JP2019081893A - Curable resin composition, cured product, adhesive, and adhesive film - Google Patents

Abstract

To provide a curable resin composition that is excellent in adhesiveness, high-temperature long-term heat resistance, moisture absorption reflow resistance, plating resistance, and low exudation and embedding properties during quick press, and also provide a cured product of the curable resin composition, and an adhesive and an adhesive film prepared with the curable resin composition.SOLUTION: A curable resin composition contains a curable resin, an imide oligomer, and an inorganic filler, and has a 180°C melt viscosity of 10 kPa s or more and less than 1000 kPa s.SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition that is excellent in adhesiveness, high temperature long-term heat resistance, moisture absorption reflow resistance, plating resistance, and low bleeding and embedding during quick pressing. In addition, the present invention relates to a cured product of the curable resin composition, and an adhesive and an adhesive film formed using the curable resin composition.

In recent years, the use of flexible printed wiring boards (FPCs) has expanded to in-vehicle applications, and high-temperature long-term heat resistance is required for adhesives used for FPCs and coverlay films for protecting FPCs. As such an adhesive, a curable resin composition using a curable resin such as an epoxy resin which has a low shrinkage and is excellent in adhesion, insulation and chemical resistance is used, and in particular A curable resin composition capable of obtaining good results in a solder reflow test relating to heat resistance of time and a thermal cycle test relating to repeated heat resistance is often used.

As curable resin compositions excellent in heat resistance, for example, Patent Documents 1 and 2 disclose curable resin compositions containing an epoxy resin and an imide oligomer as a curing agent. However, a curable resin composition having an effect more excellent not only in heat resistance but also in adhesiveness, moisture absorption reflow resistance and plating resistance has been desired.

Patent Document 3 discloses a resin composition containing an inorganic filler having an average particle diameter of 1 nm or more and 500 nm or less. The resin composition disclosed in Patent Document 3 is considered to be excellent in moisture absorption reflow resistance and low exudation property when heated and pressurized. However, the resin composition disclosed in Patent Document 3 is insufficient in high temperature long-term heat resistance, or in a press system called quick press performed in the production or processing of FPC, the resin composition is sufficiently exuded. Problems that can not be suppressed.

JP 2007-91799 A Japanese Patent Application Laid-Open No. 61-270852 JP-A-2007-204696

An object of the present invention is to provide a curable resin composition which is excellent in adhesiveness, high temperature long-term heat resistance, moisture absorption reflow resistance, plating resistance, and low bleeding and embedding during quick pressing. Another object of the present invention is to provide a cured product of the curable resin composition, and an adhesive and an adhesive film formed using the curable resin composition.

The present invention is a curable resin composition containing a curable resin, an imide oligomer, and an inorganic filler, and having a melt viscosity at 180 ° C. of 10 kPa · s or more and less than 1000 kPa · s.
The present invention will be described in detail below.

The present inventors further studied that an inorganic filler was further added to a curable resin composition containing a curable resin and an imide oligomer, and that the melt viscosity of the entire composition was within a specific range. . As a result, it has been found that a curable resin composition excellent in adhesiveness, high temperature long term heat resistance, moisture absorption reflow resistance, plating resistance, and low bleeding and embedding during quick pressing can be obtained, and the present invention is completed. It came to

The curable resin composition of the present invention contains a curable resin.
An epoxy resin is preferably used as the curable resin.

Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, bisphenol S epoxy resin, 2,2'-diallyl bisphenol A epoxy resin, hydrogenated bisphenol epoxy resin Propylene oxide added bisphenol A type epoxy resin, resorcinol type epoxy resin, biphenyl type epoxy resin, sulfide type epoxy resin, diphenyl ether type epoxy resin, dicyclopentadiene type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, naphthylene ether Epoxy resin, phenol novolac epoxy resin, ortho cresol novolac epoxy resin, dicyclopentadiene novolac epoxy resin, bif Nirunoborakku type epoxy resins, naphthalene phenol novolac-type epoxy resin, glycidyl amine type epoxy resin, alkyl polyol type epoxy resin, rubber modified epoxy resin, fluorene type epoxy resins, glycidyl ester compounds. Among them, since the viscosity is low and the processability at room temperature of the resulting curable resin composition can be easily adjusted, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E epoxy resin, resorcinol epoxy resin, etc. An epoxy resin which is liquid at normal temperature is preferred. The epoxy resins may be used alone or in combination of two or more.

