WO2021182360A1

WO2021182360A1 - Maleimide resin and method for producing same, maleimide solution, and curable resin composition and cured product thereof

Info

Publication number: WO2021182360A1
Application number: PCT/JP2021/008836
Authority: WO
Inventors: 窪木　健一; 政隆中西; 一貴松浦
Original assignee: 日本化薬株式会社
Priority date: 2020-03-11
Filing date: 2021-03-05
Publication date: 2021-09-16
Also published as: TW202140607A; JPWO2021182360A1; JP7005821B1; CN115210293A; KR20220152203A

Abstract

Provided is a maleimide resin represented by formula (1). The content of N,N'-(phenylene-di-(2,2-propylidene)-di-phenylene)bismaleimide in the maleimide resin is no more than 98% by area in terms of GPC areal percentage. The content of a maleimide compound represented by formula (2) in the N,N'-(phenylene-di-(2,2-propylidene)-di-phenylene)bismaleimide is at least 30% and less than 60% by area in terms of HPLC areal percentage. (In formula (1), n is the number of repeating units, and the average value thereof is such that 1 < n < 5.)

Description

Maleimide resin and its production method, maleimide solution, and curable resin composition and its cured product

The present invention relates to a maleimide resin and a method for producing the same, a maleimide solution, and a curable resin composition and a cured product thereof. INDUSTRIAL APPLICABILITY The present invention is suitably used for electrical / electronic parts such as semiconductor encapsulants, printed wiring boards, and build-up laminated boards, and lightweight and high-strength materials such as carbon fiber reinforced plastics and glass fiber reinforced plastics.

In recent years, the required characteristics of laminated boards on which electrical and electronic components are mounted have become broader and more sophisticated due to the expansion of their fields of use. For example, conventional semiconductor chips are mainly mounted on metal lead frames, but semiconductor chips with high processing power such as CPUs in recent years may be mounted on laminates made of polymer materials. There are many. As the speed of elements such as CPUs increases and the clock frequency increases, the problems of signal propagation delay and transmission loss are increasing, and the wiring board is required to have a low dielectric constant and a low dielectric loss tangent. In particular, due to the recent increase in the momentum of 5G, electrical characteristics not only in Sub6 but also in quasi-millimeter waves and millimeter waves of 10 GHz or higher, especially 28 GHz or higher, have begun to be emphasized, and materials that can be used stably in these regions are required. Has been done. At the same time, as the speed of the element increases, the heat generated by the chip increases, so that it is necessary to increase the heat resistance.

In addition, with the spread of mobile electronic devices such as mobile phones, precision electronic devices have come to be used and carried in outdoor environments and in the immediate vicinity of the human body, so that they are resistant to the external environment (especially moisture-resistant heat-resistant environment). is required. Furthermore, in the field of automobiles, digitization is progressing rapidly, and precision electronic devices may be placed near the engine, so that heat resistance and moisture resistance are required at a higher level. In addition, since it is used for automobiles and mobile devices, safety such as flame retardancy is becoming more important, but the use of halogen-based flame retardants has been avoided due to the recent increase in awareness of environmental issues. , There is an increasing need to impart flame retardancy without using halogens.

Conventionally, a wiring board using BT resin, which is a resin in which a bisphenol A type cyanate ester compound and a bismaleimide compound are used in combination as in Patent Document 1, is excellent in heat resistance, chemical resistance, electrical characteristics, etc., and is a high-performance wiring. Although it has been widely used as a board, it needs to be improved under the circumstances where higher performance is required as described above.

In recent years, the weight of airplanes, automobiles, trains, ships, etc. has been reduced from the viewpoint of energy saving. In the field of vehicles, studies have been made especially on replacing what used to be a metal material with a lightweight and high-strength carbon fiber composite material. For example, in the Boeing 787, the weight is reduced by increasing the ratio of the composite material, and the fuel efficiency is greatly improved. In the aviation field, there is a movement to introduce carbon fiber composite materials to the members around the engine in order to further reduce the weight, and naturally a high level of heat resistance is required. In the automobile field, it is equipped with a propeller shaft made of composite material, although it is a part, and there is also a movement to make the car body from composite material for luxury cars. In the field of carbon fiber composite materials, composite materials using epoxy resins such as bisphenol A type diglycidyl ether and tetraglycidyl diaminodiphenylmethane and diaminodiphenylmethane and diaminodiphenylsulfone as curing agents have been used. In order to promote weight reduction and high heat resistance, it is necessary to expand the application of composite materials, and maleimide resin is being studied as one means for that purpose.

Under these circumstances, the maleimide compounds or bismaleimide resins available on the market have significantly improved heat resistance as compared with the epoxy resins and the like that have been conventionally used, and there is a strong need to use them for the above-mentioned applications. However, the dielectric properties, especially the dielectric properties in the high frequency region, are not sufficient to meet the needs for high-speed communication. Furthermore, there is a problem that the electrical characteristics are significantly deteriorated by absorbing the moisture in the air, and the applicable range is limited.

On the other hand, maleimide resins have been developed as in Patent Documents 2 and 3, but they are not yet sufficient.

Japanese Patent Publication No. 54-30440 Japanese Patent Application Laid-Open No. 3-100016 Japanese Patent Application Laid-Open No. 2009-1783 Japan Special Fairness No. 4-75222 Gazette Japan Special Fairness No. 6-37465

The present invention contributes to the development of high-speed communication technology typified by 5G by providing a maleimide resin having excellent solvent solubility and excellent electrical characteristics even in a high frequency region.

As a result of diligent research to solve the above problems, the present inventors have completed the present invention.
That is, the present invention relates to the following [1] to [7].
[1]
A maleimide resin represented by the following formula (1).
The content of N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide in the maleimide resin is 98 area% or less in GPC area percentage.
In the N, N'-(phenylene-di- (2,2-propylidene) -di-phenylene) bismaleimide, the content of the maleimide compound represented by the following formula (2) is 30 area% or more in HPLC area percentage. Maleimide resin that is less than 60 area%.

(In equation (1), n is the number of repetitions, and the average value is 1 <n <5.)

[2]
In the N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide, the area ratio (O / P) of ortho-orientation and para-orientation by HPLC area percentage is 100% or more and 200. The maleimide resin according to the preceding item [1], which is less than%.

[3]
In the N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide, the content of the maleimide compound represented by the following formula (3) is less than 50 area% in HPLC area percentage. The maleimide resin according to the preceding item [1] or [2].

[4]
A maleimide solution containing the maleimide resin and an organic solvent according to any one of the above items [1] to [3], wherein the organic solvent is selected from the group consisting of ketones, hydrocarbons, and esters. One or more maleimide solutions.
[5]
A curable resin composition containing the maleimide resin according to any one of the preceding items [1] to [3] or the maleimide solution according to the preceding item [4], and further containing a curing accelerator. Composition.
[6]
A cured product obtained by curing the maleimide resin according to any one of the preceding items [1] to [3] or the curable resin composition according to the preceding item [5].
[7]
To aniline and diisopropenylbenzene or di (α-hydroxyisopropyl) benzene, 1 to 12% by weight of protonic acid is added to the total amount of aniline and reacted at 140 to 190 ° C. to obtain an aromatic amine resin. The method for producing a maleimide resin according to any one of the preceding items [1] to [3], which comprises a step and a step of converting the aromatic amine resin into maleimide.

The maleimide resin of the present invention is not only excellent in solvent solubility, but its cured product is also excellent in electrical properties even in a high frequency region, and is useful for various applications such as electronic materials and structural materials.

