WO2017168732A1

WO2017168732A1 - Resin composition, prepreg, resin sheet and laminate

Info

Publication number: WO2017168732A1
Application number: PCT/JP2016/060851
Authority: WO
Inventors: 信次土川; 高根沢　伸; 慎太郎橋本; 徳彦坂本
Original assignee: 日立化成株式会社
Priority date: 2016-03-31
Filing date: 2016-03-31
Publication date: 2017-10-05
Also published as: JPWO2017168732A1

Abstract

This resin composition contains a carbodiimide compound that has at least one carbodiimide group in each molecule, a curing agent and an inorganic filler. It is preferable that an aromatic carbodiimide compound is contained as the carbodiimide compound. It is preferable that at least one compound selected from the group consisting of carboxylic acids, epoxy compounds, phenol compounds and amines is contained as the curing agent. It is preferable that silica is contained as the inorganic filler.

Description

Resin composition, prepreg, resin sheet and laminate

The present invention relates to a resin composition, a prepreg, a resin sheet, and a laminate.

The thermosetting resin exhibits high heat resistance and dimensional stability due to a unique cross-linked structure contained in the cured product of the thermosetting resin. Therefore, thermosetting resins are widely used in fields such as electronic parts. Among these electronic components, particularly in copper-clad laminates and interlayer insulation materials, high copper foil adhesion and heat resistance as well as good low cure shrinkage and low heat are required due to recent demands for higher density and reliability of wiring. Swellability is required. In addition, due to environmental problems in recent years, mounting of electronic components using lead-free solder and flame resistance using halogen-free are required. For this reason, the thermosetting resin is required to have higher heat resistance and flame retardancy than conventional ones. Furthermore, in order to improve the safety of the product and the working environment, there is a demand for a thermosetting resin composed of components having low toxicity and generating no toxic gas, and a composition thereof.

The cyanate compound, which is a thermosetting resin, is a resin having excellent dielectric properties and flame retardancy. However, when used in an epoxy-curing resin composition, there is a problem that the curing shrinkage rate increases. Furthermore, there is a problem that heat resistance and toughness are insufficient. Moreover, the low thermal expansion required for the next generation was also insufficient.

JP-A-2003-268136, JP-A-2003-73543, and JP-A-2002-285015 disclose resin compositions comprising a cyanate compound and an inorganic filler and exhibiting low thermal expansion. In addition, JP 2002-309085 A and JP 2002-348469 A disclose examples relating to resin compositions containing a cyanate resin and an aralkyl-modified epoxy resin as essential components.

The object of the present invention is to provide a novel resin composition, prepreg, resin sheet and laminate using a carbodiimide compound.

Specific means for achieving the above object are as follows.
<1> A prepreg containing a carbodiimide compound having at least one carbodiimide group in one molecule.

<2> A prepreg having a peak at 2120 ± 5 cm ⁻¹ in an infrared absorption spectrum.

<3> A resin composition containing a carbodiimide compound having at least one carbodiimide group in one molecule, a curing agent, and an inorganic filler.

<4> The resin composition according to <3>, wherein the carbodiimide compound includes an aromatic carbodiimide compound.

<5> The resin composition according to <3> or <4>, wherein the curing agent includes at least one selected from the group consisting of a carboxylic acid, an epoxy compound, a phenol compound, and an amine.

<6> The resin composition according to any one of <3> to <5>, wherein the inorganic filler includes silica.

<7> The resin composition according to any one of <3> to <6>, wherein the inorganic filler includes boehmite type aluminum hydroxide.

<8> The resin composition according to any one of <3> to <7>, wherein the inorganic filler has an average particle size of 5.0 μm or less.

<9> The resin composition according to any one of <3> to <8>, which contains a maleimide compound.

<10> A prepreg having a base material and the resin composition according to any one of <3> to <9> impregnated in the base material.

<11> A resin sheet obtained by molding the resin composition according to any one of <3> to <9> into a sheet shape.

<12> Laminated plate in which the prepregs described in <1>, <2> or <10> are laminated.

According to the present invention, a novel resin composition, prepreg, resin sheet and laminate using a carbodiimide compound are provided.

Hereinafter, embodiments of the resin composition, prepreg, resin sheet, and laminate of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.
In this specification, the term “process” includes a process that is independent of other processes and includes the process if the purpose of the process is achieved even if it cannot be clearly distinguished from the other processes. It is.
In the present specification, numerical values indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content rate or content of each component in the composition is such that when there are a plurality of substances corresponding to each component in the composition, the plurality of kinds present in the composition unless otherwise specified. It means the total content or content of substances.
In this specification, the particle size of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In this specification, the term “layer” refers to the case where the layer is formed only in a part of the region in addition to the case where the layer is formed over the entire region. Is also included.
In this specification, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.

<Prepreg>
-First embodiment-
The prepreg of the first embodiment contains a carbodiimide compound having at least one carbodiimide group in one molecule.
The carbodiimide compound undergoes a curing reaction in the presence of a curing agent such as a carboxylic acid, an epoxy compound, a phenol compound, or an amine to form a cured product. Moreover, carbodiimide groups couple | bond together by carbodiimide group reacting and forming a dimer or a trimer. Thus, the carbodiimide compound provides a cured product through various reactions. The prepreg of the first embodiment contains a carbodiimide compound having at least one carbodiimide group in one molecule, and can provide a cured product by a curing reaction of the carbodiimide group.
The carbodiimide compound contained in the prepreg of the first embodiment is preferably a carbodiimide compound having at least two carbodiimide groups in one molecule from the viewpoint of obtaining a strong cured product.
The carbodiimide compound used in the first embodiment will be described in detail in the section of the resin composition of the present embodiment described later.

-Second embodiment-
The prepreg of the second embodiment has a peak at 2120 ± 5 cm ⁻¹ in the infrared absorption spectrum. The peak at 2120 ± 5 cm ⁻¹ in the infrared absorption spectrum is a peak derived from a carbodiimide group. The peak at 2120 ± 5 cm ⁻¹ in the infrared absorption spectrum observed in the prepreg of the second embodiment may be a peak derived from a carbodiimide group contained in the carbodiimide compound before curing, or a part of the carbodiimide compound may be It may be a peak derived from a carbodiimide group contained in a semi-cured product in a cured state (that is, B stage). By specifying the prepreg at the position of the peak of the infrared absorption spectrum, it can be easily specified whether the carbodiimide compound or a semi-cured product thereof is contained in the prepreg.
In this specification, the term “B stage” is defined by JIS K6900: 1994.

In this embodiment, the infrared absorption spectrum can be measured using infrared spectroscopy. For example, BioRad Laboratories, FT-IR FTS6000 model is used as an infrared spectrometer, and the number of integrations is measured by 256 using the KBr tablet method, liquid film method, or the like.

-Third embodiment-
The prepreg of the third embodiment has a base material and a resin composition of the present embodiment described later impregnated in the base material.
The prepreg of the third embodiment can be formed by impregnating a base material with a resin composition of the present embodiment described later.
The prepreg of the third embodiment can also be produced by impregnating the resin composition of the present embodiment into a substrate and semi-curing (B-stage) the resin composition by heating or the like. As the base material used in the third embodiment, known materials used in various laminated sheets for electrical insulating materials can be used.

The average thickness of the prepreg can be appropriately selected according to the purpose, and can be, for example, 50 μm to 500 μm. From the viewpoint of thermal conductivity and flexibility, it is preferably 60 μm to 300 μm.
Here, the average thickness of the prepreg is a value given as an arithmetic average value obtained by measuring the thicknesses of five points of the target prepreg using a micrometer or the like.

Specific examples of the material of the substrate include inorganic fibers such as E glass, D glass, S glass, and Q glass, organic fibers such as polyimide, polyester, and tetrafluoroethylene, and mixtures thereof. These base materials may have the shape of a woven fabric, a nonwoven fabric, a robink, a chopped strand mat, and a surfacing mat, for example. The material and shape of the substrate are selected depending on the intended use and performance of the molded product, and one or more materials and shapes can be combined as required.

