JP2013194137A - Prepreg including polyphenylene ether particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a dispersion liquid containing a resin composition including PPE particles, which gives low dielectric constant and dielectric loss tangent which polyphenylene ether (PPE) originally has, and excellent heat resistance and adhesiveness; a prepreg manufactured by using the dispersion liquid; and a printed wiring board manufactured from the prepreg.SOLUTION: In a dispersion liquid containing a resin composition including PPE particles and a solvent, (1) PPE particles have such a size that the major axis is ≤30 μm, (2) ≥60% of the total particle number of the PPE particles has such a size that the major axis is ≥3 μm and ≤20 μm, (3) the PPE particles include ≥70 mass% PPE, and (4) the number average molecular weight of PPE included in the PPE particles is 8,000-40,000.

Description

  The present invention is a prepreg composed of a curable resin composition containing polyphenylene ether (hereinafter also referred to as PPE) particles and a base material, which is suitable as an electronic substrate material, and electricity and electrons formed using the prepreg. The present invention relates to a laminated board for components and a printed wiring board.

In recent years, due to remarkable progress in information network technology and expansion of services utilizing information networks, electronic devices are required to have a large amount of information and a high processing speed. In order to transmit a digital signal with a large capacity and high speed, it is effective to shorten the wavelength of the signal, and the frequency of the signal is increasing. However, since an electric signal in a high frequency region is easily attenuated by a wiring circuit, a printed wiring board having good transmission characteristics is required.
PPE has a low dielectric constant and dielectric loss tangent and is excellent in high-frequency characteristics (that is, dielectric characteristics), and therefore is suitable as a material for printed wiring boards of electronic devices that use a high frequency band.
On the other hand, since PPE lacks solubility in organic solvents, when producing prepregs necessary for printed wiring board production, varnish is produced by dissolving in a halogen-based solvent such as chloroform, or heated to 50 ° C or higher. It was necessary to produce the varnish by dissolving it in an aromatic organic solvent such as toluene or xylene.

In order to solve this problem, Patent Document 1 describes a method of reducing the molecular weight of PPE to about 3,000 and increasing the solubility in a solvent. Patent Document 2 reports a technique for converting a terminal hydroxyl group of a low molecular weight PPE into a reactive functional group to improve solubility in a solvent and improve heat resistance.
In Patent Documents 3 and 4, a toluene resin solution of a resin composition containing a crosslinkable resin such as PPE and a styrene butadiene copolymer and a crosslinking aid such as triacyl isocyanurate is once heated to 35 ° C. or higher and then cooled. In addition, there is described a method of preparing an opaque dispersion in which particles of a resin composition containing PPE, a crosslinkable resin, and a crosslinking aid are dispersed.
Further, Patent Document 5 describes a method of dispersing PPE resin powder having an average particle size of 10 to 50 μm in a solvent such as methyl ethyl ketone, and Patent Document 6 describes a method of dispersing PPE particles of 106 μm or less in an aqueous system. .

JP 2003-265777 A Special table 2009-509912 JP 7-292126 A JP-A-9-290481 JP 2008-50526 A JP 2003-34731 A

However, the method of increasing the solubility in a solvent using the low molecular weight PPE described in Patent Document 1 has a problem that the heat resistance of the resulting laminate is lowered, and the number of terminal hydroxyl groups of the PPE increases so that the dielectric constant. In addition, since the dielectric loss tangent is increased, it is not sufficient for use in a printed wiring board.
In addition, the method of increasing the solubility in a solvent using the low molecular weight / reactive functionalized PPE described in Patent Document 2 improves the problem of heat resistance reduction due to the low molecular weight, but seals the terminal hydroxyl group. It has a problem that is presumed to be caused by this. That is, such PPE does not have sufficient adhesion to a substrate such as glass cloth or copper foil, and has low peel strength between layers in the case of a laminated plate or peel strength between the PPE and copper foil. Alternatively, there is a problem that water absorption resistance and solder heat resistance are not sufficient.

  In the methods described in Patent Documents 3 and 4, the dispersion of particles of a resin composition containing PPE, a crosslinkable resin, and a crosslinking aid has a very high viscosity. Is not sufficient in that it is difficult to obtain and inferior in impregnation into the substrate. Actually, when the methods disclosed in Example 1 and Example 2 of Patent Document 3 are traced faithfully, the dispersion becomes grease-like and cannot be used for coating, or even if it can be applied. The impregnation to a base material was bad and only what was inferior to the adhesiveness of a base material and a resin composition was obtained. When this dispersion was diluted and observed with an optical microscope, very small particles of 3 μm or less were dense. As described above, when the temperature is lowered under conditions of high concentration and high viscosity in which PPE, processable resin and crosslinkable resin are mixed, crystals such as PPE do not grow, and many very small crystals are generated, resulting in a grease-like state. It is thought that it became.

  The method described in Patent Document 5 is not sufficient in that PPE is dispersed in a poor solvent, so that the dispersion stability of the dispersion lacks, PPE tends to settle, and uniform coatability and continuous coatability are lacking. . In addition, when impregnating a base material such as glass cloth, the moving speed of the dispersion solvent and PPE to the base material is increased, so that only PPE is deposited on the impregnation roll.

  The method described in Patent Document 6 is stably dispersed in an aqueous solvent using a surfactant. However, since the PPE particles are as large as 106 μm or less, for example, the TAIC described in Patent Document 6 is used. When a curable resin composition is used as a curable monomer, a PPE and TAIC cannot be completely mixed in the process of normal heat and pressure molding conditions when preparing a cured product composite from a prepreg. Since the obtained substrate lacks uniformity, it has disadvantages inferior to solder heat resistance and drilling workability.

  As described above, a resin dispersion having a low dielectric constant and a dielectric loss tangent inherent to PPE, and excellent in heat resistance and adhesiveness, which can be applied at room temperature, has not been found in the prior art. It is. Accordingly, there has been a strong demand for a resin dispersion that can be applied at room temperature and that has the above-described characteristics while using PPE as a constituent component.

  Under the circumstances described above, the problem to be solved by the present invention is that the low dielectric constant and dielectric loss tangent inherent in PPE, and excellent heat resistance and adhesion (for example, peel strength between layers in a multilayer board, or curable resin composition) A dispersion containing a resin composition containing PPE particles, a prepreg produced using the dispersion, and a prepreg produced from the prepreg. Printed wiring board.

As a result of intensive studies and repeated experiments to solve the above-mentioned problems, the present inventors crystallized PPE in a solvent to form PPE particles, and set the particle size of the PPE particles and the PPE content ratio within a specific range. Can improve the swellability, fluidity, and dispersion stability of PPE, so that coating of the varnish containing the dispersion can be performed at room temperature, and the prepreg and the prepreg obtained can be manufactured by heat and pressure molding. It has been found that the adhesiveness between the curable resin containing PPE and the base material of the substrate to be improved is improved, and the present invention has been completed based on such knowledge.
That is, the present invention is as follows.

[1] A dispersion containing a resin composition containing polyphenylene ether (PPE) particles and a solvent,
(1) The PPE particles have a major axis size of 30 μm or less,
(2) 60% or more of the total number of PPE particles is a size of 3 μm to 20 μm in major axis,
(3) The PPE particles contain 70% by mass or more of PPE, and (4) the number average molecular weight of the PPE contained in the PPE particles is 8,000 to 40,000.
Said dispersion.

  [2] A dispersion containing PPE particles according to [1], wherein the solubility of PPE in the solvent at 25 ° C. is 3% by mass or more and 20% by mass or less.

  [3] The dispersion liquid contains dissolved PPE in addition to the PPE particles, and the mass ratio (A) :( B) of the PPE particles (A) to the dissolved PPE (B) is 85:15 to 15:15. The dispersion according to [1] or [2], wherein the dispersion is 30:70.

  [4] The dispersion according to [3], wherein the mass ratio (A) :( B) of the PPE particles (A) to the dissolved PPE (B) is 80:20 to 45:55.

  [5] The dispersion according to [3] or [4], wherein the dissolved PPE (B) has a number average molecular weight of 5,000 to 40,000.

  [6] The dispersion according to any one of [1] to [5], wherein the PPE component contained in the resin composition is in an amount of 10% by mass to 70% by mass based on the resin composition. .

  [7] The dispersion according to any one of [1] to [6], further including a crosslinkable curable resin (C) and an initiator (D).

  [8] The dispersion according to [7], wherein the crosslinkable curable resin (C) is a monomer having two or more vinyl groups in the molecule.

  [9] The dispersion according to [7], wherein the crosslinkable curable resin (C) is triallyl isocyanurate (TAIC).

  [10] A resin varnish containing the dispersion according to any one of [1] to [9].

  [11] A prepreg obtained by applying a varnish containing the dispersion according to any one of [1] to [9] to a substrate, and then removing the solvent from the substrate to which the dispersion is applied.

  [12] A printed wiring board produced using the prepreg obtained in [10] as a constituent component.

  According to the present invention, since a PPE can be crystallized and the swelling property and particle size of the PPE can be controlled within an appropriate range, a dispersion of a resin composition containing PPE particles having good varnish stability and coating uniformity is provided. Can do. Furthermore, by crystallization of PPE under conditions with a high PPE content and forming crystal particles mainly composed of PPE, the adhesion between the resin component of the prepreg produced using the dispersion and the substrate can be improved. Good and excellent heat resistance and adhesion (for example, peel strength between layers in a multilayer board, or peel strength between a cured product of a curable resin composition and a metal foil such as copper foil) Dispersions from which materials can be obtained, printed wiring prepregs manufactured using the dispersions, and printed wiring boards including cured products of the prepregs can be provided.

The carbon nuclear magnetic resonance spectroscopy spectrum of the extract (A) obtained by the method of Example 1 and the carbon magnetic resonance spectroscopy spectrum of the standard substance.