It is a graph which shows the change of elastic modulus with temperature in the cured product of Example 15 and Comparative Examples 8-9.

Hereinafter, one embodiment of the present invention will be described in detail.

The maleimide resin of this embodiment is represented by the following formula (1).

(In equation (1), n is the number of repetitions, and the average value is 1 <n <5)

In the formula (1), the value of n can be calculated from the number average molecular weight obtained by the measurement of gel permeation chromatography (GPC, detector: RI) of the maleimide resin, or the area ratio of each of the separated peaks. You can. n is usually 1 <n <5, but more preferably 1 <n <3.
When the average value n is 1, there arises a problem that the solvent solubility is low and crystals are precipitated. On the other hand, when the average value n is 5 or more, the flowability at the time of molding is deteriorated, and there arises a problem that the characteristics as a cured product cannot be exhibited.

GPC analysis (RI) of N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide in the formula (1) in the maleimide resin of the present embodiment. The GPC area percentage is 98 area% or less, preferably 20 to 90 area%, more preferably 30 to 80 area%, still more preferably 40 to 75 area%, and most preferably 40 to 70 area%. Is the range of. When the content of n = 1 body is 98 area% or less, the heat resistance becomes good. In addition, the crystallinity is lowered and the solvent solubility is improved. On the other hand, when the lower limit of n = 1 body is 20 area% or more, the viscosity of the resin solution is lowered and the impregnation property is improved. Further, since the solvent can be removed at a low temperature when it is taken out as a solid, self-polymerization is unlikely to occur and it is easy to handle.

The area% can be measured by GPC (gel permeation chromatography), and in this embodiment, it is measured under the following conditions.
-GPC analysis GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-20A, CBM-20A (all manufactured by Shimadzu Corporation)
Columns: Shodex KF-603, KF-602x2, KF-601x2
Linked eluent: tetrahydrofuran Flow rate: 0.5 ml / min.
Column temperature: 40 ° C
Detection: RI (Differential Refractometer)

The softening point of the maleimide resin of the present embodiment is preferably 50 ° C. to 150 ° C., more preferably 80 ° C. to 120 ° C., further preferably 90 ° C. to 120 ° C., and particularly preferably 95 ° C. to 120 ° C. be. The melt viscosity at 150 ° C. is 0.05 to 100 Pa · s, preferably 0.1 to 40 Pa · s. However, this value may be exceeded by increasing the molecular weight in the polymerization when removing the solvent. The preferable range is an index when the amount of change in area% in GPC of n = 1 when solidified from the state of the solution is 3 area% or less.
The acid value of the maleimide resin of the present embodiment is preferably 30 mgKOH / g, more preferably 1 to 15 mgKOH / g. If the acid value is high, there are many molecules that are not maleimided, and the structure having a carboxylic acid becomes excessive, which affects the electrical properties and water resistance.

The maleimide resin of the present embodiment is a positional isomer as N, N'-(phenylene-di- (2,2-propylidene) -di-phenylene) bismaleimide, which is n = 1 in the above formula (1). It contains a maleimide compound represented by the following formulas (2) to (4).

The content of each of the maleimide compounds represented by the above formulas (2) to (4) in N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide is the HPLC area percentage. The following is preferable.
The maleimide compound represented by the formula (2); 30 area% or more and less than 60 area%, preferably 35 area% or more and less than 55 area%, and more preferably 40 area% or more and less than 55 area%. When the present compound having an asymmetric structure is 30 area% or more, the solvent solubility is improved and the dielectric property is improved. On the other hand, in order to increase the area to 60 area% or more, an additional step such as removing the maleimide compound represented by the above formula (3) by crystallization is required, which causes an increase in manufacturing cost and an increase in industrial waste. Not preferable in terms of points.
The maleimide compound represented by the formula (3); preferably less than 50 area%, more preferably 2 area% or more and less than 35 area%, and preferably 5 area% or more and less than 30 area%. .. When it is less than 50 area%, the solvent solubility is improved and the electrical characteristics are also good.
The maleimide compound represented by the formula (4); preferably 15 area% or more and less than 60 area%, and more preferably 25 area% or more and less than 50 area%. When it is 15 area% or more, the dielectric property is good, and when it is less than 60 area%, the curability and adhesion are good, and defects at the time of producing a substrate or the like can be suppressed.
Since the maleimide compound represented by the above formula (3) has the highest influence on the problem of crystallinity and the problem of deterioration of electrical characteristics, the maleimide compound represented by the formula (2) and the formula (4) are used. The total ratio of the maleimide compounds represented is preferably 50 area% or more, preferably 60 area% or more, in N, N'-(phenylene-di- (2,2-propylidene) -di-phenylene) bismaleimide. Is more preferable, and 70 area% or more is particularly preferable.

Further, in N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide, the area ratio (O / P) of ortho-orientation and para-orientation is 50% or more and less than 300%. It is preferable, and it is more preferable that it is 100% or more and less than 200%.
When the area ratio (O / P) is 50% or more, the solvent solubility and the electrical characteristics are good. Further, if it is less than 300%, problems such as an increase in manufacturing cost and an increase in industrial waste do not occur.
The area ratio (O / P) of ortho-orientation and para-orientation is calculated by the following formula.
Area ratio of ortho-orientation to para-orientation (O / P) = (area% of maleimide compound represented by the above formula (4)) × 2 + (area% of maleimide compound represented by the above formula (2)) / ( Area% of the maleimide compound represented by the formula (3)) × 2 + (Area% of the maleimide compound represented by the formula (2))

The above content can be measured by HPLC (High Performance Liquid Chromatography), and in this embodiment, it is measured under the following conditions.
・ HPLC analysis Liquid transfer unit LC-20AD manufactured by Shimadzu Corporation
Photodiode array detector SPD-M20A manufactured by Shimadzu Corporation
Column oven CTO-20A manufactured by Shimadzu Corporation
Column: Intersil ODS-2.5 μm, 4.6 × 250 mm 40 ° C
MobilePhaseA: Acet Nitrile (AN)
MobilePhaseB: Water (W)
TimeProgram:
0-28 min. AN / W = 30% / 70% → 100% / 0%
28-40 min. AN / W = 100% / 0%
Flow Rate: 1.0 mL / min.
Detection: UV 200-274nm, PDA
Measurement wavelength: 225 nm

The measurement wavelength of HPLC is preferably in the range of 210 to 230 nm. This is because measurement is possible at other wavelengths, but the actual content may differ from the actual content due to the difference in absorption wavelength. The ratio can also be calculated by NMR. When NMR is used, the ratio can be calculated from the peak intensity ratio of the isopropylidene group appearing at 1-2 ppm using ^{13 C-NMR.}

The maleimide resin according to one embodiment of the present invention has high solubility in a solvent and high solubility in other resins, and can be treated as a maleimide solution (hereinafter, also simply referred to as varnish) or a curable resin composition. .. Further, the cured product of the maleimide resin according to the embodiment of the present invention is excellent in electrical characteristics, heat resistance, weather resistance, hygroscopicity, and flame retardancy.

Examples of usable solvents include ketones such as acetone, ethyl methyl ketone and cyclohexanone, hydrocarbons such as benzene, toluene, xylene, tetramethyl benzene and cyclohexane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether and dipropylene glycol. Glycol ethers such as dimethyl ether, dipropylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, ethyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, propylene glycol monomethyl ether acetate , Esters such as dialkyl glutarate, dialkyl succinate, dialkyl adipate, cyclic esters such as γ-butyrolactone, petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrocarbon petroleum naphtha, and solvent naphtha. Among these, ketones, hydrocarbons and esters are preferable, hydrocarbons are more preferable, and aromatic hydrocarbons are particularly preferable. These may be used alone or in combination of two or more. The solvent is used in a range in which the solid content concentration of the obtained varnish excluding the solvent is usually 10 to 80% by weight, preferably 20 to 70% by weight.
A maleimide solution can be obtained by dissolving the maleimide resin in a solvent, but it is preferable to provide the solvent used at the time of synthesis as the maleimide solution as it is. This is because industrial waste and energy consumption are reduced.

