Cured epoxy resin object, epoxy resin composition, prepreg, laminate, and printed wiring board

Abstract

Provided are: an epoxy resin composition which attains both low dielectric characteristics and low melt viscosity and from which a cured object exhibiting excellent dielectric characteristics can be obtained; and a cured epoxy resin object using the same.　Provided is a cured epoxy resin object for use as an insulating material. When components contained in the cured object are separated into three components, i.e., a 120°C-hard component, a 120°C-middle component, and a 120°C-soft component, in ascending order of spin-spin relaxation time on the basis of a free induction decay curve at 120°C determined by a solid echo method using pulse NMR, and when the components contained in the cured object are separated into three components, i.e., a 160°C-hard component, a 160°C-middle component, and a 160°C-soft component, in ascending order of spin-spin relaxation time on the basis of a free induction decay curve at 160°C determined by the solid echo method using pulse NMR, then the content of the 160°C-hard component is 10% or higher but less than 60% relative to a total of 100% of the content of the 160°C-hard component, the content of the 160°C-middle component, and the content of the 160°C-soft component, the ratio of the spin-spin relaxation time of the 160°C-hard component to the spin-spin relaxation time of the 120°C-hard component is 1.30 or greater, the spin-spin relaxation time of the 120°C-hard component is 10.0-22.0 microseconds, and the spin-spin relaxation time of the 160°C-hard component is 18.0-30.0 microseconds.

Description

Epoxy resin cured products, epoxy resin compositions, prepregs, laminates, and printed circuit boards

[0001] The present invention relates to an epoxy resin cured product having excellent low dielectric properties, an epoxy resin composition comprising an epoxy resin with excellent low melt viscosity as an essential component, and prepregs, laminates, and printed circuit boards obtained from the epoxy resin composition.

[0002] Epoxy resins are used in a wide range of applications, including paints, civil engineering adhesives, casting, electrical and electronic materials, and film materials, due to their excellent adhesive properties, flexibility, heat resistance, chemical resistance, insulation, and curing reaction. In particular, they are widely used in printed circuit board applications, a type of electrical and electronic material, by imparting flame retardancy to epoxy resins.

[0003] In recent years, information devices have become smaller and more high-performance at an accelerating pace, and consequently, materials used in the fields of semiconductors and electronic components are required to have higher performance than ever before. In particular, epoxy resin compositions used as materials for electrical and electronic components require low dielectric properties to accommodate the thinning and high-performance nature of substrates.

[0004] On the other hand, epoxy resins require not only low dielectric properties but also low melt viscosity to ensure the embedding of circuits on the substrate. To date, to improve the dielectric properties (loss tangent) of epoxy resins for laminate applications, for example, dicyclopentadienephenol resins with an aliphatic skeleton have been proposed (Patent Documents 1 and 2). However, these have had little effect in improving the dielectric loss tangent, and the low melt viscosity has not been satisfactory. Furthermore, it has been proposed to improve dielectric properties by using modified dicyclopentadienephenol resins (Patent Documents 3 and 4). However, this has not achieved both low dielectric properties and low melt viscosity. In addition, bisphenol C type epoxy resin has been proposed for low melt viscosity (Patent Document 5). However, although the low melt viscosity has been improved, the low dielectric properties have not been satisfactory.

[0005] Japanese Patent Publication No. 2001-240654, Japanese Patent Publication No. Hei 5-339341, Japanese Patent Publication No. 2016-69524, International Publication No. 2020 / 129724, International Publication No. 2024 / 190555

[0006] Therefore, the problem that the present invention aims to solve is to provide an epoxy resin composition that yields a cured product exhibiting excellent low melt viscosity and excellent low dielectric properties, and an epoxy resin cured product using the same.

[0007] To solve the above problems, the inventors conducted various studies and found that characteristic values ​​based on the content of specific components and relaxation time at specific temperatures of the cured product, obtained using pulsed NMR measured by the solid echo method, are closely related to the low dielectric properties of the cured product. Furthermore, they found that epoxy resin compositions and epoxy resins that yield such cured products also exhibit excellent low melt viscosity properties, thus completing the present invention.

[0008] In other words, the present invention relates to an epoxy resin cured product used as an insulating material, wherein, based on a free induction decay curve at 120°C obtained using pulsed NMR measured by the Solid echo method, the components contained in the cured product are separated into three components in order of increasing spin-spin relaxation time: a hard component at 120°C, a middle component at 120°C, and a soft component at 120°C, and, based on a free induction decay curve at 160°C obtained using pulsed NMR measured by the Solid echo method, the components contained in the cured product are separated into three components in order of increasing spin-spin relaxation time: a hard component at 160°C, a middle component at 160°C, and a soft component at 160°C, wherein the content of the hard component at 160°C is 10% or more and less than 60% of the total sum of the content of the hard component at 160°C, the content of the middle component at 160°C, and the content of the soft component at 160°C. The epoxy resin cured product is characterized in that the ratio of the spin-spin relaxation time of the hard component at 160°C to the spin-spin relaxation time of the hard component at 120°C is 1.30 or more, the spin-spin relaxation time of the hard component at 120°C is 10.0 microseconds or more and 22.0 microseconds or less, and the spin-spin relaxation time of the hard component at 160°C is 18.0 microseconds or more and 30.0 microseconds or less.

[0009] Furthermore, the present invention relates to an epoxy resin composition for obtaining the aforementioned epoxy resin cured product, characterized in that it contains an epoxy resin having a melt viscosity of 0.001 to 0.10 Pa·s at 150°C, and also contains a curing agent.

[0010] The epoxy resin described above preferably contains an epoxy resin component (A) represented by general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b). (Here, X is independently a divalent group containing a group represented by formula (2), (3a), or (3b) below. Z independently represents a glycidyl group or a group represented by formula (4a) or (4b) below. However, of the Z in formulas (1) and (2), at least one is a glycidyl group. n indicates the number of repetitions, and its average value is between 0 and 10.) (Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, where i is an integer from 1 to 4, but both 4-i and 3-i are greater than or equal to 0. ２ represents either a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. m1 indicates the number of repetitions, the average value of which is between 0.01 and 5. (Here, R ３ (where 'a' independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and 'j' is 1 to 4, and each may be the same group or different groups. 'Y' represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms, which may contain heteroatoms.) (Here, R ３ (Each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and q is 1 to 4, which may be the same group or different groups.) G represents a glycidyl group, and s1 is 0 or 1. Y represents a directly bonded alkylene group, an alkylene group which may have substituents, or an alkylene group which may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms which may contain heteroatoms. (Here, R ３ The atoms independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and these may be the same group or different groups. G represents a glycidyl group, where s2 is 1 or 2, s3 is an integer from 1 to 5, and s2 + s3 is an integer from 2 to 6. Y represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms, which may contain heteroatoms.

[0011] Furthermore, it is preferable that the curing agent is a polyvalent hydroxy resin represented by the following general formula (6), or an activated ester resin. (Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, where i is an integer from 1 to 4, but both 4-i and 3-i are greater than or equal to 0. ２１ (Each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. m3 indicates the number of repeats, with an average value of 0 to 5.)

[0012] The present invention also provides a prepreg, a laminated board or a printed wiring board using the above epoxy resin composition.

[0013] The present invention provides an epoxy resin cured product used as an insulating material, which cured product exhibits excellent low dielectric properties. The epoxy resin composition and the epoxy resin provided by the present invention are also excellent in low melt viscosity.

[0014] Fig.1 is an analysis example based on the slope of the magnetization intensity of a free induction decay curve obtained by pulsed NMR measurement measured by the Solid echo method. The vertical axis represents the magnetization intensity, and the horizontal axis represents the relaxation time T ２ . Fig.1 is obtained by waveform separation using an analytical formula representing the ratio of each component at relaxation times. The vertical axis represents the magnetization intensity, and the horizontal axis represents the relaxation time T ２ . Fig.2 is a GPC chart of the epoxy resin obtained in Example 1. Fig.3 is an IR chart of the epoxy resin obtained in Example 1. Fig.4 is a graph comparing the hard component ratios of Example 13 and Comparative Example 5.

[0015] Hereinafter, embodiments of the present invention will be described in detail.

[0016] The present invention relates to a cured epoxy resin product used as an insulating material. As will be described later, the cured epoxy resin product of the present invention is obtained by curing an epoxy resin composition, and the method for forming the cured product and the like are as described later. The cured epoxy resin product of the present invention is defined by the following measurements. That is, first, based on a free induction decay curve at 120° C. obtained by pulse NMR measured by the solid echo method (hereinafter, may be simply referred to as "pulse NMR" in the present application), the components contained in the cured product are separated into three components in order of shorter spin-spin relaxation time: a hard component at 120° C., a middle component at 120° C., and a soft component at 120° C. Similarly, based on a free induction decay curve at 160° C. obtained by pulse NMR measured by the solid echo method, the components contained in the cured product are separated into three components in order of shorter spin-spin relaxation time: a hard component at 160° C., a middle component at 160° C., and a soft component at 160° C. The reason why 120° C. and 160° C. are employed herein is that characteristic differences were observed in the following content and spin-spin relaxation time characteristics. When separated into such hard component, middle component and soft component at 120° C. or 160° C., the content of the hard component at 160° C. is 10% or more and less than 60% based on 100% in total of the content of the hard component at 160° C., the content of the middle component at 160° C., and the content of the soft component at 160° C.

