Curable resin composition, and insulating film and printed circuit

Abstract

Provided is a curable resin composition comprising: a maleimide compound comprising a diphenylmethane structure; a free radical polymerizable resin; a high molecular weight resin containing a conjugated diene structure; and an inorganic filler, in which the inorganic filler is contained in an amount of 200 parts by mass or more and 400 parts by mass or less based on a total solid content of 100 parts by mass of the maleimide compound including the diphenylmethane structure, the radical polymerizable resin, and the high molecular weight resin including the conjugated diene structure, and thus, the inorganic filler is not less than 100 parts by mass. A low coefficient of thermal expansion, an ultra-low dissipation factor and improved brittleness can be ensured.

Description

TECHNICAL FIELD

[0001] The present specification relates to a curable resin composition and an insulating film and a printed circuit board including the same.

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0135574, filed on October 12, 2023, and Korean Patent Application No. 10-2024-0134157, filed on October 2, 2024, in the Korean Intellectual Property Office, the contents of all of which are incorporated herein by reference in their entirety. BACKGROUND

[0003] As a support for electronic components, a printed circuit board (PCB) means a board in which electronic components are fixed to the surface of a printed wiring board and the components are connected with copper wiring to form an electronic circuit.

[0004] In general, a printed circuit board is based on forming a plurality of layers through an insulating connection between copper wiring. In order to improve the reliability of the board, methods of improving the adhesion strength between the insulating layer and the copper foil layer have been proposed, such as a method of including a component having a high bonding strength with Cu in the insulating layer or a method of forming a surface roughness on the surface of the insulating layer to increase the surface area of the interface.

[0005] As a method for manufacturing a multi-layer printed circuit board, such a method has been known in which a prepreg sheet on which a copper foil circuit is formed is stacked on an inner layer circuit board and interlayer connection is made through a via, but the method requires large-scale equipment, is high in cost and time-consuming, and has a problem in that it is difficult to form a fine pattern.

[0006] As a method of solving the above problems, a method of manufacturing a multi-layer printed circuit board in combination with a build-up method has recently been proposed. The build-up method is a technology for alternately stacking a conductor layer of a circuit board and an organic insulating layer (or an insulating film), and includes the steps of complete curing, drilling, roughening treatment, electroless plating, electroplating, post-curing, and forming an outer layer circuit after vacuum lamination of the insulating film.

[0007] Although an epoxy resin and a phenol-based curing agent have been used as a curable resin composition for an insulating film in the related art, an epoxy resin and a cyanate-based curing agent or an active ester-based curing agent are used as a curable resin composition for an insulating film when a low dissipation factor is required in order to transmit a signal at a high speed.

[0008] Recently, as the demand for a low dissipation factor becomes more urgent, there is a tendency to add a maleimide compound to a curable resin composition for an insulating film having high heat resistance and low dielectric properties.

[0009] However, another material epoxy resin used in the curable resin composition for an insulating film exhibits a dissipation factor exceeding 0.005 based on 10 GHz, thus having a limitation in achieving an ultra-low dissipation factor.

[0010] Further, since the maleimide compound, which is a key substance for achieving a low dissipation factor, has a characteristic of having a high softening point, the cured product of the maleimide-containing curable resin composition tends to be brittle. In order to solve these problems, the addition of a thermoplastic resin such as a phenoxy resin has been attempted, but there is a disadvantage of causing thermal distortion during a process due to a high linear thermal expansion coefficient.

[0011] Therefore, further research on the curable resin composition is required. SUMMARY

[0012] TECHNICAL PROBLEM

[0013] The present application has been made in an effort to provide a curable resin composition, and an insulating film and a printed circuit board including the same.

[0014] TECHNICAL SOLUTION

[0015] The present inventors have found that the combination of a maleimide compound including a diphenylmethane structure, a radically polymerizable resin, a high molecular weight resin including a conjugated diene structure, and an inorganic filler having a specific content range in the curable resin composition solves the problems of the existing curable resin composition, and can exhibit a low linear thermal expansion coefficient and improved brittleness as well as an ultra-low dissipation factor. The curable resin composition according to the present application is characterized by not including an epoxy resin, while being capable of self-initiation, and can achieve a low dissipation factor so as to transmit a signal at a high speed.

