NO802166L - POLYMER MATERIALS WHICH ARE RESISTANT TO CRYSTAL DAMAGE DAMAGE. - Google Patents

Description

This invention relates to polymer materials with increased resistance to "wood-like" breakdown of the structure caused by electric current and water, respectively. The polymer gauge materials are applicable for the insulation of electrical cables.'

US Patent No. 4,144,202 describes precautions

against breakdown of the electrical insulation capacity of dielectric materials based on ethylene polymers as a result of what could be called "treeing", namely "tree-like" or "tree-patterned" breakdown of the materials' structure. The patent describes the types of electrical failure that are the result of "tree formation" and explains the term "tree formation" and some of the causes of this tree formation. When the polymer structure breaks down, the damage will typically propagate through the insulating or dielectric material in a tree-like path. This "tree formation"

is usually a failure that happens slowly, and it can take many years before it causes a failure of the insulation.

Polymer materials are well known and are widely used as insulating materials for wires and cables. Used as an insulating material, it is important that the material has certain physical and electrical properties, such as resistance to mechanical cutting, resistance to crack formation

etc. as a result of voltage stresses and resistance to dielectric failure. Recently published publications have shown that water-induced wooding and electricity-induced wooding in the insulation are particularly important problems, because they are associated with, if not solely responsible for, dielectric failure.

An important area of application for insulating materials is high-voltage transmission and distribution cables, especially earth cables. Three types of wooding have been observed in power lines, namely electricity-induced wooding, water-induced wooding and electrochemical wooding. It is commonly assumed that electricity-induced wood formation occurs by corona discharges which cause melting and breakdown of the polymer, while water-induced wood formation usually occurs in cables that are buried in moist ground. The water-caused wood-like patterns have a different appearance than the electricity-caused wood-like patterns. The electrochemical wood-like patterns resemble the water-induced wood-like patterns but are characterized by the presence of metal ions in the wood pattern.

According to the above-mentioned US patent no. 4,144,202, water-induced wood formation in ethylene polymer materials is prevented by the incorporation of certain organosilane compounds. In particular, the organosilane is a silane containing an epoxy-containing radical. Suitable polymers, additives and production processes for the production of the material are described in the patent document.

US patent applications Nos. 709,266 and 809,910 relate to insulating materials which are particularly suitable for high-voltage power lines. They contain an effective amount of an alcohol with from 6 to 24 carbon atoms, which gives the materials resistance to electricity-induced wood formation. These patent applications, like the above-mentioned US patent document no. 4,144,202, contain an explanation of the problem of electricity-induced wood formation in polymer materials and refer to a number of patent documents that describe attempts to solve the problem. Suitable polymers, additives and manufacturing processes are described in these US patent applications.

In DE-OS 2-737 430 it is stated that the addition of certain alkoxy-silanes to polyolefin insulation materials prevents water-induced wood formation. Several trimethoxy and triethoxysilanes are stated to be useful. No AlkoxyAlkoxysilanes are stated or implied to have an inhibitory effect on both water-induced wood formation and electricity-induced wood formation.

US Patent No. 3,553,348 and British Patent Nos. 1,248,256 and 1,277,378 relate to mineral-filled polymer materials suitable for insulating electrical wires and cables. The mineral filler is treated with an organosilane, such as an alkyl alkoxy silane or a vinyl alkoxy silane to reduce the porosity of the material. None of these patents states or suggests that the addition of an organosilane to an unfilled polymeric material will improve the polymeric material's resistance to water-induced or electricity-induced wood formation.

Until now, it has not been possible in the field to provide an insulation material with improved resistance to both water-induced wood formation and electricity-induced wood formation. As indicated in the above-mentioned US patent 4,144,202, the actual electrical breakdown, failure due to corona discharges, electricity-induced wood formation and water-induced wood formation are different phenomena. The mechanisms that apply in these are different, and different solutions are required for the different types of failure that can occur in a dielectric material. There is therefore a great challenge in finding a material that is able to resist both electricity-induced wood formation and water-induced wood formation.

It has now surprisingly been found that polymer materials containing an effective amount of certain organic compounds, namely certain silane compounds, exhibit improved resistance to both water-induced wood formation and electricity-induced wood formation. The material can also be hardened using known methods into a cross-linked material which has improved properties for certain applications.