[0017] Further, the ratio of the spin-spin relaxation time of the hard component at 160° C. to the spin-spin relaxation time of the hard component at 120° C. is 1.30 or more.

[0018] Further, the spin-spin relaxation time of the hard component at 120° C. is 10.0 microseconds (μs) or more and 22.0 microseconds (μs) or less, and furthermore, the spin-spin relaxation time of the hard component at 160° C. is 18.0 microseconds (μs) or more and 30.0 microseconds (μs) or less.

[0019] Because the epoxy resin cured product according to the present invention has the above-described structure, the epoxy equivalent can be increased compared to the case in which bisphenol-based epoxy resins are used, and as a result, the epoxy resin cured product can be made to have excellent low dielectric properties. Furthermore, since it has low melt viscosity equivalent to that of the case in which bisphenol-based epoxy resins are used, it also possesses low melt viscosity characteristics.

[0020] Here, pulsed NMR detects the response signal to a pulse and analyzes the sample. １ This method determines the magnetic relaxation time of the H nuclear, and a free induction decay curve is obtained as the response to the pulse. The obtained free induction decay curve is a superposition of free induction decay curves of multiple components with different spin-spin relaxation times (usually also called transverse relaxation times). By separating the waveform using the least squares method, the relaxation times and components of each component with different relaxation times can be detected. This method of separating and analyzing three components using pulse NMR is well known, and the components can be separated using known methods. In such pulse NMR, the three components described above—hard, middle, and soft—are obtained. The hard component is the component with a relatively short spin-spin relaxation time in the pulse NMR measurement, and is a hard component with relatively low molecular mobility. On the other hand, the soft component is the component with a relatively long spin-spin relaxation time in the pulse NMR, and is a soft component with relatively high molecular mobility. Furthermore, the middle component is defined as having a spin-spin relaxation time and molecular mobility intermediate between these hard and soft components. These hard, middle, and soft components can be appropriately adjusted according to the structure of the epoxy resin being blended, its blending ratio, and the characteristics and proportions of other raw materials. Furthermore, the free induction decay curve obtained by pulsed NMR measurement using the solid echo method can also be distinguished into hard, middle, and soft components based on the slope of the magnetization intensity of the curve, with the components corresponding to hard, middle, and soft components in descending order of slope. An example of such analysis based on the slope of the magnetization intensity of the curve is shown in Figure 1. In Figure 1, the vertical axis represents magnetization intensity, and the horizontal axis represents relaxation time T. ２represents. Further, FIG. 2 shows the curve of FIG. 1 subjected to waveform separation using an analytical expression representing magnetization intensity at relaxation time, that is, the ratio of each component at relaxation time. In FIG. 2, the vertical axis represents magnetization intensity, and the horizontal axis represents relaxation time T ２ .

[0021] As described above, when the components contained in the cured epoxy resin product according to the present invention are separated into three components, i.e., a hard component at 160°C, a middle component at 160°C, and a soft component at 160°C, in ascending order of spin-spin relaxation time, based on a free induction decay curve at 160°C obtained using pulsed NMR, the content of the hard component at 160°C is 10% or more and less than 60% based on 100% of the total of the content of the hard component at 160°C, the content of the middle component at 160°C, and the content of the soft component at 160°C. Therefore, for example, in the structure of an epoxy resin, the number of substituents that do not contribute to the crosslinking reaction of the epoxy resin but contribute to lowering the dielectric loss tangent can be increased, so it is presumed that low dielectric properties (low dielectric loss tangent) of the cured epoxy resin product can be achieved. In addition, the content of the inorganic filler can also be increased within the above range. Generally, inorganic fillers have a lower dielectric loss tangent than epoxy resins, so it is presumed that further low dielectric properties (low dielectric loss tangent) of the cured epoxy resin product can be achieved. Note that the sum of the content of the hard component at 160°C, the content of the middle component at 160°C, and the content of the soft component at 160°C is the content of the entire resin component of the cured epoxy resin product at 160°C. Here, the resin component usually includes the epoxy resin, curing agent, and curing accelerator described below, although it may vary depending on the composition.

[0022] In the cured epoxy resin product according to the present invention, based on 100% of the total of the content of the hard component at 160°C, the content of the middle component at 160°C, and the content of the soft component at 160°C, the content of the hard component at 160°C is preferably 50% or less, more preferably 45% or less, and still more preferably 40% or less.

[0023] In the epoxy resin cured product according to the present invention, the content of the hard component at 120°C is preferably 99% or less of the total 100% of the content of the hard component, the middle component, and the soft component at 120°C. More preferably, it is 98% or less. The lower limit of the content of the hard component at 120°C is not limited, but is preferably 70% or more, and more preferably 75% or more. The sum of the content of the hard component, the middle component, and the soft component at 120°C represents the total content of the resin components in the epoxy resin cured product at 120°C.

[0024] In the epoxy resin composition and epoxy resin cured product according to the present invention, the ratio of the spin-spin relaxation time of the hard component at 160°C to the spin-spin relaxation time of the hard component at 120°C is 1.30 or more. If this ratio is less than 1.30, it is thought that the number of substituents that contribute to low dielectric loss tangent in the epoxy resin structure will be reduced, and therefore sufficient low dielectric properties may not be obtained.

[0025] In the epoxy resin composition and epoxy resin cured product according to the present invention, the ratio of the spin-spin relaxation time of the hard component at 160°C to the spin-spin relaxation time of the hard component at 120°C is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.6 or less, and particularly preferably 1.5 or less.

[0026] In the epoxy resin cured product according to the present invention, the spin-spin relaxation time of the hard component at 160°C is set to 18.0 μs or more and 30.0 μs or less. If the spin-spin relaxation time of the hard component at 160°C is less than 18.0 μs, it is thought that there will be fewer substituents that contribute to low dielectric loss tangent, and therefore sufficient low dielectric properties may not be obtained. Also, if the spin-spin relaxation time of the hard component at 160°C exceeds 30.0 μs, it is thought that there will be many substituents that contribute to low dielectric properties (loss tangent), i.e., the weight-average molecular weight will be large, and therefore sufficient low melt viscosity properties may not be obtained. The spin-spin relaxation time of the hard component at 160°C is preferably 19.0 μs or more, more preferably 20.0 μs or more, preferably 30.0 μs or less, and more preferably 28.0 μs or less.

[0027] In the epoxy resin cured product according to the present invention, the spin-spin relaxation time of the hard component at 120°C is set to 10.0 μs or more and 22.0 μs or less. If the spin-spin relaxation time of the hard component at 120°C is less than 10.0 μs, it is thought that there will be fewer substituents that contribute to low dielectric loss tangent, and therefore sufficient low dielectric properties may not be obtained. Also, if the spin-spin relaxation time of the hard component at 120°C exceeds 22.0 μs, it is thought that there will be many substituents that contribute to low dielectric properties (loss tangent), i.e., the weight-average molecular weight will be large, and therefore sufficient low melt viscosity properties may not be obtained. The spin-spin relaxation time of the hard component at 120°C is preferably 13.0 μs or more, more preferably 14.0 μs or more, preferably 21.0 μs or less, and more preferably 20.0 μs or less.

[0028] The content of hard, middle, and soft components at 120°C, the content of hard, middle, and soft components at 160°C, and the spin-spin relaxation time of the hard component at 120°C and the spin-spin relaxation time of the hard component at 160°C can be specifically determined by the method described in the examples.

[0029] The following describes in detail each component used in the resin material for obtaining the epoxy resin composition and epoxy resin cured product according to the present invention.

[0030] The epoxy resin cured product according to the present invention is a cured product of an epoxy resin composition and contains an epoxy resin. The epoxy resin is an epoxy resin comprising an epoxy resin component (A) represented by the following general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b).

[0031]

[0032] Here, X in general formula (1) is independently a divalent group containing a group represented by the following formulas (2), (3a), or (3b). Preferably, at least one of X is the group represented by formula (2). Z independently represents a glycidyl group or a group represented by the following formulas (4a) or (4b). However, of Z in formulas (1) and (2), at least one is a glycidyl group. n indicates the number of repetitions, and its average value is preferably a number from 0 to 10, more preferably from 0 to 5. A more preferable average value of n is 0.01 to 3.0.