[0016] Therefore, based on the above characteristics, exemplary embodiments of the present application are as follows.

[0017] One exemplary embodiment of the present application provides a curable resin composition including: a maleimide compound including a diphenylmethane structure; a radically polymerizable resin; a high molecular weight resin including a conjugated diene structure; and an inorganic filler, wherein the inorganic filler is included in an amount of 200 parts by mass or more and 400 parts by mass or less, based on 100 parts by mass of the total solid content of the maleimide compound including a diphenylmethane structure, the radically polymerizable resin, and the high molecular weight resin including a conjugated diene structure.

[0018] Another exemplary embodiment provides an insulating film including the above-described curable resin composition or a cured product thereof.

[0019] Still another exemplary embodiment provides a printed circuit board including the above-described insulating film.

[0020] Advantages

[0021] The curable resin composition according to the present specification has a low linear thermal expansion coefficient, and thus can prevent cracks in future reliability tests of an insulating film.

[0022] The curable resin composition according to the present specification has a high peel strength in future insulating films, and thus can provide excellent copper foil adhesion.

[0023] In particular, the curable resin composition according to the present specification can provide the advantage of preventing a decrease in peel strength under the condition of a high content of inorganic fillers. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 An example of the use of the curable resin composition according to one example embodiment of the present specification is schematically shown. DETAILED DESCRIPTION

[0025] Hereinafter, the present specification will be described in more detail.

[0026] In the present specification, when one member is provided "on" another member, this includes not only a case in which one member is in contact with another member, but also a case in which yet another member is present between the two members.

[0027] In the present specification, when one portion "includes" a constituent element, this does not mean excluding another constituent element unless specifically described otherwise, but means that another constituent element can also be included.

[0028] In the present specification, "polymer" means a compound composed of the repetition of a repeating unit (basic unit). The polymer can be referred to as a macromolecule (polymer) or a compound composed of a macromolecule, and the polymer can have one or more repeating units.

[0029] <Curable resin composition>

[0030] Hereinafter, the curable resin composition according to one example embodiment of the present specification will be described.

[0031] The curable resin composition according to one example embodiment of the present specification includes a maleimide compound including a diphenylmethane structure, a radically polymerizable resin, a high molecular weight resin including a conjugated diene structure, and an inorganic filler, wherein based on 100 parts by mass of the total solid content of the maleimide compound including a diphenylmethane structure, the radically polymerizable resin, and the high molecular weight resin including a conjugated diene structure, the inorganic filler is included in an amount of 200 parts by mass or more and 400 parts by mass or less.

[0032] In the present specification, the "solid content" can also be expressed as "non-volatile content", and means measured by a method known in the art.

[0033] In one exemplary embodiment of the present application, based on 100 parts by mass of the total solid content of the maleimide compound including a diphenylmethane structure, the radically polymerizable resin, and the high molecular weight resin including a conjugated diene structure, the content of the inorganic filler can be 200 parts by mass or more, and 400 parts by mass or less, 390 parts by mass or less, 380 parts by mass or less, 370 parts by mass or less, 350 parts by mass or less, 340 parts by mass or less, 330 parts by mass or less, 320 parts by mass or less, 310 parts by mass or less, or 300 parts by mass or less.

[0034] The curable resin composition includes four components, and wherein, when the content of the inorganic filler is within the above range, a low coefficient of linear thermal expansion of 25 ppm / °C or less and an ultra-low dissipation factor of 0.003 or less can be achieved, and improvement in brittleness can be achieved.

[0035] In particular, when the content of the inorganic filler is less than 200 parts by mass, based on 100 parts by mass of the total solid content of the maleimide compound including a diphenylmethane structure, the radically polymerizable resin, and the high molecular weight resin including a conjugated diene structure, the coefficient of thermal expansion can be higher than the desired range, and when the content exceeds 400 parts by mass, the brittleness can increase.

