Curable and cured thermosetting compositions

Abstract

A curable thermoset composition and a cured thermoset composition are provided. The thermoset composition may be prepared to have a low coefficient of thermal expansion (CTE) in the range of 0 to 100 degrees Celsius, a low dielectric constant (e.g., less than 2.5), a low dielectric loss tangent (e.g., less than 0.004 at 10 GHz), or a combination thereof. The curable thermoset composition contains an addition polymerized polynorbornene copolymer, a bismaleimide resin having a high level of hydrocarbon content, and a thermal radical initiator.

Description

BACKGROUND OF THE INVENTION

[0001] Some components of integrated circuit packages require curable films that can be thermally laminated to a substrate and then cured in place at elevated temperatures (e.g., 180 degrees Celsius to 200 degrees Celsius) to form a thermosetting composition having a high glass transition temperature (e.g., greater than 110 degrees Celsius). Although epoxy resins can be used to provide the desired thermosetting material, they typically have unacceptably high dielectric constants and dielectric loss tangent (i.e., dissipation factor (Df)). Alternative thermosetting compositions are desired, particularly in the integrated circuit (IC) package space. SUMMARY OF THE INVENTION

[0002] Curable thermosetting compositions and cured thermosetting compositions are provided. These thermosetting compositions can be prepared to have a low coefficient of thermal expansion (CTE) in the range of 0 degrees Celsius to 100 degrees Celsius, a low dielectric constant (e.g., less than 2.5), a low dielectric loss tangent (e.g., less than 0.004), or a combination thereof. The curable thermosetting composition contains an addition-polymerized norbornene copolymer, a bismaleimide resin having a high level of hydrocarbon content, and a thermal free radical initiator.

[0003] In a first aspect, a curable composition is provided. The curable composition comprises curable components that comprise (a) an addition-polymerized norbornene copolymer having norbornene monomer units containing crosslinkable pendant groups; (b) a bismaleimide compound; and (c) a thermal free radical initiator. The bismaleimide compound present in an amount equal to at least 5 wt% (e.g., in the range of 5 wt% to less than 80 wt%) based on the total weight of the curable components contains (1) two bismaleimide groups and (2) at least one C36 hydrocarbon group having 0 to 3 carbon-carbon double bonds.

[0004] In a second aspect, a cured composition is provided. The cured composition comprises the cured reaction product of the curable composition described in the first aspect after exposure to a temperature sufficient to activate the thermal initiator.

[0005] In a third aspect, a first article is provided. The first article includes a substrate and a layer of the curable composition adjacent to the substrate described in the first aspect.

[0006] In a fourth aspect, a second article is provided. The second article includes a layer of the cured composition and an optional substrate, wherein the cured composition is the same as that described in the second aspect.

[0007] The terms "a", "an", and "the" are used interchangeably, where "at least one" means one or more of the recited elements. The phrases "at least one of... " and "comprising at least one of... " followed by a list refer to any one of the items in the list and any combination of two or more items in the list.

[0008] The term "and / or" means either or both. For example, the expression X and / or Y means X, Y, or a combination thereof (both X and Y).

[0009] The term "alkyl" refers to a monovalent group that is an alkane group and includes straight-chain groups, branched-chain groups, cyclic groups, bicyclic groups, or combinations thereof. Unless otherwise specified, alkyl groups generally contain from 1 to 40 carbon atoms or from 1 to 20 carbon atoms. In some embodiments, the alkyl group contains from 1 to 10 carbon atoms, from 2 to 10 carbon atoms, from 1 to 6 carbon atoms, from 2 to 6 carbon atoms, from 1 to 4 carbon atoms, or from 2 to 4 carbon atoms. Cyclic alkyl groups and branched-chain alkyl groups have at least three carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, isobutyl, tert-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, and the like.

[0010] The term "alkylene" refers to a divalent group that is a group of an alkane and includes straight-chain groups, branched-chain groups, cyclic groups, bicyclic groups, or combinations thereof. Unless otherwise specified, alkylene groups generally contain from 2 to 40 carbon atoms. In some embodiments, the alkylene group contains from 2 to 36 carbon atoms, from 2 to 30 carbon atoms, from 2 to 20 carbon atoms, from 2 to 10 carbon atoms, from 2 to 8 carbon atoms, from 2 to 6 carbon atoms, from 2 to 4 carbon atoms, 3 carbon atoms, or 2 carbon atoms. Cyclic alkylene groups and branched-chain alkylene groups have at least three carbon atoms. Examples of alkylene groups include, but are not limited to, methylene, ethylene, n-propylene, n-butylene, n-pentylene, isobutylene, tert-butylene, isopropylene, n-octylene, n-heptylene, ethylhexylene, cyclopentylene, cyclohexylene, cycloheptylene, adamantylene, and norbornylene, and the like.

[0011] The term "alkene" refers to a hydrocarbon compound having a carbon-carbon double bond and includes straight-chain compounds, branched-chain compounds, cyclic compounds, bicyclic compounds, or combinations thereof. In some embodiments, the double bond is at the terminal position of a straight-chain or branched-chain compound, and the alkene can have the formula CH 2 =CH-R, where R is an alkyl group. In other embodiments, the alkene contains a cyclic group or a bicyclic group, and the carbon-carbon double bond is in the cyclic portion or bicyclic portion of the compound. Although an alkene can have multiple carbon-carbon double bonds, these compounds are not aromatic.

[0012] The term "alkenyl" refers to a monovalent group of an alkene.

[0013] The term "alkylidene" refers to a divalent group of a terminal alkene, where the group is attached to an adjacent atom through a carbon-carbon double bond.

[0014] The term "arylene" refers to a divalent group that is a group of an aromatic carbocyclic compound. The arylene group has at least one aromatic carbocyclic ring and may have 1 to 3 optional rings attached to or fused to the aromatic carbocyclic ring. The additional rings may be aromatic, aliphatic, or a combination thereof. The arylene group typically has 5 to 20 carbon atoms or 6 to 10 carbon atoms.

[0015] The term "curable" refers to a composition or component that can be cured. The terms "cured" and "curing" refer to joining polymer chains together through covalent chemical bonds to form a polymer network. The cured polymer network is typically characterized by insolubility, but it may be swellable in the presence of a suitable solvent. The curable composition typically comprises a polynorbornene copolymer, a bismaleimide compound, a thermal activator, and any other optional components.

[0016] The term "curable component" refers to those materials within the curable composition that participate in the curing reaction. Curable components are typically a polynorbornene copolymer, a bismaleimide compound, and a thermal activator. The term does not include any optional components.

[0017] The term "(hetero)hydrocarbon" refers to a hydrocarbon and / or a heterohydrocarbon. The term "hydrocarbon" refers to a compound or group that has only carbon and hydrogen atoms. The term "heterohydrocarbon" refers to a compound or group that has carbon, hydrogen, and heteroatoms. Heteroatoms typically include nitrogen, oxygen, and sulfur. The terms "(hetero)hydrocarbyl", "hydrocarbyl", and "hetero-carbyl" refer to a monovalent group. The terms "(hetero)carbylene", "carbylene", and "hetero-carbylene" refer to a divalent group.

[0018] As used herein, the term "norbornene-based monomer" refers to a compound of the formula

[0019]

[0020] where each X 1 and X 2 are independently hydrogen or a substituent, such as, for example, an alkyl group or a crosslinkable group containing a carbon-carbon double bond. The term "norbornene monomer" refers to a compound where X 1 and X 2are subsets of compounds of hydrogen having the above formula. The chemical structures of the substituted norbornene-based compounds are intended to cover all exo / endo isomers as well as all enantiomers / diastereomers consistent with the indicated atomic connectivity.

[0021] As used herein, the term "norbornene-based monomer unit" refers to a group of the following formula

[0022]

[0023] wherein each X 1 and X 2 is independently hydrogen or a substituent, such as, for example, an alkyl group or a crosslinkable group containing a carbon-carbon double bond. The term "norbornene monomer unit" refers to a subset of the groups of the above formula, wherein X 1 and X 2 are both hydrogen. The asterisk (*) indicates the attachment site to other monomer units (such as other norbornene monomer units) and / or end groups in the copolymer.

[0024] As used herein, the term "polymerizable composition" refers to a composition for forming a polynorbornene copolymer. It includes, for example, various types of norbornene-containing monomers and a catalyst or precatalyst / activator, an optional 1-olefin, an optional Lewis base, and any other optional materials such as solvents, etc.

