JP6925853B2 - New benzoxazine resin composition and cured product thereof - Google Patents

Description

The present invention relates to a novel benzoxazine resin composition and a cured product thereof. More specifically, the present invention relates to a resin composition containing a benzoxazine compound having a benzoxazine ring at both ends of a diphenyl ether group and a cured product thereof.

また、特許文献４には、下記構造のベンゾオキサジン化合物（ｂ）を含む樹脂組成物から硬化物を得ることが記載されている。

しかしながら、これら化合物、例えば、上記ベンゾオキサジン化合物（ｂ）は、中央のメチレン基が酸化されやすく、また、上記ベンゾオキサジン化合物（ａ）、（ｂ）を含む樹脂組成物を硬化させて得られる硬化物はいずれも耐熱性が十分ではないなど、従来公知のベンゾオキサジン化合物を含む樹脂組成物を硬化させた硬化物は、耐熱性等の物性が未だ十分でなく、ベンゾオキサジン樹脂組成物のさらなる改善が求められている。 A benzoxazine compound is a compound synthesized by reacting phenols, amines and formaldehyde, and heat that the benzoxazine ring is ring-opened and polymerized and cured without producing volatile by-products by heating. It is known as a curable resin raw material.
Such a benzoxazine compound is a raw material for a molded product (Patent Document 1), a liquid crystal alignment agent (Patent Document 2), a resin composition for semiconductor encapsulation (Patent Documents 3 and 4) and the like that can be used as a material for an insulating substrate. It is used as.
As a conventionally known benzoxazine compound, Non-Patent Document 1 describes a cured product obtained by curing a benzoxazine compound (a) having the following structure.

Further, Patent Document 4 describes that a cured product is obtained from a resin composition containing a benzoxazine compound (b) having the following structure.

However, in these compounds, for example, the benzoxazine compound (b), the methylene group in the center is easily oxidized, and the curing obtained by curing the resin composition containing the benzoxazine compounds (a) and (b) is obtained. The cured product obtained by curing a resin composition containing a conventionally known benzoxazine compound has insufficient heat resistance and other physical properties, and the benzoxazine resin composition is further improved. Is required.

JP-A-2007-002064 Japanese Unexamined Patent Publication No. 2009-175684 Japanese Unexamined Patent Publication No. 2015-025120 Japanese Unexamined Patent Publication No. 2011-231196

Yangfang Liu et. al, J. Therm. Anal. Calorim. , Vol. 111, pp. 1523-1530 (2013)

An object of the present invention is to provide a resin composition containing a benzoxazine compound and a cured product thereof, which have improved performance such as heat resistance.

As a result of diligent studies to solve the above-mentioned problems, the present inventor has excellent heat resistance by making the chemical structure of the benzoxazine compound a structure having a benzoxazine ring at the 3,4'-position of the diphenyl ether group. The present invention has been completed by finding that a resin can be obtained.

２．１．に記載の樹脂組成物を硬化させてなる硬化物。 The present invention is as follows.
1. 1. A benzoxazine resin composition comprising a benzoxazine compound represented by the general formula (I).

2.1. A cured product obtained by curing the resin composition described in 1.

INDUSTRIAL APPLICABILITY The present invention provides a novel benzoxazine resin composition containing a benzoxazine compound having a benzoxazine ring at the 3,4'-position of a diphenyl ether group and a cured product thereof. This novel benzoxazine resin composition has thermosetting property, and the cured product obtained by curing the novel benzoxazine resin composition is particularly compared with a cured product obtained by curing a resin composition containing a conventionally known benzoxazine compound. The glass transition temperature is high and the heat resistance is extremely excellent. Therefore, it is suitable as a resin raw material for varnishes that can be applied to various substrates, prepregs impregnated with varnishes, printed circuit boards, sealants for electronic parts, electric / electronic molded parts, automobile parts, laminates, paints, resist inks, etc. Can be used for.

前記一般式（Ｉ）で表されるベンゾオキサジン化合物について、その化学構造を下記に例示する。

The benzoxazine compound contained in the resin composition of the present invention is represented by the following general formula (I).

The chemical structure of the benzoxazine compound represented by the general formula (I) is illustrated below.

The method for producing the benzoxazine compound represented by the general formula (I) used in the practice of the present invention is not particularly limited with respect to the starting material and the production method in the production thereof. As described, a known method for producing a benzoxazine compound, such as stirring and mixing a primary amine compound with a phenol compound and formarines in the presence of a solvent and causing a dehydration condensation reaction under heating, is optionally adopted. be able to. Above all, a production method in which a mixed solution of a diaminodiphenyl ether compound and a phenol compound is dehydrated and condensed with formaldehyde to be cyclized to obtain a benzoxazine compound is preferable.

