Reactive curing agent

Abstract

Provided is a reactive curing agent that has improved solubility in methyl ethyl ketone and can improve the heat resistance of thermosetting resin compositions.　The present invention provides a reactive curing agent comprising a copolymer containing an aromatic vinyl-based monomer unit, an unsaturated acid anhydride monomer unit, and a maleimide-based monomer unit, wherein the copolymer has a weight average molecular weight of 10,000 or more and less than 90,000, and contains 3.0 mass% or more and less than 49.0 mass% of the maleimide-based monomer unit when the total amount of the monomer units constituting the copolymer is taken as 100 mass%.

Description

[Technical Field]

[0001] This invention relates to a reactive curing agent. [Background technology]

[0002] Copper-clad laminates (CCLs) are known as printed circuit boards that provide electrical connections / insulation between electronic components constituting a circuit, as well as mechanical placement / fixation of components. CCLs are obtained by impregnating glass fibers with a thermosetting resin composition containing epoxy resin or polyphenylene ether resin and a reactive curing agent to obtain a prepreg, which is a semi-cured resin sheet. Multiple such prepregs are then sandwiched between copper foils, stacked, and heat-pressed together. Styrene-maleic anhydride copolymer (SMA) is often used as a reactive curing agent due to its low dielectric loss. It is also known that styrene (St)-maleic anhydride (MAH)-N-phenylmaleimide (NPMI) copolymer can be used as a reactive curing agent (Patent Documents 1-4). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication 2022-508173 [Patent Document 2] Japanese Patent Publication No. 2020-169276 [Patent Document 3] Patent No. 5474561 [Patent Document 4] Patent No. 4807434 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention aims to provide a reactive curing agent that has improved solubility in methyl ethyl ketone (MEK) and can improve the heat resistance of thermosetting resin compositions. [Means for solving the problem]

[0005] As a result of our investigations, we have found that by using a reactive curing agent containing a copolymer containing aromatic vinyl monomer units, unsaturated acid anhydride monomer units, and maleimide monomer units, wherein the weight-average molecular weight of the copolymer is 10,000 or more and less than 90,000, and the copolymer contains 3.0% or more and less than 49.0% by mass of the maleimide monomer units when the total amount of monomer units contained in the copolymer is taken as 100% by mass, it is possible to improve solubility in MEK and also improve the heat resistance of the thermosetting resin composition. In other words, the present invention is [1] A reactive curing agent comprising a copolymer containing aromatic vinyl monomer units, unsaturated acid anhydride monomer units, and maleimide monomer units, The weight-average molecular weight of the copolymer is 10,000 or more and less than 90,000. The copolymer contains, when the total amount of monomer units contained in the copolymer is 100% by mass, 3.0% by mass or more and less than 49.0% by mass of the maleimide monomer units. Reactive curing agent. [2] The copolymer contains 3.0 to 30.0% by mass of the maleimide monomer units, when the total amount of monomer units contained in the copolymer is 100% by mass. [1] The reactive curing agent described above. [3] The copolymer is defined as having a total monomer unit content of 100% by mass, The aforementioned aromatic vinyl monomer units amount to 45.0 to 96.9% by mass. The aforementioned unsaturated anhydride monomer units amount to 0.1 to 25% by mass, and Other monomer units include 0.0 to 20.0% by mass. [2] The reactive curing agent described above. [4] The number of unsaturated acid anhydride monomer units contained in each molecular chain of the copolymer is 2 to 25. A reactive curing agent as described in any one of [1] to [3]. [5] The glass transition temperature of the copolymer is 125 to 200°C. A reactive curing agent as described in any one of [1] to [4]. [6] The weight-average molecular weight of the copolymer is 15,000 to 80,000. A reactive curing agent described in any one of [1] to [5]. [7] The weight-average molecular weight of the copolymer is 20,000 to 70,000. A reactive curing agent described in any one of [1] to [5]. Regarding. [Effects of the Invention]

[0006] By employing the reactive curing agent of the present invention, solubility in MEK is improved. Furthermore, the heat resistance of the thermosetting resin composition can be improved. For this reason, it is suitably used in applications requiring heat resistance, such as copper-clad laminates. [Modes for carrying out the invention]

[0007] <Explanation of Terms> In this specification, the description "A to B" means that it is greater than or equal to A and less than or equal to B.

[0008] The embodiments of the present invention will be described in detail below. The present invention is not limited thereto, and various modifications are possible without departing from its essence. The various features shown in the embodiments below can be combined with each other. Furthermore, each feature constitutes an invention independently.

[0009] <Copolymer contained in reactive curing agents> The reactive curing agent according to this embodiment includes a copolymer containing aromatic vinyl monomer units, unsaturated acid anhydride monomer units, and maleimide monomer units. The monomer units contained in the copolymer are described below.

[0010] <Aromatic vinyl monomer units> Examples of the aromatic vinyl monomer from which the aromatic vinyl monomer unit contained in the copolymer according to this embodiment is derived include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, and the like. Among these, styrene is preferred from the viewpoint of the solubility of the copolymer in MEK. The aromatic vinyl monomer may be used alone or in combination of two or more.

[0011] When the total of the monomer units contained in the copolymer is 100% by mass, the copolymer according to this embodiment preferably contains 45.0 to 96.9% by mass of the aromatic vinyl monomer unit, more preferably 45.0 to 89.9% by mass, still more preferably 55.0 to 85.0% by mass, and particularly preferably 60.0 to 80.0% by mass. Specifically, for example, 45.0, 50.0, 55.0, 60.0, 65.0, 70.0, 74.0, 76.0, 78.0, 80.0, 82.0, 84.0, 85.0, 86.0, 88.0, 89.9, or 96.9% by mass is preferable, and it may also be within the range between any two of the values exemplified herein. When the content of the aromatic vinyl monomer unit is 45.0% by mass or more, the solubility of the copolymer in MEK is improved, and when it is 96.9% by mass or less, more maleimide monomer units that can contribute to the improvement of heat resistance can be contained in the copolymer, so that the heat resistance of the thermosetting resin composition containing the copolymer is improved. The content of the aromatic vinyl monomer unit is 13 a value measured by C-NMR. When the aromatic vinyl monomer units are used in combination, the content of the aromatic vinyl monomer units means the total amount of the aromatic vinyl monomer units used in combination.