[0025] The terms "polymer" and "polymer material" are used interchangeably and refer to a material formed by the reaction of one or more monomers. These terms include homopolymers, copolymers, terpolymers, etc. Similarly, the terms "polymerization" and "polymerize" refer to the process of preparing a polymer material, which can be a homopolymer, copolymer, terpolymer, etc. When the polymer material contains more than one type of monomer unit, the terms "polymer" and "copolymer" can be used interchangeably.

[0026] As used herein, any recitation of a range includes the end values of the range and all suitable values within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0027] As used herein, the term "room temperature" refers to a temperature of 20 degrees Celsius to 30 degrees Celsius, such as 20 degrees Celsius to 25 degrees Celsius, 22 degrees Celsius to 25 degrees Celsius, or 23 degrees Celsius.

[0028] The dashes on both sides of a group (such as -O-, -NH-, and -(C=O)-O-) indicate that these groups are divalent. The dash on one side of a group (such as -(C=O)-OH) indicates that the group is monovalent. Detailed Description

[0029] Provided are curable compositions and cured compositions comprising an addition-polymerized polynorbornene copolymer. Further provided are articles containing the curable composition or the cured composition. The cured composition is a thermosetting resin that can be used in various applications (such as for integrated circuit encapsulation). The cured composition is formed from a curable composition comprising curable components, the curable components comprising: (a) an addition-polymerized polynorbornene copolymer having norbornene-based monomer units containing crosslinkable pendant groups; (b) a bismaleimide compound in an amount equal to at least 5% by weight (e.g., in the range of 5% to less than 80% by weight) based on the total weight of the curable components; and (c) a thermal free radical initiator. The bismaleimide compound has (1) two bismaleimide groups and (2) at least one C36 hydrocarbon group having from 0 to 3 carbon-carbon double bonds. At least one C36 hydrocarbon group in the bismaleimide compound is generally aliphatic but may contain a single aromatic ring.

[0030] Curable composition

[0031] The curable composition comprises curable components, the curable components comprising an addition-polymerized polynorbornene copolymer, a bismaleimide compound that serves as a crosslinking agent for the addition-polymerized polynorbornene, and a thermal free radical initiator. Each curable component will be described below.

[0032] Addition-polymerized polynorbornene copolymer

[0033] The polynorbornene copolymer is the product of an addition polymerization reaction of a variety of different norbornene-based monomers. The polymerizable composition for forming the polynorbornene copolymer comprises at least one norbornene-based monomer having crosslinkable pendant groups. The polymerizable composition generally further comprises other norbornene-based monomers, such as those having pendant hydrocarbon groups (such as, for example, alkyl groups). Additionally, norbornene monomers (i.e., those having no pendant groups) may be included. The various monomers are polymerized in the presence of a catalyst, which generally comprises a Group 10 element of the periodic table.

[0034] Any suitable norbornene-based monomer having crosslinkable pendant groups can be used. As used herein, the term "crosslinkable group" refers to a group that is reactive when heated in the presence of a thermal free radical initiator. Crosslinkable groups generally contain reactive carbon-carbon double bonds.

[0035] In some embodiments, the norbornene-based monomer having crosslinkable pendant groups has the formula (I)

[0036]

[0037] wherein the side group R 1 is an alkenyl group or a sub-alkyl group. The alkenyl group or sub-alkyl group may have 2 or more carbon atoms, such as, for example, 2 to 10 carbon atoms. The number of carbon atoms may be at least 2 carbon atoms, at least 3 carbon atoms, or at least 4 and at most 10 carbon atoms, at most 8 carbon atoms, at most 6 carbon atoms, or at most 4 carbon atoms. Examples of the norbornene-based monomers of formula (I) have formula (I-A) or (I-B).

[0038]

[0039] These monomers can be commercially obtained, for example, from Millipore-Sigma and TCI America.

[0040] In other embodiments, the norbornene-based monomer having a crosslinkable side group has formula (II).

[0041]

[0042] In the monomer of formula (II), the crosslinkable group is the carbon-carbon double bond of a maleimide group. The group R 3 can be any suitable (hetero)hydrocarbon group. Each group R 4 is usually hydrogen or methyl. In many embodiments, both R 4 groups are hydrogen, or one R 4 group is methyl and the other is hydrogen.

[0043] In many embodiments, R 3 is an alkylene group, such as an alkylene group having 1 to 40 carbon atoms. The number of carbon atoms is at least 1 carbon atom, at least 2 carbon atoms, at least 3 carbon atoms, or at least 5 and at most 40 carbon atoms, at most 35 carbon atoms, at most 30 carbon atoms, at most 25 carbon atoms, at most 20 carbon atoms, at most 15 carbon atoms, at most 10 carbon atoms, at most 8 carbon atoms, at most 6 carbon atoms, or at most 4 carbon atoms. For example, R 3 can be an alkylene group having 1 or 2 carbon atoms. When R 3 is an alkylene group, the monomer of formula (II) can be prepared by reacting a norbornene-containing compound (1) having a side -R 3 -NH 2 group with maleic anhydride (2), as shown in the following reaction scheme A.

[0044] Reaction Scheme A

[0045]

[0046] Group R 3 and R 4 is the same as defined above. In some examples, R 3 is methylene or ethylene and each R 4 is independently hydrogen or methyl. Compounds (1) and (2) are commercially available, for example, from Millipore-Sigma.

[0047] In other embodiments, R in formula (II) 3 is a divalent group of the formula -R 5 -NH-(C=O)-R 6 -, where R 5 and R 6 are each an alkylene group, where R 5 is equal to -(CH 2 ) x - and R 6 is equal to -(CH 2 ) y -. The compound can be formed as shown in Reaction Scheme B.

[0048] Reaction Scheme B

[0049]

[0050] More specifically, compound (5) is the condensation reaction of compounds (3) and (4) in the presence of heat. Compound (3) contains group R 5 , which is an alkylene of the formula -(CH2) x}-, where the variable x is an integer in the range of 1 to 20. Compound (4) contains group R 6 , which is an alkylene of the formula -(CH 2 ) y}-, where y is an integer in the range of 1 to 20. The variables x and y can independently be at least 1, at least 2, at least 3, at least 4, at least 6 or at least 8 and at most 20, at most 18, at most 16, at most 12, at most 10, at most 8, at most 6, at most 5, at most 4 or at most 3.

[0051] In still other embodiments, the group R in formula (II) 3 is a divalent group of the formula

[0052]

[0053] where R 7 is an alkylene of the formula -(CH 2 ) q - and R 8is an alkylene group. The variable q is an integer in the range of 1 to 20, such as at least 1, at least 2, at least 3, at least 4, at least 6, or at least 8 and at most 20, at most 18, at most 16, at most 12, at most 10, at most 8, at most 6, at most 5, at most 4, or at most 3. The alkylene group R 8 can be saturated or unsaturated and can be linear, cyclic, or a combination thereof. The cyclic group can be saturated or unsaturated and can contain, for example, one or more alkylene groups. The group R 8 typically contains at least 6 carbon atoms, at least 8 carbon atoms, at least 10 carbon atoms, at least 12 carbon atoms, at least 16 carbon atoms, or at least 20 carbon atoms and at most 40 carbon atoms, at most 36 carbon atoms, at most 30 carbon atoms, at most 24 carbon atoms, at most 20 carbon atoms, at most 18 carbon atoms, at most 16 carbon atoms, or at most 10 carbon atoms. These groups can be formed, for example, by a condensation reaction such as that shown in Reaction Scheme C below, by reacting Compound (6) with Compound (7) to form Compound (8).

[0054] Reaction Scheme C

[0055]

[0056] Compound (7) can be formed, for example, by reacting a diamine of the following formula with maleic anhydride H 2 N-R 8 -NH 2 . In some embodiments, the compound H 2 N-R 8 -NH 2 is a dimeric diamine, where R 8 is an alkylene group having 36 carbon atoms. The alkylene contains 0 to 3 carbon-carbon double bonds. That is, R 8 is -C 36 -H 69 -, -C 36 H 70 -, -C 36 -H 71 -, or -C 36 H 72 -. In other embodiments, the diamine of the formula H 2 N-R 8 -NH 2 used to form Compound 7 contains R 8 having one or more aromatic groups. For example, R 8 can be a group of the following formula -Ar-R 2 -Ar-, where each Ar is an arylene such as phenylene, and R 2is an alkylene group having 1 to 6 carbon atoms. The alkylene group may have at least 1 carbon atom, at least 2 carbon atoms, at least 3 carbon atoms and at most 6 carbon atoms, at most 4 carbon atoms or at most 3 carbon atoms. In some examples, R 2 is methylene (-CH 2 -) or propylene (-C(CH 3 ) 2 -).

