TW201319180A - Liquid ink - Google Patents

Abstract

A liquid ink including a thermosetting resin composition and a solvent for dissolving or dispersing the thermosetting resin composition is provided, wherein the thermosetting resin composition contains an organic polymer, a thermosetting resin and inorganic fillers. When the thermosetting resin composition is cured, a hardener 1 is formed in which a storage modulus at 25 DEG C is 500MPa or less and a tension elastic modulus ranges from 0.5GPa to 3.0GPa.

Description

Liquid ink

This invention relates to a liquid ink.

Previously, various printed wiring boards of one-sided, double-sided or multi-layer were widely used in the field of industrial machines or livelihood machines. There are few cases where only one printed wiring board is used in an electronic device. For example, a plurality of printed wiring boards classified by function are generally used. Usually, a plurality of wiring boards are connected by various connectors.

Electronic devices are becoming lighter and thinner, especially in recent years in mobile phones, video cameras, and notebook personal computers, which are assembled into high-density printed printed wiring boards that are light and thin. In these electronic machines, it is necessary to compactly pack a plurality of printed wiring boards in a limited space. However, when the substrates of the wiring boards are connected by a connector, the volume becomes large, and thus connection by the connector becomes difficult. Therefore, various so-called flexible-rigid wiring boards in which a flexible substrate such as a polyimide film substrate and a rigid substrate are combined have been proposed.

For example, a method for manufacturing a rigid flexible wiring board is proposed in which a rigid substrate and a flexible substrate are thermocompression-bonded via an adhesive sheet, and a rigid substrate is electrically connected to a circuit of the flexible substrate by using a through hole (for example, refer to the patent document) 1).

In addition, it is proposed to have a rigidity In a method of manufacturing a substrate, a flexible substrate having no flexibility is laminated on a flexible flexible substrate, and an opening is partially provided on the rigid substrate to expose the flexible substrate, thereby partially providing Flexibility (for example, refer to Patent Document 2).

Furthermore, it has been proposed to partially increase the thickness of the conductor portion of the printed wiring board, and to provide rigidity in part (for example, see Patent Document 3).

Prior technical literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 2-359594

Patent Document 2: Japanese Patent Laid-Open No. Hei 5-90756

Patent Document 3: Japanese Patent Laid-Open Publication No. 2006-352103

A main object of the present invention is to provide a liquid ink which can improve a bendability of a substrate such as a flexible printed wiring board while maintaining an excellent bending property and an arbitrary portion which does not require bending property. rigidity.

The present invention relates to a liquid ink comprising a thermosetting resin composition containing an organic polymer, a thermosetting resin, and an inorganic filler, and a solvent for dissolving or dispersing the thermosetting resin composition. When the thermosetting resin composition is cured, a cured product having a storage elastic modulus of 500 MPa or less and a tensile elastic modulus of 0.5 GPa to 3.0 GPa at 25 ° C can be formed.

According to the liquid ink of the present invention, the cured product of the thermosetting resin composition to which the inorganic filler is added has the above-described specific storage elastic modulus and tensile elastic modulus, and therefore has flexibility for a flexible printed wiring board or the like. The base material can improve the rigidity of any portion that does not require bending while maintaining good bending properties.

The thermosetting resin composition may contain 50% by mass or more of an inorganic filler based on the total solid content of the thermosetting resin composition (component other than the solvent among the liquid inks). In addition, the organic polymer may contain an acrylic resin. Thereby, a thermosetting resin having a cured product having the above-described specific storage elastic modulus and tensile modulus of elasticity is particularly easily formed.

The acrylic resin may have a glycidyl group. The weight average molecular weight of the acrylic resin may range from 400,000 to 1.8 million, 500,000 to 1.5 million, or 800,000 to 1.4 million.

The inorganic filler may contain cerium oxide particles. The cerium oxide particles may be surface treated by a silane coupling agent. Thereby, precipitation of cerium oxide particles is suppressed, and a liquid ink having higher stability can be obtained. From the same viewpoint, the decane coupling agent may have an amino group.

The thermosetting resin may contain an epoxy resin. In this case, the thermosetting resin composition may further contain a phenol resin.

The epoxy resin may contain a biphenyl aralkyl type epoxy resin. Since the biphenyl aralkyl type epoxy resin exhibits high compatibility with an organic polymer such as an acrylic resin, a liquid ink excellent in dispersion stability can be obtained by using a biphenyl aralkyl type epoxy resin.

The liquid ink of the present invention can be used to form a cured film which is coated with a liquid ink on a polyimide film substrate and hardens the applied liquid ink to enhance the poly A rigid cured film of an amine film substrate.

Further, the liquid ink of the present invention can be used for forming a cured film obtained by applying a liquid ink onto a flexible printed wiring board and coating the same. The liquid ink is hardened to improve the rigidity of the flexible printed wiring board.

According to the present invention, there is provided a liquid ink which is capable of improving the rigidity of an arbitrary portion which does not require bending properties while maintaining a good bending property for a substrate having flexibility such as a flexible printed wiring board.

The cured film formed by the liquid ink of the present invention exhibits good adhesion to the polyimide film. Therefore, by applying a liquid ink to a portion of the flexible printed wiring board having a polyimide film substrate as a substrate, which does not require flexibility, the cured film can be formed, and the reflow-resistant property can be prevented from being lowered. The rigidity of the flexible wiring board in which the portion having the cured film is formed is increased to have rigidity. That is, a rigid-flexible printed wiring board having a rigid portion and a flexible portion can be manufactured by a simple procedure. The rigid-flexible printed wiring board can contribute to weight reduction of various electronic devices.

