Resin composition, resin film material, and printed wiring board

Abstract

The present disclosure addresses the problem of providing a resin composition which is capable of achieving suitable flame retardancy, and is capable of achieving good insulation characteristics without impairing handleability in the cases where the resin composition is formed into a film form. This resin composition contains a thermosetting resin component (A), a phosphorus-containing flame retardant (B), and an inorganic filler (C). The component (A) contains a liquid epoxy resin (a1) that has a viscosity of 50,000 mPa or less at 25°C. The component (B) contains an aromatic condensed phosphoric acid ester compound (b1) that has a melting point of 40°C or less and an acid value of 0.25 KOHmg / g or less. The content of the component (B) is 10% by mass to 30% by mass inclusive with respect to the total amount of the component (A) and the component (B). The content of the component (b1) is 10% by mass to 100% by mass inclusive with respect to the total amount of the component (B). The content of the component (C) is 200 parts by mass to 900 parts by mass inclusive with respect to a total of 100 parts by mass of the component (A) and the component (B).

Description

Resin composition, resin film material, and printed wiring board

[0001] The present disclosure relates to a resin composition, a resin film material, and a printed wiring board.

[0002] Printed wiring boards are widely used in various fields, such as electronic devices, communication devices, computers, etc. Various proposals have been made to improve various properties in accordance with the specific applications and purposes in each field.

[0003] Printed wiring boards used in electronic devices connected to power sources with large current capacities, such as automotive power supplies, are required to support high currents and high outputs and to have suitable heat dissipation properties. To meet these requirements, it is conceivable to arrange inner layer circuits with thicknesses exceeding 100 μm inside a multilayer printed wiring board. However, this approach makes it difficult to sufficiently fill the thick conductor inner layer circuits with insulating resin materials, leading to other problems such as the likelihood of voids and cracks occurring due to insufficient filling. Furthermore, prepregs, which are fiber substrates such as glass cloth impregnated with an insulating resin composition, are commonly used to form the insulating layer of multilayer printed wiring boards. However, when attempting to fill the thick conductor inner layer circuits using this prepreg, the insulating resin is consumed in filling the inner layer circuit side, leaving the opposite side of the glass cloth insufficient, which can lead to cross-touch, where the surface circuit of the multilayer printed wiring board comes into direct contact with the glass cloth, resulting in concerns about reduced insulation reliability.

[0004] To solve this problem, Patent Document 1 proposes a printed wiring board with built-in thick conductors, in which a resin film that does not contain glass cloth is layered on an inner layer circuit board having a thick conductor circuit, and then a prepreg containing a fiber base material is layered on top of that and molded and pressed to form an insulating layer. In this board, the resin film that does not contain glass cloth ensures the filling ability of the thick conductor circuit side, while also solving the problem of cross touch.

[0005] According to the inventor's own research, the configuration of Patent Document 1 can suppress deterioration of long-term connection and insulation reliability due to cross-touch, but the use of a resin film increases the resin ratio of the entire insulation layer, leaving room for improvement in terms of flame retardancy. Therefore, while it is conceivable to improve flame retardancy by increasing the content of flame retardant in the resin film, there are concerns that as the amount of flame retardant that is not a resin component increases, the flexibility of the resin film may be impaired and the phenomenon of cutting chips falling off the cut surface (powder fall) may become more likely to occur, resulting in a decrease in the handleability of the resin film. Furthermore, other properties such as insulation characteristics may also be affected.

[0006] Recently, due to growing environmental awareness, halogen-free flame retardants that do not contain halogen elements have been used as a flame retardant technology for printed wiring boards. Phosphorus-containing flame retardants are commonly used as halogen-free flame retardants, but these phosphorus-containing flame retardants often need to be blended in relatively larger amounts than halogen-based flame retardants to achieve a satisfactory flame retardant effect. Therefore, when using phosphorus-containing flame retardants, it is necessary to consider the impact on other properties when increasing the blending amount in the insulating resin material.

[0007] Furthermore, insulating resin materials generally contain inorganic fillers and the like in order to optimize the linear expansion coefficient of the insulating layer, which is the cured product, and to improve its physical strength. However, when the insulating resin material is used in the form of a resin film, the inorganic fillers, like flame retardants, also cause a decrease in flexibility as the content increases. Therefore, when increasing the amount of flame retardant to improve flame retardancy, it is necessary to consider the balance with the amount of inorganic filler used.

[0008] As described above, when improving flame retardancy by adjusting the content of flame retardant, there is a trade-off with other properties. Therefore, rather than simply considering the amount of flame retardant used, it is necessary to consider the component design as a whole.

[0009] Patent No. 6960595

[0010] In view of the above circumstances, an object of the present disclosure is to provide a resin composition that can achieve suitable flame retardancy, can achieve good insulating properties without compromising handleability when made into a film form, and a resin film material and a printed wiring board produced using the same.

[0011] A resin composition according to one embodiment of the present disclosure contains a thermosetting resin component (A), a phosphorus-containing flame retardant (B), and an inorganic filler (C). The thermosetting resin component (A) contains a liquid epoxy resin (a1) having a viscosity of 50,000 mPa or less at 25°C. The phosphorus-containing flame retardant (B) contains an aromatic condensed phosphate ester compound (b1) having a melting point of 40°C or less and an acid value of 0.25 KOH mg / g or less. The content of the phosphorus-containing flame retardant (B) is 10% by mass or more and 30% by mass or less, based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B). The content of the aromatic condensed phosphate ester compound (b1) is 10% by mass or more and 100% by mass or less, based on the total amount of the phosphorus-containing flame retardant (B). The content of the inorganic filler (C) is 200 parts by mass or more and 900 parts by mass or less relative to 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

[0012] A resin film material according to one embodiment of the present disclosure includes a carrier film and a resin layer that is overlaid on the carrier film and that contains an uncured or semi-cured product of the resin composition.