The method for producing the benzoxazine compound represented by the general formula (I) is illustrated below by a reaction formula.

さらに、ホルムアルデヒドとしては、例えば、ホルムアルデヒド水溶液、１，３，５−トリオキサン、パラホルムアルデヒド等を挙げることができる。
ジアミノジフェニルエーテル化合物、フェノール化合物及びホルムアルデヒドの脱水縮合反応において、それぞれの添加モル比（ジアミノジフェニルエーテル化合物／フェノール化合物／ホルムアルデヒド）は、通常１．０／１．６／３．６〜１．０／４．０／４．４の範囲であり、好ましくは１．０／２．０／４．０〜１．０／２．５／４．２の範囲である。 Explaining the raw material compound used in this production method, the diaminodiphenyl ether compound is specifically 3,4'-diaminodiphenyl ether. The phenol compound is a compound represented by the following general formula (II). Examples of the phenol compound represented by the general formula (II) include phenol, p-cresol, o-cresol, and m-cresol.

Further, examples of formaldehyde include an aqueous formaldehyde solution, 1,3,5-trioxane, paraformaldehyde and the like.
In the dehydration condensation reaction of the diaminodiphenyl ether compound, the phenol compound and formaldehyde, the respective addition molar ratios (diaminodiphenyl ether compound / phenol compound / formaldehyde) are usually 1.0 / 1.6 / 3.6 to 1.0 / 4. The range is 0 / 4.4, preferably 1.0 / 2.0 / 4.0 to 1.0 / 2.5 / 4.2.

The reaction is usually carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not inhibit the reaction, but toluene, xylene, ethyl acetate, butyl acetate, chloroform, dichloromethane, THF, dioxane and the like are preferable. These solvents can be used alone or in combination. The amount of the solvent used is not particularly limited as long as it does not interfere with the reaction, but is usually used in the range of 3 to 10 times by weight, preferably 4 to 6 times by weight, that of the diaminodiphenyl ether compound.
The reaction temperature is usually in the range of 70-120 ° C. The reaction pressure may be carried out under normal pressure conditions, under pressure or under reduced pressure.
A catalyst for accelerating the reaction is not particularly required, but an acid catalyst or a base catalyst can be used if necessary. In this case, examples of the acid catalyst that can be used include concentrated hydrochloric acid, hydrochloric acid gas, trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, benzoic acid and a mixture thereof, and examples of the base catalyst that can be used include sodium hydroxide. , Sodium carbonate, triethylamine, triethanolamine and mixtures thereof and the like, but are not limited thereto.
As another embodiment, a procedure for removing the water produced during the reaction from the system can be included. The procedure for removing the water produced from the reaction solution is not particularly limited, and the water produced can be distilled azeotropically with the solvent system in the reaction solution. The generated water can be removed from the reaction system by using, for example, an isobaric dropping funnel equipped with a cock, a Dimroth condenser, a Dean Stark apparatus, or the like.
After the reaction is completed, the reaction-terminated mixture thus obtained can obtain a benzoxazine compound represented by the general formula (I) from this mixture by a known method. For example, after the reaction, the target product can be obtained as a residual liquid by distilling off the residual raw material or solvent from the reaction mixture. It is also conceivable to add the residual liquid to a poor solvent for precipitation, or to add a solvent to the reaction mixture for crystallization and filtration to obtain a powder or granular target product. When the residual raw material is phenol, it can be removed by adding a solvent that separates from water, if necessary, and washing with an alkaline aqueous solution. The benzoxazine compound taken out by the above method can be made into a high-purity product by ordinary purification means such as washing with a solvent or water or recrystallization.

The resin composition of the present invention contains the benzoxazine compound represented by the above general formula (I) as an essential component, and may contain other polymer materials.
The polymer material constituting the resin composition of the present invention is not particularly limited, but may contain raw materials of each of an epoxy resin, a phenol resin, and a bismaleimide resin. Examples of this epoxy resin include orthocresol type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, anthracendihydride type epoxy resin, brominated novolac type epoxy resin and the like. Examples of the phenol resin include a novolak type phenol resin and a bisphenol resin, and examples of the bisphenol resin include a raw material of a bisphenol resin having the following structure.

The resin composition of the present invention contains the benzoxazine compound represented by the general formula (I) in a range of usually 50% by weight or more and 100% by weight or less, preferably 80% by weight or more and 100% by weight or less. More preferably, it is contained in the range of 90% by weight or more and 100% by weight or less. The raw material of the epoxy resin, which is the polymer material constituting the resin composition of the present invention, is in the range of 0% by weight or more and 50% by weight or less, and the raw material of the phenol resin is in the range of 0% by weight or more and 50% by weight or less. The raw material of the bismaleimide resin can be contained in the range of 0% by weight or more and 20% by weight or less.
The resin composition of the present invention can be obtained by adding the benzoxazine compound represented by the general formula (I) to the polymer material as needed, but the addition method is not particularly limited. A conventionally known method can be adopted. For example, a method of adding a polymer material during synthesis or polymerization, a method of adding a resin made of a polymer material to a molten resin melted in, for example, a melt extrusion step, a method of impregnating a resin product made of a polymer material, etc. Can be mentioned.