｛式中、Ｒ１、Ｒ２、Ｒ３及びＲ４は、各々独立して、水素原子、ハロゲン原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいアリール基、置換基を有してもよいアミノ基、ニトロ基又はカルボキシル基を表す。｝で表される繰返し構造単位を含む。 Hereinafter, although the embodiment of the present invention is described in detail, it is not intended that the present invention be limited to these embodiments.
One embodiment of the present invention is a prepreg composed of a curable resin composition containing PPE particles and a substrate.
The PPE contained in the curable resin composition of this embodiment is preferably the following general formula (1):

{Wherein R1, R2, R3 and R4 each independently have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or a substituent. An aryl group that may be substituted, an amino group that may have a substituent, a nitro group, or a carboxyl group. } Is included.

Specific examples of PPE include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2-methyl-6). -Phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether) and the like, and 2,6-dimethylphenol and other phenols (for example, 2,3,6-phenylene ether) And a polyphenylene ether copolymer obtained by coupling 2,6-dimethylphenol and biphenols or bisphenols, and the like. A preferred example is poly (2,6-dimethyl-1,4-phenylene ether).
In the present specification, PPE means a polymer composed of a substituted or unsubstituted phenylene ether unit structure, but may contain other copolymerization components as long as the effects of the present invention are not impaired.

In the first embodiment of the present invention, the maximum major axis of the PPE particles (A) contained in the dispersion is 30 μm or less. A preferable range of the maximum major axis of the PPE particles (A) is 25 μm or less, a more preferable range is 20 μm or less, and a further preferable range is 17 μm or less.
Here, the maximum major axis of the PPE particles (A) is a value determined by the following measurement. That is, the solvent is dried and removed at a temperature not higher than the boiling point of the solvent so that the solvent content is 1% by mass or less from the dispersion. Next, 20 g of a mixed solvent of toluene and methanol having a mass ratio of 95: 5 at 23 ° C. ± 2 ° C. is added to 1.5 g of the dispersion from which the solvent has been removed by drying. Allow 1 hour to elapse while shaking vigorously every 5 minutes in a constant temperature room at 23 ° C. ± 2 ° C. Next, it is allowed to stand for 24 hours in the same constant temperature room. Next, the supernatant is removed, 5 g of a mixed solvent of toluene and methanol having a mass ratio of 95: 5 is added, and the mixture is shaken vigorously again, and then allowed to stand in the same thermostatic chamber for 24 hours. Next, the supernatant is removed, and 5 g of a mixed solvent of toluene and methanol having a mass ratio of 95: 5 is added. After shaking so as to be uniformly dispersed, the dispersion is taken out and dropped onto a sample stage for SEM-EDX measurement. After the solvent is volatilized, SEM-EDX observation is performed, and the major axis of the primary particles is measured with PPE particles (A) having particles with a total of 95% or more of carbon, oxygen, and hydrogen. A straight line is drawn so as to pass through the inside of the primary particle, and the length when the straight line becomes the longest is defined as the major axis of the primary particle. The major axis of 400 or more primary particles is randomly measured, and the maximum value is taken as the maximum major axis.

  When the maximum major axis of the PPE particles (A) is in the above-mentioned range, the dispersion stability of the dispersion liquid is good, so that a prepreg having a uniform distribution of PPE particles can be obtained by applying the varnish containing the dispersion liquid to the base material. Since it is obtained, it is preferable. Furthermore, since the thing which has sufficient heat resistance as a hardened | cured material composite body mentioned later is obtained, it is preferable. This is because the PPE particles (A) and the PPE particles (A) can be melted at an early stage under normal heat and pressure molding conditions when preparing a cured product composite from the prepreg. This is considered to be because the distribution of the PPE component in the resulting cured product can be made uniform by uniformly mixing with other curable resin components.

  In the first embodiment of the present invention, 60% or more of the total number of PPE particles (A) contained in the dispersion liquid has a major axis of 3 μm or more and 20 μm or less. A preferable range of the ratio of the number of particles having a major axis of 3 μm or more and 20 μm or less is 70% or more and 100% or less, and a more preferable range is 80% or more and 100% or less. Here, the ratio of the number of PPE particles (A) having a major axis of 3 μm or more and 20 μm or less to the number of all PPE particles (A) is a value determined by the following measurement. First, the major axis of 400 or more PPE particles (A) is randomly measured on the SEM-DEX image by the same method as the method for obtaining the maximum major axis of the PPE particles (A). Next, the number of PPE particles (A) having a particle diameter of 3 μm or more and 20 μm or less is obtained, the ratio to the total number of particles measured is calculated, and the PPE particles (A) having a major axis of 3 μm or more and 20 μm or less with respect to the number of all PPE particles (A). A percentage of numbers.

When 60% or more of the PPE particles (A) are in the range of 3 μm or more and 20 μm or less in the major axis, good fluidity is obtained as long as the dispersion stability of the dispersion and the varnish containing the dispersion and the crosslinkable curable resin is maintained. It is preferable because it is secured. Furthermore, since the thing which has sufficient heat resistance as a hardened | cured material composite body mentioned later is obtained, it is preferable. This is because the PPE particles (A) and the PPE particles (A) can be melted at an early stage under normal heat and pressure molding conditions when preparing a cured product composite from the prepreg. This is considered to be because the distribution of the PPE component in the resulting cured product can be made uniform by uniformly mixing with other curable resin components.
The ratio of particles having a major axis of 3 μm or more and 20 μm or less is preferably higher, and most preferably all particles fall within the above particle size range.

In the first embodiment of the present invention, the PPE particles (A) contained in the dispersion contain 70% by mass or more of PPE. A preferable range of the PPE content ratio in the PPE particles (A) is 75% by mass or more, and a more preferable range is 80% by mass or more. Here, the PPE content ratio in the PPE particles (A) is a value determined by the following measurement.
The solvent is dried and removed from the dispersion at a temperature not higher than the boiling point of the solvent so that the solvent content is 1% by mass or less. Then, 20 g of a mixed solvent of toluene and methanol having a mass ratio of 95: 5 at 23 ° C. ± 3 ° C. is added to 1.5 g of the dispersion from which the solvent has been removed by drying. Allow 1 hour to elapse while shaking vigorously every 5 minutes in a constant temperature room at 23 ° C. ± 2 ° C. Next, it is allowed to stand for 24 hours in the same constant temperature room. Next, the supernatant is removed, 5 g of a mixed solvent of toluene and methanol with a mass ratio of 95: 5 is added, shaken vigorously, and then allowed to stand in the same constant temperature room for 24 hours. Next, the supernatant is removed, and 5 g of a mixed solvent of toluene and methanol having a mass ratio of 95: 5 is added (the same procedure as that for obtaining the maximum major axis of the PPE particles (A) described above). Next, after removing the solvent by drying, it is developed in chloroform, and insolubles are removed by filtration to obtain an extract (hereinafter, this extract is also referred to as “extract (A)”). The amount of PPE in the extract (A) is quantified by carbon nuclear magnetic resonance spectroscopy to obtain the PPE content ratio in the PPE particles (A).

Quantification of PPE using carbon nuclear magnetic resonance spectroscopy can be performed by the following method. Tetramethylsilane is used as a standard for chemical shift, and its peak is 0 ppm. As the peak of PPE, the intensities of peaks near 16.8, 114.4, 132.5, 145.4, and 154.7 ppm are totaled, and the ratio to the peak intensity of tetramethylsilane is X. If this value for the standard substance is X1, and the value for the extract (A) is X2, the PPE content in the extract can be measured by calculating the value of (X2 / X1) × 100. . Here, the signal derived from the PPE may be used at the same position as the standard material, and is not limited to the above. For quantitative determination, the ratio of peak intensities obtained from the same measurement sample amount using poly (2,6-dimethyl-1,4-phenylene ether) having a number average molecular weight of 15,000 to 25,000 as a standard substance. Find using. As poly (2,6-dimethyl-1,4-phenylene ether) having a number average molecular weight of 15,000 to 25,000, for example, S202A grade manufactured by Asahi Kasei Chemicals Corporation can be used.
FIG. 1 shows the carbon nuclear magnetic resonance spectroscopy spectrum of the extract (A) obtained by the method of Example 1 and the carbon magnetic resonance spectroscopy spectrum of the standard substance for reference. First, from the NMR spectrum of the standard substance, the sum of the ratios of the signal strengths of 16.8, 114.4, 132.5, 145.4, 154.7 ppm derived from PPE and the signal strength of tetramethylsilane, The signal intensity value (1) of the standard substance is used. Next, in the NMR spectrum of Example 1, the ratio of the signal intensity of 16.8, 114.4, 132.5, 145.4, and 154.7 ppm at the same signal position as that of the standard material to the signal intensity of tetramethylsilane. Is the signal intensity value (X2) of the first embodiment. Using the values of X1 and X2, the following formula:
PPE content ratio in PPE particles = (X2 / X1) × 100 = 83%
Was used to determine the PPE content in the PPE particles (A).

If the PPE component contained in the PPE particles (A) is in the above-mentioned range, it is preferable because the PPE particles having the above-mentioned particle size are easily obtained by PPE crystallization. Furthermore, since the thing which has sufficient heat resistance as a hardened | cured material composite body mentioned later is obtained, it is preferable. This is because the PPE particles (A) and the PPE particles (A) can be melted at an early stage under normal heat and pressure molding conditions when preparing a cured product composite from the prepreg. This is considered to be because the distribution of the PPE component in the resulting cured product can be made uniform by uniformly mixing with other curable resin components.
The PPE content ratio in the PPE particles (A) is preferably high, and most preferably composed of all PPE components.