Next, the method for producing the maleimide resin of the present embodiment will be described, but the method is not limited to this method.

[Manufacturing method of aromatic amine resin]
As the maleimide resin of the present embodiment, an aromatic amine resin represented by the following formula (5) can be used as a precursor.

(In equation (5), n is the number of repetitions, and the average value is 1 <n <5.)

The production method of the aromatic amine resin represented by the above formula (5) is not particularly limited. For example, in Patent Document 4, aniline and m-diisopropenylbenzene or m-di (α-hydroxyisopropyl) benzene are reacted at 180 to 250 ° C. in the presence of an acidic catalyst to form the formula (5). It is disclosed that n = 1 body is obtained as a main component. Among these n = 1 bodies are 1- (o-aminocumyl) -3- (p-aminocumyl) benzene represented by the following formula (6) and 1,3-bis represented by the following formula (7). It contains three isomers of (p-aminocumyl) benzene and 1,3-bis (o-aminocumyl) benzene represented by the following formula (8).

In Patent Document 4, further n = 2 to 5 bodies contained as subcomponents are purified by crystallization to obtain 1,3-bis (p-aminocumyl) benzene having a purity of 98%. Further, in Patent Document 5, 1,3-bis (p-aminocumyl) benzene is maleiminated to form N, N'-(1,3-phenylene-di- (2,2-propanol) -di-p-phenylene). Benzeneimide is synthesized to obtain a crystal product, but heating is required to dissolve it in a solvent, and if it is left at room temperature after heating, crystals will precipitate within a few hours. Therefore, crystals may precipitate even when the resin composition is adjusted, and N, N'-(1,3-phenylene-di- (2,2-propanol) -di-p-phenylene) bismaleimide The higher the concentration, the higher the possibility of crystallization. In order to manufacture printed wiring boards and composite materials, varnish is impregnated with glass cloth or carbon fiber to attach resin, but if crystals are precipitated, impregnation work becomes impossible, while in order to maintain the dissolved state. Increasing the temperature accelerates the reaction of the composition and shortens the pot life of the varnish.

In the production method according to one embodiment of the present invention, a maleimide resin is synthesized using an amine resin having a molecular weight distribution and containing an asymmetric amine to improve solvent solubility and dielectric properties in a cured product thereof. be able to.
Among the aromatic amine resins represented by the formula (5), the aromatic amine compound represented by the formula (6) is preferably 30 area% or more and less than 60 area% in terms of HPLC area percentage, preferably 30 area. It is more preferably% or more and less than 55 area%, and particularly preferably 35 area% or more and less than 50 area%.

When synthesizing the aromatic amine resin represented by the formula (5), the acidic catalysts used are hydrochloric acid, phosphoric acid, sulfuric acid, formic acid, zinc chloride, ferric chloride, aluminum chloride, p-toluenesulfonic acid, and methane. Examples thereof include acidic catalysts such as sulfonic acid. In this embodiment, protonic acids such as hydrochloric acid, p-toluenesulfonic acid and methanesulfonic acid are preferable. These may be used alone or in combination of two or more. The amount of the catalyst used is usually 1 to 30% by weight, preferably 1 to 17% by weight, more preferably 1 to 12% by weight, particularly preferably 1 to 7% by weight, based on the aniline used. If it is too much, the target compound having an asymmetric structure is few, and the compound having a symmetrical structure is preferentially formed. If the amount is too small, not only the progress of the reaction will be slowed down, but also the reaction may not be completed, which is not preferable.

If necessary, the reaction may be carried out using an organic solvent such as toluene or xylene, or may be carried out without a solvent. For example, after adding an acidic catalyst to a mixed solution of aniline and a solvent, if the catalyst contains water, it is preferable to remove the water from the system by azeotropic boiling. After that, diisopropenylbenzene or di (α-hydroxyisopropyl) benzene is added, and then the temperature is raised while removing the solvent from the system to 140 to 190 ° C., preferably 160 to 190 ° C. for 5 to 50 hours, preferably. The reaction is carried out for 5 to 30 hours. If the reaction temperature is too high, the asymmetric structure will be recombined after formation, and the symmetric structure will be formed preferentially, so that the desired solvent solubility and electrical characteristics cannot be exhibited. Since water is produced as a by-product when di (α-hydroxyisopropyl) benzene is used, it is removed from the system while being azeotropically heated with a solvent when the temperature is raised. After completion of the reaction, the acidic catalyst is neutralized with an alkaline aqueous solution, a water-insoluble organic solvent is added to the oil layer, and washing is repeated until the wastewater becomes neutral, and then the solvent and excess aniline derivative are removed under heating and reduced pressure. .. When activated clay or an ion exchange resin is used, the reaction solution is filtered after the reaction is completed to remove the catalyst.
Further, since diphenylamine is by-produced depending on the reaction temperature and the type of catalyst, it is preferable to remove it if necessary. The diphenylamine derivative is removed to 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.2% by weight or less under high temperature and high vacuum or by means such as steam distillation.

The maleimide resin of the present embodiment contains, for example, an aromatic amine resin represented by the above formula (5), maleic acid or maleic anhydride (hereinafter, also referred to as "maleic anhydride") as a solvent and a catalyst. It is obtained by adding or dehydrating and condensing underneath.

[Manufacturing method of maleimide resin]
As the solvent used in the reaction, it is necessary to remove the water generated during the reaction from the system, so a water-insoluble solvent is used. For example, aromatic solvents such as toluene and xylene, aliphatic solvents such as cyclohexane and n-hexane, ethers such as diethyl ether and diisopropyl ether, ester solvents such as ethyl acetate and butyl acetate, methyl isobutyl ketone, cyclopentanone and the like. The above-mentioned ketone solvent and the like can be mentioned, but the present invention is not limited to these, and two or more kinds may be used in combination.

Further, in addition to the water-insoluble solvent, an aprotic polar solvent can be used in combination. For example, dimethyl sulfone, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone and the like can be mentioned, and two or more of them may be used in combination. When an aprotic polar solvent is used, it is preferable to use a solvent having a boiling point higher than that of the water-insoluble solvent used in combination.

The catalyst used in the reaction is an acidic catalyst, and is not particularly limited, and examples thereof include p-toluenesulfonic acid, hydroxy-p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, and phosphoric acid. The amount of the acidic catalyst used is usually 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the aromatic amine resin. If there are many acid catalysts, the para-orientation becomes strong, which may adversely affect the crystallinity and dielectric properties.

For example, an aromatic amine resin represented by the above formula (5) is dissolved in toluene and N-methyl-2-pyrrolidone, and maleic anhydride is added thereto to produce an amic acid, and then p-toluenesulfon. The reaction is carried out by adding an acid and removing the water produced under reflux conditions from the system.

Alternatively, maleic anhydride is dissolved in toluene, and an N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by the above formula (5) is added under stirring to produce an amic acid, and then p-. The reaction is carried out while adding toluenesulfonic acid and removing the water produced under reflux conditions from the system.

