Epoxy-terminated liquid butadiene polymer, preparation method and application thereof, composition and application thereof, and polymer coating

Abstract

The invention relates to the field of polymers, and discloses an epoxy-terminated liquid butadiene polymer, a preparation method and application thereof, a composition and application thereof, and a polymer coating. The functionality degree of the epoxy-terminated liquid butadiene polymer is 1.9 to 2; on the basis of the total weight of the epoxy-terminated liquid butadiene polymer, the total content of the 1, 2-structural unit and the cyclized 1, 2-structural unit is 60-74.5 wt%, and the content of the 1, 4-structural unit is 25.5-40 wt%; based on the total weight of the 1, 2-structural unit and the cyclized 1, 2-structural unit in the epoxy-terminated liquid polybutadiene polymer, the content of the cyclized 1, 2-structural unit is 15-35 wt%. The epoxy-terminated liquid butadiene polymer has good performance, and a polymer coating formed by the polymer has a lower thermal expansion coefficient under the condition of keeping high peel strength with a metal matrix.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology, and relates to an epoxy-terminated liquid butadiene polymer, its preparation method and application, as well as compositions and applications and polymer coatings. Background Technology

[0002] Liquid butadiene polymer, as an important polymer material, has shown unique advantages in the field of high-frequency electronic circuits, such as extremely low dielectric constant and dielectric loss, which make it an ideal choice for high-frequency signal transmission.

[0003] High-vinyl liquid butadiene polymers refer to liquid butadiene polymers with a 1,2-structure content >65%. Because most of the double bonds are located on the molecular side chains, they exhibit high activity in photo- (or thermal) crosslinking reactions and are easy to cure by light (or heat). However, the coatings formed after curing exhibit poor heat resistance and their adhesion to metal surfaces is not ideal. To meet the demands of the rapidly developing high-frequency communication technology, improving the heat resistance and metal adhesion of liquid butadiene polymers has become particularly important. This will not only expand their application range in high-frequency electronic circuits but also improve the overall performance and reliability of products. Therefore, researchers are committed to continuously improving the performance of liquid butadiene polymers through material modification and new synthesis methods to meet the growing market demand.

[0004] CN202011175471.8 discloses a liquid butadiene polymer with a number average molecular weight of 2500-5500, a molecular weight distribution of 1-1.2, and a vinyl content of 85-95%. This liquid butadiene polymer has low dielectric constant, dielectric loss, and film-forming properties, but its heat resistance and adhesion to metals are unsatisfactory. CN114106228A discloses a method for preparing a liquid butadiene polymer and its product, which can meet the crosslinking and curing activity requirements of the high-end electronics industry, but it also cannot solve the problems of heat resistance and adhesion to metals.

[0005] Therefore, improving the heat resistance and adhesion of liquid butadiene polymers to metals is of great significance for meeting the rapid development of high-frequency communication technology and is the key to promoting the continuous progress of high-frequency communication technology. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical problems of high thermal expansion coefficient and unsatisfactory adhesion to metals in liquid butadiene polymers prepared by existing technologies. This invention provides an epoxy-terminated liquid butadiene polymer, its preparation method and applications, as well as compositions, applications, and polymer coatings. The epoxy-terminated liquid butadiene polymer has a high content of 1,2-structural units and a cyclized structure, while also possessing epoxy-terminated ends and high functionality. The polymer coating formed from this epoxy-terminated liquid butadiene polymer improves the adhesion between the liquid butadiene polymer and the metal substrate, and simultaneously exhibits improved thermal expansion properties, thus completing this invention.

[0007] To achieve the above objectives, a first aspect of the present invention provides a terminal epoxy-based liquid butadiene polymer, wherein the functionality of the terminal epoxy-based liquid butadiene polymer is 1.9-2; based on the total weight of the terminal epoxy-based liquid butadiene polymer, the content of 1,2-structural units is 60-74.5% by weight, and the content of 1,4-structural units is 25.5-40% by weight; based on the total weight of 1,2-structural units in the terminal epoxy-based liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

[0008] A second aspect of the present invention provides a method for preparing an epoxy-terminated liquid butadiene polymer, the method comprising:

[0009] (1) In the presence of a solvent and a structure modifier, 1,3-butadiene monomer is contacted with an initiator to carry out an anionic solution polymerization reaction to obtain a polymerization reaction solution containing butadiene polymer; wherein, the contact is carried out at a temperature of 50-100°C, the structure modifier is an alkali metal alkoxide, the initiator is an organic bislithium initiator, the molar ratio of the structure modifier to the initiator is 0.1-0.8:1, and the solvent contains an alicyclic solvent;

[0010] (2) Add an epoxy end-capping agent to the polymerization reaction solution obtained in step (1) to carry out the end-capping reaction. After the end-capping reaction is complete, add a halogenated epoxy compound to carry out the reaction to obtain a terminal epoxy liquid butadiene polymer.

[0011] A third aspect of the present invention provides a terminal epoxy group liquid butadiene polymer prepared by the above method.

[0012] A fourth aspect of the present invention provides a composition comprising a terminal epoxy-based liquid butadiene polymer and at least one additive, wherein the terminal epoxy-based liquid butadiene polymer is the terminal epoxy-based liquid butadiene polymer described in the first and third aspects above.

[0013] The fifth aspect of the present invention provides a polymer coating comprising the terminal epoxy liquid butadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above.

[0014] The sixth aspect of the present invention provides the use of the terminal epoxy liquid butadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above, as a crosslinking agent, adhesive, or electrical insulating material.

