KR102036135B1 - Liquid ink - Google Patents

Abstract

A liquid ink containing 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, the cured product 1 having a storage modulus at 25 ° C. of 500 MPa or less and a tensile modulus of 0.5 GPa to 3.0 GPa is formed.

Description

Liquid ink {LIQUID INK}

The present invention relates to a liquid ink.

Background Art Conventionally, various printed wiring boards of one side, both sides, or multiple layers have been widely used in the field of industrial equipment or consumer equipment. In an electronic device, only one printed wiring board is rarely used. For example, a plurality of printed wiring boards divided by functions are generally used. Usually, a plurality of wiring boards are connected by various connectors.

Electronic devices are aimed at light and small components, and particularly high-density mounted printed wiring boards representing light and small components are incorporated in recent mobile phones, video cameras, and notebook PCs. In such electronic devices, it is necessary to assemble a plurality of printed wiring boards compactly in a limited space. However, when the board | substrate of these wiring boards is connected by a connector, a volume will become large, and connection by a connector is already difficult. For this reason, what is called the flexible rigid wiring board which combined the flexible substrate, such as a polyimide film base material, and a rigid substrate, is proposed in various ways.

For example, the manufacturing method of the rigid flexible wiring board which thermocouple-compresses a rigid board | substrate and a flexible board | substrate through an adhesive sheet, and electrically connects the circuit of a rigid board | substrate and a flexible board | substrate through a through hole is proposed (for example, For example, refer patent document 1).

Furthermore, a rigid flexi that is partially flexible is laminated by laminating a rigid substrate having no flexibility to a flexible substrate having a flexibility, and partially forming a window portion on the rigid substrate to expose the flexible substrate. The manufacturing method of a board | substrate is proposed (for example, refer patent document 2).

Moreover, it is proposed to give rigidity partially by thickening the thickness of the conductor part of a printed wiring board (for example, refer patent document 3).

Patent Document 1: Japanese Patent Application Laid-Open No. 2-39594 Patent Document 2: Japanese Patent Application Laid-Open No. 5-90756 Patent Document 3: Japanese Patent Publication No. 2006-352103

The main object of this invention is to provide the liquid ink which can raise the rigidity of arbitrary parts which do not require bendability, maintaining favorable bendability with respect to the base material which has bendability, such as a flexible printed wiring board.

The present invention relates to a liquid ink containing 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 modulus at 25 ° C. of 500 MPa or less and a tensile modulus of 0.5 GPa to 3.0 GPa may be formed.

According to the liquid ink which concerns on the said invention, since the hardened | cured material of the thermosetting resin composition to which the inorganic filler was applied has the said specific storage elastic modulus and tensile elasticity modulus, it is favorable bendability with respect to the base material which has flexibility, such as a flexible printed wiring board. It is possible to increase the rigidity of any part that does not require bendability while maintaining.

The thermosetting resin composition may contain 50 mass% or more of inorganic fillers based on the mass of the total solid (components other than a solvent in a liquid ink) of a thermosetting resin composition. In addition, the organic polymer may contain the acrylic resin. Thereby, the thermosetting resin which forms the hardened | cured material which has the said specific storage elastic modulus and tensile elasticity modulus is comprised especially easily.

Acrylic resin may have glycidyl group. The weight average molecular weight of an acrylic resin may be 400,000-1,800,000, 500,000-1,500,000, or 800,000-1,400,000.

The inorganic filler may contain the silica particle. The silica particles may be surface treated with a silane coupling agent. Thereby, sedimentation of a silica particle is suppressed and a liquid ink with higher stability can be obtained. From the same viewpoint, the silane coupling agent may have an amino group.

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

The epoxy resin may contain the biphenyl aralkyl type epoxy resin. Since biphenyl aralkyl type epoxy resin shows high compatibility with organic polymers, such as an acrylic resin, the liquid ink which is excellent in dispersion stability can be obtained by using this.

The liquid ink which concerns on this invention can be used for apply | coating a liquid ink to a polyimide film base material, hardening | curing the applied liquid ink, and forming a cured film which raises the rigidity of a polyimide film base material.

Moreover, the liquid ink which concerns on this invention can be used for apply | coating liquid ink to a flexible printed wiring board, hardening | curing the applied liquid ink, and forming a cured film which raises the rigidity of a flexible printed wiring board.

ADVANTAGE OF THE INVENTION According to this invention, the liquid ink which can raise the rigidity of the arbitrary part which does not need bendability, maintaining favorable bendability with respect to the base material which has bendability, such as a flexible printed wiring board, is provided.