[0013] A printed wiring board according to an embodiment of the present disclosure includes a conductor wiring and an insulating layer overlying the conductor wiring, the insulating layer including a cured product of the resin composition.

[0014] Fig. 1 is a schematic cross-sectional view showing a resin film material according to an embodiment of the present disclosure. Fig. 2A is a schematic cross-sectional view showing the same resin film material and a core material superimposed thereon. Fig. 2B is a schematic cross-sectional view showing the same resin film material and a core material superimposed thereon. Fig. 3A is a schematic cross-sectional view showing a laminate including a resin layer containing an uncured or semi-cured product of a resin composition according to an embodiment of the present disclosure. Fig. 3B is a schematic cross-sectional view showing a printed wiring board according to an embodiment of the present disclosure.

[0015] The resin composition, resin film material 10, and printed wiring board 5 according to this embodiment will be described below in order.

[0016] The resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains a thermosetting resin component (A), a phosphorus-containing flame retardant (B), and an inorganic filler (C).

[0017] The thermosetting resin component (A) contains a liquid epoxy resin (a1) having a viscosity at 25°C of 50,000 mPa or less.

[0018] The phosphorus-containing flame retardant (B) contains an aromatic condensed phosphate ester compound (b1) having a melting point of 40° C. or lower and an acid value of 0.25 KOH mg / g or lower.

[0019] The content of the phosphorus-containing flame retardant (B) is 10% by mass or more and 30% by mass or less based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

[0020] The content of the aromatic condensed phosphate ester compound (b1) is 10% by mass or more and 100% by mass or less based on the total amount of the phosphorus-containing flame retardant (B).

[0021] The content of the inorganic filler (C) is 200 parts by mass or more and 900 parts by mass or less per 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

[0022] By using composition (X), it is possible to obtain a resin film material 10 that ensures flexibility and is capable of preventing powder falling off, and to obtain a cured product that has excellent flame retardancy and insulating properties.

[0023] According to the composition (X) of this embodiment, the phosphorus-containing flame retardant (B) can enhance the flame retardancy of the cured product of the composition (X).

[0024] Since the composition (X) according to this embodiment has enhanced flame retardancy due to the inclusion of the phosphorus-containing flame retardant (B), the composition (X) and its cured product can also be made into a halogen-free material. The definition of a halogen-free material is based on the standard (JPCA-ES01) of the JPCA (Japan Electronics Packaging and Circuits Association).

[0025] The resin film material 10 according to this embodiment is formed using composition (X). The resin film material 10 includes a carrier film 7 and a resin layer 1 that is overlaid on the carrier film 7 and contains an uncured or semi-cured resin composition.

[0026] [Resin Composition] <Thermosetting Resin Component (A)> The thermosetting resin component (A) is a resin component having thermosetting properties. The thermosetting resin component (A) contains a liquid epoxy resin (a1) having a viscosity of 50,000 mPa or less at 25°C. The viscosity is measured using a Brookfield viscometer with a standard spindle No. 3 at a rotation speed of 60 rpm.

[0027] The viscosity of the liquid epoxy resin (a1) at 25° C. is preferably 25,000 mPa·s or less, and more preferably 10,000 mPa·s or less. With such a viscosity, the flexibility of the resin layer 1 can be ensured and powder falling can be prevented.

[0028] On the other hand, the viscosity of the liquid epoxy resin (a1) at 25° C. is preferably 1000 mPa s or more, more preferably 3000 mPa s or more, and even more preferably 5000 mPa s or more. Such a viscosity tends to improve the dispersibility of the inorganic filler (C) in the composition (X).

[0029] The liquid epoxy resin (a1) is not particularly limited as long as it is a common liquid epoxy resin, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, polyfunctional type epoxy resin, etc. The liquid epoxy resin (a1) may be used alone or in combination of two or more types.

[0030] The content of the liquid epoxy resin (a1) is preferably 20% by mass or more, more preferably 30% by mass or more, based on the total amount of the thermosetting resin component (A). On the other hand, the content of the liquid epoxy resin (a1) is preferably 60% by mass or less, more preferably 50% by mass or less, based on the total amount of the thermosetting resin component (A). When the content of the liquid epoxy resin (a1) is 20% by mass or more and 60% by mass or less, the flexibility of the resin layer 1 can be further ensured and powder falling can be further prevented.

[0031] It is preferable that the thermosetting resin component (A) further contains a solid epoxy resin (a2). The solid epoxy resin (a2) is solid at 25°C. When the thermosetting resin component (A) contains the solid epoxy resin (a2), the composition (X) can be easily formed into a film. In other words, the resin layer 1 can be easily produced.

[0032] The solid epoxy resin (a2) is not particularly limited as long as it is a general solid epoxy resin, and examples thereof include an epoxy resin having a naphthalene skeleton, a novolac epoxy resin, etc. The solid epoxy resin (a2) may be used alone or in combination of two or more.

[0033] The content of the solid epoxy resin (a2) is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total amount of the thermosetting resin component (A). On the other hand, the content of the solid epoxy resin (a2) is preferably 70% by mass or less, based on the total amount of the thermosetting resin component (A). When the content of the solid epoxy resin (a2) is 40% by mass or more and 70% by mass or less, the flexibility of the resin layer 1 can be further ensured and powder falling can be further prevented.