The thickness of the substrate is not particularly limited, and can be, for example, 0.03 mm to 0.5 mm. The substrate is preferably surface-treated with a silane coupling agent or the like or mechanically subjected to fiber opening treatment from the viewpoint of heat resistance, moisture resistance, workability, etc. of the cured product.
The amount of the resin composition attached to the substrate is preferably 20% by mass to 90% by mass, more preferably 30% by mass to 90% by mass, and more preferably 40% by mass to 80% by mass as the ratio of the resin composition to the prepreg after drying. More preferred is mass%.
After impregnating the substrate with the resin composition so that the amount of the resin composition attached to the substrate is within the above range, the substrate is usually heated and dried at a temperature of 100 ° C. to 200 ° C. for 1 minute to 30 minutes, and semi-cured ( The prepreg of the third embodiment can be obtained.
There is no restriction | limiting in particular in the method of impregnating a resin composition to a base material, For example, the method of apply | coating with a coating machine can be mentioned. Specifically, for example, a vertical coating method in which the base material is pulled through the varnish of the resin composition, and the resin composition is coated on the support film, and then the support film coated with the resin composition is applied. A horizontal coating method in which a substrate is pressed and impregnated can be mentioned. From the viewpoint of suppressing the uneven distribution of the inorganic filler in the substrate, the horizontal coating method is suitable.

The solvent residual amount in the prepreg of the third embodiment is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and further preferably 0.7% by mass or less.

The amount of solvent remaining in the prepreg is determined from the change in mass before and after drying when the prepreg is cut into 40 mm squares and dried in a thermostat preheated to 190 ° C. for 2 hours.

The prepreg of the third embodiment may be used after the surface is flattened by hot pressing. As a method of hot pressurization, a method using a hot press, a hot roll, a laminator, or the like can be arbitrarily selected.
When hot pressing is performed by a method using a hot press, the heating temperature is preferably set as appropriate according to the type of carbodiimide compound used in the resin composition, the type of curing agent, and the like. In general, the heating temperature is preferably 60 ° C. to 180 ° C., more preferably 120 ° C. to 150 ° C. The degree of vacuum is preferably 3 Pa to 0.1 kPa. The pressing pressure is preferably 0.5 MPa to 4 MPa, more preferably 1 MPa to 2 MPa.

<Resin sheet>
The resin sheet of the present embodiment is obtained by molding the resin composition of the present embodiment into a sheet shape. As a resin sheet of this embodiment, it can manufacture by apply | coating the resin composition of this embodiment on a mold release base material, and drying, for example. At this time, after drying, if two surfaces of the resin sheet are smoothed by facing two sheets of the resin sheet of this embodiment facing each other or applying a release substrate to the resin sheet and hot pressing as necessary, It is preferable because pinholes and the like can be eliminated.

The release substrate is not particularly limited as long as it can withstand the temperature during drying, and is generally used as a polyethylene terephthalate film with a release agent, a polyimide film, a resin film such as an aramid film, and a release agent. A metal foil such as an attached aluminum foil can be used.

The average thickness of the resin sheet is not particularly limited and can be appropriately selected depending on the purpose. For example, the average thickness of the resin sheet is preferably 100 μm to 500 μm, and more preferably 100 μm to 300 μm. In addition, the average thickness of the resin sheet is obtained as an arithmetic average value by measuring the thickness of five points using a micrometer.

The resin sheet is obtained as follows, for example. First, each component which comprises the resin composition of this embodiment is mixed, melt | dissolved, disperse | distributed etc., and the varnish of the resin composition of this embodiment is prepared. And the prepared varnish is provided on a mold release base material. The application of the varnish can be performed by a known method. Specific examples of the varnish application method include a comma coating method, a die coating method, a lip coating method, and a gravure coating method. As an application method for forming a resin sheet with a predetermined thickness, a comma coating method for passing an object to be coated between gaps, a die coating method for applying a varnish with a flow rate adjusted from a nozzle, or the like can be applied.

The drying temperature is preferably set appropriately depending on the solvent used for the varnish, and is generally about 80 ° C. to 180 ° C. The drying time can be determined by considering the varnish gelation time and the thickness of the resin sheet, and is not particularly limited. After drying, the release substrate is removed to obtain a resin sheet.
The solvent residual amount in the resin sheet is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, from the viewpoint of concern about bubble formation during outgas generation during curing. More preferably, it is 0.7 mass% or less.

The residual amount of solvent in the resin sheet is determined from the change in mass before and after drying when the resin sheet is cut into a 40 mm square and dried in a thermostat preheated to 190 ° C. for 2 hours.

The resin sheet of the present embodiment may be used after the surface has been flattened before being laminated or pasted by hot pressing with a press, a roll laminator or the like. As a method of hot pressurization, a method using a hot press, a hot roll, a laminator, or the like can be arbitrarily selected.
When hot pressing is performed by a method using a hot press, the heating temperature is preferably appropriately set according to the type of carbodiimide compound used in the resin composition, the type of curing agent, and the like, and generally 60 ° C. to 180 ° C. The temperature is preferably 120 ° C. to 150 ° C. The degree of vacuum is preferably 3 Pa to 0.1 kPa. The pressing pressure is preferably 0.5 MPa to 4 MPa, more preferably 1 MPa to 2 MPa.

The resin sheet of this embodiment includes a first resin layer containing the resin composition of this embodiment and a second resin layer containing the resin composition of this embodiment laminated on the first resin layer. It is preferable. For example, the resin sheet of this embodiment is a laminate of a first resin layer formed from the resin composition of this embodiment and a second resin layer formed of the resin composition of this embodiment. It is preferable. Thereby, the withstand voltage can be further improved. The resin composition of this embodiment for forming the first resin layer and the second resin layer may have the same composition or different compositions. It is preferable that the resin composition of this embodiment which forms a 1st resin layer and a 2nd resin layer is the same composition.

This can be considered as follows, for example. That is, by overlapping two resin layers, a thinned portion (pinhole or void) that may exist in one resin layer is compensated by the other resin layer. Thereby, it can be considered that the minimum insulation thickness can be increased and the withstand voltage is further improved. The probability of occurrence of pinholes or voids in the resin sheet manufacturing method is not high, but by overlapping two resin layers, the probability of overlap of thin parts becomes the square, and the number of pinholes or voids approaches zero. become. Since dielectric breakdown occurs at a place where the insulation is weakest, it can be considered that the effect of further improving the withstand voltage can be obtained by overlapping two resin layers.

<Resin composition>
The resin composition of the present embodiment contains a carbodiimide compound having at least one carbodiimide group in one molecule, a curing agent, and an inorganic filler, and may contain other components as necessary.
The use of the resin composition of the present embodiment is not particularly limited, and can be suitably used, for example, as a thermosetting resin composition for producing a laminated board or the like.

Due to recent demands for higher density and reliability of wiring, the laminated board material requires high copper foil adhesion and heat resistance, and low thermal expansion coefficient (low thermal expansion). For example, for the formation of fine wiring, the adhesiveness of a metal foil such as a copper foil to a laminated board is preferably 0.7 kN / m or more as a copper foil peeling strength, and 0.9 kN / m or more It is more preferable that In addition, it is necessary to make the laminate more multilayered by using a build-up material or the like in order to increase the wiring density, and high reflow heat resistance is required. The heat resistance with copper, which is a guideline for reflow heat resistance evaluation, is preferably free from blistering for 30 minutes or more. Furthermore, as the wiring density is increased, the laminate is in the direction of being made thinner, and the warp of the laminate during heat treatment is required to be small. In order to reduce the warp of the laminate, it is effective that the laminate is highly elastic. When the flexural modulus of the laminate is used as an index, the flexural modulus is preferably 30 GPa or more, and 32 GPa or more. It is more preferable that Further, in order to reduce warpage, it is effective that the laminate has a low thermal expansion property. Particularly, it is effective that the thermal expansion coefficient in the plane direction is low, and the linear thermal expansion coefficient in the plane direction is 7 ppm / ° C. Or less, more preferably 5 ppm / ° C. or less. In order to reduce warpage, it is also effective that the laminate has low cure shrinkage, and in particular, it is effective that the cure shrinkage rate in the plane direction is small, and the cure shrinkage rate in the plane direction is 0.5. % Or less is preferable, and 0.3% or less is more preferable. In addition, as the wiring density increases, the laminated board is in a direction that requires more reliability, and the inner wall roughness of the drill hole during drilling is required to be small. The evaluation of the inner wall roughness of the drill hole is evaluated by the penetration of plated copper into the inner wall of the drill hole, and the maximum plating penetration length is preferably 20 μm or less, and more preferably 15 μm or less. Furthermore, the demand for high-speed response continues to increase, and it is preferable that the relative dielectric constant of the laminate is 4.3 or less and the dielectric loss tangent is 0.007 or less.
Under such circumstances, the present inventors have invented the resin composition of this embodiment containing a carbodiimide compound as a result of intensive studies.
Hereinafter, each component contained in the resin composition of this embodiment is explained in full detail.