In the first embodiment of the present invention, the number average molecular weight of PPE contained in the PPE particles (A) contained in the dispersion is 8,000 or more and 40,000 or less. A preferred range of the number average molecular weight of PPE contained in the PPE particles (A) is from 8,500 to 30,000, and a more preferred range is from 9,000 to 25,000.
Here, the number average molecular weight of PPE in the PPE particles (A) is a value obtained by the following measurement. The extract (A) obtained by measuring the PPE content in the PPE particles (A) described above was used as a measurement sample, Shodex LF-804 × 2 (manufactured by Showa Denko KK) as the column, and chloroform at 50 ° C. as the eluent. The gel permeation chromatography (GPC) is measured using RI (refractometer) as a detector, and is measured in terms of standard polystyrene from the relational expression between the molecular weight and elution time of the standard polystyrene sample measured under the same conditions. The value is the number average molecular weight of the PPE particles (A).
The number average molecular weight of the PPE particles (A) is 8,000 or more, which is desired in a printed wiring board or the like, the water absorption resistance of the cured product, solder heat resistance, and adhesiveness (for example, the peel strength between layers in a multilayer board, Or it is preferable at the point which gives favorable the peeling strength of the hardened | cured material of a curable resin composition, and copper foil etc. Moreover, the number average molecular weight of PPE particle (A) is 40,000 or less, and the melt viscosity of the curable resin composition at the time of shaping | molding is small, and it is preferable at the point from which favorable moldability is obtained.

  For the dispersion containing the resin composition containing the PPE particles of the present invention and the solvent, it is preferable to use a solvent having a solubility of PPE at 25 ° C. of 3% by mass or more and 20% by mass or less. More preferably, the solubility of PPE at a temperature of 80 ° C. is 20% by mass or more. Although there is no particular limitation as long as the solubility of PPE is in the above range, preferred solvents include aromatic organic solvents such as benzene, toluene, xylene, ketones such as cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, butanol, etc. These alcohols may be one kind of these solvents, or two or more kinds of mixed solvents. By making the solubility of PPE a solvent in the above-mentioned range, the swelling property, fluidity, and dispersion stability of the PPE particles are improved, and the adhesiveness of the prepreg obtained by coating at normal temperature is improved. It is preferable because it can be made appropriate.

In the first embodiment of the present invention, the dispersion contains dissolved PPE in addition to the PPE particles, and the mass ratio (A) :( B) between the PPE particles (A) and the dissolved PPE (B) is 85: 15-30: 70. A more preferable range of the weight ratio (A) :( B) between the PPE particles (A) and the PPE (B) is 80:20 to 45:55, and a more preferable range is 75:25 to 50:50.
Here, let mass ratio of (A) and (B) be a value calculated | required by the following measurements.
First, the mass of the PPE particles (A) contained in 1.5 g of the dispersion liquid from which the solvent has been removed by drying is determined as follows. Extract A is obtained by the same procedure as when the PPE content of the above-mentioned PPE particles (A) was obtained, the solvent used for extraction was removed by drying, and the solvent removed the mass of the resulting extract A by drying. The mass of the PPE particles (A) contained in 1.5 g of the resulting dispersion.
Next, the mass of PPE (B) contained in 1.5 g of the dispersion liquid from which the solvent has been removed by drying is determined as follows. All the supernatant liquid when the PPE content ratio in the PPE particles (A) is measured according to the above-described procedure is recovered. The solvent of the supernatant is removed by drying, and the mass of the curable resin composition soluble in the solvent is measured.
Subsequently, the PPE content ratio in the curable resin composition soluble in the solvent is quantitatively determined by nuclear magnetic resonance spectroscopy as in the measurement of the PPE content ratio in the PPE particles (A). From the mass of the curable resin composition soluble in the solvent and the content of PPE in the soluble solidifiable resin composition obtained by the above-described method, a dispersion obtained by drying and removing the solvent 1. The mass of the PPE component (B) contained in 5 g is determined.
The mass of the PPE particles (A) insoluble in a mixed solvent of toluene and methanol having a mass ratio of 95: 5, contained in 1.5 g of the dispersion obtained by drying and removing the solvent, obtained by the method described above, and the solvent The mass ratio of (A) and (B) is determined from the mass of PPE (B) that is soluble in.

  It is preferable that the weight ratio of PPE particles (A) and PPE (B) in the dispersion is the same as 85:15 or a ratio of (A) is smaller than that because the heat resistance of the substrate becomes good. This is considered because PPE can be uniformly distributed in the cured product of the curable resin composition in the curable composite described later. Moreover, when the weight ratio of PPE particles (A) and PPE (B) is the same as 30:70 or the ratio of (A) is more than that, the base material and thermosetting resin composition in the cured product composite described later This is preferable because the adhesiveness to the cured body becomes good. Although it is not certain as to this cause, as described above, in the PPE particles (A) whose melting rate is slower than the thermosetting resin component other than the PPE particles (A) under the normal heating and pressure molding conditions of the prepreg. Due to the presence of a large amount of PPE, the thermosetting resin component other than the PPE particles (A) first melts to cover the surface of the substrate, and the PPE melted with a delay from the PPE particles (A) It is thought that this is because the thermosetting resin component is cured in the melted state.

The number average molecular weight of the PPE (B) dissolved in the dispersion is preferably 5,000 to 40,000. The more preferable range of the number average molecular weight of PPE (B) is 5,500 or more and 30,000 or less, and the more preferable range is 6,000 or more and 25,000 or less.
Here, the number average molecular weight of dissolved PPE (B) is a value determined by the following measurement. All the supernatant liquid when the PPE content ratio in the PPE particles (A) is measured according to the above-described procedure is recovered. A soluble component is separated from the supernatant by silica gel column chromatography to obtain a PPE separation liquid. Next, the molecular weight of PPE (B) contained in the PPE separation liquid is subjected to GPC measurement by the same method as the measurement of the number average molecular weight of PPE in the PPE particles (A), and the value measured in terms of standard polystyrene is dissolved PPE. The number average molecular weight of (B).
The number average molecular weight of the dissolved PPE (B) in the dispersion is preferably 5,000 or more, and the electric characteristics of the printed wiring board produced using the dispersion are improved. The number average molecular weight of dissolved PPE (B) is 40,000 or less, and the prepreg obtained by impregnating the base material with a varnish containing a PPE particle dispersion has a low melt viscosity of the curable resin composition at the time of molding. It is preferable in that a good moldability is obtained.

In the first embodiment of the present invention, the PPE component contained in the dispersion is preferably 10% by mass or more and 70% by mass or less based on the mass of the curable resin composition contained in the dispersion. . A more preferable range of the proportion of the PPE component in the resin composition is 13% by mass to 60% by mass, and a further preferable range is 15% by mass to 50% by mass.
Here, the ratio of the PPE component contained in the dispersion to the curable resin component is a value determined by the following method.

First, the amount of the curable resin composition in the dispersion is determined by the following method.
The solvent is dried and removed from the dispersion at a temperature not higher than the boiling point of the solvent so that the solvent content is 1% by mass or less. Next, 50 g of chloroform at 23 ° C. ± 2 ° C. is added to 1.5 g of the dispersion from which the solvent has been removed by drying. In a constant temperature room of 23 ° C. ± 2 ° C., after 1 hour while vigorously shaking every 5 minutes, the curable resin composition dissolved in chloroform is collected by filtration. Subsequently, 50 g of chloroform at 23 ° C. ± 2 ° C. was added to the extraction residue, and after vigorously shaking every 1 hour and 5 minutes in a constant temperature room at 23 ° C. ± 2 ° C., hardening dissolved in chloroform by filtration The resinous resin composition is recovered. The collected chloroform solution for two times was combined, the solvent was removed to obtain a curable resin composition, the weight thereof was measured, and the curable resin composition contained in 1.5 g of the dispersion liquid from which the solvent was removed by drying. Mass.
Further, the amount of the PPE component contained in the dispersion was determined by the method described above, and the mass of the PPE particles (A) contained in 1.5 g of the dispersion from which the solvent was removed by drying and the solvent was removed by drying. Obtained as the sum of the masses of PPE (B) contained in 1.5 g of the dispersion.
The mass ratio of the PPE component to the curable resin composition is determined from the mass of the curable resin composition and the mass of the PPE component contained in 1.5 g of the dispersion obtained by drying and removing the solvent. Ask.

  When the proportion of the PPE component in the resin composition is 10% by mass or more, the viscosity of the dispersion liquid is appropriately increased and the dispersion stability of the dispersion liquid is increased, which is preferable. Moreover, since the PPE content in the printed wiring board obtained by heat-press molding the prepreg obtained by applying the varnish containing the dispersion to a substrate is increased, the printed wiring board has excellent electrical characteristics. preferable. When the proportion of the PPE component in the resin composition is 70% or less, it is preferable because the melt viscosity of the prepreg containing PPE particles is prevented from becoming too high in the heat and pressure molding process, and a uniform and good molded product can be obtained. .

  The average number of phenolic hydroxyl groups per molecule of PPE contained in the curable resin composition of this embodiment can be 0.3 or more. The average number of phenolic hydroxyl groups per PPE molecule is preferably 0.7 or more, more preferably 0.9 or more, and still more preferably 1.05 or more. When PPE having an average number of phenolic hydroxyl groups per molecule of 0.3 or more is used in the curable resin composition, the adhesion between the cured product of the resin composition and a substrate (for example, glass cloth), or the Adhesion between the cured product of the resin composition and a metal foil such as a copper foil is improved, and the printed circuit board has water absorption resistance, solder heat resistance, and adhesiveness (for example, peeling strength between layers in a multilayer board, or cured product) Is preferable because it is excellent in peel strength between the copper foil and the copper foil. The average number of phenolic hydroxyl groups is a viewpoint that can suppress an increase in water absorption of a composite (for example, a laminate) containing a cured product of the curable resin composition and a substrate, or a dielectric constant of the composite From the viewpoint of suppressing an increase in dielectric loss tangent, it is preferably 2.0 or less, more preferably 1.85 or less, and still more preferably 1.6 or less.

The average number of phenolic hydroxyl groups per molecule of PPE is defined as a value determined by the following method. Polymer Papers, vol. 51, no. 7 (1994), in accordance with the method described on page 480, from a value obtained by measuring the change in absorbance at a wavelength of 318 nm of a sample obtained by adding a tetramethylammonium hydroxide solution to a methylene chloride solution of PPE using an ultraviolet-visible spectrophotometer. Obtain the number of hydroxyl groups. Separately, the number average molecular weight of PPE is determined by gel permeation chromatography (GPC), and the number of PPE molecules is determined using this value. From these values, the following formula:
According to the average number of phenolic hydroxyl groups per molecule = number of hydroxyl groups / number average number of molecules, the average number of hydroxyl groups per molecule of PPE is calculated.

