Cyclic Diene Copolymer

Abstract

To provide copolymers formed by cationic polymerization of one or more cyclic dienes and a comonomer selected from the group consisting of a monoterpene, a branched styrene, and combinations thereof, in the presence of a catalyst.SOLUTION: Random copolymers having repeat units derived from a cyclic conjugated diene, such as 1,3-cyclohexadiene, and a comonomer, such as a monoterpene, can be prepared as soluble products in hydrocarbon solvents. The copolymers can be crosslinked with various crosslinking agents to form materials having good oxidative stability and fire retardancy. The uncrosslinked and crosslinked copolymers have useful properties such as a low dielectric dissipation factor, low dielectric constants, and a good balance of thermomechanical and electrical properties that make them valuable in electronic applications.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to cyclic diene-based polymers, methods for making the polymers, and their uses. [Background technology]

[0002] Over the past half century, low-dielectric materials possessing numerous electrical, thermal, chemical, and mechanical properties have been intensively studied by ceramic and polymer scientists. Applications of low-dielectric constant materials often depend on these properties, and the selection of a low-dielectric material can significantly impact device performance and lifetime. Rapid developments in the microelectronics industry have also created ever-increasing demands for more advanced methods and materials for such applications. The trend toward miniaturization of electronic components has also fueled the search for dielectric materials with optimal electrical and functional performance characteristics, such as desirable combinations of electrical, thermal, chemical, adhesion, and mechanical properties. Summary of the Invention [Problem to be solved by the invention]

[0003] Thus, there is a continuing need for polymeric materials that have desirable properties for electronic applications, such as high hydrolytic stability, very low moisture absorption, good processability, high glass transition temperature (Tg), low density, and excellent dielectric properties. [Means for solving the problem]

[0004] (Abstract) In one embodiment, a copolymer is disclosed. The copolymer is formed by cationic polymerization of one or more cyclic dienes with a comonomer selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof in the presence of a catalyst. The comonomer is selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof. The cyclic diene is selected from the group consisting of 1,3-cyclohexanediene (CHD), cyclopentadiene (CPD), 1,3-cycloheptadiene, 4,5,6,7-tetrahydroindene, norbornadiene (NBD), and combinations thereof. The catalyst is selected from the group consisting of Bronsted acids, Lewis acids, and combinations thereof. The copolymer has an Mn of 300 to 5,000 daltons and an Mz of 2,000 to 25,000 daltons. The copolymer has a solubility in a hydrocarbon solvent of 0.1 to 2 g of copolymer per gram of hydrocarbon solvent, and a Tg of 80°C to 180°C.

[0005] In another aspect, a method for forming a copolymer is disclosed. The method includes cationic polymerization of one or more cyclic diene-containing monomers and comonomers in a hydrocarbon solvent in the presence of a catalyst to form the copolymer, and isolating the copolymer. The comonomers are selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof, and the catalyst is selected from the group consisting of Bronsted acids, Lewis acids, and combinations thereof.

[0006] Other aspects of the present disclosure include the use of crosslinked polymers formed by reaction of the above copolymers with a crosslinking agent and non-crosslinked copolymers to form prepregs for electronic applications. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a plot showing the change in Tg of a crosslinked copolymer resin as a function of mole % C═C present in pre-crosslinked copolymer resin (B) made with CHD and alpha pinene in a 50:50 weight ratio, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following terms are used throughout this specification:

[0009] M w , the weight average molecular weight is

[0010]

number

[0011] M n teeth,

[0012]

number

[0013] M z teeth,

[0014]

number

[0015] The polydispersity index (PDI) is PDI=M w / M n is calculated according to

[0016] Cup and Ball (C&B) SP (Softening Point) can be determined by ASTM E28 or Cup and Ball (C&B) Softening Point Test or ASTM D 6090 Cup and Ball.

[0017] The glass transition temperature (Tg) of a resin can be determined according to ASTM D 6604 from 0°C to 200°C using a heating rate of 10°C / min.

[0018] "Cyclic diene" refers to a cyclic compound having two double bonds. If the two double bonds form a conjugated system, the cyclic diene is called a "cyclic conjugated diene." "Cyclic diene" includes both cyclic non-conjugated dienes and cyclic conjugated dienes.

[0019] The dielectric loss tangent (Df) is defined as the rate of electrical energy loss in a dissipative system.

[0020] Dielectric constant (Dk) is defined as the ability of a material to store electrical energy in an electric field.

[0021] The copolymers, methods of forming them, and uses of the copolymers are further described in more detail below.

[0022] Copolymers: Copolymers formed by cationic polymerization of one or more cyclic dienes and comonomers in the presence of a catalyst have repeat units derived from the cyclic diene and the comonomer.

[0023] In embodiments, the cyclic diene comprises one or more cyclic conjugated dienes, one or more cyclic non-conjugated dienes, or a combination thereof. Non-limiting examples of cyclic conjugated dienes include 1,3-cyclohexadiene (CHD), cyclopentadiene (CPD), 1,3-cycloheptadiene, 4,5,6,7-tetrahydroindene (THI), and combinations thereof. Non-limiting examples of cyclic non-conjugated dienes include norbornadiene (NBD), 1,5-cyclooctadiene, dicyclopentadiene, and combinations thereof. In embodiments, the cyclic diene is selected from CHD, CPD, 1,3-cycloheptadiene, THI, NBD, and combinations thereof.

