JP7203013B2 - Curable resin compositions, dry films, cured products and electronic components - Google Patents

Description

The present invention relates to a curable resin composition, dry film, cured product and electronic component.

Electronic components include wiring boards, and active and passive components fixed to the wiring boards. Some wiring boards connect and fix active and passive components by applying conductor wiring to an insulating base material. An insulating base material is sometimes used, and it is an important electronic component in electronic equipment. Wiring boards are also used in semiconductor packages, and curable resin compositions and dry films for wiring boards are used as wiring boards and outer layers after semiconductor packaging. Active components and passive components include transistors, diodes, resistors, coils, capacitors and the like.

In recent years, with the miniaturization of electronic devices, the required characteristics of electronic components have become stricter. There has been a demand for higher wiring density in wiring boards, and low thermal expansion is required for wiring board materials in order to ensure the reliability of wiring and component connections. Active components and passive components are also required to be miniaturized and highly integrated, and similarly low thermal expansion is required to ensure reliability.

As a method of achieving low thermal expansion, for example, Patent Document 1 proposes a method of filling resin with an inorganic filler to obtain a low coefficient of thermal expansion.

JP-A-2001-72834

However, with the material described in Patent Document 1, a large amount of inorganic filler must be filled in order to obtain a desired low coefficient of thermal expansion, and there is a problem that the physical properties of the cured product are inferior.
Furthermore, the inventors of the present invention have found that the material described in Patent Document 1 has a large coefficient of thermal expansion in a temperature range exceeding 200°C during component mounting, and is not effective for ensuring reliability. I noticed a new problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a curable resin composition capable of obtaining a cured product capable of maintaining a low coefficient of thermal expansion even in a high temperature range during component mounting.
Another object of the present invention is to provide a dry film, a cured product and an electronic component using the curable resin composition.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using fine powder with at least one dimension smaller than 100 nm and an active ester compound, and have completed the present invention.

That is, the curable resin composition of the present invention is characterized by comprising a fine powder having at least one dimension smaller than 100 nm (hereinafter also simply referred to as "fine powder") and an active ester compound. be. The curable resin composition of the present invention preferably further contains a filler.

The dry film of the present invention is characterized by having a resin layer obtained by applying the curable resin composition on a film and drying the composition.

The cured product of the present invention is obtained by curing the curable resin composition or the resin layer of the dry film.

An electronic component of the present invention is characterized by comprising the cured product.

Here, in the present invention, the fine powder is not particularly limited in shape, and may be fibrous, scaly, granular, or the like. It means smaller than 100 nm in any one, two or three dimensions. For example, in the case of fibrous fine powder, the two dimensions are smaller than 100 nm, and the remaining one dimension is spread, and in the case of scale-like fine powder, one side is smaller than 100 nm and remains. Examples thereof include those having a two-dimensional spread, and in the case of granular fine powders, examples thereof include those smaller than 100 nm in all three dimensions.
Further, in the present invention, the one-dimensional, two-dimensional and three-dimensional sizes of the fine powder are determined by examining the fine powder by SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope), or It can be observed and measured with an AFM (Atomic Force Microscope) or the like.
For example, in the case of scale-like fine powder, the average value of the thickness, which is the smallest one dimension, is measured and this average thickness is made smaller than 100 nm. Specifically, a line is drawn on the diagonal line of the micrograph, and 12 fine powders in the vicinity of the line and whose thickness can be measured are randomly extracted, and the thickest fine powder and the thinnest fine powder are selected. After removal, the thickness of the remaining 10 points is measured and the average value is less than 100 nm.
In the case of fibrous fine powder, the average value of the smallest two-dimensional fiber diameter is measured and this average fiber diameter is made smaller than 100 nm. Specifically, a line is drawn on the diagonal line of the micrograph, 12 points of fine powder in the vicinity are randomly extracted, and after removing the fine powder with the thickest and thinnest fiber diameters, the remaining 10 Measure the fiber diameter of the points and average the value to be less than 100 nm.
In the case of granular fine powders, the average particle size is measured and this average particle size is less than 100 nm. Specifically, a line is drawn on the diagonal line of the micrograph, 12 points of fine powder in the vicinity are randomly extracted, and after removing the fine powder with the largest and smallest particle sizes, the remaining 10 The particle size of the dots is measured and the average value is less than 100 nm.
For fine powders with extension in other dimensions such as fibrous or scaly, the extension is for example less than 1000 nm, preferably less than 650 nm, more preferably less than 450 nm. If the spread is less than 1000 nm, it is possible to effectively obtain the reinforcing effect due to the interaction between the fine powders.

ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which can obtain the hardened|cured material which can maintain a low coefficient of thermal expansion even in the high temperature area|region at the time of component mounting can be provided.
Moreover, according to the present invention, it is possible to provide a dry film, a cured product, and an electronic component using the curable resin composition.

1 is a partial cross-sectional view showing one configuration example of a multilayer printed wiring board according to one example of an electronic component of the present invention; FIG. It is an explanatory view showing a test board used in an example.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
The curable resin composition of the present invention is characterized by containing fine powder and an active ester compound.
With such a configuration, it is possible to maintain a low coefficient of thermal expansion even in a temperature range exceeding 200° C. during component mounting, and furthermore, by lowering the dielectric constant and dielectric loss tangent, low dielectric characteristics can be achieved. It is possible to obtain an electronic component having

[Fine powder]
The fine powder used in the present invention is a powder having at least one dimension smaller than 100 nm. and a sheet-like (scale-like) having a thickness of less than 100 nm. Such fine powders have a much larger surface area per unit mass than powders with all three dimensions of 100 nm or more, and the proportion of atoms exposed to the surface is increased. Therefore, it is considered that the fine powder interacts with each other to exert a reinforcing effect and reduce the thermal expansibility. This effect is remarkably exhibited even among fine powders having hydrophilic properties.

The fine powder is not particularly limited as long as it is a particle smaller than 100 nm in at least one dimension. Examples of fine powders include carbon-based materials such as fullerene, single-walled carbon nanotubes, and multi-walled carbon nanotubes, and inorganic materials such as silver, gold, iron, nickel, titanium oxide, cerium oxide, zinc oxide, silica, and aluminum hydroxide. Nanotubes, nanowires, nanosheets processed organic matter, minerals such as clay, smectite, bentonite, and only the crystal part is isolated from fine cellulose fibers and cellulose raw materials obtained by opening plant fibers. cellulose nanocrystal particles, fine chitin obtained by opening chitin obtained from crustaceans and the like, and fine chitosan subjected to alkali treatment. Among these, the hydrophilic fine powder includes metal oxide fine particles such as titanium oxide, metal hydroxide fine particles such as aluminum hydroxide, mineral fine particles such as clay, fine cellulose fibers, and fine chitin. . Among such fine powders, fine cellulose fibers are particularly desirable from the viewpoint of reinforcing effect and ease of handling. Cellulose nanocrystal particles are also preferred.

When hydrophilic fine powder is used as the fine powder described above, it is preferable to subject the particles to hydrophobic treatment or surface treatment using a coupling agent. For such treatment, known and commonly used methods suitable for fine powders can be used.

The amount of the fine powder to be blended in the present invention is preferably 0.04 to 64% by mass, more preferably 0.08 to 30% by mass, more preferably 0.08 to 30% by mass, based on the total amount of the composition excluding the solvent, It is 0.1 to 10% by mass. When the content of the fine powder is 0.04% by mass or more, the effect of reducing the coefficient of linear expansion can be satisfactorily obtained. On the other hand, when it is 64% by mass or less, the film formability is improved.

(fine cellulose fiber)
Among the fine powders according to the present invention, fine cellulose fibers can be obtained in the following manner, but are not limited to these.

As raw materials for fine cellulose fibers, use pulp obtained from natural plant fiber raw materials such as wood, hemp, bamboo, cotton, jute, kenaf, beets, agricultural waste, cloth, etc., and regenerated cellulose fibers such as rayon and cellophane. Among them, pulp is particularly suitable. The pulp includes chemical pulp such as kraft pulp and sulfite pulp obtained by chemically or mechanically pulping plant raw materials, or a combination of both, semi-chemical pulp, chemi-grand pulp, chemi-mechanical pulp, Thermomechanical pulp, chemithermomechanical pulp, refiner mechanical pulp, groundwood pulp, deinked waste paper pulp, magazine waste paper pulp, corrugated waste paper pulp, etc. containing these plant fibers as the main component can be used. Among them, various softwood-derived kraft pulps having high fiber strength, such as softwood unbleached kraft pulp, softwood oxygen-exposed unbleached kraft pulp, and softwood bleached kraft pulp, are particularly suitable.