Further, since the cured film formed by the liquid ink of the present invention has high reflow resistance, it is easy to achieve a high level of reflow resistance required when a lead-free solder is used.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

FIG. 1 is a cross-sectional view showing an embodiment in a state in which the cured film 1 is placed in contact with the substrate 10. The substrate 10 is a flexible substrate having flexibility such as a polyimide film. In the portion in contact with the cured film 1, the rigidity of the substrate 10 is improved as compared with when the cured film 1 is not formed. In other words, the self-supporting property of the substrate 10 is improved in the portion in contact with the cured film 1. When the substrate 10 is In the case of a flexible printed wiring board, the base material 10 in a portion in contact with the cured film 1 functions as a rigid portion of the rigid-flexible wiring board, for example.

The liquid ink of this embodiment can be used to form the cured film 1. For example, the liquid ink is applied onto the substrate 10, and the applied liquid ink is cured, whereby the cured film 1 is formed. The thickness of the cured film 1 is 50 μm to 300 μm, 80 μm to 200 μm, or 100 μm to 150 μm.

The liquid ink of the present embodiment includes a thermosetting resin composition containing an organic polymer as a polymer material, a thermosetting resin, and an inorganic filler, and a solvent which dissolves or disperses the thermosetting resin composition.

When the thermosetting resin composition in the liquid ink is cured by heating, for example, a cured product having a storage elastic modulus of 500 MPa or less and a tensile elastic modulus of 0.5 GPa to 3.0 GPa at 25 ° C is formed (for example, , hardened film 1).

The storage elastic modulus of the cured product at 25 ° C was measured by measuring the dynamic viscoelasticity of the film-like cured product. More specifically, the storage elastic modulus of the cured product at 25 ° C can be obtained by the following method: according to the stretching mode, the distance between the chucks is 20 mm, the period is 10 Hz, and the temperature is raised. A viscoelastic curve showing the relationship between the storage elastic modulus and temperature obtained by measuring the dynamic viscoelasticity of a film-like cured product having a width of 5 mm and a length of 30 mm at 5 ° C/min, read at 25 ° C Storage elastic modulus. The cured product as the measurement sample is formed, for example, by drying a coating film of a liquid ink having a thickness of 125 μm at 110 ° C for 10 minutes, and then heating at 185 ° C for 30 minutes. Make it harden.

The tensile modulus of elasticity is an initial modulus of elasticity in which a band-shaped cured product is prepared as a measurement sample, and a stress-displacement curve obtained when tensile stress is applied thereto at a tensile speed of 50 mm/min ( The initial elastic modulus obtained by the maximum value of the inclination of the tangent of the elastically deformed portion). The tensile test is usually carried out in an environment of about 23 °C.

The tensile elastic modulus of the cured product of the thermosetting resin composition of the present embodiment mainly varies depending on the content ratio of the inorganic filler having a high elastic modulus. In the thermosetting resin composition containing an organic polymer, a thermosetting resin, and an inorganic filler, when the content of the inorganic filler is 50% by mass or more based on the mass of the thermosetting resin composition, it is formed to have 0.5. GPa~3.0 GPa is highly likely to have a cured modulus of tensile modulus. The tensile elastic modulus of the cured product of the liquid ink is in the range of 0.5 GPa to 3.0 GPa, and when the substrate is bent together with the cured film, cracks are less likely to occur in the cured film. That is, the cured film 1 can be formed while maintaining the high flexibility of the substrate 10. From the same viewpoint, the cured product of the liquid ink material may have a tensile elastic modulus of 0.7 GPa to 2.0 GPa.

On the other hand, the cured elastic modulus of the cured product of the thermosetting resin composition of the present embodiment is different from the tensile elastic modulus, and is not affected by the inorganic filler, but is maintained at a low elastic modulus mainly reflecting the resin component. The lower value of the number. Specifically, the storage elastic modulus of the cured product at 25 ° C may be 500 MPa or less, or 120 MPa or less. The storage modulus of the cured product is low, and particularly excellent bending properties and reflow resistance are achieved. The lower limit of the storage elastic modulus is usually about 10 MPa, and may be 25 MPa.

A thermosetting tree for forming a cured film having the characteristics as described above Suitable embodiments of the lipid composition will be described in detail below.

As described above, the thermosetting resin composition of the present embodiment may contain 50% by mass or more based on the total solid content of the thermosetting resin composition (component other than the solvent among the liquid ink). Inorganic filler. The content ratio of the inorganic filler may be 70% by mass or more. The content ratio of the inorganic filler may be 90% by mass or less or 80% by mass or less from the viewpoint of the tensile modulus of elasticity.

The inorganic filler may contain one type of particles, or may contain a combination of two or more types of particles. The inorganic filler may have an average particle diameter of 1 μm to 100 μm, 1 μm to 50 μm, 1 μm to 20 μm, or 1.5 μm to 10 μm. The inorganic filler may also be a mixture of a plurality of fillers having different average particle diameters. Thereby, the space filling rate by the inorganic filler can be improved.

