc., to withstand water penetration and any mechanical wear or force during manufacture, installation and use. Most of the DC cable systems provided to date are for subsea traverses or related ground cables.

Insulators are typically rolls comprising almost all paper tapes, i.e. tapes based on paper or cellulosic fibers, but the application of laminated tape materials, i.e. tapes of two or more layers bonded together, such as laminated polypropylene paper tapes, . The winding body is typically impregnated with electrically insulating oil or mass.

WO 99/33068 discloses a DC cable having an electrically insulating layer impregnated with an insulating solvent and at least one conductor. The insulating solvent comprises an oil and a gelling additive, wherein the gelling additive determines the viscosity and elasticity of the insulating solvent.

Thus, the cable has a sufficiently low viscosity at its (higher) impregnation temperature in order to stabilize the flow properties and flow behavior of the solvent in its impregnated insulation layer, (I.e., oil and gelling additive) having a sufficiently high viscosity and elasticity at a (lower) operating temperature of from about 10 to about 30 DEG C and having a sufficiently rapid viscosity increase from the impregnation to the operating temperature to enable higher operating temperatures, Lt; / RTI >

According to WO 99/33068, the gelling additive molecules can be selected from a wide variety of compounds characterized by polar moieties capable of forming hydrogen bonds, wherein the gelling additive, along with the oil, To form a polymer gel, or to form an organic gel when the gelling additive is a compound that is not a polymer. In the three examples of the publication, three gelling additives are used in combination with unspecified naphthenic mineral oil, respectively.

However, the combination of any unspecified naphthenic mineral oil with any gelling additive compound as defined in WO 99/33068 does not provide an insulating solvent with sufficiently stable insulating properties in the electrically insulating layer. Typically, the gelling additives and oils described in the publications are used because the gelling additive does not dissolve in the oil, resulting in a suspension of the additive in the oil, or because the gelling additive and the oil form a gel-phase and phase-separated mixture in the oil phase Referred to also as "bleeding") to form a phase separated mixture.

The present invention addresses the above-mentioned problems of the prior art and proposes to optimize the insulation stability as well as the non-bleeding properties (i.e., stability) of the insulation solvent used to impregnate the electrical insulation layer of the electrical cable.

It is an object of the present invention to provide an electrical cable comprising at least one conductor and an electrically insulating layer impregnated with an insulating solvent, wherein the insulating layer surrounds the conductor and the insulating solvent comprises an organic- And the oil is a non-polar oil having a flash point of 200 ° C or less.

The non-polarity of the oil is essential to have sufficient insulating properties of the impregnated electrical insulation layer.

In a first variant according to the non-polar nature of the oil, the non-polar oil has a low content (C _A ) of aromatic compounds according to the ASTM D 2140 standard, so the wt% of C _A is preferably less than 12% Is less than 10%, and even more preferably the C _A is less than 6%.

In a second variant, according to the non-polar nature of the oil and according to the IP 346 test, the nonpolar oil has a low weight percentage which can be extracted therefrom using DMSO (polar solvent) after diluted with cyclohexane. Preferably, the DMSO-extractable weight percent is less than 3%, preferably less than 2%, more preferably less than 1.5%.

In a third variation according to the non-polar nature of the oil, the non-polar oil has a low content of aromatics (C _A ) according to ASTM D 2140 standard (first variant) and a ratio of DMSO-extractability (%) Is low (second modified example).

Advantageously, the combination of the specific oils and organo-gelling agent of the present invention provides a clear homogeneous organic gel that does not exhibit bleeding phenomenon, with optimized stable insulating properties (e.g., very high breakdown voltage) without any precipitate .

According to the present invention, the flash point of the oil indicates the degree of volatilization of the oil. Flashpoints are typically measured by Pensky Marten (PM) Closed Cup Method ASTM D 93 A or similar tests, such as ASTM D92 or ASTM D93 tests. The flash point is reached when the oil exits enough gas to ignite the gas mixture on the oil in the presence of an open flame. The flash point of the oil is preferably 180 DEG C or lower, more preferably 160 DEG C or lower. The flash point of the oil is preferably 95 占 폚 or higher, more preferably 110 占 폚 or higher, even more preferably 120 占 폚 or higher.

It is preferred that the non-polar oil be selected from hydrocarbon oils, silicone oils, fluoro-oils and natural oils (e.g. vegetable oils, terpene-derived oils), or mixtures thereof, more preferably hydrocarbon oils. In the hydrocarbon oil, naphthenic, paraffin or isoparaffin oil, or mixtures thereof, may be selected, wherein they may be mineral oils, semi-synthetic mineral oils (such as hydrotreated mineral oil) or synthetic oils (such as hydrogenated poly- have. Semi-synthetic hydrogenated mineral oil (naphthene, paraffin or isoparaffin) is more preferred.

The nonpolar oils of the present invention may be supplied by any source or distributor, such as Nynas, Shell, Renkert Oil, Neste Oil, and the like.

In certain embodiments, the oil viscosity is less than 40 cSt (centistokes) at 40 캜, preferably less than 20 cSt at 40 캜, more preferably less than 10 cSt at 40 캜. The oil viscosity is determined by measuring the dynamic viscosity (cSt) by a Ubbelhode capillary according to ASTM D445.

The nonpolar oil used in the present invention preferably comprises branched and / or cyclic molecules. For example, heptamethyl nonane is preferable to n-hexadecane, and decalin is preferable to n-dodecane. Other examples are alkylcyclohexanes (branched) or alkyl decalines (i.e., they are hydrogenated alkylbenzenes and hydrogenated alkylnaphthalenes). Branching generally means that the various isomers are present in the oil, which is preferred because it is preferred that the oil consists of a mixture of molecules. As a result, an oil consisting mainly of a mixture having a linear structure (i.e., paraffin oil) is also possible.

Organic-gelling agent

Organo-gelling agents are molecules that self-assemble in solution by supramolecular interactions, typically hydrogen bonding interactions and / or pi-pi interactions. In solution, the organization of the organo-gelling agent molecules occurs mainly in one direction, forming a long supramolecular structure. The interaction between these structures is becoming important as a sufficiently high concentration of organo-gelling agent molecules, which causes gelation of the solution. However, supramolecular structures are not polymers, or in other words, organo-gelling agents are not macromolecules or polymers composed of repeating structural units (monomers) typically linked by covalent chemical bonds. Indeed, by heating the solution, the supramolecular structure is reversibly decomposed, resulting in a solution of individual molecules or very small aggregates of some molecules, which leads to rapid viscosity reduction and facilitates processing at higher temperatures.

By way of example, the molecular weight of the organo-gelling agent is less than 5,000 daltons, more preferably less than 2,000 daltons, even more preferably less than 1,000 daltons; More specifically, the molecular weight of the organic-gelling agent is from 200 to 800 daltons.

In a preferred embodiment, the organo-gellant comprises a mixture of organo-gellant compounds, more preferably a mixture of similar organo-gellant compounds. Thus, in the above case, the organo-gelling agent can not consist of a single organo-gelling agent compound.