[0034] When the thermosetting resin component (A) contains a liquid epoxy resin (a1) and a solid epoxy resin (a2), the total content of the liquid epoxy resin (a1) and the solid epoxy resin (a2) is preferably 60% by mass or more, more preferably 90% by mass or more, based on the total amount of the thermosetting resin component (A). On the other hand, the total content of the liquid epoxy resin (a1) and the solid epoxy resin (a2) is preferably 99% by mass or less, more preferably 98% by mass or less, based on the total amount of the thermosetting resin component (A). When the total content of the liquid epoxy resin (a1) and the solid epoxy resin (a2) is 60% by mass or more and 99% by mass or less, the resin layer 1 is easily produced, the flexibility of the resin layer 1 is better ensured, and powder falling can be better prevented.

[0035] The thermosetting resin component (A) may contain a thermosetting resin other than the liquid epoxy resin (a1) and the solid epoxy resin (a2). There are no particular limitations on the thermosetting resin as long as it is a general thermosetting resin, and examples thereof include other epoxy resins, polyimide resins, phenolic resins, bismaleimide triazine resins, and thermosetting polyphenylene ether resins.

[0036] The thermosetting resin component (A) preferably contains a curing agent (a3) ​​and / or a curing accelerator (a4). When the thermosetting resin component (A) contains at least one of the curing agent (a3) ​​and the curing accelerator (a4), the film tackiness of the resin layer 1 can be suppressed.

[0037] The curing agent (a3) ​​is not particularly limited as long as it can react with the liquid epoxy resin (a1), and examples thereof include amine-based curing agents, difunctional or higher phenol-based curing agents, acid anhydride-based curing agents, dicyandiamide, and low-molecular-weight polyphenylene ether compounds.

[0038] The content of the curing agent (a3) ​​is preferably 3% by mass or more, more preferably 3.5% by mass or more, based on the total amount of the thermosetting resin component (A). On the other hand, the content of the curing agent (a3) ​​is preferably 4.5% by mass or less, more preferably 4.3% by mass or less, based on the total amount of the thermosetting resin component (A). When the content of the curing agent (a3) ​​is 3% by mass or more and 4.5% by mass or less, the film tackiness of the resin layer 1 can be further suppressed.

[0039] The curing accelerator (a4) is not particularly limited as long as it can accelerate the curing reaction of the liquid epoxy resin (a1). Examples of the curing accelerator (a4) include imidazole compounds, tertiary amine compounds, organic phosphine compounds, and metal soaps.

[0040] The curing accelerator (a4) preferably contains a metal soap. When the curing accelerator (a4) contains a metal soap, the storage stability of the composition (X) and the resin layer 1 is improved, and the resin layer 1 can easily maintain its excellent thick copper filling property. This is because, compared to other curing accelerators (a4), metal soaps have a smaller effect of accelerating the curing reaction of the liquid epoxy resin (a1) at room temperature, and even if a radical reaction starts, the curing reaction proceeds relatively slowly. Note that the thick copper filling property is synonymous with the "thick copper filling property" in the Examples section.

[0041] The content of the curing accelerator (a4) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more, based on the total amount of the thermosetting resin component (A). On the other hand, the content of the curing accelerator (a4) is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.7% by mass or less, based on the total amount of the thermosetting resin component (A). If the content of the curing accelerator (a4) is 0.1% by mass or more and 2.0% by mass or less, the film tackiness of the resin layer 1 can be further suppressed.

[0042] <Phosphorus-containing flame retardant (B)> The phosphorus-containing flame retardant (B) includes an aromatic condensed phosphate ester compound (b1). When the composition (X) contains such a phosphorus-containing flame retardant (B), the flame retardancy of a cured product of the composition (X) is enhanced.

[0043] The aromatic condensed phosphate ester compound (b1) has at least one phosphorus atom per molecule. The aromatic condensed phosphate ester compound (b1) refers to a phosphate ester compound having a chemical structure in which two or more phosphate ester units are linked by a divalent organic group having an aromatic ring, or a reaction product of phosphorus oxychloride with a divalent phenolic compound and phenol or an alkylphenol.

[0044] The acid value of the aromatic condensed phosphate ester compound (b1) is 0.25 KOHmg / g or less, which improves the insulating properties of the cured product of the composition (X).

[0045] The acid value is a value calculated from the amount of solution required to reach a neutralization point (inflection point) that appears within a pH range of 7 to 11. The acid value is measured in accordance with the potentiometric titration method of JIS K 0070, using a compound or a solution thereof as a sample and an alkaline solution for titration.

[0046] The acid value of the aromatic condensed phosphate ester compound (b1) is preferably 0.23 KOHmg / g or less, and more preferably 0.21 KOHmg / g or less, which further improves the insulating properties of the cured product of the composition (X).

[0047] The melting point of the aromatic condensed phosphate ester compound (b1) is 40° C. or less, which ensures flexibility of the resin layer 1 and prevents powder falling off.

[0048] The molecular weight of the aromatic condensed phosphate ester compound (b1) is preferably 600 or more. On the other hand, the molecular weight of the aromatic condensed phosphate ester compound (b1) is preferably 2000 or less, and more preferably 1000 or less.

[0049] The aromatic condensed phosphate ester compound (b1) preferably contains a bisphenol A condensed phosphate ester compound (b11). The bisphenol A condensed phosphate ester compound (b11) has a bisphenol A skeleton. Specific examples of the bisphenol A condensed phosphate ester compound (b11) include compounds represented by the following formula (1):

[0050]

[0051] In formula (1), each Ar is independently an aryl group. The aryl group is preferably a phenyl group. The hydrogen atoms on the phenyl group may be substituted with an alkyl group, a vinyl group, or the like. When the aromatic condensed phosphate ester compound (b1) contains a compound represented by formula (1), the flexibility of the resin layer 1 is further ensured and powder falling can be further prevented.