The inorganic filler may be cerium oxide particles. The cerium oxide particles may be, for example, spherical cerium oxide obtained by a sol-gel method, crushed cerium oxide finely pulverized by pulverization, dry cerium oxide or wet cerium oxide.

Examples of commercially available products of spherical cerium oxide include MSR-2212, MSR-SC3, MSR-SC4, MSR-3512, and MSR-FC208 (above, trade names manufactured by Longsen Co., Ltd.), Excelica (Germany) (trade name manufactured by Tokuyama Co., Ltd.), SO-E1, SO-E2, SO-E3, SO-E5, SO-E6, SO-C1, SO-C2, SC-C3, SO-C5, SO -C6, (above, the trade name of Admatechs Co., Ltd.), etc. As a commercial product of the crushed cerium oxide, there are listed: Crystalite 3K-S, NX-7, MCC-4, CMC-12, A1, AA, CMC-1, VX-S2, VX-SR (above, Ronson) The name of the product manufactured by the company, F05, F05-30, F05-12 (above, the name of the product manufactured by Fukushima Kiln Co., Ltd.). Dry cerium oxide such as Reolosil, wet cerium oxide such as Tokusil or Finesil (trade name manufactured by Tokuyama Co., Ltd.) can also be used.

The cerium oxide particles can be surface treated by a decane coupling agent. Thereby, precipitation of the cerium oxide particles is suppressed, and a liquid ink having higher dispersion stability can be obtained.

The decane coupling agent as a surface treatment agent for surface treatment of cerium oxide particles is, for example, selected from the group consisting of vinyl trimethoxy decane, vinyl triethoxy decane, 2-(3, 4-epoxycyclohexyl)ethyltrimethoxydecane, 3-glycidoxy propyltrimethoxysilane, 3-glycidoxypropyltrimethoxydecane, 3 - glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropylmethyldiethoxydecane, 3-glycidoxypropyltriethoxydecane, p-styryltrimethyl Oxydecane, 3-methacryloxypropylmethyldimethoxydecane, 3-methylpropenyloxypropyltrimethoxydecane, 3-methylpropenyloxypropylmethyldi Ethoxy decane, 3-methacryloxypropyltriethoxydecane, 3-propenyloxypropyltrimethoxydecane, n-(aminoethyl)-3-aminopropyl Methyldimethoxydecane N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane riethoxysilane, n-(aminoethyl)-3-aminopropyltrimethoxydecane, n-(aminoethyl)- 3-Aminopropyltriethoxydecane, 3-aminopropyltrimethoxydecane, 3-aminopropyltriethoxydecane, 3-triethoxyindolyl-N-(1,3 - dimethyl-butylene) propylamine, N-phenyl-3-aminopropyltrimethoxydecane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxy Hydrazine hydrochloride, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxydecane, 3-mercaptopropyltrimethoxydecane (3-mercaptopropyl) Methyl dimethoxy silane), bis(triethoxysilylpropyl)tetrasulfide, polyisomer of 3-isocyanate propyl triethoxy decane, dimethyl decane, diphenyl A polycondensate of decane and a copolymer condensate of dimethyl decane and diphenyl decane. Among these, a decane coupling agent having an amine group can be selected.

The organic polymer constituting the thermosetting resin composition may be an acrylic resin or a polyamideimide resin from the viewpoint of adhesion to a polyimide film substrate and heat resistance.

The polyamidoximine resin may have a siloxane group and/or an aliphatic group in addition to the guanamine group and the quinone group. The polyamidoquinone imide resin may have a weight average molecular weight of 10,000 to 150,000, 30,000 to 100,000, or 50,000 to 80,000. In the present specification, the weight average molecular weight is a standard polystyrene equivalent value determined by gel permeation chromatography (GPC).

The acrylic resin is usually a copolymer containing a polymerizable monomer containing two or more kinds of acrylic monomers. Acrylic resin can be made to have a wide range of properties by combining a plurality of commercially available acrylic monomers, and can be produced at low cost. In addition, since the acrylic resin has good solubility to a low-boiling ketone solvent, it can be easily applied to the printed liquid ink. It is also excellent in terms of drying.

The acrylic monomer constituting the acrylic resin is not particularly limited, and is, for example, one or two or more monomers selected from the group consisting of acrylonitrile, methyl acrylate, ethyl acrylate, n-propyl acrylate, and isopropyl acrylate. , n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, octadecyl acrylate, butyl acrylate Oxyethyl ester, phenyl acrylate, benzyl acrylate, naphthyl acrylate, cyclohexyl acrylate, isobornyl acrylatenor, norbornyl methyl acrylate, tricyclic acrylate [5.2.1.0 ^2,6 ]癸-8-yl ester (dicyclopentanyl acrylate), tricyclo[5.1.02 ^2,6 ]indole-4-methyl, adamantyl acrylate, isodecyl acrylate, decyl acrylate , acrylate such as tricyclohexyl acrylate [5.2.1.0 ^2,6 ] 癸-8-yl ester, tricyclohexyl acrylate [5.2.1.0 ^2,6 ] 癸-4-methyl ester, and adamantyl acrylate, and Ethyl methacrylate, methacrylic acid propylene , isopropyl methacrylate, n-butyl methacrylate (butyl methacrylate), isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, n-hexyl methacrylate, A 2-ethylhexyl acrylate, n-octyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, butoxyethyl methacrylate, phenyl methacrylate, and naphthalene methacrylate Ester such as cyclopentyl methacrylate, cyclohexyl methacrylate, methylcyclohexyl methacrylate, tricyclohexyl methacrylate, norbornyl methacrylate, methyl methacrylate, A Isodecyl acrylate, decyl methacrylate, menthyl methacrylate, adamantyl methacrylate, tricyclo[5.2.1.0 ^2,6 ] 癸-8-yl methacrylate (bicyclo methacrylate) Amyl phthalate), and methacrylate such as tricyclo[5.2.1.0 ^2,6 ] 癸-4-methyl methacrylate.

