Acrylate-terminated liquid polybutadiene polymer, preparation method and application thereof, composition and application thereof, and photocuring material

Abstract

The invention relates to the field of polymer synthesis, and discloses an acrylate-terminated liquid polybutadiene polymer and a preparation method and application thereof, a composition and application thereof, and a photocuring material. The functionality degree of the acrylate-terminated liquid polybutadiene polymer is 1.8 to 2; on the basis of the total weight of the acrylate-terminated liquid polybutadiene polymer, the content of the 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 weight of the 1, 2-structural unit in the acrylate-terminated liquid polybutadiene polymer, the content of the cyclized 1, 2-structural unit is 15-35 wt%. The polymer has a cyclized structure, high 1, 2-structural unit content and uniform functionality, the heat resistance of a photocuring material formed by the polymer is remarkably improved, the volume shrinkage rate is greatly reduced, and the dimensional stability of a product is ensured.

Description

Technical Field

[0001] This invention relates to the field of polymer synthesis technology, specifically to an acrylate-terminated liquid polybutadiene polymer, its preparation method and applications, as well as compositions, applications, and photocurable materials. Background Technology

[0002] Liquid rubber is a novel liquid material with a nonpolar carbon chain as its main chain, existing in a liquid state at room temperature, and typically with a molecular weight below 10,000. Appropriate cross-linking can generate a three-dimensional network structure. Functionalized liquid rubber refers to a polymer in which various active functional groups or segments are contained at the ends or along the main chain of the liquid rubber molecule. This modified liquid rubber not only possesses the characteristics of liquid rubber but also exhibits improved overall performance due to the addition of functional groups, and has gradually replaced traditional liquid rubber as the mainstream product.

[0003] In the research of functionalized liquid rubbers, liquid butadiene polymers have attracted widespread attention from researchers. Liquid butadiene polymers are high-molecular materials polymerized from butadiene monomers, with a structure similar to liquid rubber but possessing more unique properties. Through chemical modification, photosensitive groups can be introduced into the molecular chains of liquid butadiene polymers, enabling them to rapidly cure under ultraviolet light. This photocuring technology not only improves the processing efficiency of the material but also gives it new application prospects. However, due to the rearrangement of chemical bonds and changes in molecular structure during the photocuring reaction, liquid butadiene polymers undergo volume shrinkage during curing. This shrinkage is not only affected by the density of functional groups in the reacting monomers but is also closely related to the molecular structure of each component in the resin system. A large shrinkage rate can lead to warping and deformation of the material after curing, seriously affecting the dimensional accuracy and applicability of the material.

[0004] Therefore, how to effectively reduce the volume shrinkage of liquid polybutadiene polymer during the photocuring process has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of large volume shrinkage of liquid polybutadiene polymers during photocuring in existing technologies, and to provide an acrylate-terminated liquid polybutadiene polymer, its preparation method and applications, as well as compositions, applications, and photocurable materials. The acrylate-terminated liquid polybutadiene polymer has a high content of 1,2-structural units, a cyclized structure, and acrylate-terminated ends, and exhibits high functionality. Photocurable materials formed from this acrylate-terminated liquid butadiene polymer show significantly improved heat resistance and reduced volume shrinkage, ensuring product dimensional stability.

[0006] To achieve the above objectives, a first aspect of the present invention provides an acrylate-terminated liquid polybutadiene polymer, wherein the functionality of the acrylate-terminated liquid polybutadiene polymer is 1.8-2; based on the total weight of the acrylate-terminated liquid polybutadiene 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; and based on the weight of 1,2-structural units in the acrylate-terminated liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

[0007] A second aspect of the present invention provides a method for preparing acrylate-terminated liquid polybutadiene polymer, the method comprising:

[0008] (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 polybutadiene 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;

[0009] (2) The polymerization reaction solution obtained in step (1) is contacted with an epoxy compound end-capping agent to carry out an end-capping reaction. After the end-capping reaction is complete, an acryloyl halide compound is added to carry out the reaction to obtain an acrylate-terminated liquid polybutadiene polymer.