[0012] <Unsaturated acid anhydride monomer unit> Examples of unsaturated acid anhydride monomers derived from the unsaturated acid anhydride monomer units contained in the copolymer according to this embodiment include maleic acid anhydride, itaconic acid anhydride, citraconic acid anhydride, and aconitic acid anhydride. Among these, maleic acid anhydride is preferred from the viewpoint of imparting curability to the thermosetting resin composition containing the copolymer. The unsaturated acid anhydride monomer may be used alone or in combination of two or more types.

[0013] The copolymer according to this embodiment preferably contains 0.1 to 25% by mass of unsaturated acid anhydride monomer units when the total amount of monomer units contained in the copolymer is 100% by mass, more preferably 0.1 to 8.0% by mass, even more preferably 0.1 to 6.0% by mass, and particularly preferably 0.1 to 4.0% by mass. Specifically, for example, it is preferably 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 10, 15, 20, or 25% by mass, and may be within the range of any two of the values ​​exemplified here. If the content of unsaturated acid anhydride monomer units is 0.1% by mass or more, the curability of the thermosetting resin composition containing the copolymer is improved, and if it is 25% by mass or less, the thermal stability of the copolymer and the hygroscopicity and thermal stability of the thermosetting resin composition containing the copolymer are improved. The content of unsaturated acid anhydride monomer units is, 13 These values ​​were measured by 13C-NMR. Furthermore, when unsaturated acid anhydride monomer units are used in combination, the content of unsaturated acid anhydride monomer units refers to the total amount of unsaturated acid anhydride monomer units used in combination.

[0014] <Maleimide-based monomer units> Maleimide monomers derived from maleimide monomer units contained in the copolymer according to this embodiment include, for example, N-alkyl maleimides such as N-methylmaleimide, N-butylmaleimide, and N-cyclohexylmaleimide, and N-aryl maleimides such as N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, and N-tribromophenylmaleimide. Among these, N-arylmaleimide is preferred from the viewpoint of thermal stability of the copolymer, and N-phenylmaleimide is even more preferred. Maleimide monomers may be used individually or in combination of two or more types. To incorporate maleimide monomer units into a copolymer, for example, a copolymer obtained by copolymerizing a raw material consisting of unsaturated acid anhydride monomer units with another monomer can be imidized with ammonia or a primary amine. Alternatively, a raw material consisting of maleimide monomers can be copolymerized with another monomer.

[0015] The copolymer according to this embodiment contains 3.0% by mass or more and less than 49.0% by mass of maleimide monomer units when the total amount of monomer units contained in the copolymer is taken as 100% by mass, preferably 3.0 to 30.0% by mass, more preferably 14.0 to 28.0% by mass, and even more preferably 18.0 to 26.0% by mass. Specifically, for example, it is preferably 3.0, 5.0, 8.0, 10.0, 12.5, 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 35.0, 40.0, 45.0, 48.0, or 48.9% by mass, and may be within the range of any two of the values ​​exemplified here. If the maleimide monomer unit content is 3.0% by mass or more, the heat resistance of the thermosetting resin composition containing the copolymer is improved, and if it is less than 49.0% by mass, the solubility of the copolymer in MEK is improved. The maleimide monomer unit content is 13 These values ​​were measured by 13C-NMR. When maleimide monomer units are used in combination, the content of maleimide monomer units refers to the total amount of maleimide monomer units used in combination.

[0016] <Other monomer units> The copolymer according to this embodiment may be copolymerized with other copolymerizable monomers other than aromatic vinyl monomers, unsaturated acid anhydride monomers, and maleimide monomers, as long as they do not hinder the effects of the present invention. Examples of other monomers copolymerizable with the copolymer according to this embodiment include vinyl cyanide monomers, acrylic acid ester monomers, methacrylic acid ester monomers, vinyl carboxylic acid monomers, acrylamides, and methacrylic acid amides. Among these, vinyl cyanide monomers and methacrylic acid ester monomers are preferred from the viewpoint of affinity with epoxy resins. Examples of vinyl cyanide monomers include acrylonitrile, methacrylonitrile, ethacrylonitrile, and fumaronitrile. Examples of acrylic acid ester monomers include methyl acrylic acid ester, ethyl acrylic acid ester, and butyl acrylic acid ester. Examples of methacrylate monomers include methyl methacrylate and ethyl methacrylate. Examples of vinyl carboxylic acid monomers include acrylic acid and methacrylic acid. Other monomers copolymerizable with the copolymer may be used individually or in combination of two or more types.

[0017] Such copolymerizable other monomers can be copolymerized to the extent that they do not impede the effects of the present invention. However, from the viewpoint of balancing affinity with epoxy resin and solubility in MEK, it is preferable that the copolymer contains 0.0 to 20.0% by mass of other monomer units, more preferably 0.1 to 10.0% by mass, and even more preferably 0.5 to 5.0% by mass, when the total amount of monomer units contained in the copolymer is 100% by mass. Specifically, for example, it is preferable that the amount is 0.0, 0.5, 1.0, 2.0, 5.0, 10.0, 15.0, or 20.0% by mass, and may be within the range of any two of the values ​​exemplified here. When other monomer units are included, the affinity with epoxy resin improves, and if the amount is 20.0% by mass or less, the solubility in MEK improves. The content of other monomer units is 13 These values ​​were measured by 13C-NMR. Furthermore, when other monomer units are used in combination, this refers to the total amount of those other monomer units used.

[0018] <Additives contained in reactive curing agents> The reactive curing agent according to this embodiment may contain additives as described below, to the extent that they do not impair the effects of the present invention. After polymerization of the copolymer contained in the reactive curing agent is complete, the polymerization solution may optionally contain heat stabilizers such as hindered phenol compounds, lactone compounds, phosphorus compounds, and sulfur compounds; light stabilizers such as hindered amine compounds and benzotriazole compounds; lubricants, plasticizers, colorants, antistatic agents, and mineral oil. The amount of these additives is preferably less than 0.2 parts by mass per 100 parts by mass of the total monomer units. These additives may be used individually or in combination of two or more types.