Usually the polymer material contains per 100 parts by weight (phr) of polymer between 0.1 and 10 phr of a silane of the formula

A:

where R, R.sub.2, R.sub.2 and R.sub.2 are independently selected from among alkyl with 1-8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such group, aryl with 6-18 carbon atoms or a substituted such group, hydrogen, halogen, an epoxy-containing radical, alkenyl with 2-8 carbon atoms, a nitrogen-containing radical, a carboxy-group-containing radical, a mercapto-group-containing radical and an ether-group-containing radical, with the proviso that at least one, and preferably at least three of the substituents R, R.sup.2, R.sup.2 and R.sup.3, e.g. all of them are a group

which contains at least one electron-donating atom in the chain and is in a different position than the neighboring position of the silicon atom. The electron-donating group can e.g. be oxygen, nitrogen, sulfur and the like. Oxygen is preferred because of its effectiveness. A highly preferred group has the electron donating atom separated from the silicon atom by three atoms.

A preferred material contains from 0.5 to 5 phr of silane component, most preferably from 1 to 3 phr.

A particularly preferred non-filled polymeric material comprises a homogeneous mixture of a polymeric component and an effective amount of an agent that counteracts water-induced wood formation and electricity-induced wood formation, namely an organic compound of the following formula B:

where R^, R^ and R^ are the same or different and denote Yl ^nH2n^ Y2^6'-^^yl mec^ 1~8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such aryloxy group, aryl with 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen, an epoxy group-containing radical, alkenyl with 2-8 carbon atoms, a nitrogen-containing radical,

a carboxy group-containing radical, a mercapto group-containing radical or an ether group-containing radical; R^ is alkyl of 1-8 carbon atoms, alkoxy of 1-8 carbon atoms, acyloxy of 1-8 carbon atoms, aryloxy of 6-18 carbon atoms or a substituted such aryloxy group, aryl of 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen, an epoxy group-containing radical, alkenyl of 2-8 carbon atoms, a nitrogen-containing radical, a carboxy group-containing radical, a mercapto group-containing radical or an ether group-containing radical; and Y~ are the same or different and are 0, S or N; Z is Si, Sn, Ti, P or B; a is 0 or 1 and n is from 1 to 8.

This particularly preferred material contains from 0.1

to 10 parts by weight of the organic compound of formula B

per 100 parts by weight polymer. A particularly preferred material contains from 0.5 to 5 phr of the organic compound, preferably from 1 to 3 phr.

The invention also relates to a method for stabilizing an electrical conductor insulated with a polymer material against wood formation caused by water and electricity

cause wood formation, in which method an electrical conductor is coated with an effective insulating amount of a polymeric insulating material comprising a homogeneous mix-

ing of a polymer component and an effective amount of an agent that counteracts water-induced wood formation and electricity-induced wood formation, namely an organic compound of the following formula B:

where R^, R2 and *R3 are the same or different and denote Yl^CnH2ri) Y2R6'alk^1 with 1-8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such aryloxy group, aryl with 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen, an epoxy group-containing radical, alkenyl with 2-8 carbon atoms, a nitrogen-containing radical,

a carboxy group-containing radical, a mercapto group-containing radical or an ether group-containing radical; Rg is alkyl with 1-8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such aryloxy group, aryl with 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen , an epoxy-group-containing radical, alkenyl with 2-8 carbon atoms, a nitrogen-containing radical, a carboxy-group-containing radical, a mercapto-group-containing radical or an ether-group-containing radical; Y-^ and Y2 are the same or different and are O, S or

N; Z is Si, Sn, Ti, P or B; a is 0 or 1 and n is from 1

to 8,

whereby the insulated electrical conductor will be protected against water-induced wood formation and electricity-induced wood formation when exposed to environments that may give rise to water-induced wood formation and electricity-induced wood formation.

The materials according to the invention are particularly applicable

in connection with high-voltage transmission and distribution cables,

but they are also applicable to other electrical applications where there will be a need for a unique combination of improved properties in terms of water-induced wood formation and electricity-induced wood formation.

The polymers which are applicable in connection with the invention include basically any normally solid syn-

thetic, organic, polymeric thermoplastic resin. Examples are polyolefins and copolymers thereof, vinyl polymers, olefin-vinyl copolymers, olefin-allyl copolymers, polyamides, acrylic polymers, polystyrenes, cellulose plastics, polyesters and fluorocarbons.