[0036] Referring to Figure 1 , one example of the use of the curable resin composition according to one exemplary embodiment of the present application is shown. Specifically, Figure 1 a multilayer printed circuit board incorporating a build-up method is shown, in which the insulating layer (or insulating film) includes the curable resin composition according to one exemplary embodiment of the present application.

[0037] According to one exemplary embodiment of the present application, the maleimide compound including a diphenylmethane structure can be represented by the following Chemical Formula 1.

[0038] [Chemical Formula 1]

[0039]

[0040] In Chemical Formula 1,

[0041] R1 to R4 are the same as or different from each other, and each is independently hydrogen; an alkyl group; an aryl group; a heteroaryl group; or a substituent represented by the following Chemical Formula 2, and at least one of R1 to R4 is the substituent represented by the following Chemical Formula 2,

[0042] a and b are the same as or different from each other, and each independently an integer of 0 to 5, and when a and b are each an integer of 2 or more, the substituents in the parentheses are the same as or different from each other,

[0043] [Chemical Formula 2]

[0044]

[0045] In Chemical Formula 2,

[0046] means a bond to Chemical Formula 1,

[0047] L1is a direct bond; alkylene; arylene; or heteroarylene,

[0048] R5and R6are the same as or different from each other, and each independently hydrogen; alkyl; aryl; or heteroaryl, and

[0049] m is an integer of 0 to 4.

[0050] Chemical Formula 1 is a diphenylmethane structure, and Chemical Formula 2 means a maleimide compound.

[0051] When a maleimide compound containing a diphenylmethane structure as described above is used in an insulating film, an ultra-low dissipation factor and improved brittleness can be obtained.

[0052] In one exemplary embodiment of the present application, the content of a maleimide compound containing a diphenylmethane structure can be 1% by mass or more, 2% by mass or more, or 3% by mass or more, and 20% by mass or less, 19% by mass or less, or 18% by mass or less, based on the solid content of 100% by mass of the curable resin composition.

[0053] When the content as described above is satisfied, brittleness can be further improved, and an ultra-low dissipation factor can be obtained.

[0054] In one exemplary embodiment of the present application, a maleimide containing a diphenylmethane structure is not particularly limited as long as it satisfies the structure of Chemical Formula 1, but examples thereof can include BMI-5100, BMI-2300 (Daiwakasei Industry Co., Ltd.), and the like, and if necessary, one type can be used alone or two or more types can be used in combination.

[0055] According to one exemplary embodiment of the present specification, the radically polymerizable resin includes an unsaturated group, and the unsaturated group can be selected from a (meth)acrylate group, a (meth)acrylamide group, a salt of an organic acid, a vinyl ether group, an allyl ether group, a vinyl ester group, a styryl group, a vinyl group, and an allyl ester group, but is not particularly limited as long as it does not deviate from the spirit of the present invention and is well known in the art.

[0056] Examples of the radically polymerizable resin can include OPE-2St series (Mitsubishi Gas Chemical Company, Inc.), etc., and one type can be used alone or two or more types can be used in combination, if necessary.

[0057] In one exemplary embodiment of the present invention, the content of the radically polymerizable resin can be 10% by mass or greater, 11% by mass or greater, or 12% by mass or greater, and 30% by mass or less, 29% by mass or less, or 28% by mass or less, based on the solid content of 100% by mass of the curable resin composition.

[0058] When the content as described above is satisfied, polymerization is facilitated, and other properties required for the curable resin composition can be additionally obtained.

[0059] According to one exemplary embodiment of the present specification, the high molecular weight resin including a conjugated diene structure can include a unit represented by the following Chemical Formula 3 in at least one of a main chain and a side chain.

[0060] [Chemical Formula 3]

[0061]

[0062] In Chemical Formula 3,

[0063] * is a position connected to another unit,

[0064] R7 to R12 are the same as or different from each other, and each is independently hydrogen; an alkyl group; an aryl group; or a heteroaryl group, and

[0065] n is 90 or greater and 4000 or less.

[0066] When the high molecular weight resin having the structure as described above is used in the insulating film, a cured product having improved brittleness and excellent dielectric properties can be obtained.