[0019] <Copolymer Manufacturing> The polymerization mode of the copolymer contained in the reactive curing agent according to this embodiment can be, for example, solution polymerization or bulk polymerization. Solution polymerization is preferred from the viewpoint that a copolymer with a more uniform copolymer composition can be obtained by polymerization while performing additive addition, etc. The solvent for solution polymerization is preferably nonpolymerizable from the viewpoint that by-products are less likely to form and adverse effects are minimized. Examples include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetophenone; ethers such as tetrahydrofuran and 1,4-dioxane; aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. Methyl ethyl ketone and methyl isobutyl ketone are preferred from the ease of solvent removal during defoliation and recovery of the copolymer. The polymerization process can be a continuous polymerization, batch (batch) or semi-batch process.

[0020] The method for producing the copolymer according to this embodiment is not particularly limited, but it is preferably obtained by radical polymerization, and the polymerization temperature is preferably in the range of 80 to 150°C. The polymerization initiator is not particularly limited, but for example, known azo compounds such as azobisisobutyronitrile, azobiscyclohexanecarbonilate, azobismethylpropionitrile, and azobismethylbutyronitrile, or known organic peroxides such as benzoyl peroxide, t-butyl peroxybenzoate, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, di-t-butyl peroxide, dicumyl peroxide, and ethyl-3,3-di-(t-butylperoxy)butyrate can be used, and one or more of these may be used in combination. From the viewpoint of controlling the polymerization reaction rate and polymerization rate, it is preferable to use azo compounds or organic peroxides with a 10-hour half-life of 70 to 120°C. The amount of polymerization initiator used is not particularly limited, but it is preferably 0.1 to 1.5% by mass per 100% by mass of total monomer units, and more preferably 0.1 to 1.0% by mass. If the amount of polymerization initiator used is 0.1% by mass or more, a sufficient polymerization rate can be obtained, which is preferable. If the amount of polymerization initiator used is 1.5% by mass or less, the polymerization rate can be suppressed, making it easier to control the reaction and obtain the target molecular weight.

[0021] A chain transfer agent can be used in the production of the copolymer according to this embodiment. The chain transfer agent used is not particularly limited, but examples include n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, ethyl thioglycolate, limonene, terpinolene, etc. The amount of chain transfer agent used is not particularly limited as long as the target molecular weight can be obtained, but it is preferably 0.01 to 2.0% by mass, and more preferably 0.1 to 1.5% by mass, based on 100% by mass of total monomer units. If the amount of chain transfer agent used is 0.01% to 1.2% by mass, the target molecular weight can be easily obtained.

[0022] Methods for introducing maleimide monomer units into the copolymer according to this embodiment include copolymerization with maleimide monomers, aromatic vinyl monomers, and other monomers (direct method), or prepolymerization with unsaturated acid anhydride monomers, aromatic vinyl monomers, and other monomers, and then further reaction of the unsaturated acid anhydride groups with ammonia or a primary amine to convert the unsaturated acid anhydride groups into maleimide monomer units (post-imidization method). The post-imidization method is preferred because it reduces the amount of residual maleimide monomers in the copolymer.

[0023] Primary amines used in the post-imidization method include, for example, alkylamines such as methylamine, ethylamine, n-propylamine, iso-propylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, and decylamine, as well as chlor- or brom-substituted alkylamines and aromatic amines such as aniline, toluidine, and naphthylamine. Among these, aniline and cyclohexylamine are preferred. These primary amines may be used individually or in combination of two or more. The amount of primary amine added is not particularly limited, but is preferably 0.7 to 1.1 molar equivalents, and more preferably 0.85 to 1.05 molar equivalents, relative to the unsaturated acid anhydride group. An amount of 0.7 molar equivalents or more relative to the unsaturated acid anhydride monomer units in the crude product raw material is preferred because it results in good thermal stability of the copolymer. An amount of 1.1 molar equivalents or less is preferred because it reduces the amount of primary amine remaining in the copolymer.

[0024] A catalyst may be used when introducing maleimide monomer units by post-imidation. The catalyst can improve the dehydration and ring-closing reaction in the reaction between ammonia or a primary amine and an unsaturated acid anhydride group, particularly in the reaction from an unsaturated acid anhydride group to a maleimide group. The type of catalyst is not particularly limited, but for example, a tertiary amine can be used. Examples of tertiary amines are not particularly limited, but include trimethylamine, triethylamine, tripropylamine, tributylamine, N,N-dimethylaniline, and N,N-diethylaniline. The amount of tertiary amine added is not particularly limited, but it is preferably 0.01 molar equivalents or more relative to the unsaturated acid anhydride group. The temperature of the imidation reaction in this invention is preferably 100 to 250°C, and more preferably 120 to 200°C. If the temperature of the imidation reaction is 100°C or higher, the reaction rate is sufficiently fast and is preferable from the viewpoint of productivity. If the temperature of the imidation reaction is 250°C or lower, it is preferable because it can suppress the deterioration of physical properties due to thermal degradation of the copolymer.

[0025] A known method can be used to remove volatile components such as the solvent used in solution polymerization and unreacted monomers from the solution after solution polymerization of the copolymer or after post-imidization (devolatilization method). For example, a vacuum devolatilization tank with a heater or a devolatilization extruder with a vent can be used. The devolatilized molten copolymer is transferred to a granulation process, where it is extruded in strand form through a porous die and processed into pellets using a cold-cut method, an air-hot-cut method, or a water-hot-cut method. The resulting pellets can be processed into a powder by a grinding process. Powdering the copolymer has the advantage of increasing the dissolution rate when incorporated into a thermosetting resin composition. If the weight-average molecular weight of the copolymer is reduced, the extruded copolymer may be recovered and ground into a powder without going through the pelletization process. There are no particular limitations on the grinding method, and known grinding techniques can be used. Suitable grinding devices include rotary blade grinders, turbo mill grinders, turbo disc mill grinders, turbo cutter grinders, jet mill grinders, impact grinders, hammer grinders, and vibratory grinders.

