Use of a composition or thermosetting resin or thermoset polymer made therefrom as build-up film material in a printed circuit element

Abstract

Described herein is the use of a composition for making an insulating thermosetting resin, or of an insulating thermosetting resin or an insulating thermoset polymer thereof, where said composition comprises a curable component, comprising or consisting of a carbodiimide component and a cyanate ester component, and wherein the use is as electrical insulation or as electrical insulation material in a printed circuit element and / or as a buildup film material in a printed circuit element. Moreover is described a respective composition, insulating thermosetting resin or insulating thermoset polymer, as well as a layer composite, comprising a respective composition, insulating thermosetting resin or insulating thermoset polymer. Also described is a printed circuit element, comprising at least one insulating layer, comprising a respective composition, insulating thermosetting resin or insulating thermoset polymer, and a method of making said printed circuit element. It is furthermore described a pre-impregnated fiber article, comprising a respective insulating thermosetting resin as described herein.

Description

[0001] BASF SE

[0002] Carl-Bosch-StraBe 38, 67056 Ludwigshafen am Rhein

[0003] Germany

[0004] Use of a composition or thermosetting resin or thermoset polymer made therefrom as build-up film material in a printed circuit element

[0005] The present invention relates to the use of a composition for making an insulating thermosetting resin or of an insulating thermosetting resin or an insulating thermoset polymer thereof, where said composition comprises a curable component, comprising or consisting of a carbodiimide component and a cyanate ester component, and wherein the use is as electrical insulation or as electrical insulation material in a printed circuit element and / or as a build-up film material in a printed circuit element. Moreover, the present invention relates to a respective composition, insulating thermosetting resin or insulating thermoset polymer, as well as to a layer composite, comprising a respective composition, insulating thermosetting resin or insulating thermoset polymer. The present invention also relates to a printed circuit element, comprising at least one insulating layer, comprising a respective composition, insulating thermosetting resin or insulating thermoset polymer, and to a method of making said printed circuit element. The present invention furthermore relates to a preimpregnated fiber article, comprising a respective insulating thermosetting resin as described herein.

[0006] In recent years, much research has focussed on higher processing speeds and higher wiring densities for printed circuit elements (also known as printed circuit boards, “PCBs”), which are used in electronic appliances, communication apparatuses and similar devices. Accordingly, as a process for producing a multilayer printed circuit (or wiring) board, a production technique of a build-up system in which organic insulation layers (in particular in the form of “build-up films”) are alternately stacked on conductor layers of a circuit substrate, has received some interest. One line of research related to this subject has recently dealt with insulating materials with low dielectric loss tangent for reduction of transmission loss in multilayer printed wiring boards for electronic devices, e.g. for 5G applications:

[0007] Document WO 2018 / 164259 A1 deals with a resin material, a laminated film, and a multilayer printed wiring board.

[0008] In document CN 10410621 A, a thermosetting resin composition and a prepreg and a laminate using said resin are described.

[0009] Moreover, document JPH 02218751 A discusses a composition for a laminating material.

[0010] In document EP 3 260 501 A, a curable resin composition and a sealing material using the same are described.

[0011] Document JPH 0616829 A deals with a thermosetting resin-containing carbon fiber composite material.

[0012] In the light of the existing prior art, there is still a need for improved insulating materials for printed circuit elements, in particular for multilayer printed circuit elements or assemblies.

[0013] Correspondingly, it was a primary object of the present invention to provide a composition for making an insulating thermosetting resin, an insulating thermosetting resin thereof and an insulating thermoset polymer thereof, with particularly favourable properties when used as electrical insulation or as electrical insulation material in a printed circuit element and / or as a build-up film material in a printed circuit element. Said composition, thermosetting resin or thermoset polymer should show improved dielectric properties, in particular improved (low) material loss tangent (Df) and / or improved material relative permittivity (Dk) values. In addition, said thermosetting resin or thermoset polymer should preferably be characterised by a combination of properties that are advantageous for the desired purpose, comprising e.g. good mechanical and processing properties, good laminability, a high glass transition temperature (Tg), high peel strength and a curing temperature not exceeding and preferably below 200 °C. Further objects of the present invention were to provide a thermosetting resin and thermoset polymer with improved electrical and / or mechanical properties and a composition for making them, as well as a layer composite and a printed circuit element comprising such thermosetting resin or thermoset polymer. Additional objects of the present invention were directed to providing a method of making of a printed circuit element, and to provide a preimpregnated fiber article, comprising said composition or thermosetting resin.

[0014] It has now been found that the primary object and other objects of the present invention can be accomplished by the use of a composition for making an insulating thermosetting resin (preferably an electrically insulating thermosetting resin), comprising

[0015] C1) a curable component, comprising or consisting of: c1) a carbodiimide component, comprising or consisting of one or more than one open-chain carbodiimide compound and c2) a cyanate ester component, comprising or consisting of one or more than one cyanate ester compound, wherein the one or at least one of the more (or all of the more) cyanate ester compounds is (are) selected from the group consisting of cyanate ester compounds comprising two or more than two cyanate ester groups; and

[0016] C2) a catalyst component suitable for catalysing curing of the curable component, or of an insulating thermosetting resin (preferably an electrically insulating thermosetting resin) made from said composition (wherein preferably said insulating thermosetting resin or electrically insulating thermosetting resin comprises a - preferably pre-cured - reaction product of the curable parts of the composition for making an insulating thermosetting resin), or of an insulating thermoset polymer (preferably an electrically insulating thermoset polymer) of said insulating thermosetting resin (preferably of an insulating or electrically insulating thermoset polymer made from said insulating thermosetting resin), wherein the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 5 to 5 : 1 , the mass ratio between the total mass of the curable component C1) and the total mass of any other curable substances present in the composition (preferably including curable epoxy compounds), is > 10 : 1 ; and wherein the use is as electrical insulation or as electrical insulation material in a printed circuit element (preferably in a multilayer printed circuit element or assembly) and / or as a build-up film material in a printed circuit element (preferably in a multilayer printed circuit element or assembly).

[0017] The invention as well as preferred variants and preferred combinations of parameters, properties and elements thereof are defined in the appended claims. Preferred aspects, details, modifications and advantages of the present invention are also defined and explained in the following description and in the examples shown below.

[0018] If not stated otherwise, preferred embodiments, aspects or features of the present invention can be combined with other embodiments, aspects or features, especially with other preferred embodiments, aspects or features, irrespective of the categories to which the embodiments, aspects orfeatures relate. The combination of preferred embodiments, aspects or features with other preferred embodiments, aspects or features in each case again results in preferred embodiments, aspects or features. If not stated otherwise, the term “insulating” as used herein (e.g. in the context of an “insulating thermosetting resin” or of an “insulating thermoset polymer”) means “electrically insulating”.

[0019] It has now been found by the present inventors (and it is shown in the examples below), that an insulating thermosetting resin made from the composition for making an insulating thermosetting resin as defined above, or a thermoset polymer made from said insulating thermosetting resin, show beneficial dielectric properties, in particular a particularly low material loss tangent (Df) value and in many cases an improved material relative permittivity (Dk) value. In addition, an insulating thermosetting resin as described herein is characterised by a combination of properties that are advantageous for the desired purpose (as explained above and below), comprising in particular good mechanical and processing properties, good laminability, a high glass transition temperature (Tg), high peel strength and a curing temperature not exceeding and in most cases below 200 °C.

[0020] It has further been found that the insulating thermosetting resin made from the composition for making an insulating thermosetting resin (as described herein), may be used as electrical insulation or as electrical insulation material in a printed circuit element, in particular if the viscosity of said insulating thermosetting resin is adjusted accordingly. The person skilled in the art knows how to adjust the viscosity in a suitable manner, e.g. by adjusting the conditions of pre-curing said composition to result in a suitable thermosetting resin. The insulating thermosetting resin as described herein is oftentimes only used temporarily as electrical insulation or as a temporary electrical insulation material in a printed circuit element and is subsequently (further) cured for permanent use as electrical insulation or as permanent electrical insulation material in a printed circuit element.

[0021] As used herein and in accordance with the general understanding in the technical field, a “thermosetting resin” designates a monomer or a system of monomers (which are in the present case present in the composition for making an insulating thermosetting resin as described herein) that have been reacted (cured) to an intermediate-molecular mass state. This material (the thermosetting resin) is capable of further polymerization by reactive groups to a further or fully cured, high-molecular-mass state (i.e. to the “insulating thermoset polymer” in the present case). A “thermosetting resin” as described herein is usually present in the form of a soft solid or viscous liquid. A “thermosetting resin” as described herein (specifically as “insulating thermosetting resin”) may also be referred to as a “prepolymer”, a term which is generally known in the technical field. As used herein “pre-curing” or “pre-cured” means curing (at least) the curable component C1) of the composition for making an insulating thermosetting resin (and further curable parts which may be present in the composition) used according to the present invention, in the presence of a catalyst component C2) at a pre-curing temperature, preferably in the range of from > 70 °C to < 120 °C, more preferably in the range of from > 80 °C to < 120 °C, and for a pre-curing time period, preferably in the range of from > 1 min. to < 10 min., more preferably in the range of from > 2 min. to < 5 min., both sufficient for initiating a (pre- ) curing process, i.e. partially hardening but not fully curing said composition (see above), so that the resulting insulating thermosetting resin can later be cured at a curing temperature (which preferably is higher than the pre-curing temperature and preferably is in the range of from 120 °C to 200 °C, more preferably in the range of from 140 °C to 190 °C) and at a curing time period (which preferably takes longer time than the pre-curing time period and is preferably in the range of from 20 min. to 120 min., more preferably in the range of from 60 min. to 120 min.) to yield a (cured) insulating thermoset polymer. The best possible mechanical and / or electrical properties are achieved with an insulating thermoset resin, which is a (further) cured insulating thermosetting resin as described herein.