[0057] The polymerizable composition generally contains 2 mol% to 80 mol% of a crosslinking monomer (i.e., a monomer of formula (I-A), (I-B), (II) or a mixture thereof) based on the total number of moles of norbornene-based monomers. Within this range, higher amounts tend to produce a cured composition having a desired low coefficient of thermal expansion, but both the dielectric constant and the dielectric loss undesirably tend to increase. The amount of the crosslinking monomer is generally optimized based on the desired properties of the cured composition. The amount may be at least 2 wt%, at least 5 wt%, at least 10 wt%, at least 20 wt%, at least 30 mol%, at least 40 mol% or at least 50 mol% and at most 80 mol%, at most 75 mol%, at most 70 mol%, at most 65 mol%, at most 60 mol%, at most 65 mol%, at most 60 mol%, at most 50 mol%, at most 45 mol%, at most 40 mol%, at most 30 mol% or at most 35 mol% based on the total number of moles of norbornene-based monomers.

[0058] In addition to the crosslinking monomer, other norbornene-based monomers are generally also included in the polymerizable composition for forming the polynorbornene copolymer. For example, the polymerizable composition generally contains a norbornene-based monomer having a side-attached hydrocarbon group (such as, for example, an alkyl group). Such monomers may have the formula (III), wherein R 9 is an alkyl group.

[0059]

[0060] The alkyl group may have any suitable number of carbon atoms, but it generally contains 1 to 40 carbon atoms. The number of carbon atoms may be at least 1 carbon atom, at least 2 carbon atoms, at least 3 carbon atoms, at least 4 carbon atoms or at least 6 carbon atoms and at most 40 carbon atoms, at most 36 carbon atoms, at most 30 carbon atoms, at most 20 carbon atoms, at most 18 carbon atoms, at most 16 carbon atoms, at most 12 carbon atoms, at most 10 carbon atoms, at most 8 carbon atoms or at most 6 carbon atoms. In some embodiments, there are at least 4 or 6 carbon atoms and at most 10 carbon atoms.

[0061] The amount of the monomer of formula (III) can range from 0 mol% to 90 mol%, 10 mol% to 90 mol% or 20 mol% to 90 mol% based on the total molar amount of the norbornene-based monomers. The amount of this monomer is usually at least 20 mol%, at least 25 mol%, at least 30 mol%, at least 35 mol% or at least 40 mol% based on the total molar amount of the norbornene-based monomers, and can be up to 90 mol%, up to 84 mol%, up to 80 mol%, up to 75 mol%, up to 70 mol%, up to 65 mol%, up to 60 mol%, up to 55 mol%, up to 50 mol%, up to 45 mol% or up to 40 mol%.

[0062] In some embodiments, the polynorbornene copolymer is prepared from a polymerizable composition that further comprises a norbornene-based monomer having no substituent groups (i.e., norbornene). Norbornene is typically added to increase the glass transition temperature (Tg) of the polynorbornene copolymer. As a homopolymer, it has a Tg of nearly 300 degrees Celsius. However, the solubility of the homopolymer in many common solvents tends to be rather low, such that the norbornene-based monomer of formula (III) is usually added in an amount higher than norbornene. The amount of norbornene having no substituent groups can range from 0 mol% to 50 mol%. This amount is usually at least 1 mol%, at least 2 mol%, at least 3 mol%, at least 4 mol% or at least 5 mol% based on the total molar amount of the norbornene-based monomers, and up to 50 mol%, up to 40 mol%, up to 30 mol%, up to 25 mol%, up to 20 mol%, up to 15 mol%, up to 10 mol% or up to 5 mol%.

[0063] The polymerizable composition for forming the polynorbornene copolymer typically comprises 2 mol% to 80 mol% of a crosslinking monomer (such as those of formula (I), (IB) or (II)), 20 mol% to 90 mol% of a monomer having a pendant alkyl group (such as those of formula (III)) and 0 mol% to 50 mol% of norbornene. The amounts are based on the total molar amount of the norbornene-based monomers. In some embodiments, the polymerizable composition contains 5 mol% to 75 mol% of a crosslinking monomer, 25 mol% to 85 mol% of a monomer having a pendant alkyl group, and 1 mol% to 25 mol% of norbornene. In still other embodiments, the polymerizable composition contains 10 mol% to 60 mol% of a crosslinking monomer, 25 mol% to 80 mol% of a monomer having a pendant alkyl group, and 5 mol% to 20 mol% of norbornene. In yet other embodiments, the polymerizable composition contains 10 mol% to 50 mol% of a crosslinking monomer, 30 mol% to 80 mol% of a monomer having a pendant alkyl group, and 5 mol% to 10 mol% of norbornene.

[0064] The polymerizable composition for forming a polynorbornene copolymer may further comprise a compound having an ethylenically unsaturated group, such as a 1-olefin compound that is miscible with the norbornene-based monomer. The 1-olefin compound is typically added to control the molecular weight of the resulting polynorbornene copolymer, but is generally not incorporated or is only incorporated to a small extent into the polymer structure. For example, typically greater than 98 wt% of the 1-olefin monomer is not bound to the polynorbornene copolymer. That is, less than 2 wt%, less than 1 wt%, or less than 0.5 wt% of the 1-olefin is bound. Suitable 1-olefin monomers include, but are not limited to, those having 6 to 18 carbon atoms, such as 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, and the like. If a monomer having fewer than 6 carbon atoms is used, the monomer may be too volatile at the temperatures typically used for the polymerization reaction, such as near 70 degrees Celsius.

[0065] The polymerizable composition for forming a polynorbornene copolymer typically contains from 0 wt% to 60 wt% of a 1-olefin monomer, based on the total weight of the polymerizable composition. The amount of the 1-olefin can be 0 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, or at least 30 wt%, and up to 60 wt%, up to 55 wt%, up to 50 wt%, up to 45 wt%, up to 40 wt%.

[0066] The polynorbornene copolymer is polymerized using an addition polymerization method. As used herein, the term "addition polymerization" (which is sometimes also referred to in the art as vinyl addition polymerization) refers to a polymerization method involving an olefin coordination insertion pathway mediated by an organometallic catalyst. This method is distinct from a common alternative polymerization method, ring-opening metathesis polymerization (ROMP), both in terms of mechanism and reaction product. ROMP polymers contain double bonds in the polymer backbone, while the addition polymers according to the present disclosure do not contain double bonds. The addition polymerization reaction is typically carried out at room temperature or near room temperature for a period of several hours.

[0067] Many addition polymerization catalysts are known in the art and are generally based on organometallic catalysts containing Ti, Zr, Cr, Co, Fe, Cu, Ni, Pt, or Pd. Among these addition polymerization catalysts, addition polymerization catalysts containing Ni or Pd are commonly used. There is a large body of literature on organometallic addition polymerization catalysts, particularly for norbornene-type monomers. Generally, the active catalyst species is a cationic transition metal complex having alkyl or allyl ligands and weakly coordinating anions. The addition polymerization catalyst can comprise a single active species (or a combination thereof), or the addition polymerization catalyst can be provided as a combination of a precatalyst and an activator precursor. Generally, the precatalyst provides the active site for the olefin insertion mechanism to form the addition polymer. The combination with the activator converts the precatalyst into its active form.

[0068] In some embodiments, suitable catalysts or catalyst / pre-activator combinations for the addition polymerization of cycloolefins comprise Group 10 (i.e., in the Periodic Table of the Elements) catalysts or catalyst / pre-activator combinations. Group 10 catalysts (such as those based on Ni, Pd or Pt) may comprise a ring structure, such as a ring structure having a single carbon-carbon double bond. Alternatively, late metal (e.g., Ni- or Pd-based) pre-catalysts may have allyl / alkyl ligands as well as chloride ligands. These pre-catalysts are activated by addition of a monovalent metal (Li, Na, Ag) salt of a weakly coordinating anion (e.g., BF 4 4, tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (BARF) or perfluorotetraphenylborate). Typically, the molar ratio of activator to pre-catalyst is in the range of 10:1 to 1:10, such as in the range of 10:1 to 1:1, but other ratios may also be used.