The cured film formed with the liquid ink which concerns on this invention shows favorable adhesiveness with respect to a polyimide film. Therefore, by applying liquid ink to a portion which does not require the flexibility of the flexible printed wiring board having the polyimide film base material as a substrate, the cured film is formed while avoiding the deterioration of the reflow property. It is possible to raise and to have rigidity. That is, a rigid-flexible printed wiring board which has a rigid part and a flexible part can be manufactured by a simple process. Such a rigid-flexible printed wiring board can contribute to the weight reduction of various electronic devices.

Moreover, since the cured film formed by the liquid ink which concerns on this invention has high reflow property, the high level of reflow property required when using a lead-free solder is easily achieved.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the state in which the cured film was installed in contact with a base material.
Fig. 2 is a stress-displacement curve of the cured product of the liquid ink obtained in Example 11 and its tangent line.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described in detail. However, this invention is not limited to the following embodiment.

FIG. 1: is sectional drawing which shows one Embodiment of the state in which the cured film 1 was provided in contact with the base material 10. FIG. The base material 10 is a flexible base material having flexibility such as a polyimide film. The rigidity of the base material 10 is raised compared with the case where the cured film 1 is not formed in the part which contact | connects the cured film 1. In other words, the self supporting property of the base material 10 is improved in the part which contact | connects the cured film 1. When the base material 10 is a flexible printed wiring board, the base material 10 of the part which is in contact with the cured film 1 can function as a rigid part of a rigid-flexible wiring board, for example.

The liquid ink which concerns on this embodiment can be used in order to form the cured film 1. For example, the cured film 1 is formed by apply | coating liquid ink to the base material 10, and hardening the apply | coated liquid ink. The thickness of the cured film 1 is 50-300 micrometers, 80-200 micrometers, or 100-150 micrometers.

The liquid ink which concerns on this embodiment contains the thermosetting resin composition containing the organic polymer which is a polymeric material, a thermosetting resin, and an inorganic filler, and the solvent which melt | dissolves or disperse | distributes a thermosetting resin composition.

When the thermosetting resin composition in a liquid ink is hardened | cured by heating, the hardened | cured material (for example, cured film 1) whose storage elastic modulus in 25 degreeC is 500 Mpa or less, and tensile elasticity modulus is 0.5 GPa-3.0 GPa, for example. ) Is formed.

The storage elastic modulus in 25 degreeC of hardened | cured material is measured by measuring the dynamic viscoelasticity of the film-form hardened | cured material. More specifically, the storage modulus at 25 ° C. of the cured product is characterized by the dynamic viscoelasticity of the film-shaped cured product having a width of 5 mm and a length of 30 mm. It can obtain | require by the method of reading out the storage elastic modulus in 25 degreeC from the viscoelastic curve which shows the relationship between storage elastic modulus and temperature obtained by measuring on conditions. The hardened | cured material as a measurement sample is formed by drying the coating film of the liquid ink of 125 micrometers in thickness at 110 degreeC by heating for 10 minutes, and then hardening by heating at 185 degreeC for 30 minutes.

The tensile modulus is obtained from the maximum value of the slope of the tangent of the stress-displacement curve (elastic deformation part) obtained when a single-shaped cured product is prepared as a measurement sample and a tensile stress is applied thereto at a tensile speed of 50 mm / min. It is the initial elastic modulus obtained. Tensile tests are usually performed in an atmosphere of about 23 ° C.

The tensile elasticity modulus of the hardened | cured material of the thermosetting resin composition which concerns on this embodiment changes mainly depending on the content rate of the inorganic filler which has a high elasticity modulus. In the thermosetting resin composition containing an organic polymer, a thermosetting resin, and an inorganic filler, when the content rate of an inorganic filler is 50 mass% or more based on the mass of a thermosetting resin composition, it has a tensile elasticity modulus of 0.5 GPa-3.0 GPa. Cargo is likely to form. The tensile elasticity modulus of the hardened | cured material of a liquid ink exists in the range of 0.5 GPa-3.0 GPa, and when a base material is bent with a cured film, a crack hardly arises in a cured film. That is, the cured film 1 can be formed, maintaining the high flexibility of the base material 10. From the same viewpoint, the tensile modulus of the cured product of the liquid ink material may be 0.7 GPa to 2.0 GPa.

On the other hand, unlike the tensile elasticity modulus, the storage elastic modulus of the hardened | cured material of the thermosetting resin composition which concerns on this embodiment does not receive the influence of an inorganic filler very much, and is maintained at the comparatively low value which mainly reflected the low elastic modulus of a resin component. Specifically, the storage modulus at 25 ° C. of the cured product may be 500 MPa or less or 120 MPa or less. Due to the low storage modulus of the cured product, particularly excellent bendability and downflow properties are achieved. The minimum of this storage elastic modulus is about 10 Mpa normally, and 25 Mpa may be sufficient.

