JP5332102B2 - Liquid composition, resistor, resistor element and wiring board - Google Patents

Description

  The present invention relates to a liquid composition, a resistor, a resistor element, and a wiring board.

  Conventionally, a multilayer printed wiring board is formed by pressing and laminating a single-sided printed wiring board or a double-sided printed wiring board in which a circuit is formed by etching through an adhesive layer such as a glass woven prepreg, and drilling, laser, Etc., and further, electrically conductive layers of different layers are electrically connected by plating or the like.

  In recent years, for example, Patent Document 1 proposes a method for forming a wiring pattern by an inkjet printing method as a method for manufacturing a multilayer printed wiring board that replaces such a conventional manufacturing method. Patent Document 2 proposes a method for manufacturing a printed wiring board by an offset printing method. Patent Document 3 proposes a method of manufacturing a multilayer printed wiring board by forming a conductor layer and an insulating layer having a hole on a substrate by a printing method.

  According to these manufacturing methods, it is possible to manufacture a multilayer printed wiring board without using large-scale equipment such as press equipment and plating equipment. In addition, since the conductor ink or the insulator ink can be printed only in a necessary place, there is an advantage that the material use efficiency is very high.

  By the way, in recent years, with the demand for miniaturization and weight reduction of electronic devices, there has been an increasing demand for thinner and higher density wiring boards. In particular, for electronic devices in the information communication field and information processing field, with the demand for higher functionality, there is an increasing need to ensure a sufficient mounting area for mounting components. Up to now, in order to secure a sufficient mounting area, miniaturization of surface mounting components, narrowing of terminal pitch, fine patterning of base material, SMT (surface mounting technology) for mounting components on the surface of base material with high density The advanced SMT, etc. that have been advanced, have been studied.

  However, as the number of active elements (chip parts) increases with the demand for higher functionality, the number of passive elements (capacitors, inductors, resistors) that perform electrical adjustments also increases. . As a result, the mounting area of the passive elements may occupy more than half of the whole, which has been an obstacle to miniaturization and higher functionality of electronic devices.

  Therefore, development of a technique for integrating the passive element with the base material is in progress. Such technology eliminates solder joints used for electrical connection between surface mount components and wiring boards, improving connection reliability, increasing circuit design freedom, and passive elements. Can be formed at a desired position and the wiring length can be shortened, thereby reducing parasitic capacitance, improving electrical characteristics, eliminating the need for surface mounting, and reducing costs. Is expected.

Conventionally, as such a technique, for example, Patent Documents 4 and 5 propose a technique of forming a resistor on a substrate by plating a metal having a relatively high resistance. On the other hand, Non-Patent Document 1 proposes a technique for forming a resistor on a substrate using an ink jet printing method without passing through steps such as plating and etching.
JP 2003-80694 A JP-A-11-58921 JP 2003-110242 A Japanese Patent No. 11191906 US Pat. No. 3,808,576 Nikkei Electronics 6/17, p. 67-78 (2002), “Blowing the limits of miniaturization of equipment with inkjet”

  Among the above-described techniques, a technique for forming a resistor on a substrate using an inkjet printing method as described in Non-Patent Document 1 is a process of plating, etching, and the like on a resistor integrated with the substrate. It is excellent in that it can be easily formed and the environmental load during the production of the resistor can be reduced.

  In the ink jet printing method, ink is ejected by the ink jet head. Therefore, in order to prevent clogging of the ink jet head and stably realize good printing on the substrate surface, the resistor forming ink has a viscosity. And a small dispersed particle size of the contained particles are preferable. However, conventional resistor-forming inks (for example, polymer resistor pastes for screen printing) have high viscosity and a large dispersed particle size. There was a problem that printing could not be realized stably.

  Therefore, the present invention stably realizes good printing on the substrate surface even when the ink jet printing method is used because the viscosity is sufficiently low and the dispersed particle diameter of the contained particles is sufficiently small. An object of the present invention is to provide a resistor-forming ink that can be used.

In order to achieve the above object, the present invention provides:
An epoxy resin, carbon black particles, a solvent having a vapor pressure of less than 1.34 × 10 ³ Pa at 25 ° C., a curing agent, and a curing accelerator,
Provided is a liquid composition in which at least a part of the curing agent or the curing accelerator is an imidazole compound.