The curable resin composition of the present invention contains an imide oligomer.
The imide oligomer preferably has a reactive functional group capable of reacting with the curable resin.
Although the said reactive functional group is based also on the kind of curable resin to be used, when using an epoxy resin as curable resin, it is preferable that they are an acid anhydride group and / or phenolic hydroxyl group.
The imide oligomer preferably has the reactive functional group at the end of the main chain, and more preferably at both ends of the main chain.

The imide oligomer having an acid anhydride group as the reactive functional group is, for example, a segment derived from an acid dianhydride represented by the following formula (1) and a diamine represented by the following formula (2) The imide oligomer etc. which have a segment are mentioned. In this case, it is preferable to have a segment derived from an acid dianhydride represented by the following formula (1) at the end of the main chain, and more preferably at both ends of the main chain.

In Formula (1), A is a tetravalent group represented by the following Formula (3-1) or the following Formula (3-2).

In formula (2), B is a divalent group represented by the following formula (4-1) or the following formula (4-2), and R ^{1 to} R ⁴ are each independently a hydrogen atom or 1 Hydrocarbon group.

In formulas (3-1) and (3-2), * is a bonding position, and in formula (3-1), Z is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a bond A linear or branched divalent hydrocarbon group which may have an oxygen atom at a position, or a divalent group having an aromatic ring which may have an oxygen atom at a bonding position . The hydrogen atom of the aromatic ring in Formula (3-1) and Formula (3-2) may be substituted.

In formulas (4-1) and (4-2), * is a bonding position, and in formula (4-1), Y is a bond, an oxygen atom, a carbonyl group, a sulfur atom, a sulfonyl group, a bond A linear or branched divalent hydrocarbon group which may have an oxygen atom at a position, or a divalent group having an aromatic ring which may have an oxygen atom at a bonding position . In the phenylene group in the formulas (4-1) and (4-2), part or all of the hydrogen atoms may be substituted by a hydroxyl group or a monovalent hydrocarbon group.

As a method for producing an imide oligomer having an acid anhydride group as the reactive functional group, for example, a reaction of an acid dianhydride represented by the above formula (1) and a diamine represented by the above formula (2) And the like.

The specific example of the method of making the acid dianhydride represented by said Formula (1) and the diamine represented by the said Formula (2) react is shown below.
First, a solution obtained by dissolving in advance a diamine represented by the above formula (2) in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc.) The acid dianhydride represented by the above-mentioned formula (1) is added to the mixture and reacted to obtain an amic acid oligomer solution. Then, the solvent is removed from the obtained amic acid oligomer solution by heating or reduced pressure or the like, or the solution is introduced into a poor solvent such as water, methanol, hexane and the like to reprecipitate to recover the amic acid oligomer, and The imidation reaction is allowed to proceed by heating at 200 ° C. or more for 1 hour or more. By adjusting the molar ratio between the acid dianhydride represented by the above formula (1) and the diamine represented by the above formula (2) and the imidization conditions, it has a desired number average molecular weight, An imide oligomer having an acid anhydride group as a reactive functional group at the end can be obtained.

Moreover, as an imido oligomer having a phenolic hydroxyl group as the reactive functional group, for example, a segment derived from the acid dianhydride represented by the formula (1) and a phenolic hydroxyl group represented by the following formula (5) The imide oligomer etc. which have a segment derived from containing monoamine etc. are mentioned. In this case, it is preferable to have a segment derived from a phenolic hydroxyl group-containing monoamine represented by the following formula (5) at the end of the main chain, more preferably at both ends of the main chain.

In the formula (5), Ar is a divalent aromatic group which may be substituted, and R ⁵ and R ⁶ are each independently a hydrogen atom or a monovalent hydrocarbon group.

As a method of manufacturing the imide oligomer which has phenolic hydroxyl group as said reactive functional group, the following method etc. are mentioned, for example.
That is, a method of reacting the acid dianhydride represented by the formula (1) with the phenolic hydroxyl group-containing monoamine represented by the formula (5), or the acid dianhydride represented by the formula (1) The method of making the phenolic hydroxyl group containing monoamine represented by said Formula (5), etc. be made to react, after making the diamine represented by said, and the said Formula (2) react.

The specific example of the method of making the acid dianhydride represented by said Formula (1) and the phenolic hydroxyl group containing monoamine represented with said Formula (5) is shown below.
First, the phenolic hydroxyl group-containing monoamine represented by the above formula (5) is dissolved in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc.) The acid dianhydride represented by the above formula (1) is added to the obtained solution and reacted to obtain an amic acid oligomer solution. Then, the solvent is removed from the obtained amic acid oligomer solution by heating or reduced pressure or the like, or the solution is introduced into a poor solvent such as water, methanol, hexane and the like to reprecipitate to recover the amic acid oligomer, and The imidation reaction is allowed to proceed by heating at 200 ° C. or more for 1 hour or more. By adjusting the molar ratio of the acid dianhydride represented by the above formula (1) to the phenolic hydroxyl group-containing monoamine represented by the above formula (5), and the imidization conditions, a desired number average molecular weight can be obtained It is possible to obtain an imide oligomer having a phenolic hydroxyl group as a reactive functional group at both ends.