Alternatively, maleic anhydride is dissolved in toluene, p-toluenesulfonic acid is added, and an N-methyl-2-pyrrolidone solution of the aromatic amine resin represented by the above formula (5) is added dropwise in a stirred / refluxed state. However, the water that azeotropes on the way is removed to the outside of the system, and the toluene is returned to the inside of the system to carry out the reaction (the above is the first stage reaction).

In either method, maleic anhydride is usually used in an amount of 1 to 3 times, preferably 1.2 to 2.0 times the equivalent of the amino group of the aromatic amine resin represented by the formula (5). do.

In order to reduce the amount of unclosed ring amic acid, water is added to the reaction solution after the maleimization reaction listed above to separate the resin solution layer and the aqueous layer, and excess maleic acid, maleic anhydride, and aprotic polarity. Since the solvent, catalyst, etc. are dissolved on the aqueous layer side, separate and remove them, and repeat the same operation to thoroughly remove excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst. .. The catalyst is added again to the maleimide resin solution of the organic layer from which excess maleic acid, maleic anhydride, aprotic polar solvent, and catalyst have been removed, and the dehydration ring closure reaction of the residual amic acid under heating / reflux conditions is performed again. It does not matter (the above is the second stage reaction). By performing this method, a maleimide resin solution having a low acid value can be obtained, but in the present embodiment, only the first-stage reaction may be used.

The time of the re-dehydration ring closure reaction is usually 1 to 5 hours, preferably 1 to 3 hours, and the above-mentioned aprotic polar solvent may be added if necessary. After completion of the reaction, the mixture is cooled and washed with water until the water is neutral. Then, after removing water by azeotropic dehydration under heating and reduced pressure, the solvent may be distilled off or another solvent may be added to adjust the resin solution to a desired concentration, or the solvent may be completely retained. It may be removed and taken out as a solid resin.

Next, the curable resin composition of the present embodiment will be described.
The curable resin composition of the present embodiment may contain a compound capable of cross-linking with the maleimide resin of the present embodiment. Examples of the compound include functional groups (or functional groups) capable of cross-linking with a maleimide resin such as an amino group, a cyanate group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an allyl group, a metallicyl group, an acrylic group, a methacryl group, a vinyl group and a conjugated diene group. The amine compound and the maleimide compound are not particularly limited as long as they have a structure), and therefore, an aromatic amine resin represented by the above formula (5) may be used. Since the maleimide resin can be self-polymerized, it can be used alone. Further, an amine compound other than the aromatic amine resin represented by the formula (5) or a maleimide compound other than the maleimide resin represented by the formula (1) may be used in combination.

The content of the maleimide resin represented by the formula (1) in the curable resin composition of the present embodiment is preferably 10% by weight or more, more preferably 15% by weight or more, still more preferably 20% by weight. %. In the above range, the physical properties of the cured product tend to be high in mechanical strength, high in peel strength, and high in heat resistance.

As the amine compound that can be blended in the curable resin composition of the present embodiment, a conventionally known amine compound can be used. Specific examples of amine compounds include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylaminopropylamine, isophoronediamine, and 1,3-bisaminomethyl. Cyclohexane, bis (4-aminocyclohexyl) methane, bis (4-amino-3-methylcyclohexyl) methane, norbornene diamine, 1,2-diaminocyclohexane, diaminodiphenylmethane, metaphenylenediamine, diaminodiphenylsulfone, dicyandiamide, polyoxypropylene Examples thereof include, but are not limited to, diamines, polyoxypropylene triamines, N-aminoethylpiperazines, and aniline / formalin resins. These may be used alone or in combination of two or more.
Further, the aromatic amine resin described in the claims of Patent Document 3 is particularly preferable because it is excellent in low hygroscopicity, flame retardancy, and dielectric properties.

As the maleimide compound that can be blended in the curable resin composition of the embodiment, a conventionally known maleimide compound can be used. Specific examples of the maleimide compound include 4,4'-diphenylmethanebismaleimide, polyphenylmethanemaleimide, m-phenylenebismaleimide, 2,2'-bis [4- (4-maleimidephenoxy) phenyl] propane, 3,3. '-Dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylene bismaleimide, 4,4'-diphenylether bismaleimide, 4,4'-diphenylsulphon bismaleimide , 1,3-Bis (3-maleimidephenoxy) benzene, 1,3-bis (4-maleimidephenoxy) benzene and the like, but are not limited thereto. These may be used alone or in combination of two or more. The blending amount of the maleimide compound is preferably in the range of 5 times or less, more preferably 2 times or less of the maleimide resin of the present embodiment in terms of weight ratio.
Further, the maleimide resin described in claim 3 of Patent Document 3 is particularly preferable because it is excellent in low hygroscopicity, flame retardancy, and dielectric properties.

As the cyanate ester compound that can be blended in the curable resin composition of the present embodiment, a conventionally known cyanate ester compound can be used. Specific examples of cyanate ester compounds include polycondensates of phenols and various aldehydes, polymers of phenols and various diene compounds, polycondensations of phenols and ketones, and polycondensations of bisphenols and various aldehydes. Examples thereof include cyanate ester compounds obtained by reacting a substance with cyanide halide, but the present invention is not limited thereto. These may be used alone or in combination of two or more.
Examples of the phenols include phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl-substituted dihydroxybenzene, and dihydroxynaphthalene.
Examples of the various aldehydes include formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl-substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaraldehyde, phthalaldehyde, crotonaldehyde, and cinnamaldehyde.
Examples of the various diene compounds include dicyclopentadiene, terpenes, vinylcyclohexene, norbornadiene, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, and isoprene.
Examples of the ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone and the like.
Further, the cyanate ester compound whose synthesis method is described in Japanese Patent Application Laid-Open No. 2005-264154 is particularly preferable as the cyanate ester compound because it is excellent in low hygroscopicity, flame retardancy and dielectric properties.

In the curable resin composition of the present embodiment, an epoxy resin can be further blended. As the epoxy resin that can be blended, any conventionally known epoxy resin can be used. Specific examples of epoxy resins include polycondensates of phenols and various aldehydes, polymers of phenols and various diene compounds, polycondensations of phenols and ketones, and polycondensates of bisphenols and various aldehydes. Alicyclic epoxies typified by glycidyl ether-based epoxy resins obtained by glycidylizing alcohols, 4-vinyl-1-cyclohexene epoxides, 3,4-epoxycyclohexylmethyl-3,4'-epoxycyclohexanecarboxylate, etc. Examples thereof include, but are not limited to, resins, glycidylamine-based epoxy resins typified by tetraglycidyldiaminodiphenylmethane (TGDDM) and triglycidyl-p-aminophenol, and glycidyl ester-based epoxy resins. These may be used alone or in combination of two or more.
Further, the epoxy resin obtained by subjecting a phenol aralkyl resin obtained by a condensation reaction of phenols with a bishalogenomethyl aralkyl derivative or an aralkyl alcohol derivative as a raw material and reacting with epichlorohydrin by dehydroxylation is a low moisture absorption and flame retardant. It is particularly preferable as an epoxy resin because it has excellent properties and dielectric properties.

When the epoxy resin is blended, the blending amount is not particularly limited, but is preferably 0.1 to 10 times, more preferably 0.2 to 4 times, the weight ratio of the maleimide resin. If the blending amount of the epoxy resin is 0.1 times or less of that of the maleimide resin, the cured product may become brittle, and if it is 10 times or more, the dielectric properties may deteriorate.

