Reaction product containing benzoxazine, and cured product thereof

Abstract

Provided is a reaction product obtained by a condensation reaction of a phenol, a diamine and formaldehyde, in which the reduction in mass during thermal curing is reduced.　A reaction product according to an embodiment includes a first product represented by formula (1) and a second product represented by formula (2). The peak area of the second product is 5-15% and the total peak area of the first product and the second product is 65-80% both with respect to 100% of the total peak area of the reaction product, said peak areas being determined by HPLC. In the formulas, R1 and R2 represent a methyl group or an ethyl group, R3 and R4 represent an alkyl group or an alkenyl group, p and q represent an integer of 0-4, and the bonding positions of the benzoxazine rings and NH to the biphenyl rings are the 4, 4' positions or the 3, 4' positions.

Description

Reaction products containing benzoxazine, and their cured products

[0001] Embodiments of the present invention relate to reaction products containing benzoxazine and cured products thereof.

[0002] Benzoxazines are compounds containing a benzoxazine ring formed by the condensation reaction of phenols, amines, and formaldehyde. Benzoxazines are thermosetting monomers that harden upon heating through ring-opening polymerization of the benzoxazine ring, and the hardened product forms intramolecular and intermolecular hydrogen bonds.

[0003] For example, Patent Document 1 discloses a benzoxazine having two benzoxazine rings in one molecule, obtained by a condensation reaction of phenol, 4,4'-diaminodiphenylmethane, and paraformaldehyde. Patent Document 2 discloses a benzoxazine having two benzoxazine rings in one molecule, obtained by a condensation reaction of phenol, 4,4'-methylenebis(cyclohexylamine), and formaldehyde.

[0004] Japanese Patent Publication No. 4647398, Japanese Unexamined Patent Publication No. 2022-179472

[0005] The reaction products obtained by the condensation reaction of phenols, diamines, and formaldehyde may include, as the main product, benzoxazine having two benzoxazine rings, as well as by-products such as polymers of the benzoxazine, products resulting from incomplete reactions such as mono-ring products where one benzoxazine ring is not closed, and unreacted starting materials.

[0006] Incidentally, during thermal ring-opening polymerization of benzoxazine, the imine is detached from the zwitterionic intermediate and released as a gas, resulting in a decrease in mass and the formation of voids in the cured product. Therefore, it is necessary to reduce the mass loss during thermal curing.

[0007] The embodiments of the present invention aim to reduce the mass loss during thermal curing of reaction products obtained by condensation reactions of phenols, diamines, and formaldehyde.

[0008] The present inventors, while diligently studying how to reduce the mass loss during thermal curing of reaction products obtained by condensation reactions of phenols, diamines, and formaldehyde, discovered that by including a primary product, which is the main product represented by the following formula (1), and a secondary product, which is a ring-opened product represented by the following formula (2), in specific proportions, it is possible to reduce the mass loss of the reaction products during thermal curing and to increase the glass transition temperature Tg of the cured product, thus completing the present invention.

[0009] The present invention includes the embodiments shown below. [1] A reaction product obtained by condensing phenols, diamines, and formaldehyde, comprising a first product represented by the following formula (1) and a second product represented by the following formula (2), In equations (1) and (2) above, R １ and R ２ Each of these independently represents either a methyl group or an ethyl group, R ３ and R ４ Each of the following independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and each independently represents an integer from 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position, and the peak area of ​​the second product is 5 to 15% of the total peak area of ​​the reaction product as measured by HPLC, provided that the reaction product contains a solvent, the total peak area excluding the solvent is 100%, and the sum of the peak areas of the first and second products is 65 to 80%.

[0010] [2] The first product is represented by the following formula (3), and the second product is represented by the following formula (4), In equations (3) and (4) above, R １ and R ２ Each of these independently represents either a methyl group or an ethyl group, R ３ and R ４ The reaction product described in [1], wherein each of the elements independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and p and q independently represent integers from 0 to 2.

[0011] [3] The first product is represented by the following formula (5), and the second product is represented by the following formula (6). In the formulas (5) and (6), R １ and R ２ each independently represents a methyl group or an ethyl group, and R ３ and R ４ each independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and is the reaction product according to [1].

[0012] [4] A cured product obtained by curing the reaction product according to any one of [1] to [3].