The raw material is mainly composed of cellulose, hemicellulose and lignin, and the content of lignin is usually about 0 to 40% by mass, particularly about 0 to 10% by mass. As for these raw materials, if necessary, lignin can be removed or bleached to adjust the amount of lignin. In addition, the measurement of lignin content can be performed by the Klason method.

In the cell walls of plants, cellulose molecules are not single molecules but are regularly aggregated to form crystalline microfibrils (fine cellulose fibers), which are the basic skeletal substances of plants. ing. Therefore, in order to produce fine cellulose fibers from the above raw materials, the above raw materials are subjected to beating or crushing treatment, high-temperature and high-pressure steam treatment, treatment with phosphate, etc., and oxidation of the cellulose fibers using an N-oxyl compound as an oxidation catalyst. A method of disentangling the fibers to a nano size can be used by applying a treatment or the like.

Beating or pulverization among the above is a method for obtaining fine cellulose fibers by mechanically beating or pulverizing raw materials such as pulp by directly applying force to loosen the fibers. More specifically, for example, pulp or the like is mechanically treated with a high-pressure homogenizer or the like to loosen cellulose fibers to a fiber diameter of about 0.1 to 10 μm, and an aqueous suspension of about 0.1 to 3% by mass is prepared. Furthermore, by repeatedly grinding or crushing this with a grinder or the like, fine cellulose fibers having a fiber diameter of about 10 to 100 nm can be obtained.

The grinding or crushing treatment can be performed using, for example, a grinder "Pure Fine Mill" manufactured by Kurita Machinery Co., Ltd., or the like. This grinder is a stone grinder that pulverizes the raw material into ultrafine particles by impact, centrifugal force, and shearing force generated when the raw material passes through the gap between the upper and lower grinders. , dispersing, emulsifying and fibrillating simultaneously. The grinding or melting treatment can also be performed using an ultra-fine grinder "Super Mascolloider" manufactured by Masuko Sangyo Co., Ltd. The Super Mascolloider is a grinder that goes beyond mere pulverization and enables ultra-atomization to the extent that it feels like melting. The Super Mascolloider is a millstone-type ultra-fine grinder composed of two non-porous grindstones whose spacing can be freely adjusted. The upper grindstone is fixed and the lower grindstone rotates at high speed. The raw material put into the hopper is sent into the gap between the upper and lower grinding wheels by centrifugal force, and the raw material is gradually ground into ultrafine particles by the strong compression, shearing and rolling frictional forces generated there.

The high-temperature and high-pressure steam treatment is a method for obtaining fine cellulose fibers by exposing raw materials such as pulp to high-temperature and high-pressure steam to loosen the fibers.

Furthermore, the treatment with the phosphate or the like is performed by phosphate-esterifying the surface of the raw material such as the pulp to weaken the binding force between the cellulose fibers, and then performing a refiner treatment to unravel the fibers and make them fine. It is a processing method for obtaining cellulose fibers. For example, the raw material such as the pulp is immersed in a solution containing 50% by mass of urea and 32% by mass of phosphoric acid, and the solution is sufficiently impregnated between cellulose fibers at 60 ° C., and then heated at 180 ° C. After proceeding with phosphorylation and washing with water, it is hydrolyzed in a 3% by mass hydrochloric acid aqueous solution at 60° C. for 2 hours, washed again with water, and then in a 3% by mass aqueous sodium carbonate solution. Phosphorylation is completed by treating at room temperature for about 20 minutes, and fine cellulose fibers can be obtained by fibrillating the treated material with a refiner.

The treatment of oxidizing cellulose fibers using the N-oxyl compound as an oxidation catalyst is a method of obtaining fine cellulose fibers by oxidizing raw materials such as pulp and then pulverizing them.