The acrylic monomer constituting the acrylic resin may further contain a functional group-containing monomer having a carboxyl group selected from the viewpoints of heat resistance and adhesion of the cured film formed of the liquid ink. At least one functional group in the group consisting of a hydroxyl group, an acid anhydride group, an amine group, a guanamine group, and an epoxy group, and at least one (meth) acrylonitrile group. The functional group-containing monomer is, for example, selected from the group consisting of a carboxyl group-containing monomer such as acrylic acid, methacrylic acid, and itaconic acid, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate. Ester, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, N-methylol methacrylamide, and hydroxyl group-containing monomers such as (o-, m-, p-) hydroxystyrene, An acid anhydride group-containing monomer such as a maleic anhydride, an amine group-containing monomer such as diethylaminoethyl acrylate or diethylaminoethyl methacrylate, and a glycidyl acrylate; glycidyl methacrylate (glycidyl methacrylate), α- ethyl acrylate (glycidyl α -ethyl acrylate), α- propyl glycidyl methacrylate (glycidyl α -n-propyl acrylate) , acrylic -3, 4-epoxybutyl butyl ester, 3,4-epoxybutyl methacrylate, 4,5-epoxy pentyl acrylate, -6,7-epoxyheptyl acrylate, methacrylic acid- 6,7-epoxyheptyl ester, 3-methyl-4-epoxybutyl acrylate, 3-methyl-3,4-epoxybutyl methacrylate, propylene 4-methyl-4,5-epoxypentyl pentyl ester, 4-methyl-4,5-epoxypentyl methacrylate, 5-methyl-5,6-epoxy acrylate Ester, β-methyl glycidyl acrylate, β-methyl glycidyl methacrylate, β-methyl glycidyl α-ethyl acrylate, 3-methyl-3,4-cyclo acrylate Oxybutyl butyl ester, 3-methyl-3,4-epoxybutyl methacrylate, 4-methyl-4,5-epoxypentyl acrylate, 4-methyl methacrylate 4,5-epoxypentyl ester, 5-methyl acrylate, 6-epoxy hexyl acrylate and 5-methyl-5,6-epoxy hexyl methacrylate Monomer. These may be used alone or in combination of two or more.

The acrylic resin may further contain other monomers copolymerized with the acrylic monomer. The other monomer is, for example, at least one compound selected from the group consisting of 4-vinylpyridine, 2-vinylpyridine, α-methylstyrene, α-ethylstyrene, α-fluoro Aromatic compounds such as styrene ( α- fluoro-styrene), α-chlorostyrene, α-bromostyrene, fluorostyrene, chlorostyrene, bromostyrene, methylstyrene, methoxystyrene, and styrene Vinyl compound, and N-methyl maleimide, N-ethyl maleimide, N-propyl maleimide, N-iso Propyl maleimide, N-butyl maleimide, N-isobutyl maleimide, N-tert-butyl maleimide, N-lauryl butene N-substituted groups such as N-lauryl maleimide, N-cyclohexylmethyleneimine, N-benzyl maleimide, and N-phenyl maleimide Maleic acid imines.

In particular, when the thermosetting resin is an epoxy resin, the acrylic resin may have a glycidyl group. By having a glycidyl group in the acrylic resin, the heat resistance of the cured film can be further improved. Therefore, the acrylic resin may also contain, as a monomer unit, glycidyl methacrylate or glycidyl acrylate as a functional group-containing monomer. To form all polymerizable sheets of acrylic resin The content of the glycidyl methacrylate may be 0.5% by mass to 10% by mass, 1% by mass to 8% by mass, or 2% by mass to 5% by mass based on the amount of the body.

The acrylic resin may contain an alkyl acrylate as a monomer unit from the viewpoint of adhesion to a flexible wiring board when the cured film is formed. The alkyl group of the alkyl acrylate may have a carbon number of 1 to 12 or 2 to 10. The content ratio of the alkyl acrylate may be 50% by mass to 99% by mass, 60% by mass to 98% by mass, or 70% by mass to 96% by mass based on the amount of all the polymerizable monomers constituting the acrylic resin. The alkyl acrylate is, for example, selected from the group consisting of ethyl acrylate and butyl acrylate.

The acrylic resin may also contain acrylonitrile or methacrylonitrile as a monomer from the viewpoint of toughness and adhesion. The content ratio of acrylonitrile or methacrylonitrile may be 0.5% by mass to 10% by mass, 1% by mass to 8% by mass, or 2% by mass to 5% by mass based on the amount of all the polymerizable monomers constituting the acrylic resin. %.

The acrylic resin is, for example, a copolymer of glycidyl methacrylate and an alkyl (meth)acrylate, a glycidyl methacrylate, a copolymer of an alkyl (meth)acrylate and (meth)acrylonitrile, A copolymer of glycidyl acrylate, alkyl (meth) acrylate and dicyclopentyl (meth) acrylate.

