JP6252929B2 - Method for producing resin composition - Google Patents

Description

The present invention relates to a process for preparing are that tree fat compositions used as a material for a printed wiring board.

  Conventionally, printed wiring boards used in electronic devices have been improved in heat resistance by improving glass transition temperature (Tg) and the like, and have been made flame retardant. In recent years, particularly in the field of small electronic devices such as mobile devices, as the devices become smaller, thinner, and more multifunctional, the printed circuit board is further reduced in dielectric constant and CTE (coefficient of thermal expansion). Market demand for expansion coefficient is increasing. Generally, an epoxy resin composition is used as an insulating material for a printed wiring board. In this epoxy resin composition, a phenolic curing agent, a diamine curing agent, a cyanate curing agent, an acid anhydride is used as a curing agent for the epoxy resin. A physical curing agent or the like is used. Of these various curing agents, acid anhydride curing agents are known to be effective in reducing the dielectric constant. Conventionally used acid anhydride curing agents include polyfunctional acid anhydride compounds having a plurality of acid anhydride rings in one molecule, styrene / maleic acid copolymer (SMA), and the like. . For example, Patent Document 1 describes the use of a copolymer (SMA) containing styrene and maleic anhydride as essential components as an acid anhydride curing agent.

  However, when the above-mentioned polyfunctional acid anhydride compound is used as a curing agent for epoxy resin, it cannot sufficiently meet the required level of the market in order to achieve a low dielectric constant, and the adhesive strength such as peel strength is not good. Somewhat inferior. SMA is more effective in reducing the dielectric constant than polyfunctional acid anhydride compounds, but has a problem of low peel strength.

JP-A-9-194610

The present invention has been made in view of the above, it is possible to realize a high glass transition temperature, lower dielectric constant, to provide a method for producing dendritic fat composition Ru can increase peel strength Objective.

  The inventors of the present application, as a result of intensive studies to solve the above problems, first focused on a monofunctional acid anhydride as a curing agent capable of reducing the dielectric constant. As a result, when a monofunctional acid anhydride is used as a curing agent for an epoxy resin, a high glass transition temperature can be achieved, a low dielectric constant can be achieved, and a peel strength can be improved. I understood. On the other hand, monofunctional acid anhydrides have volatility due to their relatively low molecular weight. Therefore, in the process of manufacturing a prepreg by impregnating a resin composition into a substrate and drying it, It was also found that part of the anhydride volatilized and disappeared. If a part of the monofunctional acid anhydride volatilizes in this way, the component ratio of the resin composition may change greatly between before and after manufacturing the prepreg. There was concern that the properties would be adversely affected. Accordingly, the inventors of the present application have further studied, and as a result, the present invention has been completed as follows.

In the method for producing a resin composition according to the present invention, an epoxy resin and a monofunctional acid anhydride are blended in an equivalent ratio of 1: 0.5 to 1.5, and a preliminary reaction product is obtained by advancing the preliminary reaction. And a step of adding an inorganic filler to the preliminary reaction product, and the ring-opening rate of the monofunctional acid anhydride in the preliminary reaction product is 10% or more and less than 65% It is characterized by.
In the method for producing the resin composition, the preliminary reaction is preferably performed at a temperature of 60 to 80 ° C.

  According to the present invention, since the epoxy resin and the monofunctional acid anhydride are pre-reacted, volatilization of the monofunctional acid anhydride can be suppressed, a high glass transition temperature is realized, and a low dielectric constant is achieved. It is possible to increase the rate and improve the peel strength.

  Embodiments of the present invention will be described below.

  The resin composition according to the embodiment of the present invention contains an epoxy resin and a curing agent.

  Examples of the epoxy resin include naphthalene type epoxy resin, phosphorus-containing epoxy resin, dicyclopentadiene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A. A novolac type epoxy resin, a biphenyl type epoxy resin, an alicyclic epoxy resin, a diglycidyl ether compound of a polyfunctional phenol, a diglycidyl ether compound of a polyfunctional alcohol, or the like can be used. An epoxy resin can use only 1 type, or can use 2 or more types together. In particular, when a phosphorus-containing epoxy resin is used, the phosphorus content in the resin composition can be increased, thereby improving the flame retardancy.