A method of reacting the acid dianhydride represented by the above formula (1) and the diamine represented by the above formula (2), and further reacting the phenolic hydroxyl group-containing monoamine represented by the above formula (5) Specific examples of are shown below.
First, a solution obtained by dissolving in advance a diamine represented by the above formula (2) in a solvent in which the amic acid oligomer obtained by the reaction is soluble (for example, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc.) The acid dianhydride represented by the above-mentioned formula (1) is added to the mixture and reacted to obtain a solution of an amic acid oligomer (A) having an acid anhydride group at both ends. Next, the solvent is removed from the obtained solution of the amic acid oligomer (A) by heating or reduced pressure or the like, or the solution is introduced into a poor solvent such as water, methanol, hexane or the like to reprecipitate, thereby amic acid oligomer (A) The reaction mixture is further heated at about 200.degree. C. or more for 1 hour or more to advance the imidation reaction.
The imide oligomer having an acid anhydride group as a reactive functional group at both ends, thus obtained, is dissolved again in a solvent (eg, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc.) The phenolic hydroxyl group-containing monoamine represented by 5) is added and reacted to obtain a solution of an amic acid oligomer (B). The solvent is removed from the obtained solution of the amic acid oligomer (B) by heating or reduced pressure or the like, or the solution is poured into a poor solvent such as water, methanol, hexane or the like to reprecipitate to recover the amic acid oligomer (B) Further, the imidation reaction is allowed to proceed by heating at about 200 ° C. or more for one hour or more. The molar ratio between the acid dianhydride represented by the above formula (1), the diamine represented by the above formula (2) and the phenolic hydroxyl group-containing monoamine represented by the above formula (5), and the imidization conditions By adjusting, it is possible to obtain an imide oligomer having a desired number average molecular weight and having a phenolic hydroxyl group as a reactive functional group at both ends.

As the acid dianhydride represented by the above formula (1), for example, pyromellitic dianhydride, 3,3′-oxydiphthalic dianhydride, 3,4′-oxydiphthalic dianhydride, 4,4 '-Oxydiphthalic dianhydride, 4,4'-(4,4'-isopropylidenediphenoxy) diphthalic anhydride, 4,4'-bis (3,4-dicarboxylphenoxy) diphenyl ether, p-phenylene bis (Trimellitate anhydride), 2,3,3 ', 4'-biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 4,4'-carbonyldiphthalic acid An acid dianhydride etc. are mentioned. Among these, 4,4 ′-(4,4′-isopropylidenediphenoxy) diphthalic anhydride, 3,4 from the viewpoints of controlling the softening point and solubility of the imide oligomer, controlling the heat resistance, and obtaining excellent availability. '-Oxydiphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-carbonyldiphthalic dianhydride are preferred.

Examples of the diamine represented by the above formula (2) include 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenyl ether, and 3,4. '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl Sulfone, bis (4- (3-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) sulfone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4) -Aminophenoxy) benzene, 1,4-bis (4-aminophen) Xy) Benzene, bis (4- (4-aminophenoxy) phenyl) methane, 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 1,3-bis (2- (4-aminophenyl) -2-propyl) benzene, 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene, 3,3'-diamino-4,4'-dihydroxyphenylmethane, 4,4'-diamino -3,3'-Dihydroxyphenylmethane, 3,3'-diamino-4,4'-dihydroxyphenyl ether, bisaminophenyl fluorene, bis toluidine fluorene, 4,4'-bis (4-aminophenoxy) biphenyl, 4 4,4'-diamino-3,3'-dihydroxyphenyl ether, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4 - diamino-2,2'-dihydroxybiphenyl, 3,3'-dihydroxy-benzidine, and the like. Among these, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, 1,2-phenylenediamine, 1 because they are excellent in control of softening point and solubility of imide oligomer, heat resistance and availability. , 3-phenylenediamine, 1,4-phenylenediamine, bis (4- (3-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) sulfone, 1,3-bis (2- 4-aminophenyl) -2-propyl) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene, 3,3 ′ -Dihydroxy benzidine is preferred.