Subsequently, the cured product of the present invention will be described.
The cured product of the present invention can be obtained by curing a resin composition containing a benzoxazine compound represented by the above general formula (I). The cured product of the present invention may be a cured product obtained by curing only one benzoxazine compound represented by the general formula (I), and may be represented by two or more different general formulas (I). It may be a cured product obtained by curing a mixture composed of a benzoxazine compound. Further, depending on the purpose, the cured product of the present invention can also be obtained by using the raw materials of each of the above-mentioned epoxy resin, phenol resin, and bismaleimide resin.
Examples of the method for producing a cured product of the present invention include a method of heating to a predetermined temperature to cure, a method of heating and melting and pouring into a mold or the like to further heat the mold to cure and mold, and the above general formula (I). ) Is injected into a preheated mold to cure the melt of the benzoxazine compound.
If the resin composition of the present invention contains a residual solvent in the composition, bubbles are generated during curing. To prevent this, it is preferable to perform a vacuum degassing treatment as a pretreatment. The temperature of this vacuum degassing treatment is not particularly limited as long as the resin composition of the present invention is in a molten state, but is 140 to 160 ° C. because curing does not proceed and degassing is easy. The temperature range of is suitable. The pressure of the vacuum degassing treatment is not particularly limited, but it is better to be low (high degree of decompression), and it may be performed in air or in a nitrogen substitution atmosphere. This vacuum degassing process is performed until bubbles cannot be visually confirmed.

The cured product of the present invention can be cured by ring-opening polymerization under the same curing conditions as ordinary benzoxazine. The curing temperature is usually in the temperature range of 140 to 250 ° C., preferably in the temperature range of 160 to 220 ° C., more preferably in the temperature range of 160 to 200 ° C., but the mechanical properties of the obtained cured product are good. In particular, the temperature range is preferably 180 to 200 ° C. When curing is performed in such a temperature range, the reaction time may be about 2 to 10 hours.
The resin composition of the present invention can be cured only by heat, but it is preferable to use a curing accelerator depending on the components other than the benzoxazine compound represented by the general formula (I) and the oil content thereof. The curing accelerator that can be used is not particularly limited, and is, for example, 1,8-diaza-bicyclo [5.4.0] undecene-7, triethylenediamine, tris (2,4,6-dimethylaminomethyl). ) Tertiary amines such as phenol, imidazoles such as 2-ethyl-4-methylimidazole and 2-methylimidazole, triphenylphosphine, tetraphenylphosphonium bromide, tetraphenylphosphonium tetraphenylborate, tetra-n-butylphosphonium Examples thereof include phosphorus compounds such as -o and o-diethylphosphologithioate, quaternary ammonium salts, organometallic salts, and derivatives thereof. These may be used alone or in combination. Among these curing accelerators, it is preferable to use tertiary amines, imidazoles and phosphorus compounds.

^１Ｈ−ＮＭＲ（４００ＭＨｚ）測定（溶媒：CDCl₃）：4.64(s,2H:a) , 4.66(s,2H:a’), 5.37(s,2H:b), 5.39(s,2H:b’), 6.53-6.55(ddd,1H:c), 6.81-7.35(m,15H:others).

^１３Ｃ−ＮＭＲ（４００ＭＨｚ）測定（溶媒：CDCl₃）：50.28(A),50.36(A’),79.21(B),80.14(B’),108.15(H),110.60(I),112.23(J),114.69(C),117.06(K),120.20(L),120.96(M),126.85(N),126.85(N),127,97(O),128.33(P),129.14(Q),130.20(R),149.90(D),151.27(E),154.38(F),159.06(G) Hereinafter, the present invention will be described in more detail with reference to Examples.
<Synthesis example 1>
Synthesis of compound (1) 176.3 g of phenol, 150.0 g of 3,4'-diaminodiphenyl ether, and 750.0 g of toluene were placed in a 2-liter four-necked flask, and a 35% formalin aqueous solution 257 at an internal temperature of 65 ° C. under stirring. 1 g was added dropwise over 35 minutes. After completion of the dropping, simple distillation was performed at 85 ° C. under normal pressure to distill water and toluene, and the distilled toluene was returned to the flask. After adding 35.3 g of phenol, the reaction was carried out at 86 ° C. for 2 hours under reflux.
After completion of the reaction, the internal temperature was lowered to room temperature, 300 g of a 10% aqueous sodium hydroxide solution was added to the reaction mixture, and the mixture was stirred for 20 minutes to separate and remove the aqueous layer. After adding 200 g of toluene to the obtained oil layer, 800 g of a 3.75% sodium hydroxide aqueous solution was added, the mixture was stirred for 20 minutes, allowed to stand, and the aqueous layer was separated and removed.
Next, 300 g of water was added to the obtained oil layer and stirred, and the washing operation for removing the water layer was repeated 6 times. Toluene was distilled off from the washed oil layer under reduced pressure to obtain 185.1 g of the resinous compound (1). The purity of this compound by GPC analysis was 60.4%. In addition, it was confirmed that it was the target compound from ^{the 1 H-NMR analysis result.}