[0015] Through the above technical solution, the terminal epoxy liquid butadiene polymer provided by the present invention has good performance. The coating formed by the terminal epoxy liquid polybutadiene polymer not only has a high weight loss temperature Td5, but also has high peel strength to metal substrates, and at the same time improves thermal expansion performance, showing broad application prospects in the field of communication technology; and the preparation process is simple and efficient, which is conducive to actual production. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] In this invention, the term "liquid butadiene polymer" refers to a butadiene polymer that is fluid at 25°C and 1 standard atmosphere.

[0018] In this invention, the term "1,2-structural unit" refers to the structural unit formed by the 1,2-polymerization of 1,3-butadiene, and the content of 1,2-structural units can also be referred to as the vinyl content.

[0019] In this invention, the term "1,4-structural unit" refers to the structural unit formed by the 1,4-polymerization of 1,3-butadiene.

[0020] In this invention, the term "cyclized 1,2-structural unit" refers to the formation of a five-membered ring from the vinyl bonds in two adjacent 1,2-structural units, as shown in the following structure:

[0021]

[0022] In this invention, the contents of 1,2-structural units, 1,4-structural units, and cyclized 1,2-structural units in the polymer were determined by nuclear magnetic resonance spectroscopy.

[0023] In this invention, the specific testing method of the nuclear magnetic resonance spectroscopy is as follows: a Bruker AVANCE400 superconducting nuclear magnetic resonance spectrometer is used. 1 H-NMR test, 1 The resonance frequency of the H nucleus was 300.13 MHz, the spectral width was 2747.253 Hz, the pulse width was 5.0 μs, the data point was 16 K, the sample tube diameter was 5 mm, the solvent was deuterated chloroform (CDCl3), the sample concentration was 15% (mg / mL), the test temperature was room temperature (25℃), the number of scans was 16, and the calibration was performed with a tetramethylsilane chemical shift of 0 ppm.

[0024] In this invention, molecular weight and molecular weight distribution index (Mw / Mn) are determined by gel permeation chromatography. The specific test method is as follows: an HLC-8320 gel permeation chromatograph from Tosoh Corporation of Japan is used, with a TSKgel SuperMultipore HZ-N column, a TSKgel SuperMultipore HZ standard column, and chromatographically pure tetrahydrofuran (THF) as the solvent. Narrow distribution polystyrene is used as the standard sample. The polymer sample is prepared into a tetrahydrofuran solution with a concentration of 1 mg / mL. The injection volume is 10.00 μL, the flow rate is 0.35 mL / min, and the test temperature is 40.0℃.

[0025] In this invention, the weight loss temperature Td5 (the temperature at which the thermal weight loss reaches 5%) is measured using a TA-2980DSC differential scanning calorimeter. The specific procedure is as follows: the temperature is increased from 25°C to 600°C at a rate of 10°C / min under a nitrogen atmosphere.

[0026] In this invention, the linear coefficient of thermal expansion is determined by thermomechanical analysis (TMA) according to the method specified in GB / T 36800.2-2018.

[0027] In this invention, the peel strength between the polymer coating and the metal substrate (copper foil) is tested using the method specified in IPC-TM-650.

[0028] The first aspect of the present invention provides a terminal epoxy-based liquid butadiene polymer, wherein the functionality of the terminal epoxy-based liquid butadiene polymer is 1.9-2; based on the total weight of the terminal epoxy-based liquid butadiene polymer, the content of 1,2-structural units is 60-74.5% by weight, and the content of 1,4-structural units is 25.5-40% by weight; based on the total weight of 1,2-structural units in the terminal epoxy-based liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

[0029] In some embodiments of the present invention, it is preferably stated that the functionality of the terminal epoxy group liquid butadiene polymer is 1.9-2, for example, it can be 1.9, 1.91, 1.92, 1.93, 1.94, 1.95, 1.96, 1.97, 1.98, 1.99, 2, or any value within the range of any two values, preferably 1.9-1.96. The terminal epoxy group liquid butadiene polymer of the present invention has high functionality, which is beneficial for improving the adhesion between the polymer coating formed under the same crosslinking conditions and the metal matrix.

[0030] In some embodiments of the present invention, preferably, the content of 1,2-structural units is 60-74.5% by weight, based on the total weight of the terminal epoxy-based liquid butadiene polymer. For example, it can be 60% by weight, 61% by weight, 62% by weight, 63% by weight, 64% by weight, 65% by weight, 66% by weight, 67% by weight, 68% by weight, 69% by weight, 70% by weight, 71% by weight, 72% by weight, 73% by weight, 74% by weight, 74.5% by weight, or any value within a range of any two of these values. More preferably, the content of 1,2-structural units is 65-74.5% by weight, based on the total weight of the terminal epoxy-based liquid butadiene polymer.

[0031] In some embodiments of the present invention, preferably, the content of the 1,4-structural units is 25.5-40% by weight, based on the total weight of the terminal epoxy-based liquid butadiene polymer. For example, it can be 25.5% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight, 36% by weight, 37% by weight, 38% by weight, 39% by weight, 40% by weight, or any value within a range of any two values. More preferably, the content of the 1,4-structural units is 25.5-35% by weight, based on the total weight of the terminal epoxy-based liquid butadiene polymer. In the present invention, a content of less than 25.5% by weight affects the content of cyclized structural units in the polymer; a content of more than 35% by weight reduces the number of double bonds that can participate in curing crosslinking, resulting in a lower crosslinking density in the polymer coating made from the polymer.