The polyolefins normally include solid polymers of olefins, especially mono-α-olefins, containing from 2 to 6 carbon atoms, e.g. polyethylene, polypropylene, polybutene, polyisobutylene, poly (4-methyl-pentene). and such. Pre-

drawn polyolefins are polyethylene and polypropylene. Poly-

ethylene is particularly preferred. A polyethylene which is quite particularly preferred, because of its high efficiency, is sold under the trademark "NA 310" by the National Distillers and Chemical Company.

Copolymers of ethylene and other compounds which allow

polymerize together with ethylene, such as butene-1, pentene-1, styrene and the like, can also be used. Usually the ethylene will contain from 50 to 100% by weight of ethylene.

Suitable vinyl polymers include polyvinyl chloride, polyvinyl acetate, vinyl chloride/vinyl acetate copolymers, polyvinyl alcohol and polyvinyl acetal.

Suitable olefin-vinyl copolymers include ethylene-vinyl acetate, ethylene-vinyl propionate, ethylene-vinyl isobutyrate, ethylene-vinyl alcohol, ethylene-methylacrylate, ethylene-ethylacrylate, ethylene-ethylmethacrylate and the like. Usually the ethylene makes up at least 25% by weight of the copolymer.

The olefin-allyl copolymers include ethylene-allyl-benzene, ethylene-allyl ether, ethylene-acrolein and the like.

The silane used in the polymer materials according to the invention can be one or more compounds of the following formula A:

where R, R^, R^ and R^ have the meanings given above in connection with formula A.

The organic compound used in the particularly preferred non-filled polymer materials according to the invention is one or more compounds of the following formula B:

where R^, R2, R3, Rg, Y^, Y2, Z, a and n are as indicated above in connection with formula B.

Several of the groups R, R-^, R2 and R3 which are applicable in connection with the invention are discussed on page 43 of "Chemicals and Plastics Physical Properties. 1978-80" published by the Union Carbide Company. Examples are chlorine, methyl, ethyl, methoxy, ethoxy, phenyl, hydrogen, chloropropyl, vinyl-2-methoxyethoxy, Y-methacryloxypropy 1 (i-(3,4-epoxycyclohexyl)-ethyl, Y-glycidoxypropyl, acetoxy, Y-mercaptopropyl , Y-aminopropyl, bis-hydroxyethyl-γ-aminopropyl, bis-acrylic acid-Y-aminopropyl, N-3-(aminoethyl)-Y-aminopropyl, and methyl-[2-(Y-trimethoxysilylpropylamino)-ethylamino]-3- propionate.

As indicated above, at least one of the groups R, R 1 , R 2 and R 2 has

Rt in formula A is an electron donating atom, such as an oxygen, nitrogen or sulfur atom in the chain. Preferably, the electron donating atom is separated from the silicon atom by three atoms. A preferred group has the following formula: where R 1 is alkyl of 1-6 carbon atoms and R 1 - is alkyl of 1-8 carbon atoms, hydrogen, alkoxy of 1-8 carbon atoms or alkenyl of 2-8 carbon atoms. A particularly preferred group is 2-methoxyethoxy, having the formula

A preferred compound is sold under the trade name "A-172" by the Union Carbide Company and its chemical name is vinyl-tris-(2-methoxyethoxy)-silane. Examples of other groups R, R1, R2 and R- are Y-methacryloxy-propyl-Y-glycidoxypropyl, Y-aminopropyl, bis-hydroxy-ethyl-Y-aminopropyl and N-3-(aminoethyl)-Y-aminopropyl.

The groups R 1 , R 2 and R 2 in formula B which are useful in connection with the invention when Z is silicon, are e.g.

the groups mentioned above in connection with the publication of the Union Carbide Company, especially when Y 2 .(cnH 2 n^ Y 2 R 6 is an alkoxy alkoxy group. Among applicable silanes of formula B can be mentioned Y-methacryloxypropyl-tris-(2-methoxyethoxy)-silane, tetrakis-(2-methoxyethoxy)-r-silane, methyl-tris-(2-methoxyethoxy)-silane, phenyl-tris-(2-methoxyethoxy)-silane, vinyl-tris-(2-phenoxyethoxy)-silane, vinyl- tris-(2-methylthio-ethoxy)-silane and vinyl-tris-(2-methoxyethoxy)-silane, among which the latter is particularly preferred. By replacing the silicon atom with atoms such as tin, titanium, phosphorus or boron, other compounds are obtained such as are applicable in connection with the invention. Thus, compounds such as tris-(2-ethoxyethyl)-phosphite, tris-(2-n-butoxyethyl)<-phosphite, tetra-kis-(2-methoxyethoxy)-titanium and the like can be used , and these are included within the scope of the invention.