  Since the liquid composition of the present invention has a sufficiently low viscosity and the dispersed particle diameter of contained particles (carbon black particles) is sufficiently small, even when a resistor is formed using an inkjet printing method, It can be used as an ink for forming a resistor capable of stably realizing good printing on the substrate surface. And by using the liquid composition of the present invention as the resistor forming ink, it becomes possible to stably realize good printing on the substrate surface even when using the ink jet printing method. The integrated resistor can be formed simply, stably, and without applying a large load to the environment. In addition, it is possible to efficiently form a resistor having a resistivity suitable for the resistor and having a fine pattern on the substrate.

  In order to suppress an increase in the viscosity of the liquid composition, the imidazole compound is preferably a compound in which a substituent (a group other than a hydrogen atom) is bonded to the 1-position nitrogen atom of the imidazole ring. From the same viewpoint, a compound in which a substituent having 3 or more carbon atoms is bonded to the carbon atom at the 2-position of the imidazole ring is preferable.

  Examples of the substituent bonded to the nitrogen atom at the 1-position of the imidazole ring include a cyanoethyl group, a methyl group, and a benzyl group. The substituent having 3 or more carbon atoms bonded to the carbon atom at the 2-position of the imidazole ring is preferably a substituent having 6 or more carbon atoms. Examples of the substituent having 6 or more carbon atoms include a phenyl group and an undecyl group. And a heptadecyl group.

  The average dispersed particle size of the carbon black particles is preferably 500 nm or less, and the maximum dispersed particle size is preferably 2 μm or less. If the average dispersed particle diameter exceeds 500 nm, or the maximum dispersed particle diameter exceeds 2 μm, the stability of printing and resistance development tends to decrease. For example, when the ink jet printing method is used, clogging of ink jet head nozzles or the like occurs, and it tends to be difficult to perform stable printing. Further, when the offset printing method is used, the printed matter tends to be blurred. In the present specification, the “dispersed particle size” means a particle size measured by a photon correlation method based on a dynamic light scattering method based on Brownian motion of particles.

  Moreover, it is preferable that content of the said carbon black particle is 10-80 volume% with respect to the total volume of all the components of liquid compositions other than a solvent. If the content of the carbon black particles is less than 10% by volume, it tends to be difficult to set the volume resistivity of the resistor to a desired value. On the other hand, when it is larger than 80% by volume, the viscosity of the liquid composition increases, and the printing stability tends to decrease, and the strength of the resistor tends to decrease.

  In order to suppress a decrease in printing stability, the liquid composition of the present invention preferably has a viscosity at 25 ° C. of 50 mPa · s or less.

  In order to suppress a decrease in the heat resistance and connection reliability of the resistor, the epoxy resin is preferably a glycidyl etherified product of a condensate of a phenol compound and an aldehyde compound, and the curing agent is a phenol compound and A condensate with an aldehyde compound is preferred.

  After the liquid composition of the present invention is attached to the substrate by a printing method, a coating method, etc., when the liquid composition is heated, the epoxy resin in the liquid composition is cured, and the solvent is removed. A resistor is formed. That is, this invention also provides the resistor obtained by making the liquid composition of this invention adhere on a base material, and heating the said liquid composition. The resistor of the present invention has a volume resistivity suitable as a resistor.

  The present invention further provides a resistor element including the resistor and a wiring board on which the resistor element is formed. These resistor elements and wiring boards are useful for reducing the size and increasing the functionality of electronic devices.

  According to the present invention, the viscosity is sufficiently low and the dispersed particle diameter of the contained particles is sufficiently small, and even when the ink jet printing method is used, good printing on the substrate surface can be stably realized. A resistor forming ink that can be used, and a resistor, a resistor element, and a wiring board that can be obtained using the ink are provided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the drawings, the same or equivalent elements are denoted by the same reference numerals.

(Liquid composition)
The liquid composition of the present invention contains an epoxy resin, carbon black particles, a solvent having a vapor pressure of less than 1.34 × 10 ³ Pa at 25 ° C., a curing agent, and a curing accelerator. .