[0032] In some embodiments of the present invention, preferably, the content of cyclized 1,2-structural units is 15-35% by weight, based on the weight of the 1,2-structural units in the terminal epoxy-based liquid polybutadiene polymer. For example, it can be any value within the range of any two of these values: 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, 20% by weight, 21% by weight, 22% by weight, 23% by weight, 24% by weight, 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight. More preferably, the content of cyclized 1,2-structural units is 20-30% by weight, based on the weight of the 1,2-structural units in the terminal epoxy-based liquid polybutadiene polymer. In this invention, when the weight of the cyclized 1,2-structural units is controlled within the above-mentioned range, the overall performance of the polymer coating after curing is better; when the content of the cyclized 1,2-structural units is less than 15% by weight, the improvement in the coefficient of thermal expansion of the polymer coating after curing is not significant; when the content of the cyclized 1,2-structural units is greater than 35% by weight, it is not conducive to increasing the total 1,2-structure content of the polymer, and the crosslinking density of the polymer coating made from this polymer is reduced.

[0033] In some embodiments of the present invention, preferably, the number-average molecular weight of the terminal epoxy group liquid butadiene polymer is 1000-5000 g / mol, more preferably 1500-4500 g / mol, and even more preferably 1800-4300 g / mol.

[0034] In this invention, the terminal epoxy-based liquid butadiene polymer has a molecular weight suitable for molding and a narrow molecular weight distribution. In some embodiments of this invention, preferably, the molecular weight distribution index of the terminal epoxy-based liquid butadiene polymer is 1-1.2, more preferably 1-1.15.

[0035] In some embodiments of the present invention, preferably, the linear coefficient of thermal expansion of the terminal epoxy-terminated liquid butadiene polymer after curing is 50 × 10⁻⁶. -6 m / m / ℃-80×10 -6 m / m / ℃, preferably 50×10 -6 m / m / ℃-70×10 -6 m / m / ℃.

[0036] In some embodiments of the present invention, preferably, the peel strength between the coating formed by the terminal epoxy liquid butadiene polymer and the metal substrate (e.g., copper foil) is 1-1.3 N / mm, more preferably 1.04-1.25 N / mm.

[0037] In some embodiments of the present invention, preferably, the weight loss temperature Td5 of the terminal epoxy group liquid butadiene polymer is 380°C to 410°C, preferably 395°C to 405°C. In the present invention, the weight loss temperature Td5 refers to the temperature when the thermal weight loss reaches 5%.

[0038] The second aspect of the present invention provides a method for preparing a terminal epoxy group liquid butadiene polymer, the method comprising:

[0039] (1) In the presence of a solvent and a structure regulator, contacting 1,3-butadiene monomer with an initiator to carry out an anionic solution polymerization reaction to obtain a polymerization reaction solution containing a butadiene polymer; wherein, the contacting is carried out at a temperature of 50 - 100°C, the structure regulator is an alkali metal alcoholate, the initiator is an organic dilithium initiator, the molar ratio of the structure regulator to the initiator is 0.1 - 0.8:1, and the solvent contains a heterocyclic solvent;

[0040] (2) Adding an epoxide terminator to the polymerization reaction solution obtained in step (1) for a termination reaction, and after the termination reaction is complete, adding a halogenated epoxide for reaction to obtain a terminal epoxy group liquid butadiene polymer.

[0041] In the present invention, the contents of 1,4-structure units, 1,2-structure units and cyclized 1,2-structure units in the terminal epoxy group liquid butadiene polymer are determined by step (1), and the termination reaction and subsequent reactions do not affect the contents of 1,4-structure units, 1,2-structure units and cyclized 1,2-structure units in the liquid butene polymer.

[0042] In some embodiments of the present invention, preferably, the structure regulator is one or more selected from the compounds shown in formula I,

[0043] R₁ - O——M (formula I)

[0044] In formula I, R₁ is a heteroatom-substituted or unsubstituted C₁ - C 20 alkyl group, or a C₄ - C 20 cycloalkyl group;

[0045] M₁ is an alkali metal atom, for example, it can be Li, Na or K, preferably Na.

[0046] In formula I, the unsubstituted C₁ - C 20 alkyl group includes a C₁ - C s 20 linear alkyl group and a C₃ - C 20Branched alkyl groups, specific examples of which may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl and its isomers, n-hexyl and its isomers, n-heptyl and its isomers, n-octyl and its isomers, n-nonyl and its isomers, n-decyl and its isomers, undecyl and its isomers, dodecyl and its isomers, tridecyl and its isomers, tetradecyl and its isomers, pentadecyl and its isomers, hexadecyl and its isomers, heptadecanyl and its isomers, octadecyl and its isomers, nonadecanyl and its isomers, and eicosyl and its isomers.

[0047] In Formula I, the heteroatom-substituted C1-C 20 In the alkyl group, heteroatoms exist on the alkyl carbon chain in the form of substituents, wherein the substituents are preferably cycloalkyl groups containing heteroatoms, and specific examples of heteroatoms may include, but are not limited to, oxygen atoms, sulfur atoms, or nitrogen atoms. In a preferred embodiment, the heteroatom substituted is an oxygen atom, and the substituent substituted is an oxygen-containing cycloalkyl group, such as: ethylene oxide substituent, propylene oxide substituent, tetrahydrofuran substituent, or pentane oxide substituent.

[0048] In Equation I, C4-C 20 The cycloalkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-n-propylcyclohexyl, 4-n-butylcyclohexyl, or 2-isopropyl-5-methylcyclohexyl.

[0049] In some embodiments of the present invention, preferably, the structure modifier is selected from at least one of sodium tetrahydrofurfuryl alcohol, sodium ethoxylate, sodium tert-pentoxylate, sodium tert-butoxylate, sodium n-hexanoate, and sodium menthol.

[0050] In this invention, the amount of the structure modifier can be adjusted according to the amount of monomer and / or polymerization initiator. In some embodiments of this invention, preferably, the molar ratio of the structure modifier to the initiator is 0.1-0.8:1, for example, it can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, and any value within any range of any two values, more preferably 0.2-0.6:1.