[0024] In an embodiment, the cyclic diene is 1,3-cyclohexadiene containing up to 10 wt.% of 1,4-cyclohexadiene, based on the total weight of the cyclic dienes. The use of 1,3-cyclohexadiene containing small amounts of 1,4-cyclohexadiene can be advantageous because it avoids the need for cumbersome separation of the 1,3- and 1,4-isomers.

[0025] The comonomer may be one or more members selected from monoterpenes, branched styrenes, and combinations thereof. The monoterpenes may be C 10 H 16 In embodiments, the monoterpene is selected from α-pinene, β-pinene, limonene, myrcene, ocimene, α-phellandrene, β-phellandrene, farnesene, camphene, α-terpinene, sabinene, γ-terpinene, α-terpinene, 3-carene, and combinations thereof.

[0026] The comonomer may also be of formula (III) having a substituent R, such as an alkyl group, at the C-2 carbon of the olefinic group that is inert to the cationic polymerization conditions.

[0027] [ka] The branched styrene compound may be:

[0028] In embodiments, when a cyclic conjugated diene undergoes cationic polymerization, the product may contain both 1,2- and 1,4-addition units derived from the diene. The 1,4-addition is generally preferential over the 1,2-addition. For example, 1,3-cyclohexadiene undergoes cationic polymerization to produce a major amount of 1,4-addition units (Formula I) and a minor amount of 1,2-addition units (Formula II).

[0029] [ka] This results in:

[0030] The relative ratio of 1,4- to 1,2- can be varied by varying the catalyst and reaction conditions. In embodiments, the copolymer comprises 1,4- and 1,2-addition units of the cyclic conjugated diene in a relative molar ratio of 90:10 to 10:90, or 50:50, or 30:70 to 70:30, or 40:60 to 60:40, or 20:80 to 80:20.

[0031] Copolymers having a wide range of relative molar ratios of cyclic diene to comonomer can be obtained, such as 5:95 to 95:5, respectively. In embodiments, copolymers formed by polymerizing 1,3-cyclohexadiene and comonomer have relative molar ratios of cyclic diene to comonomer ranging from 5:95 to 95:5, or 50:50, or 30:70 to 70:30, or 40:60 to 60:40, or 20:80 to 80:20.

[0032] Preparation of Copolymers: The copolymers may be prepared by cationic polymerization of one or more cyclic dienes and comonomers in a suitable solvent in the presence of a catalyst.

[0033] Hydrocarbon solvents are preferred because they are generally inert to the catalyst and the cationic intermediates produced during polymerization. Suitable hydrocarbon solvents include aromatic hydrocarbons, alicyclic hydrocarbons, or aliphatic hydrocarbons, and combinations thereof. Non-limiting examples include hexane, heptane, alkylbenzene, limonene, turpentine, octane, isooctane, cyclohexane, varnish and paint naphtha (VM and P naphtha), petroleum ether, toluene, xylene, and mixtures thereof.

[0034] The catalyst can broadly be a Bronsted acid, a Lewis acid, or a combination thereof. The catalyst may be Bronsted acid type, Lewis acid type, or may have both Bronsted acid type catalytic activity and Lewis acid type catalytic activity. In embodiments, the catalyst comprises a supported Bronsted acid, an unsupported Bronsted acid, a Lewis acid, precursors thereof, or combinations thereof. Various non-limiting classes of catalysts can be used, including organic acids, organic sulfonic acids, organic-inorganic acids, acidic zeolites, any Lewis acid based on metals from Groups 3-11 and 12-15 of the Periodic Table of the Elements, and mixtures thereof.

[0035] Non-limiting examples include sulfuric acid, phosphoric acid, hypophosphorous acid, polyphosphoric acid, heteropolyacids such as phosphotungstic acid and silicotungstic acid, 2,2,3-trichlorobutyric acid, 2,5-dichlorobenzenesulfonic acid, chlorosulfonic acid, methanesulfonic acid, p-toluenesulfonic acid, triflic acid, benzenesulfonic acid, 2,5-dichlorobenzenesulfonic acid, beta-naphthol-3,6,8-trisulfonic acid, sulfosalicylic acid, p-toluidine-m-sulfonic acid; sulfonated solid acid derivatives such as sulfonated styrene-divinylbenzene, sulfonated silica, sulfonated fluoropolymers, and polystyrene-supported sulfonic acid; amorphous silica-alumina having a silica content of 0.1% to 99.9% and / or a pore size of 0.1 ml / g to 5 ml / g and / or a viscosity of 100 to 1000 m 2 / g surface area (BET) and calcined at temperatures between 200°C and 1000°C; phyllosilicates such as natural or synthetic clays from the kaolin family such as kaolinite, halloysite, dickite, etc., or from the smectite family such as montmorillonite, nontronite, hectorite, saponite, etc., or from the illite / mica family such as glauconite, muscovite, paragonite, etc., or from the chlorite family such as chamosite, kookite, nimite, etc., calcined at temperatures between 200°C and 1000°C, treated, washed, activated with or used in conjunction with mineral acids such as sulfuric or hydrochloric acid; Other types of solid inorganic acid catalysts, for example but not limited to, based on silicon, silica, aluminum and / or alumina, such as those modified or pillared with aluminum, altered with salts of lithium, sodium, magnesium, iron, etc. and / or exchanged in a medium such as water; natural or synthetic microporous aluminosilicates in proton or cationic form from the zeolite family such as USY, L, mordenite, ferrierite, ZSM-5, beta, etc., with a silica content of 0.1% to 99.9% and / or a pore size of 0.1 ml / g to 5 ml / g and / or a pore size of 100 to 1000 m 2 / g surface area (BET) and calcined at temperatures between 200°C and 1000°C; Mesoporous materials in protonated or cationic form, for example silicoaluminophosphates such as SAPO-11, SAPO-34 or aluminosilicates such as MCM-41, MCM-48 or silicates such as SBA-15, SBA-16, with a silica content of 0.1% to 99.9% and / or a pore size of 0.1 ml / g to 5 ml / g and / or a pore size of 100 to 1000 m 2 / g surface area (BET) and calcined at temperatures between 200°C and 1000°C; supported metals such as Ni, Pt, Au, Fe or Co that are treated, washed, activated with or used in conjunction with mineral acids such as sulfuric acid or hydrochloric acid, modified or pillared with aluminum, hydroiodic acid.

