EP4677004A1 - Bismaleimide compounds and low dielectric resin composition comprising them - Google Patents

Abstract

Bismaleimide compounds of the formula (I) wherein R1 is a divalent aliphatic radical and R2 is a divalent aromatic radical; And resin compositions comprising said bismaleimide compounds of the formula (I), having a low dielectric constant (Dk), a low dielectric dissipation factor (Df) and a high glass transition temperature (Tg).

Description

BISMALEIMIDE COMPOUNDS AND LOW DIELECTRIC RESIN COMPOSITION COMPRISING THEM

FIELD

[0001] The present disclosure relates to new bismal eimide compounds and to resin compositions comprising said compounds, to their process of manufacturing and to their uses in various applications, such as, in the production of a prepreg, a laminated board for printed wiring board, a molding material and an adhesive. The resin compositions provide a cured product having high heat resistance, low water absorption and excellent dielectric properties. Such advantageous properties are required for organic insulating materials for use in electronic equipment such as communication equipment.

BACKGROUND

[0002] With the development of wireless network and satellite communications, electronic products are trending toward the need for higher speed, frequency and larger capacity for the transmission of voice, video and data. In addition, as these electronic products become thinner and smaller, electrical circuit boards tend to increase in complexity, density and multi-layer stratification. In order to maintain the high rate of transmission and signal integrity, printed circuit boards (“PCB”) have a need for materials with a low dielectric constant (Dk) and low dielectric loss (sometimes also called loss factor or dissipation factor, Df) thereby resulting in lower signal loss.

[0003] Polymer insulating materials are usually used as substrate materials for PCB’s. The laminate for the PCB is either made of the polymer insulating material alone or by blending the polymer insulating material with glass, fiber, nonwoven fabric, inorganic filler or the like. Epoxy resins have traditionally been employed due to their low cost and high heat and chemical resistant properties when cured. However, because of their relatively high dielectric constant and high dielectric loss tangent, it is difficult to achieve a suitable low dissipation factor at high frequency signals. Polyphenylene ether (PPO) resins have also been used in laminates due to their lower dielectric constants and dissipation properties, but the use of high frequency signals in new electronic fields require even lower dielectric loss constants and dissipation factors. Fluoro resins, typically represented by polytetrafluoroethylene (PTFE), have low dielectric constants and dissipation factors, but they are thermoplastic resins and therefore undergo large expansion and shrinkage during molding and processing and are materials that are not easily handled.

[0004] Other types of resins are known but cannot reach a low dielectric loss value Df, which is needed in view of the demands in the high frequency signal transmissions.

[0005] Bismaleimide compounds are well known in formulation for electronic materials: [0006] EP 3135722 discloses a heat-curable resin composition for use in electric and electronics industry which is suitable as an underfill and for performing potting. The heat- curable resin composition contains a heat-curable resin and a bismaleimide compound in liquid form at 25°C.

[0007] US 7,884,174 discloses imide-extended mono-, bis-, or polymaleimide compounds and their use for the preparation of thermosetting adhesive compositions which find application for a variety of purposes in the fabrication and assembly of semiconductor packages and microelectronic devices.

[0008] US 3,856,752 discloses aromatic polyimides with improved solubility in polar organic solvents and their use as adhesives, laminating resins, especially for printed circuit boards, fibers, coatings, for decorative and electrical purposes, films, wire enamels and molding compounds.

[0009] However, prior art bismaleimide and aromatic polyimides compounds suffer drawbacks due to limited solubility and humidity sensitivity.

[0010] There remained the need for a resin composition capable to be used in electronic equipment and providing a higher dissipation factor and/or a higher decomposition temperature.

[0011] There remained the need to provide a curable bismaleimide compound giving access to a resin composition with improved properties, in particular in terms of Df, thermomechanical properties, humidity resistance, and which can be easily processable. There is a need to improve high speed signal transmission, whilst reducing power and interference problems in electronic applications. This requires a material composition with improved dielectric properties, while guaranteeing thermomechanical properties and easy manufacturing required for high volume sustainable production of printed circuit boards and antennas. [0012] It is an object of the present invention to overcome the aforementioned drawbacks of the prior art resin compositions and provide improved polymer insulating materials having sufficient thermomechanical properties, humidity resistance, low dielectric characteristics and being easily processable to cope with the ever increasing high frequency signal transmissions.

SUMMARY

[0013] The invention relates to novel bismaleimide compounds of the following formula (I):

Formula (I)

Wherein n is an integer, n ranges from 1 to 10, m is an integer, m ranges from 1 to 10,

Each Q, independently, is a tetravalent radical selected from C6-C50 hydrocarbons comprising at least one aromatic group and optionally one or more heteroatoms selected from O, N, S, F, Cl, Br,

Each Rl, independently, is a divalent radical selected from aliphatic and aromatic, linear or branched, C1-C60 hydrocarbons, optionally comprising one or more NH2 group, or one or more NH bridges,

Each R2, independently, is a divalent radical selected from C6-C54 aromatic hydrocarbons, optionally comprising one or more halogen atoms,

R is a divalent radical selected from Rl and R2,

Each Y, independently, is H or CH3 [0014] The invention also relates to novel bismaleimide compounds resulting from a method comprising the following steps:

Formula (I)

• Step 1 : Reacting a dianhydride (IV) with a diamine of the formula (II) and a diamine of the formula (III) to obtain an amine terminated extended imide (V),

• Step 2: Reacting the amine terminated extended imide resulting from step 1 with a maleic anhydride compound (VI).

Wherein n, m, Q, Rl, R2, R and Y have the same definition as in formula (I) above,

An and Am, respectively, represent the relative molar amount of the diamine H2N-RI-NH2 and the diamine H2N-R2-NH2 introduced in the reaction medium with regards to the amount of dianhydride.

[0015] The present invention also relates to a curable resin composition comprising at least a bismaleimide compound as above disclosed and at least a heat-curable resin.

[0016] The present invention further concerns a process for manufacturing an article, comprising at least the following steps:

- Step 1 : Preparing a curable resin composition comprising at least a bismaleimide compound as above disclosed and a heat-curable resin,

- Step 2:

Shaping the composition,

- Step 3 :

Partially or fully curing the composition.

[0017] The invention also relates to articles obtained by said method, including a cured resin, a sheet-like cured resin, a laminated body, a prepreg, electronic parts, and single and multilayer circuit boards comprising the resin compositions of the present disclosure.

[0018] The invention also relates to the use of the resin composition as above defined in a prepreg, a metal clad laminate, a printed circuit board, a light emitting diode, an electronic coating, a textile, a polymer molding compound, a medical molding compound and an adhesive.

[0019] Bismaleimide compounds according to the invention show an optimized performance between thermomechanics (glass transition) and low dielectric constant and low loss at high frequencies, improved solubility in solvents such as MEK (Methyl Ethyl Ketone), cyclohexanone, toluene, xylene along with processing characteristics suitable for formulation of electronic materials to improve dielectric and thermomechanical properties.