[0022] An insulating thermosetting resin for use according to the present invention as defined herein can preferably be made by curing or pre-curing a composition for making an insulating thermosetting resin for use according to the present invention as defined herein, at a suitable temperature and for a suitable time period, so that said insulating thermosetting resin comprises a (preferably pre-cured) reaction product of the curable parts of the composition for making an insulating thermosetting resin.

[0023] As used herein and in accordance with the general understanding in the technical field, a “thermoset polymer” is a polymer that is obtained by irreversibly hardening (curing) of a thermosetting resin (see above), preferably for a curing time period and preferably at a curing temperature (see above for applicable definitions thereof). Accordingly, an insulating thermoset polymer for use according to the present invention as defined herein can preferably be made by curing an insulating thermosetting resin for use according to the present invention as defined herein, at a suitable temperature and for a suitable time period, so that said insulating thermoset polymer comprises a (further or fully) cured reaction product of the insulating thermosetting resin.

[0024] In many cases, a skilled person can determine if or confirm that a (further) cured insulating thermosetting resin or insulating thermoset polymer as described herein has been obtained, by preparing an insulating thermosetting resin and subsequently further curing said insulating thermosetting resin for different amounts of time at a desired curing temperature, while measuring in each case the glass transition temperature (Tg) of the insulating thermoset polymer so received. Once the glass transition temperature of the insulating thermoset polymer does not increase further, it has reached its full crosslinked density (is “fully cured”), or a crosslinked density sufficient for the desired purpose. Or alternatively, the storage moduli of insulating thermoset polymers cured at different times and temperatures can be measured and the insulating thermoset polymer with highest storage modulus which does not further change has reached its full crosslinked density (is “fully cured”), or a crosslinked density sufficient for the desired purpose.

[0025] As used herein, an “open-chain carbodiimide” is a carbodiimide wherein preferably the carbodiimide molecule (or molecules, in case the carbodiimide comprises a mixture of different monomers, oligomers and / or polymers) has an open-chain structure and the main chain of the molecule or molecules does not form a cyclic structure (while substituents of the main chain of the open-chain carbodiimide molecule may carry or may comprise cyclic structures).

[0026] Preferred is a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as described above or below as being preferred), wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is (are) an open-chain carbodiimide compound of formula I wherein

[0027] R1and R2are each independently selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22, preferably 1 to 15, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an alkoxypolyoxyalkylene group, R3is a divalent residue formed by reaction of an organic diisocyanate compound OCN- R3-NCO with organic compounds carrying suitable groups reactive with the isocyanate groups of the organic diisocyanate compound;

[0028] R4is a divalent residue formed by reaction of an organic diol compound HO-R4-OH with organic compounds carrying one or more than one isocyanate groups (preferably more than one isocyanate groups) reactive with the hydroxy functional groups of the organic diol compound; wherein preferably the organic diol compound HO-R4-OH used for preparing the compound of formula I is selected from the group consisting of ethylene glycol, neopentylglycol, propylene glycol, 1 ,3-butanediol and 1 ,4-butanediol;

[0029] X1and X2are each independently selected from the group consisting of -N=C=N-, --OC(O)- N(H)-, -N(H)-C(O)-N(H)- and -N(R11)-C(O)-N(H)-, wherein R11is selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22, preferably 1 to 15 and more preferably 1 to 10, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18, preferably 6 to 12, carbon atoms and an aralkyl group having 7 to 20 carbon atoms, m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 39, preferably of from 0 to 20, more preferably of from 0 to 10 and even more preferably from 0 to 5.

[0030] It has been found in own experiments that an insulating thermosetting resin as defined above, or an insulating thermoset polymer made from it, shows beneficial dielectric properties, in particular a beneficially low material loss tangent (Df) value and a low temperature dependency of (low) material loss tangent (Df) values, as well as other properties favourable for the intended purpose.

[0031] The carbodiimide compound of formula I and / or the carbodiimide compound of formula (la) (see below) and methods for their manufacture are generally known in the art, e.g. from documents EP 628 541 ; EP0850985 A1 ; US 5,498,747; US 2016 / 0096951 A1 ; US 2017 / 0334839 A1 and / or W02021 / 085050 A1 , or said compounds can be made by methods generally known in the art. A carbodiimide compound of formula I and / or a carbodiimide compound of formula (la) and methods for their manufacture are furthermore described in documents WO 2017 / 194360 A1 and WO 2019 / 185409 A1 , and in the literature cited in said documents.

[0032] In the carbodiimide component c1) of the curable component C1) of the composition for making an insulating thermosetting resin (or the resulting insulating thermosetting resin or insulating thermoset polymer), as used according to the present invention, the one or more than one open-chain carbodiimide compounds of formula I may comprise one single compound (e.g. a single, uniform compound, a single, uniform oligomer or a single, uniform oligomer polymer) of formula I, or it may comprise a mixture of two or more compounds (e.g. two or more single, uniform compounds, two or more single, uniform oligomers ortwo or more single, uniform pre-polymers) of formula I.

[0033] More in particular, there is preferred a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula la wherein

[0034] R1ais a straight-chain or branched alkyl group having 1 to 10, preferably 2 to 10, and more preferably 2 to 8, carbon atoms; R3and R4have the meanings as defined above (orthe meanings as defined above or below as being preferred), m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 10, preferably of from 0 to 5.

[0035] In a preferred variant, the curable component C1) of the composition for making an insulating thermosetting resin (or the resulting insulating thermosetting resin or insulating thermoset polymer), as used according to the present invention, the one or more than one open-chain carbodiimide compounds of formula (la) may comprise one single compound (e.g. a single, uniform compound, a single, uniform oligomer or a single, uniform oligomer polymer) of formula (la), or it may comprise a mixture of two or more compounds (e.g. two or more single, uniform compounds, two or more single, uniform oligomers or two or more single, uniform pre-polymers) of formula (la).

[0036] Preferred is further a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula I as defined above (or an open-chain carbodiimide compound of formula I as defined above as being preferred), or of formula la as defined above (or an open-chain carbodiimide compound of formula la as defined above as being preferred), wherein in each case the divalent residue R3is selected from the group consisting of a straight-chain or branched alkylene group having 1 to 22, preferably 1 to 15, carbon atoms; a straight-chain or branched alkylene group having 1 to 6, preferably 1 to 4, carbon atoms, where the alkylene group is substituted and / or interrupted by 1 or 2 cycloalkyl or cycloalkylene groups, each having 5 to 12, preferably 5 to 6 carbon atoms; a straight-chain or branched alkylene group having 1 to 6, preferably 1 to 4, carbon atoms, where the alkylene group is substituted and / or interrupted by 1 or 2 aryl or arylene groups, each having 6 to 18, preferably 6 to 12 carbon atoms; a cycloalkylene group having 5 to 12, preferably 5 to 6, carbon atoms; and an arylen group having 6 to 18, preferably 6 to 12, carbon atoms, or selected from the divalent residues which can be obtained from diisocyanate compounds OCN-R3-NCO used in the reaction for producing the carbodiimide compound of formula I or of formula la, where the diisocyanate compound OCN-R3-NCO is selected from the group consisting of hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1 ,3-bis (isocyanatomethyl) cyclohexane, 1 ,4-bis (isocyanatomethyl) cyclohexane, 2,2-bis (4-isocyanatocyclo- hexyl) propane, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, di- cyclohexylmethane-3,3'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocya- nate, diphenylmethane diisocyanate, 2,4,6-triisopropylbenzene-1 ,3-diyl diisocyanate, m-xylylene diisocyanate, 1 ,3-bis (2-isocyanato-2-propyl) benzene and 1 ,4-bis (2-isocy- anato-2-propyl) benzene, preferably selected from the group consisting of isophorone diisocyanate, dicyclohex- ylmethane-4,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, 1 ,3-bis-(2-isocy- anato-2-propyl) benzene and 1 ,4-bis (2-isocyanato-2-propyl) benzene, and more preferably selected from the group consisting of dicyclohexylmethane-4,4'- diisocyanate and dicyclohexylmethane-3,3'-diisocyanate; or selected from the group consisting of a divalent residue of formula II a divalent residue of formula III a divalent residue of formula IV and a divalent residue of formula V wherein the character “#” denotes in each case the covalent bonding connection to the carbodiimide compound of formula I or of formula la, respectively.