[0036] In embodiments, the catalyst is a Lewis acid based on a metal selected from zinc, boron, aluminum, gallium, indium, titanium, zirconium, tin, vanadium, arsenic, antimony, and bismuth, illustrative examples of which include AlCl, (alkyl)AlCl, (C2H5)2AlCl, and (C2H5)3Al2Cl, BF3, B(C6F5)3, SnCl, TiCl, ZnCl, SnCl, CuCl, combinations thereof, or complexes thereof with Lewis bases. Halogenated metallocenes such as zirconocene dichloride, titanocene dichloride, and hafnocene dichloride, halogenated metallocenes in combination with methylalumoxane, and methylalumoxane can also be used.

[0037] Non-oxidizing Bronsted acids are preferred to prevent or minimize oxidation or oxidative degradation of the cyclic diene and / or comonomer. Non-limiting examples include perfluoroalkanesulfonic acids such as trifluoromethanesulfonic acid, perfluoroalkanoic acids such as trifluoroacetic acid, and alkanesulfonic acids such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, and the like.

[0038] The polymerization reaction generally forms a random copolymer containing polymerized units derived from the cyclic diene and the comonomer. In some cases, the comonomer can act as a chain transfer agent, which can limit the molecular weight of the copolymer.

[0039] The reaction can be carried out by adding the mixture of monomers to the mixture of catalyst and solvent at temperatures of -100°C to +120°C, -50°C to 80°C, or ambient temperatures of 120°C or 50°C to 80°C over a period ranging from 5 minutes to several hours. The reaction period can vary depending on the reactivity of the monomers. Longer reaction periods may be required at lower reaction temperatures. After all the monomers have been added, the resulting reaction mixture can be stirred, if necessary, for an additional period ranging from 5 minutes to several hours until essentially all of the monomers have disappeared, or alternatively, until analysis of the reaction mixture indicates that a copolymer product of sufficient molecular weight has been formed.

[0040] Depending on various factors, such as the structure and reactivity of the monomers, the nature of the reaction solvent, and the temperature, the copolymer produced may be fully soluble in the solvent, somewhat soluble in the solvent, or remain primarily insoluble in the solvent. Generally, it is preferred that the copolymer remain soluble in the solvent. In embodiments, the copolymer has a solubility in the hydrocarbon solvent of 10 to 80 wt. %, 25 to 75 wt. %, 35 to 65 wt. %, 20 to 60 wt. %, or 30 to 50 wt. %, based on the weight of the solvent.

[0041] At the end of the reaction, the copolymer may be isolated, if desired, by quenching the reaction mixture with water, then separating the organic solvent layer and stripping the solvent. Trace organics may be removed from the product under high vacuum.

[0042] Crosslinked Polymers: The copolymers obtained as described above have double bonds resulting from the polymerization of cyclic diene units. These double bonds are reactive to crosslinking agents, such as radical-generating compounds, as curing or curing initiators, allowing for the preparation of crosslinked copolymers. Free radical initiators are particularly desirable. These generate radicals at elevated temperatures or under the trigger of UV or other energy addition. Examples include sulfur-based agents, peroxide-based agents, tellurium, selenium, polysulfide polymers, metal oxides, and diisocyanates. Non-limiting examples of sulfur-based crosslinking agents include S2Cl2, elemental sulfur, and sulfur donor compounds, which liberate sulfur under crosslinking conditions. Some examples of sulfur donor compounds include tetramethylthiuram disulfide, 4,4'-dithiodimorpholine, dipentamethylenethiuram tetrasulfide, and thiocarbamylsulfenamide, dibenzothiazole, N-cyclohexyl-2-benzothiazole, zinc dimethyldithiocarbamate, thiourea, xanthate, and thiophosphate.

[0043] When a curing initiator or crosslinker is used, it is present in an amount of 0.1 to 10 wt. %, or 0.3 to 7 wt. %, or 1 to 5 wt. %, based on the total weight of the copolymer.