[0010] A third aspect of the present invention provides an acrylate-terminated liquid polybutadiene polymer prepared by the above method.

[0011] A fourth aspect of the present invention provides a composition comprising an acrylate-terminated liquid polybutadiene polymer and at least one additive, wherein the acrylate-terminated liquid polybutadiene polymer is the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above.

[0012] The fifth aspect of the present invention provides a photocurable material comprising the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above.

[0013] The sixth aspect of the present invention provides the use of the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above, as an adhesive.

[0014] Through the above technical solution, the present invention has the following beneficial effects:

[0015] (1) The acrylate-terminated liquid polybutadiene polymer provided by the present invention has a high content of 1,2-structural units, as well as a cyclized structure and acrylate-terminated end, and high functionality, which endows the liquid polybutadiene polymer with excellent photo (or thermal) crosslinking reactivity, thereby improving the crosslinking density of the polymer after crosslinking and curing; and the product after crosslinking and curing has high thermal stability; the introduction of acrylate groups makes the polymer have both in-chain double bond and terminal double bond structures, becoming a liquid material with photosensitive characteristic structure, providing more selectivity for photocuring.

[0016] (2) The acrylate-terminated liquid polybutadiene polymer provided by the present invention has high functionality, preferably a narrow molecular weight distribution, and a suitable molecular weight. When applied to a photocurable system, the acrylate-terminated liquid polybutadiene polymer can significantly reduce the linear shrinkage rate of the prepared photocurable material, ensure the dimensional stability of the product, and maintain high stability even under harsh conditions. The preparation process is simple and efficient, which is conducive to actual production. Detailed Implementation

[0017] 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.

[0018] In this invention, the term "liquid polybutadiene polymer" refers to a polybutadiene polymer that is fluid at 25°C and 1 standard atmosphere.

[0019] 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.

[0020] In this invention, the term "1,4-structural unit" refers to the structural unit formed by the 1,4-polymerization of 1,3-butadiene.

[0021] 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:

[0022]

[0023] 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.

[0024] 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.

[0025] 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℃.

[0026] In this invention, the functionality of the acrylate-terminated polybutadiene polymer was determined by nuclear magnetic resonance spectroscopy.

[0027] In this invention, the volume shrinkage rate is obtained by calculation, specifically by the formula: material volume shrinkage rate = (ρ2-ρ1) / ρ2, where ρ1 and ρ2 are the densities before and after curing, respectively, and are measured by a ZMD-2 electronic density meter.

[0028] In this invention, the temperature at the maximum weight loss rate is determined using a differential scanning calorimeter. The specific testing method includes: using a TA-2980DSC differential scanning calorimeter, the temperature is increased from 25°C to 600°C at a rate of 10°C / min under a nitrogen atmosphere.

[0029] The first aspect of this invention provides an acrylate-terminated liquid polybutadiene polymer, wherein the functionality of the acrylate-terminated liquid polybutadiene polymer is 1.8-2; based on the total weight of the acrylate-terminated liquid polybutadiene 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 weight of 1,2-structural units in the acrylate-terminated liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

[0030] In some embodiments of the present invention, preferably, the functionality of the terminal acrylate-based liquid polybutadiene polymer is 1.8-2, for example, it can be 1.8, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, 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 any range of two such values, preferably 1.84-1.96. The terminal acrylate-based liquid polybutadiene polymer of the present invention has high and uniform functionality, which is beneficial for achieving a higher crosslinking density in the photocurable material formed under the same photocuring conditions.

[0031] 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 acrylate-based liquid polybutadiene 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 acrylate-based liquid polybutadiene polymer.

[0032] In some embodiments of the present invention, preferably, the content of 1,4-structural units is 25.5-40% by weight, based on the total weight of the terminal acrylate-based liquid polybutadiene 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 1,4-structural units is 25.5-35% by weight, based on the total weight of the terminal acrylate-based liquid polybutadiene 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.