  The average number of phenolic hydroxyl groups per molecule of PPE is, for example, by mixing PPE in which the phenolic hydroxyl group at the molecular end remains with PPE in which the phenolic hydroxyl group at the molecular end is modified with another functional group. It can be adjusted by changing the mixing ratio. Or it can adjust also by changing the substitution degree by the other functional group of the phenolic hydroxyl group of a molecule terminal. The mode of the functional group is not particularly limited, and may be a benzyl group, an allyl group, a propargyl group, a glycidyl group, a vinylbenzyl group, a methacryl group, or the like. Among them, from the viewpoints of being easy to obtain industrially due to good reaction efficiency, being excellent in stability without own reactivity, and having a remarkable effect of reducing the melt viscosity of the polyphenylene ether-containing composition during press molding, etc. The functional group is preferably a benzyl group.

  The polyphenylene ether used is (A-1) a PPE component having an average number of phenolic hydroxyl groups per molecule of less than 0.5 and a number average molecular weight of 1,000 to 8,000. (Hereinafter also referred to as low molecular weight / terminal functionalized PPE) is preferably contained in an amount of 1% by mass to 40% by mass with respect to the total amount of PPE. A more preferable range of the content of the low molecular weight / end-functionalized PPE is 1.2% by mass or more and 30% by mass or less, and a further preferable range is 1.5% by mass or more and 25% by mass or less.

  The number average molecular weight of PPE is a value measured in terms of standard polystyrene using gel permeation chromatography (GPC). Typically, GPC measurement was performed under the same conditions using Shodex LF-804 × 2 (manufactured by Showa Denko KK) for the column, RI (refractometer) for the chloroform detector at 50 ° C. for the eluent. The number average molecular weight is calculated from the relational expression between the molecular weight of the standard polystyrene sample and the elution time.

  (A-1) A curable resin composition containing PPE containing 1% by mass or more of low molecular weight / end-functionalized PPE has a low melt viscosity of the curable resin composition at the time of molding, and good moldability is obtained. This is preferable. On the other hand, the curable resin composition containing PPE containing 40% by mass or less of the low molecular weight / end-functionalized PPE suppresses the remarkable expression of the characteristics of the low molecular weight / end-functionalized PPE, which is inferior in adhesiveness. Desired for printed wiring boards, etc., water absorption resistance, solder heat resistance, and adhesiveness of cured products (for example, peel strength between layers in a multilayer board, or cured product of a curable resin composition and copper foil, etc. In terms of giving good peel strength).

  The average number of phenolic hydroxyl groups per molecule of (A-1) low molecular weight / end-functionalized PPE is preferably less than 0.5, more preferably 0.2 or less, and still more preferably. 0.1 or less. If the average number of phenolic hydroxyl groups is less than 0.5, the curable resin composition containing the low molecular weight and end-functionalized PPE can form a cured product having a low dielectric constant and dielectric loss tangent, as well as good curing. Since it has reactivity, it is preferable at the point from which the hardened | cured material excellent in the mechanical characteristic and heat resistance is obtained. The smaller the average number of phenolic hydroxyl groups, the better. It may be 0, but from the viewpoint of the efficiency of modifying the phenolic hydroxyl group with other functional groups, it is preferably 0.001 or more, more preferably 0.01. That can be the end.

In a preferred embodiment, the PPE is
(A-1) A PPE component having an average number of phenolic hydroxyl groups per molecule of less than 0.5 and a number average molecular weight of 1,000 or more and 8,000 or less, and (A-2) per molecule Including a PPE component having an average phenolic hydroxyl number of 0.5 or more and a number average molecular weight exceeding 8,000, and based on a total mass of 100% by mass of (A-1) and (A-2) The content of (A-1) is 1% by mass or more and less than 40% by mass, and the content of (A-2) is more than 60% by mass and 99% by mass or less.
In this embodiment, the PPE preferably consists essentially of (A-1) and (A-2), more preferably (A-1) and (A-2).
By using the component (A-2), a high glass transition temperature derived from PPE having a large molecular weight can be obtained. In addition, by using the component (A-2) in a preferred embodiment, good adhesiveness derived from the terminal hydroxyl group can be obtained, and the advantages of excellent heat resistance, mechanical properties, and adhesiveness can be obtained.
The average number of phenolic hydroxyl groups per molecule of the component (A-2) is preferably 0.5 or more, more preferably 0.8 or more, more preferably from the viewpoint of realizing good adhesiveness. 1.6 or more. Although it is preferable in terms of obtaining the above effect that the average number of phenolic hydroxyl groups is large, the water absorption of the cured product composite containing the cured product of the curable resin composition and the substrate is prevented from being increased, or From the viewpoint of preventing increase in dielectric constant and dielectric loss tangent, it is preferably 2 or less, more preferably 1.85 or less, and still more preferably 1.6 or less.

A preferred range of the number average molecular weight of the component (A-2) is more than 8,000 and 40,000 or less, a more preferred range is 9,500 or more and 28,000 or less, and a more preferred range is 10,000 or more and 20 or less. , 000 or less. When the number average molecular weight is more than 8,000, a high glass transition temperature is obtained, so that a cured product having excellent heat resistance and mechanical properties is obtained. On the other hand, when the number average molecular weight is 40,000 or less, the melt viscosity at a normal press molding temperature is kept low, and good moldability is obtained, which is preferable.
The content of (A-2) on the basis of a total of 100% by mass of (A-1) and (A-2) is preferably 60% by mass or more from the viewpoint of realizing a high glass transition temperature and good adhesiveness. More preferably, it is more than 60% by mass, more preferably 70% by mass or more, and further preferably 75% by mass or more, from the viewpoint of reducing the melt viscosity of the curable resin composition at the time of molding and obtaining good moldability. Therefore, it is preferably 99% by mass or less, more preferably 98.8% by mass or less, and still more preferably 98.5% by mass or less.

Moreover, PPE contained in the dispersion liquid containing the resin composition containing the PPE particles of the present invention and a solvent can be a reaction product of PPE and an unsaturated carboxylic acid or acid anhydride. Because PPE is a reaction product of PPE and unsaturated carboxylic acid or acid anhydride, crystallization of PPE in a solvent can be delayed, and a dispersion can be prepared at a lower temperature. Since it can be set as a highly concentrated PPE dispersion liquid, it is preferable.
Examples of the unsaturated carboxylic acid or acid anhydride include acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, glutaconic anhydride, citraconic anhydride, and the like. The reaction is carried out by heating PPE and unsaturated carboxylic acid or acid anhydride in the temperature range of 100 ° C to 390 ° C. At this time, a radical initiator may coexist. Although both the solution method and the melt mixing method can be used, the melt mixing method using an extruder or the like can be performed more easily and is suitable for the purpose of the present invention. The ratio of unsaturated carboxylic acid or acid anhydride is 0.01 parts by weight or more and 5.0 parts by weight or less, preferably 0.1 parts by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of PPE.

In addition, the composition of this embodiment preferably includes various components described in relation to some embodiments of the present invention, such as reaction initiators, flame retardants, other resins, and other additives in the same manner as these embodiments. Can be blended. Such formulations are also encompassed by the present disclosure. Moreover, a varnish, a prepreg, and a printed wiring board can be preferably formed in the same manner as described with respect to another embodiment of the present invention using the composition of the present embodiment.
In another embodiment of the present invention, the curable resin composition containing the PPE particles (A) described above further contains a crosslinkable curable resin, for example, a monomer (C) having two or more vinyl groups in the molecule. Provide prepreg. The curable resin composition is preferably 5 to 95 mass parts of the crosslinkable curable resin (C) with respect to 100 parts by mass in total of the PPE component (A + B) and the crosslinkable curable resin (C) in the prepreg. Parts, more preferably 10-80 parts by mass, still more preferably 10-70 parts by mass, and still more preferably 20-70 parts by mass. When the amount of the monomer (C) is 5 parts by mass or more, it is preferable in terms of good moldability, and when it is 95 parts by mass or less, it is preferable in that a cured product having a low dielectric constant and dielectric loss tangent can be formed.

As the crosslinkable curable resin, a monomer having two or more vinyl groups in the molecule is suitable, and triallyl isocyanurate (TAIC), triallyl cyanurate, triallylamine, triallyl mesate, divinylbenzene, divinyl Naphthalene, divinylbiphenyl and the like can be mentioned, and among them, TAIC having good compatibility with polyphenylene ether is preferable.
The curable resin composition included in this embodiment preferably further includes a crosslinkable curable resin (C) and a (reaction) initiator (D).
As the initiator (D), any initiator having the ability to promote a polymerization reaction of a vinyl monomer can be used. For example, benzoyl peroxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-di Hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butyl peroxide, t-butylcumyl peroxide, α, α'-bis (t- Butylperoxy-m-isopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, di-t-butylperoxyisophthalate, t-butylperoxy Benzoate, 2,2-bis (t-butylperoxy) butane, 2,2-bis (t-butylperoxy) octane, 2,5- Methyl-2,5-di (benzoyl peroxy) hexane, di (trimethylsilyl) peroxide, peroxides such as trimethylsilyl triphenylsilyl peroxide. A radical generator such as 2,3-dimethyl-2,3-diphenylbutane can also be used as a reaction initiator. Among them, 2,5-dimethyl-2,5-di (t-butylperoxy) is preferable from the viewpoint of obtaining a cured product having excellent heat resistance and mechanical properties and having a lower dielectric constant and dielectric loss tangent. Hexin-3, α, α′-bis (t-butylperoxy-m-isopropyl) benzene and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane are preferred.