DETAILED DESCRIPTION

[0020] The present disclosure is generally directed to novel bismaleimide compounds and to resin compositions obtained from these novel bismaleimide compounds, said resins having a low dielectric constant (Dk), a low dielectric dissipation factor (Df) and excellent thermomechanical properties, such as high thermal stability, good processability, high peel strength, good moisture resistance and/or a high glass transition temperature (Tg). In attempting to achieve the objects of the present disclosure, it was surprisingly discovered that when a resin composition is made with the above-described bismaleimide compounds, a significant reduction in Df can be achieved as compared to a resin composition containing state of the art resins, while having a high Tg. The novel resin composition, as a whole, exhibits a low Dk and low Df (typically Df < 0.003) in the gigahertz range (e.g., 1-10 GHz) allowing it to meet the rigorous required industrial standards in a variety of applications, such as prepregs, metal clad laminates, printed circuit boards, light emitting diodes and electronic coatings. It shows high thermomechanical performance (high Tg) and high solubility (> 50wt% in typical CCL (copper clad laminate) solvents such as toluene, MEK). [0021] The novel bismal eimide compounds and resin compositions may also find use in chip design (Integrated Circuit (IC) packaging), coatings, Chemical Vapour Deposition (CVD) and photo chemistry. Further, they could be used for the preparation of membrane, filters, and high performance coatings, fibre reinforced composites and adhesives. The novel bismaleimide compounds can also be used as intermediate for formulators for radical and condensation polymerisation.

[0022] The following terms shall have the following meanings:

[0023] The term "comprising" and derivatives thereof are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. In order to avoid any doubt, all compositions claimed herein through use of the term "comprising" may include any additional additive, adjuvant, or compound, unless stated to the contrary. In contrast, the term, "consisting essentially of' if appearing herein, excludes from the scope of any succeeding recitation any other component, step or procedure, except those that are not essential to operability and the term "consisting of', if used, excludes any component, step or procedure not specifically delineated or listed. The term "or", unless stated otherwise, refers to the listed members individually as well as in any combination.

[0024] The articles "a" and "an" are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical objects of the article. By way of example, "a crosslinker" means one crosslinker or more than one crosslinker. The phrases "in one embodiment", "according to one embodiment" and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one embodiment of the present disclosure and may be included in more than one embodiment of the present disclosure. Importantly, such phrases do not necessarily refer to the same aspect. If the specification states a component or feature "may", "can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic. [0025] The term “about” as used herein can allow for a degree of variability in a value or range, for example, it may be within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range.

[0026] Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but to also include all of the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range such as from 1 to 6, should be considered to have specifically disclosed sub-ranges, such as, from 1 to 3, from 2 to 4, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. [0027] The terms “preferred” and “preferably” refer to embodiments that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the present disclosure.

[0028] The term "in the range" or "within a range" (and similar statements) includes the endpoints of the stated range.

[0029] Where substituent groups are specified by their conventional chemical formula, written from left to right, they equally encompass the chemically identical substituents that would result from writing the structure from right to left, for example, -CH2O- is equivalent to -OCH2-.

[0030] The term “optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0031] The term “alkyl” refers to a linear or branched hydrocarbyl radical having 1 to 50 carbon atoms, and “substituted alkyl” refers to an alkyl further bearing one or more substituents selected from but not limited to hydroxy, alkoxy, mercapto, cycloalkyl, heterocyclic, aryl, heteroaryl, aryloxy, halogen, trifluoromethyl, cyano, nitro, nitrone, amino, amido, C(O)H, acyl, oxyacyl, carboxyl, carbamate, sulfonyl, sulfonamide, and sulfuryl. [0032] The term “alkenyl” refers to a linear or branched hydrocarbyl radical having 2 to 50 carbon atoms and at least one carbon-carbon double bond.

[0033] The term “alkynl” refers to a linear or branched hydrocarbyl radical having 2 to 50 carbon atoms and at least one carbon-carbon triple bond.

[0034] The term “aromatic” refers to a hydrocarbyl radical having 6 to 50 carbon atoms that contains at least one ring with delocalised pi electrons, such as a benzene ring.

[0035] The term “aralkyl” refers to any univalent radical derived from an alkyl radical by replacing one or more hydrogen atoms by aryl groups.

[0036] The terms “dielectric dissipation factor (Df)” and “loss tangent,” as used herein, are synonymous and refer to the amount of energy dissipated (i.e., electrical loss) into an insulating material when a voltage is applied to the circuit. Df represents the loss of the signal in the circuit.

[0037] The terms “dielectric constant (Dk)” and “permittivity,” as used herein, are synonymous and refer to a measurement of the relative capacitance of an insulating material to that of air or vacuum. The dielectric constant determines the speed of the electronic signal.

[0038] The term glass transition temperature” or “T_g,” as used herein, means the temperature at which the amorphous domains of a polymer take on the characteristic properties of the glass state-brittleness, stiffness, and rigidity. The term further means the temperature at which cured resins undergo a change from a glassy state to a softer more rubbery state.

[0039] The bismaleimide compounds

[0040] According to a first aspect, the invention relates to novel bismaleimide compounds of the following formula (I):

Formula (I)

Wherein n is an integer, n ranges from 1 to 10, preferably n ranges from 1 to 5, m is an integer, m ranges from 1 to 10, preferably n ranges from 1 to 5,

Each Q, independently, is a tetravalent radical selected from C6-C50 hydrocarbons comprising at least one aromatic group and optionally one or more heteroatoms selected from O, N, S, F, Cl, Br,

Each Rl, independently, is a divalent radical selected from aliphatic and aromatic, linear or branched, C1-C60 hydrocarbons, optionally comprising one or more NH2 group and/or one or more NH bridges,

Each R2, independently, is a divalent radical selected from C6-C54 aromatic hydrocarbons, optionally comprising one or more halogen atoms,

R is a divalent radical Rl or R2,

Y represents H or CH3. Preferably Y is H.

[0041] Q is the tetraval ent radical present in the aromatic dianhydride which has reacted with the diamine H2N-RI-NH2 and the diamine H2N-R2-NH2.

[0042] As examples of radical Q one can mention the following structures:

With Q’ a divalent radical that can be selected from C1-C38 hydrocarbons optionally comprising one or more heteroatoms selected from O, N, S, F, Cl, Br.

For example Q’ can be -CO-, -CO-NH-, -CO-O-, -O-CO-O-, -NH-CO-NH-, a divalent Cl- C40 alkyl radical, a divalent C1-C40 alkenyl radical, a divalent C1-C40 alkynyl radical, said alkyl, alkenyl or alkynyl radical optionally comprising one or more -O- bridges, one or more -NH- bridges, one or more substituents selected from -OH, NH2, COOH, CONH2, -SH, -SO3H, a halogen atom.

[0043] According to a favorite embodiment Q is selected from the following radicals:

[0044] Each Rl, independently, is a divalent radical selected from aliphatic and aromatic, linear or branched, C1-C60 hydrocarbyls, optionally comprising one or more NH2 group, one or more NH bridges. Preferably Each Rl, independently, is a divalent radical selected from C1-C60 alkyl, C2-C60 alkenyl, C2-C60 alkynyl, C6-C60 aralkyl, optionally comprising one or more NH2 group, one or more NH bridges.

[0045] Each Rl, independently, can be linear or branched.

[0046] Advantageously, each Rl, independently, is selected from C1-C60 alkyl, alkenyl or aralkyl, optionally comprising one or more NH2 group, one or more NH bridges, preferably from C 12-C60 alkyl, alkenyl or aralkyl, optionally comprising one or more NH2 group, one or more NH bridges.