[0052] The aromatic condensed phosphate ester compound (b1) preferably does not have a boiling point. Here, "not having a boiling point" means that when the aromatic condensed phosphate ester compound (b1) is heated, the aromatic condensed phosphate ester compound (b1) undergoes thermal decomposition before reaching a temperature at which it changes state from liquid to gas. The absence of a boiling point in the aromatic condensed phosphate ester compound (b1) can prevent contamination of a press due to volatilization when the resin layer 1 is subjected to processing involving heating, such as heat pressing. Furthermore, the content of the aromatic condensed phosphate ester compound (b1) can be maintained in a cured product of the composition (X), preventing deterioration of the flame retardancy of the cured product of the composition (X).

[0053] Examples of the aromatic condensed phosphate ester compound (b1) include CR-741 manufactured by Daihachi Chemical Industry Co., Ltd.

[0054] The content of the phosphorus-containing flame retardant (B) is 10% by mass or more, preferably 11% by mass or more, and more preferably 12% by mass or more, based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B). When the content of the phosphorus-containing flame retardant (B) is 10% by mass or more, the flame retardancy of the cured product of the composition (X) is enhanced.

[0055] On the other hand, the content of the phosphorus-containing flame retardant (B) is 30% by mass or less, preferably 25% by mass or less, and more preferably 23% by mass or less, based on the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B). When the content of the phosphorus-containing flame retardant (B) is 30% by mass or less, the film tackiness of the resin layer 1 can be suppressed.

[0056] The content of the aromatic condensed phosphate ester compound (b1) is 10% by mass or more, and preferably 20% by mass or more, based on the total amount of the phosphorus-containing flame retardant (B). When the content of the aromatic condensed phosphate ester compound (b1) is 10% by mass or more, the flexibility of the resin layer 1 can be further ensured and powder falling can be prevented.

[0057] The phosphorus-containing flame retardant (B) may contain only one type of aromatic condensed acid phosphate ester compound (b1) or may contain two or more types in combination.

[0058] The phosphorus-containing flame retardant (B) may contain other flame retardants as long as the effects of this embodiment are not impaired. Specific examples of other flame retardants include monomeric phosphate esters (b2) and phosphazene-based flame retardants (b3). In particular, the phosphorus-containing flame retardant (B) preferably contains a phosphazene-based flame retardant (b3), which has a high phosphorus content and is likely to improve flame retardancy. The combined use of the aromatic condensed acid phosphate ester compound (b1) and the phosphazene-based flame retardant (b3) can ensure the flexibility of the resin layer 1, prevent powder fall-off, and further enhance the flame retardancy of the cured product of the composition (X).

[0059] <Inorganic Filler (C)> The inorganic filler (C) is not particularly limited as long as it is a common inorganic filler. When the composition (X) contains the inorganic filler (C), the linear expansion coefficient of the cured product of the composition (X) can be reduced, and the flame retardancy and heat resistance can be improved.

[0060] Specific examples of the inorganic filler (C) include silica, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, talc, clay, mica, and molybdenum compounds.

[0061] The inorganic filler (C) preferably contains an inorganic filler (c1) having a thermal weight change of 1% by mass or less. Here, the thermal weight change is synonymous with the thermal weight loss rate. Specifically, first, 20 mg of the inorganic filler (C) is weighed as a sample, and the weight of this sample at 20°C is measured. Next, this sample is heated to 200°C at 3°C / min. Thereafter, the weight of this sample at 200°C is measured. Then, the thermal weight change is calculated from the weights of the sample at 20°C and 200°C. If the calculated result is 1% by mass or less, it corresponds to the inorganic filler (c1), and if the calculated result is more than 1% by mass, it does not correspond to the inorganic filler (c1). Note that the thermal weight change can be measured using, for example, a "High-Performance Thermal Analyzer STA200" manufactured by Hitachi High-Tech Corporation.

[0062] Specific examples of the inorganic filler (c1) include silica, molybdenum oxide, and alumina. That is, the inorganic filler (C) preferably contains at least one compound selected from the group consisting of silica, molybdenum oxide, and alumina. This enhances the crack resistance of the cured product of the composition (X).

[0063] The content of the inorganic filler (c1) is preferably 25% by mass or more, more preferably 50% by mass or more, based on the total amount of the inorganic filler (C). The upper limit of the content of the inorganic filler (c1) is not particularly limited, but is, for example, 100% by mass. When the content of the inorganic filler (c1) is 25% by mass or more, the crack resistance of the cured product of the composition (X) is further improved.

[0064] The inorganic filler (C) preferably contains aluminum hydroxide, which enhances the flame retardancy of the cured product of the composition (X).

[0065] When the inorganic filler (C) contains silica and aluminum hydroxide, the silica content is preferably at least 2 times, more preferably at least 3 times, the aluminum hydroxide content, by mass. On the other hand, the silica content is preferably at most 10 times, more preferably at most 6 times, the aluminum hydroxide content, by mass. By making the silica content at least 2 times and not more than 10 times the aluminum hydroxide content, the cured product of the composition (X) can have both good crack resistance and good flame retardancy.

[0066] The content of the inorganic filler (C) is 200 parts by mass or more and 900 parts by mass or less per 100 parts by mass of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B) combined. This ensures flexibility of the resin layer 1 and prevents powder falling. Furthermore, the resin layer 1 also has improved copper filling properties.

[0067] The content of the inorganic filler (C) is preferably 300 parts by mass or more per 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B), which reduces the linear expansion coefficient of the cured product of the composition (X) and improves the heat resistance and flame resistance.

[0068] On the other hand, the content of the inorganic filler (C) is preferably 700 parts by mass or less, more preferably 500 parts by mass or less, per 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B). This ensures the flexibility of the resin layer 1 and prevents powder falling. Furthermore, the copper filling capacity is improved.