[0026] <Weight-average molecular weight (Mw) of copolymer> The weight-average molecular weight (Mw) of the copolymer according to this embodiment is 10,000 or more and less than 90,000, preferably 15,000 to 80,000, more preferably 20,000 to 70,000, and even more preferably 30,000 to 70,000. Specifically, for example, it is preferably 1, 2, 3, 4, 5, 6, 7, 8, or 89,000, and may be within the range of any two of the values ​​exemplified here. If the weight-average molecular weight (Mw) of the copolymer is 10,000 or more, the amount of chain transfer agent used in the polymerization step of the copolymer is reduced, so the amount of VOCs contained in the resulting copolymer can be reduced, and if it is less than 90,000, the solubility of the copolymer in MEK can be improved. To control the weight-average molecular weight (Mw) of a copolymer, methods include adjusting the polymerization temperature, polymerization time, and the amount of polymerization initiator added, as well as adjusting the solvent concentration and the amount of chain transfer agent added.

[0027] The weight-average molecular weight (Mw) of a copolymer is a polystyrene-converted value measured by gel permeation chromatography (GPC), and can be measured, for example, under the following conditions. Device name: SYSTEM-21 Shodex (manufactured by Showa Denko Corporation) Column: Three PL gel MIXED-B columns in series Temperature: 40℃ Detection: Differential refractive index Solvent: tetrahydrofuran Concentration: 2% by mass Calibration curve: Prepared using standard polystyrene (PS) (manufactured by PL Co., Ltd.).

[0028] <Number-average molecular weight (Mn) of copolymer> The number-average molecular weight (Mn) of the copolymer according to this embodiment is preferably 10,000 to 40,000, and more preferably 20,000 to 40,000. Specifically, for example, it is preferably 1, 2, 3, or 40,000, and may be within the range of any two of the values ​​exemplified herein. If the number-average molecular weight (Mn) of the copolymer is 10,000 or more, the amount of chain transfer agent used in the polymerization process of the copolymer is reduced, so the amount of VOCs contained in the resulting copolymer can be reduced, and if it is 40,000 or less, the solubility of the copolymer in MEK and the curability of the thermosetting resin composition containing the copolymer can be improved. To control the number-average molecular weight (Mn) of a copolymer, methods include adjusting the polymerization temperature, polymerization time, and the amount of polymerization initiator added, as well as adjusting the solvent concentration and the amount of chain transfer agent added. The number-average molecular weight (Mn) of the copolymer is a polystyrene-converted value measured by gel permeation chromatography (GPC), and can be measured, for example, under the same conditions as the weight-average molecular weight (Mw) described above.

[0029] <Number of unsaturated acid anhydride monomer units per molecular chain of copolymer> The number of unsaturated acid anhydride monomer units per molecular chain of the copolymer according to this embodiment is preferably 2 to 25, more preferably 3 to 16, and even more preferably 4 to 12. Specifically, the number of unsaturated acid anhydride monomer units per molecular chain of the copolymer is preferably 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 20, or 25, and may be within the range of any two of the values ​​exemplified here. If the number of unsaturated acid anhydride monomer units per molecular chain of the copolymer is 2 or more, the curability of the thermosetting resin composition containing the copolymer is improved, and if it is 25 or less, the balance between the thermal decomposition properties of the copolymer and the curability of the thermosetting resin composition containing the copolymer is improved. To control the number of unsaturated acid anhydride monomer units per molecular chain of a copolymer, methods such as adjusting the content of unsaturated acid anhydride monomer units in the copolymer or adjusting the number-average molecular weight (Mn) of the copolymer can be used.

[0030] The number of unsaturated acid anhydride monomer units (N) per molecular chain of a copolymer can be calculated using the following formula (1) from the content of unsaturated acid anhydride monomer units in the copolymer (A, unit: mass%), where the total amount of monomer units contained in the copolymer is taken as 100% by mass, and the number-average molecular weight (Mn) of the copolymer. N=(A / 100)×Mn / 98 Formula (1)

[0031] <Glass transition temperature (Tg) of copolymers> The glass transition temperature (Tg) of the copolymer according to this embodiment is preferably 125°C to 200°C, more preferably 130°C to 190°C, and even more preferably 135°C to 180°C. Specifically, for example, it is preferably 125, 130, 135, 140, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, or 200°C, and may be within the range of any two of the values ​​exemplified herein. If the glass transition temperature (Tg) of the copolymer is 125°C or higher, the heat resistance of the thermosetting resin composition containing the copolymer is improved, and if it is 200°C or lower, the solubility of the copolymer in MEK can be improved. The glass transition temperature (Tg) of a copolymer can be controlled, for example, by adjusting the content of maleimide monomer units contained in the copolymer or the weight-average molecular weight of the copolymer.

[0032] The glass transition temperature is the intermediate glass transition temperature (Tmg) measured by DSC in accordance with JIS K-7121, and is the measured value under the measurement conditions described below. Device name: Robot DSC6200 manufactured by Seiko Instruments Inc. Heating rate: 10°C / min

[0033] <Amount of residual aromatic vinyl monomers in copolymer> The amount of residual aromatic vinyl monomers in the copolymer according to this embodiment is preferably 0 to 500 ppm, more preferably 0 to 400 ppm, and even more preferably 0 to 300 ppm. Specifically, for example, it is preferably 1, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 50 ppm or less. If the amount of residual aromatic vinyl monomers in the copolymer is 500 ppm or less, the amount of VOCs contained in the copolymer can be reduced. The amount of residual aromatic vinyl monomers in the copolymer is measured under the following conditions after pretreatment: 0.3-0.4 g of the copolymer is weighed into a 50 mL Erlenmeyer flask, 10 mL of DMF containing an internal standard (cyclopentanol) is added and dissolved, and then the amount is measured. Device name: GC-12A (manufactured by Shimadzu Corporation) Detector: FID Column: 3m glass column (packing material: liquid phase PEG20M + TCEP (15 + 5)) Temperature: INJ 150℃, DET 150℃, Column 115℃ Injection volume: 1μL The amount of residual aromatic vinyl monomers in the copolymer can be reduced, for example, by reducing the amount of chain transfer agent used in the polymerization process.