[0037] Certain preferred open-chain carboodiimide compounds of formula I or of formula la for use according to the present invention are carbodiimides known under the tradename “Sta- baxol” by Lanxess AG, in particular “Stabaxol® P 100” (carbodiimide based on 3,5-triiso- propyl-phenylen-2,4-diisocyanate), or carbodiimides known under the tradename “Elastostab” by BASF SE, in particular a carbodiimide based on dicyclohexylmethane-4,4'-diiso- cyanate (also known as 4,4'-diisocyanato dicyclohexylmethane or“Hi2MDI” and sometimes referred to as “Elastostab® H05”) and “Elastostab® H01 ” (carbodiimide based on 3-bis(1 - isocyanato-1-methylethyl)-benzene).

[0038] Preferred is furthermore a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is (are) a difunctional cyanate ester compound of formula VI

[0039] (VI), wherein

[0040] R11through R18are independently selected from the group consisting of hydrogen, linear C1-10 alkyl, halogenated linear C1-10 alkyl, branched C4-10 alkyl, halogenated branched C4-10 alkyl, C3-8 cycloalkyl, halogenated C3-8 cycloalkyl, linear C2-C10 alkenyl, branched C3-C10 alkenyl, C1-10 alkoxy, halogen, phenyl and phenoxy; wherein at least one of R11to R18is selected from the group consisting of linear C2- C10 alkenyl and branched C3-C10 alkenyl;

[0041] Z1indicates a direct bond or a divalent moiety selected from the group consisting of -O-, -S-, -S(=O)-, -S(=O)2-, -CH2-, -CH(CH3)-, -C(CH3)2-,-CH(CF3)-, -C(CF3)2-, -C(=O)-, -C(=CH2)-, -C(=CCl2)-, -Si(CHs)2-, linear C1-10 alkanediyl, branched C4- 10-alkanediyl, Cs-s-cycloalkanediyI, 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4-phenylene, -N(R13)- wherein R13is selected from the group consisting of hydrogen, linear C1-10 alkyl, halogenated linear C1-10 alkyl, branched C4-10 alkyl, halogenated branched C4- 10 alkyl, C3-8 cycloalkyl, phenyl and phenoxy, and moieties of formulae wherein X is independently selected from hydrogen and halogen; and oligomers, pre-polymers, polymers or mixtures thereof; wherein preferably the cyanate ester compound (or compounds) of cyanate ester component c2) comprises or is a mixture of one or more compounds of formula VI and one or more compounds selected from the group consisting of: i) a polyfunctional cyanate ester compound of formula VII wherein n is an integer in the range of from 1 to 20; and

[0042] R20and R21are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C4-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; ii) a polyfunctional cyanate ester compound of formula VIII-1

[0043] (VIII-1) wherein n is an integer in the range of from 1 to 20; and

[0044] R30, R31, R32and R33are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; iii) a polyfunctional cyanate ester compound of formula VIII-2

[0045] (VIII-2) wherein n is an integer in the range of from 1 to 20; and

[0046] R34, R35and R36are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; iv) a polyfunctional cyanate ester compound of formula VIII-3

[0047]

[0048] (VI 11-3) wherein n is an integer in the range of from 1 to 20; and

[0049] R37is selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; v) a polyfunctional cyanate ester compound of formula VIII-4

[0050] (VIII-4) wherein n is an integer in the range of from 1 to 20; and oligomers, pre-polymers, polymers or mixtures thereof. In the cyanate ester component of the curable component C1) of the composition for making an insulating thermosetting resin as used according to the present invention (or the resulting insulating thermosetting resin or insulating thermoset polymer), the one or at least one of the more cyanate ester compounds comprising two or more than two cyanate ester groups of formulae (VI), (VI I), (VII 1-1 ), (VIII-2), (VIII-3) and (VIII-4) may comprise one single cyanate ester compound (i.e. a single, uniform compound, a single, uniform oligomer or a single, uniform pre-polymer) of each kind of said formulae, or they may comprise a mixture of two or more cyanate ester compounds (i.e. two or more single, uniform compounds, two or more single, uniform oligomers or two or more single, uniform pre-polymers) of each kind of said formulae, and / or the cyanate ester component of the curable component C1) (or the resulting insulating thermosetting resin or insulating thermoset polymer) may comprise a mixture of two or more than two cyanate ester compounds comprising two or more than two cyanate ester groups, which may be selected in each case from cyanate ester compounds of different formulae (VI), (VII), (VIII-1), (VIII-2), (VIII-3) and / or (VIII-4).

[0051] The difunctional cyanate ester compound of formula VI, the polyfunctional cyanate ester compound of formula VII, the polyfunctional cyanate ester compound of formula VIII-1 , the polyfunctional cyanate ester compound of formula VIII-2, the polyfunctional cyanate ester compound of formula VIII-3 and the polyfunctional cyanate ester compound of formula VIII- 4 as well as methods for their manufacture are generally known in the art, e.g. from documents EP 0 803 538 A2; EP 3 260 501 A1 ; US 2009 / 0215943 A1 ; WO 2015 / 065501 A1 , WO 2021 / 260124 A1 , or can be made by methods generally known in the art.

[0052] Certain preferred cyanate ester compounds for use according to the present invention are cyanate ester compounds known under the tradename “Primaset” by Arxada Ltd. of Switzerland, in particular “Primaset® BADCy” (4,4'-isopropylidene diphenyl dicyanate), “Primaset® BA-230 S” (preferably cyanic acid (1-methylethylidene)di-4,1 -phenylene ester homopolymer, CAS RN 25722-66-1), “Primaset® LECy” (4,4'-ethylidene diphenyl dicyanate), “Primaset® PT-30 S” (an oligo(3-methylene-1 ,5-phenylcyanate), “Primaset® ULL-950 S”, and their mixtures. More in particular, there is preferred a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX,

[0053] wherein: k is 0 or 1 ,

[0054] I is 0 or an integer in the range of from 1 to 10, R6and R7are the same or different and each represents a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, an alkyl halide group having from 1 to 20 carbon atoms, or halogen;

[0055] R8represents a chemical group selected from the group consisting of the following members: -CH2-, -CH(CH3)-, -C(CH3)2-, -O-, -S-, -S(O)-, -(CH3)2C-benzyl-C(CH3)2- and dicyclopentadienyl,

[0056] R9represents a chemical group selected from the group consisting of a divalent residue of formula X wherein k, R6, R7and R8have the above meanings and the character “#” denotes in each case the covalent bonding connection to the compound of formula IX, and a divalent residue of formula XI wherein the character “#” denotes in each case the covalent bonding connection to the compound of formula IX, or a pre-polymer thereof; and a compound or mixture of compounds of formula XII

[0057] Tr-[W-(Z)f / (H)l-f-W|r-1-[W-(Z)f / (H)l.f-(OCN)f / (R)l.f]r+2 (XII), wherein

[0058] T is a 1 ,3,5-substituted-triazine moiety C3N3;

[0059] W is an oxygen atom and is a linking atom between triazine and either compo- nent A or component B;

[0060] Z is component A;

[0061] H is component B;

[0062] OCN is a cyanate ester end group of component A;

[0063] R is a OH reactive end group of component B; r is an integer greater than or equal to 1 ; and f is a mol fraction of component A; wherein said compound or mixture of compounds is formed by chemical attachment of: a. at least one cyanate ester component A; b. at least one reactive intermediate component B, said component B being capable of copolymerization with said component A, said component B being a thermoplastic selected from the group consisting of (i) hydrogenated hydroxylated polybutadiene and (ii) polymethylphenylsiloxane containing between 3- 9 % (preferably between 3-9 mol-%) OH functional groups.

[0064] There is also preferred a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX as defined above; a compound or mixture of compounds of formula XII as defined above; 4,4'- isopropylidene diphenyl dicyanate; cyanic acid (1-methylethylidene)di-4,1 -phenylene ester homopolymer, (CAS RN 25722-66-1); 4,4'-ethylidene diphenyl dicyanate; oligo(3-meth- ylene-1 ,5-phenylcyanate) and mixtures thereof; preferably wherein the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound or mixture of compounds of formula XII as defined above; 4,4'-isoprop- ylidene diphenyl dicyanate; cyanic acid (1-methylethylidene)di-4,1-phenylene ester homopolymer, (CAS RN 25722-66-1); 4,4'-ethylidene diphenyl dicyanate; oligo(3-methylene-1 ,5- phenylcyanate) and mixtures thereof.

[0065] In the cyanate ester component of the curable component C1) of the composition for making an insulating thermosetting resin as used in the above-specified preferred variant according to the present invention (or the resulting insulating thermosetting resin or insulating thermoset polymer), the one or at least one of the more cyanate ester compounds comprising two or more than two cyanate ester groups of formulae IX and XII may comprise one single cyanate ester compound (i.e. a single, uniform compound, a single, uniform oligomer or a single, uniform pre-polymer) of each kind of said formulae, or they may comprise a mixture of two or more cyanate ester compounds (i.e. two or more single, uniform compounds, two or more single, uniform oligomers or two or more single, uniform prepolymers) of each kind of said formulae, and / orthe cyanate ester component ofthe curable component C1) (or the resulting insulating thermosetting resin or insulating thermoset polymer) may comprise a mixture of two or more than two cyanate ester compounds comprising two or more than two cyanate ester groups, which may be selected in each case from cyanate ester compounds of different formulae (IX) and / or (XII).

