Bismaleimide compound and low dielectric constant resin composition containing bismaleimide compound

Abstract

A bismaleimide compound of general formula (I): wherein R1 is a divalent aliphatic group and R2 is a divalent aromatic group; and a resin composition comprising the bismaleimide compound of general formula (I), having a low dielectric constant (Dk), a low dielectric loss factor (Df), and a high glass transition temperature (Tg).

Description

TECHNICAL FIELD

[0001] The present invention relates to novel bismaleimide compounds, resin compositions comprising the compounds, methods for their preparation and their use in various applications, for example in the production of prepregs, laminates for printed wiring boards, molding materials and adhesives. The resin compositions provide cured products having high heat resistance, low water absorption and excellent dielectric properties. These advantageous properties are required for organic insulating materials for electronic devices such as communication equipment. BACKGROUND

[0002] With the development of wireless networks and satellite communications, electronic products increasingly require higher speed, frequency and greater capacity to transmit sound, video and data. In addition, as these electronic products become thinner and smaller, the complexity, density and multi-layering of circuit boards tend to increase. In order to maintain high transmission rates and signal integrity, printed circuit boards ("PCBs") need to have materials with low dielectric constant (D k ) and low dielectric loss (sometimes also referred to as loss tangent or dissipation factor D f ) to reduce signal loss.

[0003] Polymeric insulating materials are generally used as base material for PCBs. The laminating material of the PCB is either made solely of a polymeric insulating material or by mixing a polymeric insulating material with glass, fiber, nonwoven fabric, inorganic filler, etc. Traditionally, epoxy resins have been adopted due to their low cost and high heat and chemical resistance after curing. However, it is difficult to achieve a suitable low dissipation factor at high frequency signals due to their relatively high dielectric constant and high dielectric loss tangent. Polyphenylene oxide (PPO) resins are also used for laminating materials due to their lower dielectric constant and dissipation properties, but lower dielectric loss constant and dissipation factor are required for the use of high frequency signals in new electronic fields. Fluororesins, typically represented by polytetrafluoroethylene (PTFE), have a lower dielectric constant and dissipation factor, but they are thermoplastic resins, thus they are materials that are not easy to handle due to large expansion and contraction during molding and processing.

[0004] Other types of resins are known, but cannot achieve low dielectric loss values D f , which are necessary from the viewpoint of high frequency signal transmission requirements.

[0005] Bismaleimide compounds are known in the formulation of electronic materials:

[0006] EP 3135722 discloses a heat-curable resin composition for the electrical and electronic industry, which is suitable for use in underfilling and for performing potting. The heat-curable resin composition comprises a heat-curable resin and a bismaleimide compound in liquid form at 25°C.

[0007] US 7884174 discloses imide extended mono, bis or poly-maleimide compounds and their use in the preparation of thermosetting adhesive compositions useful for various applications in the manufacture and assembly of semiconductor packages and microelectronic devices.

[0008] US 3856752 discloses aromatic polyimides having improved solubility in polar organic solvents and their use as adhesives, laminating resins, especially for printed circuit boards, fibers, coatings, decorative and electrical applications, films, enameled wires and molding compounds.

[0009] However, the prior art bis-maleimide and aromatic polyimide compounds have drawbacks due to limited solubility and humidity sensitivity.

[0010] There is still a need for a resin composition that can be used in electronic devices and provides a higher dissipation factor and / or a higher decomposition temperature.

[0011] There is still a need to provide a curable bis-maleimide compound to obtain a resin composition with improved properties, especially in terms of D f , thermodynamic properties, humidity resistance, and can be easily processed. There is a need to improve high frequency signal transmission while reducing power and interference problems in electronic applications. This requires a material composition with improved dielectric properties while ensuring the required thermodynamic properties and ease of manufacture for mass sustainable production of printed circuit boards and antennas.

[0012] It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art resin compositions and to provide an improved polymeric insulating material having sufficient thermodynamic properties, humidity resistance, low dielectric properties and ease of processing to cope with the increasing high frequency signal transmission. SUMMARY

[0013] The present invention relates to a new bis-maleimide compound of the following general formula (I):

[0014]

[0015] wherein

[0016] n is an integer, n ranges from 1 to 10,

[0017] m is an integer, m ranges from 1 to 10,

[0018] each Q is independently a tetravalent group selected from C6-C50 hydrocarbon comprising at least one aryl group and optionally one or more heteroatoms selected from O, N, S, F, CI, Br,

[0019] each R1 is independently a divalent group selected from linear or branched C1-C60 hydrocarbons, aliphatic and aromatic, which optionally comprises one or more NH2 groups or one or more NH bridges,

[0020] each R2 is independently a divalent group selected from C6-C54 arenes, which optionally comprises one or more halogen atoms,

[0021] R is a divalent group selected from R1 and R2,

[0022] each Y is independently H or CH3.

[0023] The present application also relates to a new bismaleimide compound obtained from a process comprising the steps of:

[0024]

[0025] Step 1 : reacting a dianhydride (IV) with a diamine of general formula (II) and a diamine of general formula (III) to obtain an amine-terminated extended imide (V),

[0026] Step 2: reacting the amine-terminated extended imide (V) obtained in Step 1 with a maleic anhydride compound (VI),

[0027] wherein n, m, Q, R1, R2, R and Y are the same as defined in general formula (I) above, An and Am represent the relative molar amounts of diamine H2N-R1-NH2 and diamine H2N-R2-NH2, respectively, introduced into the reaction medium with respect to the amount of dianhydride (IV).

[0028] The present application also relates to a curable resin composition comprising at least one bismaleimide compound as described above and at least one heat-curable resin.

[0029] The present application also relates to a method of producing an article, said method comprising at least the steps of:

[0030] - Step 1 :

[0031] preparing a curable resin composition comprising at least a bismaleimide compound as described above and a heat-curable resin,

[0032] - Step 2:

[0033] shaping said composition,

[0034] - Step 3:

[0035] partially or totally curing said composition.

[0036] The present application also relates to articles obtained from the described methods, including cured resins, sheet cured resins, laminates, prepregs, electronic components and single and multi-layered circuit boards comprising the resin composition of the present application.

[0037] The present application also relates to the use of the described resin composition in prepregs, metal clad laminates, printed circuit boards, light emitting diodes, electronic coatings, textiles, polymer molding compounds, medical molding compounds and adhesives.