[0067] In one exemplary embodiment of the present application, the content of the high molecular weight resin including a conjugated diene structure can be 1 mass% or more, 2 mass% or more, or 3 mass% or more, and 20 mass% or less, 19 mass% or less, or 18 mass% or less, based on the solid content of the 100 mass% of the curable resin composition.

[0068] When the content as described above is satisfied, a cured product having improved brittleness and excellent dielectric properties can be obtained.

[0069] According to one exemplary embodiment of the present specification, the high molecular weight resin including a conjugated diene structure includes a polybutadiene resin, a styrene-butadiene resin, a styrene-butadiene-styrene resin, a styrene-ethylene-butylene-styrene resin, a styrene-butadiene-butylene-styrene resin, and the like, but is not limited thereto, as long as it does not depart from the scope of the present application.

[0070] According to one exemplary embodiment of the present specification, the weight average molecular weight (MW) of the high molecular weight resin including a conjugated diene structure can be 4,000 g / mol or more and 200,000 g / mol or less.

[0071] When the weight average molecular weight (MW) of the high molecular weight resin including a conjugated diene structure is less than 4,000 g / mol, it is difficult to handle the resin due to low viscosity and brittleness tends to deteriorate, and when the weight average molecular weight (MW) exceeds 200,000 g / mol, it can be difficult to perform a process of producing a film due to high viscosity.

[0072] In the present specification, the weight average molecular weight can be measured by a gel permeation chromatography (GPC) method (polystyrene equivalent).

[0073] According to one exemplary embodiment of the present specification, the average particle diameter of the inorganic filler can be 1.0 μm or less, preferably 0.7 μm or less, more preferably 0.5 μm or less, and 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more.

[0074] According to the exemplary embodiment, when the average particle diameter of the inorganic filler exceeds 1.0 μm, the surface roughness becomes large, such that an undesirable signal loss due to noise and precipitation occurs, which can result in poor uniformity, and when the average particle diameter of the inorganic filler is less than 0.1 μm, the minimum melt viscosity is excessively high, exceeding 20,000 cP in the temperature range of 70°C to 150°C, such that the processability can be deteriorated due to reduced flowability.

[0075] According to one exemplary embodiment of the present specification, the inorganic filler can be surface-treated with a surface treatment agent such as a coupling agent.

[0076] According to one exemplary embodiment of the present specification, the inorganic filler can be silica, silicate, barium sulfate, alumina, etc., but is not limited thereto.

[0077] In the present specification, the silica can be, for example, spherical silica, fused silica, hollow silica, crystalline silica, amorphous silica, etc., but is not limited thereto, and is commercially available as SOC1, SOC2 (Admatechs), etc.

[0078] According to one exemplary embodiment of the present specification, the curable resin composition can further include at least one of a thermosetting resin and a thermoplastic resin.

[0079] In the present specification, the thermosetting resin is a substance that is cured by applying heat and then has a shape that remains unchanged upon re-heating, and is not particularly limited to those well known in the art. If necessary, one type of thermosetting resin can be used alone, or two or more types can be used in combination, and the content can be appropriately changed, as long as it does not depart from the scope of the present invention.

[0080] In the present specification, the thermoplastic resin is a substance that is cured by applying heat and then has a shape that changes upon re-heating, and is not particularly limited to those well known in the art. If necessary, one type of thermoplastic resin can be used alone, or two or more types can be used in combination, and the content can be appropriately changed, as long as it does not depart from the scope of the present invention.

[0081] The curable resin composition according to one exemplary embodiment of the present invention further includes an additive and a solvent, and the additive can be selected from a leveling agent, a wetting agent, an antistatic agent, a flame retardant, a crosslinking agent, a curing accelerator, a curing agent, and a polymerization initiator.

[0082] In the present specification, the leveling agent is a substance that controls flowability when the curable resin composition is used in the future to prevent defects such as pits from occurring when applied to a surface in the future, and examples of the leveling agent well known in the art include BYK 350, BYK 354, BYK 356, BYK 359, BYK 399, etc., but are not particularly limited thereto. In some cases, one type of leveling agent can be used alone, or two or more thereof can be used in a mixture, and the content can be appropriately changed, as long as it does not depart from the scope of the present invention.