[0033] Here, epoxy resin component (B) includes not only epoxidized phenol compounds having a specific structure represented by general formula (7a) or (7b) used as raw materials, but also epoxidized polyvalent hydroxy resins represented by general formula (6) where m3 is 0 (zero) (m3=0). This is because m3=0 in the epoxidized polyvalent hydroxy resin represented by general formula (6) is equivalent to general formula (5b), and is therefore included in epoxy resin component (B).

[0034] In general formula (5a) or (5b), R ３ ¹ and ¹ independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and these may be the same group or different groups. G represents a glycidyl group, s² is 1 or 2, s³ is an integer from 1 to 5, and s² + s³ is an integer from 2 to 6. Y represents an alkylene group that may have a direct bond, a substituent, or an aromatic group. Here, the substituent is a hydrocarbon group having 1 to 10 carbon atoms, which may contain a heteroatom. For example, R in formula (2) described later is an example. １The groups exemplified above can be cited. In addition, groups in which a heteroatom is included in some of the groups exemplified below can be cited. Aromatic groups can be monovalent or divalent aromatic groups.

[0035]

[0036] In equation (2), R １ The substituent represents a hydrocarbon group having 1 to 10 carbon atoms, and is preferably an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 8 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, or an allyl group. The alkyl group having 1 to 10 carbon atoms can be linear, branched, or cyclic, and is not limited to, but includes, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, a hexyl group, a cyclohexyl group, a methylcyclohexyl group, etc. The aryl group having 6 to 8 carbon atoms can be a phenyl group, a tolyl group, a xylyl group, an ethylphenyl group, etc., but is not limited to these. The aralkyl group having 7 to 8 carbon atoms can be a benzyl group, an α-methylbenzyl group, etc., but is not limited to these. Among these substituents, the phenyl group and the methyl group are preferred from the viewpoint of ease of availability and reactivity when cured, and the methyl group is particularly preferred. １ The substitution position may be ortho, meta, or para, but the ortho position is preferred.

[0037] R ２ R represents a hydrogen atom or the aforementioned hydrocarbon group having 1 to 10 carbon atoms. ２ R is a substituent. １ Unlike the above, it does not necessarily indicate only substituents, but also hydrogen atoms.

[0038] i is substituent R １ The number is an integer between 1 and 4, preferably 1 or 2, more preferably 2. In this case, it is preferable that 3-i and 4-i are 0 or greater.

[0039] The value of Z in equation (2) is the same as the value of Z in equation (1).

[0040] m1 represents the number of repetitions, and its average value (number mean) is between 0.01 and 5, preferably between 0.01 and 3.0, more preferably between 0.01 and 2.5, and even more preferably between 0.01 and 2.0.

[0041] In equations (3a) and (3b), R ３ R independently represents a hydrogen atom or the aforementioned hydrocarbon group having 1 to 10 carbon atoms. j is 1 to 4, and each may be the same group or different groups. As for hydrocarbon groups having 1 to 10 carbon atoms, R １ Similar examples are given. ３ From the viewpoint of ease of availability and heat resistance of the cured product, hydrogen atoms, methyl groups, ethyl groups, and dicyclopentadiene groups are preferred, and hydrogen atoms, methyl groups, or the aforementioned dicyclopentadiene groups are particularly preferred. j is substituent R ３ The number is 1 to 4, preferably 1 to 3. Y represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituent is a hydrocarbon group having 1 to 10 carbon atoms, which may contain heteroatoms.

[0042]

[0043] In equations (4a) and (4b), R ３ R is in equations (3a) and (3b). ３ It is similar to the above. q is substituent R ３ The number is 1 to 4, preferably 1 to 3. s1 is 0 or 1. Y represents a directly bonded alkylene group, an alkylene group which may have substituents, or an alkylene group which may have aromatic groups. The substituent is a hydrocarbon group having 1 to 10 carbon atoms which may contain heteroatoms.

[0044] Furthermore, epoxy resins are preferably obtained by epoxidizing a mixture containing a polyvalent hydroxy resin represented by the following general formula (6) and a phenol compound represented by either the following general formula (7a) or formula (7b). Here, as can be seen from the descriptions of epoxy resin component (A) and epoxy resin component (B) above, preferably, if m3 in formula (6) is 0.01 or more, X in formula (1) will have the structure shown in formula (2), and epoxy resin component (A) can be obtained by epoxidizing using such a polyvalent hydroxy resin. Also, epoxy resin component (B) can be obtained by epoxidizing a polyvalent hydroxy resin in which m3 in formula (6) is 0, or a phenol compound having a specific structure represented by formula (7a) or (7b).

[0045] In this case, the epoxy resin component (A) may have a structure in which the Z group is represented by formula (4a) or formula (4b), and this is thought to be due to the following reaction mechanism. Specifically, since two types of raw materials, the polyvalent hydroxy resin and the phenol compound, are mixed and reacted with epichlorohydrin (epoxidized), it is thought that during the reaction, the hydroxyl group of the unepoxidized phenol compound has a proton abstracted by the base and reacts with the previously epoxidized polyvalent hydroxy resin, thereby acquiring the structure of formula (4a) or (4b) as the Z group.

[0046]

[0047] In general formula (6), R １ i is R in equation (2) １ These are synonymous with i, respectively. ２１ represents independently a hydrogen atom or the hydrocarbon group having 1 to 10 carbon atoms. m3 indicates the number of repetitions, and its average value is between 0 and 5. m3 is preferably between 0.01 and 3.0, more preferably between 0.01 and 2.5, and even more preferably between 0.01 and 2.0.

[0048] In equation (7a), R ３ R is in equations (3a) and (3b). ３It is similar to the above. q1 is the number of hydroxyl groups, which is 1 or 2, and q2 is the substituent R. ３ The number is an integer from 1 to 4, preferably from 1 to 3, and q1 + q2 is an integer from 2 to 6, preferably from 2 to 4. Y represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituent is a hydrocarbon group having 1 to 10 carbon atoms, which may contain heteroatoms. In formula (7b), q3 is the number of hydroxyl groups, which is 1 or 2, and q4 is substituent R ３ The number is an integer between 1 and 5, preferably between 1 and 3, and q3 + q4 is an integer between 2 and 6, preferably between 2 and 4.

[0049] Polyvalent hydroxy resins represented by general formula (6) can be produced by known methods. For example, they can be obtained by the production method disclosed in Patent Document 4.

[0050] The aforementioned R １ , R ２ , R ３ , R ２１ The basis of this can be confirmed using mass spectrometry and FT-IR measurement. When using mass spectrometry, electrospray mass spectrometry (ESI-MS) or field desorption (FD-MS) can be used.

[0051] The phenolic hydroxyl group equivalent (g / eq.) of the polyvalent hydroxy resin represented by general formula (6) is preferably 160 to 400, more preferably 180 to 380, and even more preferably 200 to 360.

[0052] The phenolic hydroxyl group equivalent (g / eq.) of phenol compounds having the specific structures represented by formulas (7a) and (7b) is preferably 80 to 260.

[0053] Examples of phenol compounds having a specific structure represented by formula (7a) or formula (7b) include cresol, ethylphenol, propylphenol, isopropylphenol, n-butylphenol, t-butylphenol, hexylphenol, cyclohexylphenol, phenylphenol, tolylphenol, benzylphenol, α-methylbenzylphenol, allylphenol, dimethylphenol, t-butyl-dimethylphenol, diethylphenol, dipropylphenol, diisopropylphenol, di(n-butyl)phenol, di(t-butyl)phenol, dihexylphenol, dicyclohexylphenol, and diphenol. Examples include nylphenol, ditylphenol, dibenzylphenol, bis(α-methylbenzyl)phenol, methylethylphenol, methylpropylphenol, methylisopropylphenol, methylbutylphenol, methyl-t-butylphenol, methylallylphenol, tolylphenylphenol, t-butylcatechol, t-butylresorcinol, t-butylhydroquinone, bisphenol F, bisphenol A, bisphenol C, bisphenol M, bisphenol P, tetramethylbisphenol F, tetramethylbisphenol A, and 3,3',5,5'-tetramethylbiphenyl-4,4'-diol. From the viewpoint of ease of availability and reactivity when cured, t-butylcatechol, bisphenol F, bisphenol A, bisphenol C, bisphenol M, bisphenol P, tetramethylbisphenol F, tetramethylbisphenol A, and 3,3',5,5'-tetramethylbiphenyl-4,4'-diol are preferred.

[0054] As a raw material for epoxy resin, the above-mentioned polyvalent hydroxy resin and phenol compounds other than the above-mentioned phenol compounds can be used in combination, as long as they do not inhibit the effect of the epoxy resin. The phenol compounds that can be used in combination are preferably monovalent or divalent compounds. The amount that can be used in combination is preferably in the range of 10% to 90% by mass relative to the total amount of the phenol compound component.