[0044] Crosslinking of the copolymer chains can be achieved by reaction with a crosslinking agent at temperatures ranging from ambient to 90°C, or up to 300°C, or <= 280°C, for up to 1 hour, or up to 30 minutes, or at least 5 minutes to obtain a crosslinked copolymer. The crosslink density depends on several factors, such as the amount of crosslinking agent, the temperature, and other physical conditions used. The crosslink density with the S2Cl2 crosslinking agent can vary, for example, from 1 to 10, corresponding to the reaction of 1 to 10 molecules of S2Cl2 per 100 polymerized cyclic diene units.

[0045] In embodiments, after crosslinking (curing) and dissolution in a hydrocarbon solvent forms a substantially gel-free solution, the crosslinked composition being characterized as having a gel content of greater than 50 wt.%, or >70 wt.%, or >90 wt.%, or >85 wt.%, based on the total weight of the copolymer.

[0046] Crosslinked polymers can have good chemical and oxidative stability. Crosslinking also increases the Tg of the resulting crosslinked copolymer, as shown in Figure 1 for a copolymer made with CHD and alpha pinene in an 85:15 weight ratio, respectively. In embodiments, there is a nearly linear increase in Tg with crosslink densities up to 10, and no significant increase in Tg with crosslink densities above 10, such as up to 20.

[0047] The crosslinked copolymer also has enhanced flame retardancy, one of the properties that makes it useful for electronic applications. Flame retardancy can be measured by measuring the time taken from the initiation of ignition of the sample to complete char formation of the sample.

[0048] Copolymer Characteristics: Copolymers are generally resinous materials. They are formed by the cationic polymerization of one or more cyclic dienes via cationic solution polymerization, in which (i) the monomers become linear through both 1,2- and 1,4-insertion modes, and (ii) the linear units undergo disproportionation reactions, simultaneously converting some of the linear cyclohexenyl units to both phenyl and cyclohexane units. The chemical shifts of the phenyl and cyclohexane groups are different from those of the cyclohexenyl groups. The conversion due to cationic polymerization can be indicated by both proton and / or carbon-13 NMR, for example, by the presence of phenyl groups above the NMR sensitivity level of >0.1%, >0.2%, or >0.5% based on the total weight of the copolymer composition.

[0049] Conversion of the linear cyclohexenyl to both phenyl and cyclohexane units results in a substantial increase in the final polymer Tg with conversion rate. In embodiments, at 10% conversion of cyclohexenyl groups, the polymer Tg increases from 100-120°C to 150-160°C. Furthermore, the solubility of the copolymer increases significantly in hydrocarbon solvents such as, for example, toluene and cyclohexane.

[0050] In embodiments, copolymers prepared using the above methods generally have an Mn of 300-5,000 daltons, or 500-3,000 daltons, or <2,000 daltons, or <1,500 daltons, or >500 daltons. In embodiments, the copolymers prepared have an Mz of 2,000-30,000 daltons, or 3,000-25,000 daltons, or <20,000 daltons, or <18,000 daltons, or >2,500 daltons, or >3,000 daltons.

[0051] The copolymers are characterized by being soluble in hydrocarbon solvents, with solubility ranging from 0.1 to 2 g of copolymer per gram of solvent, or >0.2 g / 1 g of solvent, or >1.0 g / 1 g of solvent, or <1.5 g of polymer per gram of solvent, or 0.5 g / 1 g of solvent, or 1 g of polymer per gram of solvent. Soluble copolymers are desirable because they are convenient for further downstream processing and applications. In embodiments, the copolymer solids, upon dissolution in a hydrocarbon solvent, form a substantially gel-free solution, in which <15 wt. %, <10 wt. %, or <5 wt. % of the solids remain insoluble in solvents such as toluene or cyclohexane.

[0052] The copolymer has a glass transition temperature (Tg) of 80-180°C, or 85-170°C, or 90-150°C, or >95°C, or >100°C, or 90-160°C, as measured using a DSC (differential scanning calorimeter) or DMA (dynamic mechanical analyzer).

[0053] After crosslinking, the copolymer exhibits adhesion to metals such as aluminum, copper, etc. In embodiments, the crosslinked copolymer has a strength of 0.2 to 1.5 N / m 2 or 0.5 to 1.25 N / m 2 or >0.50N / m 2 or >0.8N / m 2 or <1.8N / m 2 The copolymers have good adhesion to metal as indicated by a 180°C peel strength of 0.01 to 0.01. The good adhesion to copper makes them useful in electronic applications. The crosslinked polymers of embodiments have a Tg of 120°C-240°C, or 130-180°C, or >140°C, or >150°C.

[0054] The crosslinked copolymers of embodiments have good electrical properties for use in PCB applications, including a low dissipation factor (Df) of <0.01, <0.006, or <0.0055, or in the range of 0.0025 to 0.0045, or 0.0035 to 0.0055, and a low dielectric constant (Dk) of <4.5, or <4.0, or <3.5, or in the range of 2 to 4.0, where Df and Dk are measured according to IPC TM650 2.5.5.13.