Preferred embodiment of the thermosetting resin composition which forms the cured film which has the above characteristics is demonstrated in detail below.

As explained above, the thermosetting resin composition which concerns on this embodiment may contain 50 mass% or more of inorganic fillers based on the mass of the total solid (components other than a solvent in liquid ink) of a thermosetting resin composition. 70 mass% or more of the content rate of an inorganic filler may be sufficient. 90 mass% or less or 80 mass% or less may be sufficient as the content rate of an inorganic filler from a viewpoint of a tensile elasticity modulus.

An inorganic filler may be comprised from 1 type of particle | grains, and may be comprised from the combination of 2 or more types of particle | grains. 1-100 micrometers, 1-50 micrometers, 1-20 micrometers, or 1.5-10 micrometers may be sufficient as the average particle diameter of an inorganic filler. The inorganic filler may be a mixture of plural kinds of fillers having different average particle diameters. Thereby, the space filling rate by an inorganic filler can be raised.

The inorganic filler may be silica particles. The silica particles may be, for example, spherical silica obtained by the sol gel method, crushed silica refined by grinding, dry silica or wet silica.

As a commercial item of a spherical silica, MSR-2212, MSR-SC3, MSR-SC4, MSR-3512, MSR-FC208 (above, brand name made by Longmori), Eccerica (brand name by Tokuyama Corporation), SO -E1, SO-E2, SO-E3, SO-E5, SO-E6, SO-C1, SO-C2, SO-C3, SO-C5, SO-C6, (above, made by ADMATEX Corporation ) And the like. As a commercial item of crushed silica, Crystallite 3K-S, NX-7, MCC-4, CMC-12, A1, AA, CMC-1, VX-S2, VX-SR (above, product name of Rongmori) , F05, F05-30, F05-12 (above, Fukushima Yogyo Co., Ltd. brand name) etc. are mentioned. Wet silica (above, brand name made by Tokuyama), such as dry silica, a tokusil, and a fine thread, such as a leorosil, can also be used.

The silica particles may be surface treated with a silane coupling agent. Thereby, sedimentation of a silica particle is suppressed and the liquid ink with higher dispersion stability can be obtained.

The silane coupling agent as the surface treatment agent used for surface treatment of silica particles is, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Triethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-metha Krilloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, n-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, ethoxysilane, n-2- (aminoethyl) -3- Aminopropyltrimethoxysilane, n-2- (aminoethyl) -3-aminopropyltriethoxy Silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-amino Propyltrimethoxysilane, hydrochloride of N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, 3-ureapropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3 Mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, polycondensates of dimethylsilane, polycondensates of diphenylsilane, and dimethylsilane and diphenylsilane Is selected from the group consisting of co-condensates. Among these, the silane coupling agent which has an amino group can be selected.

The acrylic polymer or polyamide-imide resin may be sufficient as the organic polymer which comprises a thermosetting resin composition from a viewpoint of adhesiveness with a polyimide film base material, heat resistance, etc.

The polyamideimide resin may have a siloxane group and / or an aliphatic group in addition to an amide group and an imide group. The weight average molecular weight of polyamide-imide resin may be 10000-150000, 30000-100000, or 50000-80000. In this specification, a weight average molecular weight is a standard polystyrene conversion value calculated | required by GPC measurement.

An acrylic resin is generally a copolymer comprised from the polymerizable monomer containing 2 or more types of acrylic monomers. By combining various commercially available acrylic monomers, the acrylic resin can be matched with its properties in a wide range, and can be produced at low cost. Moreover, since an acrylic resin has favorable solubility with respect to a low boiling point ketone solvent, it is also excellent in the point that a printed liquid ink can be dried easily.