The weight average molecular weight of the acrylic resin may range from 400,000 to 1.8 million, 500,000 to 1.5 million, or 800,000 to 1.4 million. When the weight average molecular weight is less than 400,000, the viscosity of the liquid ink is low, and thus the dispersion stability of the inorganic filler may be lowered or the liquid ink may not exhibit thixotropy. In addition, if propylene When the weight average molecular weight of the acid resin is low, the cured film tends to be brittle and the bendability of the cured film tends to decrease. When the weight average molecular weight of the acrylic resin exceeds 1.8 million, the solubility in a solvent is remarkably lowered, and it is difficult to increase the concentration of a solid component in the liquid ink. When the concentration of the solid content of the liquid ink is low, it is considered that the control of the film thickness of the applied liquid ink and the necessity of film reduction due to drying shrinkage are improved.

The glass transition temperature (Tg) of the acrylic resin may be -50 ° C to 100 ° C, -45 ° C to 20 ° C, or -40 ° C to 5 ° C. By the glass transition temperature of the acrylic resin being within these numerical ranges, the viscosity of the cured film can be suppressed, and the storage elastic modulus and the tensile elastic modulus of the cured film can be easily controlled. The Tg of the acrylic resin can be measured by differential scanning calorimetry (DSC), and the Tg of the acrylic resin containing n kinds of monomers can also be calculated by the following calculation formula (FOX formula).

Tg(°C)={1/(W ₁ /Tg ₁ +W ₂ /Tg ₂ +...+W _i /Tg _i +...+W _n /Tg _n )}-273

In the above FOX formula, Tg _i (K) represents the glass transition temperature of the homopolymer of each monomer, and W _i represents the mass fraction of each monomer, W _i + W ₂ + ... + W _i + ... W _n = 1.

For example, a glass transition temperature (Tg) of an acrylic resin obtained by copolymerizing a ratio of 5% by mass of glycidyl methacrylate, 5% by mass of acrylonitrile, 85% by mass of ethyl acrylate, and 5% by mass of butyl acrylate is as Calculated as follows.

Tg={1/(0.05/319+0.05/498+0.85/251+0.05/219)}-273=-14.7°C

The thermosetting resin constituting the thermosetting resin composition is a compound having a curable functional group (for example, an epoxy group). The thermosetting resin is, for example, selected from the group consisting of epoxy resins, polyimine resins, polyamidoximine resins, triazine resins, phenol resins, melamine resins, polyester resins, cyanate resins, and the like. One or two or more of the modified systems of some resins.

The thermosetting resin can also contain a high molecular weight component for the purpose of improving the flexibility and heat resistance of the cured film. However, the molecular weight of the thermosetting resin is usually 3,000 or less.

The epoxy resin is, for example, one or more selected from the group consisting of polyphenols such as bisphenol A, novolac type phenol resin, and o-cresol novolak type phenol resin, or 1,4-butanediol. A polyglycidyl ether obtained by reacting a polyhydric alcohol with epichlorohydrin, a polyglycidyl ester obtained by reacting a polybasic acid such as phthalic acid or hexahydrophthalic acid with epichlorohydrin, having an amine group and an anthracene group. An N-glycidyl derivative of an amine or heterocyclic nitrogenous base-containing compound, and an alicyclic epoxy resin. Among these, a polyglycidyl ether selected from a biphenyl aralkyl type epoxy resin and a naphthalene type tetrafunctional epoxy resin, and an N-shrinkage of a compound having a guanamine group or a heterocyclic nitrogen group-containing compound Glyceryl derivatives have high compatibility with organic polymers, especially acrylic resins.

Examples of the phenol resin include a phenol type, a bisphenol A type, a cresol novolak type, and an aminotriazine novolak type phenol resin. Just with acrylic trees From the viewpoint of the compatibility of the fat, one or both of a cresol novolac type and an aminotriazine novolak type phenol resin may be selected. The amine triazine novolac type phenol resin has a structural unit represented by the following structural formula (1). When a phenol resin is combined with an epoxy resin, it may function as a hardener of an epoxy resin.

In the formula (1), R represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 30].

The thermosetting resin composition may also contain a curing agent which is generally used to cure the thermosetting resin. For example, when the thermosetting resin is an epoxy resin, the hardener may be selected from the group consisting of dicyandiamide, diaminodiphenylmethane, diaminodiphenylphosphonium, phthalic anhydride, and pyromellitic anhydride. And polyfunctional phenols such as phenol novolac and cresol novolac.

In order to promote the reaction of a thermosetting resin and a hardener, etc., an accelerator is often used. The type and amount of the accelerator are not particularly limited. For example, an imidazole compound, an organophosphorus compound, a tertiary amine, or a quaternary ammonium salt may be used, or two or more kinds thereof may be used in combination.

The total mass of the organic polymer (such as an acrylic resin), a thermosetting resin (such as an epoxy resin), and a curing agent (such as a phenol resin) (may correspond to the total amount of components other than the inorganic filler of the thermosetting resin composition. Quality) The content ratio of the organic polymer may be 40% by mass to 90% by mass, 50% by mass to 85% by mass, or 60% by mass to 80% by mass. The total of the epoxy groups of the glycidyl group of the acrylic resin and the epoxy resin and the amount of the hydroxyl group of the phenol resin may be substantially equivalent. The ratio of the thermosetting resin to the curing agent is appropriately set in the range generally employed in consideration of such reactivity and the like.