[0013] According to an embodiment of the present invention, in a reaction product obtained by subjecting phenols, diamines, and formaldehyde to a condensation reaction, it is possible to reduce the mass loss during thermosetting and to increase the glass transition temperature Tg of the cured product.

[0014] UV chromatogram of the reaction product obtained in Example 1 UV chromatogram of toluene Mass chromatogram of the reaction product obtained in Example 1 Mass chromatogram of the component (first product) having a molecular weight of 529 among the reaction products obtained in Example 1 Mass chromatogram of the component (second product) having a molecular weight of 517 among the reaction products obtained in Example 1 Chromatogram of the reaction product obtained in Example 1

[0015] The reaction product according to the present embodiment is obtained by a condensation reaction of phenols, diamines, and formaldehyde, and includes a first product represented by the following formula (1) and a second product represented by the following formula (2).

[0016] In the formulas (1) and (2), R １ and R ２ each independently represents a methyl group or an ethyl group, more preferably a methyl group. R １ and R ２ When a plurality of them exist in one molecule, they may be the same or different. p and q each independently represent an integer of 0 to 4, more preferably an integer of 0 to 2, and still more preferably 1.

[0017] In Formula (1) and Formula (2), R ３ and R ４ each independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, more preferably represents an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 or 3 carbon atoms. These alkyl groups and alkenyl groups may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group. Examples of the alkenyl group include a vinyl group, a 1-propenyl group, an allyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 2-methylallyl group, a 1-methylallyl group, and a 2-methyl-1-propenyl group.

[0018] R ３ and R ４ When they are alkenyl groups, they do not react by the thermal ring-opening polymerization of benzoxazine, but can be used for copolymerization with other polymerizable monomers.

[0019] In Formula (1) and Formula (2), the bonding position of the benzoxazine ring or NH (amino group of the unclosed benzoxazine ring) to the biphenyl group (specifically, a biphenyl group which may have substituents R １ and / or R ２ ) is the 4,4'-position or the 3,4'-position, preferably the 4,4'-position.

[0020] The first product represented by Formula (1) is the main product as the target product, which is composed of 1 molecule of diamine, 2 molecules of phenols, and 4 molecules of formaldehyde, and has 2 benzoxazine rings in 1 molecule. The second product represented by Formula (2) is a ring-opened product in which 1 of the 2 benzoxazine rings of the first product is not closed but ring-opened.

[0021] The first product is preferably a compound represented by formula (3) below, and the second product is preferably a compound represented by formula (4) below. These are cases where the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position. When it is at the 4,4' position, the compound has a linear and rigid structure, and it is thought that the glass transition temperature of the cured product is further improved.

[0022] In equations (3) and (4), R １ , R ２ , R ３ and R ４ R is in equations (1) and (2). １ , R ２ , R ３ and R ４ This is the same as above. p and q may each be an integer between 0 and 4, but are preferably integers between 0 and 2, and more preferably 1.

[0023] The first product is more preferably a compound represented by the following formula (5), and the second product is more preferably a compound represented by the following formula (6). Thus, substituent R １ and R ２ It is believed that by having this at the 2,2' position of the biphenyl group, the rotation of the benzene rings in the biphenyl group is suppressed by steric hindrance, further improving the glass transition temperature of the cured product.

[0024] In equations (5) and (6), R １ , R ２ , R ３ and R ４ R is in equations (1) and (2). １ , R ２ , R ３ and R ４ It is the same as this.

[0025] In the reaction product according to this embodiment, the content of the first product and the second product is as follows: The peak area of ​​the second product is 5 to 15% of the total peak area of ​​the reaction product by HPLC (however, if the reaction product contains a solvent, the total peak area excluding the solvent is 100%), and the sum of the peak areas of the first product and the second product is 65 to 80%.

[0026] By including the target product (first product) and the mono-ring-opened product (second product) in these proportions, the mass loss of the reaction product during thermal curing can be reduced, and the glass transition temperature (Tg) of the cured product can be increased. The reason for this is presumed to be as follows, although this is not intended to be the sole reason: Since the mono-ring-opened product has a phenolic hydroxyl group, it undergoes thermal ring-opening polymerization during thermal curing and also functions as a catalyst, thus improving the reactivity of thermal ring-opening polymerization. It is thought that the inclusion of such a mono-ring-opened product and the target product (first product) in the above amounts moderately promotes the thermal ring-opening polymerization reaction, thereby increasing the glass transition temperature during curing and suppressing the mass loss due to imine detachment. Furthermore, since the biphenyl group derived from the diamine is directly bonded to the benzene rings, it has a more rigid structure compared to those bonded via alkylene groups such as methylene groups, which is thought to improve the glass transition temperature.