[0038] The bismaleimide compounds of the present application show an optimized performance between thermodynamic (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, while having processing characteristics suitable for electronic material formulations, thereby improving dielectric and thermodynamic properties. DETAILED DESCRIPTION

[0039] The present application generally relates to a new bismaleimide compound and a resin composition obtained from these new bismaleimide compounds, said resin having a low dielectric constant (D k ), a low dielectric loss factor (D f ) and excellent thermodynamic properties, such as high thermal stability, good processability, high peel strength, good moisture resistance and / or high glass transition temperature (Tg). In an attempt to achieve the objectives of the present application, it was surprisingly found that when a resin composition is prepared with the above described bismaleimide compound, the D f can be significantly reduced, while having a higher Tg, compared to resin compositions containing prior art resins. This new resin composition generally exhibits a low D k and a low D f (usually D f <0.003) in the gigahertz range (e.g. 1-10 GHz), enabling it to meet the stringent industry standards required in various applications such as prepregs, metal clad laminates, printed circuit boards, light emitting diodes and electronic coatings. It shows high thermodynamic properties (high Tg) and high solubility (> 50 wt% in typical CCL (copper clad laminate) solvents such as toluene, MEK).

[0040] The new bismaleimide compounds and resin compositions can also be used in chip design (integrated circuit (IC) packaging), coatings, chemical vapor deposition (CVD) and photochemistry. In addition, they can be used to prepare films, filters and high performance coatings, fiber reinforced composites and adhesives. The new bismaleimide compounds can also be used as intermediates for radical and polycondensation formulations.

[0041] The following terms shall have the following meanings:

[0042] The term "comprising," along with its derivatives, as used in connection with this disclosure are used to mean including, without necessarily excluding, some further component, step or procedure. For the avoidance of doubt, the term "comprising" is taken to mean the inclusion of an item or items or process steps or process steps, but not to the exclusion of any additional, non specified, item, process step or process steps. In other words, the indefinite articles "a" or "an" preceding the use of "comprising" should be understood to mean one or more, i.e. at least one, of the components, steps or processes. Conversely, the term "consisting essentially of shall exclude any components, steps or processes not specifically recited, while the term "consisting of shall exclude any components, steps or processes other than those specifically recited. The term "or" as used in the context of this disclosure should be understood as not requiring mutual exclusivity, unless otherwise stated.

[0043] As used herein, the indefinite articles "a" or "an" preceding the use of "comprising" should be understood to mean one or more, i.e. at least one, of the components, steps or processes. Conversely, the term "consisting essentially of shall exclude any components, steps or processes not specifically recited, while the term "consisting of shall exclude any components, steps or processes other than those specifically recited. The term "or" as used in the context of this disclosure should be understood as not requiring mutual exclusivity, unless otherwise stated.

[0044] As used herein, the term "about" can allow for a degree of variability in a value or range, for example, said value or range being within 10%, within 5%, or within 1% of a stated value or range.

[0045] Numerical 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 also to include all the individual numerical values or sub-ranges within the indicated range. For example, a range of "1 to 6" should be interpreted to include not only the explicitly recited values of 1 to 6, but also include individual values and sub-ranges within the indicated range, for example, 1, 2, 3, 4, 5, and 6, as well as sub-ranges such as 1-2, 2-4, 3-6, etc. This same principle applies to ranges reciting only end points, for example, "at least 1" should be interpreted to include not only the explicitly recited value of 1, but also to include sub-ranges such as 1-3, 2-4, etc.

[0046] The terms "preferably," "preferred," "prefer," "preferable," and words of similar meaning in the context of this disclosure are used to indicate that a recited embodiment is, for certain reasons, advantageous. However, the use of such terms is not intended to mean that the embodiments described therein are the only way(s) to solve the problem recited, and in fact, many non-recited embodiments could also solve the same problem. Additionally, the use of these terms is not intended to necessarily exclude other embodiments that are not recited.

[0047] The terms "in a range" or "within a range" (and similar statements) include the range endpoints.

[0048] When substituent groups are specified by their conventional chemical formulae, written from left to right, they likewise encompass the same substituents written in the opposite direction, e.g., -CH2O- is equivalent to -OCH2-.

[0049] The terms "optional" or "optionally" mean that the subsequently described event or circumstance can or can not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0050] The term "alkyl" means a straight or branched chain hydrocarbon having from 1 to 50 carbon atoms, while "substituted alkyl" means an alkyl group further bearing one or more substituents selected from, but not limited to, hydroxy, alkoxy, thio, cycloalkyl, heterocyclyl, aryl, heteroaryl, aryloxy, halogen, trifluoromethyl, cyano, nitro, nitrone, amino, amido, C(O)H, acyl, oxyacyl, carboxyl, carbamate, sulfonyl, sulfonamide, and thioacyl.

[0051] The term "alkenyl" means a straight or branched chain hydrocarbon having from 2 to 50 carbon atoms and at least one carbon-carbon double bond.

[0052] The term "alkynyl" means a straight or branched chain hydrocarbon having from 2 to 50 carbon atoms and at least one carbon-carbon triple bond.

[0053] The term "aryl" means a hydrocarbon group which contains from 6 to 50 carbon atoms and which contains at least one ring having a delocalized pi electron system, such as a benzene ring.

[0054] The term "aralkyl" means any monovalent group derived from an alkyl group by the replacement of one or more of the hydrogen atoms with an aryl group.

[0055] The terms "dielectric loss factor (D f " and "loss tangent" are synonymous and refer to the amount of energy dissipated into an insulating material (i.e., electrical loss) when a voltage is applied to a circuit. f represents the loss of a signal in a circuit.

[0056] The terms "dielectric constant (D k " and "permittivity" are synonymous and refer to a measure of the relative capacitance of an insulating material compared to air or vacuum. The dielectric constant determines the speed of an electronic signal.

[0057] The term "glass transition temperature" or "Tg" as used herein means the temperature at which the amorphous domains of a polymer exhibit the characteristic properties of a glassy state, i.e., brittleness, rigidity, and hardness. The term further means the temperature at which a solidified resin transitions from a glassy state to a softer, more rubbery state.

[0058] Bismaleimide compounds

[0059] According to a first aspect, the present invention relates to novel bismaleimide compounds of the following general formula (I):

[0060]

[0061] in

[0062] n is an integer, the range of n is 1-10, and the range of n is preferably 1-5

[0063] m is an integer, the range of m is 1-10, and the range of m is preferably 1-5.

[0064] Each Q is independently a tetravalent group selected from C6-C50 hydrocarbons, which contains at least one aromatic group and optionally one or more heteroatoms selected from O, N, S, F, Cl, Br,

[0065] Each R1 is independently a divalent radical selected from aliphatic and aromatic linear or branched C1-C60 hydrocarbons, which optionally contains one or more NH2 groups and / or one or more NH bridges,

[0066] Each R2 is independently a divalent group selected from C6-C54 aromatic hydrocarbons, which optionally contain one or more halogen atoms,

[0067] R is a divalent group R1 or R2,

[0068] Y represents H or CH 3. Y is preferably H.

[0069] Q is a tetravalent group present in the aromatic dianhydride that has been reacted with the diamine H2N-R1-NH2 and the diamine H2N-R2-NH2.

[0070] As examples of groups Q, the following structures may be mentioned:

[0071]

[0072] Q' is a divalent group which may be selected from C1-C38 hydrocarbons optionally containing one or more heteroatoms selected from O, N, S, F, Cl, Br.