As the solvent constituting the liquid ink, for example, a ketone solvent such as methyl ethyl ketone or cyclohexanone can be used. From the standpoint of printability, cyclohexanone can be selected. The concentration of the thermosetting resin composition (component other than the solvent) in the liquid ink may be 40% by mass to 70% by mass based on the mass of the liquid ink.

The liquid ink can be prepared by mixing the components constituting the thermosetting resin composition with a solvent and stirring as necessary. The inorganic filler may be slurried by dispersing in advance in an organic solvent containing a surface treatment agent. The solid content concentration (concentration of the inorganic filler) of the slurry containing the inorganic filler and the solvent is not particularly limited, but may be 50% by mass to 90% by mass, 60% by mass to 80% by mass based on the mass of the slurry, Or 65 mass% to 75% by mass. A mixture of an organic polymer, a thermosetting resin, and a curing agent may also be prepared in advance. The mixture may be mixed with a slurry of an inorganic filler to obtain a liquid ink.

In order to form a cured film, the liquid ink of this embodiment is applied to a predetermined portion of the substrate. The coating method may be, for example, continuous coating such as bar coating, comma coating, or roll coating, or may be a printing method such as screen printing or metal mask printing.

The applied liquid ink (coating film) is dried as needed, and then hardened. The drying temperature can be 50 ° C ~ 150 ° C, 80 ° C ~ 130 ° C, or 100 ° C ~ 120 ° C. The coating film is hardened by further treatment at a high temperature. hardening The temperature can be 150 ° C ~ 250 ° C, 160 ° C ~ 200 ° C, or 180 ° C ~ 190 ° C.

Instance

Hereinafter, the present invention will be described more specifically by way of examples. However, the invention is not limited to the examples.

Example 1

7 g of N-phenyl-3-aminopropyltrimethoxydecane (KBM573, trade name, manufactured by Shintosu Silicon Co., Ltd.) as a surface treatment agent was dissolved in methyl ethyl ketone 300 g In the meantime, 700 g of F05-12 (trade name, manufactured by Fukushima Kiln Co., Ltd.) as crushed cerium oxide was added thereto while stirring, and then further stirred at room temperature for 1 hour. The agglomerated portion of the crushed cerium oxide was filtered off using a 200-mesh nylon cloth to obtain a slurry-like filtrate (cerium oxide slurry). Methyl ethyl ketone (Methyl) which is a copolymer of glycidyl methacrylate, ethyl acrylate and butyl acrylate (weight average molecular weight: 1.3 million, epoxy equivalent of 7800, Tg of -45 ° C) Ethyl Ketone, MEK) solution (concentration: 20% by mass) 350 g, biphenyl aralkyl type epoxy resin (NC-3000H, trade name manufactured by Nippon Kayaku Co., Ltd.) MEK solution (concentration: 50% by mass) 34.2 g, MEK solution (concentration: 50% by mass) of phenol resin (LA-3018, trade name manufactured by Dainippon Ink Co., Ltd.) 25.8 g, and 1-cyanoethyl-2-phenylimidazole (2PZ) -CN, trade name manufactured by Shikoku Chemicals Co., Ltd.) 0.5 g was mixed and stirred to obtain a resin solution. To the resin solution, 430 g of a cerium oxide slurry was added and stirred for 1 hour to obtain a liquid ink.

Example 2 to Example 11, Reference Example 1 to Reference Example 4, and Comparative Example 5 to Comparative Example 8

A liquid ink was prepared in the same manner as in Example 1 except that each of the materials shown in Tables 1 and 2 was used in the formulation ratio shown in the table. The blending ratio of the organic polymer, the thermosetting resin, and the curing agent is a blending ratio based on the mass of the thermosetting resin composition other than the inorganic filler, and the blending ratio of the inorganic filler is the total solid of the thermosetting resin composition. The mass ratio of the components (components other than the solvent among the liquid inks) is a reference ratio.

Example 12

7 g of N-phenyl-3-aminopropyltrimethoxydecane (KBM573, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface treatment agent was dissolved in 300 g of cyclohexanone while stirring. 700 g of SO-25R (trade name, manufactured by Admatech Co., Ltd.) as spherical cerium oxide was added thereto, and further stirred at room temperature for 1 hour. The agglomerated portion of the spherical cerium oxide was filtered off using a 200-mesh nylon cloth to obtain a slurry-like filtrate (cerium oxide slurry). a cyclohexanone solution (concentration of 20% by mass) of a copolymer of glycidyl methacrylate, acrylonitrile, ethyl acrylate and butyl acrylate (weight average molecular weight: 450,000, Tg -14.7 ° C) as an acrylic resin 350 g, biphenyl aralkyl type epoxy resin (NC-3000H, trade name manufactured by Nippon Kayaku Co., Ltd.) cyclohexanone solution (concentration: 50% by mass) 34.2 g, phenol resin (LA-3018 , propylene glycol monomethyl ether solution (concentration: 50% by mass) 25.8 g, and 1-cyanoethyl-2-phenylimidazole (2PZ-CN, Shikoku Chemicals Co., Ltd.) Limited company The obtained product name was mixed with 0.5 g, and stirred to obtain a resin solution. To the resin solution, 430 g of the above cerium oxide slurry (concentration of the inorganic filler: 70% by mass) was added and stirred for 1 hour to obtain a liquid ink.