In the curable resin composition of the present embodiment, a compound having a phenol resin can be further blended.
As the phenol resin that can be blended, any conventionally known phenol resin can be used. Specific examples of phenolic resins include bisphenols (bisphenol A, bisphenol F, bisphenol S, biphenol, bisphenol AD, etc.) and phenols (phenol, alkyl-substituted phenol, aromatic-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, alkyl. Polycondensate of substituted dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes (formaldehyde, acetaldehyde, alkylaldehyde, benzaldehyde, alkyl substituted benzaldehyde, hydroxybenzaldehyde, naphthaldehyde, glutaaldehyde, phthalaldehyde, crotonaldehyde, cinnamaldehyde, etc.), Polymers of phenols and various diene compounds (dicyclopentadiene, terpenes, vinylcyclohexene, norbornadien, vinylnorbornene, tetrahydroindene, divinylbenzene, divinylbiphenyl, diisopropenylbiphenyl, butadiene, isoprene, etc.), phenols and ketones. Polycondensates with species (acetones, methylethylketones, methylisobutylketones, acetophenones, benzophenones, etc.), phenols and aromatic dimethanols (benzenedimethanol, α, α, α', α'-benzenedimethanol, biphenyldi. Polycondensation with methanol, α, α, α', α'-biphenyldimethanol, etc., and polycondensation of phenols with aromatic dichloromethyls (α, α'-dichloroxylene, bischloromethylbiphenyl, etc.) Examples include, but are not limited to, bisphenols and polycondensates of various aldehydes, and modified products thereof. These may be used alone or in combination of two or more.
Further, the phenol aralkyl resin obtained by subjecting phenols to the above-mentioned bishalogenomethyl aralkyl derivative or aralkyl alcohol derivative in a condensation reaction is particularly preferable as a phenol resin because it is excellent in low moisture absorption, flame retardancy and dielectric properties. ..
Further, when the above-mentioned phenol resin has an allyl group or a metalyl group, the reactivity with the maleimide group is better than that of the hydroxyl group, so that the curing rate is increased and the cross-linking points are increased, so that the strength and heat resistance are increased. Therefore, it is preferable.
Further, an allyl ether body obtained by allylating the hydroxyl group of the phenol resin or a metalyl ether body obtained by metallizing the hydroxyl group can also be blended, and the water absorption is lowered because the hydroxyl group is etherified.

In the curable resin composition of the present embodiment, a compound having an acid anhydride group can be further blended.
As the compound having an acid anhydride group that can be blended, any conventionally known compound can be used. Specific examples of the compound having an acid anhydride group include 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3. 4-Cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, pyromellitic acid anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl- 3-Cyclohexene-1,2-dicarboxylic acid anhydride, 4- (2,5-dioxo tetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid anhydride, etc. Can be mentioned.
Compounds having an acid anhydride group can be used alone or in admixture of two or more. Further, as a result of the reaction between the acid anhydride group and the amine, it becomes an amic acid, but when it is further heated at 200 ° C. to 300 ° C., it becomes an imide structure by a dehydration reaction, and becomes a material having excellent heat resistance.

A catalyst for curing (curing accelerator) can be added to the curable resin composition of the present embodiment, if necessary. For example, imidazoles such as 2-methylimidazole, 2-ethyl imidazole, 2-phenyl imidazole, 2-ethyl-4-methyl imidazole, 2-undecyl imidazole, 1-cyanoethyl-2-ethyl-4-methyl imidazole, triethylamine, Amines such as triethylenediamine, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo (5,4,0) undecene-7, tris (dimethylaminomethyl) phenol, benzyldimethylamine, triphenylphosphine, Hosphins such as tributylphosphine and trioctylphosphine, organic metal salts such as tin octylate, zinc octylate, dibutyltin dimaleate, zinc naphthenate, cobalt naphthenate, tin oleate, zinc chloride, aluminum chloride, tin chloride, etc. Metal chlorides, organic peroxides such as di-tert-butyl peroxide and dicumyl peroxide, azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile, ores such as hydrochloric acid, sulfuric acid and phosphoric acid. Examples thereof include acids, Lewis acids such as boron trifluoride, and salts such as sodium carbonate and lithium chloride. In particular, in the present embodiment, the above-mentioned amines, phosphines, and further organic peroxides are preferably blended. The blending amount of the curing catalyst is preferably in the range of 10 parts by weight or less, more preferably 5 parts by weight or less, based on 100 parts by weight of the total of the curable resin composition.

In the present embodiment, particularly from the viewpoint of dielectric properties, it is preferable to blend polybutadiene and a modified product thereof, a curable polymer such as a styrene butadiene copolymer, and further substituted or unsubstituted polyphenylene ether, polystyrene, and a fluororesin. In particular, as a functional group, those having a structure such as 1,2-vinyl group, acrylic group, methacrylic group, allyl group, metallicl group, vinylbenzene and inden in the molecule are preferable. In particular, a combination with a styrene-butadiene copolymer having a 1,2 vinyl group, acrylic, a polyphenylene ether having a methacryl group, or the like is preferable from the viewpoints of dielectric properties, film properties, and the like.

Further, a known additive can be added to the curable resin composition of the present embodiment, if necessary. Specific examples of the additives that can be used include curing agents for epoxy resins, modified products of acrylonitrile copolymers, polyethylene, polyimides, maleimide compounds, maleimide resins, cyanate ester compounds, cyanate ester resins, silicone gels, silicone oils, and the like. In addition, inorganic fillers such as silica, alumina, calcium carbonate, quartz powder, aluminum powder, graphite, talc, clay, iron oxide, titanium oxide, aluminum nitride, asbestos, mica, glass powder, and fillers such as silane coupling agents. Examples thereof include surface treatment agents, mold release agents, and colorants such as carbon black, phthalocyanine blue, and phthalocyanine green. The blending amount of these additives is preferably in the range of 1,000 parts by weight or less, more preferably 700 parts by weight or less, based on 100 parts by weight of the curable resin composition.

The method for preparing the curable resin composition of the present embodiment is not particularly limited, but each component may be uniformly mixed or prepolymerized. For example, the maleimide resin and the cyanate ester compound are prepolymerized by heating in the presence or absence of a catalyst and in the presence or absence of a solvent. Similarly, the maleimide resin of the present embodiment and, if necessary, an epoxy resin, an amine compound, a maleimide compound, a cyanate ester compound, a phenol resin, an acid anhydride compound and other additives may be added to prepolymerize. For mixing or prepolymerizing each component, for example, an extruder, kneader, roll or the like is used in the absence of a solvent, and a reaction kettle with a stirrer is used in the presence of a solvent.

A prepreg can be obtained by heating and melting the curable resin composition of the present embodiment, lowering the viscosity, and impregnating reinforcing fibers such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, and alumina fiber. A prepreg can also be obtained by impregnating the fibers as described above with the varnish and heating and drying the varnish. As the fiber to be used, it is preferable to use not only E glass but also low dielectric glass such as NE glass, glass fiber using quartz glass and the like, especially in high frequency applications. The blending amount of these fibers is preferably 10% by volume to 70% by volume, particularly preferably 20% by volume to 65% by volume, based on 100% by volume of the total amount of the resin. It can also be handled in combination with a filler or the like, in which case the total amount of fibers and filler is preferably 80% by volume or less with respect to 100% by volume of the total amount of resin. If it exceeds 80% by volume, not only the sheet becomes brittle, but also the flowability at the time of curing later is not obtained, which makes it difficult to handle as a substrate.
The above prepreg is cut into a desired shape, laminated with copper foil or the like if necessary, and then the curable resin composition is heat-cured while applying pressure to the laminate by a press molding method, an autoclave molding method, a sheet winding molding method, or the like. Thereby, a laminated board for electric and electronic (printed wiring board) and a carbon fiber reinforcing material can be obtained.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples. In the text, "parts" and "%" represent "parts by weight" and "% by weight", respectively. The softening point and the melt viscosity were measured by the following methods.
Softening point: Measured according to JIS K-7234 Acid value: Measured according to JIS K-0070: 1992

-GPC (Gel Permeation Chromatography) Analysis GPC: DGU-20A3R, LC-20AD, SIL-20AHT, RID-20A, SPD-20A, CTO-20A, CBM-20A (all manufactured by Shimadzu Corporation)
Columns: Shodex KF-603, KF-602x2, KF-601x2
Linked eluent: tetrahydrofuran Flow rate: 0.5 ml / min.
Column temperature: 40 ° C
Detection: RI (Differential Refractometer)

-Calculated from the area% of maleimide equivalent GPC.