  The carbon black particles are contained as a conductive material. In order to suppress a decrease in the stability of printing and resistance development, the primary particle size of the carbon black particles is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 50 nm or less. From the same viewpoint, the average dispersed particle size of the carbon black particles is preferably 500 nm or less, more preferably 300 nm or less. From the same viewpoint, the maximum dispersed particle size is preferably 2 μm or less, more preferably 1 μm or less. Here, the dispersed particle size (average dispersed particle size, maximum dispersed particle size) is measured by a photon correlation method based on a dynamic light scattering method using Brownian motion of particles.

  The content of the carbon black particles is preferably 10 to 80% by volume with respect to the total volume of all components of the liquid composition other than the solvent. If the content of the carbon black particles is less than 10% by volume, it tends to be difficult to set the volume resistivity of the resistor to a desired value. On the other hand, when it is larger than 80% by volume, the viscosity of the liquid composition increases, and the printing stability tends to decrease, and the strength of the resistor tends to decrease. In terms of printing stability and resistance strength, the content of carbon black particles is more preferably 10 to 70% by volume with respect to the total volume of all components of the liquid composition other than the solvent.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenol type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, and glycidyl ester type epoxy resin. And glycidyl etherified products and bifunctional phenolic compounds of condensates of phenolic compounds such as phenol, cresol, alkylphenol, catechol, bisphenol F, bisphenol A, bisphenol S and aldehyde compounds such as formaldehyde and salicylaldehyde. Examples thereof include glycidyl etherified products, glycidyl etherified products of bifunctional alcohols, glycidyl etherified products of polyphenol compounds, and hydrogenated products and halides thereof. In order to suppress a decrease in the heat resistance and connection reliability of the resistor, the epoxy resin is preferably a glycidyl etherified product of a condensate of a phenol compound and an aldehyde compound. There is no restriction | limiting in particular in the molecular weight of an epoxy resin, You may use 2 or more types of epoxy resins together.

  Examples of the curing agent include amines such as diethylenetriamine, triethylenetetramine, metaxylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, m-phenylenediamine, and dicyandiamide; phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl Acid anhydrides such as tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl nadic anhydride, pyromellitic anhydride, trimellitic anhydride; phenolic compounds such as bisphenol F, bisphenol A, bisphenol S, polyvinylphenol; phenol, Phenol compounds such as cresol, alkylphenol, catechol, bisphenol F, bisphenol A, bisphenol S, formaldehyde, salicylaldehyde Like and like these halides; and aldehyde compounds such as condensates of. In order to suppress a decrease in the heat resistance and connection reliability of the resistor, a condensate of a phenol compound and an aldehyde compound is preferable as the curing agent. There is no particular limitation on the molecular weight of the curing agent, and two or more curing agents may be used in combination.

  Although content of a hardening | curing agent may be in the range employ | adopted conventionally, the quantity from which a hydroxyl group equivalent will be 0.5-2.0 equivalent with respect to an epoxy equivalent is preferable. In the case of dicyandiamide, the amount is preferably 2 to 5 parts by mass with respect to 100 parts by mass of the epoxy resin.

  Examples of the curing accelerator include imidazole compounds (for example, imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2 -Heptadecylimidazole, 4,5-diphenylimidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl- 4-methylimidazole, 2-ethylimidazoline, 2-isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline, 1-cyanoethyl-2-methylimidazole, 1-cyanoe Ru-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2- Feirimidazolium trimellitate, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and imino group is acrylonitrile, phenylene diisocyanate, toluidine isocyanate, naphthalene diisocyanate, methylene Imidazoles masked with bisphenyl isocyanate or melamine acrylate), organophosphorus compounds, tertiary amines, and quaternary ammonium salts.

  Although content of a hardening accelerator may be in the range employ | adopted conventionally, it is preferable that it is 0.001-15 mass parts with respect to 100 mass parts of epoxy resins. When the content of the curing accelerator is less than 0.001 part by mass, the curability of the liquid composition tends to be insufficient. On the other hand, when the content exceeds 15 parts by mass, the pot life of the liquid composition decreases. Tend. In terms of curability and pot life of the liquid composition, the content of the curing accelerator is more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin.