[0069] Many useful addition polymerization catalysts and precatalyst / activator combinations are known and are disclosed in the following documents: for example, columns 8, line 28 to column 9, line 56 of U.S. Patent No. 3,330,815 (McKeon et al.); columns 3, line 9 to column 17, line 16 of U.S. Patent No. 6,455,650 B1 (Lipian et al.); columns 3, line 18 to column 31, line 53 of U.S. Patent No. 6,825,307 (Goodall); columns 3, line 31 to column 17, line 16 of U.S. Patent No. 6,903,171 B2 (Rhodes et al.); and columns 16, line 32 to column 28, line 31 of U.S. Patent No. 7,759,439 B2 (Rhodes et al.); columns 20, line 28 to column 21, line 30 of U.S. Patent No. 10,266,720 (Burgoon et al.); and paragraphs

[0015] to

[0075] of U.S. Patent Application Publication 2005 / 0187398 A1 (Bell et al.), the disclosures of which are incorporated herein by reference. Details regarding certain addition polymerization catalysts are also reported by M.V. Bermeshev and P.P. Chapala in “Addition polymerization of functionalized norbornenes as a powerful tool for assembling molecular moieties of new polymers with versatile properties”, Progress in Polymer Science (2018), 84, pages 1-46.

[0070] The addition of a Lewis base coordinated to a metal atom can improve the activity of an addition polymerization catalyst and / or a precatalyst. A Lewis base typically bonds to a metal atom by sharing two electrons from a lone pair of electrons of the metal atom. Any Lewis base known in the art can be used for this purpose. Preferably, the Lewis base can be easily dissociated under polymerization conditions. In some embodiments, the Lewis base is a phosphine-containing compound such as, for example, tricyclohexylphosphine.

[0071] In a catalyst solution for preparing an addition-polymerized polynorbornene copolymer, many different combinations of a precatalyst, an activator, and a Lewis base or a catalyst and a Lewis base can be used. In some embodiments, a precatalyst is used, and the precatalyst is a palladium-containing compound (e.g., Pd is a Group 10 element), the activator is a boron-containing salt, and the Lewis base is a phosphorus-containing compound. For example, a combination of allyl[1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]chloropalladium(II) as the precatalyst, sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the activator, and tricyclohexylphosphine as the Lewis base can be used for the addition polymerization of norbornene-based monomers.

[0072] Any suitable molar ratio of norbornene-based monomer to Group 10 element can be used. In some embodiments, the ratio can be at most 2000:1, at most 2500:1, at most 3000:1, at most 5000:1, at most 10,000:1, or even at most 20,000:1.

[0073] The weight-average molecular weight (Mw) of the polynorbornene copolymer is generally in the range of 10 kilodaltons (Da) to 1000 kilodaltons (Da). Mw is generally at least 10 kDa, at least 20 kDa, at least 25 kDa, at least 50 kDa, or at least 100 kDa and can be at most 1000 kDa, at most 500 kDa, at most 200 kDa, or at most 100 kDa. Mw can be measured by size exclusion chromatography (SEC).

[0074] The glass transition temperature (Tg) of the polynorbornene copolymer is generally in the range of 80 degrees Celsius to 280 degrees Celsius. Tg can be at least 80 degrees Celsius, at least 100 degrees Celsius, at least 120 degrees Celsius, or at least 150 degrees Celsius, and at most 280 degrees Celsius, at most 260 degrees Celsius, at most 250 degrees Celsius, at most 220 degrees Celsius, at most 200 degrees Celsius, at most 180 degrees Celsius, at most 160 degrees Celsius, or at most 150 degrees Celsius. Tg can be determined by the peak in the tan(δ) curve, which is obtained using dynamic mechanical analysis as described in the Examples section.

[0075] The curable component of the curable composition generally contains 20% to 95% by weight of a polynorbornene copolymer based on the total weight of the curable component. The curable component includes a polynorbornene copolymer, a bismaleimide compound, and a thermal free radical initiator. This amount can be at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight, at least 40% by weight, at least 45% by weight, at least 50% by weight, at least 55% by weight, or at least 60% by weight and at most 95% by weight, at most 90% by weight, at most 85% by weight, at most 80% by weight, at most 75% by weight, at most 70% by weight, at most 65% by weight, at most 60% by weight, at most 55% by weight, at most 50% by weight, at most 45% by weight, or at most 40% by weight of the polynorbornene copolymer.

[0076] Bismaleimide compound

[0077] The polynorbornene copolymer reacts with the bismaleimide compound to form a cured composition. The bismaleimide compound contains two maleimide groups and at least one C36 hydrocarbon group having 0 to 3 carbon-carbon double bonds. These C36 groups generally have 69, 70, 71, or 72 hydrogen atoms. Although these groups are generally mainly aliphatic, some C36 groups contain a single 6-membered aromatic ring. In some embodiments, there are at least two or more C36 groups.

[0078] Generally, crosslinking agents tend to reduce the coefficient of thermal expansion of the cured composition. While this is a desirable feature, many crosslinking agents tend to increase the dielectric constant (Dk) and the dielectric loss tangent (Df). For the use of this cured composition in the preparation of integrated circuit packaging systems, both a low dielectric constant and a low dielectric loss tangent are desirable. Surprisingly, relative to other common crosslinking agents, the bismaleimide crosslinking agent including at least one C36 group having 0 to 3 carbon-carbon double bonds tends to reduce both the dielectric constant and the dielectric loss tangent. Therefore, the use of these bismaleimide crosslinking agents can advantageously result in the formation of a cured composition having a low dielectric constant (e.g., Dk less than 2.5) and a low dielectric loss tangent (Df less than 0.004), while reducing the coefficient of thermal expansion in the temperature range from 0 °C to 100 °C. The frequency for measuring both the dielectric constant and the dielectric loss tangent is generally in the range of 5 GHz to 50 GHz, such as at least 5 GHz, at least 10 GHz, at least 15 GHz, at least 20 GHz and at most 50 GHz, at most 40 GHz, at most 30 GHz, at most 15 GHz, or at most 10 GHz.

[0079] In some embodiments, the bismaleimide compound has a single C36 hydrocarbyl group. The number of carbon-carbon double bonds can be 0, 1, 2, or 3. An example of such a compound shown below has no carbon-carbon double bonds, but other similar compounds having 1, 2, or 3 carbon-carbon double bonds can also be used. These compounds are formed by the reaction of a diaminodimer with maleic anhydride.

[0080]

[0081] Isomers of any of these compounds can also be used. The above compounds are commercially available under the trade name BMI-689 from Designer Molecules, Inc. (San Diego, CA, USA).

[0082] In other embodiments, the bismaleimide has two or more C36 groups, where each C36 group has 0 to 3 carbon-carbon double bonds. These compounds are generally formed as shown in Reaction Scheme D.

[0083] Reaction Scheme D

[0084]

[0085]

[0086] In this reaction scheme not shown to be in equilibrium, first an excess of the diaminodimer of the formula H 2 N-R 10 -NH 2 is reacted with a compound having two anhydride groups (such as the compound shown as compound (9)) to form an intermediate, namely compound (11). The variable v in compound (11) ranges from 1 to 10, such as 1 to 8, 1 to 6, 1 to 5, 1 to 4, or 1 to 3. Compound (10) is typically a diaminodimer. Thus, each group R 10 is typically a C36 group having 0 to 3 carbon-carbon double bonds (i.e., having 69 to 72 hydrogen atoms). In compound (9), the group Q is any linking group bonded to two anhydride groups. The group Q generally includes at least one aromatic ring.

[0087] In some embodiments, the group Q has a single aromatic ring, and the ring is fused to two anhydride groups, as in compound (9-1).

[0088]

[0089] In other embodiments, group Q comprises two or more aromatic rings, wherein the aromatic group is fused to each maleic anhydride group, as in compounds (9-2), (9-3), and (9-4).

[0090]

[0091]

[0092] Each R 11 and R 12 is independently hydrogen, methyl, or trifluoromethyl.

[0093] The intermediate compound (11) in Reaction Scheme D is then reacted with maleic anhydride to form the bismaleimide compound (13). The bismaleimides formed using compounds (9-1), (9-2), (9-3), and (9-4) are shown below as bismaleimide compounds (13-1) to (13-4).

[0094]

[0095]

[0096] Compound (13-1) is commercially available as BMI-3000 from Designer Molecules, Inc., San Diego, California, USA, where R 10 is a C36 group having 0 carbon-carbon double bonds, and the value of v ranges from 1 to 10 and the average value is typically about 3. Compound (13-2) is commercially available as BMI-1500 from Designer Molecules, Inc., where R 10 is a C 36 H 70 group and the average value of v is about 1.3. Compound (13-4) is commercially available as BMI-1550 from Designer Molecules, Inc. Compound (13-5) is commercially available as BMI-1400 from Designer Molecules, Inc., where v ranges from 1 to 10. Other similar compounds are also available from Designer Molecules, Inc.