[0051] In some embodiments of the present invention, preferably, the initiator is an organic bislithium initiator. The type of bislithium initiator is not particularly limited and can be any existing compound containing two lithium atoms and capable of bidirectionally initiating anionic polymerization reactions. For example, the organic bislithium initiator can be selected from at least one of alkane-based bislithium, naphthalene-based bislithium, and diene-based bislithium.

[0052] In this invention, preferably, the alkane-based double lithium has the general formula LiRLi, where R is C4-C. 10 Alkyl groups, including but not limited to at least one of Li(CH2)4Li, Li(CH2)6Li, and Li(CH2)8Li.

[0053] In this invention, preferably, the naphthalene-based bislithium is naphthalene lithium and / or α-methylnaphthalene lithium.

[0054] In this invention, preferably, the diene-based bislithium is selected from at least one of butadiene-based bislithium, 1,1'-(1,3-phenylene)-bis[3-methyl-1-(4-tolyl)pentyl]bislithium and 1,1'-(1,4-phenylene)-bis[3-methyl-1-(4-tolyl)pentyl]bislithium.

[0055] In this invention, the amount of initiator can be selected based on the expected molecular weight of the terminal epoxy group liquid butadiene polymer. Preferably, the amount of initiator is such that the number average molecular weight of the prepared terminal epoxy group liquid butadiene polymer is 1000-5000 g / mol, more preferably 1500-4500 g / mol, and even more preferably 1800-4300 g / mol. The method for determining the specific amount of initiator based on the expected polymer molecular weight is well known to those skilled in the art and will not be described in detail herein.

[0056] In some embodiments of the present invention, preferably, the solvent contains an alicyclic solvent. The term "alicyclic" refers to a cycloalkanes in which at least one carbon atom in the ring is replaced by a heteroatom. The heteroatom in the alicyclic ring can be an oxygen atom, a nitrogen atom, or a sulfur atom, preferably an oxygen atom.

[0057] In this invention, the solvent can be used alone or in combination. The type of solvent has a wide range of choices. Preferably, the solvent is an oxacycloalkane. The oxacycloalkane of this invention can be selected from at least one of tetrahydrofuran, cyclopentane oxide, cyclohexane oxide, and 1,4-dioxane; preferably, the solvent is tetrahydrofuran.

[0058] In some embodiments of the present invention, preferably, the 1,3-butadiene monomer is contacted with an initiator in the presence of a solvent and a structure modifier to carry out an anionic solution polymerization reaction. Preferably, the 1,3-butadiene is contacted with the structure modifier and the initiator at a temperature of 50°C to 100°C to carry out the anionic polymerization reaction. More preferably, the 1,3-butadiene is contacted with the structure modifier and the initiator at a temperature of 60°C to 90°C. Even more preferably, the 1,3-butadiene is contacted with the structure modifier and the initiator at a temperature of 65°C to 85°C.

[0059] In this invention, the amount of 1,3-butadiene monomer used has a wide range of selection. Preferably, based on the total weight of solvent and 1,3-butadiene monomer, the content of 1,3-butadiene monomer is 1-10% by weight, preferably 1.5-10% by weight. In this invention, monomer content refers to the total weight percentage of 1,3-butadiene monomer determined based on the total weight of solvent and 1,3-butadiene monomer after the polymerization reaction.

[0060] In this invention, the pressure of the anionic solution polymerization reaction is not particularly limited. For example, the anionic polymerization reaction can be carried out at a pressure of 0.005-1.5 MPa, preferably at 0.1-1 MPa, and more preferably at 0.2-0.6 MPa. In this invention, all pressures refer to gauge pressure. The polymerization reaction time can be selected according to the final monomer concentration and polymerization temperature, generally 10-12 minutes after the monomer feeding is completed, preferably 30-80 minutes.

[0061] In this invention, the anionic solution polymerization reaction is carried out in an atmosphere formed by an inert gas. The inert gas refers to a gas that does not chemically interact with the reactants, reaction products, and solvent under polymerization conditions, such as nitrogen and / or group zero element gases (e.g., argon).

[0062] In this invention, preferably, after the anionic polymerization reaction is completed, an epoxy compound end-capping agent is added to carry out the end-capping reaction.

[0063] In this invention, the type of epoxy compound is not particularly limited. Preferably, the epoxy compound is at least one selected from ethylene oxide, propylene oxide, and butane oxide, and more preferably ethylene oxide and / or propylene oxide.

[0064] In this invention, the amount of epoxy compound used is not particularly limited, as long as it is sufficient to completely end-cap the polymer. Excessive epoxy compound will interfere with subsequent reactions. Preferably, the molar ratio of the epoxy compound to the initiator is 2-3:1.

[0065] In this invention, the conditions for the end-capping reaction are not particularly limited. Preferably, the temperature of the end-capping reaction is 10-80°C, more preferably 30-70°C; and the time of the end-capping reaction is 5-90 min, more preferably 20-60 min.

[0066] In this invention, preferably, after the end-capping reaction is complete, a haloepoxide compound is added for further reaction to obtain a terminal epoxy-based liquid butadiene polymer. In this invention, an epoxy group is introduced at the end of the polymer chain through the reaction. Specifically, the end-capping reaction converts highly reactive polybutadiene-based lithium into less reactive polybutadiene-based lithium oxide, which then undergoes a substitution reaction with the halogen atoms on the added haloepoxide compound to form a terminal epoxy-based liquid butadiene polymer.