The term "mixture" encompasses molecules comprising two or more different molecules, preferably 2 to 1,000 different molecules, preferably 2 to 250, more preferably 4 to 100, most preferably 6 to 60 molecules Organic-gelling agent composition. In this composition, the ratio in which the molecules are present can always be varied. The most abundant species may preferably be present in an amount of 1 mol% to 99 mol%, more preferably 3 mol% to 60 mol%, and most preferably 5 mol% to 40%. The least abundant species is preferably present in an amount of from 0.01 mol% to 49 mol%, preferably from 0.05 mol% to 25 mol%, and most preferably from 0.1 mol% to 15 mol%.

Examples of mixtures of organic-gellant compounds are mixtures of enantiomers (i.e., racemates), mixtures of stereoisomers (e. G., Mixtures of enantiomers and diastereomers), or mixtures of isomers.

The term "mixture of like compounds" is understood to be a mixture of compounds of the same chemical group or type. More specifically, the hydrogen bonding motif in the molecule of the mixture is the same, wherein the hydrogen bonding motif is defined as a hydrogen bonding functional group (e.g., urea or amide) and a spacer between these functional groups. This is further highlighted, described and illustrated below.

In certain embodiments according to the present invention, the organo-gelling agent is selected from a urea based compound, a mixture of urea based compounds, a mixture of amide based compounds and amide based compounds, or mixtures thereof.

The organo-gelling agent is particularly suitable for the production of stable organic gels, which are important for electrical cable insulation applications. The organic-gelling agent in combination with the oil according to the present invention can produce a clear, homogeneous and stable organic gel.

Indeed, to date, most molecules are not organic-gelling agents, nor are molecules with polar segments capable of forming hydrogen bonds with non-polar segments. It is also difficult to predict whether the molecular structure can gel the oil. In addition, some organic-gelling agents may produce organic gels, but these organic gels may not be stable over time (precipitation or bleeding may occur).

In a preferred embodiment, the organo-gelling agent is selected from a mixture of urea based compounds or urea based compounds, and mixtures of amide based compounds or amide based compounds.

It is preferred that the mixture according to the invention consists of similar types of molecules of organo-gelling agent, which means that if the hydrogen bonding motif is defined as a hydrogen bonding functional group (preferably urea or amide) and as a spacer between these functional groups, Means that the hydrogen bonding motive in the molecule is the same.

More specifically, the monoureas can be mixed with other monoureas, and the aromatic triamides can be mixed with other aromatic triamides and the like. More specifically, in the case of a mixture comprising a multifunctional amide structure (or in the case of a mixture comprising a multifunctional urea structure), the spacer between the amide- or urea hydrogen bonding functional groups is preferred for all of the mixed organo-gelling agent molecules The same is preferable.

For example,

-Trialkylbenzene-1,3,5-tricarboxamide with other trialkylbenzene-1,3,5-tricarboxamide; or

- 2,4-bis-urea toluene with other 2,4-bis-urea toluene; or

- meta-bis-urea benzene with other meta-bis-urea benzene; or

Mixing a diamide having n carbon atom spacers between two -NHCOR amides with another diamide having n carbon atom spacers between two NHCOR amides; or

- 1,2-bis-urea (S, S) -cyclohexane is mixed with another 1,2-bis-urea (S, S) -cyclohexane.

Also, if amides are to be considered, it is preferred that the orientation of the amide functionality to the spacer be the same for the molecules of the mixture (i. E., Organo-gelling agent molecules). For example, all of the diamides of the mixture may be R1-CONH- (spacer) -NHCO-R2, or all diamides in the mixture may be R1-NHCO- (spacer) -NHCO-R2, Meid is R1-NHCO- (spacer) -CONH-R2, wherein R1 and R2 are mentioned for the understanding of amide functional group orientation, which may be an alkyl radical or other type of group.

The mixture of organo-gellants can be produced by physically mixing a series of individually synthesized organo-gellants. For example, one or more particular 2,4-bis- (dialkylureido) toluene (s) may be combined with one or more other 2,4-bis- (dialkylureido) toluene Mix physically with the ratio.

Alternatively, the mixture can also be synthesized by taking one specific polyfunctional reactant and reacting such building block with a mixture of monofunctional reactants. For example, 2,4-toluene diisocyanate (a specific polyfunctional reactant) reacts with a mixture of primary amine reactants (monofunctional reactants) to produce a mixture of 2,4-bis- (dialkylureido) toluene do or; Or in another example, (S, S) -1,2-diaminocyclohexane is reacted with a mixture of monoisocyanates to produce a mixture of (S, S) -1,2-bis-urea cyclohexane. The nature of the monofunctional reactants (e.g., linear alkyl, branched, cyclic, alkylaryl, etc.) and the proportion of these reactants present in the reactant mixture are freely chosen. Particular and suitable mixtures of monofunctional reactants are racemates, for example racemates of primary amines, racemates of carboxylic acids or derivatives thereof, or racemates of isocyanates.

Due to the mixture according to the invention, it is surprisingly possible to produce organo-gelling agents by mixing molecules that can not gellify or thicken the oil separately. In addition, the mixture makes it possible to optimize the properties of the organic gel (for example, regarding viscosity, gel point, stability, etc.) by altering the specific composition of the mixture.

Urea compound

When referring to urea compounds, these urea functional groups can be general urea (-NH-CO-NH-) or thio-urea (-NH-CS-NH-). Typical urea is preferred.

When referring to urea based compounds, all of the nitrogen atoms in one urea moiety may be replaced by hydrogen, or one of these nitrogen atoms may be alkylated or arylated. Preferably, all of the nitrogen atoms in the urea moiety are substituted with hydrogen to produce the -NH-CO-NH-urea moiety (or -NH-CS-NH-thio-urea moiety) do.

According to the urea-based compounds, this may be selected from mixtures of monourea or monourea, mixtures of bis-urea or bis-urea, and mixtures of tris-urea or tris-urea, more preferably monourea or monourea , And mixtures of bis-urea or bis-urea. A mixture of bis-urea or bis-urea is most preferred.

When the urea compound is substituted with two or more different R-groups, the compound is referred to as an "asymmetric" urea compound. When all of the urea functional groups are replaced by the same R-group, the compounds are referred to as "symmetric" urea-based compounds. The R- group is not a spacer group connecting different urea-functional groups.

When a mixture of urea based compounds is considered, the mixture may comprise:

i. A different symmetrical urea-based compound, or

ii. Different asymmetric urea-based compounds, or

iii. At least one symmetrical urea compound and at least one asymmetric urea compound.

The urea formula as described below relates to a common urea. However, thio-urea (not shown) can likewise be considered in place of general urea.

The monourea (or mixture of mono-urea) or bis-urea (or mixture of bis-urea) may be according to the following formulas Ia and Ib, respectively:

Ia

(Ib)

In the above formulas,

R1 and R2 are different or may be the same, and independently represent hydrogen, linear, specifically, saturated than branched or cyclic, saturated or unsaturated C ₁ -C ₂₄ alkyl, alkylaryl or arylalkyl carbon-based radicals, alkyl-based Radical where the radical may optionally contain from 1 to 3 heteroatoms selected from O, S, F and N and may for example be selected from the group consisting of ethers, thio-ethers, alcohols, amides, carboxylic acids, esters , Urethane, tertiary amine and CF _x (x = 1, 2 or 3) groups,

A is a non-aromatic or aromatic spacer, preferably linear alkylene, branched alkylene, cyclohexylene (preferably R, R- or S, S-1,2-cyclohexylene), 4,4 (4-methylene-bis-phenylene, 4,4'-oxy-bis-phenylene, benzene, naphthalene, phenylene, tris , Isoprenylene, para-mentylene and lysine-derived spacers. Spacer A can also represent a direct covalent bond between two nitrogen atoms.