[0097] The curable component of the curable mixture usually contains at least 5% by weight, based on the total weight of the curable component, of a bismaleimide compound comprising at least one C36 group having 0 to 3 carbon-carbon double bonds. The curable component includes a poly(norbornene) copolymer, a bismaleimide compound, and a thermal free radical initiator. This amount can be, for example, in the range of 5% to 80% by weight or 5% to less than 80% by weight, based on the total weight of the curable component. This amount can be at least 5% by weight, at least 10% by weight, at least 15% by weight, at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight, or at least 40% by weight, and at most or less than 80% by weight, at most or less than 75% by weight, at most 70% by weight, at most or less than 65% by weight, at most or less than 60% by weight, at most 55% by weight, at most or less than 50% by weight, at most or less than 45% by weight, or at most or less than 40% by weight. Compared with the amounts of many common crosslinking agents used in similar curable compositions, the amount of the bismaleimide used tends to be higher.

[0098] Thermal free radical initiator

[0099] Suitable thermal free radical initiators include various azo compounds, such as those commercially available under the trade name VAZO from Chemours Co. (Wilmington, DE, USA), including VAZO67 (which is 2,2'-azobis(2-methylbutyronitrile)), VAZO 64 (which is 2,2'-azobis(isobutyronitrile)), VAZO 52 (which is 2,2'-azobis(2,4-dimethylvaleronitrile)), and VAZO 88 (which is 1,1'-azobis(cyclohexanecarbonitrile)); various peroxides, such as benzoyl peroxide, cyclohexanone peroxide, lauroyl peroxide, di-tert-amyl peroxide, tert-butyl perbenzoate, dicumyl peroxide, and peroxides commercially available under the trade name LUPERSOL from Atofina Chemical Inc. (Philadelphia, PA, USA) (for example, LUPERSOL 101, which is 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, and LUPERSOL 130, which is 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne); various hydroperoxides, such as tert-amyl hydroperoxide, tert-butyl hydroperoxide, and cumene hydroperoxide; and mixtures thereof.

[0100] The amount of the thermal free radical initiator is generally in the range of 0.01% to 5% by weight based on the total weight of the curable components, which include the polynorbornene copolymer, the bismaleimide compound, and the thermal free radical initiator. The amount can be at least 0.01% by weight, at least 0.05% by weight, at least 0.1% by weight, at least 0.2% by weight, at least 0.5% by weight, or at least 1% by weight, and at most 5% by weight, at most 4% by weight, at most 3% by weight, at most 2% by weight, at most 1% by weight, or at most 0.5% by weight.

[0101] Optional component in the curable composition

[0102] In addition to the curable components, other optional components may also be present in the curable composition. Suitable optional components include, but are not limited to, adhesion promoters, fillers that can be organic materials, inorganic or ceramic materials, or combinations thereof. Suitable optional additives include, but are not limited to, fillers, stabilizers, flow control agents, cure rate retarders, adhesion promoters, impact modifiers, expandable microspheres, glass beads or bubbles, thermal conductive particles, conductive particles, glass, clay, pigments, colorants, antioxidants, etc. Any of these additives can be added in any suitable amount.

[0103] Curable composition and articles containing the curable composition

[0104] The curable composition contains 20% to 95% by weight of the polynorbornene copolymer, 5% to 79.99% (e.g., less than 80%) by weight of the bismaleimide compound, and 0.01% to 5% by weight of the thermal initiator based on the total weight of the curable components in the curable composition. In some embodiments, the curable composition contains 30% to 90% by weight of the polynorbornene copolymer, 10% to 69.99% (e.g., less than 70%) by weight of the bismaleimide compound, and 0.01% to 5% by weight of the thermal initiator based on the total weight of the curable components. In other embodiments, the curable composition contains 40% to 84.5% by weight of the polynorbornene copolymer, 15% to 60% by weight of the bismaleimide compound, and 0.5% to 3% by weight of the thermal initiator. In still other embodiments, the curable composition contains 50% to 80% by weight of the polynorbornene copolymer, 20% to 49% by weight of the bismaleimide compound, and 1% to 3% by weight of the thermal initiator. In yet other embodiments, the curable composition contains 65% to 80% by weight of the polynorbornene copolymer, 20% to 34% by weight of the bismaleimide compound, and 1% to 3% by weight of the thermal initiator.

[0105] In many embodiments, the curable composition is applied as a layer to a suitable first substrate or release liner. If desired, a layer of the curable composition can be applied to the first substrate using roll-to-roll processing. Generally, the curable composition contains an organic solvent that is removed by evaporation at room temperature or at an elevated temperature (such as in the range of 40 degrees Celsius to 120 degrees Celsius).

[0106] After removing any solvent from the curable composition, the layer of curable composition can be rolled up with the first substrate or release liner. Alternatively, a second substrate can be positioned adjacent to the second surface of the curable composition layer that faces away from the first substrate. In some embodiments, both the first substrate and / or the second substrate are selected such that the curable composition does not adhere firmly and each substrate can be removed later. In some embodiments, the curable composition is positioned between two different substrates and then rolled up. Although both substrates can be removed later, the adhesion strength to the two substrates is typically selected to be different such that one substrate is easier to remove than the other.

[0107] Any suitable substrate can be used as the above-described first substrate or second substrate. These substrates can be flexible or non-flexible and can be conductive or non-conductive. The substrate can be formed from a polymeric material, glass, ceramic material, metal (including various alloys), or combinations thereof. In some embodiments, the substrate is glass, ceramic material, or metal. Suitable polymeric materials can be selected from polymeric films or plastic composites (e.g., glass or fiber-filled plastics). The polymeric material can be prepared, for example, from polyolefins (e.g., polyethylene, polypropylene, or their copolymers), polyurethanes, polyvinyl acetate, polyvinyl chloride, polyesters (ethylene glycol terephthalate or polyethylene naphthalate), polycarbonates, poly(methyl)methacrylate (PMMA), ethylene-vinyl acetate copolymers, and cellulose materials (e.g., cellulose acetate, cellulose triacetate, and ethyl cellulose). If desired, the non-conductive substrate can be coated with a conductive layer.

[0108] Release liners can be used to fabricate articles and serve as temporary substrates. That is, the release liner is replaced with a permanent substrate. Suitable release liners generally have a low affinity for the curable composition. Exemplary release liners can be prepared from paper materials (e.g., kraft paper) or other types of polymeric materials. Some release liners are coated with an outer layer of a release agent that is a material such as a silicone-containing material or a fluorocarbon-containing material (e.g., polyfluoropolyether or polytetrafluoroethylene).

[0109] Cured composition

[0110] A cured composition is formed by heating the curable composition at a temperature sufficient to crosslink the polynorbornene copolymer with the bismaleimide compound. Suitable temperatures are generally in the range of 150 to 200 degrees Celsius.

[0111] If the curable composition is in the form of a roll, the roll is generally unwound and the curable composition is heated to crosslink the polynorbornene copolymer with the bismaleimide compound. If a single substrate is present, the substrate can be present during the curing process for support. The single substrate can be thermally laminated to the cured composition or can be removable leaving a cured film. Alternatively, the curable composition can be separated from the first substrate and positioned adjacent to another substrate (e.g., a third substrate) prior to curing and thermally laminated to the third substrate during the curing process.

[0112] If two substrates (e.g., a first substrate and a second substrate) are present in the roll, one substrate (the first substrate) is generally removed prior to curing or prior to positioning the curable composition adjacent to another substrate (i.e., the third substrate). If the curable composition is positioned adjacent to the third substrate, the second substrate can be removed after positioning the curable composition and prior to curing. If the curable composition is not positioned adjacent to the third substrate, curing generally occurs while the curable composition is in contact with the second substrate. In such embodiments, the second substrate can be removed after curing to provide a film of the cured composition.

[0113] The cured composition can be used, for example, in integrated encapsulation spaces. The cured film can have a combination of desired properties such as a high glass transition temperature (e.g., greater than 110 degrees Celsius or greater than 120 degrees Celsius and up to 300 degrees Celsius or up to 275 degrees Celsius), a low coefficient of thermal expansion between 0 degrees Celsius and 100 degrees Celsius (e.g., less than 100 ppm for an unfilled system); a low dielectric constant (e.g., Dk less than 2.5) and a low dielectric loss tangent (Df less than 0.004).