[0069] <Additives> Composition (X) may further contain additives other than the above components, as long as the effects of this embodiment are not impaired. The additives are not particularly limited, but examples thereof include coupling agents, antifoaming agents, heat stabilizers, antistatic agents, UV absorbers, dyes, pigments, lubricants, dispersants, etc.

[0070] <Resin Film Material> As shown in FIG. 1, the resin film material 10 according to this embodiment includes a carrier film 7 and a resin layer 1 that is overlaid on the carrier film and contains an uncured or semi-cured product of the composition (X).

[0071] The carrier film 7 is a flexible film such as a polyethylene terephthalate film. The surface of the carrier film 7 that overlaps the resin layer 1 is preferably treated to enhance releasability. An example of such a treatment is silicone coating.

[0072] The thickness of the carrier film 7 is not particularly limited, but is, for example, 10 μm or more and 150 μm or less.

[0073] Composition (X) is formed into a sheet on carrier film 7 by coating or the like, and then dried or semi-cured by heating. This produces resin layer 1 made of uncured or semi-cured composition (X), and a resin film material 10 including carrier film 7 and resin layer 1 is obtained. The heating temperature is, for example, 100°C or higher and 160°C or lower, and the heating time is, for example, 5 minutes or higher and 10 minutes or lower.

[0074] The thickness of the resin layer 1 is preferably 50 μm or more, more preferably 75 μm or more, and even more preferably 100 μm or more. If the thickness of the resin layer 1 is too thin, a large number of resin film materials 10 are required when laminating the resin layer 1 on the insulating layer 42 on which the thick conductor wiring 41 is formed, making handling inconvenient.

[0075] The thickness of the resin layer 1 is preferably 200 μm or less, more preferably 175 μm or less, and even more preferably 150 μm or less. If the thickness of the resin layer 1 is too thick, it becomes difficult to process it into the resin film material 10.

[0076] The overall thickness of the resin film material 10 (the total thickness of the resin layer 1 and the carrier film 7) is preferably 60 μm or more, more preferably 65 μm or more, and even more preferably 70 μm or more. If the overall thickness of the resin film material 10 is 60 μm or more, the carrier film 7 will be particularly likely to hold the resin layer 1. Furthermore, the resin layer 1 will be less likely to tear when the resin film material 10 is handled.

[0077] On the other hand, the total thickness of the resin film material 10 is preferably 550 μm or less, more preferably 450 μm or less, and even more preferably 400 μm or less. If the total thickness of the resin film material 10 is 550 μm or less, the resin layer 1 is particularly easily peeled from the carrier film 7. Furthermore, when the resin film material 10 is stored in a rolled state, cracks are less likely to occur in the resin layer 1.

[0078] <Printed Wiring Board> A printed wiring board 5 can be manufactured using the resin film material 10. The printed wiring board 5 includes conductor wiring 41 and an insulating layer 6 overlying the conductor wiring 41, and the insulating layer 6 includes a cured product of the composition (X). The printed wiring board 5 is manufactured, for example, by hot pressing a laminate 3 including a core material 4 having the conductor wiring 41 and a resin layer 1. A specific example of a method for manufacturing the printed wiring board 5 is described below.

[0079] First, there are prepared the resin film material 10, the prepreg 2, and the core material 4. The details of the resin film material 10 have already been described.

[0080] The prepreg 2 includes, for example, a substrate 8 and an uncured or semi-cured thermosetting resin composition (hereinafter also referred to as composition (Y)) impregnated into the substrate 8. The prepreg 2 is produced, for example, by impregnating the substrate 8 with composition (Y) and then heating the composition (Y) to dry or semi-cure it.

[0081] The substrate 8 is, for example, a woven fabric or a nonwoven fabric. The substrate 8 is made of, for example, glass fiber, inorganic fiber other than glass fiber, or organic fiber. The organic fiber includes, for example, at least one material selected from the group consisting of aramid fiber, polyparaphenylene benzobisoxazole (PBO) fiber, polybenzimidazole (PBI) fiber, polytetrafluoroethylene (PTFE) fiber, polyparaphenylene benzobisthiazole (PBZT) fiber, and wholly aromatic polyester fiber.

[0082] The composition (Y) contains a thermosetting resin and, if necessary, at least one component selected from the group consisting of a curing agent, a curing accelerator, a rubber component, an inorganic filler, and a flame retardant.

[0083] Examples of thermosetting resins include epoxy resins, polyimide resins, phenolic resins, and bismaleimide triazine resins.

[0084] The curing agent may include, for example, at least one component selected from the group consisting of diamine-based curing agents, difunctional or higher phenol-based curing agents, acid anhydride-based curing agents, dicyandiamide, and low-molecular-weight polyphenylene ether compounds.

[0085] The curing accelerator may include, for example, at least one component selected from the group consisting of imidazole compounds, tertiary amine compounds, organic phosphine compounds, and metal soaps.

[0086] The rubber component includes, for example, elastomer particles having a core-shell structure.

[0087] The inorganic filler includes, for example, at least one compound selected from the group consisting of silica, molybdenum compounds, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, talc, clay, and mica.

[0088] The flame retardant preferably includes a non-halogen flame retardant, such as a phosphorus-containing compound or a nitrogen-containing compound.

[0089] The core material 4 includes, for example, an insulating layer 42 and conductive wiring 41 overlapping the insulating layer 42. The insulating layer 42 is made of, for example, a resin having insulating properties. The conductive wiring 41 is made of a metal such as copper.