Examples of phenolic hydroxyl group-containing monoamines represented by the above formula (5) include 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o-cresol, 4-amino-2 3, 3-xylenol, 4-amino-2, 5-xylenol, 4-amino-2, 6-xylenol, 4-amino-1-naphthol, 5-amino-2-naphthol, 6-amino-1-naphthol, 4 -Amino-2, 6- diphenyl phenol etc. are mentioned. Among them, 3-aminophenol, 4-aminophenol, 4-amino-o-cresol, 5-amino-o-, because they are excellent in availability and storage stability, and a cured product having a high glass transition temperature is obtained. Cresol is preferred.

The preferable lower limit of the imidation ratio of the imide oligomer is 70%. By the said imidation ratio being 70% or more, the hardened | cured material which is excellent by the mechanical strength in high temperature, and high temperature long-term heat resistance can be obtained. A more preferable lower limit of the imidation ratio is 75%, and a still more preferable lower limit is 80%. Moreover, although the preferable upper limit in particular of the imidation ratio of the said imide oligomer does not have it, a substantial upper limit is 98%.
In addition, the said "imidation ratio" can be calculated | required by Fourier-transform infrared spectroscopy (FT-IR). Specifically, measurement is performed by total reflection measurement method (ATR method) using a Fourier transform infrared spectrophotometer, and the peak absorbance area around 1660 cm ⁻¹ derived from the carbonyl group of amic acid is expressed by the following equation It can be derived. As said Fourier-transform infrared spectrophotometer, UMA600 (made by Agilent Technologies) etc. are mentioned, for example. Further, “peak absorbance area of amic acid oligomer” in the following formula is the absorbance area of the amic acid oligomer obtained by removing the solvent without performing the imidization step in each method for producing the imide oligomer described above. is there. The solvent can be removed by evaporation.
Imidation ratio (%) = 100 × (1− (peak absorbance area after imidization) / (peak absorbance area of amic acid oligomer))

The imide oligomers may be used alone or in combination of two or more.

The preferable lower limit of the number average molecular weight of the imide oligomer is 400, and the preferable upper limit is 5000. By the said number average molecular weight being this range, the hardened | cured material obtained becomes what is excellent by adhesiveness and high temperature long-term heat resistance. The more preferable lower limit of the number average molecular weight of the imide oligomer is 500, and the more preferable upper limit is 4000.
In the present specification, the above-mentioned "number average molecular weight" is a value determined by gel permeation chromatography (GPC) and converted to polystyrene. As a column used when measuring the number average molecular weight by polystyrene conversion by GPC, JAIGEL-2H-A (made by Japan Analysis Industry Co., Ltd.) etc. are mentioned, for example.

The preferable upper limit of the softening point of the imide oligomer is 250 ° C. By the softening point of the said imide oligomer being 250 degrees C or less, the hardened | cured material obtained becomes what is excellent by adhesiveness and high temperature long-term heat resistance. A more preferable upper limit of the softening point of the imide oligomer is 200 ° C.
There is no particular lower limit of the softening point of the above imide oligomer, but the substantial lower limit is 60.degree.
The softening point of the imide oligomer can be determined by the ring and ball method according to JIS K 2207.

The preferable upper limit of the melting point of the imide oligomer is 300 ° C. When the melting point of the imide oligomer is 300 ° C. or less, the resulting curable resin composition is excellent in adhesiveness and high temperature long-term heat resistance. A more preferable upper limit of the melting point of the imide oligomer is 250 ° C.
The melting point of the imide oligomer can be determined by differential scanning calorimetry or a commercially available melting point measuring device.

The preferable lower limit of the content of the imide oligomer in the total 100 parts by weight of the curable resin and the imide oligomer is 10 parts by weight, and the preferable upper limit is 90 parts by weight. When the content of the imide oligomer is in this range, the cured product of the curable resin composition obtained is excellent in mechanical strength at high temperature, adhesiveness, and high temperature long-term heat resistance. A more preferable lower limit of the content of the imide oligomer is 20 parts by weight, and a more preferable upper limit is 80 parts by weight.

The curable resin composition of the present invention may contain another curing agent in addition to the imide oligomer as long as the object of the present invention is not impaired.
Examples of the other curing agent include phenol-based curing agents, thiol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, cyanate-based curing agents, active ester-based curing agents, and the like. Among them, phenolic curing agents, acid anhydride curing agents, cyanate curing agents, and active ester curing agents are preferable.

When the curable resin composition of the present invention contains the other curing agent, the upper limit of the content ratio of the other curing agent in the total 100 parts by weight of the imide oligomer and the other curing agent is 70 weight The upper limit is preferably 50 parts by weight, and more preferably 30 parts by weight.