More preferably, R1 and / or R2 is 2-ethyl-hexyl; 1,5-dimethyl-hexyl; 3,7-dimethyl-octyl; 1-methyl-hexyl; Other branched C ₃ -C ₈ alkyl, linear C ₄ -C ₁₈ alkyl, benzyl, cyclohexyl, alkoxyalkyl and hydroxy-alkyl. More preferably, R1 and / or R2 is 2-ethyl-hexyl; 1,5-dimethyl-hexyl; 1-methyl-hexyl; Branched C ₃ -C ₆ alkyl; And linear C ₄ -C ₁₀ , C _16, and C ₁₈ alkyl. A 2-ethylhexyl radical is most preferred.

In certain embodiments, when the R 1 and / or R 2 groups have a stereogenic center, these groups are preferably racemic groups (or more precisely, these R 1 and / or R 2 groups are racemates, Primary amine or racemic isocyanate).

When R < 1 > is different from R < 2 >, an asymmetric urea compound is obtained.

In formula (Ia), when R1 is different from R2 so as to have an asymmetric mono-urea compound, R1 (or R2) is selected from the group consisting of C R < 1 > is preferably selected from aryl or benzyl derived from a _{6 to 15} carbon radical, and R2 (or R1) is hydrogen, linear, optionally including 1 to 3 heteroatoms selected from O, S, F and N , Branched or cyclic, saturated or unsaturated C ₁ -C ₂₄ alkyl radicals.

In formula (Ib), when R1 is different from R2 to have an asymmetric bis-urea compound, R1 (or R2) optionally contains 1 to 3 heteroatoms selected from O, S, F and N, And R < 2 > are preferably selected from a saturated or unsaturated, non-cyclic, branched C ₃ -C ₁₅ carbon radical, and R 2 (or R 1) is optionally substituted with 1 to 3 heteroatoms selected from O, S, F and N Linear, branched, or cyclic, saturated or unsaturated C ₁ -C ₂₄ alkyl radical, including, but not limited to,

When a mixture of mono-urea according to formula (Ia) is considered, all of the molecules in said mixture preferably have the same R1-group, and preferably have a specific aryl-derived group or a specific benzyl-derived group. For example, a mixture consisting of only 1-benzyl-monourea can be considered.

If a mixture of bis-urea according to formula (Ib) is considered, all molecules in said mixture are preferably similar and have the same spacer A. For example, the spacer A in all molecules of the mixture of formula (Ib) may be R, R-1,2-cyclohexylene spacer or may be a hexylene spacer.

In a preferred embodiment wherein spacer A of formula (Ib) is an aromatic spacer, the urea compound may be an aromatic bis-urea (or mixture of aromatic bis-ureas) according to the formula

(II)

In the above formulas, R 1 and R 2 are as defined above, and R 3 is a hydrogen atom or a linear or branched C ₁ -C ₄ alkyl radical.

When a mixture of bis-urea according to formula (II) is taken into consideration, in said mixture, it is preferred that the urea group in all molecules is connected to the same aromatic spacer. For example, meta-bis-urea is mixed with other meta-bis-urea, para-bis-urea is mixed with other para-bis-urea and ortho- do.

Preferably, the aromatic bis-urea can be a bis-urea substituted toluene (or a mixture of bis-urea substituted toluene) according to the following formula:

(III)

In the above formulas, R 1 and R 2 are as defined above.

When considering a mixture between formulas (II) and (III), the urea group in formula (II) is also preferably meta-substituted in the ring.

Amide compound

When referring to amide-based compounds, these amide functionalities can be the general amide (-NH-CO-) or thio-amide (-NH-CS-). Typical amides are preferred.

When referring to an amide-based compound, the nitrogen atom in the amide moiety is substituted with hydrogen to produce an -NH-CO-amide moiety (or -NH-CS-thio-amide moiety) that can participate in hydrogen bond interactions .

According to the amide-based compounds, they may be selected from mixtures of diamides or diamides, mixtures of triamides or triamides, and mixtures of tetramides or tetramides.

When the amide-based compound is substituted with two or more different R-groups, the compound is referred to as an "asymmetric" amide-based compound. When all amide functionalities are replaced by the same R-group, the compound is referred to as a "symmetrical" amide-based compound. The R- group is not a spacer group connecting the different amide functionalities.

When considering a mixture of amide-based compounds, the mixture may comprise:

i. Different symmetrical amide-based compounds, or

ii. Different asymmetric amide-based compounds, or

iii. At least one symmetrical amide compound and at least one asymmetric amide compound.

The amide formulas as described below relate to common amides. However, thioamides (not shown) can likewise be considered in place of the usual amides.

Diamide

In a first example, the diamide (or mixture of diamides) may be represented by the formula (IV) or (V)

Formula IV

Formula V

In the above formula, R4 and / or R5, and R7 and / or R8 are different or may be the same, and a hydrogen atom, a linear, branched or cyclic, saturated or unsaturated C ₁ -C ₃₆ alkyl, aryl or arylalkyl May be independently selected from saturated radicals, optionally containing one to three heteroatoms selected from carbon-based radicals, more particularly O, S, F and N, such as ether, thio-ether, A carboxylic acid, an ester, a urethane, a tertiary amine and a CF _x (x = 1, 2 or 3) group.

In the case of groups R4 and / or R5 they are preferably hydrogen, 2-ethyl-hexyl; 1,5-dimethyl-hexyl; 3,7-dimethyl-octyl; 1-methyl-hexyl; Are independently selected from other branched C ₃ -C ₈ alkyl, linear C ₄ -C ₁₈ alkyl, benzyl, cyclohexyl, alkoxyalkyl (eg, 3-methoxy-propyl) and hydroxy-alkyl.

In the case of groups R7 and / or R8, they are preferably 1-ethyl-pentyl; 1-methyl-ethyl; 1-methyl-propyl; tert-butyl; 1-ethyl-propyl; 2,6-dimethyl-heptyl; Other branched C ₃ -C ₈ alkyl; C ₉ -C ₃₆ 1- alkyl- are independently selected from alkyl-alkyl, linear C ₄ -C ₁₈ alkyl, benzyl, cyclohexyl and alkoxy.

In certain embodiments, when the R4 and / or R5 group, or the R7 and / or R8 group comprises stereocenters, these groups are preferably racemic groups. Or, more precisely, from a racemate, such as a racemic primary amine reactant (for the formula IV) or a racemic carboxylic acid derived reactant (for the formula V).

When R4 is different from R5 or when R7 is different from R8, an asymmetric di-amide compound is obtained.