[0066] A preferred compound of formula IX wherein R9represents a divalent residue of formula IX, is - for the purpose of the present invention - the compound of formula (Xia):

[0067] The compound of formula XII, as well as preferred meanings of the variables defined therein (including as preferred for the purpose of the present invention) and methods for making it, are e.g. disclosed in document WO 2015 / 065501 A1 or in document EP 3 066 148 B1 , respectively. One preferred representative of a compound of formula XII for the purpose of the present invention is the commercially available cyanate ester compound “Primaset® ULL-950 S”.

[0068] There is also preferred a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the composition for making an insulating thermosetting resin, comprises

[0069] C1) a curable component, consisting of: c1) in a total amount in the range of from 5 to 20 mass-%, relative to the total mass of said composition, a carbodiimide component, consisting of one or more than one open-chain carbodiimide compound, wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula I wherein

[0070] R1and R2are each independently selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22 preferably 1 to 15, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14, carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an alkoxypolyoxyalkylene group,

[0071] R3is a divalent residue selected from the group consisting of a divalent residue of formula II a divalent residue of formula III, a divalent residue of formula IV and a divalent residue of formula V wherein the character “#” denotes in each case the covalent bonding connection to the carbodiimide compound of formula I;

[0072] R4is a divalent residue formed by reaction of an organic diol compound HO-R4-OH with organic compounds carrying one or more than one isocyanate groups reactive with the hydroxy functional groups of the organic diol compound; wherein preferably the organic diol compound HO-R4-OH used for preparing the compound of formula I is selected from the group consisting of ethylene glycol, neopentylglycol, propylene glycol, 1 ,3-butanediol and 1 ,4-butanediol;

[0073] X1and X2are each independently selected from the group consisting of - N=C=N-, -OC(O)-N(H)-, -N(H)-C(O)-N(H)- and -N(R11)-C(O)-N(H)-, wherein R11is selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22, preferably 1 to 15 and more preferably 1 to 10, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18, preferably 6 to 12, carbon atoms and an aralkyl group having 7 to 20 carbon atoms, m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 39, preferably of from 0 to 20, more preferably of from 0 to 10 and even more preferably from 0 to 5; and c2) a cyanate ester component, consisting of one or more than one cyanate ester compound, wherein the one or at least one of the more cyanate ester compounds is selected from the group consisting of cyanate ester compounds comprising two or more than two cyanate ester groups, wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX as defined above, a compound or mixture of compounds of formula XII as defined above;

[0074] 4,4'-isopropylidene diphenyl dicyanate; cyanic acid (1-methylethylidene)di-4,1-phenylene ester homopolymer, (CAS RN 25722-66-1);

[0075] 4,4'-ethylidene diphenyl dicyanate; oligo(3-methylene-1 ,5-phenylcyanate) mixtures thereof.

[0076] C2) a catalyst component suitable for catalysing curing of the curable component, wherein the catalyst component C2) is selected from the group consisting of catalytically active organic, nitrogen-containing compounds, catalytically active substances comprising organic, nitrogen-containing compounds and mixtures thereof, wherein the catalyst component C2) is selected from the group consisting of: imidazoles; tetraalkyl ammonium halides; bicyclic amino compounds; complexes comprising a Zn2+cation and one or more organic, nitrogen-contain- ing compounds, and mixtures thereof;

[0077] C3) a particulate inorganic filler, wherein the particulate inorganic filler is present in a total amount in the range of from 25 mass-% to 85 mass-%, relative to the total mass of said composition; and

[0078] C5) an organic solvent; or of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, wherein the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 5 to 5 : 1 , the mass ratio between the total mass of the curable component C1) and the total mass of epoxy compounds present in the composition is > 10 : 1 .

[0079] Under a further aspect is preferred a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as described above or below as being preferred), wherein the catalyst component C2) is selected from the group consisting of catalytically active organic, nitrogen-containing compounds, catalytically active substances comprising organic, nitrogen-containing compounds and mixtures thereof, wherein preferably the catalyst component C2) is selected from the group consisting of: imidazoles, preferably selected from the group consisting of 2-methylimidazole, 2- ethyl-4-methylimidazole, 2-ethyl-1 -methylimidazole, 2-phenylimidazole, 1-cyanoethyl- 2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxy- methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4,5-triphenylimidaz- ole, 4-methyl-2-phenyl-1 / - / -imidazole, 2-methyl-4-phenyl-1 / - / -imidazole and mixtures thereof; more preferably selected from the group consisting of 2-ethyl-4-methylimidaz- ole, 2-ethyl-1 -methylimidazole and mixtures thereof; tetraalkyl ammonium halides, preferably selected from the group consisting of tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide and mixtures thereof; bicyclic amino compounds, preferably selected from the group consisting of 1 ,8-diaza- bicyclo[5.4.0]undec-7-ene, 1 ,4-diazabicyclo[2.2.2]octan and mixtures thereof; complexes comprising a divalent metal cation, preferably a Zn2+-ion, and one or more organic, nitrogen-containing compounds, preferably selected from the group consisting of a complex comprising ZnCb and a tetraalkyl ammonium halide, preferably tetrabutyl ammonium bromide; and ZIF-8, and mixtures thereof, wherein more preferably the catalyst component is selected from the group consisting of bicyclic amino compounds, preferably selected from the group consisting of 1 ,8-di- azabicyclo[5.4.0]undec-7-ene, 1 ,4-diazabicyclo[2.2.2]octan and mixtures thereof; imidazoles selected from the group consisting of 2-ethyl-4-methylimidazole, 2-ethyl-1 - methylimidazole and mixtures thereof; and complexes comprising a divalent metal cation, preferably a Zn2+-ion, and one or more organic, nitrogen-containing compounds, preferably selected from the group consisting of a complex comprising ZnCb and a tetraalkyl ammonium halide, preferably tert. -butyl ammonium bromide; and ZIF-8.

[0080] “ZIF-8” is a metal organic framework (MOF) made by zinc ions coordinated by four imid- azolate rings (a “zeolitic imidazolate framework”) in the same way as Si and Al atoms are covalently joined by bridging oxygens in zeolites. ZIF-8 is known per se in the art, as well as methods for manufacturing it (cf. e.g. M. Bergaoui et al. in “Journal of Natural Gas Science and Engineering, 96 (2021) 104289 / https: / / doi.orc ' ' 1289).

[0081] It has been found in own experiments that the use of the catalyst components C2), in particular the use of the preferred catalyst components C2) as defined here above, results in insulating thermosetting resins (films) which have sufficient pot life to be coated onto PET foils at room temperature and stored at temperatures below -10 C. When these films are then laminated on copper substrates, they show good laminability and adhesion to copper and can usually be fully cured or sufficiently cured for the intended purpose to insulating thermoset polymers below a curing temperature of 200 °C in less than 2 hours, where said insulating thermoset polymers achieve good mechanical integrity as well as low dielctric losses when cured below 200 °C.

[0082] Preferred is furthermore a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein in the curable component C1) the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 3 to 3 : 1 , preferably of from 1 : 2.5 to 2.5 : 1 and more preferably of from 1 : 2 to 2 : 1 ; and / or the mass ratio between the total mass of the curable component C1) and the total mass of any other curable substances present in the composition, preferably the mass ratio between the total mass of the curable component C1) and the total mass of epoxy compounds present in the composition, is > 10 : 1 , preferably > 20 : 1 , and more preferably > 25 : 1 . and / or the one, or at least one of the more, or (preferably) all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is (are) an open-chain carbodiimide compound of formula la as defined here above; and the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of ac compound of formula IX and a compound or mixture of compounds of formula XII as defined above, preferably is selected from a compound or mixture of compounds of formula XII as defined above.

[0083] It has been found in own experiments that an insulating thermosetting resin or insulating thermoset polymer made from the preferred curable components as defined here above shows the best combination of beneficial dielectric properties (in particular a particularly low material loss tangent (Df) value and a particularly good material relative permittivity (Dk) value) as well as beneficial mechanical and processing properties, good laminability, a high glass transition temperature (Tg), high peel strength and a suitable curing temperature not exceeding and in most cases below 200 °C. Preferred is furthermore a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or insulating thermoset polymer according to the invention as described above or below as being preferred), wherein the carbodiimide component c1) is present in the composition for making an insulating thermosetting resin in a total amount in the range of from 5 to 20 mass-%, preferably of from 5 to 15 mass-%, relative to the total mass of said composition; and / or the cyanate ester component c2) is present in the composition for making an insulating thermosetting resin in a total amount in the range of from 5 to 25 mass-%, preferably of from 5 to 20 mass-%, relative to the total mass of said composition.