The curable resin composition of the present invention contains an inorganic filler.
By containing the above inorganic filler, the curable resin composition of the present invention exhibits moisture absorption reflow resistance, plating resistance, and low bleeding during quick pressing while maintaining excellent adhesion and high temperature long-term heat resistance. It will be excellent in

The inorganic filler is preferably at least one of silica and barium sulfate. By containing at least one of silica and barium sulfate as the above-mentioned inorganic filler, the curable resin composition of the present invention is excellent in moisture absorption reflow resistance, plating resistance, and low bleeding out during quick pressing. Become.

Examples of the above-mentioned silica and other inorganic fillers other than the above-mentioned barium sulfate include alumina, aluminum nitride, boron nitride, silicon nitride, glass powder, glass frit, glass fiber, carbon fiber, inorganic ion exchanger and the like.

The above inorganic fillers may be used alone or in combination of two or more.

The preferable upper limit of the average particle size of the inorganic filler is 4 μm. When the average particle diameter of the inorganic filler is 4 μm or less, the resulting curable resin composition becomes excellent due to the low bleeding property at the time of quick pressing. A more preferable upper limit of the average particle size of the inorganic filler is 3 μm.
In addition, from the viewpoint of making the coating property and the embedding property at the time of quick pressing preferable, the preferable lower limit of the average particle diameter of the inorganic filler is 5 nm, and the more preferable lower limit is 10 nm.
In addition, the average particle diameter of the said inorganic filler and the flow control agent mentioned later disperses the said inorganic filler and flow control agent in solvent (water, organic solvent etc.), for example using a particle size distribution analyzer, and measures it. can do. As said particle size distribution measuring apparatus, NICOMP 380ZLS (made by PARTICLE SIZING SYSTEMS company) etc. are mentioned, for example.

The preferable lower limit of the content of the inorganic filler is 10 parts by weight and the preferable upper limit is 150 parts by weight with respect to 100 parts by weight in total of the curable resin and the imide oligomer. When the content of the inorganic filler is 10 parts by weight or more, the resulting curable resin composition is excellent in moisture absorption reflow resistance, plating resistance, and low exudation property at the time of quick pressing. When the content of the inorganic filler is 150 parts by weight or less, the resulting curable resin composition is excellent in adhesiveness and embeddability at the time of quick pressing. A more preferable lower limit of the content of the inorganic filler is 20 parts by weight.

The curable resin composition of the present invention may contain, in addition to the above-mentioned inorganic filler, a flow control agent for the purpose of improving the wettability to an adherend and the shape retention in a short time, etc. .
Examples of the flow control agent include fumed silica such as Aerosil and layered silicates.
Moreover, as said flow control agent, that whose average particle diameter is less than 100 nm is used suitably.

The preferable lower limit of the content of the flow control agent is 0.1 parts by weight and the preferable upper limit is 50 parts by weight with respect to 100 parts by weight in total of the curable resin and the imide oligomer. When the content of the flow control agent is in this range, the effect of improving the wettability and the shape retention in a short time to the adherend can be improved. The more preferable lower limit of the content of the flow control agent is 0.5 parts by weight, and the more preferable upper limit is 30 parts by weight.

The curable resin composition of the present invention may contain an organic filler for the purpose of stress relaxation, imparting of toughness and the like.
Examples of the organic filler include silicone rubber particles, acrylic rubber particles, urethane rubber particles, polyamide particles, polyamideimide particles, polyimide particles, benzoguanamine particles, and core-shell particles thereof. Among them, polyamide particles, polyamide imide particles and polyimide particles are preferable.

The upper limit of the content of the organic filler is preferably 300 parts by weight with respect to 100 parts by weight in total of the curable resin and the imide oligomer. When the content of the organic filler is in this range, the obtained cured product is excellent in toughness and the like while maintaining excellent adhesion and the like. A more preferable upper limit of the content of the organic filler is 200 parts by weight.

The curable resin composition of the present invention may contain a flame retardant for the purpose of imparting flame retardancy.
As said flame retardant, metal hydrates, such as a boehmite type aluminum hydroxide, aluminum hydroxide, magnesium hydroxide, a halogen type compound, a phosphorus type compound, a nitrogen compound etc. are mentioned, for example. Among these, boehmite type aluminum hydroxide is preferable.