[0034] <Amount of residual maleimide monomers in the copolymer> The amount of residual maleimide monomers in the copolymer according to this embodiment is preferably 0 to 500 ppm, more preferably 0 to 400 ppm, and even more preferably 0 to 300 ppm. Specifically, for example, it is preferably 1, 50, 100, 150, 200, 250, 300, 350, 400, 450, or 500 ppm or less. If the amount of residual maleimide monomers in the copolymer is 500 ppm or less, the amount of VOCs contained in the copolymer can be reduced. The amount of residual maleimide monomer in the copolymer is measured under the following conditions. Device name: GC-2010 (manufactured by Shimadzu Corporation) Column: Capillary column DB-5MS (phenylalene polymer) Temperature: Inlet 280°C, Detector 280°C The analysis is performed with a column temperature of 80°C (initial). (Temperature-based analysis conditions) 80℃: Hold for 12 minutes 80-280℃: Heat at a rate of 20℃ / min for 10 minutes 280℃: Hold for 10 minutes Detector: FID Procedure: Dissolve 0.5 g of the sample in 5 ml of 1,2-dichloroethane solution (0.014 g / L) containing undecane (internal standard). Then, add 5 ml of n-hexane and shake with a shaker for 10-15 minutes to precipitate. After the polymer has precipitated, inject only the supernatant into the GC. From the peak area of ​​the obtained monomer, calculate the quantitative value using the coefficient obtained from the internal standard. The amount of residual maleimide monomers in the copolymer can be reduced, for example, by employing a post-imidization method in the production of the copolymer.

[0035] <Properties of copolymers> <Thermal stability of copolymers> The copolymer according to this embodiment exhibits excellent thermal stability. Here, the thermal stability of the copolymer is an index evaluated by the 5% mass decrease temperature determined by thermogravimetric analysis (TGA), and is measured under a nitrogen atmosphere at a heating rate of 5°C / min. If the 5% mass decrease temperature of the copolymer, as determined by thermogravimetric analysis (TGA), is high, and the copolymer exhibits excellent thermal stability, then the reactive curing agent containing the copolymer will also exhibit excellent thermal stability.

[0036] <Solubility of copolymers in MEK> The copolymer according to this embodiment exhibits excellent solubility in ethyl methyl ketone (MEK). Here, the solubility of the copolymer in MEK is defined by the weight percentage concentration (wt%) of the MEK solution obtained by dissolving the maximum amount of copolymer that can dissolve in 10 g of MEK at 23°C. Specifically, at 23°C, a predetermined amount of copolymer is added to MEK in three separate additions, and the copolymer is dissolved by stirring. The second addition of copolymer is performed one hour after the first addition, and the third addition is performed one hour after the second addition. After the third addition, it is confirmed that all added copolymer is completely dissolved within four hours. The amount of copolymer to be dissolved is varied to determine the maximum amount of copolymer that can be dissolved, and the weight percentage (wt%) of the MEK solution when this maximum amount of copolymer is dissolved is calculated.

[0037] The copolymer according to this embodiment exhibits excellent solubility in ethyl methyl ketone (MEK), and therefore, the reactive curing agent obtained by incorporating this copolymer also exhibits excellent solubility in MEK. For this reason, when the reactive curing agent according to this embodiment is used, for example, as a reactive curing agent for a thermosetting resin composition impregnated with glass fibers in the production of copper-clad laminate (CCL) prepregs, the amount of copolymer incorporated into the thermosetting resin composition can be increased. By increasing the amount of copolymer incorporated into the thermosetting resin composition, it is possible to improve the properties of the thermosetting resin composition, such as heat resistance, by utilizing the properties of the various monomer units contained in the copolymer. Furthermore, if the copolymer exhibits excellent solubility in MEK, it can also be expected to exhibit excellent solubility in solvents other than MEK used in the production of CCL, such as acetone, toluene, and cyclohexanone.

[0038] <Thermosetting resin composition containing a reactive curing agent> A thermosetting resin composition can be obtained by blending the reactive curing agent according to this embodiment with a thermosetting resin. As the thermosetting resin, for example, a resin used to impregnate glass fibers in the production of copper-clad laminate (CCL) prepregs can be used, such as epoxy resin, cyanate resin, bismaleimide resin, etc. The thermosetting resin composition may contain other resins, additives, etc., as needed.

[0039] <Other resins> The thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment may contain elastomers such as butadiene rubber, isoprene rubber, acrylate rubber, graft copolymers containing these, and hydrogenated graft copolymers, to the extent that they do not impair the effects of the present invention, for the purpose of improving the peel strength between the thermosetting resin composition and the metal foil.

[0040] <Additives> In the thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment, a curing agent such as a styrene-maleic anhydride copolymer may be added to the reactive curing agent according to the present invention to improve curability, within a range that does not impair the effects of the present invention. Furthermore, for the purpose of promoting the curing properties of the curing agent, amine-based curing accelerators, imidazole-based curing accelerators, phosphorus-based curing accelerators, etc., may be added to the extent that they do not impair the effects of the present invention. Furthermore, for the purpose of imparting flame retardancy to the thermosetting resin composition, flame retardants such as phosphate ester-based flame retardants like tricresyl phosphate and triphenyl phosphate, and inorganic substances such as red phosphorus, antimony trioxide, aluminum hydroxide, and magnesium hydroxide may be added within a range that does not impair the effects of the present invention. Furthermore, inorganic fillers such as silica, mica, talc, glass short fibers, glass fine powder, and hollow glass may be incorporated to reduce the coefficient of thermal expansion and increase the modulus of elasticity, within limits that do not impair the effects of the present invention.

[0041] <Manufacturing of thermosetting resin compositions> The thermosetting resin composition is obtained by dissolving the reactive curing agent, thermosetting resin, and other resins and additives according to this embodiment in an organic solvent and mixing them. Examples of such organic solvents include ketones such as MEK, cyclohexanone, and methyl isobutyl ketone.

[0042] <Properties of thermosetting resin compositions> <Heat resistance of thermosetting resin compositions> The thermosetting resin composition obtained by incorporating a reactive curing agent into this embodiment exhibits excellent heat resistance. Here, the heat resistance of the thermosetting resin composition is a property evaluated by the glass transition temperature (Tg) measured by DSC in accordance with JIS C 6481. Here, the glass transition temperature (Tg) is the intermediate glass transition temperature (Tmg), and is the measured value under the measurement conditions described below. Device name: Robot DSC6200 manufactured by Seiko Instruments Inc. Heating rate: 10°C / min

[0043] The thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment employs a reactive curing agent with improved solubility in MEK, thus increasing the amount of reactive curing agent that can be incorporated into the thermosetting resin composition. The reactive curing agent according to this embodiment contains maleimide monomer units that can contribute to improving the heat resistance of the thermosetting resin composition, resulting in superior heat resistance of the thermosetting resin composition.