  In the liquid composition of the present invention, at least a part of the curing agent or curing accelerator is an imidazole compound. In order to suppress an increase in the viscosity of the liquid composition, the imidazole compound is preferably a compound in which a substituent (a group other than a hydrogen atom) is bonded to the nitrogen atom at the 1-position of the imidazole ring. From the same viewpoint, a compound in which a substituent having 3 or more carbon atoms is bonded to the carbon atom at the 2-position of the imidazole ring is preferable.

  Examples of the substituent bonded to the nitrogen atom at the 1-position of the imidazole ring include a cyanoethyl group, a methyl group, and a benzyl group. The substituent having 3 or more carbon atoms bonded to the carbon atom at the 2-position of the imidazole ring is preferably a substituent having 6 or more carbon atoms. Examples of the substituent having 6 or more carbon atoms include a phenyl group and an undecyl group. And a heptadecyl group.

  Examples of the compound in which a substituent is bonded to the nitrogen atom at the 1-position of the imidazole ring or a substituent having 3 or more carbon atoms is bonded to the carbon atom at the 2-position of the imidazole ring include, for example, 2-undecyl Imidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenyl Imidazolium trimellitate, 2,4-diamy -6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-methylimidazolyl- (1' )] Ethyl-s-triazine isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and imino group is acrylonitrile, phenylene diisocyanate, toluidine Mass by isocyanate, naphthalene diisocyanate, methylene bisphenyl isocyanate, melamine acrylate, etc. Imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 4,5-diphenyl Imidazole, 2-methylimidazoline, 2-phenylimidazoline, 2-undecylimidazoline, 2-heptadecylimidazoline, 2-isopropylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole, 2-ethylimidazoline, 2-Isopropylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4-methylimidazoline, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-silane Anoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-feylimidazolium trimellitate, 2-phenyl-4, 5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole are mentioned.

The liquid composition contains a solvent having a vapor pressure at 25 ° C. of 1.34 × 10 ³ Pa or less. Such a solvent is not particularly limited as long as it can dissolve or disperse other components such as an epoxy resin. For example, γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamide And cyclohexanone. The vapor pressure of the solvent is preferably 0.005 × 10 ^{3 to} 1.34 × 10 ³ Pa.

The liquid composition may contain a solvent having a vapor pressure higher than 1.34 × 10 ³ Pa at 25 ° C. in addition to the solvent. Such a solvent is not particularly limited as long as it can dissolve or disperse other components such as an epoxy resin, and examples thereof include methyl isobutyl ketone, methyl ethyl ketone, and toluene. In order to suppress the decrease in the viscosity of the liquid composition during printing or coating and the flow of the liquid composition after printing or coating, the mixing ratio of such a solvent is preferably 60% with respect to the whole solvent. Below, more preferably 50% or less, and still more preferably 40% or less.

  In order to suppress a decrease in printing stability, the viscosity of the liquid composition at 25 ° C. is preferably 100 mPa · s or less, particularly preferably 50 mPa · s or less. The viscosity of the liquid composition at 25 ° C. is preferably 1 mPa · s or more.

  In order to reduce the dispersed particle size (average dispersed particle size, maximum dispersed particle size) of the carbon black particles, the carbon black particles in the solvent in a liquid composition state or in a mixture state of the carbon black particles and the solvent. Is preferably dispersed with a disperser or the like. As a disperser, a raking machine, a three-roll mill, a bead mill, a sand mill, or the like can be used alone or in combination of two or more. Further, the carbon black particles can be dispersed by an apparatus equipped with an ultrasonic oscillator. When bubbles are generated in the liquid composition after dispersion, the bubbles are preferably removed by leaving or stirring under reduced pressure.

  In order to improve the dispersibility of the carbon black particles, the liquid composition preferably contains a dispersant suitable for the carbon black particles. Thereby, it becomes easy to reduce the dispersed particle size (average dispersed particle size, maximum dispersed particle size) of the particles, and the dispersion stability of the particles can be improved. Moreover, in order to make the maximum dispersed particle diameter 2 μm or less, it is preferable to filter the liquid composition with a filter having an opening diameter 2 μm or less. Thereby, the yield at the time of preparation of a liquid composition can be improved.

  The liquid composition may appropriately contain a coupling agent, an ion scavenger, a viscosity modifier, inorganic insulating particles, and the like in addition to the above-described components.