[0083] In the present specification, a wetting agent is a substance that accelerates wetting and aids in the aggregation of inorganic fillers, and is not particularly limited to those known in the art. If necessary, one type of wetting agent can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application.

[0084] In the present specification, an antistatic agent is a substance that imparts an antistatic effect, and is not particularly limited to those known in the art. If necessary, one type of antistatic agent can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application.

[0085] In the present specification, a flame retardant is a substance that reduces flammability or prevents combustion, and is not limited to those known in the art. If necessary, one type of flame retardant can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application.

[0086] In the present specification, a crosslinking agent is a substance that forms crosslinking bonds between polymers, and examples of crosslinking agents known in the art include TAIC, DAIC (allyl-based), ALP-d (benzoxazine-based), and the like, but are not particularly limited thereto. If necessary, one type of crosslinking agent can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application.

[0087] In the present specification, a curing accelerator is a substance that shortens the curing time, and is classified into phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, and the like known in the art, examples of the phosphorus-based curing accelerators include triphenylphosphine and the like, examples of the amine-based curing accelerators include triethylamine, tributylamine, and the like, and examples of the imidazole-based curing accelerators include 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, and the like, but are not particularly limited thereto. If necessary, one type of curing accelerator can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application.

[0088] In the present specification, a curing agent is a substance that is added to a curable resin to assist a curing reaction, and is classified into active ester-based curing agents, phenol-based curing agents, cyanate-based curing agents, and the like known in the art, but is not particularly limited thereto. If necessary, one type of curing agent can be used alone, or two or more types can be used in combination, and the content can be appropriately changed, so long as it does not depart from the scope of the present application. ​

[0089] In the present specification, a polymerization initiator is a substance that generates a radical or (cation) ion by a specific stimulus to initiate polymerization, and examples of the polymerization initiator known in the art include dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, and the like, but are not particularly limited thereto. If necessary, one type of polymerization initiator can be used alone, or two or more types thereof can be used in combination, and the content can be appropriately changed, provided that it does not depart from the scope of the present application.

[0090] According to one exemplary embodiment of the present specification, a solvent can be applied without any particular limitation, as long as it is known in the art to which the present application pertains to be capable of forming a curable resin composition. As one non-limiting example, the solvent can be one or more compounds selected from the group consisting of esters, ethers, ketones, aromatic hydrocarbons, and sulfoxides.

[0091] The ester solvent can be ethyl acetate, n-butyl acetate, isobutyl acetate, pentyl formate, isoamyl acetate, isobutyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate, butyl butyrate, methyl lactate, ethyl lactate, γ-butyrolactone, ε-caprolactone, δ-valerolactone, alkyl oxyacetic acid ester (e.g., methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate (e.g., methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, etc.)), alkyl 3-oxypropionate (e.g., methyl 3-oxypropionate, ethyl 3-oxypropionate, etc. (e.g., methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, etc.)), alkyl 2-oxypropionate (e.g., methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, etc. (e.g., methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate)), methyl 2-oxo-2-methylpropionate and ethyl 2-oxo-2-methylpropionate (e.g., methyl 2-methoxy-2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, etc.), methyl pyruvate, ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutyrate, ethyl 2-oxobutyrate, etc.

[0092] The ether solvent can be diglyme, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc.

[0093] The ketone solvent can be methyl ethyl ketone (MEK), cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, N-methyl-2-pyrrolidone, etc.

[0094] The aromatic hydrocarbon solvent can be toluene, xylene, anisole, limonene, or the like.

[0095] The sulfoxide solvent can be dimethyl sulfoxide or the like.

[0096] According to one example embodiment of the present specification, the curable resin composition further includes an additive, and the additive can be selected from the group consisting of a leveling agent, a wetting agent, an antistatic agent, and an antioxidant.

[0097] <insulating film>

[0098] Hereinafter, an insulating film including a curable resin composition according to one example embodiment of the present specification or a cured product thereof will be described.

[0099] In the present specification, the cured product can be obtained by thermal curing.

[0100] In the present specification, the thermal curing can be performed under conditions well known in the art and by heating devices well known in the art, and for example, can be performed by curing and drying the cured product at 100°C or higher for a predetermined time.