First, an aqueous dispersion is prepared by dispersing natural cellulose fibers in water of about 10 to 1000 times the amount (mass basis) on the absolute dry basis using a mixer or the like. Examples of natural cellulose fibers used as raw materials for the fine cellulose fibers include wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as straw pulp and bagasse pulp, cotton pulp such as cotton lint and cotton linter, Bacterial cellulose etc. can be mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more types as appropriate. In addition, these natural cellulose fibers may be preliminarily subjected to a treatment such as beating in order to increase the surface area.

Next, an N-oxyl compound is used as an oxidation catalyst in the aqueous dispersion to oxidize the natural cellulose fibers. Such N-oxyl compounds include, for example, TEMPO (2,2,6,6-tetramethylpiperidine-N-oxyl), 4-carboxy-TEMPO, 4-acetamido-TEMPO, 4-amino-TEMPO, 4 -dimethylamino-TEMPO, 4-phosphonooxy-TEMPO, 4-hydroxy TEMPO, 4-oxy TEMPO, 4-methoxy TEMPO, 4-(2-bromoacetamido)-TEMPO, 2-azaadamantane N-oxyl, etc. A TEMPO derivative or the like having various functional groups at the C4 position can be used. The amount of these N-oxyl compounds to be added is sufficient in the catalytic amount, and can usually be in the range of 0.1 to 10% by mass on the absolute dry basis relative to the natural cellulose fiber.

In the oxidation treatment of the natural cellulose fibers, an oxidizing agent and a co-oxidizing agent are used in combination. Examples of the oxidizing agent include halogenous acid, hypohalous acid and perhalogenic acid and salts thereof, hydrogen peroxide, and perorganic acid, among which sodium hypochlorite and sodium hypobromite. Alkali metal hypohalites such as Moreover, as a co-oxidant, for example, an alkali metal bromide such as sodium bromide can be used. The amount of the oxidizing agent used is usually in the range of about 1 to 100% by mass on an absolute dry basis relative to the natural cellulose fiber, and the amount of the co-oxidizing agent is usually used relative to the natural cellulose fiber on an absolute dry basis. is in the range of about 1 to 30% by mass.

During the oxidation treatment of the natural cellulose fibers, it is preferable to maintain the pH of the aqueous dispersion in the range of 9 to 12 from the viewpoint of efficiently proceeding with the oxidation reaction. Moreover, the temperature of the aqueous dispersion during the oxidation treatment can be arbitrarily set within the range of 1 to 50° C., and the reaction can be performed even at room temperature without temperature control. The reaction time can range from 1 to 240 minutes. A penetrating agent may be added to the aqueous dispersion in order to allow the agent to permeate into the interior of the natural cellulose fibers and introduce more carboxyl groups to the fiber surfaces. Penetrants include anionic surfactants such as carboxylates, sulfates, sulfonates, and phosphates, and nonionic surfactants such as polyethylene glycol type and polyhydric alcohol type. .

After the oxidation treatment of the natural cellulose fibers, it is preferable to carry out a purification treatment for removing impurities such as unreacted oxidizing agents and various by-products contained in the aqueous dispersion prior to micronization. Specifically, for example, a method of repeatedly washing and filtering oxidized natural cellulose fibers can be used. The natural cellulose fibers obtained after the refining treatment are usually impregnated with an appropriate amount of water and subjected to a fine treatment, but if necessary, they may be dried to form fibers or powder.

Next, refinement|miniaturization of a natural cellulose process is performed in the state disperse|distributing the natural cellulose fiber refined according to necessity in solvent, such as water. The solvent as the dispersion medium used in the micronization treatment is usually preferably water, but if desired, alcohols (methanol, ethanol, isopropanol, isobutanol, sec-butanol, tert-butanol, methyl cellosolve, ethyl cellosolve, ethylene glycol, glycerin, etc.), ethers (ethylene glycol dimethyl ether, 1,4-dioxane, tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, etc.), etc. water-soluble organic solvents may be used, and mixtures thereof may also be used. The solid content concentration of the natural cellulose fibers in the dispersion of these solvents is preferably 50% by mass or less. If the solid content concentration of the natural cellulose fiber exceeds 50% by mass, it is not preferable because extremely high energy is required for dispersion. Refinement of natural cellulose processing is achieved by low-pressure homogenizers, high-pressure homogenizers, grinders, cutter mills, ball mills, jet mills, beaters, disintegrators, short-screw extruders, twin-screw extruders, ultrasonic agitators, household juicer mixers, etc. It can be done using a dispersing device.