Part B is a non-aromatic or aromatic spacer and is preferably selected from linear alkylene, branched alkylene, cyclohexylene, camphorylene, phenylene, bis-phenylene, naphthalene, and spacers derived from glutamic acid or aspartic acid do. Spacer B may also represent a direct covalent bond between the two carbons.

Part C is a non-aromatic or aromatic spacer, preferably linear alkylene, branched alkylene, cyclohexylene (preferably R, R- or S, S-1,2-cyclohexylene) (4-methylene-bis-phenylene, 4,4'-oxy-bis-phenylene, benzylene, naphthalene, tris ≪ / RTI > is selected from the group consisting of boron, boron, boron, boron, boron, poronylene, para-mentylene and lysine-derived spacers. Spacer C may also represent a direct covalent bond between two nitrogen atoms.

All of the molecules in the mixture are preferably similar, and the same spacer B (in the case of a mixture of the formula IV) or the same spacer C (in the case of a mixture of the formulas V and V), in consideration of the mixture of the diamides of the formula IV or the diamides of the formula V, In the case of a mixture of < / RTI > For example, the spacer C in all molecules of the mixture of formula (V) can be a (R, R) -1,2-cyclohexylene spacer or a hexylene spacer.

In a second example, the di-amide (or a mixture of diamides) is a cyclic diamide and can be according to the following formula VI:

VI

In the above formulas,

R10 and R11 may be the same or different and are selected from the group consisting of hydrogen, linear, branched or cyclic, saturated or unsaturated C ₁ -C ₂₄ alkyl, alkylaryl or arylalkyl carbon radicals, more particularly O, S, F And N, and may be independently selected from saturated alkyl radicals, including, for example, ethers, thio-ethers, alcohols, amides, carboxylic acids, esters, urethanes, tertiary amines and CF _x (x = 1, 2 or 3) groups.

More preferably, R10 and R11 are derived from amino acid residues and are, for example, alkyl residues comprising hydrogen, benzyl, alkyl, branched alkyl, or alkyl-ester or alcohol groups.

In certain embodiments, when the R10 and / or R11 group comprises a stereogenic center, those groups are preferably racemic.

When R < 10 > is different from R < 11 >, an asymmetric di-amide compound is obtained.

When considering a mixture of molecules of formula VI, it is preferred that all molecules in these mixtures have the same structure for the six-membered ring, i.e. all molecules have the same R, R- or the same S, S- , S-structure.

Triamide

According to the triamide, the amide compound can be an aromatic triamide.

In a first example, the aromatic triamide (or a mixture of aromatic triamides) is benzene-1,3,5-tricarboxamide (BTA) (or a mixture of BTA's)

Formula VII

In a second example, the aromatic triamide (or mixture of aromatic triamides) may be subjected to the following formula VIII:

VIII

Linear, branched or cyclic, saturated or unsaturated C ₁ -C ₃₆ alkyl, which may be the same or different and is hydrogen, linear, branched or cyclic, saturated or unsaturated, in the formulas VII or VIII, R 4, R 5 and / or R 6 and R 7, R 8 and / Alkyl, alkylaryl or arylalkyl carbon radicals, more particularly from 1 to 3 heteroatoms selected from O, S, F and N, such as, for example, ethers, Thio-ether, alcohol, carboxylic acid, ester, urethane, tertiary amine and CF _x (x = 1, 2 or 3) groups.

In the case of the groups R4, R5 and / or R6 of formula VII, they are preferably 2-ethyl-hexyl; 1,5-dimethyl-hexyl; 3,7-dimethyl-octyl; 1-methyl-hexyl; Are independently selected from other branched C ₃ -C ₈ alkyl, linear C ₄ -C ₁₈ alkyl, benzyl, cyclohexyl, alkoxyalkyl (eg, 3-methoxy-propyl) and hydroxy-alkyl.

For the groups R7, R8 and / or R9 of formula (VIII), they are preferably 1-ethyl-pentyl; 1-methyl-ethyl; 1-methyl-propyl; tert-butyl; 1-ethyl-propyl; 2,6-dimethyl-heptyl; Other branched C ₃ -C ₈ alkyl; C ₉ -C ₃₆ 1- alkyl- are independently selected from alkyl-alkyl, linear C ₄ -C ₁₈ alkyl, benzyl, cyclohexyl and alkoxy.

In certain embodiments, when the R4, R5 and / or R6 groups of formula VII, or the R7, R8 and / or R9 groups of formula VIII comprise stereocenters, these groups are preferably racemic groups. Or, more precisely, from the racemic reactant.

When at least one of the R groups selected from R4, R5 and R6 is different from one of the remaining two, an asymmetric triamide compound is obtained.

When at least one of the R groups selected from R7, R8 and R9 is different from one of the remaining two, an asymmetric triamide compound is obtained.

In a third example, the triamide (or a mixture of triamides) may be represented by the following formula IX:

IX

In the above formulas, R4, R5 and R6 are as defined above for formula VII.

In certain embodiments, when the R4, R5 and / or R6 group of formula IX comprises stereocenters, these groups are preferably racemic groups. Or, more precisely, from the racemic reactant.

When at least one of the R groups selected from R4, R5 and R6 is different from one of the remaining two, an asymmetric triamide compound is obtained.

Considering a mixture of molecules of formula IX, all molecules in this mixture are preferably similar and have the same structure for the 1,3,5-cyclohexylene ring, And have the same axial and / or horizontal substitution pattern on the cyclohexylene ring.

Tetramide

The tetramide may be a pyromellitic amide compound or a mixture thereof, for example, benzene-1,2,4,5-tetracarboxamide.

Among the above-mentioned formula (Ia), formula (Ib), formula (II), formula (III), formula (IV), formula V, formula VI, formula VII, formula VIII and formula IX, preference is given to formula Ia, formula Ib, formula III, formula V and formula VII . (III) and (VII) are most preferred. In the present specification, in the general formulas (I) to (IX), the hydrogen bonding motive attracts the bonded R-radical, that is, the R-radical is not part of the hydrogen bonding motif.

In addition, organic-gelling agents which are mixtures of similar compounds, as opposed to organic-gelling agents consisting of a single compound, are preferred. Mixtures of similar structures according to formula (Ia) or (Ib) or (III) or (II) and (III) or (V) or (VII) are preferred. Mixtures of similar structures according to formula (III), (II) and (III) or according to formula (VII) are most preferred.

From the above it can be seen that the present invention provides a type of organo-gelling agent that can be used to effectively and stably thicken or gel the oil applied to electrical cable insulation.

Other types of organic-gelling agents

The concept of generating an organo-gelling agent from a mixture of like molecules can be applied to other types of molecular structures having (multiple) side-chain alkyl groups, such as metal salts (such as mono- or di- (For example, cholesterol derivatives), amino acid derivatives or oligopeptides, melitic acid derivatives (for example, divalent or trivalent metal salts of carboxylic acids, fatty acids or phosphoric acids) (For example, amide amide), a system which aggregates due to the π-π-interaction (eg, porphyrin, phthalocyanine, phenylene vinylidene, fluorene, azo-phenylene, another dye, anthraquinone) Acid-based, pyrimidine-barbituric or melamine or triazine-based, cyclodextrin based, donor-accepting systems), polyvalent Benzyl-3,4-dihydroxypyrrolidine), a bola-amphiphilic structure, a molecule having a mesogenic group (for example, a trialkylgalic acid derivative, a 4-alkoxybenzoic acid derivative) .