[0114] Examples

[0115] Unless otherwise specified or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight. Table 1 below lists the materials used in the examples and their sources.

[0116] Table 1. Material table

[0117]

[0118]

[0119] Test method

[0120] Size exclusion chromatography (SEC)

[0121] The average molecular weight of each polynorbornene copolymer in the polynorbornene copolymer was measured using size exclusion chromatography (SEC). The SEC apparatus consisted of a 1260 Infinity II liquid chromatography system (comprising an isocratic pump, an autosampler, a column oven, and a variable wavelength UV / visible light detector) obtained from Agilent Technologies (Santa Clara, CA), which was operated at a flow rate of 1.0 mL / minute. The SEC column set consisted of two PLgel 5um MIXED-C (300 millimeters (mm) long x 7.5 mm inner diameter) and a PLgel 5um guard column (50 millimeters (mm) long x 7.5 mm inner diameter), both of which were obtained from Agilent Technologies. The detection was composed of a mini-DAWN 3-angle light scattering detector and an OPTILAB differential refractive index detector, both of which were obtained from Wyatt Technology Corporation (Santa Barbara, CA). Data was collected and analyzed using software ASTRA version 8 obtained from Wyatt Technology Corporation. The column oven, UV / vis detector, and differential refractive index detector were set to 40 °C. The solvent and eluent (or mobile phase) consisted of OMNISOLV grade tetrahydrofuran (stabilized with 250 ppm of butylated hydroxytoluene) obtained from EMD Millipore Corporation of Burlington, Massachusetts. Briefly, the polymer solution was prepared by dissolving approximately 50 mg of the polymer in 10 mL of the eluent tetrahydrofuran, aiming for a polymer solution concentration of 5 mg / mL. The polymer solution was loaded into the SEC apparatus using an autosampler and an injection volume of 50 microliters. Using the signal from the OPTILAB differential refractive index detector and a dn / dc value of 0.1300, the number average molecular weight (M n ), weight average molecular weight (M w ), and polydispersity index

[0122] Dynamic mechanical analysis (DMA)

[0123] Dynamic mechanical analysis was performed on a TA Instruments RSA-G2 (TA Instruments, Eden Prairie, MN) using a temperature ramp at constant strain with the following method steps: 1) Equilibrate at -30 °C; 2) Ramp at 3 °C / min to 300 °C. Parameters: Sampling interval 10 s / pt; Strain = 0.1%. For each film sample to be tested, a rectangular piece was cut out (approximate dimensions: 6.5 mm × 50 mm, thickness recorded separately). The gas used for the purge, heating, and cooling chambers was nitrogen.

[0124] Thermomechanical analysis (TMA)

[0125] Thermal mechanical analysis was performed on a TA Instruments Q400 TMA using a temperature ramp with the following method steps: 1) Equilibrate at -20 °C; 2) Isothermal for 2 min; 3) Ramp at 2 °C / min to 300 °C, 4) Isothermal for 2 min; 5) Ramp at 2 °C / min to -20 °C, 6) Ramp at 2 °C / min to 300 °C; 7) Isothermal for 2 min. Probe: Auger; Preload force = 0.250 N. For each film sample to be tested, a rectangular piece was cut out (approximate dimensions: 6.5 mm × 9.0 mm, thickness recorded separately). The coefficient of thermal expansion (CTE) was obtained by examining the slope of the dimensional change curve relative to temperature and expressed as a ppm / °C value. This CTE data was obtained only from the second heating cycle (step 6 from the above method). The gas used for the purge, heating, and cooling chambers was nitrogen.

[0126] Separation column dielectric resonator measurement

[0127] All split-post dielectric resonator measurements were performed at 10.1 GHz and 25 °C according to the standard IEC 61189-2-721. Each material was inserted between two fixed dielectric resonators. The resonant frequency and quality factor of the post are affected by the presence of the sample, and this enables the direct calculation of the complex permittivity (permittivity and dielectric loss). The geometry of the split dielectric resonator fixture used in our measurements was designed by Company QWED, Warsaw, Poland. These resonators operate in the TE01d mode with only an azimuthal electric field component, such that the electric field remains continuous across the dielectric interface. The split-post dielectric resonator measures the permittivity component in the plane of the sample. Ring coupling (critical coupling) was used in each of these dielectric resonator measurements. This split-post resonator measurement system was combined with a Keysight VNA (Vector Network Analyzer model PNA N5222B and millimeter wave test set model N5292A, 900 Hz - 110 GHz). Calculations were performed with the commercial analysis split-post resonator software from Company QWED to provide a powerful measurement tool for determining the complex permittivity of each sample at the test frequency, which was 10 GHz.

[0128] Integrated process

[0129] 1-(Bicyclo[2.2.1]hept-5-en-2-ylmethyl)-3,4-dimethyl-1H-pyrrole-2,5-dione (DMMAlNB) Preparation

[0130]

[0131] This method is adapted from the method given in Example M1 of U.S. Patent 8,053,515 (Elce et al.). A 500 ml two-necked round bottom (2NRB) flask was equipped with magnetic stirring, oil bath heating, and a dropping funnel. The flask was charged with 22.6 g (0.18 mol) of dimethyl maleic anhydride and 200 ml of toluene, and then immersed in an oil bath at 35 °C. The anhydride dissolved completely to give a clear solution. Under a nitrogen seal, 22.2 g (0.18 mol) of 5-norbornene-2-methylamine was added via the addition funnel with stirring. A colorless solid immediately began to precipitate with the first drop of amine. The vial containing the amine charge was washed with two 10 ml portions of toluene, which were also transferred to the addition funnel and added dropwise to the reaction mixture. After the addition was complete, the reaction mixture was a solid mass, although the stir bar was still turning. The flask was transferred to an 80 °C oil bath, the addition funnel was replaced with a Dean-Stark (DS) trap with a reflux condenser on top, and the oil bath temperature was ramped to 140 °C (set point). Toluene reflux began after about 30 min, and the reaction mass began to decompose. Reflux was continued for 6 h, then the oil bath temperature was lowered to 75 °C, and the apparatus was left overnight. Upon return, about 3.2 g (99% yield) of water was recovered from the trap, including large droplets adhering to the trap walls. The apparatus was disassembled, the flask was removed from the oil bath and allowed to cool after capping with a glass stopper. The toluene solution of the crude reaction mixture was washed twice with 50 mL portions of 1 M KOH solution to remove traces of the starting anhydride, and then washed four times with deionized water. The solution was dried over anhydrous MgSO 4 and filtered through Whatman #4 filter paper into a 1 L round bottom (RB) flask. The solvent was removed by rotary evaporation, followed by a nitrogen purge to leave 37.7 g of a crude product as a light brown liquid. 36.4 g of this material was vacuum distilled using a Kugelrohr apparatus in a 250 ml Microware RB flask at 140 °C to 165 °C and 1 torr to 2 torr, giving 36.2 g (isolated yield 87%) of a clear colorless distillate. CDCl 3 in solution 1 H and 13 C NMR spectra showed that the distillate had extremely high purity, with no visible non-solvent-related peaks other than those assigned to the desired product.

[0132] Preparation of catalyst solution C1

[0133] As described in the synthesis procedure of polymer P3, the following components were combined in a small glass wide-mouth bottle with a magnetic stir bar and stirred at room temperature for at least 30 minutes, and then added to the reaction mixture: 68.7 milligrams (mg) of Pd(iDipp)(allyl)Cl, 67.3 mg of PCy 3, 531.7 mg of Na(BArF) 4 and 75.36 grams (g) of DCE.

[0134] Preparation of catalyst solution C2

[0135] As described in the synthesis procedures of polymers P1, P2, P4, P5, P6, P7, and P8, the following components were combined in a 25 mL screw-cap glass wide-mouth bottle with a magnetic stir bar and stirred at room temperature for at least 30 minutes, then added to the reaction mixture: 23.1 milligrams (mg) of Pd(iDipp)(allyl)Cl, 22.9 mg of PCy 3 , 177.9 mg of Na(BArF) 4 and 25.30 grams (g) of DCE. For the synthesis procedures other than polymer P3, an appropriate amount of catalyst solution C2 was prepared using the same molar ratio of catalyst components and method such that once added to the monomer solution, the molar ratio of the total norbornene-type monomer to palladium was 5000 to 1.