(Carbodiimide compound)
The carbodiimide compound used in the present embodiment is not particularly limited as long as it is a carbodiimide compound having at least one carbodiimide group in one molecule. The carbodiimide compound used in the present embodiment is preferably a carbodiimide compound having at least two carbodiimide groups in one molecule from the viewpoint of obtaining a strong cured product.
The carbodiimide compound used in the present embodiment may be an aromatic carbodiimide compound or an aliphatic carbodiimide compound, and is preferably an aromatic carbodiimide compound from the viewpoint of high reactivity with a curing agent. .
In the present embodiment, the aromatic carbodiimide compound refers to a carbodiimide compound in which a nitrogen atom of a carbodiimide group is bonded to a carbon atom constituting an aromatic ring such as a benzene ring. On the other hand, the aliphatic carbodiimide compound in the present embodiment refers to a carbodiimide compound in which a nitrogen atom of a carbodiimide group is bonded to a carbon atom constituting an alkylene group.

The carbodiimide compound used in the present embodiment is preferably obtained by using a compound (a) having two isocyanate groups in one molecule as a production raw material. As the compound (a) having two isocyanate groups in one molecule, an isocyanate compound represented by at least one selected from the group consisting of the following general formula (II) and the following general formula (III) is preferable.

In the general formula (II), R ₂ is a single bond, a divalent saturated hydrocarbon group having 1 to 5 carbon atoms or an oxygen atom, and R _2a and R _2b are each independently a monovalent having 1 to 5 carbon atoms. A saturated hydrocarbon group or a halogen atom, and s and t are each independently an integer of 0 to 4;

In the general formula (III), each R ₃ is independently a monovalent saturated hydrocarbon group having 1 to 5 carbon atoms, and y is an integer of 0 to 4.

In the general formula (II), the divalent saturated hydrocarbon group having 1 to 5 carbon atoms represented by R ₂ may be linear, branched or cyclic. Also good.
Examples of the divalent saturated hydrocarbon group represented by R ₂ include a methylene group, an ethylene group, a propylene group, a butylene group, an isobutylene group, a pentylene group, a cyclopropylene group, a cyclobutylene group, and a cyclopentylene group. .
R ₂ is preferably a single bond, a methylene group, or an isobutylene group from the viewpoint of low thermal expansion of the cured product, more preferably a single bond or a methylene group, and still more preferably a methylene group from the viewpoint of the heat resistance of the cured product. .
Examples of the monovalent saturated hydrocarbon group represented by R _2a and R _2b include methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, cyclopropyl group, cyclobutyl group, A cyclopentyl group etc. are mentioned.
Examples of the halogen atom represented by R _2a and R _2b include a fluorine atom, a chlorine atom, and a bromine atom.
The R _2a and R _2b, from the viewpoint of chemical resistance of the cured product, a fluorine atom or a methyl group is preferable. s and t are each independently preferably 0 or 1. When s is 1, R _2a is preferably a methyl group or a fluorine atom from the viewpoint of resin compatibility. When t is 1, R _2b is preferably a methyl group or a fluorine atom from the viewpoint of resin compatibility.

In the general formula (III), the monovalent saturated hydrocarbon group having 1 to 5 carbon atoms represented by R ₃ may be linear, branched or cyclic. Also good.
Examples of the monovalent saturated hydrocarbon group represented by R ₃ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, and isopentyl group. Etc.
R ₃ is preferably a methyl group from the viewpoint of yield during synthesis.
In the general formula (III) from the viewpoint of chemical resistance of the cured product, y is preferably 0 or 1, and when y is 1, R ₃ is preferably a methyl group.

Specific examples of the isocyanate compounds represented by the general formula (II) and the general formula (III) include diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, diphenylether-4,4′-diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3,5-triisopropyl-2,6-diisocyanate benzene, p-benzene And diisocyanate compounds such as diisocyanate.
The compound (a) having two isocyanate groups in one molecule can be used alone or in combination of two or more.

Among these, unreacted isocyanate groups hardly remain and the cured product is excellent in heat resistance. Diisocyanate and the like are preferable, and diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate and the like, which are excellent in low curing shrinkage of the cured product, are more preferable.

As a raw material for producing the carbodiimide compound used in the present embodiment, a polymethylene polyphenyl polyisocyanate having a high polynuclear body, which is a compound represented by the following general formula (IV), may be used as necessary. Furthermore, if necessary, an isocyanate compound in which a part of the isocyanate group is modified with various polyhydric alcohol compounds, phenol compounds, ε-caprolactam or the like may be used in combination.

In general formula (IV), r is a positive number. The weight average molecular weight of the compound represented by the general formula (IV) is preferably 500 to 10,000, and more preferably 1,000 to 5,000.
In the present embodiment, the weight average molecular weight is a value measured by the following method.
A measurement object is dissolved in tetrahydrofuran (for liquid chromatograph), and a PTFE (polytetrafluoroethylene) filter (manufactured by Kurashiki Boseki Co., Ltd., for HPLC (high performance liquid chromatography) pretreatment, chromatodisc, model number: 13N, pore size: 0.45 μm] to remove insoluble matter. GPC (pump: L6200 Pump (manufactured by Hitachi, Ltd.), detector: differential refractive index detector L3300 RI Monitor (manufactured by Hitachi, Ltd.), column: TSKgel-G5000HXL and TSKgel-G2000HXL (both in total) (Made by Co., Ltd.) in series, column temperature: 30 ° C., eluent: tetrahydrofuran, flow rate: 1.0 ml / min, standard substance: polystyrene], and the weight average molecular weight is measured.

Further, the carbodiimide compound used in the present embodiment is preferably obtained using the aromatic monoisocyanate compound (b) as a production raw material. The aromatic monoisocyanate compound (b) is preferably an isocyanate compound represented by the following general formula (V).

In the general formula (V), each R ₁ independently represents a halogen atom, a monovalent saturated hydrocarbon group having 1 to 5 carbon atoms, or a trifluoromethyl group, and x is an integer of 0 to 5.

In the general formula (V), the monovalent saturated hydrocarbon group having 1 to 5 carbon atoms represented by R ₁ may be linear, branched or cyclic. Also good.
Examples of the monovalent saturated hydrocarbon group represented by R ₁ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and an isopentyl group. Etc.
Examples of the halogen atom represented by R ₁ include a fluorine atom, a chlorine atom, and a bromine atom.
In the general formula (V), x is preferably an integer of 0 to 3, more preferably 0 from the viewpoint of the yield during synthesis.

Specific examples of the isocyanate compound represented by the general formula (V) include phenyl isocyanate, 2,6-dimethylphenyl isocyanate, 3,5-dimethylphenyl isocyanate, 2,6-diisopropylphenyl isocyanate, 4-fluorophenyl isocyanate. 2,4-difluorophenyl isocyanate, 2,4,6-trifluorophenyl isocyanate, 3- (trifluoromethyl) phenyl isocyanate, 4- (trifluoromethyl) phenyl isocyanate and other monoisocyanate compounds.
An aromatic monoisocyanate compound (b) can be used individually by 1 type or in combination of 2 or more types.
Among these, phenyl isocyanate, 2,6-dimethylphenyl isocyanate, and 3,5-dimethylphenyl isocyanate are preferable because the molecular weight and viscosity of the synthesized carbodiimide compound can be easily adjusted and are commercially inexpensive. These are commercially available from Tosoh Corporation, BASF INOAC Polyurethane Corporation, Chuo Kasei Co., Ltd., Junsei Chemical Co., Ltd., Wako Pure Chemical Industries, Ltd.

The carbodiimide compound used in the present embodiment is composed of a compound (a) component having two isocyanate groups in one molecule, an aromatic monoisocyanate compound (b) component, and other components as necessary as a synthetic raw material. It may be obtained by use and carbodiimidization reaction.
The amount of component (a) and component (b) used is the number of isocyanate groups in component (a) (amount of component (a) / isocyanate group equivalent of component (a)) and the number of isocyanate groups in component (b). The ratio of ((b) component usage / (b) component isocyanate group equivalent) ((a) component isocyanate group number / (b) component isocyanate group number) is 0.4 to 20.0. Is more preferable, 1.0 to 20.0 is more preferable, and 2.0 to 20.0 is still more preferable.
If the ratio of the number of isocyanate groups in component (a) to the number of isocyanate groups in component (b) (number of isocyanate groups in component (a) / number of isocyanate groups in component (b)) is 0.4 or more, the heat resistance of the cured product and Chemical resistance tends to improve. If the ratio (number of isocyanate groups in component (a) / number of isocyanate groups in component (b)) is 20.0 or less, gelation tends not to occur during the synthesis of the carbodiimide compound.