[0090] The thickness of the conductor wiring 41 is not particularly limited. In this embodiment, the resin layer 1 easily melts and fills the gaps between adjacent conductor wirings 41, so good thick copper filling can be achieved even if the conductor wiring 41 is thick. Therefore, the printed wiring board 5 according to this embodiment is easily applicable to, for example, industrial equipment and automotive board applications that require the flow of relatively large currents. The thickness of the conductor wiring 41 is not particularly limited, but is, for example, 200 μm or more. On the other hand, the thickness of the conductor wiring 41 is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. If the thickness of the conductor wiring 41 is 1000 μm or less, excellent thick copper filling can be achieved.

[0091] When manufacturing a printed wiring board 5, for example, as shown in FIG. 2A , a resin film material 10 is overlaid on a core material 4 so that the resin layer 1 and the conductor wiring 41 face each other. Next, as shown in FIG. 2B , the carrier film 7 is peeled off from the resin layer 1 while the resin layer 1 remains overlaid on the core material 4. Then, as shown in FIG. 3A , at least one prepreg 2 (two in this embodiment) is overlaid on the resin layer 1. That is, the core material 4, the resin layer 1, and at least one prepreg 2 are laminated in this order. This results in a laminate 3 including the prepreg 2, the resin layer 1, and the core material 4, as shown in FIG. 3A . Note that a metal foil such as copper foil may be further overlaid on the prepreg 2.

[0092] Next, the laminate 3 is hot-pressed. The hot-pressing conditions are appropriately set depending on the composition, size, etc. of the resin layer 1 and the prepreg 2, but for example, the heating temperature is 170°C or higher and 210°C or lower, the pressing pressure is 0.5 MPa or higher and 3.0 MPa or lower, and the time is 60 minutes or higher and 120 minutes or lower.

[0093] When the laminate 3 is heat-pressed as described above, the resin layer 1 and the prepreg 2 melt and then harden, producing an insulating layer 6 made of the hardened resin layer 1 and the prepreg 2. At this time, the substrate 8 contained in the prepreg 2 is not in direct contact with the conductor wiring 41. The resin layer 1, which does not contain the substrate 8, is in contact with the conductor wiring 41, and the resin layer 1 melts and flows, easily filling the gaps between adjacent conductor wirings 41.

[0094] In this manner, as shown in FIG. 3B , a printed wiring board 5 is obtained, which includes an insulating layer 42 derived from the core material 4, conductor wiring 41 derived from the core material 4, and an insulating layer 6 made from the resin layer 1 and the prepreg 2.

[0095] The configuration of the printed wiring board 5 made from the resin layer 1 is not limited to the above. For example, in the above description, the printed wiring board 5 includes the insulating layer 6 made from the resin layer 1 and the cured product of the prepreg 2, but the insulating layer 6 may be made only from the resin layer 1, that is, the printed wiring board 5 may include the insulating layer 6 made from the cured product of the resin layer 1. The printed wiring board 5 may include three or more insulating layers, and in this case, at least one of the insulating layers may include the cured product of the resin layer 1 (i.e., the cured product of the composition (X)).

[0096] [Aspects] As is clear from the above embodiment, the present disclosure includes the following aspects. In the following, reference numerals are given in parentheses only to clarify the correspondence with the embodiment.

[0097] A first aspect is a resin composition containing a thermosetting resin component (A), a phosphorus-containing flame retardant (B), and an inorganic filler (C). The thermosetting resin component (A) contains a liquid epoxy resin (a1) having a viscosity of 50,000 mPa or less at 25°C. The phosphorus-containing flame retardant (B) contains an aromatic condensed phosphate ester compound (b1) having a melting point of 40°C or less and an acid value of 0.25 KOHmg / g or less. The content of the phosphorus-containing flame retardant (B) is 10% by mass or more and 30% by mass or less, based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B). The content of the aromatic condensed phosphate ester compound (b1) is 10% by mass or more and 100% by mass or less, based on the total amount of the phosphorus-containing flame retardant (B). The content of the inorganic filler (C) is 200 parts by mass or more and 900 parts by mass or less relative to 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

[0098] According to this embodiment, the resin composition ensures flexibility of the resin layer (1) and prevents powder falling off, and improves the flame retardancy and insulating properties of the cured product.

[0099] A second aspect is the resin composition based on the first aspect. In the second aspect, the aromatic condensed phosphate ester compound (b1) includes a bisphenol A-type condensed phosphate ester compound (b11).

[0100] A third aspect is the resin composition according to the first or second aspect, wherein the content of the phosphorus-containing flame retardant (B) is 11% by mass or more and 25% by mass or less, based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

[0101] According to this embodiment, when the content of the phosphorus-containing flame retardant (B) is 11% by mass or more, the flame retardancy of the cured product of the resin composition is enhanced. When the content of the phosphorus-containing flame retardant (B) is 25% by mass or less, the film tackiness of the resin layer (1) can be suppressed.

[0102] A fourth aspect is a resin composition based on any one of the first to third aspects, wherein the thermosetting resin component (A) further comprises a solid epoxy resin (a2).

[0103] A fifth aspect is a resin composition based on any one of aspects 1 to 4. In the fifth aspect, the thermosetting resin component (A) includes a curing agent (a3) ​​and / or a curing accelerator (a4).

[0104] A sixth aspect is a resin composition based on any one of the first to fifth aspects, wherein the inorganic filler (C) includes at least one compound selected from the group consisting of silica, molybdenum oxide, and alumina.

[0105] A seventh aspect is a resin composition based on any one of aspects 1 to 6. In the seventh aspect, the total content of the liquid epoxy resin (a1) and the solid epoxy resin (a2) is 60% by mass or more and 99% by mass or less, based on the total amount of the thermosetting resin component (A).