In the preferred organic compounds of formula B, therefore, R , R 2 and R 3 are selected from Yi(cnH 2 n^Y 2 R 6'alkYl'alkoxY/

acyloxy, aryl or alkenyl, while Rg is alkyl or aryl,

Y1 and Y2 are 0 and Z is Si or P. Of course, when Z is Si, a is equal to 1, and when Z is P, a is 0.

When it is desired to use a polymer material which allows

cross-link, the cross-linking can be carried out using any of the known methods, such as using chemical agents, e.g. by peroxide cross-linking, by irradiation using electron accelerators, by means of Y-rays, high-energy irradiation, such as X-rays, by means of microwaves, etc. or by thermal cross-linking. The basic methods for crosslinking polymers are very well known in the art, and a detailed explanation of these is not considered to be required here.

Conventional cross-linking agents, such as organic peroxides, are suitable. Typical peroxide based organic free radical generators include dicumyl peroxide; 2,5-bis-(tert-butylperoxy)-2,5-dimethylhexane; di-tert-butyl peroxide; benzoyl peroxide; α,α'-bis-tert-butylperoxy)-diisopropyl-benzene and the like, as indicated in US Patent No. 3,287,312. The amount of organic peroxide, when such is used, will

be in the range from 0.5 to 5.0% by weight, based on the total weight of the material, or in the range from 0.5 to 10 phr, preferably from 3 to 6 phr. . Although the silanes and organic compounds described above are applicable to both thermoplastic materials and cured polymer materials, it is preferred, when the materials are to be cured, that one of the groups, i.e. R, R.sub.2, R.sub.2 or R.sub.2, is an organofunctional group, e.g. a vinyl group, which gives the material improved hardening properties.

Smaller amounts of other additives can also be used in conventional amounts to achieve the desired results. Conventional antioxidants, such as the sterically blocked phenols, polyquinolines and the like can be used. Other components that can be incorporated are plasticizers, dyes, pigments, heat and light stabilizers, antistatic agents and the like.

The preferred materials according to the invention are non-filled polymer materials. The term "non-filled", when applied to the present material, shall mean a material

which contains less than 10% of a conventional filler

for polymers. For certain applications and to meet particular specifications, the unfilled materials described herein may be free of fillers. The materials according to the invention may contain from 0 to 10% filler. Consequently, fillers, such as mineral fillers, can be used to this limited extent in the production of the materials according to the invention, but in the particularly preferred embodiments and for special applications, the materials do not contain fillers.

The polymer materials according to the invention can be produced

by mixing the different ingredients together. When the organic compound and the polymer component are mixed together to produce the present materials, the organic compound and the polymer component are homogeneously dispersed in each other. The order of the mixing operations and the details of the procedure used are not of decisive importance, except that from the time a peroxide is possibly added,

the temperature must be lower than approx. 130°C to prevent premature hardening of the material. However, this precaution is well known in the art.

The ingredients can be mixed in many different types of apparatus, including multi-roll mills, screw mills, continuous mixers, mixing extruders and Banbury mixers.

After being extruded onto a wire or cable, or onto another substrate, the crosslinkable materials are vulcanized at elevated temperatures, e.g. at temperatures above 180°C, using conventional vulcanization methods.

In order to determine the applicability and effectiveness of the polymer materials according to the invention with respect to the inhibitory effect on water-induced wood formation and electricity-induced wood formation, the materials were subjected to certain accelerated tests.

Tests for judging the electricity-induced wood formation were carried out using a method similar to that described in IEEE Conference Paper No. C73, 257-3 1973 by E.J. McMahon and J.R. Perkins. Material strips of width approx.

25.4 mm was cut from a 6.35 mm thick die-cast plate.