Further, an organic solvent may be used for this carbodiimidization reaction. The amount of the organic solvent used is preferably 0 to 1000 parts by mass per 100 parts by mass of the sum of the component (a), the component (b) and other components used as necessary. Part to 500 parts by mass is more preferable, and 0 part to 400 parts by mass is even more preferable. If component (a), component (b), other components used as needed, and the carbodiimide compound synthesized by carbodiimidization reaction are low-viscosity liquid substances, synthesis is performed without using an organic solvent. May be. On the other hand, if these components are solid or a highly viscous viscous material, it is preferable to use an appropriate amount of an organic solvent. However, if the amount of the organic solvent used is too large, synthesis may take a long time and production costs may increase.

Examples of organic solvents used in the carbodiimidization reaction include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ether solvents such as tetrahydrofuran, aromatic solvents such as toluene, xylene, and mesitylene, and hydrocarbon solvents. Petroleum solvents, N atom-containing solvents such as dimethylformamide and dimethylacetamide, S atom-containing solvents such as dimethyl sulfoxide, and ester solvents such as γ-butyrolactone.
These organic solvents can be used individually by 1 type or in combination of 2 or more types. Among these, from the viewpoint of being highly soluble and volatile and hardly remaining as a residual solvent during the production of the prepreg, and from the viewpoint of moisture resistance and heat resistance of the cured product, copper foil adhesion and low dielectric constant, toluene, xylene, Aromatic solvents such as mesitylene and ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone are preferred.

In the carbodiimidization reaction, a reaction catalyst for carbodiimidization can be arbitrarily used as necessary, and the type of the reaction catalyst is not particularly limited. Examples of reaction catalysts include organophosphorus compounds such as 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3 -Methyl-1-phenyl-2-phospholene-2-oxide and the like. Of these, 3-methyl-1-phenyl-2-phospholene-2-oxide is particularly preferable because it has high reactivity and can provide a high yield.
Here, the amount of the reaction catalyst used is based on the total number of isocyanate groups of the component (a), the number of isocyanate groups of the component (b), and the number of isocyanate groups of other components used as necessary. Therefore, 0.05 mol% to 2.0 mol% is preferable. When the amount of the reaction catalyst used is 0.05 mol% or more, the carbodiimidization reaction does not take a long time, and a desired reaction rate tends to be realized. Moreover, if the usage-amount of a reaction catalyst is 2.0 mol% or less, the reaction rate of carbodiimidization reaction does not become too quick, and it exists in the tendency for end point management of reaction to become easy.

A carbodiimide compound is produced by charging the above-mentioned synthesis raw materials and, if necessary, an organic solvent and a reaction catalyst in a synthesis kettle, stirring for 0.1 to 10 hours while heating and keeping heat as necessary, and causing a carbodiimidization reaction with decarboxylation. Is done. The synthesis temperature is preferably 5 ° C to 180 ° C. When the synthesis temperature is 5 ° C. or higher, the reaction rate of the carbodiimidization reaction does not become too slow, and the reaction tends to be completed in an acceptable time. Moreover, if the synthesis temperature is 180 ° C. or lower, the possibility of causing a side reaction tends to be reduced.

Further, the end point of the carbodiimidization reaction and the confirmation that the carbodiimide compound has been formed can be obtained by taking a small amount of sample after the reaction for a predetermined time and performing FT-IR (Fourier transform infrared spectroscopy) measurement.
When performing end point check of carbodiimidization reaction by FT-IR measurement, a synthetic raw material component (a), (b) the peak of the component such as 2260 ± 5 cm due to the isocyanate groups contained in the isocyanate compound ^-1 disappeared Further, the appearance of a peak at 2120 ± 5 cm ⁻¹ due to the generated carbodiimide group is confirmed. In this way, a carbodiimide compound is obtained.

The carbodiimide compound used in the present embodiment preferably includes a carbodiimide compound represented by the following general formula (I) (hereinafter sometimes referred to as “specific carbodiimide compound”).

In general formula (I), Ar ₁ is at least one selected from the group consisting of groups represented by the following general formula based on the following general formula represented by (IIA) (IIIA), R 1 each independently A halogen atom, a monovalent saturated hydrocarbon group having 1 to 5 carbon atoms, or a trifluoromethyl group, m is 0 or a positive number, and x is independently an integer of 0 to 5;

In the general formula (IIA), R ₂ is a single bond, a divalent saturated hydrocarbon group having 1 to 5 carbon atoms or an oxygen atom, and R _2a and R _2b are each independently a monovalent having 1 to 5 carbon atoms. A saturated hydrocarbon group or a halogen atom, and s and t are each independently an integer of 0 to 4, and specific examples thereof are the same as R ₂ , R _2a , R _2b , s and t in the general formula (II) It is. Moreover, * in general formula (IIA) shows the position couple | bonded with an adjacent nitrogen atom in general formula (I).

In general formula (IIIA), each R ₃ is independently a monovalent saturated hydrocarbon group having 1 to 5 carbon atoms, y is an integer of 0 to 4, and specific examples thereof are those of general formula (III). Same as R ₃ and y. Moreover, * in general formula (IIIA) shows the position couple | bonded with an adjacent nitrogen atom in general formula (I).

The production process of the specific carbodiimide compound is not particularly limited, and the compound (a) component having two isocyanate groups in one molecule and the aromatic monoisocyanate compound (b) component are used as a raw material for synthesis. However, it may be obtained by a carbodiimidization reaction, but is not limited thereto.

The weight average molecular weight of the specific carbodiimide compound is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and still more preferably 1,000 to 20,000.

The proportion of the carbodiimide compound in the solid content of the resin composition of the present embodiment is preferably 5% by mass to 70% by mass, more preferably 5% by mass to 60% by mass, and more preferably 5% by mass to More preferably, it is 55 mass%.
In addition, in this embodiment, solid content means the non-volatile component of the components which comprise a resin composition.
The proportion of the specific carbodiimide compound in the carbodiimide compound contained in the resin composition of the present embodiment is preferably 10% by mass to 100% by mass, more preferably 20% by mass to 100% by mass, More preferably, it is 30% by mass to 100% by mass.

(Curing agent)
The resin composition of this embodiment contains a curing agent. The curing agent used in the present embodiment is not particularly limited as long as it is a compound having a functional group capable of undergoing a curing reaction with a carbodiimide compound.
The curing agent used in the present embodiment preferably includes at least one selected from the group consisting of carboxylic acid, epoxy compound, phenol compound and amine. Among these, it is preferable to use an epoxy compound as a curing agent from the viewpoint of moisture resistance of the cured product.

When carboxylic acid is used as the curing agent, specific examples of carboxylic acid include known dicarboxylic acid compounds such as maleic acid, phthalic acid, and succinic acid, trimellitic anhydride, and the like. Carboxylic acid can be used individually by 1 type or in combination of 2 or more types.

When a phenol compound is used as the curing agent, specific examples of the phenol compound include known phenol compounds such as phenol novolac. A phenol compound can be used individually by 1 type or in combination of 2 or more types.

When an amine is used as the curing agent, specific examples of the amine include, for example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, m-xylenediamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, diethylaminopropylamine, Isophoronediamine, 1,3-bisaminomethylcyclohexane, bis (4-aminocyclohexyl) methane, norbornenediamine, 1,2-diaminocyclohexane, laromine, diaminodiphenylmethane, metaphenylenediamine, diaminodiphenylsulfone, polyoxypropylenediamine, poly Mention may be made of oxypropylene triamine, polycyclohexyl polyamine mixtures and N-aminoethylpiperazine. An amine can be used individually by 1 type or in combination of 2 or more types.

When an epoxy compound is used as the curing agent, the epoxy compound is preferably a compound having at least two epoxy groups in one molecule.
Compounds having at least two epoxy groups in one molecule include bisphenol A, bisphenol F, biphenyl, novolac, dicyclopentadiene, polyfunctional phenol, naphthalene, aralkyl modified, alicyclic Examples thereof include glycidyl ethers such as glycidyl ethers, glycidyl amines, and glycidyl esters, which can be used singly or in combination of two or more.