Although the acrylic monomer which comprises an acrylic resin is not specifically limited, For example, acrylonitrile, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-acrylate Butyl, pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, octadecyl acrylate, butoxy ethyl acrylate, phenyl acrylate, benzyl acrylate, naphthyl acrylate, cyclohexyl acrylate, acrylic acid Isobonyl, norbornylmethyl acrylate, tricyclo [5.2.1.O ^2,6 ] deca-8-yl (dicyclopentanylacrylate), tricyclo [5.2.1.O ^2,6 ] deca -4-methyl, adamantyl acrylate, isobornyl acrylate, norbornyl acrylate, tricyclohexyl acrylate [5.2.1.O ^2,6 ] deca-8-yl, tricyclohexyl acrylate [5.2.1.O ^2,6] deca-4-methyl, and the acid-adamantyl Acrylate ester, and ethyl methacrylate (ethyl methacrylate), n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate (butyl methacrylate), i-butyl methacrylate T-butyl methacrylate, pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, butoxy methacrylate Cyclopentyl methacrylate such as ethyl, phenyl methacrylate, and naphthyl methacrylate, cyclohexyl methacrylate, methylcyclohexyl methacrylate, tricyclohexyl methacrylate, norbornyl methacrylate, methacrylic acid Norbornylmethyl, isobornyl methacrylate, boryl methacrylate, menthyl methacrylate, adamantyl methacrylate, tricyclo [5.2.1.O ^2,6 ] deca-8-yl (dic) claw fentanyl methacrylate), and methacrylate, tricyclo [5.2.1.O ^2,6] deca-4, such as methyl methacrylate Is one or two or more kinds of monomers selected from esters.

From the heat resistance and adhesiveness of the cured film formed from liquid ink, the acrylic monomer which comprises an acrylic resin is at least 1 sort (s) of functional group chosen from the group which consists of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group, and an epoxy group. And the functional group containing monomer which has at least 1 (meth) acryl group. The functional group-containing monomers are, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid and itaconic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and meta Hydroxyl group-containing monomers such as 2-hydroxypropyl methacrylate, N-metholol methacrylamide and (o-, m-, p-) hydroxystyrene, acid anhydride group-containing monomers such as maleic anhydride, acrylic acid di Amino group-containing monomers such as ethylaminoethyl and diethylaminoethyl methacrylate, glycidyl acrylate, glycidyl methacrylate (glycidyl methacrylate), α-ethyl acrylate glycidyl and α-n- Glycidyl acrylate, 3,4-epoxybutyl acrylate, methacrylic acid-3,4-epoxybutyl, acrylic acid-4,5-epoxypentyl, acrylic acid-6,7-epoxyheptyl, methacrylic acid-6, 7-epoxyheptyl, -3-methyl-4-epoxybutyl acrylate, -3-methyl-3,4-epoxy methacrylate Cibutyl, acrylic acid-4-methyl-4,5-epoxypentyl, methacrylate-4-methyl-4,5-epoxypentyl, acrylic acid-5-methyl-5,6-epoxyhexyl, acrylic acid -β-methylglycol Cydyl, methacrylic acid-β-methylglycidyl, α-ethylacrylic acid-β-methylglycidyl, acrylic acid-3-methyl-3,4-epoxybutyl, methacrylate-3-methyl-3,4 -Epoxybutyl, -4-methyl-4,5-epoxypentyl, methacrylate 4-methyl-4,5-epoxypentyl, acrylic acid-5-methyl, acrylic acid-6-epoxyhexyl and methacrylic acid-5 It is selected from the group which consists of epoxy group containing monomers, such as -methyl-5, 6- epoxyhexyl. These are used individually or in combination of 2 or more types.

Acrylic resin may further contain the other monomer copolymerized with an acryl monomer. Other monomers are, for example, 4-vinylpyridine, 2-vinylpyridine, α-methylstyrene, α-ethylstyrene, α-fluorostyrene, α-crostyrene, α-bromostyrene, fluorostyrene and chloro Aromatic vinyl compounds such as styrene, bromostyrene, methyl styrene, methoxy styrene and styrene, and N-methyl maleimide, N-ethyl maleimide, N-propyl maleimide, Ni-propyl maleimide, and N-butyl maleim Group consisting of N-substituted maleimides such as mid, Ni-butyl maleimide, Nt-butyl maleimide, N-lauryl maleimide, N-cyclohexyl maleimide, N-benzyl maleimide and N-phenyl maleimide At least one compound selected from.

Acrylic resin may have glycidyl group especially when thermosetting resin is an epoxy resin. When an acrylic resin has glycidyl group, the heat resistance of a cured film can further be improved. Therefore, acrylic resin may contain glycidyl methacrylate or glycidyl acrylate which is a functional group containing monomer as a monomer unit. 0.5-10 mass%, 1-8 mass%, or 2-5 mass% may be sufficient as the content rate of glycidyl methacrylate based on the quantity of all the polymerizable monomers which comprise an acrylic resin.

Acrylic resin may contain the alkyl acrylate as a monomer from the adhesive point with the flexible wiring board at the time of using as a cured film. 1-12 or 2-10 may be sufficient as carbon number of the alkyl group of alkylacrylate. 50-99 mass%, 60-98 mass%, or 70-96 mass% may be sufficient as the content rate of alkylacrylate based on the quantity of all the polymerizable monomers which comprise an acrylic resin. The alkyl acrylate is selected from, for example, ethyl acrylate and butyl acrylate.