[0033] 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 acrylate-based liquid polybutadiene polymer. For example, it can be 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, or any value within a range of any two values. 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 acrylate-based liquid polybutadiene polymer. In this invention, when the weights of the 1,2-structural units and the cyclized 1,2-structural units are controlled within the above-mentioned range, the overall performance of the photocurable material obtained after photocuring is better; when the content of the cyclized 1,2-structural units is less than 15% by weight, the improvement in heat resistance of the photocurable material obtained after photocuring is not significant; when the content of the cyclized 1,2-structural units is greater than 35% by weight, the crosslinking density of the photocurable material formed by the polymer decreases, and the heat resistance decreases.

[0034] In some embodiments of the present invention, preferably, the number average molecular weight of the terminal acrylate-based liquid polybutadiene polymer is 1000-5000 g / mol, more preferably 1500-4500 g / mol, and even more preferably 1800-4300 g / mol.

[0035] In some embodiments of the present invention, preferably, the molecular weight distribution index of the terminal acrylate-based liquid polybutadiene polymer is 1-1.2, more preferably 1-1.15.

[0036] In this invention, the acrylate-terminated liquid polybutadiene polymer has a molecular weight suitable for molding and a narrow molecular weight distribution, which is beneficial for the formation of a more uniform cross-linked network during the photocuring process, thereby increasing the cross-linking density of the photocurable material formed by the polymer, and also improving the dimensional stability and thermal stability of the photocurable material.

[0037] In some embodiments of the present invention, preferably, the volume shrinkage rate of the acrylate-terminated liquid polybutadiene polymer after photocuring is 2-5%.

[0038] In some embodiments of the present invention, preferably, the temperature at which the end-acrylate liquid polybutadiene polymer reaches its maximum weight loss rate after photocuring is 475-495°C, more preferably 482-492°C.

[0039] A second aspect of the present invention provides a method for preparing acrylate-terminated liquid polybutadiene polymer, the method comprising:

[0040] (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 polybutadiene 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;

[0041] (2) The polymerization reaction solution obtained in step (1) is contacted with an epoxy compound end-capping agent to carry out an end-capping reaction. After the end-capping reaction is complete, an acryloyl halide compound is added to carry out the reaction to obtain an acrylate-terminated liquid polybutadiene polymer.

[0042] In this invention, the content of 1,4-structural units, 1,2-structural units, and cyclized 1,2-structural units in the terminal acrylate-based liquid polybutadiene polymer is determined by step (1). The end-capping reaction and subsequent reactions do not affect the content of 1,4-structural units, 1,2-structural units, and cyclized 1,2-structural units in the liquid butene polymer.

[0043] In some embodiments of the present invention, preferably, the initiator is an organolithium initiator. The type of bislithium initiator is not particularly limited and can be any existing compound containing two lithium atoms capable of bidirectionally initiating anionic polymerization reactions. For example, the organolithium initiator can be selected from at least one of alkane-based bislithium, naphthalene-based bislithium, and diene-based bislithium. Specifically, the general formula of the alkane-based bislithium is LiRLi, where R is C4-C. 10 Alkyl groups, specific examples of which include, but are not limited to, at least one of Li(CH2)4Li, Li(CH2)6Li, and Li(CH2)8Li; the naphthalene-based bislithium is naphthalene lithium and / or α-methylnaphthalene lithium; 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.

[0044] In this invention, the amount of initiator can be selected based on the expected molecular weight of the terminal acrylate liquid polybutadiene polymer. Preferably, the amount of initiator is such that the number average molecular weight of the prepared terminal acrylate liquid polybutadiene 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.

[0045] In some embodiments of the present invention, preferably, the structure modifier is selected from one or more compounds represented by Formula I.

[0046] R1-O——M1(Formula I)

[0047] In Formula I, R1 is a heteroatom-substituted or unsubstituted C1-C 20 Alkyl groups, or C4-C 20 cycloalkyl groups;

[0048] M1 is an alkali metal atom; for example, it can be Li, Na or K, preferably Na.

[0049] In Formula I, the unsubstituted C1-C 20 Alkyl groups include C1-C 20 Straight-chain alkyl and C3-C 20 Branched 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.

[0050] 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.