・ HPLC (High Performance Liquid Chromatography) Analysis Liquid Feeding Unit LC-20AD manufactured by Shimadzu Corporation
Photodiode array detector SPD-M20A manufactured by Shimadzu Corporation
Column oven CTO-20A manufactured by Shimadzu Corporation
Column: Intersil ODS-2.5 μm, 4.6 × 250 mm 40 ° C
MobilePhaseA: Acet Nitrile (AN)
MobilePhaseB: Water (W)
TimeProgram:
0-28 min. AN / W = 30% / 70% → 100% / 0%
28-40 min. AN / W = 100% / 0%
Flow Rate: 1.0 mL / min.
Detection: UV 200-274nm, PDA
Measurement wavelength: 225 nm

[Synthesis Example 1]
In a flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer, 373 parts of aniline, 150 parts of toluene, 194 parts of m-di (α-hydroxyisopropyl) benzene, and activated clay (E made in Japan) 75 parts were charged, the temperature inside the system was raised to 170 ° C. over 6 hours while distilling off water and toluene, and the reaction was carried out at this temperature for 20 hours. Then, the mixture was cooled to room temperature, 600 parts of toluene was added, and activated clay was removed by filtration. Next, 320 parts of the aromatic amine resin (SA-1) represented by the above formula (5) was obtained by distilling off excess aniline and toluene from the oil layer under heating and reduced pressure with a rotary evaporator. The amine equivalent of the aromatic amine resin (SA-1) was 180.5 g / eq, and the softening point was 45 ° C. According to GPC analysis (RI), n = 1 body was 78.8 area%, and the average n was 1.22. The ratio of isomers in n = 1 body by HPLC analysis is shown in Table 1. The area ratio (o / p) of the ortho-orientation and the para-orientation was 28%.
Area ratio (O / P) by HPLC analysis of ortho-orientation and para-orientation = (area% of aromatic amine compound represented by the above formula (7)) × 2 + (aromatic amine represented by the above formula (6)) Compound area%) / (Aromatic amine compound area% represented by the formula (8)) x 2+ (Aromatic amine compound area% represented by the formula (6))

[Synthesis Example 2]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 804 parts of aniline, 432 parts of toluene, and 450 parts of 35% hydrochloric acid, and water and toluene were distilled off while raising the temperature. The temperature was set to 170 ° C., and 158 parts of 1,3-diisopropenylbenzene was added dropwise at this temperature over 1.5 hours, and the reaction was carried out at the same temperature for 30 hours. Then, while cooling, 87 parts of a 30% sodium hydroxide aqueous solution was slowly added dropwise so that the inside of the system did not reflux violently, 432 parts of toluene was added at 80 ° C. or lower, and the mixture was allowed to stand at 70 ° C. to 80 ° C. The separated lower aqueous layer was removed, and washing of the reaction solution with water was repeated until the washing solution became neutral. Next, excess aniline and toluene were distilled off from the oil layer with a rotary evaporator under heating and reduced pressure, 864 parts of toluene was added to dissolve the mixture, and 864 parts of cyclohexane was added to perform crystallization, filtration, and drying. 303 parts of the aromatic amine resin (SA-2) represented by (5) was obtained. According to GPC analysis (RI), n = 98% or more per body, and the average n was 1. The ratio of isomers in n = 1 body by HPLC analysis is shown in Table 1. The area ratio (o / p) of the ortho-orientation and the para-orientation was 0%.

[Synthesis Example 3]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 373 parts of aniline, 250 parts of toluene, and 10 parts of 35% hydrochloric acid, and water and toluene were distilled off while raising the temperature. The temperature was set to 170 ° C., and 194 parts of 1,3-diisopropenylbenzene was added dropwise at this temperature over 1.5 hours, and the reaction was carried out at the same temperature for 45 hours. Then, while cooling, 17.4 parts of a 30% sodium hydroxide aqueous solution was slowly added dropwise so that the inside of the system did not reflux violently, 300 parts of toluene was added at 80 ° C. or lower, and the mixture was allowed to stand at 70 ° C. to 80 ° C. The separated lower aqueous layer was removed, and washing of the reaction solution with water was repeated until the washing solution became neutral. Then, excess aniline and toluene were distilled off from the oil layer under heating and reduced pressure with a rotary evaporator to obtain 306 parts of the aromatic amine resin (A-1) represented by the above formula (5). The amine equivalent of the aromatic amine resin (A-1) was 187.9 g / eq, and the softening point was 59 ° C. According to GPC analysis (RI), n = 1 body was 62.5 area%, and the average n was 1.45. The ratio of isomers in n = 1 body by HPLC analysis is shown in Table 1. The area ratio (o / p) of the ortho-orientation and the para-orientation was 176%.

[Synthesis Examples 4 to 12]
In Synthesis Example 3, the catalyst used, the amount of catalyst, the amount of aniline, the reaction temperature, and the reaction time were changed, and amine resins A-2 to A-10 were synthesized. The results are shown in Table 1.

[Synthesis Example 13]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 192 parts of aniline, 123 parts of toluene, and 194 parts of 1,3-diisopropenylbenzene, and 21 parts of 35% hydrochloric acid while stirring. Was prepared. Then, while raising the temperature, water and toluene were distilled off to bring the temperature inside the system to 160 ° C., and the reaction was carried out for 24 hours. Then, while cooling, 30 parts of a 30% sodium hydroxide aqueous solution was slowly added dropwise so that the inside of the system did not reflux violently, 20 parts of toluene was added at 80 ° C. or lower, and the mixture was allowed to stand at 70 ° C. to 80 ° C. The separated lower aqueous layer was removed, and washing of the reaction solution with water was repeated until the washing solution became neutral. Next, excess aniline and toluene are distilled off from the oil layer under heating and reduced pressure with a rotary evaporator, and then excess aniline and toluene are distilled off from the oil layer under heating and reducing pressure with a rotary evaporator, thereby being represented by the above formula (5). 158 parts of the aromatic amine resin (A-11) was obtained. The amine equivalent of the aromatic amine resin (A-13) was 186 g / eq, and the softening point was 58.8 ° C. According to GPC analysis (RI), n = 1 body is 64.9 area%, and the ratio of isomers in n = 1 body by HPLC analysis is shown in Table 1.

HCl: 35% aqueous hydrochloric acid solution (manufactured by Junsei Chemical Co., Ltd.)