[0055] The epoxy resin comprises an epoxy resin component (A) represented by general formula (1) and an epoxy resin component (B) represented by general formula (5a) or (5b). This epoxy resin can be suitably obtained by reacting an epihalohydrin such as epichlorohydrin with a mixture of a polyvalent hydroxy resin represented by general formula (6) and a phenol compound represented by general formulas (7a) and (7b). This epoxidation reaction is carried out according to conventionally known methods.

[0056] One method of epoxidization is to prepare, for example, the above-mentioned polyvalent hydroxy resin and phenol compound as raw materials, along with an excess molar amount of epihalohydrin relative to the total hydroxyl groups of the polyvalent hydroxy resin and phenol compound. To this mixture of reaction materials, an alkali metal hydroxide such as sodium hydroxide is added as a solid or concentrated aqueous solution, and the mixture is reacted at a reaction temperature of 30 to 120°C for 0.5 to 10 hours to obtain epoxy resin. Alternatively, epoxy resin can also be obtained by adding a quaternary ammonium salt such as tetraethylammonium chloride as a catalyst to the reaction material mixture, reacting at a temperature of 50 to 150°C for 1 to 5 hours to obtain a polyhalohydrin ether, and then adding an alkali metal hydroxide such as sodium hydroxide as a solid or concentrated aqueous solution to the ether and reacting at a temperature of 30 to 120°C for 1 to 10 hours.

[0057] In the above reaction, it is preferable to use 10 to 300 parts by mass of the phenol compound per 100 parts by mass of the polyvalent hydroxy resin, and more preferably 10 to 250 parts by mass of the phenol compound per 100 parts by mass of the polyvalent hydroxy resin. Furthermore, the amount of epihalohydrin used is 1 to 20 times the molars of the total hydroxyl groups of the mixture of polyvalent hydroxy resin and phenol compound, and preferably 2 to 8 times the molars. Furthermore, the amount of alkali metal hydroxide used is preferably 0.85 to 1.15 times the molars of the total hydroxyl groups of the mixture of polyvalent hydroxy resin and phenol compound.

[0058] Since the epoxy resin obtained from these reactions contains unreacted epihalohydrins and alkali metal halides, the unreacted epihalohydrins can be removed from the reaction mixture by evaporation, and the alkali metal halides can be removed by methods such as extraction with water or filtration to obtain the desired epoxy resin.

[0059] The epoxy equivalent (g / eq.) of the epoxy resin is preferably 160 to 400, more preferably 170 to 360, and even more preferably 180 to 340. The melt viscosity at 150°C is preferably 0.001 to 0.10 Pa·s, and more preferably 0.001 to 0.05 Pa·s. The weight-average molecular weight (Mw) is preferably 200 to 2000, more preferably 300 to 1000, and the number-average molecular weight (Mn) is preferably 100 to 1000, more preferably 150 to 800. The total chlorine content is preferably 2000 ppm or less, and even more preferably 1500 ppm or less.

[0060] The epoxy resin composition and the epoxy resin cured product contain an epoxy resin and a curing agent, and it is preferable that the epoxy resin contains the aforementioned epoxy resin. In this embodiment, part or all of the epoxy resin is the aforementioned epoxy resin.

[0061] Preferably, the epoxy resin is 30% by mass or more of the epoxy resin described above. More preferably, it should be 50% by mass or more, and even more preferably 70% by mass or more. If the amount is less than this, the dielectric properties may deteriorate.

[0062] As the epoxy resin used in the epoxy resin composition and epoxy resin cured product of the present invention, one or more types of epoxy resins may be used in combination with the aforementioned epoxy resin, as needed. The amount that can be used in combination is preferably less than 50% by mass, more preferably less than 10% by mass, relative to the total amount of epoxy resin.

[0063] Any conventional epoxy resin that has two or more epoxy groups in its molecule can be used in combination with this product.For example, trifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, tetramethylbisphenol F type epoxy resin, hydroquinone type epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, bisphenol fluorene type epoxy resin, bisphenol S type epoxy resin, bisthioether type epoxy resin, resorcinol type epoxy resin, biphenyl aralkylphenol type epoxy resin, naphthalenediol type epoxy resin, phenol novolac type epoxy resin, aromatic modified phenol novolac type epoxy resin, cresol novolac type epoxy resin, alkyl novolac type epoxy resin, bisphenol novolac type epoxy resin, binaphthol type epoxy resin, naphthol novolac type epoxy resin, β-naphthol aralkyl type epoxy resin, dinaphthol aralkyl type epoxy resin, α-naphthol aralkyl type epoxy resin, trisphenylmethane type epoxy resin, and tetrafunctional epoxy resins such as tetrakisphenylethane type epoxy resin. Other examples of epoxy resins include, but are not limited to, dicyclopentadiene-type epoxy resins, polyhydric alcohol polyglycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether; alkylene glycol-type epoxy resins such as propylene glycol diglycidyl ether; aliphatic cyclic epoxy resins such as cyclohexanedimethanol diglycidyl ether; glycidyl esters such as dimer acid polyglycidyl esters; glycidylamine-type epoxy resins such as phenyl diglycidylamine, tol diglycidylamine, diaminodiphenylmethane tetraglycidylamine, and aminophenol-type epoxy resins; alicyclic epoxy resins such as Celoxide 2021P (manufactured by Daicel Corporation); phosphorus-containing epoxy resins; bromine-containing epoxy resins; urethane-modified epoxy resins; and oxazolidone ring-containing epoxy resins. Furthermore, these epoxy resins may be used individually or in combination of two or more types.From the viewpoint of availability, it is even more preferable to use epoxy resins represented by the following general formula (8), dicyclopentadiene type epoxy resins other than those of the present invention, naphthalenediol type epoxy resins, phenol novolac type epoxy resins, aromatic modified phenol novolac type epoxy resins, cresol novolac type epoxy resins, α-naphthol aralkyl type epoxy resins, phosphorus-containing epoxy resins, and oxazolidone ring-containing epoxy resins.

[0064] In general formula (8), R ７ is independently a hydrocarbon group having 1 to 10 carbon atoms, such as alkyl groups like methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-hexyl, and cyclohexyl, and may be the same or different from each other. X is a divalent organic group, such as alkylene groups like methylene, ethylene, isopropylidene, isobutylene, and hexafluoroisopropylidene, or -CO-, -O-, -S-, and -SO ２ -, -S-S-, or an aralkylene group represented by formula (8a). In formula (8a), R ８ is independently a hydrogen atom or a hydrocarbon group having 1 or more carbon atoms, for example, a methyl group, and may be the same or different from each other. Ar is a benzene ring or a naphthalene ring, and these benzene rings or naphthalene rings may have substituents of an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 11 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms.

[0065] As curing agents, various phenolic resins, acid anhydrides, amines, cyanate esters, activated esters, hydrazides, acidic polyesters, aromatic cyanates, and other agents commonly used as curing agents for epoxy resins can be used. A polyvalent hydroxy resin represented by general formula (6) can also be used, as can an activated ester resin esterified using a known esterifying agent and a polyvalent hydroxy resin represented by formula (6) as a raw material. The esterifying agent is not limited, but carboxylic acid compounds and halides of carboxylic acid compounds can be used. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid, which will be described later. These curing agents may be used alone or in combination of two or more types.

[0066] In the epoxy resin composition and epoxy resin cured product of the present invention, the molar ratio of active hydrogen groups of the curing agent to 1 mole of epoxy groups of the total epoxy resin is preferably 0.2 to 1.5 moles, more preferably 0.3 to 1.4 moles, even more preferably 0.5 to 1.3 moles, and particularly preferably 0.8 to 1.2 moles. If the ratio falls outside this range, curing may be incomplete and good cured properties may not be obtained. For example, when using a phenolic resin-based curing agent or an amine-based curing agent, the active hydrogen groups are blended in approximately equimolar amounts with respect to the epoxy groups. When using an acid anhydride-based curing agent, the acid anhydride groups are blended in preferably 0.5 to 1.2 moles, more preferably 0.6 to 1.0 moles, per mole of epoxy groups. When using the phenolic resin of the present invention alone as a curing agent, it is desirable to use it in the range of 0.9 to 1.1 moles per mole of epoxy resin.

[0067] In this application, an active hydrogen group refers to a functional group having an active hydrogen that reacts with an epoxy group (including functional groups having latent active hydrogen that generates active hydrogen by hydrolysis, etc., and functional groups that exhibit equivalent curing effects). Specifically, examples include acid anhydride groups, carboxyl groups, amino groups, and phenolic hydroxyl groups. Regarding active hydrogen groups, 1 mole of a carboxyl group or phenolic hydroxyl group is 1 mole of an amino group (NH ２) is calculated as 2 moles. Furthermore, if the active hydrogen group is not clear, the active hydrogen equivalent can be determined by measurement. For example, by reacting a monoepoxy resin such as phenylglycidyl ether with a known epoxy equivalent with a curing agent whose active hydrogen equivalent is unknown, and measuring the amount of monoepoxy resin consumed, the active hydrogen equivalent of the curing agent used can be determined.