[0027] More specifically, by having a combined peak area of ​​65% or more for the first and second products, the amount of benzoxazine polymer, a by-product not involved in curing, can be reduced, thereby improving the glass transition temperature. By having a combined peak area of ​​80% or less for the first and second products, the mass loss of the reaction products during thermal curing can be reduced. The combined peak area of ​​the first and second products is more preferably 66-75%, more preferably 67-72%, and even more preferably 68-71%.

[0028] Furthermore, a peak area of ​​5% or more for the secondary product reduces the mass loss of the reaction product during thermal curing and improves the glass transition temperature of the cured product. A peak area of ​​15% or less for the secondary product improves the glass transition temperature of the cured product. The peak area of ​​the secondary product is more preferably 8-15%, more preferably 9-14%, and even more preferably 10-13.5%.

[0029] The peak area of ​​the first product is not particularly limited, but is preferably 50-70%, more preferably 52-67%, more preferably 54-65%, and even more preferably 55-64%.

[0030] The peak area of ​​the second product, the sum of the peak areas of the first and second products, and the peak area of ​​the first product, relative to 100% of the total peak area of ​​the reaction products obtained by HPLC, are determined by performing HPLC (high-performance liquid chromatography) on the reaction products. For the chromatogram obtained by HPLC, the sum of the peak areas of all peaks (except, if the reaction product contains a solvent, the peak areas of all peaks excluding those originating from the solvent) is taken as 100%, and the peak area ratio of each peak is calculated. This allows for the determination of the peak area ratio of the peaks originating from the first product and the peak area ratio of the peaks originating from the second product. The sum of the peak areas of the first and second products is obtained by calculating the sum of these ratios. Details regarding the HPLC measurement conditions are described in detail in the Examples section.

[0031] The reaction product according to this embodiment is obtained by condensing phenols, diamines, and formaldehyde, and is a mixture (and therefore also called the reaction product composition) containing a first product and a second product, both of which are benzoxazines. In addition to the first product, which is the main product, and the second product, which is a by-product, the reaction product may also contain polymers (including oligomers) of the benzoxazine, other by-products, unreacted raw materials, and a solvent. Examples of other by-products include compounds obtained by dehydration condensation of one molecule of diamine and three or four molecules of phenols via formaldehyde, and compounds obtained by dehydration condensation of two molecules of diamine and three molecules of phenols via formaldehyde. These may have one or more benzoxazine rings, and some of the benzoxazine rings may be open rather than closed.

[0032] If the reaction product contains a solvent, examples of solvents include organic solvents capable of dissolving benzoxazine, such as toluene, xylene, cumene, monochlorobenzene, methyl ethyl ketone, ethyl acetate, butyl acetate, chloroform, dichloromethane, THF, dioxane, and dimethylformaldehyde. These may be used individually or in combination of two or more. In this case, the concentration of the reaction product solution is not particularly limited and may be, for example, 30 to 65% by mass or 40 to 60% by mass.

[0033] The reaction product according to this embodiment may be a reaction product obtained by condensing phenols, diamines, and formaldehyde, or it may be obtained by liquid-liquid washing, recrystallization, column purification, etc.

[0034] The method for producing the above reaction product is not particularly limited. For example, one method involves stirring and mixing phenols, diamines, and formaldehyde in the presence of a solvent, and then carrying out a dehydration condensation reaction under heating. Preferably, this method involves adding formaldehyde to a mixed solution obtained by dissolving phenols and diamines in a solvent such as toluene, carrying out a dehydration condensation reaction under heating, and then further increasing the temperature and aging at a high temperature.

[0035] Examples of phenols include compounds represented by formula (7) below, examples of diamines include compounds represented by formula (8) below, and examples of formaldehyde include paraformaldehyde, i.e., (HClO) ｎ These are some examples.

[0036] In equation (7), R ５ R in the above formula (1) is ３ and R ４ This is equivalent to, that is, it represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and more preferably, an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 or 3 carbon atoms.