As an epoxy compound, the cured product has high rigidity, dielectric properties, heat resistance, flame resistance, moisture resistance and low thermal expansion, and is solid at room temperature (20 ° C to 23 ° C). A naphthalene ring-containing epoxy resin, a biphenyl group-containing epoxy resin, and a dicyclopentadiene-type epoxy resin are preferable from the viewpoint that tackiness is reduced and handling becomes easy.
Moreover, as an epoxy compound, a naphthalene type epoxy resin, a biphenyl type epoxy resin, a naphthol aralkyl / cresol copolymer type epoxy resin, and a biphenyl aralkyl type epoxy resin are preferable from the viewpoint of solubility in an aromatic organic solvent.
In recent years, there has been an increase in the number of multilayered boards using a build-up material or the like for the purpose of increasing the number of layers and increasing the density of wiring. From the viewpoint of moldability, naphthol is an epoxy compound. Aralkyl / cresol copolymer epoxy resins and biphenyl aralkyl epoxy resins are preferred.

When a naphthol aralkyl / cresol copolymer type epoxy resin is used as the epoxy compound, the naphthol aralkyl / cresol copolymer type epoxy resin is preferably a compound containing two structural units represented by the following general formula (VI).

In general formula (VI), m and n are positive numbers which may be different from each other.
The ratio of the two structural units represented by the general formula (VI) is not particularly limited.
The weight average molecular weight of the compound represented by the general formula (VI) is preferably 500 to 10,000, more preferably 500 to 8,000, and still more preferably 500 to 6,000.
As the naphthol aralkyl / cresol copolymer epoxy resin, NC-7000L manufactured by Nippon Kayaku Co., Ltd. is available.

When a biphenyl aralkyl type epoxy resin is used as the epoxy resin, a compound containing two structural units represented by the following general formula (VII) is preferable.

In general formula (VII), p and q are positive numbers which may be different from each other.
The ratio of the two structural units represented by the general formula (VII) is not particularly limited.
The weight average molecular weight of the compound represented by the general formula (VII) is preferably 500 to 10,000, more preferably 500 to 8,000, and still more preferably 500 to 6,000.
As the biphenyl aralkyl type epoxy resin, NC-3000H manufactured by Nippon Kayaku Co., Ltd. is available.

When an epoxy compound is used as the curing agent, the content of the carbodiimide compound per 100 parts by mass of the total of the carbodiimide compound and the epoxy compound is in the range of 10 parts by mass to 90 parts by mass, and the content of the epoxy compound is 90 parts by mass to It is preferably in the range of 10 parts by mass, the carbodiimide compound content is preferably in the range of 30 parts by mass to 90 parts by mass, and the epoxy compound content is more preferably in the range of 70 parts by mass to 10 parts by mass. More preferably, the carbodiimide compound content is in the range of 30 to 80 parts by mass, and the epoxy compound content is in the range of 70 to 20 parts by mass. If the content of the carbodiimide compound per 100 parts by mass of the total of the carbodiimide compound and the epoxy compound is 10 parts by mass or more, the elastic modulus of the cured product, low thermal expansion, moisture and heat resistance, dielectric properties, adhesion, flame retardancy Etc. tend to improve. If the content of the carbodiimide compound per 100 parts by mass of the carbodiimide compound and the epoxy compound is 90 parts by mass or less, the moldability of the resin composition tends to be improved, and the plating solution resistance of the cured product, etc. The chemical resistance tends to be improved.

When carboxylic acid is used as the curing agent, the content of carboxylic acid in the resin composition is preferably 100% by mass or less, more preferably 50% by mass or less, relative to the carbodiimide compound contained, More preferably, it is 30 mass% or less.

When a phenol compound is used as the curing agent, the content of the phenol compound in the resin composition is preferably 100% by mass or less, more preferably 50% by mass or less, with respect to the carbodiimide compound contained, More preferably, it is 30 mass% or less.

When an amine is used as the curing agent, the content of the amine compound in the resin composition is preferably 100% by mass or less, more preferably 50% by mass or less, based on the carbodiimide compound contained. More preferably, it is at most mass%.

(Inorganic filler)
The resin composition of this embodiment contains an inorganic filler. The inorganic filler used in this embodiment is not particularly limited, silica such as fused silica, deflagration silica and crushed silica, glass short fibers, glass fine powder, glass such as hollow glass, mica, talc, calcium carbonate, Examples thereof include quartz and metal hydrate. An inorganic filler can be used individually by 1 type or in combination of 2 or more types.
Among these, silica is preferable from the viewpoint of low thermal expansion property and low dielectric loss tangent of the cured product, low thermal expansion property of the cured product, copper foil adhesiveness, heat resistance, moisture resistance, flame resistance, low dielectric loss tangent, etc. In view of the above, spherical silica such as fused silica and deflagration silica is more preferable.
The inorganic filler preferably has an average particle size of 5.0 μm or less, more preferably 0.3 μm to 5.0 μm, still more preferably 0.3 μm to 2.0 μm, and more preferably 0.5 μm to Those having a thickness of 1.0 μm are particularly preferable.

When silica is used as the inorganic filler, the silica preferably has an average particle size of 5.0 μm or less, more preferably 0.3 μm to 5.0 μm, and more preferably 0.3 μm to 2.0 μm. More preferably, the thickness is 0.5 μm to 1.0 μm.
When spherical silica is used as the inorganic filler, the one having an average particle size of 5.0 μm or less is the thermal expansion property of the cured product, copper foil adhesiveness, heat resistance, moisture resistance, flame resistance, low dielectric loss tangent From the viewpoint of the above, it is preferable that the thickness is 0.3 μm to 5.0 μm, more preferable is 0.3 μm to 2.0 μm, and particularly preferable is 0.5 μm to 1.0 μm.

In the present embodiment, the average particle diameter is a particle diameter (volume average) in which the integrated distribution is 50% in the integrated distribution expressed by the accumulation of the frequencies, where the particle diameter is a class and the volume is a frequency using the following method. Particle size). As a method for measuring the particle size of the inorganic filler, for example, using a device such as laser diffraction, dynamic light scattering, and small angle X-ray scattering, a method of simultaneously measuring a large number of particles, an electron microscope, an atomic force microscope, etc. And a method of measuring the particle size of each particle. Using a method such as liquid phase centrifugation, field flow fractionation, particle size exclusion chromatography, fluid dynamics chromatography, or the like, a pretreatment for separating particles of 100 μm or more may be performed before measuring the particle size. Moreover, when a measurement sample is the hardened | cured material of a resin composition, the ash obtained as a residue after processing at high temperature of 800 degreeC or more with a muffle furnace etc. can be measured by said method.

In the present embodiment, when silica is used as the inorganic filler, other fillers may be used in combination with silica (preferably spherical silica). As other fillers, metal hydrates such as aluminum hydroxide and magnesium hydroxide are preferable from the viewpoint of low thermal expansion, elastic modulus, heat resistance, flame retardancy, etc. of the cured product, and among the metal hydrates, From the viewpoint of achieving both high heat resistance and flame retardancy of the cured product, metal hydrates having a thermal decomposition temperature of 300 ° C. or higher are more preferable, boehmite type aluminum hydroxide (AlOOH), gibbsite type aluminum hydroxide (Al (OH ₃ ) A boehmite type hydroxide which has a thermal decomposition temperature adjusted to 300 ° C. or higher by heat treatment, magnesium hydroxide, etc., is more preferable, is inexpensive, has a thermal decomposition temperature of 350 ° C. or higher, and has high chemical resistance. Aluminum (AlOOH) is particularly preferred.
In this embodiment, even when silica is not used as the inorganic filler, other fillers may be used as the inorganic filler.

When other fillers are used together with silica (preferably spherical silica) as the inorganic filler, the content ratio (silica / other filler) based on mass between silica and other fillers may be 2.0 or more. Preferably, it is 2.5 or more, more preferably 3.0 or more.