The content of the initiator (D) is preferably 0.5 parts by mass or more from the viewpoint of increasing the reaction rate with respect to the total of 100 parts by mass of the PPE component (A + B) and the monomer (C) in the prepreg. Preferably it is 1 part by mass or more, more preferably 1.5 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass, from the viewpoint that the dielectric constant and dielectric loss tangent of the resulting cured product can be kept low. Part or less, more preferably 7 parts by weight or less.
In a preferred embodiment, the content of the crosslinkable curable resin (C) is 10 parts by mass or more and 70 parts by mass or less with respect to a total of 100 parts by mass of the PPE component (A + B) and the monomer (C) in the prepreg, and The content of the initiator (D) is 1 part by mass or more and 10 parts by mass or less.

  The curable resin composition of the present invention may further contain other resins (for example, thermoplastic resins, curable resins, etc.). Thermoplastic resins include ethylene, propylene, butadiene, isoprene, styrene, divinylbenzene, methacrylic acid, acrylic acid, methacrylic ester, acrylic ester, vinyl chloride, acrylonitrile, maleic anhydride, vinyl acetate, ethylene tetrafluoride, etc. Examples thereof include homopolymers of vinyl compounds and copolymers of two or more vinyl compounds, and polyamides, polyimides, polycarbonates, polyesters, polyacetals, polyphenylene sulfides, polyethylene glycols, and the like. Among these, a styrene homopolymer, a styrene-butadiene copolymer, and a styrene-ethylene-butadiene copolymer can be preferably used from the viewpoints of solubility of the curable resin composition in a solvent and moldability. Examples of the curable resin include phenol resins, epoxy resins, and cyanate esters. The thermoplastic resin and curable resin may be modified with a functional compound such as an acid anhydride, an epoxy compound, or an amine. The amount of such another resin used is preferably 10 to 90 parts by mass, more preferably 20 to 70 parts by mass with respect to a total of 100 parts by mass of the PPE (A) and the monomer (C). .

The curable resin composition according to the present invention may further contain an appropriate additive depending on the purpose. Examples of the additive include a flame retardant, a heat stabilizer, an antioxidant, a UV absorber, a surfactant, a lubricant, a filler, and a polymer additive.
In particular, when the curable resin composition of the present invention further contains a flame retardant, the good moldability, water absorption resistance, solder heat resistance, and adhesiveness of the present invention (for example, peel strength between layers in a multilayer board, or In addition to the advantage that a printed wiring board having excellent peel strength between a cured product and copper foil or the like can be obtained, it is preferable in that flame retardancy can be imparted.

The flame retardant is not particularly limited as long as it has a function of hindering the combustion mechanism. Inorganic flame retardants such as antimony trioxide, aluminum hydroxide, magnesium hydroxide, zinc borate, hexabromobenzene, decabromobenzene And aromatic bromine compounds such as phenylethane, 4,4-diphbromophenyl, and ethylenebistetrabromophthalimide. Of these, decabromojephenylethane is preferred from the viewpoint of keeping the dielectric constant and dielectric loss tangent of the cured product low.
The amount of flame retardant used varies depending on the flame retardant used, and is not particularly limited, but from the viewpoint of maintaining flame retardancy at the UL standard 94V-0 level, a total of 100 PPE (A) and monomer (C). Preferably it is 5 mass parts or more with respect to a mass part, More preferably, it is 10 mass parts or more, More preferably, it is 15 mass parts or more. Moreover, from a viewpoint which can maintain the dielectric constant and dielectric loss tangent of the hardened | cured material small, Preferably it is 50 mass parts or less, More preferably, it is 45 mass parts or less, More preferably, it is 40 mass parts or less.

A varnish containing the curable resin composition described above is also disclosed. The varnish can be formed by dissolving or dispersing the curable resin composition of the present invention in a solvent. After impregnating the varnish with a base material such as glass cloth, the solvent content is removed by drying, whereby a prepreg suitable as a material for the insulating layer of the substrate material can be produced.
In general, examples of the solvent used for the varnish include toluene, xylene, methyl ethyl ketone, and acetone. These solvents can be used alone or in combination of two or more. For example, you may combine 1 or more types of said various solvents, and alcohols, such as methanol. The ratio of the curable resin composition in the varnish is 5 to 95 parts by mass with respect to 100 parts by mass of the varnish from the viewpoint of satisfactorily controlling the varnish impregnation property to the substrate and the resin adhesion amount to the substrate. It is preferable that it is 20 to 80 parts by mass.

The prepreg of the present invention is typically a printed circuit board prepreg. A typical prepreg is a composite of a curable resin composition and a substrate obtained by impregnating a varnish containing the curable resin composition into a substrate and then volatilizing the solvent with a hot air dryer or the like. Is the body. As the base material, various glass cloths such as roving cloth, cloth, chopped mat, and surfacing mat; asbestos cloth, metal fiber cloth, and other synthetic or natural inorganic fiber cloth; wholly aromatic polyamide fiber, wholly aromatic polyester fiber Woven or non-woven fabrics obtained from liquid crystal fibers such as polybenzoxazole fibers; natural fiber fabrics such as cotton cloth, linen cloth and felt; carbon fiber cloth, kraft paper, cotton paper, cloth obtained from paper-glass mixed yarn, etc. Natural cellulose base materials; polytetrafluoroethylene porous films; etc. can be used alone or in combination of two or more.
The proportion of the curable resin composition in the prepreg is preferably 30 to 80 parts by mass, more preferably 40 to 70 parts by mass with respect to 100 parts by mass of the total amount of prepreg. When the ratio is 30 parts by mass or more, excellent insulation reliability is obtained when the prepreg is used for forming an electronic substrate, for example. When the prepreg is 80 parts by mass or less, for example, the obtained electronic substrate has a flexural modulus. Excellent mechanical properties.

[Preparation method of prepreg composed of a curable resin composition containing PPE particles (A) and a substrate]
A prepreg composed of a curable resin composition containing the PPE particles (A) of the present invention and a substrate is particularly limited if the PPE particles (A) and PPE (B) contained in the prepreg satisfy the requirements of the present invention. Although not necessarily obtained, for example, it is obtained by a method of impregnating a base material with a varnish in which PPE particles (A) are dispersed and drying and removing the solvent.
As a method for obtaining a varnish in which PPE particles (A) are dispersed, there is no particular limitation as long as the PPE particles (A) and PPE (B) contained in the obtained prepreg satisfy the requirements of the present invention, A method of obtaining a varnish by adding other components after obtaining a dispersion of PPE particles (A) is mentioned.
As a method for obtaining such a dispersion of PPE particles (A), for example, a method in which PPE is added to a non-halogen solvent, heated and dissolved, and then the temperature is lowered (hereinafter also referred to as “crystal dispersion method”). Can be mentioned.
The particle size of the PPE particles (A), the PPE content ratio, the PPE molecular weight, and the weight ratio of the PPE particles (A) and PPE (B) present in the prepreg of the present invention are, for example, in the “crystal dispersion method” described below. It can be adjusted by changing the concentration of PPE, the molecular weight of PPE, the type of functional group at the molecular end, the presence and amount of coexisting substances, the temperature drop rate, the stirring rate, and the like.

[Crystal dispersion method]
In a method in which PPE is added to a non-halogen solvent, dissolved by heating, and then the temperature is lowered to obtain PPE crystal particles, a PPE solution containing 70 mass% or more of PPE in the solid content is used. To obtain particles. The content of particles having a major axis of 3 μm or more and 20 μm or less is preferably 60% or more from the viewpoint of obtaining a viscosity suitable for coating. Further, it is preferable that the ratio of the major axis / minor axis of the particles is in the range of 1.0 or more and 1.2 or less, because a viscosity suitable for coating is obtained, and fluidity is easily obtained. It is also preferable in that the PPE particle concentration in the inside can be increased.
In addition, it is preferable that the ratio of PPE in the PPE solution with respect to the dissolved component is high, because the PPE concentration in the PPE particles can be increased and PPE particles that satisfy the requirements of the present invention can be easily obtained. In addition to PPE, the PPE solution includes a block comprising a polystyrene block, a polymer block A mainly composed of one kind of vinyl aromatic compound, and a polymer block B mainly composed of at least one kind of conjugated diene compound. An additive such as a hydrogenated block copolymer obtained by hydrogenating the copolymer may also be included. In addition, it is better that the PPE solution does not contain a component having a melting point of 30 ° C. or higher because a PPE crystal dispersion having a stable and reproducible fluidity can be obtained.
The temperature drop is preferably performed in a tank provided with a stirring blade. The PPE particle dispersion is produced by lowering the temperature of the PPE dissolved in the non-halogen solvent while stirring. At this time, when the temperature becomes 10 ° C. or more higher than the temperature at which the PPE crystal particles start to precipitate, stirring is preferably performed at a blade tip speed of 3 m / s or less in order to prevent aggregation of the particles and thickening of the dispersion. In addition, the temperature drop may be in a stationary state from the viewpoint of easily controlling the obtained PPE particles into a large spherical shape and increasing the fluidity of the dispersion or increasing the PPE content.

In addition, the temperature lowering temperature should be close to the temperature at which the varnish is impregnated into the base material. For example, when the coating temperature is α ° C., by setting the temperature to α-15 ° C. or higher and α + 10 ° C. or lower, The mass ratio of PPE particles (A) and PPE (B) is easy to control, and a stable prepreg is obtained, which is preferable. A more preferable range of the temperature lowering arrival temperature is α-10 ° C. or more and α + 5 ° C. or less, a more preferable temperature range α-5 ° C. or more and α + 4 ° C. or less, and a most preferable temperature range is α−3 ° C. or more and α + 3 ° C. or less.
As a temperature condition in the case of producing a varnish from the resin dispersion obtained by this method, the PPE particles (A) may be carried out at a temperature between the temperature lowering arrival temperature and the coating temperature at the time of resin dispersion production. However, there is no particular limitation as long as the mass ratio between the PPE particles (A) and the PPE (B) can be controlled.
When a resin varnish is produced by adding other components to the resin dispersion, the addition rate of the components is 0.6 parts by weight per minute based on 100 parts by weight of the total PPE content in the dispersion. It is preferable to add at the following speed in terms of preventing resin aggregation.