The block was machined so that a strip was obtained

with parallel side edges at a distance of 25.4 mm from each other. The strip was then cut into blocks with a side edge of 25.4 mm x 25.4 mm. A blunt needle and a sharp needle were pressed into opposite parallel side edges, at elevated temperatures, so that the needle tips were spaced 3.175 mm apart. The insertion of the needle and the cooling of the test piece were carried out slowly to avoid creating thermal or mechanical stresses in the test piece. The sharp needle had a tip diameter of approx. 0.00508 mm, while the diameter of the blunt needle was 0.0508 mm. Eight specimens were produced and tested simultaneously for each material. The test for judging electricity-induced wood formation was performed by energizing the sharp needle at 15 KV using a frequency of 60 Hz. The blunt needle was grounded. The time it took for each of the eight test pieces to fail as a result of wood formation, with subsequent electrical short circuit, was noted. The time it took for 50% of the test pieces to fail,

was used as a measure of the effectiveness of the tested wood formation inhibitor.

The test for assessing water-induced wood formation is carried out according to a method similar to that described in US patent document no. 4 144 202. A die-cast disc of diameter approx. 150 mm with 25 conical recesses were produced from each material. The shape of the disk and the dimensions of the recesses were mainly as shown in US Patent No. 4,144,202. The underside of the disk was sprayed with a silver paint that was to serve as the grounded electrode. A 152.4 mm long tube of acrylic plastic was clamped to the upper side of the disk, so that a test cell was formed. About. 150 ml of 0.01 N sodium chloride solution was poured into the cell, and the air bubbles that formed on the surface of the sample were removed. A ring of platinum wire was then immersed in the electrolyte and connected to the current source, which delivered 5 KV at a frequency of 3 KHz. The test pieces were energized for 22 hours, after which they were removed from the test cell and washed with distilled water. The ten centrally arranged depressions were cut out of the plate and colored to make the water-induced wood patterns more visible. Thin sections were prepared using a microtome. These were then examined microscopically (at 200 X) and the wood size measured. Normally, four slices of each test material were produced.

ale, so that the average tree size could be calculated from 40 individual measurements. For evaluation of the different wood formation-inhibiting agents, the relative wood size was

agreed by comparison with the average wood size obtained for a standard thermoplastic high-voltage insulating material containing no wood-inhibiting additives.

Different embodiments of the invention will now be illustrated in the following examples. Everyone. parts and percentages are on a weight basis, unless otherwise stated.

Example 1

The materials were prepared by grinding a commercial polyethylene ("NA 310") and the wood-inhibiting additive (2% by weight) in a two-roll mill at approx. 149°C for approx. 10 minutes, so that a homogeneous dispersion was obtained. The crab obtained was then used for the production of test pieces for testing with regard to electricity-induced wood formation and water-induced wood formation according to the methods described above. The test results are listed in Table I. All materials had the same composition, except for the anti-wood additive (listed in Table I ) and consisted of a commercial polyethylene with a melt index of from 0.20 to 0.35 g/10 minutes and a density of approx. 0.917g/litre. The control sample did not contain any wood-inhibiting additive.

The results clearly show the improvements achieved for the materials according to the invention with respect to both water-induced wood formation and electricity-induced wood formation. When comparing test pieces A and B according to the invention with test pieces 1-4, which fall outside the scope of the invention, the improvement is clearly visible. A comparison of sample A with control sample 1 shows the significant improvement in properties achieved when vinyl-tris-(2-methoxyethoxy)-silane is incorporated. In a similar way, a comparison of sample A with sample 2 shows the importance of using a silane with an electron-donating atom in the chain of the groups bound to the silicon atom. A comparison between sample A and sample B shows the advantage of using three electron-donating radicals bound to the silicon atom.

Example 2

In a similar way as in example 1, a number of organic compounds were evaluated as wood formation-inhibiting additives.

The investigations showed that the silanes which have alkyloxy-substituents have superior properties with regard to resistance to both water-induced wood formation and electricity-induced wood formation (test pieces 6, 9, 10, 14, 22 and 23). This can be seen, among other things, by comparing the silane pairs according to examples 6 and 7, 9 and 11 and 13 and 14. It also appears that an optimal number of alkyloxy-alkoxy substituents is given, cf. examples 6, 9 and 10. The effect of a vinyl substituent compared to the effect of an alkyl or aryl substituent is clear from a comparison of examples 6, 9 and 22. The position of a given substituent, here an aryl group, can affect the organic compound's inhibition properties, as will appear from a comparison of the test pieces' 22 and 23.