[0051] In Equation I, C4-C 20The cycloalkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, 4-n-propylcyclohexyl, 4-n-butylcyclohexyl, or 2-isopropyl-5-methylcyclohexyl.

[0052] In some embodiments of the present invention, preferably, the structure modifier is selected from at least one of sodium tetrahydrofurfuryl alcohol, sodium tert-pentoxyl, sodium tert-butoxyl, sodium ethoxyl, sodium n-hexanolate, and sodium menthol.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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, more preferably 1.5-10% by weight, and even more preferably 2-8% 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.

[0057] 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.

[0058] 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 10-120 minutes after monomer feeding, preferably 30-80 minutes.

[0059] 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).

[0060] 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.

[0061] 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.

[0062] 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, more preferably 2-2.5:1.

[0063] 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.

[0064] In this invention, preferably, after the end-capping reaction is complete, an acryloyl halide compound is added to react and obtain an acrylate-terminated liquid polybutadiene polymer. Specifically, in this invention, an epoxy compound is added to the obtained polymerization reaction solution containing the polybutadiene polymer to perform an end-capping reaction, converting highly active polybutadiene-based lithium into less active polybutadiene-based lithium oxide; then, a substitution reaction occurs with the chlorine atoms on the added acryloyl halide compound to obtain a liquid polybutadiene polymer with acrylate-terminated groups.

[0065] In this invention, the type of acryloyl halide compound is not particularly limited, and various acryloyl halide compounds conventionally used in the art can be used in this invention. Preferably, the acryloyl halide compound is selected from at least one of acryloyl chloride, methacryloyl chloride, 2-ethylacryloyl chloride, and 2-propylacryloyl chloride.

[0066] In this invention, the amount of the acryloyl halide compound can be selected within a wide range. Preferably, the molar ratio of the acryloyl halide compound to the initiator is 6-8:1, more preferably 6.5-7.5:1.

[0067] In this invention, the reaction conditions for adding the acryloyl halide compound are not particularly limited. Preferably, the reaction temperature for adding the acryloyl halide compound is 10-80°C, more preferably 30-70°C; the reaction time is 5-90 min, more preferably 20-60 min.

[0068] In this invention, preferably, the method further includes: after the reaction of adding the acryloyl halide compound is completed, adding a terminator, and then washing, precipitating, and drying to obtain the terminal acrylate-based liquid polybutadiene polymer. More preferably, the method further includes: washing the mixture obtained by adding the terminator, and after the washed mixture is separated by precipitation and layering, separating the oil phase from the mixture to remove at least some volatile components, thereby obtaining the terminal acrylate-based liquid polybutadiene polymer.

[0069] 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.

[0070] 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 residual solvent, unreacted raw materials, and at least some metal ions. Preferably, the washing solution is an aqueous solution.

[0071] 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 mixed solution to separate into layers and separate the oil phase.

[0072] 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.

[0073] 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.

[0074] In this invention, the anionic solution polymerization reaction can be carried out by either batch polymerization or continuous polymerization, without any particular limitation.

[0075] A third aspect of the present invention provides an acrylate-terminated liquid polybutadiene polymer prepared by the above method.

[0076] The acrylate-terminated liquid polybutadiene 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 the 1,2-structural units form a cyclic structure, which endows the liquid polybutadiene polymer with excellent photo (or thermal) crosslinking reactivity, thereby increasing the crosslinking density of the polymer after curing and maintaining good stability under relatively harsh conditions; furthermore, the acrylate-terminated liquid polybutadiene polymer contains acrylate groups at both ends, and the introduction of acrylate groups makes the polymer have both in-chain double bonds and terminal double bonds, giving the liquid butadiene polymer a liquid material with photosensitive characteristics, providing more selectivity for photocuring.

[0077] A fourth aspect of the present invention provides a composition comprising an acrylate-terminated liquid polybutadiene polymer and at least one additive, wherein the acrylate-terminated liquid polybutadiene polymer is the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above.

[0078] 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 polybutadiene polymer.

[0079] The fifth aspect of the present invention provides a photocurable material comprising the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above.