  The resin composition according to this embodiment includes a monofunctional acid anhydride as a curing agent. The monofunctional acid anhydride is an acid anhydride having only one cyclic acid anhydride group (—COOCO—) as a functional group. Examples of monofunctional acid anhydrides include acid anhydrides such as dicarboxylic acid compounds, and more specific examples include maleic anhydride, phthalic anhydride, 4-methylhexahydrophthalic anhydride, and hexahydrophthalic anhydride. Acid, methylbicyclo [2.2.1] heptane-2,3-dicarboxylic anhydride, bicyclo [2.2.1] heptane-2,3-dicarboxylic anhydride, 1,2,3,6-tetrahydro Examples thereof include phthalic anhydride. Furthermore, examples of the monofunctional acid anhydride include acid anhydrides such as tricarboxylic acid compounds, and more specifically, for example, trimellitic acid anhydride. Among these, 4-methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylbicyclo [2.2.1] heptane-2,3-dicarboxylic anhydride, bicyclo [2.2.1] heptane-2, An alicyclic acid anhydride such as 3-dicarboxylic acid anhydride and 1,2,3,6-tetrahydrophthalic anhydride is suitable for reducing the dielectric constant. In the present embodiment, the monofunctional acid anhydride is pre-reacted and used as described later. Therefore, when a monofunctional acid anhydride having a boiling point of 150 ° C. or lower, preferably 130 ° C. or lower is used, its volatilization is performed. It is particularly effective in effectively suppressing the property. Further, since the monofunctional acid anhydride as a curing agent has a relatively small molecular weight compared to SMA and the like, it is effective in suppressing an increase in varnish viscosity. For example, a monofunctional acid anhydride having a weight average molecular weight of 400 or less is effective. It is preferable to use a product. When such a monofunctional acid anhydride is used, the dielectric constant (specific dielectric constant (Dk)) of the cured product can be lowered and the peel strength can be increased as compared with the case where a polyfunctional acid anhydride is used. Can do. A monofunctional acid anhydride can use only 1 type, or can use 2 or more types together. As long as the effects of the present invention are not impaired, a curing agent other than the monofunctional acid anhydride may be contained in the organic component.

  In the resin composition according to the present embodiment, the epoxy resin and the monofunctional acid anhydride are used as a preliminary reaction product obtained by reacting them in advance.

  In the preliminary reaction product, the epoxy resin and the monofunctional acid anhydride are blended so that the equivalent ratio of the epoxy resin to the monofunctional acid anhydride is 1: 0.5 to 1.5. When the equivalent ratio of the monofunctional acid anhydride to the epoxy resin is less than 0.5, the monofunctional acid anhydride as a curing agent is insufficient, the glass transition temperature of the cured product is lowered, and the heat resistance is deteriorated. There is also a risk that the dielectric constant may not be sufficiently lowered. In addition, when the equivalent ratio of the monofunctional acid anhydride to the epoxy resin exceeds 1.5, the unreacted monofunctional acid anhydride tends to remain excessively, so that the glass transition temperature of the cured product decreases. The heat resistance may deteriorate and the flame retardancy may decrease. The equivalent ratio of the epoxy resin to the monofunctional acid anhydride is preferably 1: 0.7 to 1.3.

  Furthermore, in the preliminary reaction product, the epoxy resin and the monofunctional acid anhydride are reacted so that the ring opening rate of the monofunctional acid anhydride is 10% or more and less than 65%. Preferably, in the preliminary reaction product, the ring opening rate of the monofunctional acid anhydride is 25% or more and 35% or less.