[0101] The thickness of the insulating film according to one example embodiment of the present specification can be 5 μm or more, 10 μm or more, or 15 μm or more, and 40 μm or less, 35 μm or less, or 30 μm or less.

[0102] The linear thermal expansion coefficient of the insulating film according to one example embodiment of the present specification, measured according to ASTM D696, can be 25 ppm / °C or less.

[0103] The linear thermal expansion coefficient value of the insulating film according to one example embodiment of the present specification, measured according to ASTM D696, can be 24 ppm / °C or less, or 22 ppm / °C or less, and 0 ppm / °C or more.

[0104] The insulating film having a linear thermal expansion coefficient in the range as described above has little difference in expansion rate from a future support, so that deformation such as peeling or cracking does not occur.

[0105] The dielectric constant (Dk) of the insulating film according to one example embodiment of the present specification, measured according to ASTM D2520 at 10 GHz, can be 0 or more and 4.0 or less.

[0106] The dielectric constant of the insulating film according to one example embodiment of the present specification, measured at 10 GHz according to ASTM D2520, can be 0.1 or greater, 0.5 or greater, or 1.0 or greater, and 3.9 or less, 3.7 or less, or 3.5 or less.

[0107] The insulating film having the dielectric constant as described above can increase the signal transmission speed in the future.

[0108] The dissipation factor (DF) of the insulating film according to one example embodiment of the present specification, measured at 10 GHz according to ASTM D2520, can be 0.001 or greater and 0.004 or less.

[0109] The dissipation factor of the insulating film according to one example embodiment of the present specification, measured at 10 GHz according to ASTM D2520, can be 0.0011 or greater, 0.0012 or greater, or 0.0013 or greater, and 0.0039 or less, 0.0038 or less, or 0.0037 or less.

[0110] The insulating film having the dissipation factor as described above can minimize the loss of the transmission signal in the future.

[0111] Since the curable resin composition described above is used as it is or the cured product thereof is used for the insulating film, the content regarding the curable resin composition can be applied.

[0112] <Printed circuit board>

[0113] Hereinafter, a printed circuit board according to one example embodiment of the present disclosure will be described.

[0114] Since the printed circuit board includes the insulating film in which the curable resin composition described above is used as it is or the cured product thereof is used, the content regarding the curable resin composition described above can be applied.

[0115] Inventive embodiments

[0116] Hereinafter, the present specification will be described in detail with reference to examples for specifically describing the present specification. However, the embodiments according to the present specification can be modified in various forms, and should not be interpreted as the scope of the present specification being limited to the following examples. The embodiments of the present specification are provided to more completely explain the present specification to those having ordinary skill in the art.

[0117] <Preparation example> Preparation of curable resin composition

[0118] Preparation Example 1

[0119] A curable resin composition 1 was prepared in the same manner as in Preparation Example 1, except that after 5 mass% of a maleimide compound containing a diphenylmethane structure (BMI-5100, Daiwakasei Industry Co., Ltd.), 15 mass% of a radically polymerizable resin (OPE-2St, Mitsubishi Gas Chemical Company, Inc.), 10 mass% of a high molecular weight resin containing a conjugated diene structure (1,2-H-SBS, Nippon Soda Co., Ltd.), and an inorganic filler (spherical silica, average particle diameter 0.5 μm, Admatechs SOC2) were added to a MEK (methyl ethyl ketone) solvent such that the content of the inorganic filler became 200 mass parts based on the total solid content of 100 mass parts of the maleimide compound containing a diphenylmethane structure, the radically polymerizable resin, and the high molecular weight resin containing a conjugated diene structure, the resulting mixture was stirred with a stirrer (250 rpm) for 3 hours.

[0120] Preparation Example 2

[0121] A curable resin composition 2 was prepared in the same manner as in Preparation Example 1, except that the maleimide compound containing a diphenylmethane structure (BMI-5100, Daiwakasei Industry Co., Ltd.) was changed to a maleimide compound containing a diphenylmethane structure (BMI-2300, Daiwakasei Industry Co., Ltd.).