^{1 1} H-NMR (400MHz) measurement (solvent: CDCl ₃ ): 4.64 (s, 2H: a), 4.66 (s, 2H: a'), 5.37 (s, 2H: b), 5.39 (s, 2H: b) '), 6.53-6.55 (ddd, 1H: c), 6.81-7.35 (m, 15H: others).

¹³ C-NMR (400MHz) measurement (solvent: CDCl ₃ ): 50.28 (A), 50.36 (A'), 79.21 (B), 80.14 (B'), 108.15 (H), 110.60 (I), 112.23 (J) ), 114.69 (C), 117.06 (K), 120.20 (L), 120.96 (M), 126.85 (N), 126.85 (N), 127,97 (O), 128.33 (P), 129.14 (Q), 130.20 (R), 149.90 (D), 151.27 (E), 154.38 (F), 159.06 (G)

<Example 1>
63.2 g of the resinous compound (1) synthesized in Synthesis Example 1 was charged in a 200 ml beaker, melted at 140 ° C., and subjected to vacuum degassing treatment.
The vacuum degassed compound (1) is poured into a silicon casting and heated at 140 ° C. for 2 hours, 150 ° C. for 2 hours, 160 ° C. for 2 hours, 180 ° C. for 2 hours, and 200 ° C. for 2 hours. A cured product was obtained.

<Synthesis example 2>
Synthesis of Compound (a) 65.9 g of phenol, 70.0 g of 4,4'-diaminodiphenyl ether, 44.7 g of paraform and 350 g of toluene were placed in a 1-liter four-necked flask and reacted under reflux for 26 hours. After cooling the reaction completion liquid to room temperature, it was added dropwise to a 2-liter four-necked flask charged with 700.0 g of n-heptane to form a precipitate. The resulting precipitate was filtered and dried under reduced pressure to obtain 127.7 g of a powder of compound (a). The purity of this compound by GPC analysis was 59.5%.

<Comparative example 1>
63.0 g of the compound (a) synthesized in Synthesis Example 2 was charged in a 200 ml beaker, melted at 140 ° C., and subjected to vacuum degassing treatment. The vacuum degassed compound (a) is poured into a silicon casting and heated at 140 ° C. for 2 hours, 150 ° C. for 2 hours, 160 ° C. for 2 hours, 180 ° C. for 2 hours, and 200 ° C. for 2 hours. A cured product was obtained.

<Comparative example 2>
73 g of compound (b) manufactured by Shikoku Kasei Kogyo Co., Ltd. was charged in a 200 ml beaker, melted at 150 ° C., and subjected to vacuum degassing treatment. The vacuum degassed compound (b) was poured into a silicon casting and heated at 180 ° C. for 2 hours and at 200 ° C. for 2 hours to obtain a cured product.

<Glass transition temperature (tan δ value)>
The glass transition temperature (tan δ value) of the cured products obtained in Examples 1 and Comparative Examples 1 and 2 was measured by dynamic viscoelasticity measurement, and the obtained measurement results are shown in Table 1.
The dynamic viscoelasticity measurement conditions are as follows.
Dynamic viscoelasticity measuring device: Rheogel-E4000FZ (UBM Co., Ltd)
Heating rate: 2 ° C / min
Frequency: 1Hz
Measurement mode: Bending

From the results in Table 1, it was clarified that the cured product of the present invention had a higher glass transition temperature and excellent heat resistance than the cured product of the conventionally known benzoxazine resin composition.
These effects exhibited by the benzoxazine resin composition of the present invention and the cured product thereof are exceptionally remarkable effects confirmed for the first time by the present inventor through many experiments.

Claims (1)

General formula (I) containing benzoxazine compound represented by be behenate Nzookisajin resin composition cured product obtained by curing the (however, the liquid crystal alignment film and a thermosetting containing the following benzoxazine compounds (a) Composition Excludes thermosetting products obtained by thermosetting the product.)