[0067] In this invention, the type of chloroepoxide compound is not particularly limited. Preferably, the halogenated epoxide compound is a chloroepoxide compound. More preferably, the halogenated epoxide compound is selected from epichlorohydrin and / or methyl epichlorohydrin.

[0068] In this invention, the amount of the chlorinated epoxy compound can be selected within a wide range. Preferably, the molar ratio of the chlorinated epoxy compound to the initiator is 2-4:1, more preferably 2.5-3.5:1.

[0069] In this invention, the conditions for the reaction of adding the haloepoxide compound are not particularly limited. Preferably, the reaction temperature for adding the haloepoxide compound is 10-80°C, more preferably 20-70°C; the reaction time is 5-90 min, more preferably 20-60 min.

[0070] In this invention, preferably, the preparation method further includes: after the reaction with the addition of the halogenated epoxy compound is completed, a terminator is added, followed by washing, precipitation, and drying to obtain a terminal epoxy-based liquid butadiene polymer. More preferably, the preparation method further includes: mixing the polymerization reaction solution obtained after adding the terminator with a washing liquid, precipitating and separating the layers, separating the oil phase from the polymerization reaction solution, removing at least some volatile components, and obtaining the terminal epoxy-based liquid butadiene polymer.

[0071] In this invention, there are no particular limitations on the type and amount of the terminating agent. Conventional terminating agents in the art can be used and added in the conventional amounts in the art.

[0072] In this invention, the washing method and conditions can be those known to those skilled in the art, as long as they can further remove at least some of the metal ions from the polymerization reaction solution. Preferably, the washing solution is water or an aqueous solution containing acid.

[0073] In this invention, the precipitation method and conditions can be any precipitation method and conditions known to those skilled in the art, as long as they can cause the washed polymerization reaction solution to separate into an aqueous phase and an oil phase.

[0074] In this invention, the drying method and conditions can be those known to those skilled in the art, and will not be described in detail here.

[0075] In this invention, the various reagents used in the preparation method are preferably purified using conventional methods in the art before use to remove impurities (especially moisture). Methods for purifying reagents are well known in the art and will not be described further herein.

[0076] In this invention, the anionic solution polymerization reaction can be carried out by either batch polymerization or continuous polymerization, without any particular limitation.

[0077] A third aspect of the present invention provides a terminal epoxy group liquid butadiene polymer prepared by the above method.

[0078] The epoxy-terminated liquid butadiene polymer prepared by the method described in the second aspect of this invention not only has a high content of 1,2-structural units, but also some of these 1,2-structural units form a cyclic structure, endowing the polymer coating formed by the liquid butadiene polymer with excellent crosslinking density and maintaining good stability even under relatively harsh conditions. Furthermore, the epoxy-terminated liquid butadiene polymer contains epoxy groups at both ends, increasing the adhesion between the liquid butadiene polymer and the metal, thereby improving the adhesion between the crosslinked liquid butadiene polymer and the metal. The polymer coating formed by the epoxy-terminated liquid butadiene polymer prepared by the method described in the second aspect of this invention exhibits superior thermal expansion properties while maintaining high peel strength.

[0079] A fourth aspect of the present invention provides a composition comprising a terminal epoxy-based liquid butadiene polymer and at least one additive, wherein the terminal epoxy-based liquid butadiene polymer is the terminal epoxy-based liquid butadiene polymer described in the first and third aspects above.

[0080] In this invention, the additive can be a substance that imparts new properties to the composition and / or improves the existing properties of the composition. As a preferred example, the additive contains an antioxidant. The antioxidant can be of conventional selection, for example, the antioxidant can be a phenolic and / or amine antioxidant. Specifically, the antioxidant can be one or more of 4,6-dioctylthiomethyl o-cresol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (i.e., antioxidant 264), tris(2,4-di-tert-butylphenyl) phosphite (i.e., antioxidant 168), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (i.e., antioxidant 1076), 2,6-di-tert-butyl-p-cresol, tert-butylcatechol, and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). The antioxidant content can be 0.005-2 parts by weight, preferably 0.01-1 parts by weight, relative to 100 parts by weight of liquid butadiene polymer.

[0081] A fifth aspect of the present invention provides a polymer coating comprising the terminal epoxy liquid butadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above.

[0082] In this invention, the polymer coating not only has high adhesion and bonding to the metal substrate, but also has a reduced coefficient of thermal expansion, exhibiting improved thermal expansion performance.

[0083] The sixth aspect of the present invention provides the use of the epoxy-terminated liquid butadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above, as a crosslinking agent, adhesive, or electrical insulating material.

[0084] The present invention will be described in detail below through embodiments.

[0085] Unless otherwise specified, room temperature and room temperature are both expressed as 25±3℃.

[0086] In the following examples and comparative examples, the microstructure of the polymer was determined using a Bruker AVANCE 400 superconducting nuclear magnetic resonance spectrometer. 1 H-NMR) determination, 1 The resonance frequency of the H nucleus was 300.13 MHz, the spectral width was 2747.253 Hz, the pulse width was 5.0 μs, the data point was 16 K, the sample tube diameter was 5 mm, the solvent was deuterated chloroform (CDCl3), the sample concentration was 15% (W / V), the test temperature was room temperature, the number of scans was 16, and the calibration was performed with a tetramethylsilane chemical shift of 0 ppm.

[0087] In the following examples and comparative examples, the molecular weight and molecular weight distribution index of the polymers were determined by gel permeation chromatography. The gel permeation chromatography was performed using an HLC-8320 gel permeation chromatograph from Tosoh Corporation, Japan. The chromatographic column was TSKgel SuperMultipore HZ-N, the standard column was TSKgel SuperMultipore HZ, the solvent was chromatographically pure tetrahydrofuran (THF), and narrow distribution polystyrene was used as the standard sample. The polymer sample was prepared into a tetrahydrofuran solution with a mass concentration of 1 mg / mL. The injection volume was 10.00 μL, the flow rate was 0.35 mL / min, and the test temperature was 40.0 °C.