[0044] Furthermore, even when a styrene-maleic anhydride copolymer is used in combination with the reactive curing agent according to this embodiment as a curing agent for thermosetting resins, the thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment exhibits excellent heat resistance. The thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment employs a reactive curing agent with improved solubility in MEK, thus increasing the amount of reactive curing agent that can be incorporated into the thermosetting resin composition. This makes it possible to reduce the amount of styrene-maleic anhydride copolymer used in combination with the thermosetting resin composition. Since the styrene-maleic anhydride copolymer has a lower glass transition temperature than the reactive curing agent according to this embodiment, the amount of copolymer incorporated into the thermosetting resin composition can be reduced, resulting in superior heat resistance of the thermosetting resin composition.

[0045] <Curing properties of thermosetting resin compositions> The thermosetting resin composition obtained by incorporating a reactive curing agent in this embodiment can also be made to have excellent curability by adjusting the number-average molecular weight of the copolymer. The curability of a thermosetting resin composition is a property evaluated by the degree of resin curing, which is calculated by measuring the glass transition temperature (Tg) using the TMA method under the following measurement conditions, in accordance with JIS C 6481. Equipment name: Q400, manufactured by T.A. Instruments Japan Co., Ltd. Heating rate: 5°C / min The thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment employs a reactive curing agent with improved solubility in MEK, thus increasing the amount of reactive curing agent that can be incorporated into the thermosetting resin composition. The reactive curing agent according to this embodiment contains unsaturated acid anhydride monomer units that can react with the thermosetting resin in the thermosetting resin composition, thereby improving the curability of the thermosetting resin composition.

[0046] <Moisture absorption resistance of cured thermosetting resin compositions> The cured product of the thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment can also be made to have excellent moisture resistance by reducing the amount of unsaturated acid anhydride monomer units in the copolymer. The moisture resistance of a cured thermosetting resin composition is a property evaluated by its water absorption rate, measured in accordance with JIS C 6481. In particular, when using a styrene-maleic anhydride copolymer in combination with the reactive curing agent according to this embodiment, the thermosetting resin composition obtained by incorporating the reactive curing agent according to this embodiment employs a reactive curing agent with improved solubility in MEK, thus increasing the amount of reactive curing agent that can be incorporated into the thermosetting resin composition. As a result, it becomes possible to reduce the amount of styrene-maleic anhydride copolymer incorporated into the thermosetting resin composition. Since the styrene-maleic anhydride copolymer has higher hygroscopicity than the reactive curing agent according to this embodiment, reducing the amount incorporated into the thermosetting resin composition results in superior hygroscopicity resistance of the thermosetting resin composition. [Examples]

[0047] The details will be explained below using examples, but the present invention is not limited to the following examples. In the table, St represents styrene, AN represents acrylonitrile, NPMI represents N-phenylmaleimide, MAH represents maleic anhydride, and MEK represents methyl ethyl ketone.

[0048] <Example 1: Synthesis of copolymer (P-1)> 83 parts by mass of styrene, 1 part by mass of maleic anhydride, 0.6 parts by mass of α-methylstyrene dimer, and 26 parts by mass of methyl ethyl ketone were charged into an autoclave with a volume of approximately 120 liters equipped with a stirrer. After replacing the gas phase with nitrogen gas, the temperature was raised to 92°C over 40 minutes while stirring. While maintaining the temperature at 92°C, a solution of 16 parts by mass of maleic anhydride and 0.6 parts by mass of t-butyl peroxy-2-ethylhexanoate dissolved in 78 parts by mass of methyl ethyl ketone was continuously added over 5 hours. After the addition was complete, the temperature was raised to 120°C and the reaction was carried out for 1 hour to complete the polymerization. Subsequently, 15 parts by mass of aniline and 0.3 parts by mass of triethylamine were added to the polymerization solution and the reaction was carried out at 140°C for 6 hours. The imidization reaction solution after the reaction was put into a vented screw extruder, and volatile components were removed to obtain pelletized copolymer. The obtained pellets were pulverized using a rotary impeller to obtain powdered copolymer (P-1). As described below 13Compositional analysis of copolymer (P-1) by 13C-NMR revealed that it contained 74.0% by mass of styrene, 23.0% by mass of N-phenylmaleimide, and 3.0% by mass of maleic anhydride. The analytical results of the obtained copolymer (P-1) are shown in Table 1.

[0049] <Composition analysis> The compositional analysis of copolymer (P-1) is as follows: 13 Measurements were taken using the 1C NMR method under the measurement conditions described below. Instrument name: FT-NMR AVANCE300 (manufactured by BRUKER) Solvent: Deuterated chloroform Concentration: 14% by mass Temperature: 27℃ Total number of times: 8000

[0050] <Weight-average molecular weight (Mw) and number-average molecular weight (Mn)> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of copolymer (P-1) are polystyrene-converted values ​​measured by gel permeation chromatography (GPC) under the following conditions. Device name: SYSTEM-21 Shodex (manufactured by Showa Denko Corporation) Column: Three PL gel MIXED-B columns in series Temperature: 40℃ Detection: Differential refractive index Solvent: tetrahydrofuran Concentration: 2% by mass Calibration curve: Created using standard polystyrene (PS) (manufactured by PL Co., Ltd.).