[0080] In this invention, the heat resistance of the photocurable material formed by the acrylate-terminated liquid polybutadiene polymer is improved, and the volume shrinkage rate of the photocurable material is reduced, thus ensuring the dimensional stability of the product.

[0081] A sixth aspect of the present invention provides the use of the acrylate-terminated liquid polybutadiene polymer described in the first and third aspects above, or the composition described in the fourth aspect above, as an adhesive. In this invention, the adhesive is particularly suitable for use in adhesives for electronic products and optical materials.

[0082] The present invention will be described in detail below through embodiments.

[0083] Unless otherwise specified, room temperature and room temperature are both expressed as 25±3℃.

[0084] 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.

[0085] 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.

[0086] In the following examples and comparative examples, the acrylate functional groups of the polymers were determined using 1H NMR spectroscopy data.

[0087] In the following examples and comparative examples, the volume shrinkage rate was calculated using the following formula: Volume shrinkage rate = (ρ2-ρ1) / ρ2, where ρ1 and ρ2 are the densities before and after curing, respectively, and were measured using a ZMD-2 electronic density meter.

[0088] In the following examples and comparative examples, the temperature at the maximum weight loss rate was measured using a differential scanning calorimeter. The specific test method included: using a TA-2980DSC differential scanning calorimeter, the temperature was increased from 25°C to 600°C at a rate of 10°C / min under a nitrogen atmosphere.

[0089] The following examples and comparative examples involve the following chemical reagents:

[0090] Antioxidant 264, Antioxidant 168 and Antioxidant 1076 were purchased from Sinopharm Reagent Company;

[0091] Butadiene-based bislithium initiator: self-made, chemical formula C4H6Li2;

[0092] 1,3-Butadiene: Polymer grade, purchased from Yanshan Petrochemical;

[0093] Sodium tert-pentoxygenate (STA): purchased from Bailingwei Reagent Company, 1.4 mol / L tetrahydrofuran solution;

[0094] Sodium tetrahydrofurfuryl alcohol (THFOA): purchased from Inokai Reagent Company, 1.0 mol / L tetrahydrofuran solution;

[0095] Sodium menthol (SMT): purchased from Inokai Reagents, 1.0 mol / L tetrahydrofuran solution;

[0096] Ethylene oxide (EO): Purchased from Inokai Reagents, 98% purity. After distillation in the presence of calcium hydride, it was prepared into a 20 wt% tetrahydrofuran solution for use.

[0097] Propylene oxide: purchased from Inokai Reagent Company, purity 99%, distilled in the presence of calcium hydride and then prepared as a 20 wt% tetrahydrofuran solution for use;

[0098] Acryloyl chloride: purchased from Bailingwei Reagent Company, purity 97%, distilled in the presence of calcium hydride and then prepared into a 20 wt% tetrahydrofuran solution for use.

[0099] Methacrylamide chloride: purchased from Bailingwei Reagent Company, purity 98%, distilled in the presence of calcium hydride and then prepared into a 20 wt% tetrahydrofuran solution for use.

[0100] Preparation Example

[0101] The preparation process of the butadiene-based bislithium initiator is as follows:

[0102] (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.

[0103] (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.

[0104] (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).

[0105] Example 1

[0106] This embodiment illustrates the acrylate-terminated liquid polybutadiene polymer and its preparation method according to the present invention.

[0107] (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 polybutadiene polymer.

[0108] (2) Controlling the polymerization reaction temperature (as shown in Table 1), 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) is added to the polymerization reaction mixture of the liquid polybutadiene polymer obtained in step (1). The end-capping reaction is carried out at the end-capping temperature and end-capping time listed in Table 1. Then, a tetrahydrofuran solution of acryloyl halide compound (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured by pure compounds) is added. The reaction is carried out at the temperature listed in Table 1. Then, an ethanol solution is added to terminate the reaction. After washing with water and precipitation, the oil phase is subjected to vacuum distillation. An antioxidant (the specific amount is shown in Table 1, and the amounts listed in Table 1 are all measured by pure compounds) is added to the distillation residue to obtain a liquid polybutadiene polymer PB1 containing terminal acrylate groups. The structural property parameters of the liquid polybutadiene polymer with terminal acrylate groups are listed in Table 2.