[0122] Preparation Example 3

[0123] A curable resin composition 3 was prepared in the same manner as in Preparation Example 1, except that the high molecular weight resin containing a conjugated diene structure was changed from 1,2-H-SBS to 1,2-SBS-L42, and also the content of the inorganic filler was changed to the content shown in Table 1 below.

[0124] Preparation Example 4

[0125] A curable resin composition 4 was prepared in the same manner as in Preparation Example 1, except that the content of the inorganic filler was changed to the content shown in Table 1 below.

[0126] Comparative Preparation Example 1

[0127] A curable resin composition A was prepared in the same manner as in Preparation Example 1, except that a maleimide compound A containing a diphenylmethane structure (BMI-5100, Daiwakasei Industry Co., Ltd.) was changed to a maleimide compound C containing a biphenyl structure (MIR-3000-70MT, Nippon Kayaku Co., Ltd.).

[0128] Comparative Preparation Example 2

[0129] A curable resin composition B was prepared in the same manner as in Preparation Example 1, except that a high molecular weight resin containing a conjugated diene structure (1,2-H-SBS, Nippon Soda Co., Ltd.) was changed to a phenoxy resin (YX6954BH30, Mitsubishi Chemical Group Corporation).

[0130] Comparative Preparation Example 3

[0131] A curable resin composition C was each prepared in the same manner as in Preparation Example 1, except that the content of the inorganic filler was changed to the content shown in Table 1 below.

[0132] Comparative Preparation Example 4

[0133] A curable resin composition D was each prepared in the same manner as in Preparation Example 1, except that the type of the high molecular weight resin containing a conjugated diene structure and the content of the inorganic filler were changed to the contents shown in Table 1 below.

[0134] The composition and content (based on mass % (solid content)) of the curable resin compositions of Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 4 are shown in Table 1 below.

[0135] [Table 1]

[0136]

[0137] <Examples 1 to 4 and Comparative Examples 1 to 4> Preparation of Insulating Film

[0138] The curable resin compositions of Preparation Examples 1 to 4 and Comparative Preparation Examples 1 to 3 were each uniformly applied on a 40 μm PET film to a thickness of 20 μm, and then dried at 100°C for 5 minutes to prepare an insulating film having a thickness of 25 μm.

[0139] However, in the case of Comparative Preparation Example 4, the film coating surface was not uniformly formed due to insufficient wetting properties, and the curable resin composition could not be formed into a film, so Comparative Preparation Example 4 was not evaluated in the following experimental examples.

[0140] <Experimental Examples>

[0141] 1) Preparation of Samples

[0142] The insulating films of Examples 1 to 4 and Comparative Examples 1 to 3 were each heat-cured by heating at 200°C for 90 minutes, and the PET film as a support was peeled off to obtain cured samples.

[0143] 2) Experimental Example 1: Evaluation of Dielectric Properties

[0144] The dielectric constant and dissipation factor of the cured samples (thickness 100 μm) obtained from Examples 1 to 4 and Comparative Examples 1 to 3 were measured at 10 GHz under measurement temperature of 20°C to 25°C and humidity of 50% or less using an E5071C device manufactured by Agilent Technologies, Inc. The measurement results are shown in Table 2 below.

[0145] 3) Experimental Example 2: Evaluation of Linear Thermal Expansion Coefficient

[0146] The cured samples obtained from Examples 1 to 4 and Comparative Examples 1 to 3 were cut into test specimens having a width of about 5 mm and a length of about 15 mm, and were continuously measured twice using a TMA (Q400 manufactured by TA Instruments) under the following measurement conditions: a heating rate of 10°C / minute and 0°C to 300°C. In the second measurement, the average linear thermal expansion coefficient (ppm / °C) from 25°C to 120°C was determined. The measurement results are shown in Table 2 below.

[0147] 4) Experimental Example 3: Evaluation of Brittleness

[0148] When the cured samples obtained from the above Examples 1 to 4 and Comparative Examples 1 to 3 were bent by 90°, the number of times the cured samples cracked or broke was measured. The measurement criteria were as follows, and the measurement results are shown in Table 2 below.