With respect to the content of the flame retardant, the preferable lower limit is 5 parts by weight and the preferable upper limit is 200 parts by weight with respect to 100 parts by weight in total of the curable resin and the imide oligomer. When the content of the flame retardant is in this range, the resulting curable resin composition becomes excellent in flame retardancy while maintaining excellent adhesiveness and the like. The more preferable lower limit of the content of the flame retardant is 10 parts by weight, and the more preferable upper limit is 150 parts by weight.

The curable resin composition of the present invention preferably contains a curing accelerator. By containing the said hardening accelerator, hardening time can be shortened and productivity can be improved.

Examples of the curing accelerator include imidazole curing accelerator, tertiary amine curing accelerator, phosphine curing accelerator, phosphorus curing accelerator, photo base generator, sulfonium salt curing accelerator and the like. . Among them, an imidazole-based curing accelerator is preferable because of excellent storage stability.

The content of the curing accelerator is preferably 0.01 parts by weight with a preferable lower limit and 10 parts by weight with a preferable upper limit based on 100 parts by weight in total of the curable resin and the imide oligomer. When the content of the curing accelerator is in this range, the curing time can be shortened while maintaining excellent adhesiveness and the like. A more preferable lower limit of the content of the curing accelerator is 0.05 parts by weight, and a more preferable upper limit is 5 parts by weight.

The curable resin composition of the present invention may contain a polymer compound as long as the object of the present invention is not impaired. The said high molecular compound plays a role of a film-forming component.

The polymer compound may have a reactive functional group.
When the polymer compound has a reactive functional group, examples of the reactive functional group that the polymer compound has include an amino group, a urethane group, an imide group, a hydroxyl group, a carboxyl group, an epoxy group and the like.

The curable resin composition of the present invention may contain a reactive diluent as long as the object of the present invention is not impaired.
From the viewpoint of adhesion reliability, a reactive diluent having two or more reactive functional groups in one molecule is preferable as the above-mentioned reactive diluent.
As a reactive functional group which the said reactive diluent has, the thing similar to the reactive functional group which the high molecular compound mentioned above has is mentioned.

The curable resin composition of the present invention may further contain additives such as a solvent, a coupling agent, a dispersant, a storage stabilizer, a bleed inhibitor, a flux agent, and a leveling agent.
Methyl ethyl ketone is preferably used as the solvent.

As a method for producing the curable resin composition of the present invention, for example, a curable resin, an imide oligomer, an inorganic filler, and a necessary agent using a mixer such as a homodisper, a universal mixer, a Banbury mixer, or a kneader. And the method of mixing with a hardening accelerator, a flow control agent, etc. which are added according to the above.

The curable resin composition of the present invention has a melt viscosity at 180 ° C. of 10 kPa · s or more and less than 1000 kPa · s. When the melt viscosity at 180 ° C. is 10 kPa · s or more, the curable resin composition of the present invention is excellent in moisture absorption reflow resistance, plating resistance, and low bleeding during quick pressing. When the melt viscosity at 180 ° C. is less than 1000 kPa · s, the curable resin composition of the present invention is excellent in adhesiveness and embeddability at the time of quick pressing. The preferable lower limit of the melt viscosity at 180 ° C. is 20 kPa · s, the preferable upper limit is 900 kPa · s, the more preferable lower limit is 50 kPa · s, and the more preferable upper limit is 850 kPa · s.
The melt viscosity at 180 ° C. is raised by using a rotary rheometer for the curable resin composition (curable resin composition film) in the B-stage state from which the solvent has been removed by a coating drying step or the like. It is determined as the viscosity at 180 ° C. when the viscosity is measured while heating at a temperature rate of 10 ° C./min. Examples of the rotary rheometer include HAAKE MARS series (manufactured by Thermo Fisher Scientific Co., Ltd.), VAR-100 (manufactured by Rheologica Co., Ltd.), and the like.

The curable resin composition of the present invention can be used for a wide range of applications, but can be suitably used for electronic materials where high heat resistance is required. For example, it can be used as a die attach agent in aviation, in-vehicle electrical control unit (ECU) applications, power devices using SiC, GaN, and the like. For example, adhesives for power overlay packages, sealants, adhesives for flexible printed circuit boards or coverlay films, copper-clad laminates, adhesives for semiconductor bonding, interlayer insulating films, prepregs, sealants for LEDs, structures It can also be used as an adhesive for materials and the like. Especially, it is used suitably for adhesion | attachment of a flexible printed circuit board or a coverlay film.