[0084] Moreover, a use of a composition, insulating thermosetting resin or thermoset polymer according to the present invention as defined herein (or a use of a composition, insulating thermosetting resin or thermoset polymer according to the invention as described above or below as being preferred) is preferred, wherein the composition for making an insulating thermosetting resin further comprises:

[0085] C3) a particulate inorganic filler, preferably selected from the group consisting of silica, silane surface-modified silica, boehmite, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, aluminium oxide, titanium oxide, zinc oxide, zinc borate, zinc stannate, magnesium oxide, zirconium oxide, boron nitride, silicon nitride, aluminium nitride, barium sulfate and mixtures thereof; wherein preferably the particulate inorganic filler comprises silica and / or silane surface-modified silica or the particulate inorganic filler is selected from the group consisting of silica and silane surface-modified silica; wherein preferably the particulate inorganic filler is present in a total amount in the range of from 25 mass-% to 85 mass-%, more preferably of from 30 mass-% to 80 mass-% and even more preferably of from 60 mass-% to 75 mass-%, relative to the total mass of said composition; and / or C4) a particulate organic filler, preferably selected from the group consisting of polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen, silicone resin powder, silicone rubber powder, silicone composite powder, styrene-based powder, butadiene-based powder, acryl- based powder; core shell-type rubber powders and mixtures thereof, wherein more preferably the particulate organic filler comprises polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen and mixtures thereof, or the particulate organic filler is selected from the group consisting of polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen and mixtures thereof; and / or

[0086] C5) an organic solvent, preferably selected from the group consisting of acetone, methyl ethyl ketone, cyclohexanone, methyl cellosolve, toluene, xylene, N,N-dimethyl formamide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and mixtures thereof, wherein more preferably the organic solvent comprises or is methyl ethyl ketone; wherein preferably the organic solvent is present in a total amount in the range of from 4 mass-% to 25 mass-%, more preferably of from 5 mass-% to 20 mass-%, relative to the total mass of said composition; and / or

[0087] C6) one or more members from the group consisting of impact modifiers, flow additives, flame retardants, coloring agents, particle dispersion aids and surfactants; or where preferably the insulating thermosetting resin or the thermoset polymer made therefrom comprises a reaction product of the curable parts of the composition for making an insulating thermosetting resin, where said composition comprises (or comprised, as applicable) said further components C3), C4), C5) and / or C6). Where the particulate inorganic filler C3) comprises silica and / or silane surface-modified silica or the particulate inorganic filler is selected from the group consisting of silica and silane surface-modified silica, said silica or silane surface-modified silica preferably has a median particle size distribution D50 in the range of from 0.1 pm to 0.5 pm, measured by laser diffraction particle size analyzer, more preferably between 0.15 to 0.5 urn nd the size of the largest particle preferably not exceeding 1.0 pm.

[0088] Also preferred is a use according to the present invention of an insulating thermosetting resin (or the use of an insulating thermosetting resin according to the present invention as described above or below as being preferred), wherein said insulating thermosetting resin is obtained from a composition for making an insulating thermosetting resin as defined herein, or from a composition for making an insulating thermosetting resin as defined herein as being preferred, by a curing process (or pre-curing process, respectively) comprising thermal curing, preferably at a temperature in the range of from 120 °C to 210 °C, more preferably of from 140 °C to 200 °C, even more preferably in the range of from 160 °C to 185 °C, and preferably for a pre-curing time period, preferably in the range of from 15 min. to 45 min., more preferably in the range of from 20 min. to 35 min; and / or is in the form of a web or film.

[0089] The present invention also relates to a composition for making an electrically insulating thermosetting resin, an electrically insulating thermosetting resin made from said composition, or an electrically insulating thermoset polymer of said thermosetting resin as defined herein (or a composition for making an electrically insulating thermosetting resin, electrically insulating thermosetting resin made from said composition, or electrically insulating thermoset polymer of said thermosetting resin as defined herein as being preferred), wherein preferably the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula la as defined herein (or an open-chain carbodiimide compound of formula la as defined herein as being preferred) and the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX and a compound or mixture of compounds of formula XII as defined herein (or as defined herein as being preferred), preferably the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound or mixture of compounds of formula XII as defined herein (or as defined herein as being preferred).

[0090] Generally, all aspects of the present invention discussed herein in the context of the inventive use of a composition for making an insulating thermosetting resin, of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, apply mutatis mutandis to the composition for making an insulating thermosetting resin, the thermosetting resin made from said composition and the thermoset polymer of said thermosetting resin (all) according to the present invention as defined herein, and vice versa

[0091] It has been found in own experiments that a thermosetting resin according to the present invention as defined here above is particularly suited for use as a build-up film in a multilayer printed circuit element, due to its particularly low material loss tangent, where said particularly low material loss tangent has only a low temperature dependence.

[0092] The present invention further relates to a layer composite, comprising at least the following layers:

[0093] L1) a carrier layer, comprising or consisting of an organic polymer, preferably comprising or consisting of polyethylene terephthalate,

[0094] L2) a layer comprising or consisting of a composition for making an electrically insulating thermosetting resin; an electrically insulating thermosetting resin or an electrically insulating thermoset polymer, all as defined above (or as defined above as being preferred), and L3) a covering layer, disposed on the layer L2), preferably comprising or consisting of an organic polymer, more preferably comprising or consisting of oriented polypropylene, wherein preferably the layer L2) is arranged between, and preferably in contact with, the two layers L1) and L3); and / or is disposed on and in contact with layer L1).

[0095] Generally, all aspects of the present invention discussed herein in the context of the inventive use of a composition for making an insulating thermosetting resin, of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, and / or in the context of the inventive composition for making an insulating thermosetting resin, the thermosetting resin made from said composition and the thermoset polymer of said thermosetting resin, apply mutatis mutandis to the layer composite according to the present invention as defined herein, and vice versa.

[0096] A layer composite according to the present invention is a valuable tool or transfer substrate for transferring in particular a layer L2), comprising or consisting of an insulating thermosetting resin, to a surface of a first conductive pattern of a precursor of a printed circuit element (as is further referred to below).

[0097] The present invention additionally relates to a printed circuit element, preferably a multilayer printed circuit assembly, comprising: at least one conductor layer and at least one electrically insulating layer comprising a composition for making an electrically insulating thermosetting resin; an electrically insulating thermosetting resin or an electrically insulating thermoset polymer, all as defined above (or as defined above as being preferred), where the at least one electrically insulating layer is disposed on and preferably in contact with a surface of the at least one conductor layer. Generally, all aspects of the present invention discussed herein in the context of the inventive use of a composition for making an insulating thermosetting resin, of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, and / or in the context of the inventive composition for making an insulating thermosetting resin, the thermosetting resin made from said composition and the thermoset polymer of said thermosetting resin and / or in the context of the layer composite according to the present invention apply mutatis mutandis to the printed circuit element according to the present invention as defined herein, and vice versa.

[0098] Even further, the present invention also relates to a method of making a printed circuit element, preferably a multilayer printed circuit assembly, comprising at least the following steps:

[0099] M1) providing or preparing an electrically insulating thermosetting resin made from a respective composition (for making an electrically insulating thermosetting resin) as defined above (or as defined above as being preferred);

[0100] M2) providing or preparing a precursor of a printed circuit element having on at least one of its surfaces a first conductive pattern, preferably comprising or consisting of copper metal;

[0101] M3) applying the electrically insulating thermosetting resin from step M1) to the surface of at least a part of the first conductive pattern of the precursor of the printed circuit element from step M2), and optionally further pre-curing said electrically insulating thermosetting resin, to receive a layer of an (optionally further pre-cured) electrically insulating thermosetting resin, disposed on at least a part of said first conductive pattern;

[0102] M4) arranging one or more connecting holes at defined positions of said layer of an (optionally further pre-cured) electrically insulating thermosetting resin (as received in step M3);

[0103] M5) applying to or disposing on said layer of an (optionally further pre-cured) electrically insulating thermosetting resin received in step M3), including the connecting holes, in one or more steps, a second conductive pattern, preferably comprising or consisting of copper metal; where the second conductive pattern is separated from the first conductive pattern by the (optionally further pre-cured) electrically insulating thermosetting resin received, including the connecting holes, and is in contact with the first conductive pattern at least at some of the one or more connecting holes,

[0104] M6) Further curing the (optionally further pre-cured) electrically insulating thermosetting resin separating the first and second conductive patterns (but allowing contact of the first and second conductive patterns via the connecting holes), preferably at a temperature in the range of from 100 °C to 200 °C, preferably in the range of from 120 °C to 180 °C, preferably to result in a printed circuit element comprising a layer of an electrically insulating thermoset polymer.

[0105] Generally, all aspects of the present invention discussed herein in the context of the inventive use of a composition for making an insulating thermosetting resin, of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, and / or in the context of the inventive composition for making an insulating thermosetting resin, the thermosetting resin made from said composition and the thermoset polymer of said thermosetting resin and / or in the context of the layer composite according to the present invention and / or in the context of printed circuit element according to the present invention apply mutatis mutandis to the method of making a printed circuit element according to the present invention as defined herein, and vice versa.

[0106] The present invention then also relates to a pre-impregnated fiber article (also known as “prepreg”), comprising a fiber substrate impregnated with an electrically insulating thermosetting resin according to the present invention as defined herein (or with an electrically insulating thermosetting resin according to the present invention as defined herein as being preferred).

[0107] Generally, all aspects of the present invention discussed herein in the context of the inventive use of a composition for making an insulating thermosetting resin, of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, and / or in the context of the inventive composition for making an insulating thermosetting resin, the thermosetting resin made from said composition and the thermoset polymer of said thermosetting resin and / or in the context of the layer composite according to the present invention and / or in the context of printed circuit element according to the present invention and / or in the context of the method of making a printed circuit element according to the present invention also apply mutatis mutandis to the pre-impregnated fiber article according to the present invention as defined herein, and vice versa. Examples:

[0108] The following examples are meant to further explain and illustrate the present invention, without limiting its scope.