The ring opening rate of the monofunctional acid anhydride can be calculated, for example, as follows. First, a varnish (primary varnish described later) is prepared by mixing at least an epoxy resin to be pre-reacted and a monofunctional acid anhydride and dissolving them in a solvent. At this time, although a hardening accelerator may be mix | blended with the said varnish, it does not mix | blend the other organic component which has reactivity with an epoxy resin. Next, infrared absorption spectra before and after heating of the varnish are measured. Then, the seek area before heating peaks due to cyclic anhydride groups in the vicinity of 1800~1900cm ^-1 _{(A 1)} and the area after heating _{(A 2),} which is the peak of the internal standard 1500~1530cm The area before heating (B ₁ ) and the area after heating (B ₂ ) of the peak due to the benzene ring near ⁻¹ are determined. The ring opening rate of the monofunctional acid anhydride can be calculated by substituting the area of each peak thus determined into the following equation.

Ring opening rate of monofunctional acid anhydride (%) = {1- (A ₂ / B ₂ ) / (A ₁ / B ₁ )} × 100
When the ring-opening rate of the monofunctional acid anhydride is less than 10%, an unreacted monofunctional acid anhydride remains excessively, so that the monofunctional acid anhydride volatilizes and easily disappears during the production of the prepreg. As a result, it is considered that the curing agent is insufficient and the crosslinking density of the cured product of the resin composition is lowered, and the heat resistance may be deteriorated, for example, the glass transition temperature (Tg) of the cured product is lowered. In addition, when the ring opening rate of the monofunctional acid anhydride is 65% or more, the reaction at the time of the preliminary reaction proceeds too much, the preliminary reaction product is polymerized, and the resin composition is gelled to produce a prepreg. May become difficult. Since the ring-opening rate of the monofunctional acid anhydride varies depending on the heating temperature and heating time at the time of preparing the base varnish, the heating conditions are appropriately adjusted so as to be 10% or more and less than 65%. The conditions for this preliminary reaction can be appropriately set by sampling the reaction product over time while performing the preliminary reaction and confirming the ring-opening rate.

  As described above, the resin composition contains a preliminary reaction product obtained by reacting an epoxy resin and a monofunctional acid anhydride in advance.

  Further, the resin composition may contain a flame retardant, a curing accelerator and the like.

  As the flame retardant, a halogen flame retardant or a non-halogen flame retardant can be used. As the non-halogen flame retardant, for example, a phosphorus-containing flame retardant can be used. In the case of using this phosphorus-containing flame retardant, the phosphorus content is preferably 1.0% by mass or more based on the total amount of organic components of the resin composition in order to obtain good flame retardancy. The upper limit of the phosphorus content is not particularly limited, but if a phosphorus-containing flame retardant exceeding the necessary and sufficient content for imparting flame retardancy is used, the electrical characteristics, heat resistance and the like may be reduced. The phosphorus content is preferably 5.0% by mass or less based on the total amount of the organic components. Further, the phosphorus-containing flame retardant is preferably a reactive phosphorus-containing flame retardant having a functional group that reacts with an acid anhydride group or a carboxy group (—COOH). The acid anhydride group in this case is, for example, an acid anhydride group possessed by an unreacted monofunctional acid anhydride, and the carboxy group is, for example, a monofunctional acid when an epoxy resin and a monofunctional acid anhydride are reacted. It is a carboxy group formed by ring opening of an anhydride acid anhydride group. Therefore, specific examples of the functional group possessed by the reactive phosphorus-containing flame retardant include a hydroxy group and an amino group. Monofunctional acid anhydrides tend to reduce the flame retardancy of the cured product because they contain many oxygen atoms. However, when the above-mentioned reactive phosphorus-containing flame retardant is reacted with the monofunctional acid anhydride, Since a phosphorus atom can be present near the atom, flame retardancy can be improved. A flame retardant can use only 1 type, or can use 2 or more types together. As long as the effects of the present invention are not impaired, a molten phosphorus-containing flame retardant that does not react with a monofunctional acid anhydride, a dispersed phosphorus-containing flame retardant, or a flame retardant that does not contain phosphorus may be used. The molten phosphorus-containing flame retardant dissolves in the resin composition and becomes a homogeneous system. Specific examples thereof include phosphazene. The dispersed phosphorus-containing flame retardant is dispersed without being dissolved in the resin composition and becomes a heterogeneous system. Specific examples thereof include aluminum phosphinate that is a metal phosphate.