[0109] Example 2-10

[0110] Examples 2-10 illustrate the terminal acrylate-based liquid polybutadiene polymer and its preparation method of the present invention.

[0111] Examples 2-10 were prepared using the same method as in Example 1 to prepare terminal acrylate-based liquid polybutadiene polymers. The difference was that steps (1) and (2) were carried out under the conditions shown in Table 1 to obtain terminal acrylate-based liquid polybutadiene polymers PB2-PB10, respectively. The structural property parameters of the terminal acrylate-based liquid polybutadiene polymers are listed in Table 2.

[0112] Comparative Example 1

[0113] The terminal acrylate-based liquid polybutadiene polymer was prepared using the same method as in Example 1, except that the polymerization temperature in step (1) was 20°C, resulting in terminal acrylate-based liquid polybutadiene polymer DPB1. The structural properties of the terminal acrylate-based liquid polybutadiene polymer are listed in Table 2.

[0114] Comparative Example 2

[0115] The terminal acrylate-based liquid polybutadiene 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 acrylate-based liquid polybutadiene polymer DPB2. The structural property parameters of the terminal acrylate-based liquid polybutadiene polymer are listed in Table 2.

[0116] Comparative Example 3

[0117] The terminal acrylate-based liquid polybutadiene 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 acrylate-based liquid polybutadiene polymer DPB3. The structural property parameters of the terminal acrylate-based liquid polybutadiene polymer are listed in Table 2.

[0118] Comparative Example 4

[0119] The terminal acrylate-based liquid polybutadiene polymer was prepared using the same method as in Example 1. The difference was that in step (1), cyclohexane was used in an equal amount to replace tetrahydrofuran to obtain the terminal acrylate-based liquid polybutadiene polymer DPB4. The structural property parameters of the terminal acrylate-based liquid polybutadiene polymer are listed in Table 2.

[0120] Comparative Example 5

[0121] The terminal acrylate-based liquid polybutadiene polymer was prepared using the same method as in Example 1. The difference was that in step (1), the dilithium initiator was replaced with an equal amount of n-butyllithium to obtain the terminal acrylate-based liquid polybutadiene polymer DPB5. The structural property parameters of the terminal acrylate-based liquid polybutadiene polymer are listed in Table 2.

[0122] Table 1

[0123]

[0124]

[0125] Table 1 (continued)

[0126]

[0127]

[0128] Table 2

[0129]

[0130] Note: PB represents polybutadiene block, Mn represents the number average molecular weight of the liquid polybutadiene polymer, Mw / Mn represents the molecular weight distribution of the liquid polybutadiene polymer, 1,2-PB represents the 1,2-structure content in the liquid polybutadiene polymer, C-1,2-PB represents the cyclized 1,2-structure content in the liquid polybutadiene polymer based on the weight of 1,2-PB, and 1,4-PB represents the 1,4-structure content in the liquid polybutadiene polymer.

[0131] As can be seen from Table 2, in a system containing alicyclic solvents, using a bifunctional initiator and under the action of an alkali metal alkoxide regulator, the content of 1,2-structural units in the terminal acrylate liquid polybutadiene polymer prepared is between 60-74.5% by weight. Based on the weight of the 1,2-structure in the terminal acrylate liquid polybutadiene polymer, the content of cyclized 1,2-structural units is between 15-35% by weight, exhibiting high functionality and narrow molecular weight distribution.