[0051] <Number of unsaturated acid anhydride monomer units per molecular chain of copolymer> The number of unsaturated acid anhydride monomer units (N) per molecular chain of copolymer (P-1) was calculated using the following formula (1) based on the content of unsaturated acid anhydride monomer units in copolymer (P-1) (A, unit: mass%), where the total amount of monomer units contained in copolymer (P-1) is set to 100% by mass, and the number-average molecular weight (Mn) of copolymer (P-1). N=(A / 100)×Mn / 98 Formula (1)

[0052] <Glass transition temperature (Tg)> The glass transition temperature of copolymer (P-1) is the intermediate glass transition temperature (Tmg) measured by DSC in accordance with JIS K-7121, and was measured under the measurement conditions described below. Apparatus name: Robot DSC6200 manufactured by Seiko Instruments Inc. Temperature rising rate: 10 °C / min

[0053] <Solubility in MEK> The solubility of copolymer (P-1) in MEK was evaluated by the weight percentage concentration (wt%) of the MEK solution obtained by dissolving the maximum amount of copolymer (P-1) that could be dissolved in 10 g of MEK at 23 °C. At 23 °C, a predetermined amount of copolymer (P-1) was added to 10 g of MEK in three portions, and the copolymer was dissolved by stirring. At this time, the second addition of copolymer (P-1) was carried out 1 hour after the first addition of copolymer (P-1), and the third addition of copolymer (P-1) was carried out 1 hour after the second addition of copolymer (P-1). After the third addition of copolymer (P-1), it was confirmed that all of the copolymer (P-1) added within 4 hours was completely dissolved. The amount of the predetermined amount of copolymer (P-1) to be dissolved was changed, and the maximum amount of copolymer (P-One) that could be dissolved was determined. The weight percentage concentration (wt%) of the MEK solution when the maximum amount of copolymer (P-1) was dissolved was calculated.

[0054] <Residual styrene monomer content> The residual styrene monomer content in copolymer (P-1) was measured by the following procedure. As a pretreatment, 0.3 to 0.4 g of copolymer (P-1) was weighed into a 50 mL Erlenmeyer flask, 10 mL of DMF containing an internal standard (cyclopentanol) was added to dissolve copolymer (P-1), and the measurement was carried out under the following conditions. Apparatus name: GC-12A (manufactured by Shimadzu Corporation) Detector: FID Column: 3 m glass column (packing: liquid phase PEG20M + TCEP (15 + 5)) Temperature: INJ 150℃, DET 150℃, Column 115℃ Injection volume: 1μL

[0055] <Amount of remaining N-phenylmaleimide monomer> The amount of residual N-phenylmaleimide monomer in copolymer (P-1) was measured under the following conditions. Device name: GC-2010 (manufactured by Shimadzu Corporation) Column: Capillary column DB-5MS (phenylalene polymer) Temperature: Inlet 280°C, Detector 280°C The analysis was performed with a column temperature of 80°C (initial). (Temperature-based analysis conditions) 80℃: Hold for 12 minutes 80-280℃: Heat at a rate of 20℃ / min for 10 minutes 280℃: Hold for 10 minutes Detector: FID Procedure: 0.5 g of copolymer (P-1) was dissolved in 5 ml of 1,2-dichloroethane solution (0.014 g / L) containing undecane (internal standard). Then, 5 ml of n-hexane was added and the mixture was shaken for 10-15 minutes to precipitate. Only the supernatant liquid was injected into a GC after the polymer had precipitated. The quantitative value was calculated from the peak area of ​​the obtained monomer using a coefficient obtained from the internal standard.

[0056] <Thermal stability of copolymers> The 5% mass decrease temperature of copolymer (P-1) by thermogravimetric analysis (TGA) was measured under a nitrogen atmosphere at a heating rate of 5°C / min.

[0057] <Examples 2-24: Synthesis of copolymers (P-2)-(P-24)> Copolymers (P-2) to (P-24) are obtained by adjusting the amount of monomers, polymerization initiator, chain transfer agent, triethylamine, and reaction time as appropriate, using the same procedure as for the synthesis of copolymer (P-1). To synthesize copolymers containing acrylonitrile monomer units, first charge styrene, acrylonitrile, maleic anhydride, α-methylstyrene dimer, and methyl ethyl ketone into an autoclave. Furthermore, for copolymer (P-17), styrene, maleic anhydride, N-phenylmaleimide, α-methylstyrene dimer, and methyl ethyl ketone are first charged into an autoclave. After polymerization is complete, without performing the imidization reaction, the polymerization reaction solution is fed into a vented screw extruder to remove volatile components and obtain a pelletized copolymer. The obtained pellets are then pulverized using a rotary impeller to obtain a powdered copolymer (P-17). Copolymers with relatively low molecular weights are processed by feeding the imidization reaction solution into a vented screw extruder after the reaction is complete, removing volatile components, and then recovering the copolymer without a pelletizing process. The recovered copolymer is then pulverized using a rotary impeller to obtain a powdered copolymer. The composition and properties of copolymers (P-2) to (P-24) are measured using the same method as for copolymer (P-1). The composition and properties of copolymers (P-2) to (P-24) are shown in Tables 1 and 2.

[0058] <Comparative Examples 1-9: Synthesis of Copolymers (PB-1)-(PB-9)> Copolymers (PB-1) to (PB-9) are obtained by adjusting the amount of monomers used, the amount of polymerization initiator, the amount of chain transfer agent, the amount of triethylamine, and the reaction time as appropriate, using the same procedure as for the synthesis of copolymer (P-1). Copolymers with relatively low molecular weights are processed by feeding the imidization reaction solution into a vented screw extruder after the reaction is complete, removing volatile components, and then recovering the copolymer without a pelletizing process. The recovered copolymer is then pulverized using a rotary impeller to obtain a powdered copolymer. The composition and physical properties of copolymers (PB-1) to (PB-9) are measured using the same method as for copolymer (P-1). Table 3 shows the composition and properties of copolymers (PB-1) to (PB-9).

[0059] <Manufacturing of epoxy resin compositions (R-1) to (R-24), (RB-1) to (RB-9)> Each copolymer (P-1) to (P-24), (PB-1) to (PB-9) as a reactive curing agent, 20 g of epoxy resin (product name: EPICLON N-673, manufactured by DIC Corporation), and a styrene-maleic anhydride copolymer (number of maleic anhydride monomer units per molecular chain: 9, glass transition temperature: 120°C, product name: EF40, manufactured by Polyscope Corporation) and a flame retardant (PX-200, Daihachi Chemical Industry Co., Ltd.) are dissolved in 40 g of MEK to obtain epoxy resin compositions (R-1) to (R-24), (RB-1) to (RB-9). Furthermore, the amounts of the copolymer used as a reactive curing agent and the styrene-maleic anhydride copolymer used in combination should be adjusted so that the total amount of the two curing agents is 10 g. Specifically, the amount of copolymer Y (in g) and the amount of styrene-maleic anhydride copolymer Z (in g) should be adjusted as follows, according to the value of the weight percentage concentration X (wt%) of the MEK solution when the maximum amount of copolymer is dissolved, as measured in the evaluation of the copolymer's solubility in MEK. When X(wt%) is 0wt% or greater and less than 50wt% Copolymer content: Y = 2 × X × (10 / 100) Amount of styrene-maleic anhydride copolymer Z = 10 - Y If X(wt%) is 50wt% or more Copolymer blending amount Y=10 Amount of styrene-maleic anhydride copolymer Z=0