[0088] In the following examples and comparative examples, the functionality of the polymers was determined according to the national standard GB / T 1677-2008, and the epoxy value was determined by the hydrochloric acid-acetone method. Functionality = epoxy value (mmol / g) * Mn (g / mol) / 1000.

[0089] In the following examples and comparative examples, the weight loss temperature Td5 (the temperature at which the thermal weight loss reaches 5%) of the cured polymer was determined using a TA-2980DSC differential scanning calorimeter. The specific procedure was as follows: the temperature was increased from 25°C to 600°C at a rate of 10°C / min under a nitrogen atmosphere.

[0090] In the following examples and comparative examples, the linear thermal expansion coefficient was determined by thermomechanical analysis (TMA) according to the method specified in GB / T 36800.2-2018.

[0091] In the following examples and comparative examples, the peel strength between the polymer coating and the copper foil was tested using the method specified in IPC-TM-650 2.4.08C.

[0092] The following examples and comparative examples involve the following chemical reagents:

[0093] Antioxidant 264, Antioxidant 168 and Antioxidant 1076 were purchased from Sinopharm Reagent Company;

[0094] Butadiene-based bislithium: self-made, chemical formula C4H6Li2;

[0095] 1,3-Butadiene: Polymer grade, purchased from Yanshan Petrochemical;

[0096] Sodium tert-pentoxygenate (STA): purchased from Bailingwei Reagent Company, 1.4 mol / L tetrahydrofuran solution;

[0097] Sodium tetrahydrofurfuryl alcohol (THFOA): purchased from Inokai Reagent Company, 1.0 mol / L tetrahydrofuran solution;

[0098] Sodium menthol (SMT): purchased from Inokai Reagents, 1.0 mol / L tetrahydrofuran solution;

[0099] Ethylene oxide (EO): Purchased from Inokai Reagents, 98% pure. After distillation in the presence of calcium hydride, it was prepared into a 20 wt% tetrahydrofuran solution for use.

[0100] Propylene oxide: purchased from Inokai Reagents, 99% purity, distilled in the presence of calcium hydride and prepared as a 20 wt% tetrahydrofuran solution for use.

[0101] Epichlorohydrin: Purchased from Inokai Reagent Company, analytical grade, dried with molecular sieve, and then prepared into a 20 wt% tetrahydrofuran solution for use.

[0102] Preparation Example

[0103] The preparation process of the butadiene-based bislithium initiator is as follows:

[0104] (1) Vacuuming, high-temperature baking and nitrogen replacement of 250mL reaction bottle 1 and absorption bottle were repeated 5 times to remove impurities such as water and oxygen in the system. Then cyclohexane and butadiene were added to the absorption bottle to obtain a butadiene cyclohexane solution with a concentration of 2.8mol / L.

[0105] (2) Vacuuming, high-temperature baking, and nitrogen replacement of 250mL reaction flask 2 were repeated 5 times to remove impurities such as water and oxygen in the system. Under nitrogen protection, lithium was cut into small pieces. Naphthalene, lithium and THF were added to reaction flask 2 in sequence. The molar ratio of naphthalene, lithium and THF was 1:1.2:5. The reaction was carried out at 25℃ for 2 hours under electromagnetic stirring to obtain naphthalene-lithium solution. The solution was then placed in a freezer for refrigeration.

[0106] (3) Add 36 mL of the naphthalene lithium solution described in step (2) to reaction flask 1, and add 95 mL of the butadiene cyclohexane solution described in step (1) to reaction flask 1. React at 35 °C for 1 h under electromagnetic stirring to obtain butadiene-based bislithium initiator (C4H6Li2).

[0107] Example 1

[0108] This embodiment illustrates the epoxy-terminated liquid butadiene polymer and its preparation method of the present invention.

[0109] (1) Under nitrogen protection, tetrahydrofuran (THF), structure modifier, and 1,3-butadiene (the types and amounts are shown in Table 1, and the amounts listed in Table 1 are all measured as pure compounds) are added to a 5L reactor. The temperature inside the reactor is controlled to the polymerization reaction temperature listed in Table 1. The designed amount of butadiene-based bislithium initiator described in the preparation example is added to the reactor (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured as pure compounds). Anionic solution polymerization reaction is carried out at the temperature and pressure listed in Table 1 to obtain a polymerization reaction mixture of liquid butadiene polymer.

[0110] (2) Add an epoxy compound solution (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured by pure compounds) to the polymerization reaction mixture of the liquid butadiene polymer obtained in step (1). Carry out the end-capping reaction at the end-capping temperature listed in Table 1. After the reaction is completed, add a tetrahydrofuran solution of epichlorohydrin (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured by pure compounds). Carry out the reaction at the temperature listed in Table 1. Then add an ethanol solution to terminate the reaction. After washing with water and precipitation, add an antioxidant (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured by pure compounds) to obtain a liquid polybutadiene polymer PB1 containing terminal epoxy groups. The structural property parameters of the liquid butadiene polymer containing terminal epoxy groups are listed in Table 2.

[0111] Example 2-10

[0112] Examples 2-10 illustrate the terminal epoxy group liquid butadiene polymer and its preparation method of the present invention.

[0113] Examples 2-10 were prepared using the same method as in Example 1 to prepare terminal epoxy group liquid butadiene polymers, except that steps (1) and (2) were carried out under the conditions shown in Table 1 to obtain terminal epoxy group liquid butadiene polymers PB2-PB10, respectively. The structural property parameters of the terminal epoxy group liquid butadiene polymers are listed in Table 2.