Acrylic resin may contain acrylonitrile or methacrylonitrile as a monomer from a toughness and adhesive viewpoint. 0.5-10 mass%, 1-8 mass%, or 2-5 mass% may be sufficient as the content rate of acrylonitrile or methacrylonitrile based on the quantity of all the polymerizable monomers which comprise an acrylic resin.

The acrylic resin is, for example, a copolymer of glycidyl methacrylate and alkyl (meth) acrylate, a copolymer of glycidyl methacrylate, alkyl (meth) acrylate and (meth) acrylonitrile, glyc Copolymers of cydyl methacrylate, alkyl (meth) acrylate and dicyclopentanyl (meth) acrylate.

The weight average molecular weight of an acrylic resin may be 400,000-1,800,000, 500,000-1,500,000, or 800,000-1,400,000. When this weight average molecular weight is less than 400,000, since the viscosity of a liquid ink is low, the dispersion stability of an inorganic filler may fall, or a liquid ink may become unable to express thixotropy. Moreover, when the weight average molecular weight of an acrylic resin is low, a cured film will fall easily and it exists in the tendency for the bendability of a cured film to fall. When the weight average molecular weight of an acrylic resin exceeds 1.8 million, the solubility to a solvent will fall remarkably and it will become difficult to raise the density | concentration of solid content in a liquid ink. When the concentration of the solid content of the liquid ink is low, the necessity of considering the film thickness by controlling the film thickness of the applied liquid ink and drying shrinkage is high.

The glass transition temperature (Tg) of the acrylic resin may be -50 to 100 ° C, -45 to 20 ° C, or -40 ° C to 5 ° C. When the glass transition temperature of an acrylic resin exists in these numerical ranges, the storage elastic modulus and tensile elasticity modulus of a cured film can be easily controlled, suppressing sticking of a cured film. Although Tg of an acrylic resin can be measured by DSC (Differential scanning calorimetry), Tg of the acrylic resin comprised from n types of monomers can also be calculated by the following 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, W _i represents the mass fraction of each monomer, and W ₁ + W ₂ +. + W _i +… W _n = 1

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

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

The thermosetting resin which comprises a thermosetting resin composition is a compound which has a curable functional group (for example, epoxy group). The thermosetting resin is, for example, one selected from an epoxy resin, a polyimide resin, a polyamideimide resin, a triazine resin, a phenol resin, a melamine resin, a polyester resin, a cyanate ester resin and a modified system of these resins, or 2 or more types.

The thermosetting resin may 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 thermosetting resin is 3000 or less normally.

The epoxy resin is, for example, a polyglycol obtained by reacting epichlorohydrin with a polyhydric phenol such as bisphenol A, a novolac phenol resin, and an ortho cresol novolac phenol resin, or a polyhydric phenol such as 1,4-butanediol. N-glycidyl derivatives of a compound having a polyglycidyl ester, an amino group, an amide group or a heterocyclic nitrogen base obtained by reacting a polybasic acid such as cylyl ether, phthalic acid and hexahydrophthalic acid with epichlorohydrin, and an alicyclic ring It is 1 type, or 2 or more types chosen from a formula epoxy resin. Among them, N-glycidyl derivatives of a polyglycidyl ether selected from a biphenyl aralkyl type epoxy resin and a naphthalene type tetrafunctional epoxy resin, and a compound having an amide group or a heterocyclic nitrogen base include an organic polymer (especially , Acrylic resin).

As a phenol resin, the phenol resin of a phenol type, bisphenol A type, a cresol novolak type, and an amino triazine novolak type is mentioned, for example. From the compatibility with an acrylic resin, one or both of cresol novolak-type and aminotriazine novolak-type phenol resins can be selected. Amine triazine novolak-type phenol resin has a structural unit represented by following structural formula (I). When combined with an epoxy resin, a phenol resin may function as a hardening | curing agent of an epoxy resin.

[In formula (I), R represents a hydrogen atom or a methyl group, n represents the integer of 1-30.]

The thermosetting resin composition may contain the hardening | curing agent normally used in order to harden a thermosetting resin. For example, when a thermosetting resin is an epoxy resin, hardening | curing agents, such as a dicyandiamide, diaminodiphenylmethane, diaminodiphenyl sulfone, a phthalic anhydride, a pyromellitic anhydride, and a phenol novolak, cresol novolak, etc. It can be selected from polyfunctional phenols.