[0037] In equation (8), R １ , R ２ p and q are R in formula (1) above, respectively. １ , R ２ , is the same as p and q, that is, R ２ and R ３ Each independently represents a methyl group or an ethyl group, and p and q each independently represent an integer from 0 to 4. Biphenyl group (in detail, substituent R １ and / or R ２ NH for a biphenyl group that may have ２ The bonding position is at the 4,4' position or the 3,4' position, preferably at the 4,4' position.

[0038] Specific examples of phenols of formula (7) include 2-methylphenol, 2-ethylphenol, 2-propylphenol, 2-isopropylphenol, 2-tert-butylphenol, 2-vinylphenol, 2-propenylphenol, 2-allylphenol, 2-isopropenylphenol, 2-(3-butenyl)phenol, and 2-(2-methyl-2-propenyl)phenol. Any one or two or more of these may be used.

[0039] Specific examples of the diamine in formula (8) include 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 3,4'-diamino-2,2'-dimethylbiphenyl, 3,4'-diamino-3',5-dimethylbiphenyl, and 3,4'-diamino-2',6-dimethylbiphenyl. Any one or more of these may be used.

[0040] Regarding the ratio of phenols, diamines, and formaldehyde, since the target product represented by formula (1) is obtained by reacting 2 moles of phenols and 4 moles of formaldehyde with 1 mole of diamine, the amount of charge can be set based on this. For example, it is preferable to charge 2.0 to 2.5 moles of phenols per mole of diamine, more preferably 2.0 to 2.2 moles, and even more preferably 2.0 to 2.1 moles. It is preferable to charge 3.9 to 5.0 moles of formaldehyde per mole of diamine, more preferably 4.0 to 4.5 moles, and even more preferably 4.0 to 4.3 moles. Reducing the amount of formaldehyde tends to increase the content of the secondary product, while increasing the amount of formaldehyde tends to increase the content of the primary product and decrease the content of the secondary product.

[0041] The temperature during the dehydration condensation reaction is not particularly limited; for example, it may be 70-90°C or 75-85°C. The temperature during aging is not particularly limited; for example, it may be 95-130°C, 100-120°C or 105-115°C. The aging time is not particularly limited; for example, it may be 1-20 hours, 3-15 hours or 5-12 hours. Increasing the aging time tends to reduce the content of the secondary product.

[0042] The concentration of the reactants when carrying out a dehydration condensation reaction in the presence of a solvent is not particularly limited; for example, it may be 30-65% by mass or 40-60% by mass. Increasing the concentration tends to reduce the amount of the first product, and also tends to reduce the total amount of the first and second products.

[0043] The reaction product according to this embodiment contains benzoxazine, and is a thermosetting resin that hardens (thermally cured) by thermal ring-opening polymerization of the benzoxazine as a monomer. The cured product according to this embodiment is obtained by curing the reaction product, and may be used alone or in combination with other resins. In other words, the reaction product according to one embodiment can constitute a thermosetting composition either alone or in combination with other resins.

[0044] The thermosetting composition contains the above-mentioned reaction product, and may also contain a thermosetting resin and / or a thermoplastic resin together with the reaction product. The thermosetting composition may also contain various known additives such as crosslinking agents, curing accelerators, and colorants.

[0045] The present invention will be described in more detail below based on examples and comparative examples, but it is not limited thereto.

[0046] <Measurement and Evaluation Method> The content of the first and second products in the reaction product can be determined by assigning the peaks derived from the first and second products to the chromatogram obtained by HPLC, and then determining the peak area ratio of each peak based on the result. In this example, the measurement was performed as follows.

[0047] [Assignment of HPLC Peaks] The reaction product obtained in Example 1 or toluene was dissolved in acetonitrile to a concentration of approximately 0.2 mg / ml, and measured using a high-performance liquid chromatograph (HPLC) (Agilent 1200 series, manufactured by Agilent Technologies) equipped with a reversed-phase column (Inertsil ODS-3, 2.1 × 150 mm, particle size 3 μm, manufactured by GL Sciences Co., Ltd.). The measurement conditions were a column oven temperature of 40°C and a flow rate of 0.3 ml / min. A diode array (DAD) detector (G1315B, manufactured by Agilent Technologies, detection wavelength 254 nm) and an atmospheric pressure ionization time-of-flight mass spectrometer (JMS-T100LP, manufactured by JEOL Ltd.) were used as detectors. The needle voltage of the atmospheric pressure ionization time-of-flight mass spectrometer was set to 2500V, the detector voltage to 2000V, the peak voltage to 2100V, and the orifice 1 voltage to 50V.