[0047] More advantageously, each Rl is, independently, selected from dimeric and trimeric hydrocarbon groups with a total number of C atoms from 12 to 60, and their mixtures.

[0048] Advantageously, Rl is selected from linear, branched, or cyclic alkyl or alkenyl, or aromatic hydrocarbons with a total number of C atoms from 12 to 60, and their mixtures.

[0049] Each R2, independently, is a divalent radical selected from aromatic C6-C54 hydrocarbons.

[0050] Preferably, R2 is an aromatic C6-C54 divalent radical comprising a phenylindane group.

[0051] Advantageously, R2 is selected from divalent radicals of the formula (IIIA)

Formula (I HA)

Wherein

Yl, Y2, independently, represent H, a C1-C5 alkyl,

Each Y3, Y4, independently, represents H, a halogen, a C1-C4 alkyl.

When Y3 and/or Y4 is a halogen, preferably it is Cl.

Preferably, in formula (IIIA), all Y3 and Y4 represent H.

Preferably, in formula (IIIA), Yl, Y2, independently, represent H or a methyl group.

According to an embodiment, Yl and Y2 represent CH3.

Preferably, in formula (IIIA), radical substituents are located on positions 5’ or 6’ and on position 4’.

[0052] The preparation of the bi smal eimide compound

[0053] The invention also relates to novel bismaleimide compounds resulting from a method comprising the following steps:

Formula (I)

• Step 1 : Reacting a dianhydride (IV) with a diamine of the formula (II) and a diamine of the formula (III) to obtain an amine terminated extended imide (V),

• Step 2: Reacting the amine terminated extended imide (V) resulting from step 1 with a maleic anhydride compound (VI).

Wherein n, m, Q, Rl, R2, R and Y have the same definitions and preferred embodiments as in formula (I) above,

An and Am, respectively, represent the relative molar amounts of the diamine H2N-RI- NH2 (II) and the diamine H2N-R2-NH2 (III) introduced in the reaction medium with regards to the amount of dianhydride (IV).

[0054] As examples of aromatic dianhydride (IV), one can mention: pyromellitic dianhydride; 1,4,5,8-naphthalenetetracarboxylic dianhydride; 2, 3,6,7- naphthalenetetracarboxylic acid dianhydride; 1,2,4,5-naphthalenetetracarboxylic acid dianhydride; 1,2,5,6-naphthalenetetracarboxylic acid dianhydride; benzene-1, 2,3,4- tetracarboxylic acid dianhydride; pyrazine-2,3,5,6-tetracarboxylic acid dianhydride; thiophene-2, 3, 4, 5-tetracarboxylic acid dianhydride; 3,4,9, 10-perylenentetracarboxylic dianhydride; 2,3,9, 10-perylene tetracarboxylic acid dianhydride; 2,6-dichloronaphthalene- 1,4,5,8-tetracarboxylic acid dianhydride; 2,7-dichloronaphthalene-l,4,5,8-tetracarboxylic acid dianhydride; 2,3,6,7-tetrachloronaphthalene-l,4,5,8-tetracarboxylic acid dianhydride; phenanthrene- 1,8, 9, 10-tetracarboxylic acid dianhydride;

3,3',4,4'-benzophenone tetracarboxylic dianhydride; 2, 2', 3,3'- benzophenonetetracarboxylic acid dianhydride; 3,3',4,4'-biphenyl tetracarboxylic dianhydride; 2,2',3,3'-biphenyltetracarboxylic acid dianhydride; 4,4'-oxydiphthalix anhydride; 3,3'-oxydiphthalic anhydride; 4,4'-isopropylidenediphthalic anhydride; 3,3'- isopropylidenediphthalic anhydride; 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride; 4,4'-sulfonyldiphthalic anhydride; 4,4'-methylenediphthalic anhydride; 4,4'-thiodiphthalic anhydride; 4,4'-ethylidenediphthalic anhydride; 2,2'-bis(3,4- dicarboxyphenyl)hexafluoropropane dianhydride; 4,4'-bisphenol A diphthalic anhydride; ethylene glycol bis(trimellitate anhydride); hydroquinone diphthalic anhydride.

[0055] According to a favorite embodiment, the aromatic dianhydride (IV) is pyromellitic dianhydride or 3,3',4,4'-benzophenone tetracarboxylic dianhydride.

[0056] Amines of formula (II) are commercially available. Examples of di-amines (II), NH2-RI-NH2, that can be used according to the invention, include: 1,10-diaminodecane; 1,12-diaminododecane; l,18-diamino-6, 8-dialkylene; dimer diamine like C36-alkylene diamines; trimeric amines like C54 trimeric amine; l,2-diamino-2-methylpropane; 1,2- diaminocyclohexane; 1,2-diaminopropane; 1,3-diaminopropane; 1,4-diaminobutane; 1,5- diaminopentane; 1,7-diaminoheptane; 1,8-diaminomenthane; 1,8-diaminooctane; 1,9- diaminononane; 3,3'-diamino-N-methyldipropylamine; 1,3 -diaminopentane; 1,3- bisaminomethylcyclohexane; polyoxyalkylenediamines (e.g. Huntsman's Jeffamine D- 230, D400, D-2000, and D-4000 products); l,3-cyclohexanebis(methylamine); bis(4- amino-3-methylcyclohexyl)methane; l,2-bis(2-aminoethoxy)ethane; 3(4), 8(9)- bis(aminomethyl)tricyclo(5.2.1 ,0<2,6> )decane.

As examples of amines, one can mention mixtures of amines commercialized by Croda under the reference Priamine 1075 (mainly dimeric amine) or Priamine 1071 (includes mix of dimeric amine C36 and trimeric amine C54).

Other examples of amines from which the group R1 can be obtained, being amines deriving from dimerized fatty acids, are illustrated on the scheme below:

[0057] Preferably, di-amines (II), NH2-RI-NH2, are selected from aliphatic C12-C60 dimer diamines, C12-C60 trimer triamines and mixtures thereof.