  As the curing accelerator, for example, an imidazole compound such as 2-ethyl-4-methylimidazole (2E4MZ) can be used. The content of the curing accelerator is not particularly limited as long as the effects of the present invention are not impaired.

  Further, the resin composition may contain an inorganic filler and the like. As the inorganic filler, for example, silica such as spherical silica and crushed silica, metal hydroxide such as aluminum hydroxide and magnesium hydroxide, and the like can be used. The content of such an inorganic filler can be appropriately determined in consideration of the balance of low dielectric constant and low CTE, and is not particularly limited.

  And a resin composition can be prepared as a resin varnish as follows.

  First, a varnish (primary varnish) in which an epoxy resin to be pre-reacted and a monofunctional acid anhydride are blended and dissolved in a solvent is prepared. At this time, the primary varnish can also contain organic components that do not react directly with the epoxy resin or monofunctional acid anhydride, such as a curing accelerator or a non-reactive flame retardant. Other organic components reactive with the product (for example, the curing agent when using other curing agents and reactive flame retardants) are not added to the primary varnish, but after the preliminary reaction Mix. Thus, the component mix | blended after a preliminary reaction is called a post-mixing component below. The primary varnish is preliminarily reacted by heating at 60 to 80 ° C. for 1 to 5 hours while stirring with a stirrer such as a disper so that the solid content (non-solvent component) concentration is 60 to 80% by mass. To advance. Thereby, the preliminary reaction product which the epoxy resin and the monofunctional acid anhydride reacted produced | generated in a primary varnish. Here, the correlation between the heating temperature and reaction time, which are preliminary reaction conditions, and the ring-opening rate of the monofunctional anhydride should be experimentally grasped in advance by sampling as described above. Thus, by adjusting the preliminary reaction conditions, the ring opening rate of the monofunctional acid anhydride in the reaction product can be made 10% or more and less than 65%. In addition, said heating temperature and heating time are examples. Solvents used for the preparation of the varnish include, for example, ethers such as ethylene glycol monomethyl ether, ketones such as acetone and methyl ethyl ketone (MEK), and aromatic hydrocarbons such as benzene and toluene. A solvent that is not reactive with the functional acid anhydride can be used. On the other hand, it is desirable to avoid the use of a solvent having a hydroxyl group, such as an alcohol solvent, because it is reactive with an acid anhydride. And when there is no said post-blending component, the primary varnish after a preliminary reaction can be made into a base varnish as it is. On the other hand, when there is the above-mentioned after-blending component, the base varnish can be prepared by adding the after-blending component to the primary varnish and adding and mixing a solvent as required. In addition, a base varnish is a varnish which mix | blended the organic component except inorganic components, such as an inorganic filler.

  Thereafter, when an inorganic component such as an inorganic filler is not blended, the base varnish can be used as it is as a resin varnish for producing a prepreg. On the other hand, when an inorganic component is blended, the resin varnish can be prepared by blending the inorganic component with the base varnish and further stirring and mixing at 20 to 40 ° C. for 1 to 3 hours for homogenization.

  In this embodiment, the resin varnish of the resin composition obtained as described above is impregnated into a substrate such as glass cloth, and this is heated and dried at 110 to 140 ° C. to remove the solvent in the resin varnish. A prepreg can be produced by semi-curing the resin composition. At this time, since a part of the monofunctional acid anhydride is preliminarily reacted with the epoxy resin to become a pre-reaction product, the monofunctional acid anhydride is less likely to volatilize even during the heating and drying described above, and is semi-cured as a prepreg. Most of the resin composition remains in the state. The heat drying is preferably performed so that the prepreg has a gel time of 60 to 120 seconds. The gel time of the prepreg is the time from immediately after placing the semi-cured resin composition collected from the prepreg on a plate heated to 170 ° C. until the resin composition gels. The resin content (content of the resin composition) of the prepreg is preferably 30 to 80% by mass with respect to the total amount of the prepreg.