  As a solvent used in the dispersion, the solubility of PPE at a temperature of 25 ° C. is preferably 3% by mass or more and 20% by mass or less. More preferably, the solubility of PPE at a temperature of 80 ° C. is 20% by mass or more, preferably 30% by mass or more. There is no particular limitation as long as the above PE solubility characteristics are satisfied, and one or a mixture of two or more may be used. Preferable solvents include aromatic organic solvents such as benzene, toluene and xylene, ketones such as cyclohexanone, methyl ethyl ketone and methyl isobutyl ketone, and alcohols such as methanol, ethanol and butanol.

By using the curable resin composition according to the present invention described above, a laminate in which a cured product composite including a cured product of the curable resin composition and a substrate and a metal foil are laminated can be formed. The laminate is preferably one in which the cured product composite and the metal foil are in close contact with each other, and is suitably used as a material for an electronic substrate. As the metal foil, for example, an aluminum foil and a copper foil can be used, and among them, the copper foil is preferable because of its low electric resistance. The cured product composite to be combined with the metal foil may be one sheet or a plurality of sheets, and the metal foil is overlapped on one side or both sides of the composite to be processed into a laminate according to the use. As a manufacturing method of a laminated board, for example, a composite (for example, the above-mentioned prepreg) composed of a curable resin composition and a substrate is formed, and this is overlapped with a metal foil, and then a curable resin composition. The method of obtaining the laminated board on which the hardened | cured material laminated body and metal foil are laminated | stacked by hardening | curing is mentioned. One particularly preferred application of the laminate is a printed wiring board.
Another aspect of the present invention provides a printed wiring board comprising a cured product of the curable resin composition of the present invention described above and a base material. The printed wiring board of the present invention can typically be formed by a method of pressure and heat molding using the prepreg of the present invention described above. Examples of the substrate include the same materials as described above with respect to the prepreg. Since the printed wiring board of the present invention is formed using the curable resin composition as described above, it can have excellent insulation reliability and mechanical properties.

Hereinafter, the present embodiment will be specifically described by way of examples. However, the present embodiment is not limited to the following examples.
The physical properties in the following examples, comparative examples and test examples were measured by the following methods.
(1) Number average molecular weight of PPE Using gel permeation chromatography analysis (GPC), the number average molecular weight was determined by comparison with the elution time of standard polystyrene having a known molecular weight.
HLC-8220GPC (manufactured by Tosoh Corporation) is used as a measuring apparatus, and measurement is performed under the conditions of column: Shodex LF-804 × 2 (manufactured by Showa Denko KK), eluent: chloroform at 50 ° C., detector: RI. went.

(2) Average number of phenolic hydroxyl groups per molecule of PPE Using the number of phenolic hydroxyl groups contained in PPE determined from the absorbance and the number of PPE molecules determined from the average molecular weight, the average number of phenolic hydroxyl groups per molecule was determined. It was.
First, collection of polymer papers, vol. 51, no. 7 (1994), in accordance with the method described on page 480, from a value obtained by measuring an absorbance change at a wavelength of 318 nm of a sample obtained by adding a tetramethylammonium hydroxide solution to a methylene chloride solution of PPE with an ultraviolet-visible spectrophotometer. The number of hydroxyl groups was determined.
Separately, the number average molecular weight of PPE was determined by gel permeation chromatography (GPC) according to (1) above, and the number of PPE molecules was determined using this value. From these values, the average number of hydroxyl groups per PPE molecule was calculated according to the following formula.
Average number of phenolic hydroxyl groups per molecule = number of hydroxyl groups / number average number of molecules

(3) Dielectric constant and dielectric loss tangent of laminated plate The dielectric constant and dielectric loss tangent of the laminated plate at 1 GHz were measured using an impedance analyzer.
Using an impedance analyzer (4291B op.002 with 16453A, 16454A, manufactured by Agilent Technologies) as a measuring device, measurement is performed under the conditions of test piece thickness: about 2 mm, voltage: 100 mV, frequency: 1 mm Hz to 1.8 GHz, and 100 sweeps. It calculated | required as an average value of times.

(4) Water Absorption Rate of Laminate Plate The laminate plate was subjected to a water absorption acceleration test, and the water absorption rate was determined from the increased mass.
The laminate was cut into 50 mm squares to produce test pieces. After the test piece was dried at 130 ° C. for 30 minutes, the mass was measured to obtain the mass (g) before the acceleration test. Subsequently, the mass after the acceleration test was performed under the conditions of temperature: 121 ° C., pressure: 2 atm, and time: 4 hours, and the mass (g) after the acceleration test was measured.
Using the mass (g) before the acceleration test and the mass (g) after the acceleration test, the water absorption was calculated by the following formula, and the average value of the measured values of the four test pieces was obtained.
Water absorption (mass%) = (mass before acceleration test−mass after acceleration test) / mass before acceleration test × 100

(5) Solder heat resistance after water absorption test of laminated board A solder heat resistance test was performed at 288 ° C and 260 ° C using the laminated board after measuring the water absorption rate described in (4) above. The laminated board after the water absorption acceleration test was immersed in a solder bath at 288 ° C. or 260 ° C. for 20 seconds, and visually observed. A laminated board in which neither swelling, peeling or whitening was confirmed even when immersed in a solder bath at 288 ° C. was evaluated as “solder heat resistance 288 ° C.”. In addition, any one or more of swelling, peeling and whitening occurred by immersion in a solder bath at 288 ° C., but neither swelling nor peeling or whitening was confirmed even when immersed in a solder bath at 260 ° C. The laminated board was evaluated as “solder heat resistance 260 ° C.”. Moreover, the laminated board which generate | occur | produced any one or more of a swelling, peeling, and whitening by immersion in a 260 degreeC solder bath was evaluated as "failed."

(6) Copper foil peel strength of laminate (Peel strength N / mm)
The stress when peeling the copper foil of the copper clad laminate at a constant speed was measured. A copper-clad laminate using a 35 μm copper foil (GTS-MP foil, manufactured by Furukawa Electric Co., Ltd.) produced by the method described below was cut into a size of 15 mm wide × 150 mm long, and an autograph (AG-5000D, Shimadzu Corporation) was used to measure the average value of the load when the copper foil was peeled off at a speed of 50 mm / min at an angle of 90 ° C. with respect to the removal surface, and the average value of five measurements was obtained. .

(7) Powder removal and peeling of prepreg When the prepreg was bent at 180 °, it was examined and evaluated whether resin powder falling or resin peeling occurred. First, the prepreg was cut out to a size of 200 mm × 300 mm using a cutter blade. Next, the prepreg was bent at 180 ° so that the two long sides of the rectangle overlapped, and then returned to its original state. Next, the prepreg was bent at 180 ° so that the two sides of the short side of the rectangle overlapped, and then returned to its original state. In the above-described series of prepreg handling, those that had no problems such as falling off of the resin powder or peeling of the resin layer were evaluated as “pass”. On the other hand, the case where the resin powder was severely removed was evaluated as “failed / resin powder fall”, and the case where the resin layer was severely peeled was evaluated as “failed / resin peeled”.

(8) Maximum major axis of PPE particles (A) insoluble in a mixed solvent of toluene and methanol with a mass ratio of 95: 5 As described above, the maximum major axis of the PPE particles (A) was determined.

(9) Ratio of the number of PPE particles (A) having a major axis of 3 μm or more and 20 μm or less to the total number of PPE particles (A) insoluble in a mixed solvent of toluene and methanol having a mass ratio of 95: 5 Asked.

(10) PPE content ratio in PPE particles (A) As described above, the above ratio was determined.

(11) Number average molecular weight of PPE contained in PPE particles (A) As described above, the molecular weight was determined.

(12) Mass ratio of PPE (A) insoluble in a mixed solvent of toluene and methanol having a mass ratio of 95: 5 and PPE (B) soluble in the same solvent As described above, the mass ratio was determined.

(13) Number average molecular weight of PPE (B) The molecular weight was determined as described above.

(14) Viscosity of dispersion liquid B-type viscometer, rotor No. 3 was used, and the viscosity was measured under the conditions of 25 ° C., 30 rpm, and 30 seconds.

(15) Dispersion stability of dispersion liquid 35 g of the dispersion liquid was placed in a glass 50 ml sample tube and allowed to stand in a thermostatic chamber at 23 ° C. for 3 days. Those that did not separate due to sedimentation of PPE particles and maintained fluidity were evaluated as “pass”. Further, the case where separation due to sedimentation of PE particles or the like occurred was evaluated as “separation”, and the case where there was no fluidity was described as “gelation”.

<Production Example 1: Low molecular weight / benzylated PPE>
A 10 L flask was placed in an oil bath heated to 90 ° C., and nitrogen gas was introduced into the flask at a rate of 30 ml per minute. Thereafter, the operation was always performed under a nitrogen gas stream. Here, 1000 g of PPE and 3000 g of toluene were added and dissolved by stirring. Further, a solution obtained by dissolving 80 g of bisphenol A in 350 g of methanol was added to the flask with stirring. After stirring for 5 minutes, 3 ml of 6 mass% cobalt naphthenate mineral spirit solution was added with a syringe, and stirring was continued for 5 minutes. Subsequently, 1125 g of toluene was added to 375 g of the benzoyl peroxide solution, and a solution diluted so that the benzoyl peroxide concentration was 10% by mass was placed in a dropping funnel and dropped into the flask over 2 hours. After completion of the dropwise addition, heating and stirring were further continued for 2 hours to obtain a reaction solution containing a low molecular weight PPE. The number average molecular weight of the obtained low molecular weight PPE was 2,800, and the average number of phenolic hydroxyl groups per molecule was 1.96.