Test pieces 24 and 25 show that organic phosphites are effective in inhibiting both water-induced wood formation and electricity-induced wood formation, while test piece 26 shows a similar effectiveness for an organic titanium compound.

Although the invention has mainly been described

with reference to silanes, it will be clear to the person skilled in the art that other compounds containing a polyvalent atom, such as titanium, tin, phosphorus and the like, can also be used.

Claims (17)

1. Polymer material with improved resistance to "wood-like" degradation of the structure caused by water and electric current respectively, characterized in that it comprises a homogeneous mixture of a polymer component and, as an agent that inhibits the formation of water-induced and electricity-induced wood formation, an effective amount of an organic compound of the formula: where R^ , R2 and R^ are the same or different and denote Yl ^Cn H2 n^ Y2R6' ^^yl with 1-8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such aryloxy group, aryl with 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen, an epoxy group-containing radical, alkenyl with 2-8 carbon atoms, a nitrogen-containing radical, a carboxy group-containing radical, a mercapto group-containing radical or an ether group-containing radical; Rg is alkyl with 1-8 carbon atoms, alkoxy with 1-8 carbon atoms, acyloxy with 1-8 carbon atoms, aryloxy with 6-18 carbon atoms or a substituted such aryloxy group, aryl with 6-18 carbon atoms or a substituted such aryl group, hydrogen, halogen , an epoxy-group-containing radical, alkenyl of 2-8 carbon atoms, a nitrogen-containing radical, a carboxy-group-containing radical, a mercaptogroup-containing radical or an ether-group-containing radical, Y, and Y^ are the same or different and are 0, S or N; Z is Si, Sn, Ti, P or B; a is 0 or 1 and n is from 1 to 8, since the material also contains from 0 to 10% by weight of filler. 2. Material according to claim 1, characterized in that the polymer is polyethylene. 3. Material according to claim 1, characterized in that R 1 , R 2 and R 3 are each selected from <Y> 1( <C> n <H> 2n) Y 2 R 6' alkyl 1' alkoxy, ac yloxy, aryl and alkenyl; R g .is alkyl or aryl, and both Y1 and Y2 are 0. 4.. Material according to claim 3, characterized by Z is Si and a is 1. 5. Material according to claim 4, characterized in that R1 is vinyl, R2 and R3 are both Y, (c H,, ) Y„R,,, R£ is methyl and n is 2. i n at \ / b t> 6. Material according to claim 4, characterized in that R1 is methyl, R2 and R3 are both Y,(C H„ ) Y„R,, Rc is methyl and n is 2. 1 n 2n 2 6' 6 7. Material according to claim 4, characterized in that each of R^ R2 and R3 is Y1 (cn <H> 2n^ <Y> 2R6' Rg is methyl and n is 2. 8. Material according to claim 4, characterized in that is y-methacryloxypropyl, R2 and R3 are both Y1 (cn <H> 2n) Y2R6' R6 is ^^V1 and n is 2. 9. Material according to claim 4, characterized in that R1 is phenyl, R2 and R3 are both Yl ( <C> n <H> 2n) Y2R6» R6 is methyl and n is 2. 10. Material according to claim 4, characterized by R^ is vinyl, R2 and R3 are both <Y> l( <C> n <H> 2n) <Y> 2 <R> 6' <R> 6 is phenyl and n is 2. 11. Material according to claim 3, characterized in that Z is P and a is 0. 12. Material according to claim 11, characterized in that R-, and Rn are both Y, (C H„ ) Y0 R,, R, 12 " ln2n 26 .6 is ethyl and n is 2. 13. Material according to claim 11, characterized in that R, and R0 are both Y,(C H„) Y0R,, R, 12 3 1 n 2n 266 is n-butyl and n is 2. 14. Material according to claim 3, characterized in that Z is Ti and a is 1. 15. Material according to claim 14, characterized in that each of R^, R^ and R^ is Yi^cnH2n^ Y2 R6' Rg is methyl and n is 2. 16. Material according to requirements requirements 1-15, characterized by being hardenable or hardened. 17. Use of a material according to claims 1-16 as an insulating coating on an electrical conductor.