[0058] Examples of aromatic di-amines (III), NH2-R2-NH2, that can be used according to the invention include DAPI(4',5-6-Diamino-l,3,3-trimethyl-l-phenylindane); 9,10- diaminophenanthrene; 4,4'-diaminooctafluorobiphenyl; 3,5-diaminobenzoic acid; 3,7- diamino-2-m ethoxyfluorene; 4,4'-diaminobenzophenone; 3,4-diaminobenzophenone; 3,4- diaminotoluene; 2,6-diaminoanthraquinone; 2,6-diaminotoluene; 2,3-diaminotoluene; 1,8- diaminonaphthalene; 2,4-diaminotoluene; 2,5-diaminotoluene; 1,4-diaminoanthraquinone; 1,5-diaminoanthraquinone; 1,5-diaminonaphthalene; 1,2-diaminoanthraquinone; 2,4- cumenediamine; 1,3 -bisaminomethylbenzene; 2-chloro-l,4-diaminobenzene; 1,4- diamino-2,5-di chlorobenzene; l,4-diamino-2,5-dimethylbenzene; 4,4'-diamino-2,2'- bistrifluorom ethylbiphenyl; bis(amino-3-chlorophenyl)ethane; bis(4-amino-3,5- dimethylphenyl)methane; bis(4-amino-3,5-diethylphenyl)methane; bi s(4-amino-3 -ethyl diaminofluorene; diaminobenzoic acid; 2,3-diaminonaphthalene; 2,3-diaminophenol; -5- methylphenyl)m ethane; bi s(4-amino-3-methylphenyl)m ethane; bis(4-amino-3- ethylphenyl)methane; 4,4'-diaminophenylsulfone; 3,3'-diaminophenylsulfone; 2,2-bis(4,- (4-aminophenoxy)phenyl)sulfone; 2,2-bis(4-(3-aminophenoxy)phenyl)sulfone; 4,4'- oxydianiline; 4,4'-diaminodiphenyl sulfide; 3, 4'-oxy dianiline; 2,2-bis(4-(4- aminophenoxy)phenyl)propane; l,3-bis(4-aminophenoxy)benzene; 4,4'-bis(4- aminophenoxy)biphenyl; 4,4'-diamino-3,3'-dihydroxybiphenyl; 4,4'-diamino-3,3'- dimethylbiphenyl; 4,4'-diamino-3,3'-dimethoxybiphenyl; Bisaniline M; Bisaniline P; 9,9- bis(4-aminophenyl)fluorene; o-tolidine sulfone; methylene bis(anthranilic acid); l,3-bis(4- aminophenoxy)-2,2-dimethylpropane; l,3-bis(4-aminophenoxy)propane; l,4-bis(4- aminophenoxy)butane; l,5-bis(4-aminophenoxy)butane; 2,3,5,6-tetramethyl-l,4- phenylenediamine; 3,3',5,5'-tetramethylbenzidine; 4,4'-diaminobenzanilide; 2,2-bis(4- aminophenyl)hexafluoropropane; m-xylylenediamine; p-xylylenediamine.

[0059] Some phenylindane amines are commercially available. Others may be prepared by methods disclosed in US3,856,752, the contents of which are incorporated herein by reference.

[0060] Preferably, di-amines (III), NH2-R2-NH2 are selected from DAPI(4',5-6-Diamino- 1 ,3, 3 -trimethyl- 1 -phenylindane).

[0061] Preferably, according to the invention, the ratio of the sum of amines (Am + An) to dianhydride compound ranges from about 5: 1 to about 1.05: 1, more preferably from about 3 : 1 to about 1.1 : 1, even more preferably from about 2: 1 to about 1.2: 1, and according to a preferred embodiment about 1.5: 1.

[0062] Preferably, according to the invention, the molar ratio Am / An, of aromatic amine(s) to aliphatic amine(s), ranges from about 20: 1 to about 1 : 1, more preferably from about 10 : 1 to about 2: 1, even more preferably from about 5 : 1 to about 3:1, advantageously about 4: 1.

[0063] Preferably, the maleic anhydride compound (VI) is maleic anhydride.

[0064] The amount of maleic anhydride compound is selected in order to obtain a product whose extremities are capped by the maleimide group at both extremities.

[0065] According to a preferred embodiment, the first step of the method for the preparation of the bismaleimide compound of formula (I) proceeds in two sub-steps: • Sub-step 1 a: the reaction of the dianhydride (IV) with the aliphatic diamine of formula H2N-RI-NH2 (II),

• Sub-step 1 b: the reaction of the product resulting from Sub-step 1 a with the aromatic diamine H2N-R2-NH2, resulting in an amine terminated extended imide (V).

[0066] Advantageously, the method for the preparation of the bismaleimide compound of formula (I) is implemented in one pot, without isolating intermediate compounds, like the amine terminated extended imide (V).

[0067] The reaction mixture comprises a mixture of compounds of formula (I), wherein Rl, R2, Y, n, m may vary according to the parameters selected for performing the reaction. The skilled professional is familiar with the preparation of bismaleimide compounds and understands other products may be present in the reaction mixture in addition to the compounds of formula (I) according to the invention and intermediate compounds. For example, the mixture may comprise some compounds of formula (I) wherein n = 0 and some compounds of formula (I) wherein m = 0.

[0068] The curable resin composition

[0069] The bismaleimide compound of formula (I), and/or the bismaleimide compound resulting from the above disclosed method advantageously represents from about 20 to about 99%, more preferably from about 30 to about 98% by weight of the total weight of the resin composition.

[0070] In addition to the bismaleimide compound of formula (I), and/or the bismaleimide compound resulting from the above disclosed method, the resin composition advantageously comprises a co-curing agent or heat curable resin.

[0071] Using a co-curing agent in the resin composition permits to reduce the curing temperature or promote the curing reaction. According to a favorite embodiment, the composition of the invention includes at least a co-curing agent or heat curable resin, which can be selected from, for example, polyphenylene ether derivatives, maleimides, styrenes, divinylbenzenes, trivinylcyclohexanes, trialkenyl isocyanurate compounds and mixtures thereof.

[0072] Advantageously, the co-curing agent is selected from trialkenyl isocyanurate compounds such as triallyl isocyanurate (TAIC). [0073] The amount of co-curing agent used is adapted according to the content of unsaturated groups contained in the curable resin composition, the choice of a particular co-curing agent, its half-life temperature and required stability. In one embodiment, the curable resin composition of the present invention may include the co-curing agent and mixtures thereof in an amount within a range of about 1% to about 50% by weight or within a range of about 2% to about 20% by weight based on the total weight of the additivated composition.

[0074] Additional components

[0075] Before curing, the curable resin composition can be mixed with varied additives selected according to the intended application and expected properties. Such additives are detailed here-under in a non-limiting manner. In this chapter, the percentages are expressed by weight of additional compounds with regards to the total weight of the additivated resin composition.

[0076] Although the resin composition of the present disclosure may be cured by mere heating, a curing catalyst that generates a free radical species may be added in order to improve the curing efficiency. Examples of such curing catalysts include, but are not limited to, benzoin type compounds such as benzoin and benzoin methyl, acetophenone type compounds such as acetophenone and 2,2-dimethoxy-2-phenylacetophenone and the like; thioxanthone type compounds such as thioxanthone and 2,4-diethylthioxanthone, bisazide compounds such as 4,4'-diazidochalcone, 2,6-bis(4-azidobenzal)cyclohexanone and 4,4'-diazidobenzophenone, azo compounds such as azobisisobutyronitrile, 2,2- azobispropane, m.m'-azoxy-styrene and hydrazone, organic peroxides such as 2,5- dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3 and dicumyl peroxide.

[0077] The resin composition may contain the curing catalyst in an amount of about 0.1%- 10% by weight or about 0.3%-7% by weight or about 0.5%-5% by weight or about l%-3% by weight, where the % by weight is based on the total weight of the resin composition.

[0078] In another embodiment, a polymerization inhibitor may optionally be added to the resin composition in order to enhance the storage stability. Examples include quinones and aromatic diols such as hydroquinone, p-benzoquinone, chloranil, trimethylquinone and 4-t-butylpyrocatechol. The resin composition may include from about 0.0005%-5% by weight of the polymerization inhibitor when present, where the % by weight is based on the total weight of the resin composition.

[0079] In another embodiment, the resin composition may optionally include an inorganic filler, organic filler or mixture thereof. Fillers contemplated for use in the practice of the present disclosure may be any of a variety of morphologies, e.g., angular, platelet, spherical, amorphous, sintered, fired, powder, flake, crystalline, ground, crushed, milled, and the like, or mixtures of any two or more thereof. Presently preferred particulate fillers contemplated for use herein are substantially spherical.