  In this embodiment, a laminated board can be manufactured by laminating the prepreg formed as described above with a metal foil and performing heat and pressure molding. For example, a laminate is manufactured as a metal-clad laminate such as a copper-clad laminate by laminating a plurality of prepregs and a metal foil such as a copper foil on the outside and laminating the laminate by heating and pressing it. Can do. In the laminate, the cured product of the prepreg forms an insulating layer. Since the cured resin layer of the insulating layer is formed of a cured product of the resin composition, the glass transition temperature can be increased and the heat resistance can be improved. Furthermore, since a monofunctional acid anhydride is used, the dielectric constant of the insulating layer can be reduced compared to the case where a polyfunctional acid anhydride is used, and the adhesion between the insulating layer and the metal foil is improved. Peel strength can be increased. The heating and pressing conditions are, for example, 140 to 200 ° C., 0.5 to 5.0 MPa, and 40 to 240 minutes.

  A printed wiring board can be manufactured by forming a conductor pattern on the laminated board obtained as described above. For example, a printed wiring board can be manufactured by forming a conductor pattern on the surface of a metal-clad laminate using a subtractive method. Furthermore, when this printed wiring board is used as a core material (inner layer material), a multilayer printed wiring board can be manufactured. That is, the conductor pattern (inner layer pattern) of the core material is roughened by black oxidation or the like, and then a metal foil is stacked on the surface of the core material via a prepreg, and this is heated and pressed to be laminated. The heating and pressing conditions at this time are, for example, 140 to 200 ° C., 0.5 to 5.0 MPa, and 40 to 240 minutes. Next, after drilling and desmearing, a subtractive method is used to form a conductor pattern (outer layer pattern) and plating the inner wall of the hole to form a through hole. A printed wiring board can be manufactured. The number of layers of the printed wiring board is not particularly limited.

  In the printed wiring board described above, since the dielectric constant of the insulating layer is lowered, when transmitting a signal using the conductor pattern, it is possible to increase the signal speed and process a large amount of information at a high speed.

  Hereinafter, the present invention will be specifically described by way of examples.

(Epoxy resin)
The following were used as an epoxy resin.

“HP9500” manufactured by DIC Corporation, which is a naphthalene type epoxy resin (epoxy equivalent: 230 g / eq, softening point: 106 ° C.)
“FX-289-P” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., which is a phosphorus-containing epoxy resin (epoxy equivalent: 390 g / eq, phosphorus content: 3.5 wt%)
(Curing agent)
The following were used as curing agents.

“Ricacid MH-700” (4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30) manufactured by Shin Nippon Rika Co., Ltd., which is a monofunctional acid anhydride (liquid alicyclic acid anhydride, acid anhydride) (Equivalent: 161-166 g / eq, neutralization value: 660-675 KOH mg / g, freezing point: 20 ° C.)
“Ricacid HNA-100” (Methylbicyclo [2.2.1] heptane-2,3-dicarboxylic acid anhydride / bicyclo [2.2.1] heptane-manufactured by Nippon Kayaku Co., Ltd., which is a monofunctional acid anhydride 2,3-dicarboxylic acid anhydride) (liquid alicyclic acid anhydride, acid anhydride equivalent: 174 to 184 g / eq, freezing point -5 ° C. or lower)
“B-4500” manufactured by DIC Corporation, which is an alicyclic polyfunctional acid anhydride (powdered acid anhydride, acid anhydride equivalent: 132 g / eq)
“SMA 2000” manufactured by CRAY VALLEY, which is a polyfunctional acid anhydride (styrene / maleic anhydride copolymer with styrene: maleic anhydride = 2: 1, styrene maleic anhydride resin, neutralization value: 355 KOH mg / g, (Weight average molecular weight: 7500)
“SMA EF-30” manufactured by CRAY VALLEY, a polyfunctional acid anhydride (styrene / maleic anhydride copolymer with styrene: maleic anhydride = 3: 1, styrene maleic anhydride resin, neutralization value: 280 KOHmg / g, weight average molecular weight: 9500)
(Flame retardants)
The following were used as flame retardants.