[0073] For example, Q′ can be -CO-, -CO-NH-, -CO-O-, -O-CO-O-, -NH-CO-NH-, a divalent C1-C40 alkyl group, a divalent C1-C40 alkenyl group, or a divalent C1-C40 alkynyl group, wherein the alkyl group, alkenyl group or alkynyl group optionally contains one or more -O- bridges, one or more -NH- bridges, one or more substituents selected from -OH, NH2, COOH, CONH2, -SH, -SO3H, or a halogen atom.

[0074] According to a most preferred embodiment, Q is selected from the following groups:

[0075]

[0076] Each R1is independently a divalent group selected from linear or branched C1-C60 hydrocarbons, aliphatic and aromatic, which optionally comprise one or more NH2groups, one or more NH bridges. Each R1is preferably independently a divalent group selected from C1-C60 alkyl, C2-C60 alkenyl, C2-C60 alkynyl, C6-C60 aralkyl, which optionally comprise one or more NH2groups, one or more NH bridges.

[0077] Each R1may be independently linear or branched.

[0078] Preferably, each R1is independently selected from C1-C60 alkyl, alkenyl or aralkyl, which optionally comprise one or more NH2groups, one or more NH bridges, preferably from C12-C60 alkyl, alkenyl or aralkyl, which optionally comprise one or more NH2groups, one or more NH bridges.

[0079] More preferably, each R1is independently selected from dimeric and trimeric hydrocarbyl groups having a total number of carbon atoms from 12 to 60 and mixtures thereof.

[0080] Preferably, R1is selected from linear, branched or cyclic alkyl or alkenyl groups or aromatic hydrocarbons having a total number of carbon atoms from 12 to 60 and mixtures thereof.

[0081] Each R2is independently a divalent group selected from aromatic C6-C54 hydrocarbons.

[0082] Preferably, R2is an aromatic C6-C54 divalent group comprising a phenyl indane group.

[0083] Preferably, R2is selected from divalent groups of general formula (IIIA):

[0084]

[0085] wherein

[0086] Y1, Y2independently represent H, C1-C5 alkyl,

[0087] Each Y3, Y4independently represents H, halogen, C1-C4 alkyl.

[0088] When Y3and / or Y4are halogen, they are preferably CI.

[0089] In general formula (IIIA), Y3and Y4are preferably both H.

[0090] In general formula (IIIA), Y1, Y2preferably independently represent H or methyl. According to one embodiment, Y1and Y2represent CH3.

[0091] In general formula (IIIA), the radical substituents are preferably located in the 5' or 6' and 4' positions.

[0092] Preparation of bismaleimide compounds

[0093] The present application also relates to the new bismaleimide compounds formed by a process comprising the steps of:

[0094]

[0095] • Step 1 : reacting a dianhydride (IV) with a diamine of general formula (II) and a diamine of general formula (III) to obtain an amine-terminated extended imide (V),

[0096] • Step 2: reacting the amine-terminated extended imide (V) obtained in Step 1 with a maleic anhydride compound (VI),

[0097] wherein n, m, Q, R1, R2, R and Y have the same definitions and preferred embodiments as in general formula (I) above, and An and Am represent the relative molar amounts of diamine H2N-R1-NH2(II) and diamine H2N-R2-NH2(III) introduced into the reaction medium relative to the amount of dianhydride (IV).

[0098] As examples of aromatic dianhydrides (IV), mention can be made of: pyromellitic dianhydride; 1,4,5,8-naphthalene-tetracarboxylic dianhydride; 2,3,6,7- naphthalene-tetracarboxylic dianhydride; 1,2,4,5-naphthalene-tetracarboxylic dianhydride; 1,2,5,6-naphthalene-tetracarboxylic dianhydride; benzene-1,2,3,4- tetracarboxylic dianhydride; pyrazine-2,3,5,6-tetracarboxylic dianhydride; thiophene-2,3,4,5-tetracarboxylic dianhydride; 3,4,9,10-perylene- tetracarboxylic dianhydride; 2,3,9,10-perylene-tetracarboxylic dianhydride; 2,6- dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride; 2,7-dichloronaphthalene- 1,4,5,8-tetracarboxylic dianhydride; 2,3,6,7-tetrachloronaphthalene-1,4,5,8- tetracarboxylic dianhydride; phenanthrene-1,8,9,10-tetracarboxylic dianhydride; 3,3',4,4'-benzophenone-tetracarboxylic dianhydride; 2,2',3,3'-benzophenone- tetracarboxylic dianhydride; 3,3',4,4'-biphenyl-tetracarboxylic dianhydride; 2,2',3,3'- biphenyl-tetracarboxylic dianhydride; 4,4'-oxydiphthalic anhydride; 3,3'- oxydiphthalic anhydride; 4,4'-isopropylidene diphthalic anhydride; 3,3'- isopropylidene diphthalic anhydride; 3,3',4,4'-diphenyl sulfone-tetracarboxylic dianhydride; 4,4'-sulfonyldiphthalic anhydride; 4,4'-methylene diphthalic anhydride; 4,4'-thio diphthalic anhydride; 4,4'-ethylene diphthalic anhydride; 2,2'-bis(3,4- dicarboxyphenyl)hexafluoropropane dianhydride; 4,4'-bisphenol A diphthalic anhydride, ethylene glycol bis(trimellitic anhydride); hydroquinone diphthalic anhydride.

[0099] According to a most preferred embodiment, the aromatic dianhydride (IV) is pyromellitic dianhydride or 3,3',4,4'-benzophenone-tetracarboxylic dianhydride.

[0100] Amines of general formula (II) are commercially available. Examples of diamines (II) (NH2-R1-NH2) that can be used in the application include: 1,10-decanediamine; 1,12-diaminododecane; 1,18-diamino-6,8-dialkylidene; dimer diamines C36-alkylidene diamines; trimer amines C54 trimer amines; 1,2-diamino-2-methylpropane; 1,2-diaminocyclohexane; 1,2-diaminopropane; 1,3-diaminopropane; 1,4-diaminobutane; 1,5-diaminopentane; 1,7-diaminoheptane; 1,8-diaminopinane; 1,8-diaminooctane; 1,9-diaminononane; 3,3'-diamino-N-methyldipropylamine; 1,3-diaminopentane; 1,3-diaminomethylcyclohexane; polyoxyalkylene diamines (such as Huntsman's Jeffamine D-230, D400, D-2000 and D-4000 products); 1,3-cyclohexanebis(methylamine); bis(4-amino-3-methylcyclohexyl)methane; 1,2-bis(2-aminoethoxy)ethane; 3(4),8(9)-bis(aminomethyl)tricyclo(5.2.1.0<2,6>)decane.