The cured product of the curable resin composition of the present invention is also one of the present invention.
An adhesive using the curable resin composition of the present invention is also one of the present invention. An adhesive film can be obtained by a method such as drying after applying the adhesive of the present invention on a film. An adhesive film using the adhesive of the present invention is also one of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which is excellent in adhesiveness, high temperature long-term heat resistance, moisture absorption reflow tolerance, plating tolerance, and low ooze-out property and embedding property at the time of a quick press can be provided. Further, according to the present invention, it is possible to provide a cured product of the curable resin composition, and an adhesive and an adhesive film formed using the curable resin composition.

EXAMPLES The present invention will be described in more detail by way of the following examples, but the present invention is not limited to these examples.

Synthesis Example 1 Preparation of Imide Oligomer A
17.2 parts by weight of 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene were dissolved in 200 parts by weight of N-methylpyrrolidone. As 1,4-bis (2- (4-aminophenyl) -2-propyl) benzene, bisaniline P (manufactured by Mitsui Chemicals Fine Inc.) is used, and as N-methylpyrrolidone, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. The reagent was used. 52.0 parts by weight of 4,4 '-(4,4'-isopropylidenediphenoxy) diphthalic anhydride is added to the obtained solution, and the mixture is reacted by stirring at 25 ° C for 2 hours to react with amic acid oligomer solution Obtained. A reagent manufactured by Tokyo Chemical Industry Co., Ltd. was used as 4,4 '-(4,4'-isopropylidene diphenoxy) diphthalic anhydride. The N-methylpyrrolidone was removed under reduced pressure from the obtained amic acid oligomer solution, and then heated at 300 ° C. for 2 hours to obtain an imide oligomer A (imidation ratio of 97%).
In addition, the imide oligomer A confirmed having imide oligomer represented by following formula (6) as a main component by < ¹ > H-NMR, GPC, and FT-IR analysis. Moreover, the softening point of the imide oligomer A was 155 ° C., and the melting point was 170 ° C.

Synthesis Example 2 Preparation of Imide Oligomer B
21.8 parts by weight of 3-aminophenol was dissolved in 200 parts by weight of N-methylpyrrolidone. 17.2 parts by weight of 4,4 '-(4,4'-isopropylidenediphenoxy) diphthalic anhydride is added to the obtained solution, and the mixture is reacted by stirring at 25 ° C. for 2 hours to make the amic acid oligomer solution Obtained. The N-methylpyrrolidone was removed from the obtained amic acid oligomer solution under reduced pressure, and then heated at 300 ° C. for 2 hours to obtain an imide oligomer B (imidation ratio 96%).
In addition, the imide oligomer B confirmed having imide oligomer represented by following formula (7) as a main component by < ¹ > H-NMR, GPC, and FT-IR analysis. Further, the softening point of the imide oligomer B was 134 ° C., and the melting point was 154 ° C.

(Examples 1 to 9, Comparative Examples 1 to 4)
Each material was stirred and mixed according to the compounding ratio described in Table 1, and each curable resin composition of Examples 1-9 and Comparative Examples 1-4 was produced.
The obtained curable resin composition was coated on a release PET film so as to have a thickness of about 20 μm and dried to obtain a curable resin composition film. Melt viscosity at 180 ° C when viscosity was measured while peeling the PET film from the obtained curable resin composition film and heating it under the conditions of a frequency of 1 Hz and a temperature rising rate of 10 ° C / min using a rotary rheometer Was measured. HAAKE MARS III (manufactured by Thermo Fisher Scientific Co., Ltd.) was used as a rotary rheometer. The results are shown in Table 1.

<Evaluation>
The following evaluation was performed about each curable resin composition obtained by the Example and the comparative example. The results are shown in Table 1.

(Adhesiveness)
Each curable resin composition obtained in Examples and Comparative Examples was coated on a release PET film so as to have a thickness of about 20 μm and dried to obtain an adhesive film. The PET film was peeled off from the obtained adhesive film, and a polyimide substrate (50 μm in thickness) was attached to both surfaces of the adhesive layer while heating to 80 ° C. using a laminator. Kapton 200H (manufactured by Toray Dupont) was used as the polyimide substrate. After hot pressing under conditions of 190 ° C., 3 MPa and 1 hour to cure the adhesive layer, it was cut out into a width of 1 cm to obtain a test piece.
The obtained test piece was subjected to T-peel at a peeling rate of 20 mm / min with a tensile tester to measure adhesion. UCT-500 (manufactured by ORIENTEC) was used as a tensile tester.
If the adhesive strength is 3.4 N / cm or more, “○”, if 2.0 or more and less than 3.4 N / cm, if “Δ”, if less than 2.0 N / cm The adhesion was evaluated as "x".