Often, an accelerator can be used for the purpose of promoting the reaction between the thermosetting resin and the curing agent. The kind and compounding quantity of an accelerator are not specifically limited. For example, an imidazole compound, an organophosphorus compound, a tertiary amine, and a quaternary ammonium salt are used and you may use two or more types together.

Based on the total mass of an 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 mass of components other than the inorganic filler of the thermosetting resin composition). 40-90 mass%, 50-85 mass%, or 60-80 mass% may be sufficient as the content rate of an organic polymer. The total of the glycidyl group of the acrylic resin and the epoxy group of the epoxy resin and the amount of hydroxyl groups of the phenol resin may be substantially equivalent. The ratio of a thermosetting resin and a hardening | curing agent is suitably set in the range currently employ | adopted in consideration of these reactivity etc ..

As a solvent which comprises a liquid ink, ketone solvents, such as methyl ethyl ketone and cyclohexanone, can be used, for example. Cyclohexanone can be selected from a viewpoint of printability. The concentration of the thermosetting resin composition (components other than the solvent) in the liquid ink may be 40 to 70% by mass based on the mass of the liquid ink.

Liquid ink can be prepared by mixing each component and the solvent which comprise a thermosetting resin composition, and stirring as needed. You may disperse | distribute an inorganic filler in the organic solvent containing a surface treating agent previously, and may make it slurry. Although solid content concentration (inorganic filler concentration) of the slurry containing an inorganic filler and a solvent is not specifically limited, 50-90 mass%, 60-80 mass%, or 65-75 mass% based on the mass of a slurry. It may be. You may prepare in advance the mixture of an organic polymer, a thermosetting resin, and a hardening | curing agent. This mixture and the slurry of an inorganic filler can be mixed and liquid ink can be obtained.

In order to form a cured film, the liquid ink which concerns on this embodiment is apply | coated to the predetermined part of a base material. The coating method may be, for example, continuous coating such as a bar coat, a comma coat, a roll coat, or a printing method such as screen printing or metal mask printing.

The apply | coated liquid ink (coating film) is hardened after drying as needed. 50-150 degreeC, 80-130 degreeC, or 100-120 degreeC may be sufficient as a drying temperature. The coating film is cured by further treating at high temperature. The curing temperature may be 150 to 250 ° C, 160 to 200 ° C, or 180 ° C to 190 ° C.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples.

Example 1

7 g of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, Shin-Etsu Silicone Co., Ltd. brand name) as a surface treating agent is melt | dissolved in 300 g of methyl ethyl ketone, and crushed silica F05-12 (Fukushima Yogyo Co., Ltd.) is put there. 700g of Kaisha brand name) was added stirring, Then, it stirred at room temperature for 1 hour further. The flocculated powder of crushed silica was filtered out using a 200 mesh nylon cloth to obtain a slurry-like filtrate (silica slurry). Methyl ethyl ketone (MEK) solution (concentration 20% by mass) of a copolymer of glycidyl methacrylate, ethyl acrylate and butyl acrylate, which is an acrylic resin (weight average molecular weight 1.3 million, epoxy equivalent 7800, Tg-45 ° C) 350 g of MEK solution (concentration 50 mass%) of biphenyl aralkyl type epoxy resin (NC-3000H, Nippon Kayaku Co., Ltd. brand name), phenol resin (LA-3018, Dainippon ink Co., Ltd. product) 25.8 g of a MEK solution (concentration of 50% by mass) of the MEK solution and 0.5 g of 1-cyanoethyl-2-phenylimidazole (2PZ-CN, manufactured by Shikoku Chemical Co., Ltd.) were mixed, stirred, and the resin. A solution was obtained. 430 g of silica slurry was added to this resin solution, and it stirred for 1 hour, and obtained liquid ink.

Examples 2-11, Reference Examples 1-4 and Comparative Examples 5-8

Liquid ink was prepared like Example 1 except having used each material shown in Table 1, 2 by the compounding ratio shown in the table. The compounding ratio of an organic polymer, a thermosetting resin, and a hardening | curing agent is based on the mass other than the inorganic filler of a thermosetting resin composition, and the compounding ratio of an inorganic filler is based on the mass of the total solid (components other than a solvent in a liquid ink) of a thermosetting resin composition. I did it.