Organic gel

The insulating solvent of the present invention includes the organic-gelling agent and the oil specifically all described above.

Contrary to viscous solutions, the fluid in the vial is regarded as a gel when fluid flow is not generated in seconds or minutes when the vial is inverted, whereas a highly viscous solution flows slowly within a few seconds, The solution flows quickly immediately.

It is preferred that the insulating solvent or more specifically the organic gel of the present invention is clear (or transparent) as opposed to being cloudy or white. Also, macroscopically homogeneous is preferred, as opposed to mixtures (suspension) with precipitates, or mixtures which exhibit any other type of phase separation, such as gels and mixtures of phase separated liquids.

Organic gels are viscous solutions, meaning they have both elastic (i.e., solid-like) and viscous (i.e., liquid-like) properties. The gelation point (T _gel ) of the organic gel is a lower temperature than that of the organic gel having more elastic or solid-like properties and is a higher temperature than that of the organic gel having more of a liquid-like aspect.

The gelation point of the organic gel can be measured by rheological measurement, or more specifically by complex viscosity measurement or viscoelastic measurement. Rheological measurements are typically carried out using a dynamic flow meter in a vibrating manner such as a Brookfield flow meter. The gel point of the present invention is measured under dynamic vibration of 0.095 Hz.

For example, the organic gel was placed in a concentric cylindrical cup with a conical interior and heated from 4 ° C to 110 ° C under 1% strain under a dynamic vibration of 0.095 Hz at 0.5 ° C / min. As a function of temperature, rheological parameters such as storage modulus (G ', unit Pa, reflecting the solid-like properties of the gel), loss modulus (G ", unit Pa, reflecting the liquid- complex viscosity can be recorded η ^* (㎩.s). then, the gelation point is defined as the temperature for the same time and the storage modulus G 'is the loss modulus G ".

It is preferred that the impregnation temperature of the cable is higher than the gelation point of the applied organic gel in the insulating layer, while the operating temperature of the cable is preferably not lower or significantly higher than the gelation point.

In particular, the gelation point of the organic gel can be selected from 45 ° C to 90 ° C. This particular gel point range provides an organic gel that imparts all of the beneficial properties to the impregnated electrical insulation layer of the present invention.

It is preferred that a gelling point higher than 90 deg. C is not required, since it means that a too high impregnation temperature should be used.

Gelation points below 45 ° C present a risk of cavitation in the electrical insulation layer due to polarity reversal of the cable at the operating temperature. The polarity reversal causes a temperature change in the cable, which can alter the structure of the insulating solvent and lead to cavitation (i.e., the formation of small gas bubbles). The cavity can seriously increase the possibility of breakage (breakdown) of the cable.

Typically, the rheological aspect of the insulating solvent of the present invention may be characterized by a "solid" (elastic) pattern of 0 ° C to about 60 ° C, and a larger viscous pattern of 60 ° C to 100 ° C. The composite viscosity at 0 占 폚 may be about 100 to 5,000 Pa.s. The viscosity at the gelation point may be about 50 to 2,000 Pa.s and the viscosity at 110 deg. C may be about 0.01 to 10 Pa s.

A known method of characterizing the organic gel complex viscosity (Pa) is to use a dynamic flow meter in a vibrating manner, for example, using a Brookfield flow meter as mentioned and described above.

Thus, the insulating solvent of the present invention exhibits a sharp complex viscosity drop in a part of the temperature window between 45 ° C and 110 ° C. The composite viscosity drop is preferably greater than 20 (e.g., 200 Pa.s to 2 Pa.s) within 40 < 0 > C, more preferably greater than 30 within 35 & More preferable. The composite viscosity drop is preferably greater than 100 Pa s, more preferably greater than 250 Pa s, and most preferably greater than 500 Pa s.

In particular, the organic gel may comprise up to 20% by weight organic-gelling agent, more preferably up to 10% by weight organic-gelling agent. The insulating solvent may comprise at least 2% by weight of organic-gelling agent. Preferably, the organic gel may comprise from 3% to 7% by weight organic-gelling agent. The organic gel preferably comprises only the oil and organic-gelling agent according to the invention.

However, the insulating solvent comprising the organic gel may further comprise additional components such as rheology modifiers, antioxidants, metal deactivators or hydrogen scavengers. It is preferred that the insulating solvent comprises more than 97% by weight organic gel.

An example of a rheology modifier is an elastomer that further enhances the elasticity of the gel, wherein the elastomer is 2 wt% or less in the insulating solvent. The addition of more than 2% by weight of the elastomer may cause rheological problems due to the miscibility between the elastomer and the organo-gelling agent, as well as the risk of bleeding. For example, the elastomer may be selected from polyisobutene (PIB), more preferably low molecular weight polyisobutene (LMWPIB), such as those having a molecular weight lower than 10,000 g / mol, more preferably lower than 2,000 g / mol .

Examples of antioxidants include phenol-derived antioxidants such as 2,6-di-tert-butyl-4-methylphenol (BHT) or the Irganox type of antioxidants available from Ciba (sometimes they are also phenol derivatives).

Electric insulation layer and electric cable

According to the present invention, the electrically insulating layer may typically be a porous, fibrous and / or laminated structure, such as preferably a cellulose or paper fiber based tape.

"Laminated structure" refers to a structure comprising three or more layers, wherein the intermediate layer is based on cellulose or paper fibers and the two remaining layers comprise different layers such as an atactic polypropylene layer (i.e., Propylene layer).

The electrically insulating layer of the present invention is impregnated with an insulating solvent so that almost all the voids of the electrically insulating layer are filled with insulating impregnation solvent.

In a specific embodiment, when using a porous and / or fibrous structure (e.g., kraft paper) or other non-laminated structure, the gel point of the inventive organic gel is between 45 ° C and 80 ° C, more preferably between 50 Deg.] C to 75 [deg.] C, and most preferably 55 [deg.] C to 65 [deg.] C.

When a laminated structure is used, the gelation point of the organic gel of the present invention can be from 80 캜 to 90 캜.

In a specific embodiment, an electrical cable according to the present invention comprises: a first semiconductive layer surrounding the conductor; an insulating layer surrounding the first layer; A second semiconductive layer surrounding the insulating layer, and a protective shield surrounding the second layer. Optionally, the metal screen may be positioned along the electrical cable between the second semiconductive layer and the protective shield.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be more fully understood from the following detailed description and the accompanying drawings, which are given by way of illustration only and are not intended to limit the present invention.

1 shows a DC cable extending from the center to the outside in the following manner.

- a twisted multi-wire conductor (10);

- a first semiconductive shield (11) arranged around the conductor (10);

A wound and impregnated electrically insulating layer (12) comprising an insulating solvent according to the invention;

- a second semiconductive shield (13) disposed outside the electrically insulating layer (12);

- a metal screen (14) around a second semiconductive shield (13); And

A protective shield (15) disposed outside the metal screen (14).