The inorganic filler used in the present embodiment may be surface-treated with a silane coupling agent.
A commercially available silane coupling agent can be used. In consideration of compatibility with the carbodiimide compound, it is preferable to use a silane coupling agent having an epoxy group, amino group, mercapto group, ureido group or hydroxyl group at the terminal.
Specific examples of the silane coupling agent include, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropylmethyl. Dimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3- Examples include mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane. These silane coupling agents can be used alone or in combination of two or more.
Among these, 3-glycidoxypropyltrimethoxysilane is preferable from the viewpoints of the copper foil adhesiveness and heat resistance of the cured product.
The treatment method of the inorganic filler with the silane coupling agent is not particularly limited, and may be a wet treatment or a dry treatment, and is preferably a wet treatment.
Silica can also be obtained commercially from Admatechs Corporation. For example, as a spherical silica (fused spherical silica) having an average particle size of 0.5 μm or less that has been surface-treated (wet-treated) with 3-glycidoxypropyltrimethoxysilane, the trade name SC-2050MTE manufactured by Admatechs Co., Ltd. Etc.

As content of the inorganic filler in the resin composition of this embodiment, it is 10 mass with respect to 100 mass parts of the total mass of the carbodiimide compound, the hardening | curing agent (preferably epoxy compound), and the below-mentioned maleimide compound used as needed. Part to 300 parts by weight, preferably 100 parts to 250 parts by weight, and more preferably 150 parts to 250 parts by weight. If content of an inorganic filler is 10 mass parts or more, it exists in the tendency for the elasticity modulus of cured | curing material, low thermal expansibility, moisture heat resistance, and low dielectric loss tangent to improve. Moreover, if content of an inorganic filler is 300 mass parts or less, it exists in the tendency for chemical resistance, such as the moldability of a resin composition and the plating solution resistance of hardened | cured material, to improve.

When silica is used as the inorganic filler in the resin composition of the present embodiment, the content of silica (preferably spherical silica) is a carbodiimide compound, a curing agent (preferably an epoxy compound), and a maleimide described later used as necessary. It is preferably 10 to 300 parts by mass, more preferably 100 to 250 parts by mass, and more preferably 150 to 250 parts by mass with respect to 100 parts by mass of the total mass with the compound. Further preferred.
When the silica content is 10 parts by mass or more, the elastic modulus, low thermal expansion, moisture and heat resistance, and low dielectric loss tangent of the cured product tend to be improved. Moreover, if content of a silica is 300 mass parts or less, it exists in the tendency for chemical resistance, such as the moldability of a resin composition and the plating solution resistance of hardened | cured material, to improve.

The content of other fillers should be 0 to 200 parts by mass with respect to 100 parts by mass of the total mass of a carbodiimide compound, a curing agent (preferably an epoxy compound), and a maleimide compound described later if necessary. It is preferably 0 to 150 parts by mass. By setting the content of other fillers to 200 parts by mass or less, chemical resistance such as moldability of the resin composition and plating solution resistance of the cured product tends to be improved.

In the present embodiment, when silica is used as the inorganic filler, the content of silica (preferably spherical silica) and other fillers is a carbodiimide compound, a curing agent (preferably an epoxy compound), and a maleimide described later used as necessary. Silica is preferably 10 to 300 parts by mass, other fillers are preferably 0 to 200 parts by mass, and silica is 100 to 250 parts by mass with respect to 100 parts by mass of the total mass of the compound. More preferably, the other filler is 0 to 150 parts by mass, the silica is 150 to 250 parts by mass, and the other filler is more preferably 0 to 150 parts by mass.

(Maleimide compound)
The resin composition of the present embodiment may contain a maleimide compound from the viewpoint of the low thermal expansion property, low curing shrinkage property, heat resistance, moisture resistance, low dielectric loss tangent, etc. of the cured product. The maleimide compound used in the present embodiment is not particularly limited, and a maleimide compound having at least two maleimide groups in one molecule is preferable.

Examples of maleimide compounds having at least two maleimide groups in one molecule include bis (4-maleimidophenyl) methane, polyphenylmethanemaleimide, bis (4-maleimidophenyl) ether, bis (4-maleimidophenyl) sulfone, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, m-phenylene bismaleimide and 2,2-bis (4- ( 4-maleimidophenoxy) phenyl) propane. Among these, bis (4-maleimidophenyl) methane, polyphenylmethanemaleimide, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide from the viewpoint of solubility in solvents And 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane are preferred, and 2,2-bis (4- ( 4-maleimidophenoxy) phenyl) propane and polyphenylmethanemaleimide, bis (4-maleimidophenyl) methane are more preferred.

In the resin composition of the present embodiment, the amount of the carbodiimide compound used per 100 parts by mass of the total of the carbodiimide compound, the curing agent (preferably an epoxy compound) and the maleimide compound is in the range of 10 to 90 parts by mass, and the curing agent When the amount of (preferably epoxy compound) used is in the range of 90 to 10 parts by weight, the amount of maleimide compound used is preferably in the range of 0 to 70 parts by weight, and 0 to 60 parts by weight. The range is more preferably in the range of parts by mass, and still more preferably in the range of 0 to 50 parts by mass. If the amount of the maleimide compound used is 70 parts by mass or less, the moldability of the resin composition tends to be improved, and further, the chemical resistance such as the plating solution resistance of the cured product tends to be improved.

(solvent)
When handling the resin composition of this embodiment as a varnish, the resin composition of this embodiment may contain a solvent.
The solvent used in the present embodiment is not particularly limited. Solvents that can be used in this embodiment include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ether solvents such as tetrahydrofuran, aromatic solvents such as toluene, xylene, and mesitylene, and hydrocarbon solvents. Petroleum solvents, N atom-containing solvents such as dimethylformamide and dimethylacetamide, S atom-containing solvents such as dimethyl sulfoxide, and ester solvents such as γ-butyrolactone.
These solvents can be used alone or in combination of two or more.
When the resin composition of the present embodiment contains a solvent, the content of the solvent in the resin composition is preferably 10% by mass to 90% by mass, and more preferably 20% by mass to 80% by mass. Preferably, the content is 30% by mass to 70% by mass.

(Curing accelerator)
The resin composition of this embodiment may contain a curing accelerator. When an appropriate curing accelerator is used in combination, the molding temperature is 200 ° C. or lower, and there is a tendency that low temperature curability can be imparted to the resin composition of the present embodiment. In addition, flame retardancy and copper foil adhesion tend to be further improved.

Examples of curing accelerators include, for example, imidazole compounds and derivatives thereof, tertiary amine compounds, and quaternary ammonium salts. Among them, imidazole compounds and derivatives thereof are preferable from the viewpoints of heat resistance, flame retardancy, copper foil adhesion, and the like of cured products, and are the following reaction products of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole. The compound shown in (VIII) is more preferable because it is excellent in curing moldability at a relatively low temperature at 200 ° C. or lower, and the aging stability of the varnish and prepreg of the resin composition, and is also commercially inexpensive. .

The compound represented by the formula (VIII) is commercially available from Daiichi Kogyo Seiyaku Co., Ltd.

The content of the curing accelerator is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the total mass of the carbodiimide compound, the curing agent (preferably an epoxy compound) and the maleimide compound used as necessary. The content is more preferably 0 to 10 parts by mass, and still more preferably 0 to 5 parts by mass. By making content of a hardening accelerator into 20 mass parts or less, it is suppressed that the gel time of the varnish of the resin composition of this embodiment becomes short too much, and there exists a tendency for the moldability of a resin composition to improve. .

(Flame retardants)
The resin composition of this embodiment may contain a flame retardant. Examples of the flame retardant used in the present embodiment include triphenyl phosphate, tricresyl phosphate, trisdichloropropyl phosphate, phosphoric ester compounds, phosphazenes, phosphorous flame retardants such as red phosphorus, antimony trioxide, zinc molybdate, and the like. And inorganic flame retardant aids. In addition, it is preferable not to use the halogen-containing flame retardant containing bromine, chlorine, etc. as much as possible because it may cause environmental problems. A flame retardant can be used individually by 1 type or in combination of 2 or more types.
As a flame retardant, an inorganic flame retardant in which zinc molybdate is supported on an inorganic filler such as talc is a preferable flame retardant because it improves not only the flame retardancy but also the drill workability of the cured product.

The content of the flame retardant is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the total mass of the carbodiimide compound, the curing agent (preferably an epoxy compound) and the maleimide compound used as necessary. The content is more preferably 0 to 10 parts by mass, and still more preferably 0 to 5 parts by mass. If content of a flame retardant is 20 mass parts or less, the gel time of the varnish of the resin composition of this embodiment will not become too short, and it exists in the tendency for the moldability of a resin composition to improve.