[0149] O: the sample broke once or less (good) when bent 10 times

[0150] Δ: the sample broke two to four times (fair) when bent 10 times

[0151] X: the sample broke five or more times (poor) when bent 10 times

[0152] [Table 2]

[0153]

[0154] From Table 2 above, Examples 1 to 4 are excellent in dielectric constant, dissipation factor, linear thermal expansion coefficient, and brittleness, and are thus suitable for insulating films.

[0155] In contrast, it was determined that Comparative Example 1 had a slightly higher dissipation factor than the Examples, an excellent linear thermal expansion coefficient, but poor brittleness, and since Comparative Example 2 had a very high dissipation factor and poor brittleness, the linear thermal expansion coefficient was not even measured, and although Comparative Example 3 had improved brittleness, since both the dissipation factor and the linear thermal expansion coefficient of Comparative Example 3 were higher than those of the Examples, Comparative Example 3 was not suitable for an insulating film. Since Comparative Example 4 was not formed into a film, the dielectric properties, the linear thermal expansion coefficient, and the brittleness, which were to be measured based on a film, could not be measured.

Claims

1. A curable resin composition comprising: Maleimide compounds containing a diphenylmethane structure; Free radical polymerizable resin; High molecular weight resins containing conjugated diene structures; and Inorganic packing, The total solids content of the maleimide compound containing the diphenylmethane structure, the free radical polymerizable resin, and the high molecular weight resin containing the conjugated diene structure is 100 parts by mass, and the inorganic filler is included in an amount of 200 parts by mass or more and 400 parts by mass or less.

2. The curable resin composition according to claim 1, wherein the maleimide compound comprising a diphenylmethane structure is represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, R1 to R4 may be the same as or different from each other, and each is independently hydrogen; alkyl; aryl; heteroaryl; or a substituent represented by the following chemical formula 2, and at least one of R1 to R4 is a substituent represented by the following chemical formula 2. a and b are either the same or different from each other, and are each an independent integer from 0 to 5. When a and b are each an integer of 2 or greater, the substituents in parentheses are either the same or different from each other. [Chemical Formula 2] In chemical formula 2, It refers to the bond attached to chemical formula 1. L1 represents a direct bond; alkylene; arylene; or heteroarylene. R5 and R6 may be the same as or different from each other, and each is independently hydrogen; alkyl; aryl; or heteroaryl, and m is an integer from 0 to 4.

3. The curable resin composition according to claim 1, wherein the free radical polymerizable resin comprises unsaturated groups, and The unsaturated group is selected from (meth)acrylate, (meth)acrylamide, salts of organic acids, vinyl ether, allyl ether, vinyl ester, styrene, vinyl and allyl ester.

4. The curable resin composition according to claim 1, wherein the high molecular weight resin comprising a conjugated diene structure comprises, in at least one of the main chain and side chains, a unit represented by the following chemical formula 3: [Chemical Formula 3] In chemical formula 3, * indicates the location where it connects to another unit. R7 to R12 may be the same as or different from each other, and each is independently hydrogen; alkyl; aryl; or heteroaryl, and n is 90 or greater and 4000 or less.

5. The curable resin composition according to claim 1, wherein the weight-average molecular weight (MW) of the high molecular weight resin comprising the conjugated diene structure is 4,000 g / mol or greater and 200,000 g / mol or less.

6. The curable resin composition according to claim 1, wherein the average particle size of the inorganic filler is 1.0 μm or less.

7. The curable resin composition according to claim 1, further comprising additives and solvents, The additives mentioned therein are selected from leveling agents, wetting agents, antistatic agents, flame retardants, crosslinking agents, curing accelerators, curing agents, and polymerization initiators.

8. An insulating film comprising a curable resin composition or a cured product thereof according to any one of claims 1 to 7.

9. The insulating film according to claim 8, wherein the linear coefficient of thermal expansion measured according to ASTM D696 is 25 ppm / °C or less.

10. The insulating film of claim 8, wherein the dissipation factor (DF) measured at 10 GHz according to ASTM D2520 is 0.001 or greater and 0.004 or less.

11. A printed circuit board comprising the insulating film according to claim 8.

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