[0048] Figure 1 shows the UV chromatogram of the reaction product obtained in Example 1 as detected by a DAD detector, and Figure 2 shows the UV chromatogram of toluene. Figure 3 shows the mass chromatogram of the reaction product obtained in Example 1 as detected by a mass spectrometer, Figure 4 shows the mass chromatogram of the component with a molecular weight of 529, and Figure 5 shows the mass chromatogram of the component with a molecular weight of 517.

[0049] From Figures 1 and 2, the peak at elution time 1.73 minutes in Figure 1 was assigned to toluene. Next, from Figures 3 to 5, the peak at elution time 3.03 minutes in Figure 3 was assigned to the first product, and the peak at elution time 2.56 minutes was assigned to the second product. Furthermore, since the peaks in Figures 1 and 3 are similar in shape, the peak at elution time 2.83 minutes in Figure 1 was assigned to the first product, and the peak at elution time 2.34 minutes was assigned to the second product.

[0050] Next, the reaction product obtained in Example 1 was dissolved in acetonitrile to a concentration of approximately 0.2 mg / ml, and measured using an integrated liquid chromatograph (model name: LC-2050C, detector type: UV, manufactured by Shimadzu Corporation, detection wavelength 254 nm) equipped with a reversed-phase column (Inertsil ODS-3, 4.6 × 150 mm, particle size 5 μm, manufactured by GL Sciences Co., Ltd.). The measurement conditions were a column oven temperature of 40°C and a flow rate of 1.44 ml / min. The obtained chromatogram is shown in Figure 6. Since the chromatogram in Figure 6 is similar in shape to the chromatogram in Figure 1, it was determined that in the chromatogram in Figure 6, the peak at elution time 1.55 minutes was toluene, the peak at elution time 2.56 minutes was the first product, and the peak at elution time 2.10 minutes was the second product.

[0051] [Calculation of the sum of the peak areas of the first and second products and the peak area of ​​the second product] The reaction products obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were dissolved in acetonitrile to a concentration of approximately 0.2 mg / ml, and HPLC measurements were performed using an integrated liquid chromatograph (model name: LC-2050C, detector type: UV, manufactured by Shimadzu Corporation, detection wavelength 254 nm) equipped with a reversed-phase column (Inertsil ODS-3, 4.6 × 150 mm, particle size 5 μm, manufactured by GL Sciences Co., Ltd.). The measurement conditions were a column oven temperature of 40°C and a flow rate of 1.44 ml / min.

[0052] For the obtained chromatogram, the area ratio of each peak was calculated so that the sum of the peak areas of all peaks except those derived from toluene equaled 100%. The peak area ratio (%) of the peak derived from the first product and the peak area ratio (%) of the peak derived from the second product were determined, and the sum of these ratios was calculated to find the total peak area (%) of the first and second products.

[0053] [Mass Loss Rate] Approximately 2 g of the reaction products obtained in Examples 1-5 and Comparative Examples 1-4 were placed in aluminum cups with an upper diameter of 60 mm, a lower diameter of 54 mm, and a depth of 16 mm, and the solvent was removed by distillation after heating at 120°C for 30 minutes. Then, using a differential thermobalance (Rigaku Corporation, Thermo Plus EVO TG8120), the temperature was raised from room temperature to 250°C at a heating rate of 10°C / min, and the mass loss rate was measured after holding at 250°C for 1 hour.

[0054] [Glass Transition Temperature (Tg)] 7.5 g of the reaction products obtained in Examples 1-5 and Comparative Examples 1-4 were placed in aluminum cups with an upper diameter of 60 mm, a lower diameter of 54 mm, and a depth of 16 mm, and heated on a hot plate at 120°C for 1 hour to remove the solvent by distillation. Furthermore, the hot plate was heated to 250°C for 1 hour to perform thermal curing, and a flat plate was prepared by allowing it to cool at room temperature. A test piece with a width of 5 mm, a thickness of 1 mm, and a length of 30 mm was prepared from the obtained flat plate. Next, the glass transition temperature was measured using a dynamic viscoelasticity measuring device: Rheogel-E4000 (manufactured by UBM Co., Ltd.). For the test piece, the maximum value of the loss tangent (tanδ) measured under the conditions of a tensile sine wave, dynamic strain of 5 μm, frequency of 1 Hz, and heating rate of 3°C / min was determined as the glass transition temperature.