  Next, the temperature of the reaction solution containing the low molecular weight PPE was lowered to 50 ° C., an aqueous solution in which 340 g of sodium hydroxide was dissolved in 3050 g of ion-exchanged water and 31 g of tetrabutylammonium iodide were added and stirred for 5 minutes. Subsequently, 1070 g of benzyl chloride was added and stirring was continued at a temperature of 50 ° C. for 4 hours to obtain a reaction solution containing low molecular weight / benzylated PPE. The reaction solution was allowed to stand and the two layers were separated, and then the lower tank was removed. Further, 1000 g of water was added, stirred, allowed to stand, and again separated into two tanks, and then the lower tank was removed. Next, 200 g of methanol was added, and the mixture was stirred and allowed to stand in the same manner to separate into two layers, and then the upper layer was removed. Further, 100 g of methanol was added, and similarly stirred and allowed to stand to separate into two layers, and then the lower layer was recovered to obtain a reaction solution containing a low molecular weight / benzylated PPE. A large amount of methanol was added thereto to precipitate low molecular weight / benzylated PPE, which was filtered and dried to obtain low molecular weight / benzylated PPE. The number average molecular weight of the obtained low molecular weight / benzylated PPE was 3,000, and the average number of phenolic hydroxyl groups per molecule was 0.01.

<Production Example 2: Reaction product of PPE and maleic anhydride>
100 parts by weight of PPE (S202A, manufactured by Asahi Kasei Chemicals, number average molecular weight 18,000, average number of phenolic hydroxyl groups 1.84 per molecule), 1.5 parts by weight of maleic anhydride, and 2,5-dimethyl-2 After dry blending 1.0 parts by weight of 5-di (t-butylperoxy) hexane (Perhexa 25B, manufactured by NOF Corporation) at room temperature, it is extruded by a twin screw extruder under conditions of a cylinder temperature of 300 ° C. and a screw rotation speed of 230 rpm. A reaction product of PPE and maleic anhydride was obtained. The number average molecular weight of the reaction product of the obtained PPE and maleic anhydride was 17,000, and the average number of phenolic hydroxyl groups per molecule was 0.95.

<Example 1>
111 parts by weight of toluene was placed in a separable flask and heated to 80 ° C. PPE (S202A, manufactured by Asahi Kasei Chemicals, number average molecular weight 18,000, average number of phenolic hydroxyl groups 1.84 per molecule) 53.3 parts, styrene elastomer (SOE L606, manufactured by Asahi Kasei Chemicals) 3.6 parts by weight And stirred at 80 ° C. for 2 hours to dissolve the PPE and the styrene elastomer. Stirring was stopped and the temperature was lowered to 25 ° C. over 5 hours to obtain a dispersion A of PPE particles. The PPE particle dispersion A had moderate fluidity and dispersion stability, and had a viscosity of 512 mPa · s. In addition, PPE particle dispersion A contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 12 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 90%, and the PPE content was 91% by mass.
In the obtained PPE dispersion A, triallyl isocyanurate (Nihon Kasei) 21.3 parts by weight, α, α'-bis (t-butylperoxy-m-isopropyl) benzene (Perbutyl P, manufactured by NOF Corporation) After adding 2.3 parts by weight and stirring uniformly, 15.9 parts of decabromodiphenylethane (SAYTEX 8010, manufactured by Albemarle Japan) and 24.6 parts by weight of silica filler (spherical silica, manufactured by Tatsumori) were added and stirred uniformly. Thus, varnish A for coating was obtained.
Next, the coating varnish A was impregnated into an E glass glass cloth (2116 style, manufactured by Asahi Shovel) with a thickness of about 0.1 m, and after removing excess varnish with a slit, the solvent was removed by drying. A prepreg A having a resin content of 60% by mass was obtained. The prepreg A was excellent in handleability with no powder falling off or peeling off of the resin.

<Example 2>
158 parts by weight of toluene was placed in a separable flask and heated to 80 ° C. Add 53.3 parts of PPE (S202A, manufactured by Asahi Kasei Chemicals, number average molecular weight 18,000, average number of phenolic hydroxyl groups per molecule 1.84), 1.5 parts by weight of polystyrene (650, manufactured by PS Japan), The mixture was stirred at 80 ° C. for 2 hours to dissolve the PPE and polystyrene. Stirring was stopped and the temperature was lowered to 25 ° C. over 5 hours to obtain a dispersion B of PPE particles.
The PPE particle dispersion B had moderate fluidity and dispersion stability, and had a viscosity of 602 mPa · s. In addition, PPE particle dispersion A contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 12 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 68%, and the PPE content was 87% by mass.
To the obtained PPE particle dispersion B, triallyl isocyanurate (Nippon Kasei) 22.8 parts by weight, α, α'-bis (t-butylperoxy-m-isopropyl) benzene (perbutyl P, manufactured by NOF Corporation) ) After adding 1.5 parts by weight and stirring uniformly, 19.8 parts of decabromodiphenylethane (SAYTEX8010, manufactured by Albemarle Japan) was added and stirred uniformly to obtain varnish B for coating.
Next, the coating varnish B was impregnated into a glass cloth made of E glass (2116 style, manufactured by Asahi Shovel) with a thickness of about 0.1 m, and after removing excess varnish with a slit, the solvent was removed by drying. A prepreg B having a resin content of 60% by mass was obtained. The prepreg B was excellent in handleability, with no powder falling off or peeling off of the resin.

<Example 3>
A dispersion C of PPE particles was obtained in the same manner as in Example 2 except that the temperature drop of the toluene solution of PPE and polystyrene was reduced to 35 ° C. The PPE particle dispersion C had moderate fluidity and dispersion stability, and had a viscosity of 524 mPa · s. In addition, PPE particle dispersion C contains PPE extracted as an insoluble component in a 95: 5 mass ratio of toluene and methanol mixed solvent. As shown in Table 1 below, the maximum major axis is 12 μm, and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 92%, and the polyphenylene ether content was 96% by mass.
Next, a prepreg C having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion C was used. The prepreg C was excellent in handleability, with no powder falling off or peeling off of the resin.

<Example 4>
A dispersion D of PPE particles was obtained in the same manner as in Example 2 except that the amount of toluene was 210 parts by weight and the temperature drop of the toluene solution of PPE and polystyrene was 20 ° C. The PPE particle dispersion D had moderate fluidity and dispersion stability, and had a viscosity of 624 mPa · s. The PPE particle dispersion D contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 13 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 81%, and the PPE content was 90% by mass.
Next, a prepreg D having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion D was used. The prepreg D was excellent in handleability with no resin powder falling off or peeling off.

<Example 5>
A dispersion E of PPE particles was obtained in the same manner as in Example 4 except that the temperature drop of the toluene solution of PPE and polystyrene was reduced to 35 ° C. The PPE particle dispersion E had moderate fluidity and dispersion stability, and had a viscosity of 440 mPa · s. The PPE particle dispersion E contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 12 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 88%, and the PPE content was 100% by mass.
Next, a prepreg E having a resin content of 60% by mass was obtained in the same manner as in Example 4 except that the obtained PPE particle dispersion E was used. The prepreg E was excellent in handleability with no powder falling off or peeling off of the resin.

<Example 6>
In place of PPE used in Example 2, PPE (S201A, manufactured by Asahi Kasei Chemicals, number average molecular weight 25,000, average number of phenolic hydroxyl groups per molecule 1.88) is the same as Example 2 In this way, a dispersion F of PPE particles was obtained. The PPE particle dispersion F had moderate fluidity and dispersion stability, and had a viscosity of 720 mPa · s. The PPE particle dispersion F contains PPE extracted as an insoluble component in a 95: 5 mass ratio of toluene and methanol mixed solvent. As shown in Table 1 below, the maximum major axis is 13 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 85%, and the PPE content was 88% by mass.
Next, a prepreg F having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion F was used. The prepreg F was excellent in handleability with no resin falling off or peeling off.

<Example 7>
In place of PPE used in Example 2, PPE (S203A, manufactured by Asahi Kasei Chemicals Corporation, number average molecular weight 10,000, average number of phenolic hydroxyl groups per molecule 1.80) was the same as Example 2 In this way, a dispersion G of PPE particles was obtained. The PPE particle dispersion G had moderate fluidity and dispersion stability, and had a viscosity of 520 mPa · s. In addition, PPE particle dispersion G contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 10 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 92%, and the PPE content was 97% by mass.
Next, a prepreg G having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion G was used. The prepreg G was excellent in handleability, with no powder falling off or peeling off of the resin.

<Example 8>
A dispersion H of PPE particles was obtained in the same manner as in Example 2 except that a reaction product of PPE and maleic anhydride (see Production Example 3) was used instead of PPE used in Example 2. The PPE particle dispersion H had moderate fluidity and dispersion stability, and had a viscosity of 464 mPa · s. The PPE particle dispersion H contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 14 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 97%, and the PPE content was 97% by mass.
Next, a prepreg H having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion G was used. The prepreg H was excellent in handleability with no powder falling off or peeling of the resin.

<Example 9>
In place of 53.3 parts of PPE used in Example 2, the same method as in Example 2 except that 42.6 parts by weight of PPE and 10.7 parts by weight of low molecular weight / benzylated PPE (see Production Example 1) were used. Thus, a dispersion I of PPE particles was obtained. The PPE particle dispersion H had moderate fluidity and dispersion stability, and had a viscosity of 458 mPa · s. Further, PPE particle dispersion I contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 14 μm and the major axis is 3 μm to 3 μm. The proportion of 20 μm was 91%, and the PPE content was 96% by mass.
Next, a prepreg I having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion G was used. The prepreg I was excellent in handleability with no resin falling off or peeling off.

<Comparative Example 1>
150 parts by weight of toluene was placed in a separable flask and heated to 80 ° C. PPE (S202A, manufactured by Asahi Kasei Chemicals, number average molecular weight 18,000, average number of phenolic hydroxyl groups 1.84 per molecule) 53.3 parts, polystyrene (650, manufactured by PS Japan) 2.6 parts by weight, triallyl 22.8 parts by weight of isocyanurate (manufactured by Nippon Kasei) was added and dissolved by stirring at 80 ° C. for 2 hours. Stirring was stopped and the temperature was lowered to 25 ° C. over 5 hours to obtain a dispersion J of PPE particles. The PPE particle dispersion J became grease-like due to swelling and gelation, and showed no fluidity, so that it could not be used for subsequent varnish preparation and prepreg coating. The PPE particle dispersion J contains PPE extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 12, and the ratio of the major axis is 3 μm to 20 μm. Was 44% and the PPE content was 48% by mass.