[0068] Specific examples of phenolic resin curing agents that can be used in the epoxy resin composition and epoxy resin cured product of the present invention include bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, tetramethylbisphenol Z, tetrabromobisphenol A, dihydroxydiphenyl sulfide, 4,Bisphenols such as 4'-thiobis(3-methyl-6-t-butylphenol), dihydroxybenzenes such as catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, mono-t-butylhydroquinone, di-t-butylhydroquinone, and hydroxynaphthalenes such as dihydroxynaphthalene, dihydroxymethylnaphthalene, dihydroxymethylnaphthalene, and trihydroxynaphthalene, and Phosphorus-containing phenol curing agents such as LC-950PM60 (manufactured by Shin-AT&C), phenol novolac resins such as Showol BRG-555 (manufactured by Aica Kogyo Co., Ltd.), cresol novolac resins such as DC-5 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), triazine skeleton-containing phenol resins, aromatically modified phenol novolac resins, bisphenol A novolac resins, and trishydroxyphenylmethane-type novolac resins such as Resitopp TPM-100 (manufactured by Gun-ei Chemical Industry Co., Ltd.) Examples include phenol compounds known as novolac phenol resins, such as naphthol novolac resins, phenols such as naphthol novolac resins, condensates of naphthols and / or bisphenols with aldehydes, phenols such as SN-160, SN-395, and SN-485 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), condensates of phenols and / or naphthols and / or bisphenols with xylylene glycol, condensates of phenols and / or naphthols with isopropenylacetophenone, reaction products of phenols and / or naphthols and / or bisphenols with dicyclopentadiene, reaction products of phenols and / or naphthols and / or bisphenols with divinylbenzene, reaction products of phenols and / or naphthols and / or bisphenols with terpenes, and condensates of phenols and / or naphthols and / or bisphenols with biphenyl crosslinking agents, polybutadiene-modified phenol resins, and phenol resins having spiro rings. From the viewpoint of availability, phenol novolac resins, dicyclopentadienephenol resins, trishydroxyphenylmethane-type novolac resins, aromatically modified phenol novolac resins, etc., are preferred.

[0069] Novolac phenol resin can be obtained from phenols and crosslinking agents. Examples of phenols include phenol, cresol, xylenol, butylphenol, amylphenol, nonylphenol, butylmethylphenol, trimethylphenol, and phenylphenol. Examples of naphthols include 1-naphthol and 2-naphthol. In addition, bisphenols, which were listed as phenol resin curing agents above, can be used. Examples of aldehydes used as crosslinking agents include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, benzaldehyde, chloraldehyde, bromaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipinealdehyde, pimelinaldehyde, sebacinaldehyde, acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, and hydroxybenzaldehyde. Examples of biphenyl-based crosslinking agents include bis(methylol)biphenyl, bis(methoxymethyl)biphenyl, bis(ethoxymethyl)biphenyl, and bis(chloromethyl)biphenyl.

[0070] Examples of acid anhydride-based curing agents include maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic acid anhydride, 1,2,3,6-tetrahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, methylnadic anhydride, copolymers of styrene monomer and maleic anhydride, copolymers of indenes and maleic anhydride, and the like.

[0071] Examples of amine-based curing agents include, specifically, diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, polyetheramines, biguanide compounds, aromatic amines such as dicyandiamide and anisidine, and amine compounds such as polyamidoamines, which are condensates of acids such as dimer acids and polyamines.

[0072] The cyanate ester compound is not particularly limited as long as it is a compound having two or more cyanate groups (cyanate ester groups) in one molecule. Examples include novolac-type cyanate ester curing agents such as phenol novolac type and alkylphenol novolac type, naphthol aralkyl-type cyanate ester curing agents, biphenylalkyl-type cyanate ester curing agents, dicyclopentadiene-type cyanate ester curing agents, bisphenol-type cyanate ester curing agents such as bisphenol A type, bisphenol F type, bisphenol E type, tetramethylbisphenol F type, and bisphenol S type, and prepolymers in which these are partially triazined. Specific examples of cyanate ester-based curing agents include, for example, bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate), bis(3-methyl-4-cyanatephenyl)methane, bis(3-ethyl-4-cyanatephenyl)methane, bis(4-cyanatephenyl)-1,1-ethane, 4,4-dicyanate-diphenyl, 2,2-bis(4-cyanatephenyl)-1,1,1,3,3,3-hexafluoropropane, 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenyl Examples include difunctional cyanate resins such as methane, bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl) thioether, and bis(4-cyanatephenyl) ether; cyanate esters of trivalent phenols such as tris(4-cyanatephenyl)-1,1,1-ethane and bis(3,5-dimethyl-4-cyanatephenyl)-4-cyanatephenyl-1,1,1-ethane; polyfunctional cyanate resins derived from phenol novolacs, cresol novolacs, and phenol resins containing dicyclopentadiene structures; and prepolymers in which these cyanate resins are partially triazined. One or more of these can be used.

[0073] While there are no particular restrictions on the active ester curing agent, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. Particularly from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and / or a naphthol compound is more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyldiphenol, dicyclopentadienphenol resin (a raw material for the epoxy resin mentioned above), phenol novolac, etc. One or more active ester curing agents can be used. As for the active ester curing agent, specifically, active ester curing agents containing a dicyclopentadienyldiphenol structure, active ester curing agents containing a naphthalene structure, active ester curing agents that are acetylated phenol novolacs, and active ester curing agents that are benzoylated phenol novolacs are preferred, and among these, active ester curing agents containing a dicyclopentadienyldiphenol structure, which is a raw material for epoxy resin as described above, are more preferred in that they are excellent in improving peel strength.

[0074] Other curing agents include, specifically, phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 1-cyanoethyl-2-methylimidazole, imidazole salts which are salts of imidazoles with trimellitic acid, isocyanuric acid, or boron, etc., quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, salts of diazabicyclo compounds with phenols or phenol novolac resins, etc., complex compounds of boron trifluoride with amines or ether compounds, aromatic phosphonium, or iodonium salts.

[0075] Curing accelerators may be used in epoxy resin compositions and epoxy resin cured products as needed. Examples of usable curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 4-dimethylaminopyridine, 2-(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)undecene-7; phosphines such as triphenylphosphine, tricyclohexylphosphine, and triphenylphosphinetriphenylborane; and metal compounds such as tin octylate. When using a curing accelerator, the amount used is preferably 0.02 to 5 parts by mass per 100 parts by mass of the epoxy resin component in the epoxy resin composition of the present invention. By using a curing accelerator, the curing temperature can be lowered and the curing time can be shortened.

[0076] Organic solvents or reactive diluents can be used to adjust the viscosity of epoxy resin compositions and cured epoxy resin products.

[0077] Examples of organic solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, ethers such as ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, and triethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, alcohols such as methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol, butyl diglycol, and pine oil, and butyl acetate. Examples of such substances include, but are not limited to, acetate esters such as methoxybutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and benzyl alcohol acetate; benzoic acid esters such as methyl benzoate and ethyl benzoate; cellosolves such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; carbitols such as methyl carbitol, ethyl carbitol, and butyl carbitol; aromatic hydrocarbons such as benzene, toluene, and xylene; and dimethyl sulfoxide, acetonitrile, and N-methylpyrrolidone.

[0078] Examples of reactive diluents include, but are not limited to, monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and tolyl glycidyl ether, as well as monofunctional glycidyl esters such as neodecanoic acid glycidyl ester.

[0079] These organic solvents or reactive diluents, either individually or in combination, are preferably used in epoxy resin compositions at a concentration of 90% by mass or less as non-volatile content, with the appropriate type and amount being selected as appropriate depending on the application. For example, in printed circuit board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, or 1-methoxy-2-propanol, are preferred, and the amount used in the epoxy resin composition is preferably 40 to 80% by mass as non-volatile content. In adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc., are preferred, and the amount used is preferably 30 to 60% by mass as non-volatile content.

[0080] Epoxy resin compositions and epoxy resin cured products may contain other thermosetting resins or thermoplastic resins to the extent that their properties are not impaired. Examples include, but are not limited to, phenolic resins, benzoxazine resins, bismaleimide resins, bismaleimide triazine resins, acrylic resins, petroleum resins, indene resins, coumarone indene resins, phenoxy resins, polyurethane resins, polyester resins, polyamide resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyethersulfone resins, polysulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, polyvinyl formal resins, polysiloxane compounds, and alkylene resins containing reactive functional groups such as hydroxyl group-containing polybutadiene.