[0080] Such fillers may optionally be thermally conductive. Both powder and flake forms of filler may be used in the resin compositions of the present disclosure. Fillers having a wide range of particle sizes can also be employed in the practice of the present disclosure. Particle sizes ranging from about 500 nm up to about 300 microns may be employed, with particle sizes of less than about 100 microns being preferred, and particle sizes in the range of about 5 up to about 75 microns being particularly preferred.

[0081] A wide variety of fillers can be employed in the practice of the present disclosure, e.g., soft fillers (e.g., uncalcined talc), naturally occurring minerals (e.g., aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesia, silica, alumina, aluminum silicates, and the like), calcined naturally occurring minerals (e.g., enstatite), synthetic fused minerals (e.g., cordierite), treated fillers (e.g. silane-treated minerals), organic polymers (e.g., polytetrafluoroethylene), hollow spheres, microspheres, powdered polymeric materials, and the like.

[0082] Exemplary fillers include talc, mica, calcium carbonate, calcium sulfate, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesia, silica, alumina, TiCh, aluminum silicate, aluminum-zirconium-silicate, cordierite, silane-treated mineral, polytetrafluoroethylene, polyphenylene sulfide, and the like.

[0083] Thermally conductive fillers contemplated for optional use in the practice of the present disclosure include, for example, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesia, silica, alumina, zirconium silicate, and the like. Preferably, the particle size of these fillers will be about 20 microns. If aluminum nitride is used as a filler, it is preferred that it is passivated via an adherent, conformal coating (e.g., silica, or the like). [0084] When fillers are present, the resin composition may contain up to about 75% by weight, or up to about 50% by weight, or up to about 25% by weight, or up to about 10% by weight of the filler, where the % by weight is based on the total weight of the resin composition.

[0085] In another embodiment, the resin composition may be dissolved or dispersed in an organic solvent to form a resin composition varnish. The amount of solvent is not limited, but typically is an amount sufficient to provide a concentration of solids in the solvent of at least about 30% by weight to no more than about 90% by weight solids, or between about 50%-85% by weight solids, or between about 55%-75% weight solids.

[0086] The organic solvent is not specifically limited and may be a ketone, an aromatic hydrocarbon, an ester, an amide or an alcohol. More specifically, examples of organic solvents which may be used include, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate, N-methylpyrrolidone formamide, N-methylformamide, N,N- dimethylacetamide, methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethylether, triethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and mixtures thereof.

[0087] The resin composition of the present disclosure may optionally include one or more additives such as flexibilizers, anti-oxidants, dyes, pigments, surfactants, defoamers, silane coupling agents, dispersing agents, thixotropic agents, processing aids, flow modifiers, cure accelerators, strength enhancers, toughening agents, UV protectors (especially UV blocking dyes appropriate to enable Automatic-Optical Inspection (AOI) of Circuitry), flame retardants and the like, as well as mixtures of any two or more thereof.

[0088] Flexibilizers (also called plasticizers) contemplated for use in certain embodiments of the present invention include compounds that reduce the brittleness of the formulation, such as, for example, branched polyalkanes or polysiloxanes that lower the glass transition temperature of the compositions. Such plasticizers include, for example, polyethers, polyesters, polythiols, polysulfides, polybutadienes such as those sold under the Poly BD® and RICON® brand names. Plasticizers, when employed, are typically present in the range of about 0.5% by weight up to about 30% by weight of the resin composition.

[0089] Anti-oxidants contemplated for use in the practice of the present invention include hindered phenols (e.g., BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole), TBHQ (tertiary-butyl hydroquinone), 2,2'-methylenebis(6-tertiarybutyl-p-cresol), and the like), hindered amines (e.g., diphenylamine, N,N'-bis(l,4-dimethylpentyl-p-phenylene diamine, N-(4-anilinophenyl)methacrylamide, 4,4'-bis(a,a- dimethylbenzyl)diphenylamine, and the like), phosphites, and the like. When used, the quantity of anti-oxidant typically falls in the range of about 100 up to 2000 ppm, relative to the weight of the resin composition.

[0090] Dyes contemplated for use in certain embodiments of the present disclosure include nigrosine, Orasol blue GN, phthalocyanines, fluorescent dyes (e.g., Fluoral green gold dye, and the like), and the like. When used, organic dyes in relatively low amounts (i.e., amounts less than about 0.2% by weight) provide contrast.

[0091] Pigments contemplated for use in certain embodiments of the present disclosure include any particulate material added solely for the purpose of imparting color to the formulation, e.g., carbon black, metal oxides (e.g., Fe20s, titanium oxide), and the like. When present, pigments are typically present in the range of about 0.5% by weight up to about 5% by weight, relative to the weight of the resin composition.

[0092] Toughening agents contemplated for use in the practice of the disclosure are materials which impart enhanced impact resistance to various articles. Exemplary toughening agents include synthetic rubber containing compounds such as Hypro, Hypox, and the like.

[0093] UV protectors contemplated for use in certain embodiments of the present invention include compounds which absorb incident ultraviolet (UV) radiation, thereby reducing the negative effects of such exposure on the resin or polymer system to which the protector has been added. Exemplary UV protectors include bis(l,2,2,6,6-pentamethyl-4- piperidinyl) sebacate, silicon, powdered metallic compounds, hindered amines (known in the art as “HALS”), and the like.

[0094] Defoamers contemplated for use in certain embodiments of the present invention include materials which inhibit formation of foam or bubbles when a liquid solution is agitated or sheared during processing. Exemplary defoamers contemplated for use herein include n-butyl alcohol, silicon-containing anti-foam agents, and the like.

[0095] Exemplary silane coupling agents contemplated for use in the practice of the present invention include materials which form a bridge between inorganic surfaces and reactive polymeric components, including materials such as epoxy silanes, amino silanes, and the like.

[0096] Exemplary thixotropic agents contemplated for use in the practice of the present invention include materials which cause liquids to have the property of enhanced flow when shear is applied, including materials such as high surface area fillers (e.g., fumed silica) having particle sizes in the range about 2-3 microns, or even submicron size.

[0097] The resin composition of the present disclosure may be prepared by appropriately mixing the above components and also kneading or mixing, as needed, by a kneading means such as a 3 rolls mill, a ball mill, a bead mill or a sand mill, or a stirring means such as a high-speed rotary mixer, a super mixer or a planetary mixer. Further, by adding one or a mixture of the above-mentioned organic solvents, a resin composition varnish can also be prepared as described above. The amount of solvent is not limited, but typically is used in an amount sufficient to provide a concentration of solids in the solvent of at least 30% by weight to no more than 90% by weight solids, or between about 50%-85% by weight solids, or between about 55%-75% weight solids.

[0098] Curing

[0099] In accordance with yet another embodiment of the present disclosure, there are provided articles comprising a partially or fully cured layer of the above-described resin composition. According to one favorite embodiment, the provided articles comprise a partially or fully cured layer of the above-described resin composition on a substrate.

[0100] When the resin is cured by heat, the curing temperature differs according to the resin composition and the type and amount of the curing agent used. Generally, the curing temperature ranges from about 20°C to about 250°C, preferably from about 50°C to about 250°C.