[0109] Table 1 : Materials used Example 1 : Compositions for making an insulating thermosetting resin

[0110] Compositions for making an insulating thermosetting resin were prepared by mixing the components as shown in tables 2a-b below.

[0111] Table 2a: Compositions for making insulating thermosetting resins for use according to the present invention (part 1)

[0112] * mass percentage values given for CDI cpd. (1) refer to actual mass of solid CDI cpd. (1), not to solution (as described in table 1 above) used.

[0113] Table 2b: Compositions for making insulating thermosetting resins for use according to the present invention (part 2) see note to table 2a above 2: General procedure for preparing insulating thermosetting resins for use according to the present invention

[0114] Insulating thermosetting resins were prepared from the compositions for making insulating thermosetting resins as shown in tables 2a and 2b above (CTR-1 to CTR-12) by the general procedure provided here below, and named ITR-1 to ITR-12, respectively.

[0115] The carbodimide compounds (according to tables 2a and 2b above) were dissolved in methyl ethyl ketone to make a 50% (wt. / wt.) solution. Solutions of cyanate ester compounds were used as received from the supplier (see tables 1 , 2a and 2b). The silica particles were used as slurries as received (see tables 1 , 2a and 2b). The required amount of cyanate ester compound and carbodiimide compound solution was homogenized in a Hauschild Speed Mixer® DAC800 for 10 min. at a mixing speed of 1950 rpm. The silica particles were then added to this mixture and the mixture was further stirred followed by a treatment in an ultrasound bath for 10 min. To this homogenized solution, the catalyst (as specified in tables 1 , 2a and 2b) was added and the resulting mixture stirred again in a speed mixer for 1 min. for use accord- ing to the present invention

[0116] The insulating thermosetting resins ITR-1 to ITR-12 as prepared according to example 2 above were filtered using a depth filter and their volumes were subsequently reduced to 85 % of their starting volumes. The resulting resins were applied on to a PET substrate with a doctor blade (height of blade: 150 pm) and cured at 200 °C for 2 hours to result in insulating thermoset polymers named ITP-1 to ITP-12, respectively. thermoset

[0117] The glass transition temperature (Tg) is a measure of the thermal stability and stiffness of a sample and also gives an indication of the limits of operating temperatures that the insulating thermoset polymers (films) can be used in a device.

[0118] “IPC Test Methods” (“IPC-TM” in the following) refer to standard test methods as issued by the global trade association founded in 1957 as the “Institute for Printed Circuits” and are commonly known in the technical field. Glass transition temperatures Tgof insulating thermoset polymers as prepared according to example 3 above were determined by dynamic mechanical analysis (DMA) and are reported in table 3 below. The glass transition temperature was measured by the DMA method following IPC-TM 650 2.4.24.3 test method. A RSA G2 solids analyzer from TA Instrument was used. thermoset

[0119] Material loss tangent values Df of insulating thermoset polymers as prepared according to example 3 above were determined at room temperature and at 90 °C by split post dielectric resonator. A network analyzer keysight E5071 C (300kHz - 20 GHz) was used for this test. The values (test results) are reported in table 3 below. The Df values were all measured at 10 GHz. thermoset

[0120] Elastic moduli of insulating thermoset polymers as prepared according to example 3 above were determined by the IPC-TM 650 2.4.18.3 test method. Testing was performed on a Zwick Z50 universal testing machine. A load cell of 20 N was used. The values (test results) are reported in table 3 below.

[0121] The elongation at break is a measure of the flexibility of the insulating thermoset polymers and consequently a measure of theirtoughness. The higherthe elongation at break values are, the less brittle is the insulating thermoset polymer and therefore has more mechanical integrity when used in an integrated circuit (IC) or a printed circuit board (PCB).

[0122] Elongation at break of insulating thermoset polymers as prepared according to example 3 above were determined by IPC-TM 650 2.4.18.3 test method. Testing was performed on a Zwick Z50 universal testing machine. A load cell of 20 N was used. The values (test results) are reported in table 3 below. Table 3: Technical parameters determined for insulating thermoset polymers for use according to the present invention

[0123] The data summarized in table 3 above show that the insulating thermoset polymers ob- tained according to the methods provided herein have high toughness and flexibility. Moreover, said insulating thermoset polymers have high Tg-values and show particularly low dielectric losses of < 0.003 at room temperature, and less than 0.005 at elevated temperatures of 90 °C.

[0124] Due to their high Tg-values, the insulating thermosetting resins or insulating thermoset polymers (films) show excellent thermal and dimensional stability at elevated temperatures

[0125] (i.e. temperatures reached at operating conditions of a device). In addition, the elastic moduli of the insulating thermoset polymers obtained according to the methods provided herein are much higher than elastic moduli of many build-up films known from the prior art.

[0126] Thus, the insulating thermoset polymers made according to the present invention show a favourable combination of good lamination properties, excellent adhesion to copper, high toughness and flexibility, while maintaining extremely low Df values.

Claims

Claims:1 . Use of a composition for making an insulating thermosetting resin, comprisingC1) a curable component, comprising or consisting of: c1) a carbodiimide component, comprising or consisting of one or more than one open-chain carbodiimide compound and c2) a cyanate ester component, comprising or consisting of one or more than one cyanate ester compound, wherein the one or at least one of the more cyanate ester compounds is selected from the group consisting of cyanate ester compounds comprising two or more than two cyanate ester groups; andC2) a catalyst component suitable for catalysing curing of the curable component, or of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, wherein the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 5 to 5 : 1 , the mass ratio between the total mass of the curable component C1) and the total mass of any other curable substances present in the composition, is > 10 : 1 ; and wherein the use isas electrical insulation or as electrical insulation material in a printed circuit element and / or as a build-up film material in a printed circuit element.

2. Use according to claim 1 , wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula IwhereinR1and R2are each independently selected from the group consisting of a straightchain or branched alkyl group having 1 to 22, preferably 1 to 15, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an alkoxypolyoxyalkylene group,R3is a divalent residue formed by reaction of an organic diisocyanate compound OCN-R3-NCO with organic compounds carrying suitable groups reactive with the isocyanate groups of the organic diisocyanate compound;R4is a divalent residue formed by reaction of an organic diol compound HO-R4- OH with organic compounds carrying one or more than one isocyanate groups reactive with the hydroxy functional groups of the organic diol compound; wherein preferably the organic diol compound HO-R4-OH used for preparing the compound of formula I is selected from the group consisting of ethylene glycol, neopentylglycol, propylene glycol, 1 ,3-butanediol and 1 ,4-butanediol;X1and X2are each independently selected from the group consisting of -N=C=N-, - -OC(O)-N(H)-, -N(H)-C(O)-N(H)- and -N(R11)-C(O)-N(H)-, wherein R11is selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22, preferably 1 to 15 and more preferably 1 to 10, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18, preferably 6 to 12, carbon atoms and an aralkyl group having 7 to 20 carbon atoms, m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 39, preferably of from 0 to 20, more preferably of from 0 to 10 and even more preferably from 0 to 53. Use according to any of the preceding claims, wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula lawhereinR1ais a straight-chain or branched alkyl group having 1 to 10, preferably 2 to 10, and more preferably 2 to 8, carbon atoms;R3and R4have the meanings as defined in claim 2,m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 10, preferably of from 0 to 5.

4. Use according to any of claims 2 or 3, wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula I as defined in claim 2, or of formula la as defined in claim 3, wherein in each case the divalent residue R3is selected from the group consisting of a straight-chain or branched alkylene group having 1 to 22, preferably 1 to 15, carbon atoms; a straight-chain or branched alkylene group having 1 to 6, preferably 1 to 4, carbon atoms, where the alkylene group is substituted and / or interrupted by 1 or 2 cycloalkyl or cycloalkylene groups, each having 5 to 12, preferably 5 to 6 carbon atoms; a straightchain or branched alkylene group having 1 to 6, preferably 1 to 4, carbon atoms, where the alkylene group is substituted and / or interrupted by 1 or 2 aryl or arylene groups, each having 6 to 18, preferably 6 to 12 carbon atoms; a cycloalkylene group having 5 to 12, preferably 5 to 6, carbon atoms; and an arylen group having 6 to 18, preferably 6 to 12, carbon atoms, or selected from the divalent residues which can be obtained from diisocyanate compounds OCN-R3-NCO used in the reaction for producing the carbodiimide compound of formula I or of formula la, where the diisocyanate compound OCN- R3-NCO is selected from the group consisting of hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1 ,3-bis (isocyanatomethyl) cyclohexane, 1 ,4-bis (isocyanatomethyl) cyclohexane, 2,2-bis (4-isocyanatocyclohexyl) propane, isophorone diisocyanate, dicy-clohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, tol- ylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, diphenylmethane diisocyanate, 2,4,6-triisopropylbenzene-1 ,3-diyl diisocyanate, m-xylylene diisocyanate,1.3-bis (2-isocyanato-2-propyl) benzene and 1 ,4-bis (2-isocyanato-2-propyl) benzene, preferably selected from the group consisting of isophorone diisocyanate, dicy- clohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate,1 .3-bis-(2-isocyanato-2-propyl) benzene and 1 ,4-bis (2-isocyanato-2-propyl) benzene, and more preferably selected from the group consisting of dicyclohexylmethane- 4,4'-diisocyanate and dicyclohexylmethane-3,3'-diisocyanate; or selected from the group consisting of a divalent residue of formula IIa divalent residue of formula III,a divalent residue of formula IVand a divalent residue of formula Vwherein the character “#” denotes in each case the covalent bonding connection to the carbodiimide compound of formula I or of formula la, respectively.