[0101] As examples of amines, mention can be made of the mixture of amines sold by Croda under the reference Priamine 1075 (mainly dimer amines) or Priamine 1071 (mixture comprising dimer amines C36 and trimer amines C54).

[0102] Other examples of amines derived from dimer fatty acids from which the radical R1 can be obtained are illustrated in the following diagram:

[0103]

[0104]

[0105] The diamine (II) NH2-R1-NH2 is preferably chosen from aliphatic C12-C60 dimer diamines, C12-C60 trimer triamines and mixtures thereof.

[0106] Examples of aromatic diamines (III) (NH2-R2-NH2) useful in the present application 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-methoxyfluorene; 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-isopropylidinediamine; 1,3-diaminomethylbenzene; 2-chloro-l,4-diaminobenzene; 1,4-diamino-2,5-dichlorobenzene; 1,4-diamino-2,5-dimethylbenzene; 4,4'-diamino-2,2'-bistrifluoromethylbiphenyl; bis(amino-3-chlorophenyl)ethane; bis(4-amino-3,5-dimethylphenyl)methane; bis(4-amino-3,5-diethylphenyl)methane; bis(4-amino-3-ethyldiaminofluorene; diaminobenzoic acid; 2,3-diaminonaphthalene; 2,3-diaminophenol; -5-methylphenyl)methane; bis(4-amino-3-methylphenyl)methane; bis(4-amino-3-ethylphenyl)methane; 4,4'-diaminophenyl sulfone; 3,3'-diaminophenyl sulfone; 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'-oxydianiline; 2,2-bis(4-(4-aminophenoxy)phenyl)propane; 1,3-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-bisaniline sulfone; methylenebis(o-aminobenzoic acid); 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane; 1,3-bis(4-aminophenoxy)propane; 1,4-bis(4-aminophenoxy)butane; 1,5-bis(4-aminophenoxy)butane; 2,3,5,6-tetramethyl-l,4-phenylene diamine; 3,3',5,5'-tetramethylbenzidine; 4,4'-diaminophenyl benzamide; 2,2-bis(4-aminophenyl)hexafluoropropane; m-xylylenediamine; p-xylylenediamine.

[0107] Some phenylindane amines are commercially available. Others can be prepared by the method disclosed in US 3,856,752, the content of which is incorporated herein by reference.

[0108] The diamine (III) NH2-R2-NH2is preferably selected from DAPI (4',5-6-diamino-1,3,3-trimethyl-1 -phenylindane).

[0109] According to the application, the ratio of the sum of amines (Am + An) to the dianhydride compound is preferably 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, the ratio is about 1.5:1.

[0110] According to the application, the molar ratio of aromatic amine to aliphatic amine Am / An is preferably 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.

[0111] The maleic anhydride compound (VI) is preferably maleic anhydride.

[0112] The amount of maleic anhydride compound is chosen so as to obtain a product which is terminated at both ends by maleimide groups.

[0113] According to a preferred embodiment, the first step of the process for preparing the bismaleimide compound of general formula (I) is carried out in two sub-steps:

[0114] Sub-step 1 a: reacting the dianhydride (IV) with an aliphatic diamine of general formula H2N-R1-NH2(II),

[0115] Sub-step 1 b: reacting the product obtained in sub-step 1 with an aromatic diamine H2N-R2-NH2to obtain the amine-terminated extended imide (V).

[0116] Preferably, the process for preparing the bismaleimide compound of general formula (I) is carried out in one pot, without isolation of the intermediate compounds, such as the amine-terminated extended imide (V).

[0117] The reaction mixture comprises a mixture of compounds of general formula (I) in which R1, R2, Y, n, m can vary according to the parameters chosen for carrying out the reaction. The person skilled in the art is familiar with the preparation of bismaleimide compounds and understands that, in addition to the compounds of general formula (I) and the intermediate compounds according to the application, other products can be present in the reaction mixture. For example, the mixture can comprise some compounds of general formula (I) with n = 0 and some compounds of general formula (I) with m = 0.

[0118] Curable resin composition

[0119] The bismaleimide compound of formula (I) and / or the bismaleimide compound obtained from the above disclosed method is advantageously comprised in the resin composition in an amount of about 20 to 99 wt%, more preferably about 30 to 98 wt%, based on the total weight of the resin composition.

[0120] In addition to the bismaleimide compound of formula (I) and / or the bismaleimide compound obtained from the above disclosed method, the resin composition advantageously comprises a co-curing agent or a thermally curable resin.

[0121] The application of a co-curing agent in the resin composition can lower the curing temperature or promote the curing reaction. According to one preferred embodiment, the composition of the present application comprises at least a co-curing agent and a thermally curable resin, which can be selected from, for example, polyphenylene ether derivatives, maleimides, styrene, divinylbenzene, trivinylcyclohexane, trienyl isocyanurate compounds and mixtures thereof.

[0122] The co-curing agent is advantageously selected from trienyl isocyanurate compounds, such as triallyl isocyanurate (TAIC).

[0123] The amount of the co-curing agent applied is adjusted according to the amount of the unsaturated group contained in the curable resin composition, the selection of the specific co-curing agent, its half-life temperature and the required stability. In one embodiment, the curable resin composition of the present application can include co-curing agents and mixtures thereof in an amount of about 1 to 50 wt% or about 2 to 20 wt%, based on the total weight of the composition with additives.

[0124] Additional components

[0125] Before curing, the curable resin composition can be mixed with various additives selected according to the intended use and the intended performance. These additives are described in detail below in a non-limiting manner. In this chapter, the percentages are weight percentages of the additional compounds expressed with respect to the total weight of the resin composition with additives.

[0126] While the resin composition of the present application can be cured by heating alone, a curing catalyst that generates a radical species can be added to improve the curing efficiency. Examples of such a curing catalyst include, but are not limited to, benzoin compounds such as benzoin and benzoin-methyl; acetophenone compounds such as acetophenone and 2,2-dimethoxy-2-phenylacetophenone and the like; thioxanthone compounds such as thioxanthone and 2,4-diethylthioxanthone; bisazido compounds such as 4,4'-bisazidochalcone, 2,6-bis(4-azidobenzylidene)cyclohexanone and 4,4'-bisazidobenzophenone; azo compounds such as azobisisobutyronitrile, 2,2-azobispropane, m.m'-oxyazobenzyI-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.

[0127] The resin composition can include about 0.1 to 10 wt% or about 0.3 to 7 wt% or about 0.5 to 5 wt% or about 1 to 3 wt% of the curing catalyst, where wt% is based on the total weight of the resin composition.

[0128] In another embodiment, to improve storage stability, a polymerization inhibitor can optionally be added to the resin composition. Examples include quinones and aromatic diols such as hydroquinone, p-benzoquinone, tetrachloro-p-benzoquinone, trimethylquinone and 4-tert-butylcatechol. When present, the resin composition can include about 0.0005 to 5 wt% of the polymerization inhibitor, where wt% is based on the total weight of the resin composition.