[0136] Preparation of copolymer P1

[0137] Charge ENB (2.40 g, 17.6 mmol), DNB (42.20 g, 180.0 mmol), 1-octene (22.44 g, 200.0 mmol), and toluene (87.77 g, 952.6 mmol) into a 500 mL three-necked round-bottom reactor. The reactor was equipped with a reactor head with a nitrogen inlet, an overhead mechanical stirring device (glass rod and PTFE paddle), and one port was sealed with a rubber septum. The assembly was placed in a water bath equilibrated to 23 °C, stirred at 400 rpm, and purged with nitrogen for 30 minutes. The catalyst solution C2 was rapidly added to the reaction mixture via a 20 mL polypropylene syringe with an 18-gauge needle. The reaction was stirred for 24 hours. After this time, the mixture had developed significant viscosity and had become translucent brown. The 11H NMR analysis showed that all the reactive double bonds of the monomers had disappeared. The reaction mixture was slowly poured into a 4000 mL beaker containing approximately 2000 mL of MEK under mechanical stirring. As the mixture was poured, white filamentous polymer precipitated. After all the reaction solution was added, the precipitated solid was broken up and cut with scissors to aid stirring. The polymer was stirred for at least two hours to completely precipitate from the reaction solution. The polymer was separated by vacuum filtration using a Buchner funnel and filter paper. The separated polymer solid was dried in an open aluminum dish at ambient temperature for at least 18 hours and then in a forced air oven at 90 °C for 2 hours. The isolated yield of polymer P1 was 44.34 g (yield based on the total norbornene-type monomers added was 99.42%). The weight average molecular weight was 403.8 kg / mol and the polydispersity index was 2.80.

[0138] Preparation of copolymer P2

[0139] In the same manner as polymer P1, using HNB (32.10 g, 180.0 mmol), DMMAINB (4.64 g, 20.1 mmol), 1-octene (22.44 g, 200.0 mmol), toluene (106.20 g, 1152.6 mmol), and catalyst solution C2 containing 23.9 milligrams (mg) of Pd(iDipp)(allyl)Cl, 22.7 mg of PCy 3 and 177.2 mg of Na(BArF) 4 and 25.30 grams (g) of DCE, polymer was synthesized. Due to the slower reaction of the DMMAINB monomer, the polymerization was allowed to proceed for 48 hours before precipitation. The separation and drying of the polymerization product were completed as in polymer P1. The isolated yield of polymer P2 was 26.78 g (yield based on the total norbornene-type monomers added was 72.93%). The weight average molecular weight was 251.7 kg / mol and the polydispersity index was 2.02.

[0140] Preparation of copolymer P3

[0141] The following components were added to a 1000 mL multi-neck reaction vessel equipped with an overhead mechanical stirrer: NB (25.42 g, 270 mmol), DNB (63.29 g, 270 mmol), ENB (7.21 g, 60 mmol), 67.33 g of 1-octene, and 294.46 g of toluene. The headspace of the vessel was flushed with nitrogen for 5 minutes, after which 76.02 g of catalyst solution C1 was added via pipette. The vessel was capped and stirred at room temperature for 20.5 hours. After this time, the mixture had developed significant viscosity and had become translucent brown. The 11H NMR analysis showed that almost all of the reactive double bonds of the monomers had disappeared. With magnetic stirring, half of the reaction mixture was slowly poured into a 4000 mL beaker containing approximately 2000 mL of MEK. As the mixture was poured, white filamentous polymer precipitated. Periodically, the filaments were broken up and cut with scissors to aid stirring. During this process, more MEK was added until the total volume was approximately 3000 mL. The pouring / stirring / cutting process was repeated for the other half of the reaction mixture. The polymer filaments obtained from this process were washed three times with fresh MEK on a glass filter frit and placed in an aluminum tray. The filaments were dried in an oven at 90 °C for 2 hours. The isolated yield of polymer P3 was 91.20 g (yield based on the total norbornene-type monomers added was 95.08%). The weight-average molecular weight was 411.1 kg / mol, and the polydispersity index was 7.07.

[0142] Preparation of copolymer P4

[0143] In the same manner as for polymer P1, using HNB (16.07 g, 90.13 mmol), NB (8.47 g, 90.0 mmol), DMMAINB (4.63 g, 20.0 mmol), 1-octene (22.44 g, 200.0 mmol), toluene (110.67 g, 1201.1 mmol), and catalyst solution C2 containing 22.9 milligrams (mg) of Pd(iDipp)(allyl)Cl, 22.7 mg of PCy 3 、177.2 mg of Na(BArF) 4 and 13.73 grams (g) of DCE to synthesize the polymer. Due to the slower reaction of the DMMAINB monomer, the polymerization was allowed to proceed for 48 hours before precipitation. The isolation and drying of the polymerization product were completed as in polymer P1. The isolated yield of polymer P4 was 25.36 g (yield based on the total norbornene-type monomers added was 87.00%). The weight-average molecular weight was 300.8 kg / mol, and the polydispersity index was 2.80.

[0144] Preparation of copolymer P5

[0145] In the same manner as for polymer P1, using DNB (42.20 g, 180.0 mmol), NB (1.88 g, 20.0 mmol), 1-octene (22.44 g, 200.0 mmol), toluene (87.77 g, 952.6 mmol), and catalyst solution containing 23.1 milligrams (mg) of Pd(iDipp)(allyl)Cl, 22.9 mg of PCy 3 、177.9 mg of Na(BArF) 4A catalyst solution C2 of 25.08 g of DCE was used to synthesize the polymer. The polymerization was carried out for 24 hours before precipitation. The separation and drying of the polymerization product were completed as in polymer P1. The separation yield of polymer P5 was 44.04 g (yield based on the total norbornene-type monomers added was 99.91%). The weight-average molecular weight was 267.2 kg / mol, and the polydispersity index was 3.48.

[0146] Preparation of copolymer P6

[0147] In the same manner as polymer P1, DNB (52.74 g, 225.0 mmol), ENB (9.01 g, 75.0 mmol), 1-octene (33.67 g, 300.0 mmol), toluene (140.63 g, 1526.3 mmol), and a catalyst solution C2 containing 22.9 mg of Pd(iDipp)(allyl)Cl, 34.2 mg of PCy 3 、293.9 mg of Na(BArF) 4 and 25.30 g of DCE were used to synthesize the polymer. The polymerization was carried out for 22 hours before precipitation. The separation and drying of the polymerization product were completed as in polymer P1. The separation yield of polymer P6 was 61.69 g (yield based on the total norbornene-type monomers added was 99.89%). The weight-average molecular weight was 405.2 kg / mol, and the polydispersity index was 2.49.

[0148] Preparation of copolymer P7

[0149] In the same manner as polymer P1, VNB (30.05 g, 250.0 mmol), HNB (44.62 g, 250.3 mmol), 1-octene (112.22 g, 1000.1 mmol), toluene (204.60 g), and a catalyst solution C2 containing 57.5 mg of Pd(iDipp)(allyl)Cl, 57.5 mg of PCy 3 、443.3 mg of Na(BArF) 4 and 26.52 g of DCE were used to synthesize the polymer. The polymerization was carried out for 22 hours before precipitation. The separation and drying of the polymerization product were completed as in polymer P1. The separation yield of polymer P7 was 64.32 g (yield based on the total norbornene-type monomers added was 86.14%). The weight-average molecular weight was 116.9 kg / mol, and the polydispersity index was 2.35.

[0150] Preparation of copolymer P8

[0151] In the same manner as for Polymer P1, use VNB (30.05 g, 250.0 mmol), DNB (58.62 g, 250.1 mmol), 1-octene (112.22 g, 1000.1 mmol), toluene (191.01 g), and catalyst solution C2 containing 57.2 milligrams (mg) of Pd(iDipp)(allyl)Cl, 56.1 mg of PCy 3 , 443.1 mg of Na(BArF) 4 and 25.30 grams (g) of DCE to synthesize the polymer. Allow the polymerization to proceed for 22 hours before precipitation. Separate and dry the polymerization product as in Polymer P1. The isolated yield of Polymer P8 is 87.97 g (yield based on the total norbornene-type monomers added is 99.21%). The weight-average molecular weight is 155.6 kg / mol, and the polydispersity index is 2.84.

[0152] Examples EX1 to EX13 and Comparative Examples CE1 to CE5: Preparation, curing and analysis of films

[0153] The glass wide-mouth bottle is equipped with a stir bar and charged with the amounts of materials shown in Table 2 below. Cap the resulting solution and stir at room temperature for 16 to 24 hours.