[0106] An eighth aspect is a resin composition based on any one of aspects 1 to 7. In the eighth aspect, the aromatic condensed phosphate ester compound (b1) has a molecular weight of 600 or more.

[0107] A ninth aspect is a resin composition based on any one of aspects 1 to 8. In the ninth aspect, the phosphorus-containing flame retardant (B) further contains a phosphazene-based flame retardant (b3).

[0108] A tenth aspect is a resin film material (10) comprising a carrier film (7) and a resin layer (1) that is overlaid on the carrier film (7) and contains an uncured or semi-cured resin composition based on any one of the first to ninth aspects.

[0109] An eleventh aspect is a resin film material (10) based on the tenth aspect. In the eleventh aspect, the thickness of the resin layer (1) is 50 μm or more and 200 μm or less.

[0110] A twelfth aspect is a printed wiring board (5) comprising a conductor wiring (41) and an insulating layer (6) overlapping the conductor wiring (41). The insulating layer (6) contains a cured product of a resin composition based on any one of the first to ninth aspects.

[0111] A thirteenth aspect is a printed wiring board (5) based on the twelfth aspect. In the thirteenth aspect, the thickness of the conductor wiring (41) is 200 μm or more.

[0112] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to the following examples.

[0113] (1) Preparation of Composition Composition (X) was prepared by mixing the components shown in Tables 1 and 2. Details of each component are as follows.

[0114] <Thermosetting resin component (A)> Liquid epoxy resin (a1), manufactured by DIC Corporation, product number: Epiclon 830-S, viscosity at 25°C: 25,000 mPa·s.

[0115] Solid epoxy resin (a2), manufactured by Printec Co., Ltd., product number: VG3101; hardener (a3), DICY (dicyandiamide); hardening accelerator (a4), manufactured by DIC Corporation, product number: Zn-OCTOATE 22%.

[0116] <Phosphorus-containing flame retardants (B)> Aromatic condensed phosphate ester compound (b1), manufactured by Daihachi Chemical Industry Co., Ltd., product number: CR-741, melting point: 4 to 5°C, acid value: 0.20 KOHmg / g, boiling point: none Aromatic condensed phosphate ester compound 1, manufactured by Daihachi Chemical Industry Co., Ltd., product number: CR-733S, melting point: -13°C, acid value: 0.5 KOHmg / g, boiling point: none Aromatic condensed phosphate ester compound 2, manufactured by Daihachi Chemical Industry Co., Ltd., product number: PX-200, melting point: 90°C, acid value: 0.5 KOHmg / g, boiling point: none Monomeric phosphate ester (b2), manufactured by Daihachi Chemical Industry Co., Ltd., product number: TMP, melting point: -70°C, acid value: 0.2 KOHmg / g, boiling point: 180 to 195°C Phosphazene flame retardant (b3): ​​manufactured by Mitsui Chemicals Fine Chemicals Co., Ltd., product number: FP-100, melting point: 90°C, boiling point: 400°C.

[0117] <Inorganic Filler (C)> Silica (c1): manufactured by Admatechs, product number: SC-2500GNO, thermal weight change: 1% by mass or less Aluminum hydroxide: manufactured by Kawai Lime Industry, product number: ALH-F.

[0118] (2) Preparation of Resin Film Material A silicone-coated film (product number: SP-PET, thickness: 75 μm) manufactured by Mitsui Chemicals Tohcello Co., Ltd. was used as a carrier film. The resin composition was applied to this carrier film and then heated at 85°C for 1.5 minutes, then at 120°C for 1 minute, and then at 160°C for 1 minute. This produced a resin layer with a thickness of 100 μm and a volatile content of 0.45% by mass. This resulted in a resin film material comprising a carrier film and a resin layer supported thereon.

[0119] (3) Fabrication of a Printed Wiring Board A core material was prepared, which had an insulating layer with a thickness of 200 μm and a conductor wiring with a thickness of 400 μm overlaid thereon. The conductor wiring had a line width of 800 μm, a space width of 1000 μm, and a copper residual ratio of 50%.

[0120] Furthermore, as a prepreg, a product name: R-1551(S) (resin component: epoxy resin, substrate: glass cloth (glass cloth style 2116)) manufactured by Panasonic Corporation was prepared.

[0121] A laminate was obtained by stacking one resin layer of the resin film material on the conductor wiring of the core material, and then stacking two prepregs on top of that. This laminate was then heat-pressed. The heating temperature during the heat press was first increased from 30°C to 200°C at a rate of 2°C / min, and then held at 200°C for 120 minutes. The pressing pressure was 0.5 MPa for the first 60 minutes and 2.0 MPa for the next 145 minutes. This resulted in a printed wiring board having an insulating layer derived from the core material, conductor wiring, and an insulating layer made from the resin layer and prepreg.

[0122] (4) Evaluation (4-1) Flame Retardancy The flame retardancy (flame resistance) of the insulating layer made of the resin layer and the prepreg was evaluated by a combustion test in accordance with UL94.

[0123] (4-2) R-10 Bending Evaluation The resin film material was wrapped around a cylinder with a diameter of 10 mm. As a result, if no cracks occurred in the resin layer of the resin film material, it was rated as "A", and if cracks occurred, it was rated as "B".

[0124] (4-3) Evaluation of Powder Falling off with Cutter The resin film material was cut with a cutter knife. If the area around the cut surface crumbled and powder fell off, it was rated as "B", and if the area around the cut surface did not crumble and powder fall off was not observed, it was rated as "A".