[0114] Comparative Example 1

[0115] The epoxy-terminated liquid butadiene polymer was prepared using the same method as in Example 1, except that the polymerization temperature in step (1) was 20°C, resulting in epoxy-terminated liquid butadiene polymer DPB1. The structural properties of the epoxy-terminated liquid butadiene polymer are listed in Table 3.

[0116] Comparative Example 2

[0117] The terminal epoxy group liquid butadiene polymer was prepared using the same method as in Example 1, except that no structure modifier was added in step (1) to obtain the terminal epoxy group liquid butadiene polymer DPB2. The structural property parameters of the terminal epoxy group liquid butadiene polymer are listed in Table 3.

[0118] Comparative Example 3

[0119] The terminal epoxy group liquid butadiene polymer was prepared using the same method as in Example 1, except that in step (1), the STA structure modifier was replaced by an equal amount of sodium dodecylbenzenesulfonate to obtain the terminal epoxy group liquid butadiene polymer DPB3. The structural property parameters of the terminal epoxy group liquid butadiene polymer are listed in Table 3.

[0120] Comparative Example 4

[0121] The terminal epoxy liquid butadiene polymer was prepared using the same method as in Example 1, except that in step (1), cyclohexane was used in an equal amount to replace tetrahydrofuran to obtain the terminal epoxy liquid butadiene polymer DPB4. The structural property parameters of the terminal epoxy liquid butadiene polymer are listed in Table 3.

[0122] Comparative Example 5

[0123] The terminal epoxy liquid butadiene polymer was prepared using the same method as in Example 1. The difference was that in step (1), the bislithium initiator was replaced with an equal amount of n-butyllithium to obtain the terminal epoxy liquid butadiene polymer DPB5. The structural property parameters of the terminal epoxy liquid butadiene polymer are listed in Table 3.

[0124] Comparative Example 6

[0125] Liquid butadiene polymer was prepared using the same method as in Example 1, except that ethylene oxide and epichlorohydrin were not added, resulting in liquid butadiene polymer DPB6. The structural properties of the liquid butadiene polymer are listed in Table 3.

[0126] Table 1

[0127]

[0128]

[0129] Table 1 (continued)

[0130]

[0131] Table 2

[0132] serial number <![CDATA[M n ]]> <![CDATA[M w / M n ]]> 1,2-PB / wt% <![CDATA[C-1,2-PB * / wt%]]> 1,4-PB / wt% sensibility Example 1 3059 1.07 70.3 20.5 29.7 1.92 Example 2 3064 1.10 71.9 25.4 28.1 1.94 Example 3 3094 1.09 71.4 28.1 28.6 1.96 Example 4 3042 1.12 61.9 34.2 38.1 1.92 Example 5 3076 1.09 74.2 15.4 25.8 1.92 Example 6 4270 1.11 70.7 23.8 29.3 1.9 Example 7 1807 1.09 70.1 29.8 29.9 1.98 Example 8 3054 1.18 60.3 34.5 39.7 1.94 Example 9 3066 1.17 65.3 17.4 34.7 1.92 Example 10 3049 1.16 65.2 17.6 34.8 1.9 Comparative Example 1 3068 1.16 81.8 8.9 18.2 1.9 Comparative Example 2 3040 1.21 64.8 0 35.2 1.84 Comparative Example 3 3052 1.24 60.4 0 39.6 1.86 Comparative Example 4 3064 1.17 22.6 0 77.4 1.54 Comparative Example 5 1520 1.14 76.5 17.4 23.5 0.92 Comparative Example 6 2860 1.07 70.3 20.4 29.7 /

[0133] Notes: PB represents polybutadiene block, Mn represents the number-average molecular weight of the liquid butadiene polymer, Mw / Mn represents the molecular weight distribution of the liquid butadiene polymer, 1,2-PB represents the 1,2-structure content in the liquid butadiene polymer, C-1,2-PB represents the cyclized 1,2-structure content in the liquid butadiene polymer based on the weight of 1,2-PB, and 1,4-PB represents the 1,4-structure content in the liquid butadiene polymer. * The weight of the 1,2-structure in the terminal epoxy group liquid polybutadiene polymer was used as the basis.

[0134] As can be seen from Table 2, the terminal epoxy group liquid butadiene polymer provided by the present invention has a 1,2-structural unit content between 60-74.5% by weight. Based on the weight of the 1,2-structure in the terminal acrylate group liquid polybutadiene polymer, the cyclized 1,2-structural unit content is between 15-35% by weight. It has a high 1,2-structural unit content and a high cyclized 1,2-structural unit content, high functionality, and narrow molecular weight distribution, making it an ideal adhesive for the high-frequency communication field.

[0135] Test case

[0136] The compositions PB1 to PB10 prepared in Examples 1-10 (in which 100 parts of terminal epoxy liquid butadiene polymer and 5 parts of boron trifluoride monoethylamine) were uniformly coated on the surface of copper foil with a coating thickness of 0.8 mm. They were crosslinked and cured at 150 °C for 1 hour. The peel strength, linear thermal expansion coefficient and weight loss temperature Td5 were measured. The experimental results are listed in Table 3.

[0137] Test comparison

[0138] The peel strength and coefficient of thermal expansion of compositions DPB1 to DPB3 prepared in Comparative Examples 1-6 were determined using the same method as in the test examples. The experimental results are listed in Table 3.

[0139] Table 3

[0140]

[0141] As can be seen from the results in Table 3, the polymer coating formed by the epoxy-terminated liquid polybutadiene polymer of the present invention has a high weight loss temperature Td5 and exhibits a lower coefficient of thermal expansion while maintaining high peel strength, making it an ideal adhesive for the field of high-frequency communication.