The fine cellulose fibers obtained by the pulverization treatment can be in the form of a suspension with an adjusted solid content concentration, or in the form of a dried powder, as desired. Here, when making a suspension, only water may be used as a dispersion medium, and water and other organic solvents such as alcohols such as ethanol, surfactants, acids, bases, etc. Mixed solvents may also be used.

By the oxidation treatment and refining treatment of the natural cellulose fiber, the hydroxyl group at the C6 position of the structural unit of the cellulose molecule is selectively oxidized to the carboxyl group via the aldehyde group, and the content of the carboxyl group is reduced to 0.1. It is possible to obtain highly crystalline fine cellulose fibers having the predetermined number-average fiber diameter described above, which are composed of cellulose molecules of ˜3 mmol/g. The highly crystalline fine cellulose fibers have a cellulose type I crystal structure. This means that such fine cellulose fibers are obtained by surface-oxidizing naturally occurring cellulose molecules having a type I crystal structure and making them fine. In other words, in natural cellulose fibers, fine fibers called microfibrils produced in the biosynthetic process are bundled into multiple bundles to build a higher-order solid structure, and there is a strong cohesive force between the microfibrils (surface-to-surface ) is weakened by introducing an aldehyde group or a carboxyl group by an oxidation treatment, and then subjected to a refining treatment to obtain fine cellulose fibers. By adjusting the oxidation treatment conditions, the content of carboxyl groups can be increased or decreased to change the polarity. The average aspect ratio etc. can be controlled.

The fact that the natural cellulose fiber has the I-type crystal structure is typical at two positions near 2θ = 14 to 17° and 2θ = 22 to 23° in the diffraction profile obtained by measuring the wide-angle X-ray diffraction image. It can be identified by having a specific peak. In addition, the fact that carboxyl groups have been introduced into the cellulose molecules of the fine cellulose fibers is due to absorption (1608 cm ^-1 near) exists. In the case of carboxyl groups (COOH) there is an absorption at 1730 cm ⁻¹ in the above measurements.

Since halogen atoms are attached to or bonded to the natural cellulose fibers after the oxidation treatment, a dehalogenation treatment may be performed for the purpose of removing such residual halogen atoms. The dehalogenation treatment can be performed by immersing the natural cellulose fibers after the oxidation treatment in a hydrogen peroxide solution or an ozone solution.

Specifically, for example, natural cellulose fibers after oxidation treatment are added to a hydrogen peroxide solution having a concentration of 0.1 to 100 g/L at a bath ratio of about 1:5 to 1:100, preferably 1:10 to 1. : Immersed under the condition of about 60 (mass ratio). The concentration of the hydrogen peroxide solution in this case is preferably 1-50 g/L, more preferably 5-20 g/L. Also, the pH of the hydrogen peroxide solution is preferably 8-11, more preferably 9.5-10.7.

The amount [mmol/g] of carboxyl groups in cellulose with respect to the mass of fine cellulose fibers contained in the aqueous dispersion can be evaluated by the following method. That is, 60 ml of a 0.5 to 1% by mass aqueous dispersion of a fine cellulose fiber sample whose dry mass was precisely weighed in advance was prepared, and the pH was adjusted to about 2.5 with a 0.1 M hydrochloric acid aqueous solution. An aqueous sodium hydroxide solution is added dropwise until the pH reaches about 11, and the electrical conductivity is measured. From the amount of sodium hydroxide (V) consumed in the neutralization step of the weak acid, whose electrical conductivity changes slowly, the amount of functional groups can be determined using the following formula. The amount of functional groups indicates the amount of carboxyl groups.
Functional group amount [mmol/g] = V [ml] x 0.05/fine cellulose fiber sample [g]