[0055] The crosslinked copolymer exhibits good flame retardancy. The flame retardancy of a sample can be evaluated by measuring the time taken for the test sample to ignite and complete char formation, such as a flame retardancy of 60 seconds or less, or <50 seconds, or <40 seconds from the ignition time. In embodiments, the resin has a UL94 rating of V-0 or at least V-1 or at least V-2.

[0056] The crosslinked copolymer further has low moisture absorption, resulting in a material that is less sensitive to environmental conditions both during use and storage. In embodiments, the moisture absorption is 0.05-0.5%, or <0.3%, or <0.2% after immersion in water at 23° C. for 24 hours.

[0057] The crosslinked copolymers further exhibit excellent thermal conductivity, on the order of 0.2-0.7 watts per meter Kelvin (W / mK), or 0.3-0.5 W / mK, or >0.1 W / mK.

[0058] Cross-linked copolymer has high Tg of 140℃~240℃, and >0.35~0.5N / m 2 It is particularly suitable for electronic applications due to its excellent adhesion to metals as indicated by a 180°C peel strength of 0.0025-0.0055%, low dielectric dissipation factor (Df) of 0.0025-0.0055%, flame retardancy of 20 seconds or less from ignition time, and low dielectric constant (Dk) of 2.0-3.0. Crosslinked copolymers produced using sulfur-based crosslinkers exhibit even better flame retardancy than pre-crosslinked copolymers.

[0059] Use of copolymers in electronic applications: Copolymers are useful materials for forming electronic components such as printed circuit boards (PCBs) and flexible printed circuit boards (FPCs). Prepregs used to make PCBs can be made using copolymers. For prepregs, cross-linked copolymers are used in combination with a rubber component.

[0060] The rubber component includes natural rubber and its various raw and reclaim forms, as well as various synthetic rubbers. In embodiments, the rubber component includes any of the unsaturated diene elastomers selected from elastomeric block copolymers, polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymers, isoprene copolymers, and mixtures thereof.

[0061] In an embodiment, the rubber is selected from butyl rubber, halogenated butyl rubber, and EPDM (ethylene propylene diene monomer rubber), and mixtures thereof. In an embodiment, the rubber component is natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber, synthetic polyisoprene rubber, epoxidized natural rubber, polybutadiene rubber, such as high-cis polybutadiene rubber, nitrile hydrogenated butadiene rubber HNBR, hydrogenated SBR, ethylene propylene diene monomer rubber, ethylene propylene rubber, maleic acid modified ethylene propylene rubber, butyl rubber, isobutylene-aromatic vinyl or diene monomer copolymer, brominated NR, chlorinated NR, brominated isobutylene p-methylstyrene copolymer, chloroprene rubber, epichlorohydrin homopolymer rubber, epichlorohydrin-ethylene propylene rubber. oxide or allyl glycidyl ether copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer rubber, chlorosulfonated polyethylene, chlorinated polyethylene, maleic acid modified chlorinated polyethylene, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber, polysulfide rubber, vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, fluorinated silicone rubber, fluorinated phosphagen rubber, styrene elastomer, thermoplastic olefin elastomer, polyester elastomer, urethane elastomer and polyamide elastomer.

[0062] Examples of SBR rubber include emulsion-polymerized styrene-butadiene rubber (unmodified E-SBR), solution-polymerized styrene-butadiene rubber (unmodified S-SBR), and modified SBR obtained by modifying the terminals (modified E-SBR and S-SBR). The rubber component includes components other than SBR and BR, such as natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber (ENR), butyl rubber, acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and styrene-isoprene-butadiene rubber (SIBR), used alone or in combination.

[0063] The rubber component may be coupled, star-branched, branched, and / or functionalized with a coupling agent and / or star-branching agent or functionalizing agent. The branched rubber may be any of branched ("star-branched") butyl rubber, halogenated star-branched butyl rubber, poly(isobutylene-co-p-methylstyrene), brominated butyl rubber, chlorinated butyl rubber, star-branched polyisobutylene rubber, and mixtures thereof.

[0064] When processed into a prepreg composition, the composition may further comprise one or more additives, including but not limited to, multifunctional co-cure additives, diene-based rubbers, halogenated or non-halogenated flame retardants, inorganic or organic fillers or fibers, monovinyl compounds, or other additives known in the art, such as antioxidants, colorants or stabilizers, adhesion promoters, toughening agents, film-forming additives, in an amount ranging from 0.1 to 50 weight percent of the resin composition.

[0065] Compositions containing the copolymers can be laminated onto metal substrates such as copper, and the laminates have several useful properties that make them beneficial for electronic applications, such as little or no blistering or delamination after subjecting the laminate to pressure cooker testing, little or no decomposition during lead-free soldering, chemical resistance to acids, alkalis, and oxidizing agents, little or no water uptake, good resistance to electromigration of the internal laminate, i.e., resistance to CAF (conductive anodic filament) loss, low coefficient of thermal expansion (CTE), and high glass transition temperature for stable performance under use conditions.

[0066] The copolymers are useful as dielectric materials due to their good balance of electrical properties, thermal stability, good thermomechanical and thermal properties for good dimensional stability, and chemical stability, including low dielectric constant, low dielectric loss and leakage current, Df and Dk, high breakdown voltage, high and stable adhesion to metals such as copper under use conditions, little or no effect on the flow of the copolymer resin in prepregs for pressing processes, and sufficient optical quality, such as no clumping of the laminate material.