[0081] Various known flame retardants can be used in epoxy resin compositions and epoxy resin cured products to improve the flame retardancy of the resulting cured products. Examples of usable flame retardants include halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organometallic salt-based flame retardants. From an environmental standpoint, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used individually or in combination of two or more types.

[0082] Phosphorus-based flame retardants can be either inorganic phosphorus compounds or organophosphorus compounds. Examples of inorganic phosphorus compounds include ammonium phosphates such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, and polyammonium phosphate, as well as inorganic nitrogen-containing phosphorus compounds such as phosphate amides. Examples of organophosphorus compounds include aliphatic phosphate esters, phosphate ester compounds, condensed phosphate esters such as PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.), phosphazenes, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phospholane compounds, and organic nitrogen-containing phosphorus compounds, as well as metal salts of phosphinic acid, cyclic organophosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydrooxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydrooxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and derivatives obtained by reacting these with compounds such as epoxy resins and phenolic resins, such as phosphorus-containing epoxy resins and phosphorus-containing curing agents.

[0083] The amount of flame retardant added is appropriately selected depending on the type of phosphorus-based flame retardant, the components of the epoxy resin composition, and the desired degree of flame retardancy. For example, the phosphorus content in the organic components (excluding organic solvents) of the epoxy resin composition is preferably 0.2 to 4% by mass, more preferably 0.4 to 3.5% by mass, and even more preferably 0.6 to 3% by mass. If the phosphorus content is too low, it may be difficult to ensure flame retardancy, and if it is too high, it may adversely affect the heat resistance. When using a phosphorus-based flame retardant, a flame retardant aid such as magnesium hydroxide may also be used in combination.

[0084] Fillers may be used in epoxy resin compositions and epoxy resin cured products as needed. Specifically, examples include fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, boehmite, magnesium hydroxide, talc, mica, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium carbonate, barium sulfate, boron nitride, carbon, carbon fiber, glass fiber, alumina fiber, silica-alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, ceramic fiber, fine particle rubber, silicone rubber, thermoplastic elastomer, carbon black, and pigments. Generally, the reason for using fillers is to improve impact resistance. In addition, when metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide are used, they act as flame retardant aids, improving flame retardancy. The amount of these fillers added to the total epoxy resin composition is preferably 1 to 150% by mass, and more preferably 10 to 70% by mass. If the amount added is too high, the adhesion required for laminate applications may decrease, and the cured product may become brittle, resulting in insufficient mechanical properties. Furthermore, if the amount of filler used is too small, the intended effects of the filler, such as improved impact resistance of the cured product, may not be realized.

[0085] When epoxy resin compositions are used to form plate-shaped substrates, fibrous materials are preferred as fillers in terms of dimensional stability and bending strength. More preferably, glass fiber substrates are made by weaving glass fibers into a mesh.

[0086] The epoxy resin composition and the cured epoxy resin product may further contain various additives as needed, such as silane coupling agents, antioxidants, mold release agents, defoaming agents, emulsifiers, thixotropy-inducing agents, smoothing agents, flame retardants, and pigments. The amount of these additives added is preferably in the range of 0.01 to 20% by mass relative to the epoxy resin composition.

[0087] Epoxy resin compositions and cured epoxy resins can be used to create prepregs for printed circuit boards and the like by impregnating them into fibrous substrates. Fibrous substrates can be inorganic fibers such as glass, or woven or nonwoven fabrics of organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, or aromatic polyamide resin, but are not limited to these. There are no particular limitations on the method for producing a prepreg from an epoxy resin composition. For example, the epoxy resin composition can be immersed in a resin varnish prepared by adjusting the viscosity with an organic solvent, impregnated, and then heated and dried to partially cure (B-stage) the resin component. For example, it can be heated and dried at 100 to 200°C for 1 to 40 minutes. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass.

[0088] Furthermore, while the curing method for laminates commonly used in the manufacture of printed circuit boards can be used to cure the prepreg, it is not limited to this method. For example, when forming a laminate using a prepreg, one or more prepregs are stacked, metal foil is placed on one or both sides to form a laminate, and this laminate is heated and pressurized to integrate the layers. Here, single, alloy, or composite metal foils of copper, aluminum, brass, nickel, etc., can be used as the metal foil. Then, the prepreg is cured by pressurizing and heating the created laminate to obtain a laminate. At that time, it is preferable to set the heating temperature to 160 to 220°C, the pressurizing pressure to 5 to 50 MPa, and the heating and pressurizing time to 40 to 240 minutes, thereby obtaining the desired cured product. If the heating temperature is too low, the curing reaction will not proceed sufficiently, and if it is too high, there is a risk that the epoxy resin composition will begin to decompose. Also, if the pressurizing pressure is too low, air bubbles may remain inside the resulting laminate, which may reduce its electrical properties, and if it is too high, the resin may flow before curing, which may prevent obtaining a cured product of the desired thickness. Furthermore, if the heating and pressurizing time is too short, the curing reaction may not proceed sufficiently, and if it is too long, thermal decomposition of the epoxy resin composition in the prepreg may occur, which is undesirable.

[0089] Epoxy resin compositions can be cured in the same manner as known epoxy resin compositions to obtain a cured epoxy resin product. Methods for obtaining the cured product can be the same as those for known epoxy resin compositions, and methods such as casting, injection, potting, dipping, drip coating, transfer molding, compression molding, etc., or lamination of resin sheets, resin-coated copper foil, prepregs, etc., followed by heating, pressing, and curing to form laminates are preferably used. The curing temperature is typically 100 to 300°C, and the curing time is typically 1 to 5 hours.

[0090] In particular, in the present invention, the curing method and conditions are not limited as long as the aforementioned properties of the epoxy resin cured product measured by pulsed NMR using the Solid echo method described above can be obtained or evaluated. However, it is preferable to obtain a cured product that is capable of being evaluated by such measurement, and it is even more preferable to use a completely cured product. The heating conditions at that time are not limited, but are preferably 100 to 220°C, and more preferably 130 to 220°C. The pressurizing conditions at that time are also not limited, but in the present invention, conditions that can be used to obtain samples or products such as molded plates necessary for evaluating dielectric properties can be appropriately adopted.

[0091] The epoxy resin composition and epoxy resin cured product of the present invention can take the form of laminates, molded products, adhesives, coatings, films, and the like.

[0092] An epoxy resin composition containing an epoxy resin with excellent low melt viscosity was prepared, and laminates and cured products were evaluated by heat curing. As a result, it was possible to provide an epoxy resin cured product that exhibits excellent low dielectric properties in the cured product. Specifically, the dielectric properties can be expressed as follows: relative permittivity of 3.10 or less, more preferably 3.00 or less, even more preferably 2.90 or less, dielectric loss tangent of 0.0055 or less, and more preferably 0.0050 or less.

[0093] The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, "parts" refers to parts by mass, "%" refers to mass percent, and "ppm" refers to mass ppm. The measurements were performed using the following methods.

[0094] (1) Hydroxyl group equivalent: Measurement was performed in accordance with JIS K0070 standard, and the unit was expressed as "g / eq.". Unless otherwise specified, the hydroxyl group equivalent of phenol resin refers to the phenolic hydroxyl group equivalent.

[0095] (2) Epoxy equivalent: Measurement was performed in accordance with JIS K7236 standard, and the unit was expressed as "g / eq." Specifically, an automatic potentiometric titrator (Hiruma Sangyo Co., Ltd., COM-1600ST) was used, chloroform was used as the solvent, tetraethylammonium brominated acetate solution was added, and titration was performed with 0.1 mol / L perchloric acid-acetic acid solution.

[0096] (3) Ester equivalent: Measurement was performed in accordance with JIS K0070 standard, and the unit was expressed in "g / eq.". The ester equivalent can be calculated using the following formula (9). Ester equivalent = saponification value - acid value Formula (9) (3-1) Acid value: Using an automatic potentiometric titrator (manufactured by Hiranuma Sangyo Co., Ltd., COM-1600ST), the sample was dissolved in any solvent and titrated with a 0.1 mol / L potassium hydroxide-ethanol aqueous solution. (3-2) Saponification value: Using an automatic potentiometric titrator (manufactured by Hiranuma Sangyo Co., Ltd., COM-1600ST), the sample was dissolved in any solvent, a 0.5 mol / L potassium hydroxide-ethanol aqueous solution was added, the mixture was gently heated and cooled to room temperature. Ethanol was added and the mixture was titrated with a 0.5 mol / L hydrochloric acid aqueous solution.

[0097] (4) Melt viscosity: The melt viscosity at 150°C was measured using an ICI viscometer (Toa Kogyo Co., Ltd., CV-1S).