(Resistors, resistor elements and wiring boards)
After the liquid composition of the present invention is attached to the substrate by a printing method, a coating method, etc., when the liquid composition is heated, the epoxy resin in the liquid composition is cured, and the solvent is removed. A resistor is formed. That is, this invention also provides the resistor obtained by making the liquid composition of this invention adhere on a base material, and heating the said liquid composition. The present invention further provides a resistor element including the resistor, and a wiring board on which the resistor element is formed.

  FIG. 1 is a perspective view showing a wiring board according to a preferred embodiment of the present invention, and FIG. 2 is an end view taken along line II-II in FIG. A wiring board 1 shown in FIGS. 1 and 2 includes a plate-like base material 3 and a resistor element 5 provided on one surface of the base material 3. The resistor element 5 includes a conductor 12 forming a pair of electrodes and a resistor 11 formed so as to electrically connect the pair of conductors 12. The thickness of the resistor 11 is not particularly limited, but is typically 200 to 500,000 nm.

  The resistor 11 can be formed by, for example, attaching the liquid composition of the present invention on the substrate 3 so as to be in contact with the conductor 12, and then heating the liquid composition. When the liquid composition is heated, the epoxy resin in the liquid composition is cured and the solvent is removed. That is, the resistor 11 contains a cured product of epoxy resin and carbon black particles. The heating conditions (temperature, time, etc.) when forming the resistor 11 can be appropriately determined according to the type of solvent, etc., so that the epoxy resin is sufficiently cured and the solvent is sufficiently removed. .

  As a method for attaching the liquid composition, any method capable of forming a resistor having a desired thickness may be used, and a known printing method or coating method may be used. The ink jet printing method or the offset printing method is preferable because it is easy to form the resistor at any position and in any shape. Ink-jet printing is particularly preferred because it can be carried out easily without requiring a plate during printing.

  The conductor 12 is made of a conductive material such as copper. Although the method in particular of forming the conductor 12 is not restrict | limited, For example, an etching, plating, printing, etc. are mentioned.

  Examples of the base material 3 include paper phenol insulation plates, glass / bismaleimide insulation plates, glass / polyimide insulation plates and other insulating substrates; polyimides used for flexible wiring boards, etc .; plastic films such as polyethylene naphthalate; glass plates, etc. Is preferred.

  Hereinafter, based on an Example and a comparative example, this invention is demonstrated more concretely. However, the present invention is not limited to the following examples.

  In the following Examples and Comparative Examples, the viscosity of the liquid composition was measured at 25 ° C. using a small vibration viscometer CJV5000 manufactured by A & D Co., Ltd. Further, the average dispersed particle size and the maximum dispersed particle size in the liquid composition were measured at 25 ° C. using a submicron particle analyzer N5 type manufactured by Beckman Coulter. Moreover, volume resistivity was measured using Mitsubishi Chemical Loresta GP.

Example 1
Carbon black slurry in which carbon black particles are dispersed in γ-butyrolactone (carbon black particle content: 20%, average dispersed particle size: 115 nm, maximum dispersed particle size: 300 nm) and 87 g of γ-butyrolactone are mixed. In addition, 5.2 g of “N-865”, 2.8 g of “VH-4170”, and 0.26 g of 1-cyanoethyl-2-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed, and the viscosity was 25 mPa · s, a liquid composition having an average dispersed particle size / maximum dispersed particle size of carbon black particles of 130 nm / 300 nm was obtained.

( Reference Example 2)
A liquid composition was obtained in the same manner as in Example 1 except that 2-phenylimidazole was used as the imidazole compound. The viscosity of the liquid composition was 28 mPa · s, and the average dispersed particle size / maximum dispersed particle size of the carbon black particles was 125 nm / 300 nm.

( Reference Example 3)
A liquid composition was obtained in the same manner as in Example 1 except that 2-undecylimidazole was used as the imidazole compound. The viscosity of the liquid composition was 29 mPa · s, and the average dispersed particle size / maximum dispersed particle size of the carbon black particles was 128 nm / 280 nm.

(Comparative Example 1)
A liquid composition was obtained in the same manner as in Example 1 except that 2-ethyl-4-methylimidazole was used as the imidazole compound. The viscosity of the liquid composition was 105 mPa · s, and the average dispersed particle size / maximum dispersed particle size of the carbon black particles was 130 nm / 300 nm.