[0060] <Properties of epoxy resin compositions> <Heat resistance of epoxy resin composition after curing> The heat resistance of the epoxy resin composition after curing is evaluated by the following method. Sample preparation method: The epoxy resin composition is spread onto a Kapton film, heated and dried at 160°C for 10 minutes, and the solid content is extracted by casting. Next, this solid content is used to create a sample under a pressure of 25 kg / cm². 2 Then, a resin plate is obtained by pressing it at a temperature of 185°C for 90 minutes. • Method for measuring heat resistance: In accordance with JIS C 6481, the glass transition temperature (Tg) is measured by DSC. Here, the glass transition temperature (Tg) is the intermediate glass transition temperature (Tmg), and is the measured value under the measurement conditions described below. Device name: Robot DSC6200 manufactured by Seiko Instruments Inc. Heating rate: 10°C / min • Evaluation criteria A (Excellent): Over 180℃ B (Excellent): Above 175°C, below 180°C C (good): Over 170℃, below 175℃ D (slightly inferior): 160°C or higher, 170°C or lower E (inferior): Below 160℃ The heat resistance of epoxy resin compositions (R-1) to (R-24) and (RB-1) to (RB-9) is shown in Tables 1 to 3.

[0061] <Curability of epoxy resin compositions> The curing properties of the epoxy resin composition are evaluated by the following method. Sample preparation method: The epoxy resin composition is spread onto a Kapton film, heated and dried at 160°C for 10 minutes, and the solid content is extracted by the casting method to obtain the sample before curing. Next, this solid content is used to apply a pressure of 25 kg / cm². 2 Then, the sample is pressed at a temperature of 185°C for 90 minutes to obtain the cured sample. • Method for measuring curability: In accordance with JIS C 6481, the degree of resin curing is calculated by measuring the glass transition temperature (Tg) using the TMA method. Equipment name: Q400, manufactured by T.A. Instruments Japan Co., Ltd. Heating rate: 5°C / min • Evaluation criteria A (Excellent): Hardening degree over 50 B (Excellent): Hardening degree above 40, below 50. C (Good): Curing degree over 30, below 40 D (slightly inferior): Hardening degree 20 or higher, 30 or lower E (Inferior): Hardening degree less than 20 The curability of epoxy resin compositions (R-1) to (R-24), (RB-1) to (RB-9) is shown in Tables 1 to 3.

[0062] <Moisture absorption resistance of the cured product of the epoxy resin composition> The moisture absorption resistance of the cured product of the epoxy resin composition is evaluated by the following method. · Sample preparation method: The epoxy resin composition is spread on a Kapton film and dried by heating at 160 °C for 10 minutes to extract the solid content by the casting method. Next, using this solid content, press at a pressure of 25 kg / cm 2 , at a temperature of 185 °C for 90 minutes to obtain a resin plate. · Measurement method: Measure the water absorption rate in accordance with JIS C 6481 · Evaluation criteria A (Very excellent): Less than 0.5% B (Excellent): 0.5% or more and less than 1.0% C (Good): 1.0% or more and less than 1.5% D (Somewhat inferior): 1.5 or more and 2.0% or less E (Inferior): More than 2.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​In the epoxy resin composition containing the reactive curing agent according to the examples, a copolymer with improved solubility in MEK is used as the reactive curing agent, allowing for a larger amount of copolymer to be incorporated into the epoxy resin composition. As a result, the heat resistance of the epoxy resin composition is improved due to the maleimide monomer units contained in the copolymer.

[0067] Furthermore, even when a styrene-maleic anhydride copolymer is used in combination with the reactive curing agent according to this embodiment as a curing agent for a thermosetting resin, the epoxy resin composition obtained by incorporating the reactive curing agent according to the example exhibits improved heat resistance. In epoxy resin compositions containing a reactive curing agent whose number-average molecular weight of the copolymer is appropriately adjusted, the curability of the epoxy resin composition is improved. Furthermore, in epoxy resin compositions containing a reactive curing agent whose monomer unit composition is appropriately adjusted, by incorporating a larger amount of copolymer into the epoxy resin composition, the amount of styrene-maleic anhydride copolymer, which is another curing agent used in combination, can be reduced, thereby improving the moisture resistance of the cured epoxy resin composition.

[0068] In the comparative example, the reactive curing agent exhibits inferior performance in at least one of the following: solubility in MEK and improvement of the heat resistance of the epoxy resin composition when incorporated into the epoxy resin composition. [Industrial applicability]

[0069] The present invention provides a reactive curing agent that has improved solubility in methyl ethyl ketone (MEK) and can improve the heat resistance of thermosetting resin compositions. By incorporating the reactive curing agent into a thermosetting resin, it can be suitably used in applications requiring heat resistance. Furthermore, the copolymer contained in the reactive curing agent of the present invention is also suitably used as a heat-resistance imparting agent to ABS and other resins, or as a compatibilizer for polymer alloys.

Claims

1. A reactive curing agent comprising a copolymer containing aromatic vinyl monomer units, unsaturated acid anhydride monomer units, and maleimide monomer units, The weight-average molecular weight of the copolymer is 15,000 to 80,000. The copolymer, when the total amount of monomer units contained in the copolymer is 100% by mass, The above maleimide monomer units comprise 3.0 to 30.0% by mass, The aforementioned aromatic vinyl monomer units amount to 45.0 to 96.9% by mass. The aforementioned unsaturated anhydride monomer units amount to 0.1 to 25% by mass, and Other monomer units include 0.0 to 20.0% by mass. Reactive curing agent.

2. The number of unsaturated acid anhydride monomer units contained in each molecular chain of the copolymer is 2 to 25. The reactive curing agent according to claim 1.

3. The glass transition temperature of the copolymer is 125 to 200°C. The reactive curing agent according to claim 1.

4. The weight-average molecular weight of the copolymer is between 20,000 and 70,000. The reactive curing agent according to claim 1.

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