[0067] When a prepreg is used, the composition further comprises a reinforcing material. The prepreg is used to manufacture a metal foil clad laminate by using a sheet of prepreg and metal foil clad on one or both sides of the prepreg. [Example]

[0068] The following examples are provided to illustrate the present disclosure.

[0069] Example 1: Preparation of 1,3-cyclohexanediene-co-α-pinene copolymer resin (A) A baffled 1 L round-bottom reactor flask was equipped with a stirrer blade, nitrogen inlet, pressure outlet, and temperature probe. 300 grams of toluene solvent (containing 230 ppm water) was added to the reactor. 10.0 grams of AlCl3 was added to the reactor, and the reactor contents were heated to 45°C. A monomer mixture consisting of 150 grams of 1,3-cyclohexadiene and 150 grams of α-pinene was gradually added to the reactor via a membrane pump over 40 minutes. The reactor temperature was maintained at 45°C during the monomer addition by cooling with a water / ice bath. After the monomer addition was completed, the reactor was maintained at 45°C for an additional 15 minutes. A dilute sulfuric acid solution was prepared by adding 4.3 grams of concentrated sulfuric acid to 150 ml of water. The dilute sulfuric acid solution was added to the reactor, and stirring was continued, allowing the temperature to rise to 80°C. After 20 minutes, stirring was stopped, the aqueous and organic layers were allowed to separate, and the aqueous layer was removed. After an additional water wash, 1.1 grams of sodium carbonate dissolved in 150 ml of water was introduced into the reactor. After 20 minutes, the aqueous and organic layers were allowed to separate, the aqueous layer was removed, followed by an additional water wash and the aqueous layer was removed. The solvent was removed from the organic fraction by distillation, and the molten resin was heated in stages to 240°C. Residual solvent, monomer, and light oil were removed by nitrogen stripping for 15 minutes. The molten resin was discharged from the reactor. 1,3-Cyclohexadiene-co-α-pinene Copolymer Resin A had a Mettler Cup and Ball softening point (T) of 148°C. sp ) and was obtained in 79% yield.

[0070] Example 2: Preparation of 1,3-cyclohexadiene-co-α-pinene copolymer resin (B) A baffled 1 L round-bottom reactor flask was equipped with a stirrer blade, nitrogen inlet, pressure outlet, and temperature probe. 374 grams of toluene solvent (containing 230 ppm water) was added to the reactor. 9.1 grams of aluminum trichloride was added to the reactor, and the reactor contents were heated to 45°C. A monomer mixture consisting of 238 grams of 1,3-cyclohexadiene and 42 grams of α-pinene was gradually added to the reactor via a membrane pump over 40 minutes. The reactor temperature was maintained at 45°C during the monomer addition by cooling with a water / ice bath. After the monomer addition was completed, the reactor was maintained at 45°C for an additional 15 minutes. A dilute sulfuric acid solution was prepared by adding 3.7 grams of concentrated sulfuric acid to 150 ml of water. The dilute sulfuric acid solution was added to the reactor, and stirring was continued, allowing the temperature to rise to 80°C. After 20 minutes, stirring was stopped, the aqueous and organic layers were allowed to separate, and the aqueous layer was removed. After further water washing, 1.1 grams of sodium carbonate dissolved in 150 ml of water was introduced into the reactor. After 20 minutes, the aqueous and organic layers were allowed to separate, the aqueous layer was removed, followed by further water washing and the aqueous layer was removed. The solvent was removed from the organic fraction by distillation, and the molten resin was heated in stages to 280°C. Residual solvent, monomer, and light oil were removed by nitrogen stripping for 1 minute. The molten resin was discharged from the reactor. 1,3-cyclohexadiene-co-α-pinene copolymer resin B was obtained with a Mettler Cup and Ball Softening Point (C&B SP) of 172°C and a yield of 92%. Table 1 shows the T values ​​of 1,3-cyclohexadiene-based copolymer resins A and B. sp , Tg, yield, Mn, Mw and Mz are given. Molecular weights are in Daltons (Da).

[0071] [Table 1]

[0072] Example 3: Preparation of 1,3-cyclohexadiene-co-α-pinene copolymer resin (C) A 100 ml round-bottom reactor flask was equipped with a magnetic stir bar, nitrogen inlet, pressure outlet, and temperature probe. 40 grams of toluene solvent (containing 230 ppm water) was then introduced into the reactor, followed by 1.5 grams of AlCl3. A monomer mixture consisting of 1,3-cyclohexadiene (25.5 g) and α-pinene (4.5 g) was slowly added to the reactor through a dropping funnel over 10 minutes. The reactor temperature was maintained at 45°C during the monomer addition by cooling with a water / ice bath. After the monomer addition was complete, the reactor was maintained at 45°C for an additional 10 minutes. A dilute sulfuric acid solution was prepared by adding 1.0 gram of concentrated sulfuric acid to 50 ml of water. The dilute sulfuric acid solution was introduced into the reactor and stirring was continued. After 20 minutes, stirring was stopped, the aqueous and organic layers were allowed to separate, and the aqueous layer was removed. After an additional water wash, the organic layer was discharged from the reactor. Mn, Mw, and Mz were determined by size exclusion chromatography on the resin solution. Tg was determined for the material obtained by removing the solvent by placing 3 grams of the resin solution in a Mettler HG53 Halogen Moisture Balance at 150°C for 15 minutes. Resin C was obtained with a Tg of 107°C. Resins D-H were obtained in a similar manner under the conditions listed in Table 2.