5. Use according to any of the preceding claims, wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is a difunctional cyanate ester compound of formula VI(VI), whereinR11through R18are independently selected from the group consisting of hydrogen, linear C1-10 alkyl, halogenated linear C1-10 alkyl, branched C4-10 alkyl, halogenated branched C4-10 alkyl, C3-8 cycloalkyl, halogenated C3-8 cycloalkyl, linear C2-C10 alkenyl, branched C3-C10 alkenyl, C1-10 alkoxy, halogen, phenyl and phenoxy; wherein at least one of R11to R18is selected from the group consisting of linear C2-C10 alkenyl and branched C3-C10 alkenyl;Z1indicates a direct bond or a divalent moiety selected from the group consisting of -O-, -S-, -S(=O)-, -S(=O)2-, -CH2-, -CH(CH3)-, -C(CH3)2-,-CH(CF3)-, -C(CF3)2-, -C(=O)-, -C(=CH2)-, -C(=CCI2)-, -Si(CH3)2-, linear C1-10 alkanediyl, branched C4-io-alkanediyl, Cs-s-cycloalkanediyl, 1 ,2-phenylene, 1 ,3-phenylene, 1 ,4-phenylene, -N(R13)- wherein R13is selected from the group consisting of hydrogen, linear C1-10 alkyl, halogenated linear C1-10 alkyl,branched C4-10 alkyl, halogenated branched C4-10 alkyl, C3-8 cycloalkyl, phenyl and phenoxy, and moieties of formulaewherein X is independently selected from hydrogen and halogen; and oligomers, pre-polymers, polymers or mixtures thereof; wherein preferably the cyanate ester compounds of cyanate ester component c2) comprises or is a mixture of one or more compounds of formula VI and one or more compounds selected from the group consisting of: i) a polyfunctional cyanate ester compound of formula VIIn is an integer in the range of from 1 to 20; andR20and R21are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C4-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; ii) a polyfunctional cyanate ester compound of formula VIII-1(VIII-1) wherein n is an integer in the range of from 1 to 20; and R30, R31, R32and R33are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; iii) a polyfunctional cyanate ester compound of formula VIII-2(VIII-2) wherein n is an integer in the range of from 1 to 20; andR34, R35and R36are identical or different and independently from each other selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl;and oligomers, pre-polymers, polymers or mixtures thereof; iv) a polyfunctional cyanate ester compound of formula VI 11-3(VIII-3) wherein n is an integer in the range of from 1 to 20; andR37is selected from the group consisting of hydrogen, linear C1-10 alkyl, branched C3-10 alkyl, linear C2-C10 alkenyl, and branched C3-C10 alkenyl; and oligomers, pre-polymers, polymers or mixtures thereof; v) a polyfunctional cyanate ester compound of formula VIII-4wherein n is an integer in the range of from 1 to 20;and oligomers, pre-polymers, polymers or mixtures thereof.

6. Use according to any of the preceding claims, wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of - a compound of formula IX,wherein: k is 0 or 1 ,I is 0 or an integer in the range of from 1 to 10, R6and R7are the same or different and each represents a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, an alkyl halide group having from 1 to 20 carbon atoms, or halogen;R8represents a chemical group selected from the group consisting of the following members: -CH2-, -CH(CH3)-, -C(CH3)2-, -O-, -S-, -S(O)-, -(CH3)2C-benzyl-C(CH3)2- and dicyclopentadienyl,R9represents a chemical group selected from the group consisting of a divalent residue of formula Xwherein k, R6, R7and R8have the above meanings and the character “#” denotes in each case the covalent bonding connection to the compound of formula IX, and a divalent residue of formula XIwherein the character “#” denotes in each case the covalent bonding connection to the compound of formula IX, or a pre-polymer thereof; a compound or mixture of compounds of formula XIITr-[W-(Z)f / (H)l-f-W]r-1-[W-(Z)f / (H)l.f-(OCN)f / (R)l.f]r+2 (XII), whereinT is a 1 ,3,5-substituted-triazine moiety C3N3;W is an oxygen atom and is a linking atom between triazine and either component A or component B;Z is component A;H is component B;OCN is a cyanate ester end group of component A;R is a OH reactive end group of component B; r is an integer greater than or equal to 1 ; and f is a mol fraction of component A; wherein said compound or mixture of compounds is formed by chemical attachment of: a. at least one cyanate ester component A; b. at least one reactive intermediate component B, said component B being capable of copolymerization with said component A, said component B being a thermoplastic selected from the group consisting of (i) hydrogenated hydroxylated polybutadiene and (ii) polymethylphenylsiloxane containing between 3-9 mol-% OH functional groups.4,4'-isopropylidene diphenyl dicyanate; cyanic acid (1-methylethylidene)di-4,1 -phenylene ester homopolymer, (CAS RN 25722-66-1);4,4'-ethylidene diphenyl dicyanate; oligo(3-methylene-1 ,5-phenylcyanate) and mixtures thereof.

7. Use according to any of the preceding claims, wherein the composition for making an insulating thermosetting resin, comprisesC1) a curable component, consisting of:c1) in a total amount in the range of from 5 to 20 mass-%, relative to the total mass of said composition, a carbodiimide component, consisting of one or more than one open-chain carbodiimide compound, wherein the one, or at least one of the more, or all of the more, openchain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula IwhereinR1and R2are each independently selected from the group consisting of a straight-chain or branched alkyl group having 1 to 22 preferably 1 to 15, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14, carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms; an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an alkoxypolyoxyalkylene group,R3is a divalent residue selected from the group consisting of a divalent residue of formula IIa divalent residue of formula III,a divalent residue of formula IVand a divalent residue of formula Vwherein the character “#” denotes in each case the covalent bonding connection to the carbodiimide compound of formula I;R4is a divalent residue formed by reaction of an organic diol compound HO-R4-OH with organic compounds carrying one or more than one isocyanate groups reactive with the hydroxy functional groups of the organic diol compound; wherein preferably the organic diol compound HO-R4-OH used for preparing the compound of formula I is selected from the group consisting of ethylene glycol, neopentylglycol, propylene glycol, 1 ,3-butanediol and 1 ,4-butanediol;X1and X2are each independently selected from the group consisting of -N=C=N-, -OC(O)-N(H)-, -N(H)-C(O)-N(H)- and -N(R11)-C(O)- N(H)-, wherein R11is selected from the group consisting of a straightchain or branched alkyl group having 1 to 22, preferably 1 to 15 and more preferably 1 to 10, carbon atoms; an alicyclic aliphatic alkyl group having 4 to 22, preferably 7 to 14 carbon atoms, a cycloalkyl group having 3 to 12, preferably 6 to 12, carbon atoms;an aryl group having 6 to 18, preferably 6 to 12, carbon atoms and an aralkyl group having 7 to 20 carbon atoms, m is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; n is an integer in the range of from 1 to 20, preferably of from 1 to 10, more preferably of from 2 to 8; and p is an integer in the range of from 0 to 39, preferably of from 0 to 20, more preferably of from 0 to 10 and even more preferably from 0 to 5; and c2) a cyanate ester component, consisting of one or more than one cyanate ester compound, wherein the one or at least one of the more cyanate ester compounds is selected from the group consisting of cyanate ester compounds comprising two or more than two cyanate ester groups, wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX as defined in claim 6, a compound or mixture of compounds of formula XII as defined in claim 6;4,4'-isopropylidene diphenyl dicyanate; cyanic acid (1-methylethylidene)di-4,1-phenylene ester homopolymer, (CAS RN 25722-66-1);4,4'-ethylidene diphenyl dicyanate; oligo(3-methylene-1 ,5-phenylcyanate) and mixtures thereof.C2) a catalyst component suitable for catalysing curing of the curable component, wherein the catalyst component C2) is selected from the group consisting of catalytically active organic, nitrogen-containing compounds, catalytically active substances comprising organic, nitrogen-containing compounds and mixtures thereof, wherein the catalyst component C2) is selected from the group consisting of: imidazoles; tetraalkyl ammonium halides; bicyclic amino compounds; complexes comprising a Zn2+cation and one or more organic, nitrogencontaining compounds, and mixtures thereof;C3) a particulate inorganic filler, wherein the particulate inorganic filler is present in a total amount in the range of from 25 mass-% to 85 mass-%, relative to the total mass of said composition; andC5) an organic solvent;or of a thermosetting resin made from said composition, or of a thermoset polymer of said thermosetting resin, wherein the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 5 to 5 : 1 , the mass ratio between the total mass of the curable component C1) and the total mass of epoxy compounds present in the composition is > 10 : 1 .