[0098] (5) Relative permittivity and dielectric loss tangent: These were measured in accordance with IPC-TM-650 2.5.5.15. Specifically, the sample was dried in an oven set to 105°C for 2 hours, cooled in a desiccator, and then evaluated by determining the relative permittivity and dielectric loss tangent at a frequency of 10 GHz using the Split Post Dielectric Resonator method with a network analyzer manufactured by AGILENT Technologies.

[0099] (6) GPC (Gel Permeation Chromatography) Measurement: A main unit (Tosoh Corporation, HLC-8220GPC) with columns (Tosoh Corporation, TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL) in series was used, and the column temperature was set to 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 mL / min, and a differential refractive index detector was used. For the measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF, filtered through a microfilter, and 50 μL of the result was used. Data processing was performed using Tosoh Corporation's GPC-8020 Model II version 6.00.

[0100] (7) IR: Using a Fourier transform infrared spectrophotometer (Perkin Elmer Precisly, Spectrum One FT-IR Spectrometer 1760X), a diamond ATR was used to coat the sample dissolved in toluene onto the ATR, dry it, and then measure the wavenumber from 650 to 4000 cm. －１ The absorbance was measured.

[0101] (8) Pulse NMR: The epoxy resin cured material was cut into 2 cm lengths and placed in a 10 mm diameter glass sample can (Bruker). The sample can was placed in a pulse NMR spectrometer (Bruker Minispec mq20), and the temperature was gradually increased from room temperature to 120°C (held for 10 minutes) and 160°C (held for 10 minutes). Measurements were then performed at 120°C and 160°C using the Solid Echo method. １The free-induced damping curve for spin-spin relaxation of H was obtained. The measurement conditions using the Solid Echo method were: Scans: 8–16 times, Recycle Delay: 4 seconds, Acquisition scale: 2 ms.

[0102] obtained １ The free induction decay curve of spin-spin relaxation of H was waveform-separated into three curves derived from three components—hard, middle, and soft—based on the slope of the magnetization intensity. Waveform separation was performed by fitting using both Gaussian and exponential methods. The ratio of each component was determined from the three component-derived curves obtained from each measurement.

[0103] Furthermore, using BRUKER's analysis software "TD-NMRA (Version 4.3 Rev 0.8)," fitting was performed according to the product manual, with the hard component fitted using a Gaussian type and the middle and soft components fitted using an exponential type. In addition, the analysis was performed using points up to 0.6 msec of the relaxation curve to determine the component amount and relaxation time for each component.

[0104] The fitting was performed using the following equation (X): Y = A1 * exp(-1 / w1 * (t / T2A)^w1) + B1 * exp(-1 / w2 * (t / T2B)^w2) + C1 * exp(-1 / w3 * (t / T2C)^w3) ... equation (X)

[0105] In the above equation (X), w1, w2, and w3 are Weibull coefficients, where w1 is 2 and w2 and w3 are 1. In the above equation (X), A1 is the hard component content, B1 is the middle component content, C1 is the soft component content, T2A is the relaxation time of the hard component, T2B is the relaxation time of the middle component, and T2C is the relaxation time of the soft component. In the above equation (X), t is time.

[0106] By performing the pulsed NMR measurement and analysis described above using the obtained epoxy resin cured product, the following was determined.

[0107] Content of hard components at 120°C (%) out of 100% of the total content of hard components, medium components, and soft components at 120°C. Content of hard components at 160°C (%) out of 100% of the total content of hard components, medium components, and soft components at 160°C. Spin-spin relaxation time of hard components at 120°C (μs). Spin-spin relaxation time of hard components at 160°C (μs). Ratio (Spin-spin relaxation time of hard components at 160°C / Spin-spin relaxation time of hard components at 120°C).

[0108] The abbreviations used in the examples and comparative examples are as follows:

[0109] [Epoxy Resins] E1: Epoxy resin obtained in Example 1 E2: Epoxy resin obtained in Example 2 E3: Epoxy resin obtained in Example 3 E4: Epoxy resin obtained in Example 4 E5: Epoxy resin obtained in Example 5 E6: Epoxy resin obtained in Example 6 E7: Epoxy resin obtained in Example 7 E8: Epoxy resin obtained in Example 8 E9: Epoxy resin obtained in Example 9 E10: Epoxy resin obtained in Example 10 E11: Epoxy resin obtained in Example 11 E12: Epoxy resin obtained in Example 12 EH1: Epoxy resin obtained in Comparative Example 1 EH2: Epoxy resin obtained in Comparative Example 2 EH3: Epoxy resin obtained in Comparative Example 3 EH4: Epoxy resin obtained in Comparative Example 4

[0110] [Epoxy resin raw materials] P1: Phenolic resin obtained in Synthesis Example 1 P2: Bisphenol F (hydroxyl group equivalent 100 g / eq.) P3: Bisphenol A (hydroxyl group equivalent 114 g / eq.) P4: Bisphenol C (hydroxyl group equivalent 128 g / eq.) P5: Bisphenol M (hydroxyl group equivalent 173 g / eq.) P6: Bisphenol P (hydroxyl group equivalent 173 g / eq.) P7: Tetramethylbisphenol F (hydroxyl group equivalent 128 g / eq.) P8: Tetramethylbisphenol A (hydroxyl group equivalent 142 g / eq.) P9: 3,3',5,5'-Tetramethylbiphenyl-4,4'-diol (hydroxyl group equivalent 121 g / eq.) P10: t-Butylcatechol (hydroxyl group equivalent 83 g / eq.)

[0111] [Curing agent] A1: Active ester resin obtained in Synthesis Example 2

[0112] [Curing accelerator] C1: 4-dimethylaminopyridine

[0113] Synthesis Example 1 A reaction apparatus consisting of a glass separable flask equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser was used to add 140 parts of 2,6-xylenol (structural formula below). 47% BF ３ 9.3 parts of the ether complex were charged and heated to 100°C while stirring. While maintaining the same temperature, 154.6 parts of dicyclopentadiene (see structural formula below) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 115-125°C for 4 hours, and 11 parts of calcium hydroxide were added. Then, 19 parts of a 10% oxalic acid aqueous solution were added. After that, the mixture was heated to 160°C to dehydrate it, and then heated to 200°C under a reduced pressure of 5 mmHg to evaporate and remove any unreacted raw materials. 1320 parts of MIBK were added to dissolve the product, and 400 parts of 80°C warm water were added for washing, and the lower layer of water was separated and removed. Then, the mixture was heated to 160°C under a reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding a reddish-brown phenolic resin (P1, structural formula below). The hydroxyl group equivalent was 288 g / eq., Mw was 287, and Mn was 243.

[0114] Here, R ２２ Each independently represents a hydrogen atom or a dicyclopentadiene group. m3 is preferably 0.01 to 3.0, more preferably 0.01 to 2.5, and even more preferably 0.01 to 2.0.

[0115] Synthesis Example 2 A reaction apparatus consisting of a glass separable flask equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser was charged with 100 parts of dicyclopetanediene type phenol (J-DPP-95, manufactured by JFE Chemical Co., Ltd.), 138 parts of isophthalic acid chloride, 880 parts of toluene, 4 parts of tetrabutylammonium bromide, and 115 parts of 1-naphthol, and heated to 50°C while stirring. 274 parts of 20% sodium hydroxide aqueous solution were added dropwise over 3 hours and the reaction was allowed to proceed. After that, the temperature was raised to 80°C and the reaction was allowed to proceed for another 3 hours, then 310 parts of water were added, and the mixture was washed with water three times and the water was drained from the system. The temperature was then raised to 110°C to dehydrate the mixture, and the filtrate was obtained by filtration using filter paper. Then, under reduced pressure of 5 mmHg, the mixture was heated to 180°C to evaporate and remove toluene, obtaining a brown activated ester resin (A1). The ester equivalent was 220 g / eq., Mw was 1198, and Mn was 2076.

[0116] Example 1 A reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser was used to add 77 parts of the phenol resin (P1) obtained in Synthesis Example 1, 13 parts of bisphenol F, and 185 parts of epichlorohydrin (structural formula below). 55 parts of diethylene glycol dimethyl ether were added and the mixture was heated to 65°C. Under reduced pressure of 125 mmHg, 35.9 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63–67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and 290 parts of MIBK were added to dissolve the product. Then, 90 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the water wash was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove the MIBK by distillation, yielding a reddish-brown epoxy resin (E1). The epoxy equivalent was 254 g / eq. The melt viscosity was 0.005 Pa·s, Mw was 345, and Mn was 277. The GPC of the obtained epoxy resin (E1) is shown in Figure 3, and the IR is shown in Figure 4.

[0117] Example 2 The same procedure as in Example 1 was carried out except that phenolic resin (P1) was replaced with 58 parts and bisphenol F with 20 parts to obtain a reddish-brown epoxy resin (E2). The epoxy equivalent was 224 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 350, and Mn was 285.