[Comparative Example 1]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 4 parts of methanesulfonic acid, and brought into a heated reflux state. Next, a resin solution prepared by dissolving 197 parts of an aromatic amine resin (SA-1) in 95 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added dropwise over 3 hours while maintaining a reflux state. During this period, the condensed water and toluene that azeotrope under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, then the organic layer toluene was returned to the inside of the system, and the water was discharged to the outside of the system. After the completion of dropping the resin solution, the reaction was carried out for 6 hours while maintaining a reflux state and performing a dehydration operation. After completion of the reaction, washing with water was repeated 4 times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotrope of toluene and water under heating and reduced pressure of 70 ° C. or lower. Next, 2 parts of methanesulfonic acid was added, and the reaction was carried out in a heated reflux state for 2 hours. After completion of the reaction, water washing was repeated 4 times until the water was neutralized, and then water was removed from the system by azeotropic boiling of ruen and water under heating and reduced pressure of 70 ° C. or lower, and toluene was heated and reduced under reduced pressure. By completely distilling off, a maleimide resin (SM-1) represented by the above formula (1) was obtained. The obtained maleimide resin (SM-1) had a softening point of 100 ° C. and an acid value of 9 mgKOH / g. According to GPC analysis (RI), n = 1 body was 73%, and the average n was 1.37. The ratio of isomers in n = 1 by HPLC analysis is shown in Table 2. The area ratio (o / p) of the ortho-orientation and the para-orientation was 30%.

[Comparative Example 2]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 3.3 parts of methanesulfonic acid, and brought into a heated reflux state. Next, a resin solution prepared by dissolving 172 parts of 1,3-bis (p-aminocumyl) benzene (SA-2) in 66 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added over 3 hours while maintaining the reflux state. And dropped. During this period, the condensed water and toluene that azeotrope under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, then the organic layer toluene was returned to the inside of the system, and the water was discharged to the outside of the system. After the completion of dropping the resin solution, the reaction was carried out for 2 hours while maintaining a reflux state and performing a dehydration operation. After completion of the reaction, washing with water was repeated 4 times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotrope of toluene and water under heating and reduced pressure of 70 ° C. or lower. Next, 1.7 parts of methanesulfonic acid was added, and the reaction was carried out in a heated reflux state for 2 hours. After completion of the reaction, water washing was repeated 3 times until the water was neutralized, and then water was removed from the system by azeotropic boiling of ruen and water under heating and reduced pressure of 70 ° C. or lower, and then toluene was heated and reduced under reduced pressure. 237 parts of maleimide resin (SM-2) was obtained by completely distilling off the mixture. The obtained maleimide resin (SM-2) had a softening point of 91 ° C. and an acid value of 3 mgKOH / g. By GPC analysis (RI), n = 1 body was 95%, and the average n was 1.02. The ratio of isomers in n = 1 is shown in Table 2. The area ratio (o / p) of the ortho-orientation and the para-orientation was 0%.

[Example 1]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 4 parts of methanesulfonic acid, and brought into a heated reflux state. Next, a resin solution prepared by dissolving 197 parts of the aromatic amine resin (A-1) in 95 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added dropwise over 3 hours while maintaining a reflux state. During this period, the condensed water and toluene that azeotrope under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, then the organic layer toluene was returned to the inside of the system, and the water was discharged to the outside of the system. After the completion of dropping the resin solution, the reaction was carried out for 6 hours while maintaining a reflux state and performing a dehydration operation. After completion of the reaction, washing with water was repeated 4 times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotrope of toluene and water under heating and reduced pressure of 70 ° C. or lower. Next, 2 parts of methanesulfonic acid was added, and the reaction was carried out in a heated reflux state for 2 hours. After completion of the reaction, water washing was repeated 4 times until the water was neutralized, and then water was removed from the system by azeotropic distillation of toluene and water under heating and reduced pressure of 70 ° C. or lower, and then toluene was heated and reduced under reduced pressure. After distilling off the solvent until the resin concentration reached about 70-80%, toluene was added to adjust the resin concentration to 60%. As a result, a maleimide solution (V1) containing a maleimide resin (M-1) was obtained. According to GPC analysis (RI), n = 1 body was 57%, and the average n was 1.80. The ratio of isomers in n = 1 by HPLC analysis is shown in Table 2. A maleimide resin (M-1) represented by the above formula (1) was obtained by completely distilling off the solvent in 50 parts of the obtained resin solution, especially under heating and reduced pressure. The obtained maleimide resin (M-1) had a softening point of 115 ° C. and an acid value of 7.5 mgKOH / g. The area ratio (o / p) of the ortho-orientation and the para-orientation was 163%.

[Example 2]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 4 parts of methanesulfonic acid, and brought into a heated reflux state. Next, a resin solution prepared by dissolving 197 parts of the aromatic amine resin (A-2) in 95 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added dropwise over 3 hours while maintaining a reflux state. During this period, the condensed water and toluene that azeotrope under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, then the organic layer toluene was returned to the inside of the system, and the water was discharged to the outside of the system. After the completion of dropping the resin solution, the reaction was carried out for 6 hours while maintaining a reflux state and performing a dehydration operation. After completion of the reaction, washing with water was repeated 4 times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotrope of toluene and water under heating and reduced pressure of 70 ° C. or lower. Next, 2 parts of methanesulfonic acid was added, and the reaction was carried out in a heated reflux state for 2 hours. After completion of the reaction, water washing was repeated 4 times until the water was neutralized, and then water was removed from the system by azeotropic boiling of ruen and water under heating and reduced pressure of 70 ° C. or lower, and then toluene was heated and reduced under reduced pressure. The maleimide resin (M-2) represented by the above formula (1) was obtained by completely distilling off the mixture. The obtained maleimide resin (M-2) had a softening point of 111 ° C. and an acid value of 8 mgKOH / g. According to GPC analysis (RI), n = 1 body was 56%, and the average n was 1.78. The ratio of isomers in n = 1 by HPLC analysis is shown in Table 2. The area ratio (o / p) of the ortho-orientation and the para-orientation was 120%.

[Examples 3 to 5]
The amine resins obtained in Synthesis Examples 6, 8 and 9 were synthesized in the same manner as in Example 1. The results are shown in Table 2.

[Example 14]
A flask equipped with a thermometer, a cooling tube, a Dean-Stark azeotropic distillation trap, and a stirrer was charged with 147 parts of maleic anhydride, 300 parts of toluene, and 8 parts of methanesulfonic acid, and brought into a heated reflux state. Next, a resin solution prepared by dissolving 190 parts of an aromatic amine resin (A-11) in 95 parts of N-methyl-2-pyrrolidone and 100 parts of toluene was added dropwise over 3 hours while maintaining a reflux state. During this period, the condensed water and toluene that azeotrope under reflux conditions were cooled and separated in the Dean-Stark azeotropic distillation trap, then the organic layer toluene was returned to the inside of the system, and the water was discharged to the outside of the system. After the completion of dropping the resin solution, the reaction was carried out for 6 hours while maintaining a reflux state and performing a dehydration operation.
After completion of the reaction, washing with water was repeated 4 times to remove methanesulfonic acid and excess maleic anhydride, and water was removed from the system by azeotrope of toluene and water under heating and reduced pressure of 70 ° C. or lower. Next, 2 parts of methanesulfonic acid was added, and the reaction was carried out in a heated reflux state for 2 hours. After completion of the reaction, water washing was repeated 4 times until the water was neutralized, and then water was removed from the system by azeotropic boiling of ruen and water under heating and reduced pressure of 70 ° C. or lower, and then toluene was heated and reduced under reduced pressure. After distilling off the solvent until the resin concentration reached about 70-80%, toluene was added to prepare the resin concentration to 60%. As a result, a maleimide solution (V-11) containing a maleimide resin (M-11) was obtained. According to GPC analysis (RI), n = 1 body was 48.1%, and the average n was 1.85. The ratio of isomers in n = 1 by HPLC analysis is shown in Table 2. The area ratio (o / p) of the ortho-orientation and the para-orientation was 127%.
A maleimide resin (M-11) represented by the above formula (1) was obtained by completely distilling off the solvent in 50 parts of the obtained resin solution, especially under heating and reduced pressure. The obtained maleimide resin (M-11) had a softening point of 126 ° C. and an acid value of 9.5 mgKOH / g.