The DC cable may be a single conductor DC cable having a multi-wire core as shown in Fig. 1, or a DC cable having two or more conductors. A DC cable comprising two or more conductors may be arranged in a flat cable arrangement or in two conductor arrangements, i.e. coaxial two-conductor cables, having one first central conductor surrounded by a concentric second outer conductor, May be any known type having conductors arranged side by side.

Figure 1 shows a schematic view of an embodiment of a DC cable according to the invention, which is preferred for use as a cable for power transmission. For purposes of clarity, only the components essential to understanding the present invention are shown schematically and no scale is used.
FIG. 2 shows the storage elastic modulus G 'and the loss elastic modulus G "curves, respectively, as well as the composite viscosity? * Curves for temperature in the case of the organic gel according to the present invention.

Example

In order to illustrate the advantages of the electric cable of the present invention, the visual aspects of various organic gels according to the prior art and the present invention were tested.

The various properties of the oils used to prepare the organic gels are shown in Table 1 below.

Oil and its properties Nyflex 200
(Nynas S8,5) Nyflex 222B
(Nynas S100B) Nyflex 800
(Nynas NS8) Nytex 801
(Nynas T9) Nytex 820
(Nynas T110) Heptamethyl nonane Oil type Hydrotreated naphthene Hydrotreated naphthene Hydrotreated naphthene Hydrotreated naphthene Hydrotreated naphthene Isoparaffin Viscosity at 40 캜 according to ASTM D 445 (cSt) 8.6 102 7.7 9.1 114 3.0 Flash point according to ASTM D 93A (℃) 144 218 144 146 212 95 C _A (%)
ASTM D 2140 Specification 3 <1 5 9 12 Not measured by ASTM test

The oils mentioned in Table 1 are commercially available from Nynas except for heptamethyl nonane (CAS 4390-04-9), a non-aromatic oil available from sources such as Aldrich.

The preparation of various organic-gelling agents and organic gels is described below. The separated material was characterized by NMR and MALDI-TOF-MS spectroscopy, and the analytical data were consistent with the corresponding structure.

Preparation of bis-urea substituted toluene

The bis-urea substituted toluene can be produced by the following reaction scheme:

The purity of 2,4-toluene diisocyanate or tolylene-2,4-diisocyanate (TDI) used in the experiments described in detail below is 95%. According to the requirements of the supplier (Aldrich T39853; CAS 584-84-9), about 4% of 2,6-toluene diisocyanate isomers are included. As a result, the bis-urea (or diurea) products described from TDI also typically contain a small proportion of 2,6-diureido isomers of about 4%.

Alternatively, industrial grade tolylene-2,4-diisocyanate (TDI) (Aldrich 216836, purity 80% according to the specification of the supplier) and the remaining 20% is tolylene-2,6-diisocyanate isomer ) Can be used, or an 80% grade TDI and a 95% grade TDI can be mixed in a predetermined ratio to obtain the selected reactants. In this way, the ratio of 2,6-isomers in the bis-urea product can be controlled.

Organic-Gelling Agent 1 (OG1):

The synthesis of 2,4-bis (2-ethylhexylureido) toluene (EHUT) in which R = R 1 = R 2 = (R / S) -2-ethyl-hexyl is described in Langmuir, 2002, 18, 7218-7222 Toluene-diisocyanate and racemic 2-ethyl-hexylamine in accordance with known procedures.

Thus, this organo-gelling agent OG1 can be prepared by reacting four different 2,4-bis- (2-ethylhexylureido) toluene isomeric compounds (R, R-, S, S-, R (R, R, S, S- and R, S) as well as a small amount of three different 2,6-bis- (2-ethylhexylureido) toluene isomer compounds -Isomer). Thus, OG1 consists of a total of seven compounds, where the 2,4-isomer is an example of formula III and the 2,6-isomer is an example of formula II. Both the 2,4- and 2,6-isomers are di-ureas with two urea groups attached to the meta-position on the benzene ring.

Organic-Gelling Agent 2 (OG2):

The synthesis of 2,4-bis (1,5-dimethylhexylureido) toluene (DMHUT) in which R = R1 = R2 = (R / S) Toluene-diisocyanate and racemic &lt; RTI ID = 0.0 &gt; 1, 5-dimethyl-hexylamine &lt; / RTI &gt; Similar to OG1, OG2 consists of a mixture of organo-gelling agent compounds.

Organic-Gelling Agent 3 (OG3):

Synthesis of 2,4-bis (3,7-dimethyloctylureido) toluene (DMOUT) with R = R1 = R2 = (R / S) -3,7-dimethyl- And racemic 3,7-dimethyl-octylamine in a manner analogous to that mentioned above for OG1 and OG2. The product is a white solid. Racemic 3,7-dimethyl-octylamine is not commercially available and is produced in two steps from racemic citronolol according to the procedure of Tetrahedron , 61, 2005, 687-691. Similar to OG1, OG3 consists of a mixture of organo-gelling agent compounds.

Organic-Gelling Agent 4 (OG4):

Organic-gelling agents EHUT (OG1) and DMHUT (OG2) were mixed in a weight ratio of 4: 1. The mixture was dissolved in a mixture of chloroform and methanol and homogenized, and then these solvents were again removed by vacuum evaporation. The product is a white solid.

Organic-Gelling Agent 5 (OG5) :

EHUT (OG1) and DMOUT (OG3) were mixed in a one-to-one weight ratio in a manner similar to that described for the preparation of OG4 (i.e., homogenization step).

Organic-gelling agents 6, 7 and 8 (OG6, OG7 and OG8):

Methabis-urea benzene EHUM, such as 2,4-bis (2-ethylhexyl ureido) -methylaniline as set forth below, activates racemic 2-ethylhexylamine with carbonyldiimidazole (CDI) , An excess of the resulting product was reacted with 1,3,5-trimethyl-2,4-diaminobenzene. Alternatively, the bis-urea EHUM can be prepared according to the method described in J. Phys. Chem . B, 2009, 113, 3360-3364).

Due to the racemic nature of the starting material, 2-ethylhexylamine, EHUM consists of a mixture of stereoisomers.

(OG6), 70 to 30 (OG7), and 80 (EGUM) in a manner similar to that described for the preparation of OG4 (by reference, homogenization step) And 20 (OG8), respectively.

Preparation of organic gel from OG1 to OG8

Organic gel formation from OG1 to OG8 in oil as shown in Table 1 can be achieved by stirring the oil and organo-gelling agent at high temperature (about 80 deg. C to 120 deg. C, typically 100 deg. C) overnight or for several hours, After cooling, the solution was inspected and tested.

result

Successful Organic Gel Production

Using OG1, a clear, macroscopically homogeneous and stable 5 w / w% and 10 w / w% organic gel in heptamethyl nonane, Nynas S8, 5 and Nyflex 800, were produced. In addition, 2.5 w / w% and 15 w / w% organic gels were generated in heptamethyl nonane.

A vial containing these OG1-organic gels could be placed upside down and no gel-solution flow was observed. For a period of several hours, the organic gel is viscoelastic and can record the flow. The 5 w / w% organic gel has elastic properties, while the 10 w / w% organic gel is also elastic, but its properties are harder.