[0132] Test case

[0133] Compositions PB1 to PB10 prepared in Examples 1-10 (wherein, 100 parts of acrylate-terminated liquid polybutadiene polymer), 2.8 parts of methyl acrylate, and 3 parts of photoinitiator TPO were placed in a beaker and mixed uniformly by magnetic stirring under light-protected conditions. After standing to remove bubbles, the resulting liquid material was uniformly coated onto a glass plate with a coating thickness of 1 mm. The plate was then placed in a 500W UV lamp box with a lamp distance of 20 cm for photocuring, resulting in photocurable materials PB1 to PB10. The densities ρ1 and ρ2 of the materials before and after curing were measured using a ZMD-2 type electronic density meter. The volume shrinkage rate of the material was calculated as (ρ2-ρ1) / ρ2. The temperature at the maximum weight loss rate of the photocured material 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. The experimental results of the volume shrinkage rate and the temperature at the maximum weight loss rate of the cured material are listed in Table 3.

[0134] Test comparison

[0135] The volume shrinkage rate and the temperature at the maximum weight loss rate of compositions DPB1 to DPB5 prepared in Comparative Examples 1-5 were measured using the same method as in the test examples. The experimental results are listed in Table 3.

[0136] Table 3

[0137]

[0138]

[0139] As can be seen from the results in Table 3, the acrylate-terminated liquid polybutadiene polymer of the present invention, when applied to a photocuring system, can significantly increase the heat distortion temperature of the photocured material and reduce the volume shrinkage rate of the photocured material.

[0140] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An acrylate-terminated liquid polybutadiene polymer, characterized in that, The functionality of the terminal acrylate-based liquid polybutadiene polymer is 1.8-2; based on the total weight of the terminal acrylate-based liquid polybutadiene 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 weight of 1,2-structural units in the terminal acrylate-based liquid polybutadiene polymer, the content of cyclized 1,2-structural units is 15-35% by weight.

2. The acrylate-terminated liquid polybutadiene polymer according to claim 1, wherein, The functionality of the terminal acrylate-based liquid polybutadiene polymer is 1.84-1.96; Preferably, based on the total weight of the terminal acrylate-based liquid polybutadiene 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. Preferably, the content of cyclized 1,2-structural units is 20-30% by weight, based on the weight of 1,2-structural units in the terminal acrylate-based liquid polybutadiene polymer.

3. The acrylate-terminated liquid polybutadiene polymer according to claim 1 or 2, wherein, The number-average molecular weight of the terminal acrylate-based liquid polybutadiene 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 acrylate-based liquid polybutadiene polymer is 1-1.2, preferably 1-1.

15.

4. The acrylate-terminated liquid polybutadiene polymer according to any one of claims 1-3, wherein, The volume shrinkage rate of the acrylate-terminated liquid polybutadiene polymer after photocuring is 2-5%; Preferably, the temperature at which the end-acrylate liquid polybutadiene polymer reaches its maximum weight loss rate after photocuring is 475-495°C.

5. A method for preparing acrylate-terminated liquid polybutadiene 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 polybutadiene 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 compound end-capping agent to carry out an end-capping reaction. After the end-capping reaction is complete, an acryloyl halide compound is added to carry out the reaction to obtain an acrylate-terminated liquid polybutadiene polymer.

6. The method according to claim 5, wherein, The structure modifier is selected from one or more compounds shown in Formula I. RO——M1 (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 tert-pentoxyl, sodium tert-butoxyl, sodium n-hexanolate, sodium ethoxyl, 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, more preferably 2-2.5:1; 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 acryloyl halide compound is selected from at least one of acryloyl chloride, methacryloyl chloride, 2-ethylacryloyl chloride, and 2-propylacryloyl chloride; Preferably, the molar ratio of the acryloyl halide compound to the initiator is 6-8:1, more preferably 6.5-7.5:1; Preferably, the reaction temperature for adding the acryloyl halide 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. An acrylate-terminated liquid polybutadiene polymer prepared by the method according to any one of claims 5-10.

12. A composition comprising an acrylate-terminated liquid polybutadiene polymer and at least one additive, wherein the acrylate-terminated liquid polybutadiene polymer is the acrylate-terminated liquid polybutadiene 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 photocurable material comprising the terminal acrylate liquid polybutadiene polymer of any one of claims 1-4 and 11, or the composition of claim 12 or 13.

15. Use of the terminal acrylate liquid polybutadiene polymer of any one of claims 1-4 and 11, or the composition of claim 12 or 13, as an adhesive.

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