(Other ingredients)
The resin composition of this embodiment may contain other components as necessary. Examples of other components include thermoplastic resins, elastomers, and organic fillers.
Examples of thermoplastic resins include, for example, tetrafluoroethylene resin, polyethylene resin, polypropylene resin, polystyrene resin, polyphenylene ether resin, phenoxy resin, polycarbonate resin, polyester resin, polyamide resin, polyimide resin, xylene resin, petroleum resin and silicone. Resin.
Examples of elastomers include, for example, polybutadiene, polyacrylonitrile, epoxy-modified polybutadiene, maleic anhydride-modified polybutadiene, phenol-modified polybutadiene, and carboxy-modified polyacrylonitrile.
Examples of the organic filler include organic particles such as silicone powder, polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, and polyphenylene ether.

The resin composition of this embodiment may contain an ultraviolet absorber, an antioxidant, a photopolymerization initiator, a fluorescent brightener, an adhesion improver, and the like as other components.
Examples of these materials include UV absorbers such as benzotriazoles, antioxidants such as hindered phenols and styrenated phenols, photopolymerization initiators such as benzophenones, benzyl ketals, and thioxanthones, and stilbene derivatives. Examples thereof include fluorescent brighteners, urea compounds such as urea silane, and adhesion improvers such as silane coupling agents.

<Method for producing resin composition>
The resin composition of the present embodiment may be prepared by any technique as long as the above various components can be dispersed and mixed. As a general technique, the resin composition of the present embodiment can be obtained by weighing the components, mixing and kneading using a roughing machine, a mixing roll, a planetary mixer, etc., and defoaming as necessary. Yes, but not limited to this.

<Laminated plate>
The laminate of this embodiment is a laminate of the prepreg of this embodiment.
The laminated plate of the present embodiment can be produced by, for example, stacking 1 to 20 prepregs of the present embodiment and forming a metal foil on one or both sides thereof.
The metal foil is not particularly limited as long as it is used for electrical insulating material applications. Specific examples of the metal foil include gold foil, copper foil, aluminum foil and the like, and copper foil is generally used. The average thickness of the metal foil is not particularly limited as long as it is 1 μm to 400 μm, for example, and a suitable thickness can be selected according to the electric power used. As the metal foil, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as intermediate layers, and copper layers with an average thickness of 0.5 μm to 15 μm are averaged on both surfaces. It is also possible to use a composite foil having a three-layer structure in which a copper layer having a thickness of 10 μm to 150 μm is provided, or a composite foil having a two-layer structure in which an aluminum foil and a copper foil are combined.

As for the molding conditions of the laminate, for example, the method of laminates for electrical insulation materials and multilayer plates can be applied, and multistage press, multistage vacuum press, continuous molding, autoclave molding, etc. are used, the temperature is 100 ° C. to 250 ° C., pressure 2 kg / cm ² to 100 kg / cm ² , and the heating time can be in the range of 0.1 hours to 5 hours. Moreover, a multilayer board can also be manufactured combining the prepreg of this embodiment, and the wiring board for inner layers.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples do not limit the present invention in any way.

-Production Example 1: Production of carbodiimide compound (A-1)-
Diphenylmethane-4,4'-diisocyanate (made by Wako Pure Chemical Industries, Ltd., isocyanate equivalent) was added to a reaction vessel with a volume of 1 liter that can be heated and cooled, equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction pipe. 125 g / eq): 125.00 g, cyclohexanone: 327.89 g, phenyl isocyanate (manufactured by Wako Pure Chemical Industries, Ltd., isocyanate equivalent; 119 g / eq): 14.88 g, 3-methyl-1-phenyl -2-phospholene-2-oxide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight; 192): 0.648 g was charged. The equivalent ratio of the reaction: the number of isocyanate groups of diphenylmethane-4,4′-diisocyanate / the number of isocyanate groups of phenyl isocyanate is 8.0. Next, introduction of nitrogen gas and stirring were started, the temperature was raised to 80 ° C., and a carbodiimidization reaction was performed at 80 ° C. for 5 hours. Then, a small amount of the reaction product was taken out from the reaction solution, and FT-IR measurement was performed. As a result, the peak at 2260 ± 5 cm ⁻¹ attributed to the isocyanate group disappeared, and the appearance of the peak at 2120 ± 5 cm ⁻¹ attributed to the generated carbodiimide group was confirmed. Next, the reaction solution was cooled to room temperature (20 ° C. to 23 ° C.) to obtain a solution of the carbodiimide compound (A-1).

-Production Example 2: Production of carbodiimide compound (A-2)-
Diphenylmethane-2,4′-diisocyanate (trade name; Millionate NM100, manufactured by Tosoh Corporation) was added to a reaction vessel with a volume of 1 liter which can be heated and cooled, equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction pipe. Isocyanate equivalent; 125 g / eq): 125.00 g, toluene: 336.05 g, 2,6-dimethylphenyl isocyanate (manufactured by Wako Pure Chemical Industries, Ltd., isocyanate equivalent; 147 g / eq): 18.38 g, 3-methyl-1-phenyl-2-phospholene-2-oxide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight; 192): 0.648 g was charged. The equivalent ratio of the reaction: the number of isocyanate groups in diphenylmethane-2,4′-diisocyanate / 2,6-dimethylphenyl isocyanate has 8.0 isocyanate groups. Next, introduction of nitrogen gas and stirring were started, the temperature was raised to 80 ° C., and a carbodiimidization reaction was performed at 80 ° C. for 5 hours. Then, a small amount of the reaction product was taken out from the reaction solution, and FT-IR measurement was performed. As a result, the peak at 2260 ± 5 cm ⁻¹ attributed to the isocyanate group disappeared, and the appearance of the peak at 2120 ± 5 cm ⁻¹ attributed to the generated carbodiimide group was confirmed. Next, the reaction solution was cooled to room temperature (20 ° C. to 23 ° C.) to obtain a solution of the carbodiimide compound (A-2).

-Production Example 3: Production of carbodiimide compound (A-3)-
2,4-tolylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd., isocyanate equivalent; 87 g) was added to a reaction vessel with a capacity of 1 liter which can be heated and cooled, equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction pipe. / Eq): 87.00 g, cyclohexanone: 290.43 g, phenyl isocyanate (manufactured by Wako Pure Chemical Industries, Ltd., isocyanate equivalent; 119 g / eq): 36.75 g, 3-methyl-1-phenyl-2 -Phosphorene-2-oxide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight: 192): 0.720 g was charged. The equivalent ratio of the reaction: the number of isocyanate groups of 2,4-tolylene diisocyanate / the number of isocyanate groups of phenyl isocyanate is 4.0. Next, introduction of nitrogen gas and stirring were started, the temperature was raised to 80 ° C., and a carbodiimidization reaction was performed at 80 ° C. for 5 hours. Then, a small amount of the reaction product was taken out from the reaction solution, and FT-IR measurement was performed. As a result, the peak at 2260 ± 5 cm ⁻¹ attributed to the isocyanate group disappeared, and the appearance of the peak at 2120 ± 5 cm ⁻¹ attributed to the generated carbodiimide group was confirmed. Next, the reaction solution was cooled to room temperature (20 ° C. to 23 ° C.) to obtain a solution of the carbodiimide compound (A-3).

(Examples 1 to 6, Comparative Examples 1 to 3)
Examples 1 to 6 are (A) the carbodiimide compound obtained in Production Examples 1 to 3 as a carbodiimide compound, (B) a compound having at least two epoxy groups in one molecule as a curing agent, and (C) an inorganic filler. Spherical silica (fused spherical silica), and if necessary, (D) maleimide compound having at least two maleimide groups in one molecule as maleimide compound, other filler, curing accelerator, flame retardant and methyl ethyl ketone as solvent The varnish having a solid content of 60% by mass was obtained by mixing at the blending ratio (parts by mass) shown in Table 1. In Comparative Examples 1 to 3, the resin materials shown in Table 2 were mixed at the blending ratio (parts by mass) shown in Table 2, and methyl ethyl ketone was used as a solvent to obtain a varnish having a solid content of 60% by mass. . Next, these varnishes were impregnated into 0.2 mm thick S glass cloth and dried by heating at 160 ° C. for 10 minutes to obtain a prepreg having a resin content of 55 mass%. Then, overlaid 4 sheets of the prepreg, the electrolytic copper foil of 12μm was placed on both sides, at a pressure 25 kg / cm ^2, performing 90 minutes pressed under the conditions of a temperature of 185 ° C., to obtain a copper-clad laminate . Using the copper-clad laminate thus obtained, the following evaluation items were measured and evaluated. Tables 3 and 4 show the evaluation results.