[0101] Applications [0102] In accordance with yet another embodiment of the present disclosure, there are provided articles comprising a partially or fully cured layer of the above-described composition, preferably in association with a substrate.

[0103] The cured article can be suitably used in organic insulating materials, etc. for use in electronic equipment such as communications equipment, especially for manufacturing a high-frequency laminate.

[0104] The selection of the diamines (II) and (III), the dianhydride (IV), their ratios and the selection of parameters that result in the bi smal eimide compounds of formula (I) provide resin compositions with improved properties with regards to processing, dielectric properties, thermomechanical properties, and reduced water sensitivity.

[0105] The invention relates to a method for manufacturing an article, said method comprising at least the steps of preparing a curable resin composition as above disclosed, shaping the composition and curing the composition.

[0106] Shaping includes structuring the composition by giving it the expected shape, and/or associating the composition with another material, for example a support material, also designated as substrate or supporting article. Shaping may include a step of dissolving the resin composition in a solvent. Here-under are detailed several variants of the method according to the invention for manufacturing an article:

[0107] The present invention further concerns a process for manufacturing an article, for example a high-frequency laminate, comprising at least the following steps:

- Step 1 : Preparing a curable resin composition as above disclosed,

- Step 2: Dissolving the curable resin composition of step 1 in a solvent to form a varnish and applying the varnish to a supporting article,

- Step 3 : Curing the composition.

[0108] Applying the varnish to a supporting article can be implemented by any method known to the skilled professional, like for example, brush-painting the curable resin composition on the supporting article, spraying the curable resin composition on the supporting article, or spin-coating the curable resin composition on the supporting article. [0109] The present invention further concerns a process for manufacturing an article, especially a high-frequency laminate, comprising at least the following steps:

- Step 1 : Preparing a curable resin composition as above disclosed, - Step 2: Impregnating a support material, especially a fiber material with the composition of step 1,

- Step 3 : Curing the composition.

[0110] Impregnating a fiber material with the curable resin composition can be implemented by any method known to the skilled professional, like for example, dipping the fiber material in a solution of the curable resin composition, or spraying the curable resin composition on the fiber material, or spin-coating the curable resin composition on the fiber material. Such a method may require dissolving the curable resin composition in a solvent to form a varnish.

[0111] The present invention further concerns a process for manufacturing an article, comprising at least the following steps:

- Step 1 : Preparing a curable resin composition as above disclosed,

- Step 2: Introducing the composition of step 1 into a mold,

- Step 3 : Partially or fully curing the composition.

[0112] The present invention also relates to an article obtained by a method comprising at least a step of curing a composition according to the invention.

[0113] The compositions of the present invention enable to provide articles which can be used in a variety of applications, such as prepregs, metal clad laminates (e.g. copper clad laminates), printed circuit boards, light emitting diodes and electronic coatings.

[0114] Especially, the present invention relates to a prepreg obtained by impregnating a fiber material with a curable resin composition according to the invention and curing said resin.

[0115] The present invention also provides a laminated sheet, which can be used as high- frequency laminate, wherein said laminated sheet comprises the prepreg as defined above and a layer of an electrically conductive material disposed on at least one surface of the prepreg.

[0116] The invention is also directed to a printed wiring board produced by forming a conductive pattern on the surface of the laminated sheet as defined hereinabove.

[0117] As readily recognized by those of skill in the art, a variety of substrates are suitable for use in the practice of the present disclosure, for example, polyesters, liquid crystalline polymers, polyamides (e.g., Aramids), polyimides, polyamide-imides, polyolefins, polyphenylene oxides, polyphenylene sulfides, polybenzoxazines, conductive materials (e.g., conductive metals), and the like, as well as combinations of any two or more thereof. When conductive metal substrates are employed, such materials as silver, nickel, gold, cobalt, copper, aluminum, alloys of such metals, and the like, are contemplated for use herein.

[0118] In accordance with still another embodiment of the present disclosure, there are provided methods of making the above-described articles (i.e., articles comprising the composition according to the present disclosure on a substrate/supporting article), said methods comprising applying the resin composition to a substrate and, if an organic solvent is optionally employed to facilitate such application, removing substantially all organic solvent therefrom. The resin composition may be applied to the substrate by dipping, impregnating, spraying and the like.

[0119] In accordance with yet another embodiment of the present disclosure, there are provided prepregs produced by impregnating a porous substrate with a resin composition according to the present disclosure, and, if an organic solvent is optionally employed to facilitate such impregnation, subjecting the resulting impregnated substrate to conditions suitable to remove substantially all of the organic solvent therefrom.

[0120] As readily recognized by those of skill in the art, a variety of porous substrates can be employed for the preparation of inventive prepregs. The porous substrate may be woven or non-woven. The thickness of such substrate is not particularly limited, and may range, for example, from about 0.01 mm to 0.3 mm.

[0121] Examples of porous substrates can include, but are not limited to, woven glass, nonwoven glass, woven aramid fibers, non-woven aramid fibers, woven liquid crystal polymer fibers, non-woven liquid crystal polymer fibers, woven synthetic polymer fibers, nonwoven synthetic polymer fibers, randomly dispersed fiber reinforcements, expanded polytetrafluoroethylene (PTFE) structures and combinations of any two or more thereof. Specifically, materials contemplated for use as the porous substrate can include, but are not limited to, fiberglass, quartz, polyester fiber, polyamide fiber, polyphenylene sulfide fiber, polyetherimide fiber, cyclic olefin copolymer fiber, polyalkylene fiber, liquid crystalline polymer, poly(p-phenylene-2,6-benzobisoxazole), copolymers of polytetrafluoroethylene and perfluoromethylvinyl ether (MFA) and combinations of any two or more thereof. [0122] In accordance with still another embodiment of the present disclosure, there are provided laminated sheets produced by layering and molding a prescribed number of sheets of the above-described prepreg.

[0123] Laminated sheets according to the present disclosure have many particularly beneficial properties, such as, for example, low dielectric constant, low dissipation factor, high thermal decomposition temperature, and the like. In a preferred embodiment, laminated sheets according to the present disclosure have a dielectric constant ^4.0 nominal and a dissipation factor ^0.004 at 10 GHz, and a glass transition temperature of at least 100°C, or better at least 150°C, even better at least 200°C.

[0124] In one aspect of the present disclosure, laminated sheets as described herein may optionally further comprise one or more conductive layers. Such optional conductive layers are selected from the group consisting of metal foils, metal plates, electrically conductive polymeric layers, and the like. In one embodiment, the metal may be copper, silver, nickel, gold, cobalt, aluminum and alloys of such metals.

[0125] In another embodiment, there is provided a method of forming a laminated sheet. The method includes contacting the porous substrate with a varnish bath comprising the resin composition of the present disclosure dissolved and intimately admixed in a solvent or a mixture of solvents. The contacting occurs under conditions such that the porous substrate is coated with the resin composition. Thereafter the coated porous substrate is passed through a heated zone at a temperature sufficient to cause the solvent to evaporate, but below the temperature at which the resin composition undergoes significant cure during the residence time in the heated zone to form a prepreg.