[0129] In another embodiment, the resin composition can optionally include an inorganic filler, an organic filler, or a mixture thereof. It is contemplated that the fillers used in the practice of the present application can be in any of a variety of morphologies, such as angular, flaky, spherical, amorphous, sintered, fired, powders, flakes, crystalline, ground, crushed, milled, and the like, or mixtures of any two or more thereof. At present, the preferred particulate fillers contemplated for use herein are substantially spherical.

[0130] Such fillers can optionally be thermally conductive. Both powders and flakes of the fillers can be used in the resin composition of the present application. Fillers having a wide range of particle sizes can also be employed in the practice of the present application. Particle sizes of about 500 nm to about 300 microns can be employed, preferably less than about 100 microns, and particularly preferred are particle sizes of about 5 to about 75 microns.

[0131] A wide variety of fillers can be used in practicing the present application, such as soft fillers (e.g., uncalcined talc), natural minerals (e.g., aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesium oxide, silicon dioxide, aluminum oxide, aluminum silicate, etc.), calcined natural 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, etc.

[0132] Exemplary fillers include talc, mica, calcium carbonate, calcium sulfate, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesium oxide, silicon dioxide, aluminum oxide, TiO2, aluminum silicate, zirconium silicate, cordierite, silane-treated minerals, polytetrafluoroethylene, polyphenylene sulfide, etc.

[0133] Thermally conductive fillers that can optionally be used in practicing the present application include, for example, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, beryllium oxide, magnesium oxide, silicon dioxide, aluminum oxide, zirconium silicate, etc. Preferably, these fillers have a particle size of about 20 microns. If aluminum nitride is used as a filler, it is preferably passivated by an adherent conformal coating (e.g., silicon dioxide, etc.).

[0134] When present, the resin composition can include up to about 75 wt%, or up to about 50 wt%, or up to about 25 wt%, or even up to about 10 wt% of the filler, where wt% is based on the total weight of the resin composition.

[0135] In another embodiment, the resin composition can be dissolved or dispersed in an organic solvent to form a resin composition varnish. The amount of solvent is not limited, but is typically a sufficient amount to provide a solid concentration of at least about 30 wt% to no more than about 90 wt% solids, or about 50-85 wt% solids, or about 55-75 wt% solids in the solvent.

[0136] The organic solvent is not particularly limited, and can be a ketone, an aromatic hydrocarbon, an ester, an amide, or an alcohol. More specifically, examples of organic solvents that can be used include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, methoxyethyl acetate, ethoxyethyl acetate, butoxyethyl acetate, ethyl acetate, N-methylpyrrolidone carboxamide, 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 monoethyl ether, triethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, and mixtures thereof.

[0137] The resin composition of the present application can optionally include one or more additives such as softening agents, antioxidants, dyes, pigments, surfactants, antifoams, silane coupling agents, dispersants, thixotropic agents, processing aids, flow modifiers, cure accelerators, strength enhancers, toughening agents, UV protectants (particularly UV blocking dyes suitable for use in enabling automated optical inspection (AOI) of electrical circuits), flame retardants, and the like, as well as mixtures of any two or more thereof.

[0138] Softening agents (also known as plasticizers) contemplated for use in certain embodiments of the present application include compounds that lower the brittleness of the formulation, such as branched polyalkanes or polysiloxanes that lower the glass transition temperature of the composition. Such plasticizers include, for example, polyethers, polyesters, polythiols, polythioethers, polybutadienes, such as those sold under the trade name Poly and When used, the plasticizer is typically present in an amount of about 0.5 to 30 wt% of the weight of the resin composition.

[0139] Antioxidants contemplated for use in practicing the present application include hindered phenols (such as BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole), TBHQ (tert-butylhydroquinone), 2,2'-methylenebis(6-tert-butyl-p-cresol), and the like), hindered amines (such as diphenylamine, N,N'-bis(l,4-dimethylpentyl-p-phenylenediamine, N-(4-anilinophenyl)methacrylamide, 4,4'-bis(alpha,alpha-dimethylbenzyl) diphenylamine, and the like), phosphites, and the like. When used, the amount of antioxidant is typically about 100 to 2000 ppm relative to the weight of the resin composition.

[0140] Dyes contemplated for use in certain embodiments of the present application include aniline black, Orasol Blue GN, phthalocyanines, fluorescent dyes (such as fluorescent green gold dye and the like), and the like. When used, relatively low amounts of organic dyes (i.e., in amounts less than about 0.2 wt%) provide contrast.

[0141] Pigments contemplated for use in certain embodiments of the present application include any particulate material added solely to impart color to the formulation, such as carbon black, metal oxides (such as Fe2O3, titanium oxide), and the like. When present, the pigments are typically present in an amount of about 0.5 to 5 wt% relative to the weight of the resin composition.

[0142] Toughening agents contemplated for use in practicing the present application are materials that impart enhanced impact resistance to various articles. Exemplary toughening agents include synthetic rubber-containing compounds such as Hypro, Hypoxy, and the like.

[0143] UV protectants contemplated for use in certain embodiments of the present application include compounds that absorb incident ultraviolet (UV) radiation, thereby reducing the negative effects of such exposure on the resin or polymer system to which the protectant is added. Exemplary UV protectants include bis(l,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, silicon, powdered metal compounds, hindered amines (referred to in the art as "HALS"), and the like.

[0144] Defoamers contemplated for use in certain embodiments of the present application include materials that inhibit the formation of foam or bubbles when a liquid solution is agitated or sheared during processing. Exemplary defoamers contemplated for use herein include n-butanol, silicon-containing defoamers, and the like.

[0145] Exemplary silane coupling agents contemplated for use in practicing the present application include materials that form bridges between inorganic surfaces and reactive polymeric components, including epoxy silanes, amino silanes, and the like.

[0146] Exemplary thixotropic agents contemplated for use in practicing the present application include materials that impart enhanced fluidity to a liquid when shear is applied, including high surface area fillers having a particle size in the range of about 2-3 microns or even sub-micron size (e.g., fumed silica), and the like.

[0147] The resin composition of the present application can be prepared by mixing the above components appropriately, and kneading or mixing by a kneading device such as a 3-roll mill, a ball mill, a bead mill, or a sand mill, or a stirring device such as a high-speed rotary mixer, a super mixer, or a planetary mixer, as necessary. In addition, the resin composition varnish can also be prepared as described above by adding one of the above organic solvents or a mixture thereof. The amount of the solvent is not limited, but is generally applied in a sufficient amount to provide a solid concentration of at least 30 wt% to not more than 90 wt% solids, or about 50%-85 wt% solids, or about 55-75 wt% solids, in the solvent.

[0148] Curing

[0149] According to another embodiment of the present application, there is provided an article comprising a partially or fully cured layer of the above-described resin composition. According to a preferred embodiment, the article provided comprises a partially or fully cured layer of the above-described resin composition on a substrate.