[0073] Example 4: Preparation of 1,3-cyclohexadiene-co-α-pinene and 1,3-cyclohexadiene-co-α-methylstyrene copolymer resins (D to H) The procedure described for making Resin C was used, except that the amounts of 1,3-CHD and comonomer were varied. Table 2 outlines the monomer compositions, reactants, and reaction conditions used to prepare 1,3-cyclohexadiene-co-α-pinene copolymer resins D through H. Table 3 lists the T values ​​for copolymer resins C through H. sp , Tg, Mn, Mw and Mz are outlined.

[0074] [Table 2]

[0075] [Table 3]

[0076] Example 4 The flame retardancy of copolymer resins was tested on copolymer resins obtained by crosslinking the copolymers with S2Cl2. The parameter "T" represents the time from the onset of ignition to the flame extinction time, which corresponds to complete char formation. "RU" indicates the residual unsaturation level in the copolymer resin, expressed as mole % of C=C groups. "RU" and wt% chloride are estimated based on 100% consumption of sulfur monochloride. The results are shown in Table 4.

[0077] [Table 4]

[0078] <Example 5> The crosslinked resin of Example 4 is measured for peel strength, Tg, Dk, and Df. The dissipation factor (Df) and Dk are measured according to IPC TM-650 2.5.5.13. The samples have a Dk (10 GHz) in the range of 3.3 to 3.7, a Df (10 GHz) in the range of 0.0035 to 0.0045, a Tg of 160 to 180°C, and a tensile strength of 0.5 to 1.5 N / m 2 It is expected to have a peel strength of .

[0079] <Examples 6 to 9> In this example, 80 parts by weight of each resin (A, B, C, and D) is mixed with 50 parts by weight of methylbenzene as a solvent to completely dissolve the resin into a resin solution, and then 20 parts by weight of triallyl isocyanurate (TAIC) as a crosslinking agent, 3 parts by weight of dicumyl peroxide DCP as an initiator, 15 parts by weight of ethylene bis(tetrabromophthalimide) as a bromine-containing flame retardant, and 45 parts by weight of silica SO-C2 as a filler are added to the solution. The mixture is stirred and dissolved to form a homogeneous resin composition, i.e., a glue solution.

[0080] Next, the prepared homogeneous glue solution is used to saturate E-glass fiber cloth, which is then heated and dried at 155°C for 3 to 10 minutes to completely volatilize the solvent, thereby obtaining a prepreg. Several prepared prepregs are stacked, and then two 35-μm-thick copper foils are placed on both sides of the stacked prepreg. The assembly of two copper foils and eight prepregs is processed by thermocompression bonding at a temperature of 200°C and a pressure of 3.0 MPa for 90 minutes, thereby obtaining a double-sided copper-clad laminate. The samples are measured for peel strength, Tg, Dk, and Df. The dielectric dissipation factor (Df) and Dk are measured according to IPC TM-650 2.5.5.13. The samples had a Dk (10 GHz) in the range of 3.3 to 3.7, a Df (10 GHz) in the range of 0.0035 to 0.0045, a Tg in the range of 180 to 200°C, and a stiffness of 0.5 to 1.5 N / m 2 It is expected to have a peel strength of .

[0081] Although the terms "comprising" and "including" have been used herein to describe various embodiments, to provide more specific embodiments of the present disclosure, the terms "consisting essentially of" and "consisting of" can also be used in place of "comprising" and "including" and are also disclosed.

Claims

1. 1. A copolymer formed by cationic polymerization of one or more cyclic dienes and comonomers in the presence of a catalyst, comprising: the comonomer is selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof; the one or more cyclic dienes are selected from the group consisting of 1,3-cyclohexadiene (CHD), cyclopentadiene (CPD), 1,3-cycloheptadiene, 4,5,6,7-tetrahydroindene, norbornadiene (NBD), and combinations thereof; the catalyst is selected from the group consisting of Bronsted acids, Lewis acids, and combinations thereof; The copolymer is (i) an Mn of 300 to 5,000 daltons and an Mz of 2,000 to 30,000 daltons; (ii) a solubility in a hydrocarbon solvent selected from the group consisting of toluene and cyclohexane of 0.1 to 2 grams of copolymer per gram of hydrocarbon solvent; (iii) a Tg of 80°C to 180°C, and (iv) at least 0.1% by weight of phenyl groups as determined by proton NMR; A copolymer having the formula:

2. 2. The copolymer of claim 1, wherein the branched styrene comprises any of α-methylstyrene, 1,1-diphenylethylene, or a combination thereof, and the monoterpene is selected from the group consisting of α-pinene, β-pinene, limonene, myrcene, ocimene, α-phellandrene, β-phellandrene, farnesene, camphene, α-terpinene, sabinene, γ-terpinene, 3-carene, and combinations thereof.

3. 10. The copolymer of claim 1 having a molar ratio of one or more cyclic dienes to comonomers ranging from 5:95 to 95:

5.