[0126] The porous substrate preferably has a residence time in the bath of from about 1 second to about 300 seconds, more preferably from about 1 second to about 120 seconds, and most preferably from about 1 second to about 30 seconds. The temperature of such bath is preferably from about 0°C to about 100°C, more preferably from about 10°C to about 40°C, and most preferably from about 15°C to about 30°C. The residence time of the coated porous substrate in the heated zone is from about 0.1 minute to about 15 minutes, more preferably from about 0.5 minute to about 10 minutes, and most preferably from about 1 minute to about 5 minutes. [0127] The temperature of such zone is sufficient to cause any solvents remaining to volatilize away yet not so high as to result in a complete curing of the components during the residence time. Preferable temperatures of such zone are from about 80°C to about 250°C, more preferably from about 100°C to about 225°C, and most preferably from about 150°C to about 210°C. Preferably there is a means in the heated zone to remove the solvent, either by passing an inert gas through the oven, or drawing a slight vacuum on the oven. In many embodiments the coated substrate is exposed to zones of increasing temperature. The first zones are designed to cause the solvent to volatilize so it can be removed. The later zones are designed to result in partial cure of the resin composition (B- staging).

[0128] One or more sheets of prepreg are preferably processed into laminates optionally with one or more sheets of electrically-conductive material such as copper. In such further processing, one or more segments or parts of the coated porous substrate are brought in contact with one another and/or the conductive material. Thereafter, the contacted parts are exposed to elevated pressures and temperatures sufficient to cause the components to cure wherein the resin on adjacent parts react to form a continuous resin matrix between the porous substrates. Before being cured the parts may be cut and stacked or folded and stacked into a part of desired shape and thickness. The pressures used can be anywhere from about 1 psi to about 1000 psi with from about 10 psi to about 800 psi being preferred. The temperature used to cure the resin composition in the parts or laminates, depends upon the particular residence time, pressure used, and components used. Preferred temperatures which may be used are between about 100°C and about 250°C, more preferably between about 120°C and about 220°C, and most preferably between about 170°C and about 200°C. The residence times are preferably from 10 minutes to 120 minutes and more preferably from about 20 minutes to about 90 minutes.

[0129] In one embodiment, the process is a continuous process where the porous substrate is taken from the oven and appropriately arranged into the desired shape and thickness and pressed at very high temperatures for short times. In particular such high temperatures are from about 180°C to about 250°C, more preferably about 190°C to about 210 C, at times of about 1 minute to about 10 minutes and from about 2 minutes to about 5 minutes. Such high speed pressing allows for the more efficient utilization of processing equipment. In such embodiments the preferred reinforcing material is a glass web or woven cloth.

[0130] In some embodiments it is desirable to subject the laminate or final product to a post cure outside of the press. This step is designed to complete the curing reaction. The post cure is usually performed at from about 130°C to about 220°C for a time period of from about 20 minutes to about 200 minutes. This post cure step may be performed in a vacuum to remove any components which may volatilize.

[0131] Thus, in accordance with yet another embodiment of the present disclosure, there are provided methods of making a laminated sheet, said method comprising layering and molding a prescribed number of sheets of a prepreg according to the present disclosure.

[0132] In accordance with a further embodiment of the present disclosure, there are provided printed wiring boards produced by forming conductive patterns on the surface of the above-described laminated sheet(s). Forming the conductive patterns may can be carried out by, for example, forming a resist pattern on the surface of the laminated sheet(s), removing unnecessary portions of the sheet by etching, removing the resist pattern, forming the required through holes by drilling, again forming the resist pattern, plating to connect the through holes, and finally removing the resist pattern.

[0133] In accordance with a still further embodiment of the present disclosure, there are provided multilayer printed wiring boards produced by layering and molding a prescribed number of sheets of the above-described patterned laminate layers, bonded together with one or more layers of prepreg from which the printed wiring board layer was prepared.

[0134] In accordance with a still further embodiment of the present invention, there are provided methods of making printed wiring boards, said methods comprising forming conductive patterns on the surface of a laminated sheet according to the present disclosure. [0135] In accordance with yet another embodiment of the present disclosure, there are provided multilayer printed wiring boards produced by layering and molding a prescribed number of sheets of the above-described prepreg, to obtain a printed wiring board for an inner layer, and layering the prepreg on the printed wiring board for an inner layer which forms conductive patterns on the surface.

[0136] Accordingly, the prepreg and the printed wiring boards of the present disclosure may be usefully used as a component of a printed circuit board for a network for use in various electrical and electronic devices such as mobile communication devices that handle a high frequency signal of GHz or more, or the base station device thereof, and network- related electronic devices such as servers and routers, and large computers.

[0137] In some embodiments, the resin compositions of the present invention may have a dielectric dissipation factor (Df) that is flat over a wide frequency range, such that a component fabricated therefrom can operate efficiently at several different processing speeds. This is important because many state of the art electronic devices can operate over a range of frequencies and it is therefore desired that the electronic components maintain proper function throughout this frequency range.

[0138] It has been discovered that using the present composition of the invention enables to reach ultra-low loss factor Df in the gigahertz range (e.g., 1-10 GHz, below 0.005 at 10 GHz), which is unexpected in view of the prior art.

[0139] Specifically, the curable resin compositions according to the invention give access, after curing, to articles having a dielectric dissipation factor (Df) measured on a Split Post Dielectric Resonator (SPDR) at a frequency of 10 GHz below 0.005, preferably below 0.004, more preferably below 0.0035.

[0140] According to a favorite embodiment, the articles resulting from curing compositions of the present disclosure have a dielectric constant (Dk) at 10 GHz of less than about 4 or less than about 3.5.

[0141] Specifically, the curable resin compositions according to the invention give access, after curing, to articles having a Tg superior or equal to about 100°C, preferably superior or equal to about 150°C, more preferably superior to about 200°C.

[0100] The present disclosure will now be further described with reference to the following non-limiting examples.

Examples

[0101] Materials:

Priamine 1075 ®: an aliphatic C36 dimer diamine commercialized by CRODA

DAPI: an aromatic amine (Diamino-l,3,3-trimethyl-l-phenylindane) commercialized by HUNTSMAN.Pyromellitic Dianhydride is commercialized by CABB Group (ex JAYHAWK).

[0102] Example 1 - Preparation of bismal eimide compounds [0103] Example la - Preparation of bismaleimide compound according to the invention: A 2L reaction flask equipped with stirrer and a dean-stark trap was charged with 0.2734 moles of Pyromellitic Dianhydride in 550ml Toluene and 220ml N-methyl pyrollidone, and the mixture was heated to 90-95°C. 0.082 moles of Priamine 1075 ® in 120ml of toluene was introduced and reacted for 20minutes under reflux conditions. 0.328 moles of 4',5-6-Diamino-l,3,3-trimethyl-l-phenylindane (DAPI) in 110ml of Toluene and 130ml of N-methyl pyrollidone was introduced. The temperature was increased to 125°C and reacted for 2hrs under reflux conditions. The reaction mixture was cooled to 100°C and 0.3034 moles of maleic anhydride and 0.0802 moles of p-toluene sulfonic acid monohydrate was introduced. The temperature was increased to 125°C and the reaction was continued for 5hrs under reflux conditions. The solution was washed with brine and the toluene removed under vacuum. The solid is then purified by dissolving in N-methyl pyrrolidone followed by precipitation in methanol and vacuum drying. Mass yield is 70%. Analytics performed are 1H, 1C NMR, HPLC, GC, and GPC and confirm the structure of expected products in the reaction mixture.