<Comparative example 2>
233 parts by weight of toluene was placed in a separable flask and heated to 80 ° C. PPE (S202A, manufactured by Asahi Kasei Chemicals, number average molecular weight 18,000, average number of phenolic hydroxyl groups 1.84 per molecule) 53.3 parts, polystyrene (650, manufactured by PS Japan) 2.6 parts by weight, triallyl 22.8 parts by weight of isocyanurate (manufactured by Nippon Kasei) was added and dissolved by stirring at 80 ° C. for 2 hours. Stirring was stopped and the temperature was lowered to 25 ° C. over 5 hours to obtain a dispersion K of PPE particles. The PPE particle dispersion K had a high viscosity of 1180 mPa · s, but exhibited fluidity, so that it could be used for subsequent varnish preparation and prepreg coating. The PPE particle dispersion K contains PPE that is extracted as an insoluble component in a toluene / methanol mixed solvent having a mass ratio of 95: 5. As shown in Table 1 below, the maximum major axis is 11, and the ratio of the major axis is 3 μm to 20 μm. Was 55% and the PPE content was 57% by mass.
Next, a prepreg K having a resin content of 60% by mass was obtained in the same manner as in Example 2 except that the obtained PPE particle dispersion K was used. In the prepreg K, resin powder was observed.

<Comparative Example 3>
A dispersion L containing PPE particles was obtained in the same manner as in Example 2 except that the temperature drop of the toluene solution of PPE and polystyrene was changed to 20 ° C. When the dispersion L was observed with an optical microscope, many very small particles were present. Dispersion L became grease-like due to swelling and gelation of the particles, did not exhibit fluidity, and could not be used for subsequent varnish preparation and prepreg coating.
As shown in Table 1 below, the PPE particles extracted as an insoluble in a toluene / methanol mixed solvent having a mass ratio of 95: 5 of the PPE particle dispersion L have a maximum major axis of 5, and a ratio of major axis of 3 μm to 20 μm is 16. %, PPE content was 89% by mass, which was very small.

<Comparative example 4>
A dispersion M containing PPE particles was obtained in the same manner as in Example 2 except that the amount of toluene was 111 parts by weight. When the dispersion M was observed with an optical microscope, many very small particles were present. Dispersion M became grease-like due to swelling and gelation of the particles, did not exhibit fluidity, and could not be used for subsequent varnish preparation and prepreg coating.
As shown in Table 1 below, PPE particles extracted as an insoluble in a toluene / methanol mixed solvent having a mass ratio of 95: 5 of the PPE particle dispersion M have a maximum major axis of 6, and a ratio of major axis of 3 μm to 20 μm is 23. %, PPE content was 88% by mass, which was very small.

<Comparative Example 5>
A dispersion N containing PPE particles was obtained in the same manner as in Example 2 except that the amount of toluene was 240 parts by weight and the temperature drop of the toluene solution of PPE and polystyrene was 35 ° C. The PPE particle dispersion N had a viscosity of 210 mPa · s and good fluidity, but was inferior in dispersion stability. In a few hours, the PPE particles settled and the dispersion separated. As shown in Table 1 below, PPE particles extracted as insoluble in a toluene / methanol mixed solvent having a mass ratio of 95: 5 of PPE particle dispersion N have a maximum major axis of 17 and a ratio of major axis of 3 μm to 20 μm is 97. %, PPE content was 98% by mass, which was very large.
Next, triallyl isocyanurate and decabromodiphenylethane were added to the PPE particle dispersion N in the same manner as in Example 2 to obtain a coating varnish N.
Since the coating varnish N was inferior in dispersion stability, stirring was performed until just before coating to make it uniform, and the others were applied in the same manner as in Example 2, but the coating on the glass cloth was attempted. However, only 44% by mass of prepreg was obtained.

<Test example>
A substrate sample was prepared using the prepregs A to I and K obtained in Examples 1 to 9 and Comparative Example 2, and electrical characteristics (dielectric constant, dielectric loss tangent), water absorption, solder heat resistance after water absorption, copper foil peeling The strength was comparatively evaluated.
A sample for evaluating the water absorption rate and the solder heat resistance after the water absorption test was prepared by the following method. Two prepregs obtained in Examples or Comparative Examples were stacked, and a copper foil (GTS-MP foil, manufactured by Furukawa Electric Co., Ltd.) having a thickness of 12 μm was stacked on the top and bottom. Perform vacuum pressing under conditions of pressure 5 kg / cm ² while heating in minutes, and when reaching 130 ° C., perform vacuum pressing under conditions of pressure 30 kg / cm ² while heating at a rate of temperature increase of 3 ° C./min, up to 200 ° C. When the temperature reached 200 ° C., a double-sided copper-clad laminate was obtained by vacuum pressing under the conditions of a pressure of 30 kg / cm ² and a time of 60 minutes. Next, the copper clad laminate was cut into a 100 mm square, the copper foil was removed by etching, and a sample for evaluating the water absorption rate and the solder heat resistance after the water absorption test was obtained.

Moreover, the sample for copper foil peeling strength measurement was produced with the following method. Two prepregs obtained in Examples or Comparative Examples were stacked, and a copper foil having a thickness of 35 μm (GTS-MP foil, manufactured by Furukawa Electric Co., Ltd.) was stacked on the top and bottom. Perform vacuum pressing under conditions of pressure 5 kg / cm ² while heating in minutes, and when reaching 130 ° C., perform vacuum pressing under conditions of pressure 30 kg / cm ² while heating at a rate of temperature increase of 3 ° C./min, up to 200 ° C. When the temperature reached 200 ° C., a double-sided copper-clad laminate was produced by vacuum pressing under the conditions of a pressure of 30 kg / cm ² and a time of 60 minutes. This double-sided copper-clad laminate was used as a sample for measuring the copper foil peel strength.

A sample for measuring dielectric constant and dielectric loss tangent was prepared by the following method. Sixteen prepregs obtained in Examples or Comparative Examples were stacked, vacuum-pressed under the condition of a pressure of 5 kg / cm ² while heating from room temperature at a heating rate of 3 ° C./min, and when reaching 130 ° C., the heating rate was 3 ° C. By performing vacuum pressing under the condition of pressure 30 kg / cm ² while heating at / min, and when reaching 200 ° C., performing vacuum pressing under the conditions of pressure 30 kg / cm ² and time 60 minutes while maintaining the temperature at 200 ° C. A laminate was prepared. The laminate was cut into a 100 mm square and used as a sample for measuring dielectric constant and dielectric loss tangent.
As described above, using prepreg, double-sided copper-clad laminate (copper foil: 12 μm and 35 μm), or laminate, copper foil peel strength, dielectric constant, dielectric loss tangent, water absorption, and solder heat resistance after water absorption Sex was measured. The results are shown in Table 1 below.

As can be seen from Table 1, in each of Examples 1 to 9, the copper foil peel strength was high, the water absorption resistance was good, and the solder heat resistance was also excellent.
On the other hand, Comparative Example 2 in which the viscosity of the dispersion became high was inferior in copper foil peel strength, water absorption resistance, and solder heat resistance as compared with Examples 1-9.

  According to the present invention, since a PPE can be crystallized and the swelling property and particle size of the PPE can be controlled within an appropriate range, a dispersion of a resin composition containing PPE particles having good varnish stability and coating uniformity is provided. Can do. Furthermore, by crystallization of PPE under conditions with a high PPE content and forming crystal particles mainly composed of PPE, the adhesion between the resin component of the prepreg produced using the dispersion and the substrate can be improved. Good and excellent heat resistance and adhesion (for example, peel strength between layers in a multilayer board, or peel strength between a cured product of a curable resin composition and a metal foil such as copper foil) Dispersions from which materials can be obtained, printed wiring prepregs manufactured using the dispersions, and printed wiring boards including cured products of the prepregs can be provided. Therefore, the present invention can be suitably used as a material for a printed wiring board of an electronic device that uses a high frequency band.

Claims (12)

A dispersion containing a resin composition containing polyphenylene ether (PPE) particles and a solvent,
(1) The PPE particles have a major axis size of 30 μm or less,
(2) 60% or more of the total number of PPE particles is a size of 3 μm to 20 μm in major axis,
(3) The PPE particles contain 70% by mass or more of PPE, and (4) the number average molecular weight of the PPE contained in the PPE particles is 8,000 to 40,000.
Said dispersion.   The dispersion containing PPE particles according to claim 1, wherein the solubility of PPE in the solvent at 25 ° C is 3% by mass or more and 20% by mass or less.   The dispersion liquid contains dissolved PPE in addition to the PPE particles, and the mass ratio (A) :( B) of the PPE particles (A) to the dissolved PPE (B) is 85:15 to 30:70. The dispersion according to claim 1 or 2, wherein   The dispersion according to claim 3, wherein the mass ratio (A) :( B) of the PPE particles (A) to the dissolved PPE (B) is 80:20 to 45:55.   The dispersion liquid according to claim 3 or 4, wherein the dissolved PPE (B) has a number average molecular weight of 5,000 to 40,000.   The dispersion according to any one of claims 1 to 5, wherein the PPE component contained in the resin composition is an amount of 10% by mass or more and 70% by mass or less based on the resin composition.   The dispersion liquid according to any one of claims 1 to 6, further comprising a cross-linkable curable resin (C) and an initiator (D).   The dispersion liquid according to claim 7, wherein the crosslinkable curable resin (C) is a monomer having two or more vinyl groups in the molecule.   The dispersion liquid according to claim 7, wherein the crosslinkable curable resin (C) is triallyl isocyanurate (TAIC).   The resin varnish containing the dispersion liquid of any one of Claims 1-9.   The prepreg obtained by apply | coating the varnish containing the dispersion liquid of any one of Claims 1-9 to a base material, and then removing a solvent from the base material with which this dispersion liquid was apply | coated.   A printed wiring board produced using the prepreg obtained in claim 10 as a constituent component.

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