(Comparative Example 2)
A liquid composition was obtained in the same manner as in Example 1 except that 2-methylimidazole was used as the imidazole compound. The viscosity of the liquid composition was 86 mPa · s, and the average dispersed particle size / maximum dispersed particle size of the carbon black particles was 140 nm / 320 nm.

(Printability evaluation)
When the liquid compositions obtained in Example 1 , Reference Examples 2 to 3 and Comparative Examples 1 and 2 were printed on the surface of the substrate (glass plate) with an inkjet printing apparatus, the liquid compositions obtained in Examples 1 to 3 The composition was able to print well without causing clogging of the inkjet head. On the other hand, the liquid compositions obtained in Comparative Examples 1 and 2 had a high viscosity and could not be printed with an inkjet printing apparatus.

(Volume resistivity measurement)
The liquid composition obtained in Example 1 and Reference Examples 2 to 3 was applied so that the thickness after curing was 10 μm, and then heated at 210 ° C. for 1 hour, whereby the epoxy resin in the liquid composition Was cured and the solvent was removed to obtain a resistor. The volume resistivity (Ω · cm) of this resistor was measured.

  The results of evaluation of printability and measurement of volume resistivity are shown in Table 1 below.

As is clear from Table 1, the liquid compositions obtained in Comparative Examples 1 and 2 could not be printed, whereas the liquid compositions obtained in Example 1 and Reference Examples 2 to 3 were Good printability was exhibited. Moreover, the resistor produced from the liquid composition obtained in Example 1 and Reference Examples 2 to 3 exhibited a volume resistivity suitable as a resistor.

  According to the above examples and comparative examples, the liquid composition of the present invention has a sufficiently low viscosity, and the dispersed particle diameter of the contained particles is sufficiently small. According to this liquid composition, the ink jet printing method is used. It was also shown that good printing on the substrate surface can be realized stably. Moreover, it was shown that the resistor obtained by heating the liquid composition after depositing the liquid composition of the present invention on the substrate has a volume resistivity suitable as a resistor.

  The liquid composition, resistor, resistor element and wiring board of the present invention can be used for downsizing and enhancement of functionality of electronic equipment.

1 is a perspective view showing a wiring board according to a preferred embodiment of the present invention. FIG. 2 is an end view taken along line II-II in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wiring board, 3 ... Base material, 5 ... Resistor element, 11 ... Resistor, 12 ... Conductor.

Claims (8)

An epoxy resin, carbon black particles, a solvent having a vapor pressure of less than 1.34 × 10 ³ Pa at 25 ° C., a curing agent, and a curing accelerator,
At least a part of the curing agent or curing accelerator is an imidazole compound,
The imidazole compound, Ri compound der which cyanoethyl groups in 1-position nitrogen atom of the imidazole ring, a methyl group or a benzyl group bonded,
A liquid composition for forming a resistor for an inkjet printing method , wherein the content of the carbon black particles is 10 to 80% by volume based on the total volume of all components of the liquid composition other than the solvent . Average dispersion particle size and maximum dispersion particle size measured by photon correlation method based on dynamic light scattering method by Brownian motion of particles, measured at 25 ° C. using Beckman Coulter Submicron Particle Analyzer Model N5 The liquid composition according to claim 1, wherein an average dispersed particle size and a maximum dispersed particle size of the carbon black particles are 500 nm or less and 2 μm or less, respectively. The liquid composition of Claim 1 or 2 whose viscosity measured at 25 degreeC using the small vibration type viscometer CJV5000 by A & D Co., Ltd. is 50 mPa * s or less. The liquid composition according to any one of claims 1 to 3 , wherein the epoxy resin is a glycidyl etherified product of a condensate of a phenol compound and an aldehyde compound. The liquid composition according to any one of claims 1 to 4 , wherein the curing agent is a condensate of a phenol compound and an aldehyde compound. The resistor obtained by making the liquid composition as described in any one of Claims 1-5 adhere on a base material, and heating the said liquid composition. A resistor element comprising the resistor according to claim 6 . A wiring board on which the resistor element according to claim 7 is formed on the substrate.

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