Example 12

7 g of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, Shin-Etsu Silicone Co., Ltd. brand name) as a surface treating agent is melt | dissolved in 300 g of cyclohexanone, and SO-25R which is spherical silica (admatex addition) 700 g of the trade name (manufactured by Shikai Co., Ltd.) was added while stirring, and then further stirred at room temperature for 1 hour. Agglomerated powder of spherical silica was filtered out using a 200 mesh nylon cloth to obtain a slurry-like filtrate (silica slurry). 350 g of cyclohexanone solution (concentration 20% by mass) of a copolymer of glycidyl methacrylate, acrylonitrile, ethyl acrylate and butyl acrylate (weight average molecular weight 450,000, Tg-14. And 34.2 g of cyclohexanone solution (concentration 50 mass%) of biphenyl aralkyl type epoxy resin (NC-3000H, Nippon Kayaku Co., Ltd. brand name), and phenol resin (LA-3018, Dainippon ink) 25.8 g of propylene glycol monomethyl ether solution (concentration 50% by mass) manufactured by Kaisha Co., Ltd., and 0.5 g of 1-cyanoethyl-2-phenyl imidazole (2PZ-CN, manufactured by Shikoku Chemical Co., Ltd.) were mixed. It stirred and obtained the resin solution. 430 g of said silica slurry (70 mass% of inorganic fillers) was added to this resin solution, and it stirred for 1 hour, and obtained the liquid ink.

The detail of each material shown in Table 1, 2 is as follows.

1. 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 (monomer compounding ratio: GMA / EA / BA / FA513AS = 5/28 / 38.5 / 28.5 (mass ratio), Tg: -6.7 deg.

2. epoxy resin

NC-3000H: Biphenyl aralkyl type epoxy resin (Nippon Kayaku Co., Ltd. brand name, epoxy equivalent 290)

EXA4710: Naphthalene type tetrafunctional epoxy resin (the Dainippon Ink Co., Ltd. brand name, epoxy equivalent 170)

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

3. Phenolic resin (curing agent)

LA-3018: aminotriazine novolak type phenolic resin (trade name, product of hydroxyl group equivalent 151, nitrogen content 18% made by Dainippon Ink & Chemicals Co., Ltd.)

KA-1165: cresol novolac-type phenolic resin (trade name, manufactured by Dainippon Ink Co., Ltd., hydroxyl group equivalent 119)

LA-1356: aminotriazine novolac-type phenolic resin (trade name, product of hydroxy group equivalent 146, nitrogen content 19%) made by Dainippon Ink Co., Ltd.)

4. Silica Particles

F05-12: crushed silica, manufactured by Fukushima Yogyo Co., Ltd.

F05-30: crushed silica, manufactured by Fukushima Yogyo Co., Ltd.

SO-C6 / SO-E3: spherical silica, manufactured by Admatex Co., Ltd.

SO-25R: spherical silica, manufactured by Admatex Co., Ltd.

5. Surface treatment agent (silane coupling agent)

KBM573: N-phenyl-3-aminopropyltrimethoxysilane, the Shin-Etsu Silicone Co., Ltd. make

KBM602: N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.

KBM903: 3-aminopropyltrimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.

KBM5103: 3-acryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.

DMDS / TEMOS: polysiloxane oligomer formed from dimethyldimethoxysilane (DMDS) and tetramethoxysilane (TEMOS)

(evaluation)

1. Adhesiveness with polyimide film

The liquid ink was apply | coated to the polyimide film (Eupirex 50S) using the bar coater so that the thickness after drying might be 125 micrometers. 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 in close contact with the polyimide film. By the cutter knife, the cured film was divided | segmented into the board | substrate eye shape by ten sheaths of 2 mm space | interval, and 10 sheaths of 2 mm space | interval crossing these at right angles. After sticking the adhesive tape there, it was peeled off and the adhesiveness was evaluated based on the number of checkerboard eyes which remained on the polyimide film. When the number of checkerboard eyes left on the polyimide film was large, it was determined that the adhesiveness with the polyimide was good.

2. Storage modulus of cured product

To a release process PET (polyethylene terephthalate) film, the liquid ink of the quantity which becomes 125 micrometers in thickness after drying was apply | coated using the 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). From the hardened | cured material peeled from the release process PET film, the sample of width 5mm and length 30mm was punched. This sample was subjected to viscoelasticity measurement using a dynamic viscoelasticity measuring device (REOGEL4000 manufactured by Rheology Corporation) at a distance of 20 mm between chucks, a period of 10 Hz, and a temperature increase rate of 5 ° C / min. The storage elastic modulus and Tg in 25 degreeC were calculated | required from the obtained viscoelastic curve.

3. Mechanical Properties of Cured Product

To a release process PET (polyethylene terephthalate) film, the liquid ink of the quantity which becomes 125 micrometers in thickness after drying was apply | coated using the 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 sample of width 10mm and length 100mm was punched out from the hardened | cured material peeled from the release process PET film. This sample was subjected to a tensile test at a tensile speed of 50 mm / min using an EZ tester to obtain a stress-displacement curve. From the maximum value of the slope of the tangent line of the stress-displacement curve at the beginning, the tensile modulus was calculated according to the following equation. The stress-displacement curve of the cured product of the liquid ink obtained in Example 11 is shown in FIG. 2. The tensile modulus was calculated from the slope of the tangent T having the maximum slope among the tangent lines of the stress-displacement curve of FIG. 2.