“SPB-100” manufactured by Otsuka Chemical Co., Ltd., a molten phosphorus-containing flame retardant (phosphazene, phosphorus content: 13 wt%)
“OP-935” manufactured by Clariant Japan Co., Ltd., a dispersed phosphorus-containing flame retardant (aluminum phosphinate, phosphorus content: 23 wt%)
“HPC-9100” manufactured by DIC Corporation, which is a reactive phosphorus-containing flame retardant (phosphorus content: 10 to 11 wt%, softening point: 133 to 147 ° C.)
“Emerald 2000” (phosphorus content: 9.8 wt%) manufactured by Chemtura Japan, which is a reactive phosphorus-containing flame retardant
(Curing accelerator)
The following were used as the curing accelerator.

2-Ethyl-4-methylimidazole (2E4MZ)
(Inorganic filler)
The following were used as inorganic fillers.

"Megasil 525" made by Sibelco Japan Co., Ltd., which is a melt-crushed silica
"CL-303M" manufactured by Sumitomo Chemical Co., Ltd., which is aluminum hydroxide
(Resin composition)
In Examples 1 to 18 and Comparative Examples 1, 2, 6, and 7, the above epoxy resin, monofunctional acid anhydride and curing accelerator were blended in the blending amounts (parts by mass) shown in Tables 1 and 2, and the solvent (MEK) is diluted so that the solid content (non-solvent component) concentration is 60 to 80% by mass, and heated at 60 to 80 ° C. for 1 to 5 hours while stirring with a disper, A primary varnish containing a pre-reaction product reacted with a portion of the monofunctional acid anhydride was prepared. The infrared absorption spectrum before and after heating of this primary varnish was measured, and the ring opening rate of the acid anhydride was calculated. The results are shown in Tables 1 and 2. Furthermore, the base varnish was prepared by mix | blending a flame retardant with said primary varnish by the compounding quantity (mass part) shown in Table 1 and Table 2, and stirring and mixing and equalizing.

  In Comparative Examples 3 to 5, the above epoxy resin, curing agent, flame retardant, and curing accelerator were blended in the blending amounts (parts by mass) shown in Tables 1 and 2, and the solid content (non-solvent component) in the solvent (MEK) ) A base varnish was prepared by diluting to a concentration of 60 to 80% by mass and stirring and mixing at 20 to 40 ° C. for 1 to 3 hours while stirring with a disper for 1 to 3 hours.

  Next, the inorganic filler is blended in the base varnish in the blending amounts (parts by mass) shown in Table 1 and Table 2, and further stirred and mixed at 20 to 40 ° C. for 1 to 3 hours to make the example 1 uniform. Resin varnishes of -18 and Comparative Examples 1-7 were prepared. In addition, the resin varnish of the comparative example 2 was gelatinized and the prepreg could not be manufactured.

(Prepreg)
The prepreg impregnates the resin varnish of the above resin composition into a glass cloth (“7628 type cloth” manufactured by Nitto Boseki Co., Ltd.) as a base material, and heats it at 110 to 140 ° C. by a non-contact type heating unit. It dried and removed the solvent in a resin varnish, and manufactured by semicuring the resin composition. The resin content of the prepreg (content of the resin composition) is 65 to 75% by mass with respect to the total amount of the prepreg.

(Laminated board)
The laminated plate is made of 8 sheets of prepreg (340mm x 510mm) and copper foil (Mitsui Metal Mining Co., Ltd., thickness 18μm, ST foil) with a roughened surface on both sides. Then, it was manufactured as a copper-clad laminate by lamination molding. The heating and pressing conditions are 180 ° C., 2.94 MPa, and 60 minutes. The prepreg of Comparative Example 1 could not produce a laminate.

(Glass-transition temperature)
The glass transition temperature of the prepreg was measured using a viscoelastic spectrometer “DMS6100” manufactured by Seiko Instruments Inc. Specifically, the measurement was performed with a bending module at a frequency of 10 Hz, and the glass transition temperature was defined as the temperature at which tan α was maximized when the temperature was raised from room temperature to 280 ° C. under a temperature rising rate of 5 ° C./min.