8. Use according claim 7, wherein the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula lawhereinR1ais a straight-chain or branched alkyl group having 1 to 10, preferably 2 to 10, and more preferably 2 to 8, carbon atoms;R3and R4have the meanings as defined in claim 7, m is an integer in the range of from 1 to 10, preferably of from 2 to 8; n is an integer in the range of from 1 to 10, more preferably of from 2 to 8; andP is an integer in the range of from 0 to 10, preferably of from 0 to 5.

9. Use according to any of claims 7 or 8, wherein the composition for making an insulating thermosetting resin comprises as component c2): c2) a cyanate ester component, consisting of one or more than one cyanate ester compound, wherein the one or at least one of the more cyanate ester compounds is selected from the group consisting of cyanate ester compounds comprising two or more than two cyanate ester groups, wherein the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of: a compound or mixture of compounds of formula XII as defined in claim 6,4,4'-isopropylidene diphenyl dicyanate; cyanic acid (1 -methylethylidene)di-4,1-phenylene ester homopolymer, (CAS RN 25722-66-1);4,4'-ethylidene diphenyl dicyanate; oligo(3-methylene-1 ,5-phenylcyanate) and mixtures thereof.

10. Use according to any of the preceding claims, wherein the catalyst component C2) is selected from the group consisting of catalytically active organic, nitrogen-contain- ing compounds, catalytically active substances comprising organic, nitrogen-con- taining compounds and mixtures thereof, wherein the catalyst component C2) is selected from the group consisting of:imidazoles, preferably selected from the group consisting of 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethyl-1 -methylimidazole, 2-phenylimidazole, 1-cy- anoethyl-2-phenylimidazole, 1 -cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4.5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole,2.4.5-triphenylimidazole, 4-methyl-2-phenyl-1 / - / -imidazole, 2-methyl-4-phenyl-1 / - / -imidazole and mixtures thereof; more preferably selected from the group consisting of 2-ethyl-4-methylimidazole, 2-ethyl-1 -methylimidazole and mixtures thereof; tetraalkyl ammonium halides, preferably selected from the group consisting of tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide and mixtures thereof; bicyclic amino compounds, preferably selected from the group consisting of 1 ,8- diazabicyclo[5.4.0]undec-7-ene, 1 ,4-diazabicyclo[2.2.2]octan and mixtures thereof; complexes comprising a divalent metal cation, preferably a Zn2+-ion, and one or more organic, nitrogen-containing compounds, preferably selected from the group consisting of a complex comprising ZnCh and a tetraalkyl ammonium halide, preferably tert, butyl ammonium bromide; and ZIF-8, and mixtures thereof, wherein preferably the catalyst component is selected from the group consisting of bicyclic amino compounds, preferably selected from the group consisting of 1 ,8- diazabicyclo[5.4.0]undec-7-ene, 1 ,4-diazabicyclo[2.2.2]octan and mixtures thereof; imidazoles selected from the group consisting of 2-ethyl-4-methylimidazole, 2- ethyl-1 -methylimidazole and mixtures thereof;and complexes comprising a divalent metal cation, preferably a Zn2+-ion, and one or more organic, nitrogen-containing compounds, preferably selected from the group consisting of a complex comprising ZnCh and a tetraalkyl ammonium halide, preferably tetrabutyl ammonium bromide; and ZIF-811 . Use according to any of the preceding claims, wherein in the curable component C1) the mass ratio between the total mass of the cyanate ester component c2) and the total mass of the carbodiimide component c1) is in the range of from 1 : 3 to 3 : 1 , preferably of from 1 : 2.5 to 2.5 : 1 and more preferably of from 1 : 2 to 2 : 1 ; and / or the mass ratio between the total mass of the curable component C1) and the total mass of epoxy compounds present in the composition is > 20 : 1 , preferably > 25 : 1 . and / or the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula la as defined in any of claims 3 or 4 and the one or at least one of the more, or all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX and a compound or mixture of compounds of formula XII as defined in claim 6, preferably is selected from a compound or mixture of compounds of formula XII as defined in claim 6.

12. Use according to any of the preceding claims, wherein the composition for making a thermosetting resin further comprises:C3) a particulate inorganic filler, selected from the group consisting of silica, silane surface-modified silica, boehmite, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, aluminium oxide, titanium oxide, zinc oxide, zinc borate, zinc stannate, magnesium oxide, zirconium oxide, boron nitride, silicon nitride, aluminium nitride, barium sulfate and mixtures thereof; wherein preferably the particulate inorganic filler comprises silica and / or silane surface-modified silica or the particulate inorganic filler is selected from the group consisting of silica and silane surface-modified silica; wherein the particulate inorganic filler is present in a total amount in the range of from 25 mass-% to 85 mass-%, preferably of from 30 mass-% to 80 mass- % and more preferably of from 60 mass-% to 75 mass-%, relative to the total mass of said composition; and / orC4) a particulate organic filler, preferably selected from the group consisting of polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen, silicone resin powder, silicone rubber powder, silicone composite powder, styrene-based powder, butadiene-based powder, acryl-based powder; core shell-type rubber powders and mixtures thereof, wherein preferably the particulate organic filler comprises polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen and mixtures thereof, or the particulate organic filler is selected from the group consisting of polytetrafluorethylen, vinyl amino surface-modified polytetrafluorethylen, phenyl amino surface-modified polytetrafluorethylen and mixtures thereof; and / orC5) an organic solvent, selected from the group consisting of acetone, methyl ethyl ketone, cyclohexanone, methyl cellosolve, toluene, xylene, N,N-dimethyl formamide, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and mixtures thereof, wherein more preferably the organic solvent comprises or is methyl ethyl ketone; and / orC6) one or more members from the group consisting of impact modifiers, flow additives, flame retardants, coloring agents, particle dispersion aids and surfactants.

13. Use according to any of the preceding claims of an insulating thermosetting resin, wherein said insulating thermosetting resin is obtained from a composition for making an insulating thermosetting resin as defined in any of claims 1 to 12, by a curing process comprising thermal curing, preferably at a temperature in the range of from 120 °C to 210 °C, more preferably of from 140 °C to 200 °C; and / or is in the form of a web or film.

14. Composition for making an electrically insulating thermosetting resin, electrically insulating thermosetting resin made from said composition, or electrically insulating thermoset polymer of said electrically insulating thermosetting resin, as defined in any of claims 1 to 13, wherein preferably the one, or at least one of the more, or all of the more, open-chain carbodiimide compounds of the carbodiimide component c1) is an open-chain carbodiimide compound of formula la as defined in any of claims 3 or 4and the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound of formula IX and a compound or mixture of compounds of formula XII as defined in claim 6, preferably the one or at least one of the more, or (preferably) all of the more, cyanate ester compounds of cyanate ester component c2) is selected from the group consisting of a compound or mixture of compounds of formula XII as defined in claim 6.

15. Layer composite, comprising at least the following layers:L1) a carrier layer, comprising or consisting of an organic polymer, preferably comprising or consisting of polyethylene terephthalate,L2) a layer comprising or consisting of a composition for making an electrically insulating thermosetting resin; an electrically insulating thermosetting resin or an electrically insulating thermoset polymer, all according to claim 14, andL3) a covering layer, disposed on the layer L2). wherein preferably the layer L2) is arranged between, and preferably in contact with, the two layers L1) and L3); and / or is disposed on and in contact with layer L1).

16. Printed circuit element, preferably multilayer printed circuit assembly, comprising: at least one conductor layer andat least one electrically insulating layer comprising a composition for making an electrically insulating thermosetting resin; an electrically insulating thermosetting resin or an electrically insulating thermoset polymer, all as defined in any of claims 1 to 13, where the at least one electrically insulating layer is disposed on and preferably in contact with a surface of the at least one conductor layer.

17. Method of making a printed circuit element, preferably a multilayer printed circuit assembly, comprising at least the following steps:M1) providing or preparing an electrically insulating thermosetting resin made from a respective composition as defined in any of claims 1 to 13, or as defined in claim 14;M2) providing or preparing a precursor of a printed circuit element having on at least one of its surfaces a first conductive pattern, preferably comprising or consisting of copper metal;M3) applying the electrically insulating thermosetting resin from step M1) to the surface of at least a part of the first conductive pattern of the precursor of the printed circuit element from step M2), and optionally further pre-curing said insulating thermosetting resin, to receive a layer of an electrically insulating thermosetting resin, disposed on at least a part of said first conductive pattern;M4) arranging one or more connecting holes at defined positions of said layer of an electrically insulating thermosetting resin;M5) applying to or disposing on said layer of an electrically insulating thermosetting resin received in step M3), including the connecting holes, in one or more steps, a second conductive pattern, preferably comprising or consisting of copper metal; where the second conductive pattern is separated from the first conductive pattern by the optionally further pre-cured electrically insulating thermosetting resin received including the connecting holes, and is in contact with the first conductive pattern at least at some of the one or more connecting holes,M6) Further curing the electrically insulating thermosetting resin separating the first and second conductive patterns, preferably at a temperature in the range of from 100 °C to 200 °C, preferably in the range of from 120 °C to 180 °C, preferably to result in a printed circuit element comprising a layer of an elec- trically insulating thermoset polymer.

18. Pre-impregnated fiber article, comprising a fiber substrate impregnated with an electrically insulating thermosetting resin according to claim 14.

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