(High temperature long term heat resistance)
About the test piece obtained by carrying out similarly to evaluation of said "(adhesiveness)", heat processing was performed at 175 degreeC for 1000 hours. The test pieces after heat treatment were subjected to T-peel at a peel rate of 20 mm / min using a tensile tester to measure adhesion. UCT-500 (manufactured by ORIENTEC) was used as a tensile tester.
If the adhesive strength is 3.4 N / cm or more, “○”, if 2.0 or more and less than 3.4 N / cm, if “Δ”, if less than 2.0 N / cm The high temperature long-term heat resistance was evaluated as "x".

(Resistance reflow resistance)
The test pieces obtained in the same manner as the evaluation of “(adhesiveness)” were subjected to a moisture absorption reflow test in which the test pieces were left in an environment of 40 ° C. and 90% RH for 3 days and then heated at 260 ° C. for 20 seconds. The presence or absence of air bubbles was visually confirmed for the test pieces after the moisture absorption reflow test.
The moisture absorption reflow resistance was evaluated by setting the case where no bubble was confirmed as “O” and the case where the bubble was confirmed as “X”.

(Quick press)
An adhesive film was obtained by applying each curable resin composition obtained in Examples and Comparative Examples on a polyimide substrate (thickness 25 μm) to a thickness of about 20 μm and drying. Kapton 100H (manufactured by Toray Dupont) was used as the polyimide substrate. The resulting adhesive film is provided with an opening of 10 mm × 10 mm, and bonded to a copper-clad laminate consisting of a copper wiring pattern of L / S = 100 μm / 100 μm and a thickness of 18 μm and a polyimide film of 50 μm thickness. Was produced. In addition, bonding was performed by the quick press system on 180 degreeC, the vacuum, and the conditions of 3 MPa of press pressures for 5 minutes using a slide-type vacuum heater press. As a slide type vacuum heater press, MKP-3000V (made by Mikado Technos Co., Ltd.) was used.
About the obtained sample for FPC evaluation, the adhesive film edge part of an opening part was observed with the optical microscope, and the amount of oozing out of the curable resin composition (the length of the part which exudeed most) was measured.
In addition, after the cross-section of the test piece after quick pressing is polished, it is observed with an optical microscope, and a case where no void is confirmed between copper wiring patterns is indicated as “○” and a case where a void is confirmed is indicated as “x”. The sex was evaluated.

(Plating resistance)
About the sample for FPC evaluation obtained by the above-mentioned "(quick press)" evaluation, using a commercially available electroless nickel plating bath and electroless gold plating bath, at 80 ° C. to 90 ° C., nickel 5 μm, gold 0 Plating was performed under the condition of .05 μm. The edge of the adhesive film at the opening is observed with an optical microscope, and when the leaching of the plating solution is not confirmed, "○", and when the leaching of the plating solution is confirmed at the end, "×" evaluated.

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which is excellent in adhesiveness, high temperature long-term heat resistance, moisture absorption reflow tolerance, plating tolerance, and low ooze-out property and embedding property at the time of a quick press can be provided. Further, according to the present invention, it is possible to provide a cured product of the curable resin composition, and an adhesive and an adhesive film formed using the curable resin composition.

Claims (11)

Containing a curable resin, an imide oligomer, and an inorganic filler,
A curable resin composition characterized in that the melt viscosity at 180 ° C. is 10 kPa · s or more and less than 1000 kPa · s. The curable resin composition according to claim 1, wherein the inorganic filler contains at least one of silica and barium sulfate. The curable resin composition according to claim 1, wherein the inorganic filler has an average particle diameter of 5 nm or more and 4 μm or less. 4. The curable resin composition according to claim 1, wherein the content of the inorganic filler is 10 parts by weight or more and 150 parts by weight or less based on 100 parts by weight in total of the curable resin and the imide oligomer. The curable resin composition according to claim 1, 2, 3 or 4, wherein the imide oligomer has a reactive functional group capable of reacting with the curable resin. The curable resin composition according to claim 5, wherein the reactive functional group is an acid anhydride group and / or a phenolic hydroxyl group. The curable resin composition according to claim 1, 2, 3, 4, 5, or 6, wherein the imidation ratio of the imide oligomer is 70% or more. The curable resin composition according to claim 1, 2, 3, 4, 5, 6, or 7, which is used for adhesion of a flexible printed substrate or a coverlay film. The hardened | cured material of the curable resin composition of Claim 1, 2, 3, 4, 5, 6, 7 or 8. An adhesive comprising the curable resin composition according to claim 1, 2, 3, 4, 5, 6, 7 or 8. An adhesive film comprising the adhesive according to claim 10.