[0142] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. (1240158)

[0143] I92002BHY

[0144] Within the scope of the technical concept of this invention, various simple modifications can be made to the technical solution of this invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in this invention and are all within the protection scope of this invention.

Claims

1. A terminal epoxy group liquid butadiene polymer, characterized in that, The functionality of the terminal epoxy-based liquid butadiene polymer is 1.9-2; based on the total weight of the terminal epoxy-based liquid butadiene polymer, the content of 1,2-structural units is 60-74.5% by weight, and the content of 1,4-structural units is 25.5-40% by weight; based on the total weight of 1,2-structural units in the terminal epoxy-based liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

2. The terminal epoxy-based liquid butadiene polymer according to claim 1, wherein, The functionality of the terminal epoxy group liquid butadiene polymer is 1.9-1.96; Preferably, based on the weight of the 1,2-structural units in the terminal epoxy liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 20-30% by weight. Preferably, based on the total weight of the terminal epoxy-based liquid butadiene polymer, the content of 1,2-structural units is 65-74.5% by weight, and the content of 1,4-structural units is 25.5-35% by weight.

3. The terminal epoxy-based liquid butadiene polymer according to claim 1 or 2, wherein, The number-average molecular weight of the terminal epoxy group liquid butadiene polymer is 1000-5000 g / mol, preferably 1500-4500 g / mol, and more preferably 1800-4300 g / mol; the molecular weight distribution index of the terminal epoxy group liquid butadiene polymer is 1-1.2, preferably 1-1.

15.

4. The terminal epoxy-based liquid butadiene polymer according to any one of claims 1-3, wherein, The linear thermal expansion coefficient of the epoxy-terminated liquid butadiene polymer after curing is 50 × 10⁻⁶. -6 m / m / ℃-80×10 -6 m / m / ℃, preferably 50×10 -6 m / m / ℃-70×10 -6 m / m / ℃; Preferably, the peel strength between the coating formed by the epoxy-terminated liquid butadiene polymer and the metal substrate is 1-1.3 N / mm, more preferably 1.04-1.25 N / mm; Preferably, the weight loss temperature Td5 of the terminal epoxy-based liquid butadiene polymer after curing is 380°C to 410°C, and more preferably 395°C to 405°C.

5. A method for preparing an epoxy-terminated liquid butadiene polymer, characterized in that, The method includes: (1) In the presence of a solvent and a structure modifier, 1,3-butadiene monomer is contacted with an initiator to carry out an anionic solution polymerization reaction to obtain a polymerization reaction solution containing butadiene polymer; wherein, the contact is carried out at a temperature of 50-100°C, the structure modifier is an alkali metal alkoxide, the initiator is an organic bislithium initiator, the molar ratio of the structure modifier to the initiator is 0.1-0.8:1, and the solvent contains an alicyclic solvent; (2) The polymerization reaction solution obtained in step (1) is contacted with an epoxy end-capping agent to carry out an end-capping reaction. After the end-capping reaction is complete, a halogenated epoxy compound is added to carry out the reaction to obtain a terminal epoxy liquid butadiene polymer.

6. The method according to claim 5, wherein, The structure modifier is selected from one or more compounds shown in Formula I. RO——M(Formula I) In Formula I, R1 is a heteroatom-substituted or unsubstituted C1-C 20 Alkyl groups, or C4-C 20 cycloalkyl, M1 is an alkali metal atom; Preferably, the structure modifier is selected from at least one of sodium tetrahydrofurfuryl alcohol, sodium ethoxylate, sodium tert-pentoxylate, sodium tert-butoxylate, sodium n-hexanoate, and sodium menthol.

7. The method according to claim 5 or 6, wherein, The molar ratio of the structure modifier to the initiator is 0.2-0.6:1; Preferably, the contact is performed at a temperature of 60°C to 90°C.

8. The method according to any one of claims 5-7, wherein, The epoxy compound is at least one selected from ethylene oxide, propylene oxide and butane oxide; Preferably, the molar ratio of the epoxy compound to the initiator is 2-3:1; Preferably, the temperature of the end-capping reaction is 10-80℃, more preferably 30-70℃; and the time of the end-capping reaction is 5-90 min, more preferably 20-60 min.

9. The method according to any one of claims 5-8, wherein, The molar ratio of the halogenated epoxy compound to the initiator is 2-4:1, preferably 2.5-3.5:1; Preferably, the halogenated epoxy compound is a chloroepoxide compound, preferably selected from epichlorohydrin and / or methylepoxide; Preferably, the reaction temperature for adding the halogenated epoxy compound is 10-80℃, more preferably 30-70℃; the reaction time is 5-90 min, more preferably 20-60 min.

10. The method according to any one of claims 5-9, wherein, The solvent is an oxacycloalkane, preferably tetrahydrofuran.

11. A terminal epoxy-based liquid butadiene polymer prepared by the method according to any one of claims 5-10.

12. A composition comprising a terminal epoxy-based liquid butadiene polymer and at least one additive, wherein the terminal epoxy-based liquid butadiene polymer is the terminal epoxy-based liquid butadiene polymer according to any one of claims 1-4 and 11.

13. The composition according to claim 12, wherein, The additive contains antioxidants.

14. A polymer coating comprising the terminal epoxy liquid butadiene polymer of any one of claims 1-4 and 11, or the composition of claim 12 or 13.

15. Use of the terminal epoxy-based liquid butadiene polymer of any one of claims 1-4 and 11, or the composition of claim 12 or 13, as a crosslinking agent, adhesive, or electrical insulating material.

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