Further, the fine cellulose fibers used in the present invention may be chemically and/or physically modified to enhance functionality. Here, as chemical modification, functional groups are added by acetalization, acetylation, cyanoethylation, etherification, isocyanate, etc., inorganic substances such as silicates and titanates are combined by chemical reactions, sol-gel methods, etc., Alternatively, it can be carried out by a method such as coating. As a method of chemical modification, for example, there is a method of immersing fine cellulose fibers formed into a sheet in acetic anhydride and heating. In addition, fine cellulose fibers obtained by oxidizing cellulose fibers using an N-oxyl compound as an oxidation catalyst are modified with amine compounds, quaternary ammonium compounds, etc. on the carboxyl groups in the molecule with ionic bonds or amide bonds. method.
Physical modification methods include, for example, metal and ceramic raw materials, vacuum deposition, ion plating, sputtering and other physical vapor deposition methods (PVD methods), chemical vapor deposition methods (CVD methods), electroless plating and electrolytic plating. method, etc., for coating. These modifications may be made before or after the treatment.

The number average fiber diameter of the fine cellulose fibers used in the present invention is preferably 3 nm or more and less than 100 nm. Since the minimum diameter of the fine cellulose fiber single fiber is 3 nm, it is practically impossible to produce fine cellulose fibers with a diameter of less than 3 nm. , the film formability deteriorates. The number average fiber diameter of the fine cellulose fibers can be measured according to the method for measuring the size of fine powder described above.

(cellulose nanocrystal particles)
In the present invention, the cellulose nanocrystal particles are obtained by hydrolyzing a cellulose raw material with a high-concentration mineral acid (hydrochloric acid, sulfuric acid, hydrobromic acid, etc.) to remove the non-crystalline portion and isolate only the crystalline portion. Any particles can be used. Specifically, the cellulose nanocrystal particles are prepared by adding a cellulose raw material to a strong acid of 7 wt% or more, preferably 9 wt% or more, more preferably a strong acid such as sulfuric acid that can be easily increased in concentration at a concentration of 60 wt% or more. It is a crystalline form that does not contain an amorphous part obtained by hydrolysis. By using cellulose nanocrystal particles as the fine powder, it is possible to obtain a cured product that maintains a low coefficient of thermal expansion even in a temperature range exceeding 200°C during component mounting and that is excellent in various properties such as toughness and heat resistance. It is possible to provide a curable resin composition excellent in pot life.

The cellulose nanocrystal particles preferably have an average crystal width of 3 to 70 nm and an average crystal length of 100 to 500 nm, more preferably an average crystal width of 3 to 50 nm and an average crystal length of 100 to 400 nm. More preferably, the average crystal width is 3 to 10 nm and the average crystal length is 100 to 300 nm. Here, the crystal width refers to the length of the short side of the grain, and the crystal length refers to the length of the long side of the grain. Such cellulose nanocrystal particles have a much larger surface area per unit mass and a greater proportion of atoms exposed on the surface than those with greater widths and lengths. Therefore, it is considered that the cellulose nanocrystal particles interact with each other to exert a reinforcing effect and reduce the thermal expansibility.

Here, the size of the cellulose nanocrystal particles (average crystal width, average crystal length) can be measured by SEM (Scanning Electron Microscope), TEM (Transmission Electron Microscope) or AFM (Atomic Force Microscope). ; atomic force microscope) can be observed and measured.
Specifically, a line is drawn on the diagonal line of the micrograph, 12 particles in the vicinity of the line and whose size can be measured are randomly extracted, and after removing the largest and smallest particles, the remaining The average crystal width and average crystal length of the cellulose nanocrystal particles are obtained by measuring the sizes (crystal width and crystal length) at 10 points and averaging the respective values.

As the cellulose nanocrystal particles, two or more kinds of different cellulose raw materials may be used in combination.

Such cellulose nanocrystal particles are preferably subjected to hydrophobic treatment, surface treatment using a coupling agent, or the like. For such treatment, a known and commonly used method suitable for cellulose nanocrystal particles can be used.