The 5 w / w% organic gel from OG1 in Nynas S8, 5 and heptamethylnonane was monitored for at least two and a half years and was stable because no flow occurred even when the vial was inverted and the organic gel was clear, No bleeding was observed and no stirring or bleeding occurred even with stirring using a pipette in an organic gel.

In addition, OG2, OG3, OG4 and OG5 were used to generate a clear, stable and homogeneous 5 w / w% organic gel in heptamethyl nonane, Nynas S8, 5 and Nyflex 800, OG3 in 5 N / % &Lt; / RTI &gt; organic gel. Finally, OG6, OG7 and OG8 were used to generate 5 w / w% organic gel in Nynas S8,5.

Typically, the stirred mixture of organo-gellant and used oil has already been swollen at room temperature, but stirring at high temperature is necessary to quickly and easily obtain a homogeneous gel.

Manufacture of unsuccessful organic gel

The organo-gelling agents OG1 and OG3 could not be adequately dissolved in Nynas S100B or Nynas T110 oil at high temperatures and did not dissolve even after further heating to about 120 ° C and further precipitation occurred upon cooling, A heterogeneous mixture was produced.

Preparation of benzene-1,3,5-tricarboxamide (BTA)

Benzene-1,3,5-tricarboxamide can be produced according to the following reaction scheme:

Organic-Gelling Agent 9 (OG9):

N, N ', N'-tri- (3,7-dimethyloctyl) -benzene-1,3,5-tricaryl, where R = R4 = R5 = R6 = synthesis of carboxamide (DMO-BTA) can be carried out from benzene-1,3,5-tricarboxylic acid chloride, racemic 3,7-dimethyloctyl amine and triethyl amine. literature [Chem to the similar synthetic Lett ., 2000, 292-293.

Thus, these organo-gelling agents consist of four different BTA-compounds, S, S, S-, S, S, R-, S, R, R- and R, R, R-isomers. These BTAs are examples of formula VII.

Organic-Gelling Agent 10 (OG10):

R = R4 = R5 = R6 = N, N ', N "-tri- (3,7-dimethyloctyl) -benzene-1,3,5-tricarboxamide (SSS-DMO-BTA) can be carried out from benzene-1,3,5-tricarboxylic acid chloride, (S) -3,7-dimethyloctylamine and triethylamine. Chem . Lett , 2000, 292-293.

Thus, this organo-gelling agent consists of the S, S, S-isomer, which is the only BTA-compound.

Organo-gelling agent 11 (OG11):

The six different benzene-1,3,5-tricarboxamides (BTA) can be obtained individually in the form of R 4 = R 5 = R 6 = n-butyl (C 4 -BTA), n-hexyl C8-BTA), n-decyl (C10-BTA), n-dodecyl (C12-BTA) or n-tetradecyl (C14-BTA). See, for example, Bull. Chem. Soc. Jpn ., 61, 207-210, 1988).

Organic-gelling agent OG11 was produced by mixing C4-BTA, C6-BTA, C8-BTA, C10-BTA, C12-BTA and C14-BTA at a constant molar ratio.

Organic-Gelling Agent 12 (OG12):

Organic gelling agents OG12 was produced by the reaction mixture of the primary amine R-NH ₂ chloride, benzene-1,3,5-tricarboxylic acid in the presence of triethylamine base.

Using this approach, a rather statistical mixture of benzene-1,3,5-tricarboxamide (BTA), in which the R ⁴ , R ⁵ and R ⁶ groups may or may not be different from each other, may be obtained. Altering the molar ratio of the different primary amine R-NH ₂ reactants can modulate individual BTA-molecular structures in the BTA-product mixture.

In the case of OG12, five primary amine reactants, n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine and cyclohexylamine were used in a 1: 1: 1: 1: 4 molar ratio . After aqueous extraction with chloroform and purification by silica column chromatography, the separated organo-gellant material was a white solid.

Organo-gelling agent 13 (OG13):

The organo-gelling agent was prepared in a similar manner to OG12. Here, the five primary amine reagents n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine and racemic 2-ethylhexylamine were used in a 1: 1: 1: Respectively. The separated organo-gelling agent was a white solid material.

Preparation of organic gel from OG9 to OG13

In a manner analogous to OG1 to OG8, the organic gel formation of OG9 to OG13 in the oil described in Table 1 was carried out by stirring the oil and organo-gelling agent at high temperature (about 80 DEG C to 100 DEG C) overnight or for several hours, And the solution was irradiated and tested.

result

Successful Organic Gel Production

A stable, clear, homogeneous 5 w / w% organic gel was generated from the organic-gelling agent OG9 in heptamethyl nonane, Nynas S8,5, Nyflex 800 and Nynas T9 oil.

A solution of 5 w / w% OG11 in Nynas S8, 5 and Nyflex 800 was clear and very viscous whereas a 5 w / w% solution of OG12 and OG13 in Nynas S8.5 and Nyflex 800 produced a clear gel.

Manufacture of unsuccessful organic gel

The organo-gelling agents OG9 and OG10 could not be properly dissolved in Nynas S100B or Nynas T110 oil at high temperature and further precipitation occurred upon cooling, which resulted in a heterogeneous mixture at room temperature.

Other organic-gelling agents

Organic-Gelling Agent 14 (OG14): 1-Benzyl-3-octylurea

n-octyl isocyanate (1.38 g) was added to a solution of benzylamine (1 g) in toluene (50 mL). The reaction mixture was stirred overnight at room temperature under an inert nitrogen atmosphere and then diluted with hexane to induce precipitation of the white product. After the solid was collected by filtration, it was washed with several portions of hexane and dried.

Organic-Gelling Agent 15 (OG15):

3,4-Dimethyldibenzylidene sorbitol (DMDBS, CAS 135861-56-2) can be purchased from suppliers such as Alichem or APAC Pharmaceuticals.

Organic-Gelling Agent 16 (OG16):

Dibenzylidene sorbitol (DBS, CAS 19046-64-1) is available from suppliers such as Alichem or APAC Pharmaceuticals.

Organic gel preparation from OG14, OG15 and OG16

Organic-gelling agents OG14, OG15 and OG16 were not soluble in Nynas T110 or Nynas S100B oils. Stirring at room temperature did not exhibit swelling or thickening of the mixture and then did not dissolve either by heating to about 100 ° C and then heating above 100 ° C (120 ° C for OG 14 and 180 ° C for OG 15 and OG 16) And after cooling to room temperature, a suspension of organic-gelling agent and oil was obtained. OG14 was tested at the 5 w / w% level, while OG15 and OG16 were tested at the 2 w / w% level.

Preparation of insulating solvents containing organic gel and further components

BHT (butylhydroxytoluene; 2,6-di-tert-butyl-4-methylphenol, CAS 128-37-0), a known antioxidant and stabilizer, was stirred at room temperature in Nynas S8, w% BHT solution. The solution and the appropriate amount of EHUT (OG1) were stirred at room temperature (swelling observed) and then stirred at about 100 DEG C for several hours. Cooling to room temperature resulted in a clear 5 w / w% insulation solvent containing BHT antioxidant. In the same manner, a 5 w / w% organic gel of OG1 in Nyflex 800 was produced with 0.2 w / w% BHT. Similarly, a clear insulating solvent was obtained.