The details of each of the materials shown in Tables 1 and 2 are as follows.

Acrylic resin

. GMA/EA/BA: copolymer of glycidyl methacrylate, ethyl acrylate and butyl acrylate (mixing ratio of monomer: GMA/EA/BA=2/26/72 (mass ratio), Tg: -45 ° C)

. GMA/AN/EA/BA: Copolymer of glycidyl methacrylate, acrylonitrile, ethyl acrylate and butyl acrylate (mixing ratio of monomer: GMA/AN/EA/BA=5/5/85/5 (mass ratio), Tg: -14.7 ° C)

. GMA/EA/BA/FA513AS: copolymer of glycidyl methacrylate, ethyl acrylate, butyl acrylate and dicyclopentanyl acrylate (mixing ratio of monomer: GMA/EA/BA/FA513AS=5/28/ 38.5/28.5 (mass ratio), Tg: -6.7 ° C)

2. Epoxy

. NC-3000H: biphenyl aralkyl type epoxy resin (trade name, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 290)

. EXA4710: naphthalene type tetrafunctional epoxy resin (trade name, manufactured by Dainippon Ink Co., Ltd., epoxy equivalent: 170)

. N770: Phenolic novolac type epoxy resin (manufactured by Dainippon Ink Co., Ltd., epoxy equivalent: 188)

3. Phenolic resin (hardener)

. LA-3018: Aminotriazine novolac type phenol resin (Greater Japan ink The trade name of the company, with a hydroxyl equivalent of 151 and a nitrogen content of 18%)

. KA-1165: Cresol novolak type phenol resin (trade name by Dainippon Ink Co., Ltd., hydroxyl equivalent: 119)

. LA-1356: Aminotriazine novolac type phenol resin (trade name manufactured by Dainippon Ink Co., Ltd., hydroxyl equivalent: 146, nitrogen content: 19%)

4. cerium oxide particles

. F05-12: Broken cerium oxide, trade name manufactured by Fukushima Kiln Co., Ltd.

. F05-30: Broken cerium oxide, trade name manufactured by Fukushima Kiln Co., Ltd.

. SO-C6/SO-E3: Spherical cerium oxide, trade name manufactured by Admatechs Co., Ltd.

. SO-25R: Spherical cerium oxide, trade name manufactured by Admatechs Co., Ltd.

5. Surface treatment agent (decane coupling agent)

. KBM573: N-phenyl-3-aminopropyltrimethoxydecane, trade name manufactured by Shin-Etsu Lee Co., Ltd.

. KBM602: N-2-(Aminoethyl)-3-aminopropylmethyldimethoxydecane, trade name manufactured by Shin-Etsu Lee Co., Ltd.

. KBM903: 3-aminopropyltrimethoxydecane, trade name manufactured by Shin-Etsu Lee Co., Ltd.

. KBM5103: 3-propenyloxypropyltrimethoxydecane, Shin-Etsu Trade name manufactured by Lee Co., Ltd.

. DMDS/TEMOS: polyoxyalkylene oligomers formed from Dimethyldimethoxysilane (DMDS) and Tetramethoxysilane (TEMOS)

(Evaluation)

1. Adhesion to polyimine film

The liquid ink was applied onto a polyimide film (Upilex 50S) by a bar coater so that the thickness after drying became 125 μm. The applied liquid ink was dried by heating at 110 ° C for 10 minutes, and then cured by heating at 185 ° C for 30 minutes to form a cured film adhered to the polyimide film. The cured film was divided into a grid shape by using a cutter and 10 slits spaced at 2 mm intervals and 10 slits spaced 2 mm apart at right angles to the slits. After the adhesive tape was attached thereto, the adhesive tape was peeled off, and the adhesiveness was evaluated based on the number of the disc remaining in the polyimide film. When the number of the discs remaining on the polyimide film was large, it was judged that the adhesion to the polyimide was good.

2. Storage elastic modulus of hardened matter

A liquid ink having a thickness of 125 μm after drying was applied to a release-treated polyethylene terephthalate (PET) film using a bar coater. The applied liquid ink was dried by heating at 110 ° C for 10 minutes, and then cured by heating at 185 ° C for 30 minutes to form a cured film (cured product). A sample having a width of 5 mm and a length of 30 mm was punched out from the cured product peeled off from the release film. For the sample, a viscoelasticity measurement was performed using a dynamic viscoelasticity measuring apparatus (REOGEL4000 manufactured by Rheology Co., Ltd.) with a distance between the chucks of 20 mm, a cycle of 10 Hz, and a temperature increase rate of 5 °C/min. Based on the obtained viscoelastic curve, the storage elastic modulus and Tg at 25 ° C were determined.

3. Mechanical properties of the hardened material

A liquid ink having a thickness of 125 μm after drying was applied to a release-treated PET (polyethylene terephthalate) film using a bar coater. The applied liquid ink was dried by heating at 110 ° C for 10 minutes, and then cured by heating at 185 ° C for 30 minutes to form a cured film (cured product). A sample having a width of 10 mm and a length of 100 mm was punched out from the cured product peeled off from the release film. For this sample, a tensile test was performed using an EZ tester at a tensile speed of 50 mm/min to obtain a stress-displacement curve. The maximum value of the inclination of the tangent of the stress-displacement curve at the initial stage of the rise, and the tensile elastic modulus was obtained from the following formula. The stress-displacement curve of the cured product of the liquid ink obtained in Example 11 is shown in Fig. 2 . The tensile elastic modulus is calculated from the inclination of the tangent T having the largest inclination among the tangent of the stress-displacement curve of Fig. 2 .