[0150] When the resin is cured by heating, the curing temperature varies depending on the type and amount of the resin composition and the curing agent used. The curing temperature is generally about 20-250°C, preferably about 50-250°C.

[0151] Applications

[0152] According to another embodiment of the application, there is provided an article comprising a partially or fully cured layer of the above composition, preferably in combination with a substrate.

[0153] The cured article can suitably be used as an organic insulating material or the like for applications in electronic devices such as communication devices, in particular for the preparation of high frequency laminates.

[0154] The choice of diamines (II) and (III), dianhydrides (IV), their ratio and the choice of parameters for the formation of the bismaleimide compound of general formula (I) provide a resin composition having improved properties in terms of processing, dielectric properties, thermodynamic properties and reduced water sensitivity.

[0155] The present application relates to a process for the preparation of an article, said process comprising at least the steps of preparing the above-described curable resin composition, shaping said composition and curing said composition.

[0156] Shaping comprises structuring the composition by giving it the desired shape and / or combining the composition with other materials, such as a carrier material, also referred to as a substrate or support article. Shaping can comprise the step of dissolving the resin composition in a solvent. Several variants of the process for the preparation of an article according to the present application are described in detail below:

[0157] The present application also relates to a process for the preparation of an article, such as a high frequency laminate, said process comprising at least the steps of:

[0158] - Step 1 : preparing a curable resin composition as disclosed above,

[0159] - Step 2: dissolving the curable resin composition of Step 1 in a solvent to form a varnish and applying the varnish to a support article,

[0160] - Step 3: curing said composition.

[0161] Applying the varnish to a support article can be achieved by any method known to the person skilled in the art, for example, brushing the curable resin composition on the support article, spraying the curable resin composition on the support article, or spin-coating the curable resin composition on the support article.

[0162] The present application also relates to a process for the preparation of an article, in particular a high frequency laminate, said process comprising at least the steps of:

[0163] - Step 1 : preparing a curable resin composition as disclosed above,

[0164] - Step 2: impregnating a carrier material, in particular a fibrous material, with the composition of Step 1,

[0165] - Step 3: curing said composition.

[0166] Impregnation of the fibrous material with the curable resin composition can be achieved by any method known to those skilled in the art, for example, by immersing the fibrous material in a solution of the curable resin mixture, or by spraying the curable resin composition on the fibrous material, or by spin-coating the curable resin composition on the fibrous material. This method can require the curable resin composition to be dissolved in a solvent to form a varnish.

[0167] The present application also relates to a process for the preparation of an article, said process comprising at least the following steps:

[0168] - Step 1 : preparation of the curable resin composition as disclosed hereinabove,

[0169] - Step 2: introduction of the composition of Step 1 into a mold,

[0170] - Step 3: partial or complete curing of said composition.

[0171] The present application also relates to an article obtained by a process comprising at least the step of curing the composition of the present application.

[0172] The composition of the present application enables to provide articles useful for various applications, such as prepregs, metal clad laminates (such as copper clad laminates), printed circuit boards, light emitting diodes and electronic coatings.

[0173] In particular, the present application relates to a prepreg obtained by impregnating a fibrous material with the curable resin composition of the present application and curing said resin.

[0174] The present application also provides a laminate useful as a high frequency laminate, wherein said laminate comprises a prepreg as defined above and a layer of electrically conductive material located on at least one surface of the prepreg.

[0175] The present application also relates to a printed circuit board produced by forming an electrically conductive pattern on the surface of a laminate as defined above.

[0176] As will be readily appreciated by those skilled in the art, a variety of substrates are suitable for use in practicing the present application, such as polyesters, liquid crystal polymers, polyamides (such as aromatic polyamides), polyimides, polyamide-imides, polyolefins, polyphenylene ethers, polyphenylene sulfides, polybenzoxazines, electrically conductive materials (such as electrically conductive metals), and the like, as well as combinations of any two or more thereof. When an electrically conductive metal substrate is employed, it is contemplated herein that silver, nickel, gold, cobalt, copper, aluminum, alloys of these metals, and the like, are materials of use.

[0177] According to another embodiment of the present application, there is provided a method of making the aforementioned article (i.e., an article comprising the inventive composition on a substrate / supporting article), which method comprises applying the resin composition to the substrate, and if an organic solvent is optionally used to facilitate such application, removing substantially all of the organic solvent therefrom. The resin composition can be applied to the substrate by dipping, immersion, spraying, etc.

[0178] According to another embodiment of the present application, there is provided a prepreg prepared by impregnating a porous substrate with the resin composition of the present application, and if an organic solvent is optionally used to facilitate such impregnation, subjecting the resulting impregnated substrate to conditions suitable for removing substantially all of the organic solvent therefrom.

[0179] As will be readily appreciated by those skilled in the art, a variety of porous substrates can be used to prepare the prepreg of the present application. The porous substrate can be woven or non-woven. The thickness of such substrate is not particularly limited and can be, for example, from about 0.01 mm to 0.3 mm.

[0180] Examples of porous substrates can include, but are not limited to, woven glass, non-woven glass, woven aramid fibers, non-woven aramid fibers, woven liquid crystal polymer fibers, non-woven liquid crystal polymer fibers, woven synthetic polymer fibers, non-woven synthetic polymer fibers, randomly dispersed fiber reinforcements, expanded polytetrafluoroethylene (PTFE) structures, and combinations of any two or more thereof. In particular, it is contemplated that the materials useful as the porous substrate can include, but are not limited to, glass fibers, quartz, polyester fibers, polyamide fibers, polyphenylene sulfide fibers, polyetherimide fibers, cyclic olefin copolymer fibers, polyalkylene fibers, liquid crystal polymers, poly(p-phenylene-2,6-benzobisoxazole), a copolymer of polytetrafluoroethylene and perfluoromethylvinylether (MFA), and combinations of any two or more thereof.

[0181] According to another embodiment of the present application, there is provided a laminate produced by layering and molding a prescribed number of sheets of the aforementioned prepreg.

[0182] The laminate of the present application has a number of particularly beneficial properties, such as low dielectric constant, low dissipation factor, high thermal decomposition temperature, etc. In a preferred embodiment, the laminate of the present application has a nominal dielectric constant of < 4.0 at 10 GHz, a dissipation factor of < 0.004, and a glass transition temperature of at least 100°C, or better, at least 150°C, and even better, at least 200°C.

[0183] In one aspect of the present application, the laminate as described herein can optionally further comprise one or more electrically conductive layers. Such optional electrically conductive layers are selected from metal foils, metal plates, electrically conductive polymer layers, etc. In one embodiment, the metal can be copper, silver, nickel, gold, cobalt, aluminum, and alloys of these metals.