[0154]

[0155] Cast films from all the solutions from Table 2 (except CE4 and CE5, see the following description) as follows. Pour approximately 35 g of the solution into a round glass dish (90 mm in diameter, 18 mm in depth). Leave the dish uncovered in a passive fume hood at room temperature for at least 48 hours. During this time, most or all of the toluene evaporates. Dry the resulting solid film at 70 °C for one hour. Cut out the flat central portion of each dried film and perform the general procedure for thermal curing of the films described below. The appearance and thickness of some of the film samples before and after thermal curing are recorded in Table 3.

[0156] The general procedure for thermal curing of the films is carried out as follows. Sandwich the film samples between polytetrafluoroethylene (PTFE) sheets, and then sandwich these sheets between flat steel plates. Heat these sandwich constructs in a nitrogen-purged furnace using the following temperature profile: Step 1) Ramp from room temperature to 200 °C at 5 °C / min; Step 2) Hold at 200 °C for two hours; and Step 3) Turn off the heat and allow it to return to room temperature. For CE4 and CE5, the procedure is slightly modified as described below.

[0157] Pour the CE4 solution (8.63 g) into a shallow rectangular PTFE mold (85 millimeters (mm) × 34 mm × 4 mm) and allow the mold to dry at room temperature for 7 days, leaving a viscous liquid layer. According to the general procedure for the thermal curing of the film, the viscous liquid layer was thermally cured in an oven, except that the viscous liquid layer was not placed in a sandwich structure but baked in the same PTFE mold.

[0158] Pour the CE5 solution (about 35 g) into a round glass dish (90 mm in diameter, 18 mm deep). Allow the dish to stand uncovered in a passive fume hood at room temperature for at least 48 hours. After this time, the material is not a self-supporting film but a tough waxy solid with small crystals. Place the dish and its contents directly into a furnace purged with nitrogen and process with the same temperature profile as described in the general procedure for the thermal curing of the film.

[0159] Table 3. Appearance and thickness of film samples 。

[0160]

[0161]

[0162] Evaluate the cured film samples from above using the dynamic mechanical analysis method described above. The storage modulus (E') results are shown in Table 4 below. Calculate the Tg by recording the peaks in the tan(δ) curve.

[0163] Table 4. Results of DMA tests

[0164]

[0165] CE3 (formed using P3 and DCP as a crosslinking agent) was compared with its maleimide-enhanced counterparts EX3, EX5, and EX6, and the storage modulus ratio at 30 °C and 225 °C was significantly lower when bismaleimide was used for crosslinking. The lower value of this ratio indicates that the material better maintains its strength and integrity at higher temperatures (even above the glass transition temperature). Maintaining integrity at high temperatures is one of the desirable aspects of thermosetting materials. CE1 is also a bismaleimide-enhanced formulation of P3, and it also has a low storage modulus ratio. However, CE1 is not a desirable material because the lack of the high aromaticity of BMI-1971 without the C36 group results in poor compatibility with P3 (see the large amount of haze and crystals observed for CE1 in Table 3). CE4 (simply BMI-689 + DCP, without a norbornene copolymer) is a liquid in the uncured state and is a very brittle material when cured; these are all undesirable properties.

[0166] Comparing CE2, which contains no crosslinkable groups in the polymer (P5), with analogs having crosslinkable groups (EX1, EX3, and EX4), the presence of the crosslinkable groups along the polymer together with the added BMI results in cured materials with higher modulus and higher glass transition temperature. Additionally, the modulus at temperatures above T g such as E' at 225 °C indicates that a higher crosslink density is achieved with the polymerizable groups in the polymer.

[0167] Thermomechanical analysis (TMA) was performed on the cured film samples from above, and the results are shown in Table 5.

[0168] Table 5. TMA test results

[0169]

[0170] *These samples were tested using the same instrument as described in the TMA test, but the method was slightly different: 1) Equilibrate at -20 °C; 2) Isothermal for 2 min; 3) Ramp at 2 °C / min to 200 °C, 4) Isothermal for 2 min; 5) Ramp at 2 °C / min to -20 °C, 6) Ramp at 2 °C / min to 200 °C; 7) Isothermal for 2 min.

[0171] **The dimensional change curve with respect to temperature in this region is non-linear or pseudo-linear, so useful values cannot be obtained.

[0172] Comparing CE3 (P3 + DCP) with its maleimide-enhanced counterparts EX3, EX5, and EX6, the CTE is significantly lower when BMI-689 is included, slightly lower when BMI-1500 is included, but similar when BMI-3000 is included. Similar to what was seen in the DMA results above, CE1 appears to have an attractive low CTE, but its lack of uniformity makes it undesirable.

[0173] Similarly, CE4 has a relatively low CTE value, but its liquid uncured state and brittle cured state are undesirable.

[0174] Comparing CE2, which contains no crosslinkable groups in the polymer (P5), with analogs having crosslinkable groups (EX1, EX3, and EX4), the presence of the crosslinkable groups along the polymer seems to result in a decrease in the CTE of the polymer below Tg compared to the non-crosslinkable control polymer. Increasing the content of the crosslinkable monomer in EX7 also decreased the CTE of the observed cured material.

[0175] Comparing CE5, which has a very high level of bismaleimide resin and a very low amount of polynorbornene polymer, with all of EX1 to EX13, which have lower amounts of bismaleimide resin and higher amounts of polynorbornene polymer, reveals the advantages of the example compositions. CE5 does not form a self-supporting film in the uncured state and produces a film with a very low Tg in the cured state, both of which are undesirable.

[0176] The data in Table 6 were obtained for the listed examples and comparative examples using the above-described separation column dielectric resonator measurement procedure.

[0177] Table 6. Results of dielectric tests at 10.1 GHz 。

[0178]

Claims

1. A curable composition, the curable composition comprising a curable component, the curable component comprising: a) An addition-polymerized polynorbornene copolymer having norbornene-based monomer units containing crosslinkable pendant groups; and b) A bismaleimide compound in an amount in the range of 5% to less than 80% by weight based on the total weight of the curable component, wherein the bismaleimide compound has (1) two bismaleimide groups and (2) at least one C36 hydrocarbon group having 0 to 3 carbon-carbon double bonds; and c) A thermal free radical initiator.

2. The curable composition according to claim 1, wherein the addition-polymerized polynorbornene copolymer further comprises norbornene-based monomer units having pendant alkyl groups, norbornene monomer units having no pendant groups, or a combination thereof.

3. The curable composition according to claim 2, wherein the addition-polymerized polynorbornene copolymer comprises 2 mol% to 80 mol% of the norbornene-based monomer units having crosslinkable pendant groups, 20 mol% to 90 mol% of the norbornene-based monomer units having pendant alkyl groups, and 0 mol% to 30 mol% of the norbornene monomer units having no pendant groups.

4. The curable composition according to any one of claims 1 to 3, wherein the norbornene-based monomer units having crosslinkable pendant groups are derived from a monomer of formula (I-A) or (I-B) 5. The curable composition according to any one of claims 1 to 3, wherein the monomer units having crosslinkable pendant groups are derived from a monomer of formula (II) wherein R 3 may be a (hetero)alkylene group; and Each group R 4 is hydrogen or methyl.

6. The curable composition according to any one of claims 1 to 5, wherein the bismaleimide compound is formed by reacting a C36 diamine having 0 to 3 carbon-carbon double bonds with maleic anhydride.

7. The curable composition according to any one of claims 1 to 5, wherein the bismaleimide compound has at least two C36 hydrocarbon groups each having 0 to 3 carbon-carbon double bonds and being aliphatic.

8. The curable composition according to claim 7, wherein the bismaleimide compound is formed by reacting a C36 diamine having 0 to 3 carbon-carbon double bonds with a dianhydride and then with maleic anhydride.

9. The curable composition according to claim 7 or 8, wherein the bismaleimide compound is selected as a compound of one of the following formulas wherein Each R 10 is a C36 group having from 0 to 3 carbon-carbon double bonds; Each R 11 and R 12 is independently hydrogen, methyl or trifluoromethyl; and v is a number in the range of 1 to 10.

10. The curable composition according to any one of claims 1 to 9, wherein the curable composition is positioned as a layer adjacent to a substrate.

11. A cured composition, the cured composition comprising the cured reaction product of the curable composition according to any one of claims 1 to 10 after exposure to a temperature sufficient to activate the thermal initiator.

12. The cured composition according to claim 11, wherein the glass transition temperature (Tg) of the cured composition is greater than 110 degrees Celsius.

13. The cured composition according to claim 11 or 12, wherein the dielectric constant of the cured composition is less than 2.5 and / or the tangent of the dielectric loss angle at 10 GHz is less than 0.004.

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