4. 4. The copolymer according to claim 1, wherein the one or more cyclic dienes comprise a cyclic conjugated diene, and the cyclic conjugated diene is 1,3-cyclohexadiene containing up to 10% by weight of 1,4-cyclohexadiene, based on the total weight of cyclic conjugated dienes.

5. The copolymer according to any one of claims 1 to 3, wherein the one or more cyclic dienes comprise a cyclic conjugated diene, and the cyclic conjugated diene comprises polymerized 1,4-addition units and polymerized 1,2-addition units in a molar ratio of 90:10 to 10:

80.

6. 4. The copolymer of claim 1, wherein the catalyst is a Lewis catalyst, the Lewis acid catalyst comprising a Group 3-8 or Group 12-15 metal and one or more electron-withdrawing groups.

7. The copolymer of any one of claims 1 to 3, wherein the copolymer has a solubility in a hydrocarbon solvent in the range of 10% to 80% by weight relative to the weight of the hydrocarbon solvent.

8. the comonomer is selected from the group consisting of α-methylstyrene, 1,1-diphenylethylene, α-pinene, β-pinene, limonene, myrcene, ocimene, α-phellandrene, β-phellandrene, farnesene, camphene, α-terpinene, sabinene, γ-terpinene, 3-carene, and combinations thereof; the one or more cyclic dienes comprise a cyclic conjugated diene, the cyclic conjugated diene being 1,3-cyclohexadiene containing up to 10 wt % of 1,4-cyclohexadiene based on the total weight of the cyclic conjugated dienes; the copolymer has 5 to 95 mol % of polymerized units derived from 1,3-cyclohexadiene and 95 to 5 mol % of polymerized units derived from the comonomer; the copolymer contains at least 0.1 wt. % phenyl groups as determined by proton NMR; The copolymer according to any one of claims 1 to 3.

9. A crosslinked polymer formed by reaction of the copolymer with a crosslinking agent selected from the group consisting of sulfur-based agents, peroxide-based agents, tellurium, selenium, polysulfide polymers, metal oxides, diisocyanates, and combinations thereof, the copolymer is formed by cationic polymerization of one or more cyclic dienes and a comonomer in the presence of a catalyst, the comonomer being selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof; the one or more cyclic dienes are selected from the group consisting of 1,3-cyclohexadiene (CHD), cyclopentadiene (CPD), 1,3-cycloheptadiene, 4,5,6,7-tetrahydroindene, norbornadiene (NBD), and combinations thereof; the catalyst is selected from the group consisting of Bronsted acids, Lewis acids, and combinations thereof; the copolymer has an Mn of 300 to 5,000 daltons and an Mz of 2,000 to 30,000 daltons and at least 0.1 wt. % phenyl groups as determined by proton NMR; The crosslinked polymer (i) a Tg of 140°C to 240°C; (ii) 0.2-1.5N / m ２ 180° peel strength to copper, (iii) a dissipation factor of 0.0025 to 0.0045 in accordance with IPC TM-650 2.5.5.13; (iv) a dielectric constant Dk of <4.5 according to IPC TM-650 2.5.5.13; and (v) Flame retardancy of <40 seconds, which corresponds to the time required for complete char formation as measured by the ignition time of the sample. A crosslinked polymer having one or more of:

10. A prepreg composition comprising the crosslinked polymer of claim 9, a reinforcing material, and a rubber component.

11. 1. A method of forming a copolymer, comprising: cationic polymerization of one or more cyclic diene-containing monomers and comonomers in the presence of a catalyst in a hydrocarbon solvent selected from the group consisting of toluene and cyclohexane to form said copolymer; and recovering the copolymer; the catalyst is selected from the group consisting of Bronsted acids, Lewis acids, and combinations thereof; the comonomer is selected from the group consisting of monoterpenes, branched styrenes, and combinations thereof; the one or more cyclic dienes are selected from the group consisting of 1,3-cyclohexadiene (CHD), cyclopentadiene (CPD), 1,3-cycloheptadiene, 4,5,6,7-tetrahydroindene, norbornadiene (NBD), and combinations thereof; the copolymer has an Mn of 300 to 5,000 daltons and an Mz of 2000 to 30,000 daltons; The copolymer is (i) a solubility in the hydrocarbon solvent of 0.1 to 2 grams of copolymer per gram of said hydrocarbon solvent; and (ii) Tg of 80°C to 180°C and the copolymer contains at least 0.1 wt. % phenyl groups as determined by proton NMR; method.

12. 12. The method of claim 11, wherein the one or more cyclic dienes comprise a cyclic conjugated diene, the cyclic conjugated diene comprising polymerized 1,4-addition units and polymerized 1,2-addition units in a molar ratio of from 90:10 to 10:

80.

13. The method according to claim 11 or 12, wherein the cationic polymerization is carried out at a reaction temperature of -100°C to 120°C.

14. 13. The method of claim 11 or 12, further comprising crosslinking the recovered polymer with a crosslinking agent to obtain a crosslinked polymer, wherein the crosslinking agent is selected from the group consisting of sulfur-based agents, peroxide-based agents, tellurium, selenium, polysulfide polymers, metal oxides, diisocyanates, and combinations thereof.

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