[0184] In another embodiment, a method for forming a laminate is provided. The method comprises contacting a porous substrate with a varnish bath comprising a resin composition of the present invention dissolved and thoroughly mixed in a solvent or solvent mixture. The contacting occurs while the porous substrate is coated with the resin composition. The coated porous substrate is then passed through a heating zone having a temperature sufficient to evaporate the solvent but below a temperature at which the resin composition will substantially solidify during its residence time in the heating zone to form a prepreg.

[0185] The residence time of the porous substrate in the bath is preferably 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 a bath is preferably from about 0° C. to 100° C., more preferably from about 10° C. to 40° C., and most preferably from about 15° C. to 30° C. The residence time of the coated porous substrate in the heated zone is from about 0.1 to 15 minutes, more preferably from about 0.5 to 10 minutes, and most preferably from about 1 to 5 minutes.

[0186] The temperature in this zone is sufficient to volatilize any residual solvent, but not so high as to cause complete curing of the components during the residence time. The preferred temperature in this zone is about 80-250°C, more preferably about 100-225°C, and most preferably about 150-210°C. Preferably, there is a method to remove the solvent in the heating zone by passing an inert gas through the oven or pulling a slight vacuum on the oven. In many embodiments, the coated substrate is exposed to the zone with elevated temperature. The first zone is designed to volatilize the solvent so that it can be removed. The subsequent zone is designed to partially cure the resin composition (B stage).

[0187] Preferably, one or more prepregs are processed into a laminate, optionally together with one or more conductive materials (such as copper). In this further processing, one or more fragments or parts of the coated porous substrate are contacted with each other and / or with the conductive material. Subsequently, the contact portion is exposed to an elevated pressure and temperature sufficient to cure the component, wherein the resin on the adjacent parts reacts to form a continuous resin matrix between the porous substrates. Before curing, the components can be cut and stacked or folded and stacked into components of the desired shape and thickness. The pressure used can be about 1-1000psi, preferably about 10-800psi. The temperature of the resin composition used in the cured component or laminate depends on the specific residence time, the pressure used and the components used. The preferred temperature that can be applied is about 100-250°C, more preferably about 120-220°C, and most preferably about 170-200°C. The residence time is preferably about 10-120 minutes, and more preferably about 20-90 minutes.

[0188] In one embodiment, the process is a continuous process in which the porous substrate is removed from the oven, properly arranged into the desired shape and thickness, and pressed at a very high temperature for a short period of time. Specifically, the high temperature is about 180-250°C, more preferably about 190-210°C, for a period of about 1-10 minutes and about 2-5 minutes. This high-speed pressing allows for more efficient use of processing equipment. In this embodiment, the preferred reinforcement material is glass mesh or woven cloth.

[0189] In some embodiments, it is desirable to post-cure the laminate or final product outside of the press. This step is intended to complete the curing reaction. Post-curing is typically performed at about 130-220°C for a time interval of about 20-200 minutes. This post-curing step can be performed in a vacuum to remove any volatile components.

[0190] Therefore, according to another embodiment of the present invention, there are provided several methods for preparing laminates, said methods comprising laminating and molding a specified number of prepreg sheets of the present invention.

[0191] According to another embodiment of the present invention, a printed wiring board is provided, which is produced by forming a conductive pattern on the surface of the above-mentioned laminate. The conductive pattern can be formed by, for example, forming a resist pattern on the surface of the laminate, removing unnecessary portions of the board by etching, removing the resist pattern, forming desired through-holes by drilling, forming the resist pattern again, plating to connect the through-holes, and finally removing the resist pattern.

[0192] According to another embodiment of the present invention, there is provided a multilayer printed wiring board produced by stacking and molding a prescribed number of sheets of the above-mentioned patterned laminate layer and bonding them together with one or more layers of prepreg for producing a printed wiring board layer.

[0193] According to another embodiment of the present invention, there is provided a method for producing a printed wiring board, the method comprising forming a conductive pattern on a surface of the laminate of the present invention.

[0194] According to another embodiment of the present invention, there is provided a multilayer printed wiring board, which is manufactured by stacking and molding a prescribed number of the above-mentioned prepreg sheets to obtain a printed wiring board for an inner layer, and laminating the prepreg onto an inner layer printed circuit board having a conductive pattern formed on the surface.

[0195] Therefore, the prepreg and printed wiring board of the present invention can be usefully used as components of network printed circuit boards for various electrical and electronic devices, such as mobile communication devices or base station devices thereof that process GHz or higher frequency signals, as well as network-related electronic devices such as servers and routers and mainframe computers.

[0196] In some embodiments, the resin composition of the present application can have a flat dielectric loss factor (D f ) over a wide frequency range, such that the components made therefrom can be effectively operated at several different processing speeds. This is important because many prior art electronic devices can be operated over a certain frequency range, and it is desirable that the electronic components maintain proper function over the entire frequency range.

[0197] It has been found that the application of the composition of the present application enables to reach ultra-low loss factor D f (e.g. 1-10 GHz, below 0.005 at 10 GHz), which is unexpected in the prior art.

[0198] In particular, the curable resin composition of the present application, when cured, yields a product having a dielectric loss factor (D f ) measured on a split post dielectric resonator (SPDR) at a frequency of 10 GHz of less than 0.005, preferably less than 0.004, more preferably less than 0.0035.

[0199] According to the most preferred embodiment, the product obtained from curing the composition of the present application has a dielectric constant (D k ) at 10 GHz of less than about 4 or less than about 3.5.

[0200] In particular, the curable resin composition of the present application, when cured, yields a product having a Tg higher than or equal to about 100°C, preferably higher than or equal to about 150°C, more preferably higher than about 200°C.

[0201] The present application will be further described below with reference to the following non-limiting examples.

[0202] Examples

[0203] Materials:

[0204] Priamine Aliphatic C36 dimer diamine commercially available from CRODA

[0205] DAPI: aromatic amine (diamino-1,3,3-trimethyl-1 -phenylindan) commercially available from HUNTSMAN

[0206] Pyromellitic dianhydride commercially available from CABB Group (formerly JAYHAWK).

[0207] Example 1 - Preparation of bismaleimide compounds

[0208] Example 1a - Preparation of a bismaleimide compound of the present application: A 2L reaction flask equipped with a stirrer and a Dean-Stark trap was charged with 0.2734 moles of pyromellitic dianhydride in 550 ml of toluene and 220 ml of N-methyl pyrrolidone and the mixture was heated to 90-95°C. 0.082 moles of Priamine was introduced in 120 ml of toluene. The temperature was raised to 125°C and the reaction was continued under reflux conditions for 20 minutes. 0.328 moles of 4',5-6-diamino-1,3,3-trimethyl-1 -phenylindane (DAPI) in 110 ml of toluene and 130 ml of N-methyl pyrrolidone was introduced. The temperature was raised to 125°C and the reaction was continued under reflux conditions for 2 hours. The reaction mixture was cooled to 100°C and 0.3034 moles of maleic anhydride and 0.0802 moles of p-toluenesulfonic acid monohydrate were introduced. The temperature was raised to 125°C and the reaction was continued under reflux conditions for 5 hours. The solution was washed with brine and the toluene was removed under vacuum. The solid was then purified by dissolution in N-methyl pyrrolidone followed by precipitation in methanol and vacuum drying. The mass yield was 70%. Analysis1H,1C NMR, HPLC, GC and GPC were performed and the structure of the expected product was confirmed in the reaction mixture.