(Relative permittivity (Dk))
Using a “impedance / material analyzer 4291A” manufactured by Hewlett-Packard, the relative dielectric constant of the copper-clad laminate at 1 GHz was measured according to IPC-TM-650 2.5.5.9.

(Peel strength)
The peel strength of the copper foil on the surface of the copper clad laminate was measured in accordance with JIS C 6481. That is, the copper foil was peeled off at a speed of about 50 mm per minute, and the peel strength at that time (kN / m) was measured as the peel strength.

(Flame retardance)
Copper-clad laminates with plate thicknesses of 0.8 mm, 1.2 mm, and 1.6 mm were manufactured in the same manner as described above by adjusting the number of prepregs. After removing the copper foil on the surface of each copper clad laminate by etching, a flame retardancy test was performed according to “Test for Flammability of Plastic Materials-UL 94” of Underwriters Laboratories to evaluate the flame retardancy. Those satisfying V-0 are “OK”, and those not satisfying are “NG”. Tables 1 and 2 show the plate thickness and whether the plate thickness satisfies V-0.

表１及び表２から明らかなように、各比較例のものに比べて、各実施例のものは、ガラス転移温度が高く、誘電率が低く、ピール強度が高く、難燃性が総じて高く、各特性が良好なレベルでバランスよく得られていることが確認された。

As is apparent from Tables 1 and 2, each example has a higher glass transition temperature, a lower dielectric constant, a higher peel strength, and a higher flame retardancy as a whole than the comparative examples. It was confirmed that each characteristic was obtained with a good level and a good balance.

  On the other hand, in Comparative Example 1 where the ring-opening rate of the monofunctional acid anhydride in the preliminary reaction is as low as 5%, adhesion between the prepregs or between the prepreg and the copper foil during the production of the laminated board Since the property was very low and peeling occurred, it was not possible to obtain a laminate that can be evaluated for performance. It is inferred that most of the monofunctional acid anhydride remained in an unreacted monomer state, resulting in insufficient curing and poor molding due to volatilization of the monofunctional acid anhydride.

  Further, in Comparative Example 2 in which the ring opening rate of the monofunctional acid anhydride in the preliminary reaction was as large as 65%, the varnish gelled and a prepreg could not be produced.

  Further, in Comparative Example 3 using a polyfunctional acid anhydride without using a monofunctional acid anhydride as a curing agent, the glass transition temperature was low and the dielectric constant (Dk) was slightly high.

  In Comparative Examples 4 and 5 using SMA without using a monofunctional acid anhydride as a curing agent, although the dielectric constant was as low as each example, the glass transition temperature was low and the peel strength was inferior. Met.

  Further, in Comparative Example 6 in which the equivalent ratio of the monofunctional acid anhydride to the epoxy resin is less than 0.5, the monofunctional acid anhydride as the curing agent is insufficient, resulting in insufficient curing, and the crosslink density of the cured product of the resin composition is low. Inferred to be lower. Therefore, it is considered that the glass transition temperature is low and the flame retardancy is also lowered.

  Further, in Comparative Example 7 in which the equivalent ratio of the monofunctional acid anhydride to the epoxy resin exceeds 1.5, since the monofunctional acid anhydride is excessively contained, unreacted monofunctional acid anhydride remains. It is thought that the glass transition temperature was lowered, and the flame retardancy was also lowered because there were many monofunctional acid anhydrides containing many oxygen atoms. Furthermore, the proportion of polar groups such as carboxyl groups generated by the primary reaction between the epoxy resin and the acid anhydride does not contribute to the three-dimensional crosslinking reaction has increased, and the dielectric constant has also increased slightly. Conceivable.

Claims (2)

A step of blending an epoxy resin and a monofunctional acid anhydride in an equivalent ratio of 1: 0.5 to 1.5 and generating a preliminary reaction product by advancing the preliminary reaction;
Blending an inorganic filler with the preliminary reaction product,
The method for producing a resin composition, wherein the ring opening rate of the monofunctional acid anhydride in the preliminary reaction product is 10% or more and less than 65%. The preliminary reaction, method for producing a resin composition according to claim 1, characterized in that at a temperature of 60-80 ° C..