[Comparative Examples 3 and 4, Examples 6 to 10]
The maleimide resins obtained in Comparative Examples 1 and 2 and Examples 1 to 5 were dissolved in toluene so that the resin content was 60% to obtain maleimide resin solutions VSM-1, 2 and VM-1 to 5. The obtained maleimide resin solution was stored at −10 ° C. for 3 months, and then the presence or absence of crystal precipitation was observed. Table 3 shows those in which crystal precipitation was observed as x and those in which no crystal precipitation was observed as 〇.

From Table 3, it was confirmed that the maleimide resin of this embodiment has excellent solution stability.

[Examples 11 and 12, Comparative Examples 5 and 6]
The maleimide resins M-1 and M-3 obtained in Examples 1 and 3 and SM-1 and SM-2 obtained in Comparative Examples 1 and 2 were catalysts (DCP; dikmyl) with respect to 50 parts by weight, respectively. 0.75 parts by weight of peroxide (manufactured by Kayaku Akzo Corporation) was blended and cured at 250 ° C. for 2 hours. A plate of 2.5 mm × 50 mm × 0.25 mm was cut out from the obtained cured product, and the dielectric constant and dielectric loss tangent at frequencies of 1 and 10 GHz were measured using a cavity resonator (ADMS01OC1 manufactured by AET). Shown in 4.

* "-" In the table indicates that it has not been measured.

From Table 4, it was confirmed that the maleimide resin of the present embodiment has excellent dielectric properties not only at 1 GHz but also at 10 GHz.

[Example 13, Comparative Example 7]
50 parts by weight of the maleimide resin M-4 obtained in Example 4 and SM-1 obtained in Comparative Example 1 were catalysts (2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.)). )) 1.5 parts by weight was blended and cured at 250 ° C. for 2 hours. A plate of 50 mm × 50 mm × 0.25 mm was cut out from the obtained cured product, and each at 25 ° C. and 150 ° C. using the balanced disc resonator method (resonator: using a FATEC balanced disc resonator). Table 5 shows the results of measuring the dielectric loss tangent by frequency.

From Table 5, it was confirmed that the maleimide resin of the present embodiment has excellent dielectric properties even in the high frequency region. It was also confirmed that the maleimide resin of the present embodiment has a small difference depending on the temperature and has high environmental resistance.

[Example 15 Comparative Examples 8 and 9]
Using the maleimide resin (M-11) obtained in Example 14, the maleimide resin (SM-1) obtained in Comparative Example 1, and the maleimide resin (SM-2) obtained in Comparative Example 2, Table 6 Various epoxy resins, curing agents, and curing accelerators are mixed in the proportions (parts by weight) described in the above, kneaded with a mixing roll, tableted, and then a resin molded body is prepared by transfer molding and cured at 200 ° C. for 2 hours. rice field. Table 6 shows the results of measuring the physical characteristics of the cured product thus obtained for the following items. In addition, for each cured product, the change in elastic modulus with temperature was measured by a dynamic viscoelastic device (DMA). The results are shown in FIG.

-TMA Tg: Glass transition temperature measured by a thermomechanical characteristic device.
-DMA elastic modulus: Measured by a dynamic viscoelasticity tester (DMA).
-Td5 (5% thermogravimetric reduction temperature): The obtained cured product was crushed into powder, and the thermal decomposition temperature was measured by TG-DTA using a sample of 100 mesh pass and 200 mesh on. The temperature at which the weight was reduced by 5% as measured at a sample amount of 10 mg, a heating rate of 10 ° C./min, and an air amount of 200 ml / hr.
-Bending elastic modulus: Measured in accordance with JIS K-6911.
-Permittivity and dielectric loss tangent: Measured at room temperature using a cavity resonator (manufactured by AET).

E1: NC-3000-L (Nippon Kayaku Epoxy Equivalent 271g / eq)
P1: Kayahard GPH-65 (Nippon Kayaku Co., Ltd. hydroxyl group equivalent 200 g / eq)
C1: 2E4MZ: 2-Ethyl-4-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.)

From the results in Table 6, the cured product of Example 15 has a high elastic modulus in the room temperature to low temperature region, contributes to the rigidity of the substrate, and maintains a high elastic modulus even in the temperature region during solder reflow. Was confirmed. In addition, it can be said that it is excellent in weather resistance due to heat because it has been confirmed that it has high heat resistance (Tg) and excellent stability at the time of heat (heat resistance decomposition Td5). Furthermore, regarding the dielectric properties, it was confirmed that the influence of the deterioration of the dielectric properties due to the epoxy resin compounding could be suppressed, and that both the dielectric constant and the dielectric loss tangent were excellent.

[Example 16, Comparative Example 10]
50 parts by weight of the maleimide resin (M-11) obtained in Example 14 and the maleimide resin (SM-1) obtained in Comparative Example 1 were catalysts (DCP; dicumyl peroxide, chemical agent Nourion Co., Ltd.). (Manufactured by) 0.75 parts by weight, transferred molding at 175 ° C., and then cured at 250 ° C. for 2 hours. A plate of 2.5 mm × 50 mm × 0.25 mm was cut out from the obtained cured product, and its dielectric constant and dielectric loss tangent were immersed in water at room temperature for 24 hours after drying using a cavity resonator (manufactured by AET). After that, the results of measurement at a frequency of 10 GHz are shown in Table 7.

From the results in Table 7, it was confirmed that the cured product of Example 16 had little deterioration in dielectric properties after the water absorption test and had low hygroscopicity, and thus had excellent weather resistance.

This application is based on Japanese Patent Application No. 2020-41840 filed on March 11, 2020, the contents of which are incorporated herein by reference.

Claims

A maleimide resin represented by the following formula (1).
The content of N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide in the maleimide resin is 98 area% or less in GPC area percentage.
In the N, N'-(phenylene-di- (2,2-propylidene) -di-phenylene) bismaleimide, the content of the maleimide compound represented by the following formula (2) is 30 area% or more in HPLC area percentage. Maleimide resin that is less than 60 area%.

(In equation (1), n is the number of repetitions, and the average value thereof is 1 <n <5.)
In the N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide, the area ratio (O / P) of the ortho-orientation and the para-orientation by the HPLC area percentage is 100% or more and 200. The maleimide resin according to claim 1, which is less than%.
In the N, N'-(phenylene-di- (2,2-propanol) -di-phenylene) bismaleimide, the content of the maleimide compound represented by the following formula (3) is less than 50 area% in HPLC area percentage. The maleimide resin according to claim 1 or 2.
A maleimide solution containing the maleimide resin and an organic solvent according to any one of claims 1 to 3, wherein the organic solvent is selected from the group consisting of ketones, hydrocarbons, and esters. Maleimide solution.
A curable resin composition containing the maleimide resin according to any one of claims 1 to 3 or the maleimide solution according to claim 4, which further contains a curing accelerator.
A cured product obtained by curing the maleimide resin according to any one of claims 1 to 3 or the curable resin composition according to claim 5.
An aromatic amine resin is prepared by adding 1 to 12% by weight of protonic acid to aniline and diisopropenylbenzene or di (α-hydroxyisopropyl) benzene with respect to the total amount of aniline and reacting at 140 to 190 ° C. The process of obtaining and
A step of maleimizing the aromatic amine resin, and the like.
The method for producing a maleimide resin according to any one of claims 1 to 3.