[0055] <Example 1> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 131.1 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 165.7 g of 2-allylphenol, and 377.4 g of toluene were added and dissolved at 75°C. Next, 80.6 g of 92% by mass paraformaldehyde was added in five portions, and the reaction mixture was heated to remove the water produced by the dehydration condensation reaction. The reaction mixture was further heated to 105-110°C and the reaction was continued for 6 hours. After the reaction mixture was cooled to room temperature, 102.0 g of toluene was added to dilute it. 151.0 g of 10% by mass aqueous sodium hydroxide solution and 37.7 g of isopropyl alcohol (IPA) were added, and the mixture was stirred for 15 minutes. After standing, the aqueous layer was separated and removed twice, and then 70.0 g of toluene was added to the resulting organic layer to dilute it. 151.0 g of water and 37.7 g of IPA were added to the mixture, stirred for 15 minutes, and allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50% by mass. HPLC analysis of the obtained reaction product revealed that the peak area of ​​the first product, represented by formula (9) below, was 56.9%, the peak area of ​​the second product, represented by formula (10) below, was 13.1%, and the total peak area of ​​the first and second products was 70.0%.

[0056] <Example 2> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 249.0 g of toluene were added and dissolved at 75°C. Next, 46.8 g of 92% by mass paraformaldehyde was added in five portions, and the reaction solution was heated to remove the water produced by the dehydration condensation reaction. The reaction solution was further heated to 105-110°C and the reaction was continued for 6 hours, after which the reaction solution was cooled to room temperature (the reaction solution obtained here is called "reaction solution A"). 200 g of this reaction solution A was taken and diluted with 23.0 g of toluene. 42.8 g of 10% by mass sodium hydroxide aqueous solution and 10.7 g of IPA were added and stirred for 15 minutes, and the aqueous layer was separated and removed twice. Then, 17.4 g of toluene was added to the resulting organic layer and diluted. 42.8 g of water and 10.7 g of IPA were added to the mixture, stirred for 15 minutes, and then allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50% by mass. HPLC analysis of the obtained reaction product revealed that the peak area of ​​the second product was 12.4%, and the combined peak area of ​​the first and second products was 68.2%.

[0057] <Example 3> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 249.0 g of toluene were added and dissolved at 75°C. Next, 53.2 g of 91% by mass paraformaldehyde was added in five portions, and the reaction mixture was heated to remove the water produced by the dehydration condensation reaction. The reaction mixture was further heated to 105-110°C and the reaction was continued for 6 hours, after which the reaction mixture was cooled to room temperature. 200 g of this reaction mixture was taken and diluted with 28.2 g of toluene. 42.5 g of 10% by mass sodium hydroxide aqueous solution and 10.6 g of IPA were added and stirred for 15 minutes, then allowed to stand to separate and remove the aqueous layer. This process was repeated twice, and then 13.5 g of toluene was added to the resulting organic layer to dilute it. 42.5 g of water and 10.6 g of IPA were added to the mixture, stirred for 15 minutes, and allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product showed that the peak area of ​​the second product was 10.8%, and the combined peak area of ​​the first and second products was 74.1%.

[0058] <Example 4> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 249.0 g of toluene were added and dissolved at 75°C. Next, 47.9 g of 92% by mass paraformaldehyde was added in five portions, and the reaction mixture was heated to remove the water produced by the dehydration condensation reaction. The reaction mixture was further heated to 105-110°C and the reaction was continued for 5 hours. After the reaction mixture was cooled to room temperature, 89.7 g of toluene was added to dilute it. 99.6 g of 10% by mass sodium hydroxide aqueous solution and 24.9 g of IPA were added and stirred for 15 minutes. After standing, the aqueous layer was separated and removed twice, and then 44.7 g of toluene was added to the resulting organic layer to dilute it. 99.6 g of water and 24.9 g of IPA were added to the mixture, stirred for 15 minutes, and allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product showed that the peak area of ​​the second product was 15.0%, and the combined peak area of ​​the first and second products was 66.6%.