PIB (polyisobutylene / butene copolymer: Indopol H-100 from BP, CAS 9003-29-6, viscosity 196-233 cSt at 99 DEG C, Mn = about 920) was stirred at room temperature in Nyflex 800, 0.25 w / w% PIB solution. The solution and the appropriate amount of EHUT (OG1) were stirred overnight at about 80 DEG C and then cooled to room temperature to produce a clear 5 w / w% insulation solvent containing PIB and OG1-organic gel.

Gelation point measurement of 5 w / w% organic gel of EHUT (OG1) in Nyflex 800

The gelling point was measured with a Brookfield flow meter. Viscosity measurements were made at 4 ° C to 110 ° C at 0.5 ° C / min under 0.095 Hz vibration and under 1% strain.

Figure 2 shows the storage modulus G 'and the loss modulus G "curves, respectively, as well as the composite viscosity for the temperature of the 5 w / w% organic gel of EHUT (OG1) in Nyflex 800.

The gelation point of the organic gel is the intersection of the G 'curve and the G' curve at 55 ° C to 60 ° C.

According to the composite viscosity (? *) Curve, the composite viscosity drop between 45 占 폚 and 90 占 폚 ranges from about 800 占 퐏 ec to less than 0.2 占 퐏 ec, and the composite viscosity drop greater than 30 and greater than 500? Respectively.

Gelation point measurement of 5 w / w% organic gel of OG6, OG7 and OG8 in Nynas S8,5 oil

The gelation points of 5 w / w% organic gels of OG6, OG7 and OG8 in Nynas S8,5 oil were measured in a manner similar to that for 5 w / w% gel of OG1 in Nyflex 800 and the following results were obtained.

OG6 (EHUT vs. EHUM = 60 to 40 wt.) Gel showed a gelation point at 86 DEG C while OG7 (EHUT vs. EHUM = 70 to 30 wt.) Showed a gelation point at 78 DEG C and OG8 (EHUT vs. EHUM = 80 20 wt.%) Showed a gelation point at 71 ° C.

These results indicate that the gel point of the gel can be controlled by mixing various organic-gelling agents.

Composite viscosities (? *) Flatness, i.e., the composite viscosity at temperatures lower than the gelation point, was observed at about 1,000 to 2,000 Pa.s for three gels (OG6, OG7 and OG8) Was recorded at about &lt; RTI ID = 0.0 &gt; 110 C &lt; / RTI &gt; for the three gels. In addition, the composite viscosity drop in the three prepared gels was greater than 30 and greater than 500 Pa.s within 30 ° C.

Nyflex Of 800 Of EHUT (OG1)  5 w / w% From the organic gel Impregnated  Electricity Insulating layer  Produce

The impregnation step known in the prior art consists of applying an insulating paper tape around the conductor and impregnating the tape.

More specifically, an insulated paper tape was wound around the conductor to form an electric cable, which was placed in a container in the presence of an organic gel. The step of impregnation into the vessel was carried out at a temperature higher than the gelation point of the organic gel (higher than 60 DEG C). The temperature range allows for optimization of impregnation from the organic gel to the insulating paper. Thereafter, the excess organic gel was pumped through the heat exchanger in the vessel, the vessel cooled, and the impregnated insulating paper tape was obtained.

The organic-gelling agent EHUT (OG1) can stably gel non-polar Nynas oil, since the impregnated insulating paper tape does not exhibit bleeding even after standing for 6 months (i.e., Phase separation between the gel phases).

Nyflex 800 Of EHUT (OG1)  5 w / w% From the organic gel Impregnated  Electricity Insulating layer  Measurement of breakdown voltage

Breakdown voltage of organic gel was measured according to IEC 156 standard. The high breakdown properties of the insulating paper impregnated with the organic gel were obtained using two electrodes with three layers of impregnated DC-paper each of 70 microns between the two electrodes. Using a Haefely DC generator, a voltage step of 5 kV was applied (for 1 minute) until a DC breakage occurred in the impregnated insulating paper tape. DC breakdown was measured at 60 ℃ and DC breakdown occurred at higher than 200 ㎸ / ㎜.

Claims (21)

(10) and an electrically insulating layer (12) impregnated with an insulating solvent, wherein the insulating layer (12) surrounds the conductor (10) and the insulating solvent comprises an oil and an organo-gelling agent Wherein the oil is a nonpolar oil having a flash point of 200 ° C or less and the organic-gelling agent is a molecule that self-assembles in solution by supramolecular interaction to form a supramolecular structure. . The method according to claim 1,
Wherein the oil has a flash point of 95 ° C or higher. 3. The method according to claim 1 or 2,
Wherein the oil has an aromatic compound content (CA) of less than 12% according to ASTM D 2140. The method according to claim 1,
Wherein the oil is selected from naphthenic oil, paraffin oil and isoparaffin oil, or mixtures thereof. The method according to claim 1,
Wherein the organic-gelling agent comprises a mixture of two or more organic-gelling agent compounds. The method according to claim 1,
Wherein the organic-gelling agent is selected from a urea-based compound, a mixture of urea-based compounds, a mixture of an amide-based compound and an amide-based compound, or a mixture thereof. The method according to claim 6,
Wherein said urea-based compound is selected from a mixture of monourea or mono-urea, a mixture of bis-urea or bis-urea and a mixture of tris-urea or tris-urea. The method according to claim 6,
Wherein the urea compound is bis-urea-substituted toluene. The method according to claim 6,
Wherein said amide-based compound is selected from a mixture of diamides or diamides, a mixture of triamides or triamides, and a mixture of tetramides or tetramides. The method according to claim 6,
Wherein the amide compound is an aromatic tricarboxamide. 11. The method of claim 10,
Wherein the aromatic tricarboxamide is benzene-1,3,5-tricarboxamide. The method according to claim 6,
When the urea compound is substituted with two or more different R- groups, the urea compound is an asymmetric urea compound. The method according to claim 6,
When the amide-based compound is substituted with two or more different R-groups, the amide-based compound is an asymmetric amide-based compound. The method according to claim 1,
Wherein the organic gel has a gelation point of 45 占 폚 to 90 占 폚. The method according to claim 1,
Characterized in that said organic gel comprises up to 20% by weight of an organo-gelling agent. The method according to claim 1,
Comprising a first semiconductive layer (11) surrounding the conductor (10), an insulating layer (12) surrounding the first layer (11), a second semiconductive layer (13) and a protective shield (15) surrounding said second layer (13). The method according to claim 1,
Wherein the organic-gelling agent is a non-polymeric organic compound. The method according to claim 1,
Characterized in that the viscosity of the oil is less than 40 cSt (centistokes) at 40 占 폚. The method according to claim 1,
Characterized in that the flash point is measured by the Pensky Marten (PM) closed cup method ASTM D 93 A. The method according to claim 1,
Characterized in that the molecular weight of the organo-gelling agent is less than 5,000 daltons. Claims 1. A method for making a conductor (10) comprising at least one conductor (10) and an electrically insulating layer (12) impregnated with an insulating solvent, the insulating layer (12) surrounding the conductor (10) Wherein the oil is a non-polar oil having a flash point of 200 캜 or less, and the organic-gelling agent is a non-polymeric organic compound.

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