Tensile modulus (Pa) = maximum value of slope of tangent of stress-displacement curve (N / m) ×

[Displacement (m) / cross section of hardened material (m ² )]

4. Self-support

The liquid ink of the quantity which becomes 125 micrometers in thickness after drying was apply | coated to the polyimide film (Eupirex 50S) using the 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 with the polyimide film to the size of width 10mm and length 100mm, and the sample was obtained. The obtained sample was placed on two pedestals provided at intervals of 80 mm so as to cover the pedestals, and the amount of sinking of the central portion of the sample at that time was measured. When the fall amount was 10 mm or less, it was determined that self-support was found.

5. Flexibility

A sample composed of a polyimide film and a cured film laminated thereon was brought into contact with a 0.3 mm pin gauge, bent to around 180 degrees while the sample was wound thereon, and the presence or absence of cracks at that time was observed. The polyimide film was arrange | positioned outside or inside with respect to the pin gauge, and the same evaluation was performed. When the occurrence of cracks was not confirmed, it was determined that bendability was good.

6. Downflowability

The sample comprised of the polyimide film and the cured film laminated | stacked on this was sandwiched between two wire meshes, and the conveyor type reflow test was done. That is, the sample was processed three times by the heating profile in which the maximum temperature of the sample surface is 260 degreeC at the speed | rate of 1.2 m / min, and the temperature is hold | maintained for 10 second. After the treatment, visual observation of the appearance confirmed the presence or absence of expansion and peeling between the polyimide film / cured film. When swelling and peeling were not confirmed, it was determined that the reflow property was good.

(result)

The liquid ink of the Example had the outstanding dispersion stability, and the aggregation of the silica was not seen even after standing for two weeks. Self-supporting property was able to be provided to the polyimide film by the cured film formed by these liquid inks. Moreover, the adhesiveness with respect to the polyimide of a cured film was also favorable, and there was no problem of reflow property. Since the liquid ink of Reference Example 1 aggregated with silica, there was a problem in stability. The liquid inks of Reference Examples 2 and 3 had a problem in stability because the resin was separated. The cured film formed of the liquid ink of Comparative Example 5 could not impart self-supportability to the polyimide film. 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 storage modulus at 25 ° C. of the cured product formed by the liquid ink of Reference Example 4 having a composition excluding silica particles from the liquid ink of Example 3 was a value substantially the same as that of the cured product of Example 3. From this, it was confirmed that the storage elastic modulus at 25 degrees C of hardened | cured material is a value in which the elasticity modulus of the resin component except an inorganic filler was mainly reflected.

One … Cured Film (Hardened)
10... materials

Claims (12)

It contains the thermosetting resin composition containing an organic polymer, a thermosetting resin, and an inorganic filler, and the solvent which melt | dissolves or disperse | distributes the said thermosetting resin composition,
The organic polymer comprises an acrylic resin,
The thermosetting resin comprises an epoxy resin,
The inorganic filler comprises silica particles,
The thermosetting resin composition contains 50% by mass or more and 90% by mass or less of the inorganic filler based on the mass of the thermosetting resin composition,
When the thermosetting resin composition is cured, the liquid ink having a storage modulus at 25 ° C of 10 MPa or more and 120 MPa or less and a cured product having a tensile modulus of 0.5 GPa to 3.0 GPa. The method of claim 1,
Liquid ink whose weight average molecular weights of the said acrylic resin are 400,000-1.8 million. The method according to claim 1 or 2,
Liquid ink in which the said silica particle is surface-treated by the silane coupling agent. The method of claim 3,
The liquid ink, wherein the silane coupling agent has an amino group. The method according to claim 1 or 2,
The liquid ink, wherein the thermosetting resin composition further comprises a phenol resin. The method of claim 5,
The liquid ink, wherein the epoxy resin comprises a biphenyl aralkyl type epoxy resin. The method according to claim 1 or 2,
A liquid ink, which is used to apply a liquid ink to a polyimide film substrate, and to cure the applied liquid ink to form a cured film that increases the rigidity of the polyimide film substrate. The method according to claim 1 or 2,
Liquid ink which is used to apply a liquid ink to a flexible printed wiring board and harden the applied liquid ink to form a cured film which raises the rigidity of the flexible printed wiring board. delete delete delete delete

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