[0059] <Example 5> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 106.7 g of toluene were added and dissolved at 75°C. Next, 46.8 g of 92% by mass paraformaldehyde was added in five portions, and the reaction mixture was heated to remove the water produced by the dehydration condensation reaction. The reaction mixture was further heated to 105-110°C and the reaction was continued for 4 hours, after which the reaction mixture was cooled to room temperature. 140 g of this reaction mixture was taken, heated to 75°C, and 2.8 g of 92% by mass paraformaldehyde was added. The reaction mixture was then further heated to 105-110°C and the reaction was continued for 2 hours. After the reaction mixture was cooled to room temperature, 93.9 g of toluene was added to dilute it. 43.1 g of 10% by mass sodium hydroxide aqueous solution and 10.8 g of IPA were added to the mixture and stirred for 15 minutes. After allowing it to stand, the aqueous layer was separated and removed. This procedure was repeated twice, and then 10.7 g of toluene was added to the resulting organic layer to dilute it. 43.1 g of water and 10.8 g of IPA were added to this mixture and stirred for 15 minutes. After allowing it to stand, the aqueous layer was separated and removed. This procedure was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product showed that the peak area of ​​the second product was 5.5%, and the combined peak area of ​​the first and second products was 69.6%.

[0060] <Comparative Example 1> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 82.8 g of 2-allylphenol, 53.8 g of 92% by mass paraformaldehyde, and 164.2 g of toluene were added and dissolved at 75°C. Next, a solution of 43.7 g of 4,4'-diamino-2,2'-dimethylbiphenyl and 27.6 g of 2-allylphenol dissolved in 43.7 g of toluene at 70°C was added dropwise over 6 hours, and the reaction mixture was heated to remove the water produced by the dehydration condensation reaction. The reaction mixture was further heated to 105-110°C and the reaction was continued for 4 hours, after which the reaction mixture was cooled to room temperature. 49.4 g of 20% by mass sodium hydroxide aqueous solution and 12.4 g of IPA were added to the mixture and stirred for 15 minutes, then allowed to stand and the aqueous layer was separated and removed. This procedure was repeated three times. Then, 49.4 g of water and 12.4 g of IPA were added to the resulting organic layer and stirred for 15 minutes, then allowed to stand and the aqueous layer was separated and removed. This procedure was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product showed that the peak area of ​​the second product was 5.7%, and the combined peak area of ​​the first and second products was 85.8%.

[0061] <Comparative Example 2> 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 106.7 g of toluene were added to a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, and dissolved at 75°C. Next, 47.9 g of 92% by mass paraformaldehyde was added in five portions, and the reaction solution was heated to remove the water produced by the dehydration condensation reaction. The reaction solution was further heated to 105-110°C and the reaction was continued for 4 hours, after which the reaction solution was cooled to room temperature. 140 g of this reaction solution was taken and diluted with 91.6 g of toluene. 43.0 g of 10% by mass sodium hydroxide aqueous solution and 10.8 g of IPA were added and stirred for 15 minutes, then allowed to stand to separate and remove the aqueous layer. This process was repeated twice, and then 13.3 g of toluene was added to the resulting organic layer to dilute it. 43.0 g of water and 10.8 g of IPA were added to the mixture, stirred for 15 minutes, and allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product showed that the peak area of ​​the second product was 12.3%, and the combined peak area of ​​the first and second products was 63.7%.

[0062] <Comparative Example 3> In a 1 L reactor equipped with a condenser, a Dean-Stark apparatus, and a stirrer, 86.5 g of 4,4'-diamino-2,2'-dimethylbiphenyl, 109.3 g of 2-allylphenol, and 106.7 g of toluene were added and dissolved at 75°C. Next, 47.9 g of 92% by mass paraformaldehyde was added in five portions, and the reaction solution was heated to remove the water produced by the dehydration condensation reaction. The reaction solution was further heated to 105-110°C and the reaction was continued for 6 hours, after which the reaction solution was cooled to room temperature. 140 g of this reaction solution was taken and diluted with 98.0 g of toluene. 43.0 g of 10% by mass sodium hydroxide aqueous solution and 10.8 g of IPA were added and stirred for 15 minutes, then allowed to stand to separate and remove the aqueous layer. This process was repeated twice, and then 13.6 g of toluene was added to the resulting organic layer to dilute it. 43.0 g of water and 10.8 g of IPA were added to the mixture, stirred for 15 minutes, and then allowed to stand. This process of separating and removing the aqueous layer was repeated five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator to obtain the reaction product as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction product revealed that the peak area of ​​the second product was 15.6%, and the combined peak area of ​​the first and second products was 72.3%.