[0104] Example lb - Preparation of comparative bismaleimide compound: follow example la protocol where Priamine 1075 ® is replaced by DAPI.

[0105] Example 1c - Preparation of comparative bismaleimide compound: follow example la protocol where DAPI is replaced by Priamine 1075 ®.

[0106] Example 2 - Preparation of inventive and comparative resin compositions Components identified in Table 1 were dissolved at room temperature in toluene to produce a homogenous resin composition varnish with a concentration of 50-60% by weight solids (compositions Cla, Clb and Clc).

Table 1

[0107] Example 3 - Application - preparation of prepregs and laminates

Glass fabric (E2116NE glass) was immersed into the varnish, then placed vertical in an oven and dried for 2 minutes at 140°C to produce sheets of prepreg.

The sheets of prepreg above were press cured for 2 hours at 220°C with a resin content of about 45% by weight to about 50% by weight in the final laminate.

The resulting laminates with an approximate thickness of 0.5 mm were evaluated for the dielectric constant (Dk) and the dissipation factor (Df) on a Split Post Dielectric Resonator (SPDR) at a frequency of lOGhz and Glass transition was measured in oscillation mode at Ihz from 23 °C to 300°C at 2°C/min. The glass transition was determined by the G’ onset and tan delta as the maxima.

Table 2

[0108] The result show clearly the effect of utilising a mixture of the aromatic and aliphatic amines. The fully aromatic bismaleimide (Comp Ex. lb) dielectric loss is significantly increased compared to Ex. la, whereas the aliphatic amine based bismaleimide (Comp. Ex.1c) has a glass transition significantly lower than the Ex. la.

[0109] Although making and using various embodiments of the present invention have been described in detail above, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.

Claims

1. Bismaleimide compounds of formula (I):

Formula (I)

Wherein n is an integer, n ranges from 1 to 10, m is an integer, m ranges from 1 to 10, each Q, independently, is a tetravalent radical selected from C6-C50 hydrocarbons comprising at least one aromatic group and optionally one or more heteroatoms selected from O, N, S, F, Cl, Br, each Rl, independently, is a divalent radical selected from aliphatic and aromatic, linear or branched, C1-C60 hydrocarbyls, optionally comprising one or more NH2 group, one or more NH bridges, each R2, independently, is a divalent radical selected from C6-C54 aromatic hydrocarbons, optionally comprising one or more halogen atoms,

R is a divalent radical Rl or R2,

Y represents H or CH3.

2. Bismaleimide compounds according to claim 1, wherein Q is selected from the structures:

with Q’ a divalent radical that selected from C1-C38 hydrocarbons optionally comprising one or more heteroatoms selected from O, N, S, F, Cl, and Br.

3. Bismal eimide compounds according to claim 1 or claim 2, wherein each R1 is, independently, selected from C12-C60 alkyl, alkenyl or aralkyl, optionally comprising one or more NH2 group, one or more NH bridges.

4. Bismaleimide compounds according to any one of claims 1 to 3, wherein each R2, independently, is selected from divalent radicals of the formula (IIIA)

Formula (I HA)

Wherein

Yl, Y2, independently, represent H, a C1-C5 alkyl,

Each Y3, Y4, independently, represents H, a halogen, a C1-C4 alkyl.

5. A method for the preparation of bismal eimide compounds as described in any one of claims 1 to 4, said method comprising the following steps:

Formula (I)

• Step 1 : Reacting a dianhydride (IV) with a diamine of the formula (II) and a diamine of the formula (III) to obtain an amine terminated extended imide (V), • Step 2: Reacting the amine terminated extended imide (V) resulting from step 1 with a maleic anhydride compound (VI),

Wherein n, m, Q, Rl, R2, R and Y have the same definition as in formula (I),

An and Am, respectively, represent the relative molar amount of the diamine H2N-RI- NH2 and the diamine H2N-R2-NH2 introduced in the reaction medium with regards to the amount of dianhydride (IV).

6. The method as claimed in claim 5, wherein the ratio of the sum of amounts of amines (Am + An) to dianhydride compound ranges from about 5: 1 to about 1.05: 1.

7. The method as claimed in claim 5 or claim 6, wherein the molar ratio Am / An, of aromatic amine(s) (III) to aliphatic amine(s) (II), ranges from about 20: 1 to about 1 : 1, more preferably from about 10 : 1 to about 2: 1, even more preferably from about 5 : 1 to about 3: 1, advantageously about 4: 1.

8. The method as claimed in any one of claims 5 to 7, wherein the first step of the method proceeds in two sub-steps:

• Sub-step 1 a: the reaction of the dianhydride (IV) with the aliphatic diamine of formula H2N-RI-NH2 (II),

• Sub-step 1 b: the reaction of the product resulting from Sub-step 1 a with the aromatic diamine H2N-R2-NH2, resulting in an amine terminated extended imide (V).

9. The method as claimed in any one of claims 5 to 8, wherein said method is implemented in one pot.

10. A bismaleamide compound produced by the method of any one of claims 5 to 9.

11. A curable resin composition comprising at least a bismaleimide compound of formula

(I) as claimed in any one of claims 1 to 4 or in claim 10 and at least one co-curing agent.

12. A curable resin composition according to claim 11, wherein the co-curing agent is selected from polyphenylene ether derivatives, maleimides, styrenes, divinylbenzenes, trivinylcyclohexanes, trialkenyl isocyanurate compounds and mixtures thereof, preferably trialkenyl isocyanurate compounds such as triallyl isocyanurate.

13. A curable resin composition according to claim 11 or claim 12, wherein the bismaleamide compound represents from about 20 to about 99%, more preferably from about 30 to about 98% by weight of the total weight of the resin composition and the cocuring agent represents from about 1% to about 50%, preferably from about 2% to about 20%, by weight based on the total weight of the composition.

14. A process for manufacturing an article, comprising at least the following steps:

- Step 1 :

Preparing a curable resin composition as claimed in any one of claims 11 to claim 13,

- Step 2:

Shaping the composition,

- Step 3 :

Partially or fully curing the composition.

15. An article produced by the method of claim 14.

16. Article according to claim 15, having a dielectric dissipation factor (Df) measured on a Split Post Dielectric Resonator (SPDR) at a frequency of 10 GHz below 0.005, preferably below 0.004, more preferably below 0.0035, a dielectric constant (Dk) at 10 GHz of less than about 4 or less than about 3.5 and a Tg superior or equal to 100°C, preferably superior or equal to 150°C, more preferably superior to 200°C.

17. An article according to claim 15 or claim 16, which is a prepreg obtained by impregnating a fiber material with a composition according to any one of the claims 1 to 4 or 10.

18. A laminate comprising the prepreg of claim 17 and a layer of an electrically conductive material disposed on at least one surface of the prepreg.

19. A printed wiring board produced by forming a conductive pattern on the surface of the laminate of claim 18.

20. Use of the resin composition as claimed in any one of claim 1 to claim 4 and claim 10, in a prepreg, a metal clad laminate, a printed circuit board, a light emitting diode, an electronic coating, a textile, a polymer molding compound, a medical molding compound and an adhesive.