[0209] Example 1 b - Preparation of a comparative bismaleimide compound: Following the protocol of Example 1 a, DAPI was used instead of Priamine

[0210] Example 1 c - Preparation of a comparative bismaleimide compound: Following the protocol of Example 1 a, Priamine was used instead of DAPI.

[0211] Example 2 - Preparation of inventive and comparative resin compositions

[0212] The components identified in Table 1 were dissolved in toluene at room temperature to produce homogeneous resinous composition varnishes (compositions C1 a, C1 b and C1 c) at a concentration of 50-60 wt% solids.

[0213] Table 1

[0214]

[0215] Example 3 - Application - Preparation of prepregs and laminates

[0216] A glass fiber fabric (E2116NE glass) was immersed in the varnish and then placed vertically in an oven at 140°C for 2 minutes to dry to produce a prepreg sheet.

[0217] The above prepreg sheet was pressed and cured at 220°C for 2 hours to produce a final laminate with a resin content of about 45-50 wt%.

[0218] The dielectric constant (D) of the obtained laminated material with a thickness of about 0.5 mm was measured on a separated pillar dielectric resonator (SPDR) at a frequency of 10 GHz. k ) and dissipation factor (D f ) were evaluated and the glass transition temperature was measured at 2° C. / min from 23° C. to 300° C. at 1 Hz in oscillation mode. The glass transition was determined by G′ onset and tan δ as a maximum value.

[0219] Table 2

[0220]

[0221] The results clearly demonstrate the effect of using aromatic and aliphatic amines and mixtures. Compared to Example 1a, the dielectric loss of the fully aromatic bismaleimide (Example 1b) is significantly increased, while the glass transition temperature of the bismaleimide based on aliphatic amines (Example 1c) is significantly lower than that of Example 1a.

[0222] Although the preparation and application of various embodiments of the present invention have been described in detail above, it should be understood that the present invention provides many applicable inventive concepts that can be implemented in a variety of specific contexts. The specific embodiments discussed herein only describe specific ways to prepare and apply the present invention and do not limit the scope of the invention.

Claims

1. Bismaleimide compounds of general formula (I): in n is an integer, ranging from 1 to 10. m is an integer, ranging from 1 to 10. Each Q is independently a tetravalent group selected from C6-C50 hydrocarbons, which contains at least one aromatic group and optionally one or more heteroatoms selected from O, N, S, F, Cl, Br, Each R1 is independently a divalent radical selected from aliphatic and aromatic linear or branched C1-C60 hydrocarbons, optionally containing one or more NH2 groups, one or more NH bridges, Each R2 is independently a divalent group selected from C6-C54 aromatic hydrocarbons, which optionally contain one or more halogen atoms, R is a divalent group R1 or R2, Y represents H or CH3.

2. The bismaleimide compound of claim 1, wherein Q is selected from the following structures: wherein Q′ is a divalent group selected from C1-C38 hydrocarbons, which optionally contain one or more heteroatoms selected from O, N, S, F, Cl and Br.

3. The bismaleimide compound of claim 1 or 2, wherein each R1 is independently selected from a C12-C60 alkyl, alkenyl or aralkyl group, which optionally contains one or more NH2 groups, one or more NH bridges.

4. The bismaleimide compound according to any one of claims 1 to 3, wherein each R2 is independently selected from a divalent group of the general formula (IIIA): in Y1 and Y2 independently represent H, C1-C5 alkyl, Each of Y3 and Y4 independently represents H, halogen, or C1-C4 alkyl.

5. A method for preparing the bismaleimide compound according to any one of claims 1 to 4, comprising the steps of: Step 1: reacting dianhydride (IV) with diamine of formula (II) and diamine of formula (III) to obtain amine-terminated extended imide (V), Step 2: reacting the amine-terminated extended imide (V) obtained in step 1 with a maleic anhydride compound (VI), in n, m, Q, R1, R2, R and Y are the same as those defined in the general formula (I), An and Am represent the relative molar amounts of diamine H2N-R1-NH2 and diamine H2N-R2-NH2, respectively, introduced into the reaction medium relative to the amount of dianhydride (IV).

6. The method of claim 5, wherein the ratio of the total amount of amine (Am+An) to the dianhydride compound is from about 5:1 to about 1.05:

1.

7. The process of claim 5 or 6, wherein the molar ratio Am / An of aromatic amine (III) to aliphatic amine (II) is 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 according to any one of claims 5 to 7, wherein the first step of the method is carried out in two sub-steps: Sub-step 1a: reacting dianhydride (IV) with an aliphatic diamine of the general formula H2N-R1-NH2(II), Sub-step 1b: reacting the product obtained in sub-step 1 with an aromatic diamine H2N-R2-NH2 to obtain an amine-terminated extended imide (V).

9. The process of any one of claims 5 to 8, wherein the process is carried out in one kettle.

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

11. A curable resin composition comprising at least the bismaleimide compound of general formula (I) according to any one of claims 1 to 4 or 10 and at least one co-curing agent.

12. The curable resin composition of claim 11, wherein the co-curing agent is selected from the group consisting of polyphenylene ether derivatives, maleimide, styrene, divinylbenzene, trivinylcyclohexane, trialenyl isocyanurate compounds and mixtures thereof, preferably trialenyl isocyanurate compounds, such as triallyl isocyanurate.

13. The curable resin composition of claim 11 or 12, wherein the bismaleimide compound accounts for about 20-99 wt %, more preferably about 30-98 wt %, based on the total weight of the composition, and the co-curing agent accounts for about 1-50 wt %, preferably about 2-20 wt %, based on the total weight of the composition.

14. A method for producing a product, comprising at least the following steps: -Step 1: preparing the curable resin composition according to any one of claims 11 to 13, -Step 2: shaping the composition, -Step 3: The composition is partially or fully cured.

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

16. The article of claim 15, having a dielectric loss factor (D ) measured on a split-pin dielectric resonator (SPDR) at a frequency of 10 GHz. f ) is less than 0.005, preferably less than 0.004, more preferably less than 0.0035, and its dielectric constant (D k ) is less than about 4 or less than about 3.5, and its Tg is higher than or equal to 100°C, preferably higher than or equal to 150°C, more preferably higher than or equal to 200°C.

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

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

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

20. Use of the resin composition of any one of claims 1 to 4 and 10 in prepregs, metal clad laminates, printed circuit boards, light emitting diodes, electronic coatings, textiles, polymer molding compounds, medical molding compounds and adhesives.

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