Tensile modulus of elasticity (Pa) = maximum value of the inclination of the tangent of the stress-displacement curve (N/m) × [displacement (m) / sectional area of the cured product (m ² )]

4. Self-support

A liquid ink having a thickness of 125 μm after drying was applied to a polyimide film (Upilex 50S) using a bar coater. The applied liquid ink was dried by heating at 110 ° C for 10 minutes, and then cured by heating at 185 ° C for 30 minutes to form a cured film (cured product). The cured film was punched together with a polyimide film to a size of 10 mm in width and 100 mm in length to obtain a sample. Open 80 mm On the two stages provided at intervals, the obtained sample was placed so as to straddle the stages, and the amount of sinking of the central portion of the sample at this time was measured. When the sinking amount is 10 mm or less, it is judged to be self-supporting.

5. Bending

A 0.3 mm needle gauge was attached to a sample containing a polyimide film and a cured film laminated thereon, and the sample was wound around a needle gauge while being bent to about 180 degrees. There are no cracks at this time. The polyimide film was placed on the outer side or the inner side with respect to the needle gauge, and the same evaluation was performed. When the occurrence of cracks was not found, it was judged that the bending property was good.

6. Reflow resistance

A sample containing a polyimide film and a cured film laminated thereon was sandwiched between two wire meshes to carry out a conveyor type reflow test. That is, the sample was subjected to three treatments at a speed of 1.2 m/min by a heating temperature at which the maximum temperature of the surface of the sample was 260 ° C and the temperature was maintained for 10 seconds. After the treatment, the presence or absence of swelling and peeling between the polyimide film/hardened film was confirmed by visual appearance. When no swelling or peeling was observed, it was judged that the reflow resistance was good.

(result)

The liquid ink of the example had excellent dispersion stability, and even after standing for 2 weeks, no aggregation of cerium oxide was observed. By using the cured film formed of the liquid inks, the polyimide film can be self-supporting. In addition, the cured film has good adhesion to polyimide, and has no problem in reflow resistance. Since the liquid ink of Reference Example 1 is agglomerated by cerium oxide, there is a problem in stability. The liquid ink of Reference Example 2 and Reference Example 3 was separated by the resin, so that there was a problem in stability. The cured film formed by using the liquid ink of Comparative Example 5 could not be used. The polyimide membrane imparts self-support. The cured film formed by the liquid ink of Comparative Example 6 could not be bent together with the polyimide film without causing cracks.

The cured product formed by the liquid ink of Reference Example 4 having the composition of the cerium oxide particles removed from the liquid ink of Example 3 had a storage elastic modulus at 25 ° C which was substantially the same as that of Example 3 The value of the degree. Thereby, it was confirmed that the storage elastic modulus of the cured product at 25 ° C is a value mainly reflecting the elastic modulus of the resin component from which the inorganic filler has been removed.

1‧‧‧ hardened film (hardened)

10‧‧‧Substrate

T‧‧‧ tangent

Fig. 1 is a cross-sectional view showing an embodiment in a state in which a cured film is placed in contact with a substrate.

2 is a stress-displacement curve of a cured product of the liquid ink obtained in Example 11 and a tangent thereof.

1‧‧‧hardened film

10‧‧‧Substrate

Claims (12)

A liquid ink comprising: a thermosetting resin composition containing an organic polymer, a thermosetting resin, and an inorganic filler; and a solvent which dissolves or disperses the thermosetting resin composition, and is composed of the above thermosetting resin When the material has hardened, a cured product having a storage elastic modulus of 500 MPa or less and a tensile elastic modulus of 0.5 GPa to 3.0 GPa at 25 ° C is formed. The liquid ink according to the first aspect of the invention, wherein the thermosetting resin composition contains 50% by mass or more of the inorganic filler based on the mass of the thermosetting resin composition. The liquid ink according to claim 1 or 2, wherein the organic polymer contains an acrylic resin. The liquid ink according to claim 3, wherein the acrylic resin has a glycidyl group. The liquid ink according to the third or fourth aspect of the invention, wherein the acrylic resin has a weight average molecular weight of 400,000 to 1.8 million. The liquid ink according to any one of claims 1 to 5, wherein the inorganic filler contains cerium oxide particles. The liquid ink according to claim 6, wherein the cerium oxide particles are surface-treated by a decane coupling agent. The liquid ink according to claim 7, wherein the decane coupling agent has an amine group. The liquid according to any one of claims 1 to 8 In the ink, the thermosetting resin contains an epoxy resin, and the thermosetting resin composition further contains a phenol resin. The liquid ink according to claim 9, wherein the epoxy resin comprises a biphenyl aralkyl type epoxy resin. The liquid ink according to any one of claims 1 to 10, which is used for forming a cured film which is applied to a polyimide film substrate by a liquid ink. And curing the above-mentioned liquid ink to improve the rigidity of the polyimide film substrate. The liquid ink according to any one of claims 1 to 10, which is used for forming a cured film which is applied to a flexible printed wiring board by a liquid ink, and A cured film that cures the liquid ink to be applied to improve the rigidity of the flexible printed wiring board.