(1) Evaluation of copper foil adhesion (copper foil peel strength) A copper clad laminate is immersed in a copper etching solution to form a copper foil having a width of 1 cm and a length of 10 cm. The adhesiveness (peel strength) of the copper foil was measured using (Shimadzu Corporation EZTest (device name)).

(2) Measurement of glass transition temperature (Tg) A 5 mm square evaluation substrate was prepared by immersing a copper clad laminate in a copper etching solution to remove a copper foil on both sides, and a TMA (Thermal Mechanical Analysis) test apparatus (DuPont) The thermal expansion characteristics in the surface direction of the evaluation substrate were observed using TMA2940, manufactured by KK, and evaluated by the method defined in JIS K0129: 2005.

(3) Measurement of linear thermal expansion coefficient A 5-mm square evaluation board | substrate which removed the copper foil of both surfaces by immersing a copper clad laminated board in copper etching liquid was produced, and TMA test equipment (the Du Pont company make, TMA2940) was used. The linear thermal expansion coefficient at 30 ° C. to 100 ° C. in the plane direction of the evaluation substrate was measured.

(4) Evaluation of solder heat resistance A 5-cm square evaluation board from which copper foil on both sides was removed by immersing a copper-clad laminate in a copper etching solution was prepared using a pressure cooker test apparatus manufactured by Hirayama Manufacturing Co., Ltd. After performing pressure-cooker treatment for 4 hours under the conditions of 121 ° C. and 2 atm (0.2 MPa), the test substrate is immersed in a solder bath at a temperature of 300 ° C. for 20 seconds, and then the solder heat resistance is observed by observing the appearance. Sex was evaluated. When there was no visible blister, it was judged as “good”, and when there was a blister visible, it was judged as “blister”.

(5) Evaluation of heat resistance with copper A 5 mm square evaluation substrate was prepared from a copper clad laminate, and was subjected to a test method defined by IPC TM650 using a TMA test apparatus (manufactured by DuPont, TMA2940) at 300 ° C. Evaluation was made by measuring the time until the evaluation substrate bulges.

(6) Flame Retardancy Evaluation A test piece cut out to a length of 127 mm and a width of 12.7 mm was prepared from an evaluation substrate obtained by removing a copper foil on both sides by immersing a copper clad laminate in a copper etching solution, and UL94. It evaluated according to the test method (method V).

(7) Measurement of relative dielectric constant and dielectric loss tangent The obtained copper-clad laminate was immersed in a copper etching solution to prepare a 2 cm square evaluation substrate, and a relative dielectric constant measurement made by Hewlett-Packard Company was made. Using a device (product name: HP4291B), the relative dielectric constant and dielectric loss tangent at a frequency of 1 GHz were measured.

(8) Drill workability Φ0.105 mm (Union Tool MV J676) is used for the drill, the number of rotations is 160,000 min ⁻¹ , the feed rate is 0.8 m / min, the number of stacked sheets is one, and drilling is performed at 6000 An evaluation board was made by hitting, and the inner wall roughness of the drill hole was evaluated. The inner wall roughness was evaluated by performing electroless copper plating (plating thickness: 15 μm) and measuring the maximum value of the plating penetration length into the hole wall.

(9) Measurement of curing shrinkage rate A 5-mm square evaluation board from which copper foil on both sides was removed by immersing a copper clad laminate in a copper etching solution was used, and a TMA test apparatus (manufactured by DuPont, TMA2940) was used. The evaluation substrate was heated and cooled in the surface direction (heating from 20 ° C. to 260 ° C. (temperature increase rate 10 ° C./min) and cooling from 260 ° C. to 20 ° C. (temperature decrease rate 10 ° C./min)). The subsequent dimensional change rate was measured.

(10) Measurement of flexural modulus After removing the copper foil on both sides by immersing the copper-clad laminate in a copper etching solution, a test piece cut into a length of 40 mm, a width of 25 mm, and a thickness of 0.4 mm was prepared, The bending elastic modulus at room temperature (20 ° C. to 23 ° C.) was measured using a bending test apparatus (Orientec Co., Ltd., 5-ton Tensilon RTC-1350A).

The numbers in the table are indicated by mass parts of solid content. Further, “-” in the table indicates that the corresponding component is not contained.
Each order form shows the following.
(Curing agent)
* 1: Naphthol aralkyl-cresol copolymer epoxy resin (Nippon Kayaku Co., Ltd., trade name: NC-7000L)
* 2: Biphenyl aralkyl type epoxy resin (Nippon Kayaku Co., Ltd., trade name: NC-3000H)
(Inorganic filler)
* 3: Spherical silica (fused spherical silica, manufactured by Admatechs Co., Ltd., trade name: SO-25R, average particle size is 0.5 μm)
* 4: Spherical silica surface-treated with 1.0% by mass of 3-glycidoxypropyltrimethoxysilane to spherical silica with an average particle size of 0.5 μm or less (surface with 3-glycidoxypropyltrimethoxysilane) Treated fused spherical silica, manufactured by Admatechs Co., Ltd., trade name: SC-2050MTE, diluent solvent: methyl ethyl ketone)
* 5: Boehmite type aluminum hydroxide (manufactured by Kawai Lime Industry Co., Ltd., trade name: BMT-3L)
(Maleimide compound)
* 6: 2,2-bis (4- (4-maleimidophenoxy) phenyl) propane (manufactured by Daiwa Kasei Co., Ltd., trade name: BMI-4000)
* 7: Polyphenylmethane maleimide (manufactured by Daiwa Kasei Co., Ltd., trade name: BMI-2300)
(Other)
* 8: Inorganic flame retardant with zinc molybdate supported on talc (Sherwin Williams, trade name: Chemguard 1100)
* 9: Addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole (Daiichi Kogyo Seiyaku Co., Ltd., trade name: G-8809L)
* 10: Bisphenol A type cyanate resin (Lonza Japan, trade name: Primaset BADCy)

As is clear from the table, the copper clad laminates according to the examples are copper foil adhesion, glass transition temperature, solder heat resistance, linear thermal expansion coefficient, flame resistance, heat resistance with copper, relative permittivity, dielectric loss tangent. Excellent in all evaluation items of drilling workability, cure shrinkage rate and flexural modulus. On the other hand, the comparative examples are copper foil adhesion, glass transition temperature, solder heat resistance, linear thermal expansion coefficient, flame resistance, heat resistance with copper, relative dielectric constant, dielectric loss tangent, drill workability, cure shrinkage rate and flexural elasticity. The rate of any evaluation item is inferior.
A prepreg obtained by impregnating the resin composition of the present embodiment into a base material, and a laminate produced by laminating the prepreg are copper foil adhesiveness, glass transition temperature, solder heat resistance, thermal expansion coefficient, It is excellent in flame resistance, heat resistance with copper, relative dielectric constant, dielectric loss tangent, drill workability, curing shrinkage rate and bending elastic modulus, and is useful as a printed wiring board for electronic equipment.

All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

Claims

A prepreg containing a carbodiimide compound having at least one carbodiimide group in one molecule.
A prepreg having a peak at 2120 ± 5 cm −1 in the infrared absorption spectrum.
A resin composition containing a carbodiimide compound having at least one carbodiimide group in one molecule, a curing agent, and an inorganic filler.
The resin composition according to claim 3, wherein the carbodiimide compound includes an aromatic carbodiimide compound.
The resin composition according to claim 3 or 4, wherein the curing agent contains at least one selected from the group consisting of a carboxylic acid, an epoxy compound, a phenol compound, and an amine.
The resin composition according to any one of claims 3 to 5, wherein the inorganic filler contains silica.
The resin composition according to any one of claims 3 to 6, wherein the inorganic filler contains boehmite type aluminum hydroxide.
The resin composition according to any one of claims 3 to 7, wherein the inorganic filler has an average particle size of 5.0 μm or less.
The resin composition according to any one of claims 3 to 8, comprising a maleimide compound.
A prepreg comprising: a base material; and the resin composition according to any one of claims 3 to 9, which is impregnated in the base material.
A resin sheet obtained by molding the resin composition according to any one of claims 3 to 9 into a sheet shape.
A laminated board obtained by laminating the prepreg according to claim 1, claim 2 or claim 10.