[0063] <Comparative Example 4> 200 g of reaction solution A from Example 2 was taken, heated to 75°C, and 2.8 g of 92% by mass paraformaldehyde was added. The reaction solution was then heated further to 105-110°C and the reaction was continued for 2 hours. After the reaction solution was cooled to room temperature, 22.4 g of toluene was added to dilute it. 42.8 g of 10% by mass sodium hydroxide aqueous solution and 10.7 g of IPA were added, and the mixture was stirred for 15 minutes. The aqueous layer was separated and removed twice. Then, 25.1 g of toluene was added to the resulting organic layer to dilute it. 42.8 g of water and 10.7 g of IPA were added, and the mixture was stirred for 15 minutes. The aqueous layer was separated and removed five times. The water and IPA from the resulting organic layer were removed by vacuum distillation using a rotary evaporator, and the reaction product was obtained as a toluene solution with a concentration of approximately 50%. HPLC analysis of the obtained reaction products revealed that the peak area of ​​the second product was 3.7%, and the combined peak area of ​​the first and second products was 74.5%.

[0064] The mass loss rate and glass transition temperature were measured for the reaction products of Examples 1-5 and Comparative Examples 1-4. The results are shown in Tables 1 and 2.

[0065]

[0066]

[0067] In Comparative Example 1, the sum of the peak areas of the first and second products exceeded the specified value, resulting in a large mass loss rate. In Comparative Example 2, the sum of the peak areas of the first and second products was below the specified value, resulting in a low glass transition temperature of the cured product. In Comparative Example 3, the peak area of ​​the second product exceeded the specified value, resulting in a low glass transition temperature of the cured product. In Comparative Example 4, the peak temperature of the second product was below the specified value, resulting in a large mass loss rate and a low glass transition temperature of the cured product. Thus, in the comparative examples, at least one of an increase in the mass loss rate and a decrease in the glass transition temperature was observed, whereas in Examples 1 to 5, the mass loss rate was below a certain value and the glass transition temperature of the cured product was above a certain value. Therefore, with the reaction products of the examples, it was possible to obtain a heat-resistant cured product while suppressing outgassing during thermal curing.

[0068] Furthermore, the various numerical ranges described in this specification can be any combination of their upper and lower limits, and all such combinations are described herein as preferred numerical ranges. Also, the description of a numerical range as "X to Y" means X or greater and Y or less.

[0069] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their omissions, substitutions, and modifications are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0070] The reaction product according to this embodiment can produce a heat-resistant cured product while suppressing outgassing during thermal curing, and can therefore be used, for example, in printed circuit board materials, semiconductor encapsulating resins, matrix resins for composite materials, paints, adhesives, and the like.

Claims

1. A reaction product obtained by condensing phenols, diamines, and formaldehyde, comprising a first product represented by the following formula (1) and a second product represented by the following formula (2), In equations (1) and (2) above, R １ and R ２ Each of these independently represents either a methyl group or an ethyl group, R ３ and R ４ Each of the following independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and each independently represents an integer from 0 to 4, and the bond position of the benzoxazine ring or NH to the biphenyl group is at the 4,4' position or the 3,4' position, and the peak area of ​​the second product is 5 to 15% of the total peak area of ​​the reaction product as measured by HPLC, provided that the reaction product contains a solvent, the total peak area excluding the solvent is 100%, and the sum of the peak areas of the first and second products is 65 to 80%.

2. The first product is represented by the following formula (3), and the second product is represented by the following formula (4), In equations (3) and (4) above, R １ and R ２ Each of these independently represents either a methyl group or an ethyl group, R ３ and R ４ The reaction product according to claim 1, wherein each of the elements independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms, and p and q each independently represent an integer from 0 to 2.

3. The first product is represented by the following formula (5), and the second product is represented by the following formula (6). In the formula (5) and formula (6), R １ and R ２ each independently represents a methyl group or an ethyl group, and R ３ and R ４ each independently represents an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 2 to 4 carbon atoms. The reaction product according to claim 1.

4. A cured product obtained by curing the reaction product according to any one of claims 1 to 3.

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