[0118] Example 3 The same procedure as in Example 1 was carried out except that 38 parts of phenolic resin (P1) and 27 parts of bisphenol F were used to obtain a reddish-brown epoxy resin (E3). The epoxy equivalent was 199 g / eq., the melt viscosity was 0.003 Pa·s, Mw was 362, and Mn was 295.

[0119] Example 4 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 23 parts of bisphenol A were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E4). The epoxy equivalent was 228 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 349, and Mn was 286.

[0120] Example 5 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 26 parts of bisphenol C were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E5). The epoxy equivalent was 237 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 354, and Mn was 288.

[0121] Example 6 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 35 parts of bisphenol M were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E6). The epoxy equivalent was 267 g / eq., the melt viscosity was 0.008 Pa·s, Mw was 344, and Mn was 277.

[0122] Example 7 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 35 parts of bisphenol P were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E7). The epoxy equivalent was 267 g / eq., the melt viscosity was 0.008 Pa·s, Mw was 344, and Mn was 277.

[0123] Example 8 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 26 parts of tetramethylbisphenol F were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E8). The epoxy equivalent was 237 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 312, and Mn was 278.

[0124] Example 9 The same procedure as in Example 1 was carried out except that 38 parts of phenolic resin (P1) were used and 26 parts of tetramethylbisphenol F were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E9). The epoxy equivalent was 237 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 354, and Mn was 288.

[0125] Example 10 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 28 parts of tetramethylbisphenol A were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E10). The epoxy equivalent was 247, the melt viscosity was 0.005 Pa·s, Mw was 345, and Mn was 278 g / eq.

[0126] Example 11 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 24 parts of 3,3',5,5'-tetramethylbiphenyl-4,4'-diol were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E11). The epoxy equivalent was 233 g / eq., the melt viscosity was 0.005 Pa·s, Mw was 350, and Mn was 282.

[0127] Example 12 The same procedure as in Example 1 was carried out except that 58 parts of phenolic resin (P1) were used and 17 parts of t-butylcatechol were used instead of bisphenol F to obtain a reddish-brown epoxy resin (E12). The epoxy equivalent was 207 g / eq., the melt viscosity was 0.003 Pa·s, Mw was 348, and Mn was 280.

[0128] Comparative Example 1 The same procedure as in Example 1 was carried out except that 115 parts of phenolic resin (P1) were added and no bisphenols were added (0 parts) to obtain a reddish-brown epoxy resin (EH1). The epoxy equivalent was 344 g / eq., the melt viscosity was 0.6 Pa·s, Mw was 470, and Mn was 440.

[0129] Comparative Example 2 The same procedure as in Example 1 was carried out except that the phenolic resin (P1) was omitted (0 parts) and bisphenol F was added to 40 parts to obtain a colorless, transparent epoxy resin (EH2). The epoxy equivalent was 160 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 283, and Mn was 279.

[0130] Comparative Example 3: The same procedure as in Example 1 was followed, except that phenolic resin (P1) was omitted (0 parts) and bisphenol A was added (46 parts), to obtain a colorless, transparent epoxy resin (EH3). The epoxy equivalent was 170 g / eq., the melt viscosity was 0.004 Pa·s, Mw was 357, and Mn was 353.

[0131] Comparative Example 4: The same procedure as in Example 1 was followed, except that phenolic resin (P1) was omitted (0 parts) and bisphenol C was added (51 parts), to obtain a colorless, transparent epoxy resin (EH4). The epoxy equivalent was 192 g / eq., the melt viscosity was 0.008 Pa·s, Mw was 437, and Mn was 410.

[0132]

[0133]

[0134] Example 13 As shown in Table 3, 100 parts of epoxy resin E1 as the epoxy resin, 87 parts of active ester resin A1 as the curing agent, and 1 part of C1 as the curing accelerator were mixed and dissolved in toluene to obtain an epoxy resin composition varnish. The obtained epoxy resin composition varnish was impregnated into glass cloth (manufactured by Nitto Boseki Co., Ltd., WEA 7628 XS13, 0.18 mm thick). The impregnated glass cloth was dried in a hot air circulating oven at 150°C for 9 minutes to obtain a prepreg. The obtained prepreg was loosened and sieved to obtain a 100-mesh pass powdered prepreg powder. The obtained prepreg powder was placed in a fluororesin mold and vacuum pressed at 2 MPa under the temperature conditions of 130°C for 15 minutes + 210°C for 80 minutes to obtain a 50 mm square x 2 mm thick test specimen. The relative permittivity and dielectric loss tangent results of the test specimen are shown in Table 4. The pulse NMR measurement results using the same test specimen are shown in Table 4. Furthermore, Figure 5 shows a graph comparing the hard component ratios of Example 13 and Comparative Example 5.

[0135] Examples 14-24 and Comparative Examples 5-8: The mixtures were prepared using the amounts (parts) shown in Tables 3 and 5, and the same procedure as in Example 13 was followed to obtain test specimens. The amount of curing accelerator used was adjusted to the extent that the varnish gel time was approximately 300 seconds. The same test as in Example 13 was performed, and the results are shown in Tables 4 and 6.

[0136]

[0137]

[0138]

[0139]

Claims

1. An epoxy resin cured product used as an insulating material, wherein, based on a free induction decay curve at 120°C obtained using pulsed NMR measured by the Solid echo method, the components contained in the cured product are separated into three components in order of increasing spin-spin relaxation time: a hard component at 120°C, a middle component at 120°C, and a soft component at 120°C, and, based on a free induction decay curve at 160°C obtained using pulsed NMR measured by the Solid echo method, the components contained in the cured product are separated into three components in order of increasing spin-spin relaxation time: a hard component at 160°C, a middle component at 160°C, and a soft component at 160°C, wherein the content of the hard component at 160°C is 10% or more and less than 60% of the total 100% of the content of the hard component at 160°C, the content of the middle component at 160°C, and the content of the soft component at 160°C. An epoxy resin cured product characterized in that the ratio of the spin-spin relaxation time of the hard component at 160°C to the spin-spin relaxation time of the hard component at 120°C is 1.30 or more, the spin-spin relaxation time of the hard component at 120°C is 10.0 microseconds or more and 22.0 microseconds or less, and the spin-spin relaxation time of the hard component at 160°C is 18.0 microseconds or more and 30.0 microseconds or less.

2. An epoxy resin composition for obtaining the epoxy resin cured product described in claim 1, characterized in that it contains an epoxy resin having a melt viscosity of 0.001 to 0.10 Pa·s at 150°C, and also contains a curing agent.

3. The epoxy resin composition according to claim 2, characterized in that the epoxy resin comprises an epoxy resin component (A) represented by general formula (1) and an epoxy resin component (B) represented by the following general formula (5a) or (5b). (Here, X is independently a divalent group containing a group represented by formula (2), (3a), or (3b) below. Z independently represents a glycidyl group or a group represented by formula (4a) or (4b) below. However, of the Z in formulas (1) and (2), at least one is a glycidyl group. n indicates the number of repetitions, and its average value is between 0 and 10.) (Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, where i is an integer from 1 to 4, but both 4-i and 3-i are greater than or equal to 0. ２ represents either a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. m1 indicates the number of repetitions, the average value of which is between 0.01 and 5. (Here, R ３ (where 'a' independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and 'j' is 1 to 4, and each may be the same group or different groups. 'Y' represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms, which may contain heteroatoms.) (Here, R ３ (Each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and q is 1 to 4, which may be the same group or different groups.) G represents a glycidyl group, and s1 is 0 or 1. Y represents a directly bonded alkylene group, an alkylene group which may have substituents, or an alkylene group which may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms which may contain heteroatoms. (Here, R ３ The atoms independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and these may be the same group or different groups. G represents a glycidyl group, where s2 is 1 or 2, s3 is an integer from 1 to 5, and s2 + s3 is an integer from 2 to 6. Y represents an alkylene group that is directly bonded, may have substituents, or may have aromatic groups. The substituents are hydrocarbon groups having 1 to 10 carbon atoms, which may contain heteroatoms.

4. The epoxy resin composition according to claim 2 or 3, characterized in that the curing agent is a polyvalent hydroxy resin represented by the following general formula (6) or an activated ester resin. (Here, R １ R independently represents a hydrocarbon group having 1 to 10 carbon atoms, where i is an integer from 1 to 4, but both 4-i and 3-i are greater than or equal to 0. ２１ (Each represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. m3 indicates the number of repeats, with an average value of 0 to 5.) 5. A prepreg characterized by using the epoxy resin composition described in claim 2 or 3.

6. A laminate characterized by using the epoxy resin composition described in claim 2 or 3.

7. A printed circuit board characterized by using the epoxy resin composition described in claim 2 or 3.

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