[0125] (4-4) Voltage Withstand Characteristics Copper foil (manufacturer: NAN YA PLASTICS, copper foil type: NPHE, thickness: 35 μm) was layered on both sides of a resin layer (thickness: 100 μm) of a resin film material and hot-molded to obtain a sample for evaluating voltage withstand characteristics. In this sample, the resin layer was converted into an insulating layer, and copper foil was bonded to both sides of the insulating layer. A voltage of 10 kV was applied to the copper foil on both sides of the insulating layer using a "YST-243TP-100" manufactured by Yamayo Testing Instruments Co., Ltd., to confirm the voltage withstand characteristics of the insulating layer. As a result, samples that had sufficient insulating properties and did not conduct electricity were rated "A," and samples that conducted electricity were rated "B."

[0126] (4-5) Thick copper filling The cross section of the printed wiring board was observed to check for the presence or absence of voids in the insulating layer made of the resin layer and the prepreg. As a result, when no voids were observed, it was rated as "A", and when voids were observed, it was rated as "B".

[0127] (4-6) Film tackiness The resin film material was peeled off from the carrier film support, and the surface of the carrier film after peeling was checked. When residues of the resin layer were found on the carrier film, it was rated as "B," and when residues of the resin layer were not found on the carrier film, it was rated as "A."

[0128]

[0129]

[0130] The resin composition of Comparative Example 1 had an excessively large content of inorganic filler (C), which is thought to have deteriorated the R-10 bending evaluation, cutter powder shedding evaluation, and thick copper filling ability.

[0131] The resin composition of Comparative Example 2 uses only a phosphazene-based flame retardant (b3) having a melting point of more than 40°C as the phosphorus-containing flame retardant (B), which is thought to have deteriorated the R-10 bending evaluation and cutter powder fall evaluation.

[0132] The resin composition of Comparative Example 3 had an excessively small content of aromatic condensed phosphate ester compound (b1), which is thought to have resulted in poor R-10 bending evaluation and cutter powder shedding evaluation.

[0133] The resin composition of Comparative Example 4 has a low content of the phosphorus-containing flame retardant (B), and therefore has poor flame retardancy.

[0134] In the resin composition of Comparative Example 5, it is believed that part of the monomeric phosphate ester (b2) evaporates during heat molding, resulting in a lower proportion of flame retardant in the cured product, resulting in a deterioration in flame retardancy.

[0135] The resin composition of Comparative Example 6 used a large amount of aromatic condensed phosphate ester compound 1, which has a relatively high acid value, as the phosphorus-containing flame retardant (B), and this is thought to have caused the deterioration of the withstand voltage characteristics.

[0136] The resin composition of Comparative Example 7 uses only aromatic condensed phosphate ester compound 2 and phosphazene flame retardant (b3) having a melting point of over 40°C as the phosphorus-containing flame retardant (B), which is thought to have deteriorated the R-10 bending evaluation and cutter dust removal evaluation. In addition, the aromatic condensed phosphate ester compound 2 has a relatively high acid value, which is thought to have deteriorated the withstand voltage characteristics.

[0137] REFERENCE SIGNS LIST 1 resin layer 41 conductor wiring 5 printed wiring board 6 insulating layer 7 carrier film 10 resin film material

Claims

1. A flame retardant composition comprising a thermosetting resin component (A), a phosphorus-containing flame retardant (B), and an inorganic filler (C), wherein the thermosetting resin component (A) comprises a liquid epoxy resin (a1) having a viscosity of 50,000 mPa or less at 25°C, the phosphorus-containing flame retardant (B) comprises an aromatic condensed phosphate ester compound (b1) having a melting point of 40°C or less and an acid value of 0.25 KOHmg / g or less, the content of the phosphorus-containing flame retardant (B) being 10% by mass or more and 30% by mass or less based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B), the content of the aromatic condensed phosphate ester compound (b1) being 10% by mass or more and 100% by mass or less based on the total amount of the phosphorus-containing flame retardant (B), A resin composition, wherein the content of the inorganic filler (C) is 200 parts by mass or more and 900 parts by mass or less per 100 parts by mass of the total of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

2. The resin composition according to claim 1, wherein the aromatic condensed phosphate ester compound (b1) comprises a bisphenol A-type condensed phosphate ester compound (b11).

3. The resin composition according to claim 1, wherein the content of the phosphorus-containing flame retardant (B) is 11 mass% or more and 25 mass% or less based on the total amount of the thermosetting resin component (A) and the phosphorus-containing flame retardant (B).

4. The resin composition according to claim 1, wherein the thermosetting resin component (A) further comprises a solid epoxy resin (a2).

5. The resin composition according to claim 1, wherein the thermosetting resin component (A) contains a curing agent (a3) ​​and / or a curing accelerator (a4).

6. The resin composition according to claim 1, wherein the inorganic filler (C) contains at least one compound selected from the group consisting of silica, molybdenum oxide, and alumina.

7. The resin composition according to claim 4, wherein the total content of the liquid epoxy resin (a1) and the solid epoxy resin (a2) is 60 mass % or more and 99 mass % or less based on the total amount of the thermosetting resin component (A).

8. The resin composition according to claim 1, wherein the aromatic condensed phosphate ester compound (b1) has a molecular weight of 600 or more.

9. The resin composition according to claim 1, wherein the phosphorus-containing flame retardant (B) further comprises a phosphazene-based flame retardant (b3).

10. A resin film material comprising: a carrier film; and a resin layer overlying the carrier film and containing an uncured or semi-cured product of the resin composition according to any one of claims 1 to 9.

11. The resin film material according to claim 10, wherein the resin layer has a thickness of 50 μm or more and 200 μm or less.

12. A printed wiring board comprising a conductor wiring and an insulating layer overlapping the conductor wiring, the insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 9.

13. The printed wiring board according to claim 12, wherein the thickness of the conductor wiring is 200 μm or more.

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