Examples of the cellulose raw material include paper pulp, cotton pulp such as cotton linter and cotton lint, non-wood pulp such as hemp, straw, and bagasse, and cellulose isolated from sea squirts, seaweed, and the like. It is not particularly limited. Among these, pulp for papermaking is preferable from the point of view of availability, and cotton and sea squirt are preferable from the point of being able to manufacture a CNC having excellent heat resistance.
Examples of papermaking pulp include hardwood kraft pulp and softwood kraft pulp.
Hardwood kraft pulps include bleached kraft pulp (LBKP), unbleached kraft pulp (LUKP), oxygen-bleached kraft pulp (LOKP), and the like.
Softwood kraft pulps include bleached kraft pulp (NBKP), unbleached kraft pulp (NUKP), oxygen-bleached kraft pulp (NOKP), and the like.
Other examples include chemical pulp, semi-chemical pulp, mechanical pulp, non-wood pulp, and deinked pulp made from waste paper. Chemical pulp includes sulfite pulp (SP), soda pulp (AP), and the like. Semi-chemical pulp includes semi-chemical pulp (SCP), chemigroundwood pulp (CGP), and the like. Mechanical pulp includes ground wood pulp (GP), thermomechanical pulp (TMP, BCTMP), and the like. Non-wood pulps include those made from paper mulberry, mitsumata, hemp, kenaf, and the like.
Such cellulose raw materials may be used singly or in combination of two or more. In addition, cellulose nanofibers (hereinafter also simply referred to as “CNF”) produced by a mechanical fibrillation method, a phosphoric acid esterification method, a TEMPO oxidation method, or the like may be used as the cellulose raw material.

Next, the hydrolysis of the cellulose raw material as described above can be carried out, for example, by treating an aqueous suspension or slurry containing the cellulose raw material with sulfuric acid, hydrochloric acid, hydrobromic acid, etc., or by treating the cellulose raw material as it is with sulfuric acid, hydrochloric acid, odorant, etc. It can be carried out by suspending it in an aqueous solution such as hydrochloride acid. In particular, when pulp is used as the cellulose raw material, it is preferable to hydrolyze the fibrous fiber using a cutter mill, pin mill, or the like, since it can be hydrolyzed uniformly.
In such hydrolysis treatment, the temperature conditions are not particularly limited, but can be, for example, 25 to 90°C. The conditions for the hydrolysis treatment time are also not particularly limited, but can be, for example, 10 to 120 minutes.
The cellulose nanocrystal particles obtained by hydrolyzing the cellulose raw material in this manner can be neutralized using an alkali such as sodium hydroxide.

The cellulose nanocrystal particles thus obtained can be subjected to micronization treatment if necessary. In this atomization treatment, the treatment apparatus and treatment method are not particularly limited.
Examples of atomization equipment include grinders (stone mill type grinders), high pressure homogenizers, ultra-high pressure homogenizers, high pressure impact grinders, ball mills, bead mills, disk refiners, conical refiners, twin-screw kneaders, vibration mills, high-speed A homomixer under rotation, an ultrasonic disperser, a beater, etc. can be used.

At the time of the atomization treatment, it is preferable to dilute the cellulose nanocrystal particles with water and an organic solvent alone or in combination to form a slurry, but there is no particular limitation. Preferred organic solvents include alcohols, ketones, ethers, dimethylsulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), and the like. One type of dispersion medium may be used, or two or more types may be used. In addition, the dispersion medium may contain solids other than the cellulose nanocrystal particles, such as urea having hydrogen bonding properties.

Moreover, the cellulose nanocrystal particles used in the present invention may be chemically and/or physically modified to enhance functionality. Here, as chemical modification, functional groups are added by acetalization, acetylation, cyanoethylation, etherification, isocyanate, etc., inorganic substances such as silicates and titanates are combined by chemical reactions, sol-gel methods, etc., Alternatively, it can be carried out by a method such as coating. Physical modification can be performed by plating or vapor deposition.

[Active ester compound]
An active ester compound may be used individually by 1 type, or may use 2 or more types together. The active ester compound is not particularly limited, but preferably has two or more active ester groups in one molecule. An active ester compound can generally be obtained by a condensation reaction of one or more of a carboxylic acid compound and a thiocarboxylic acid compound and one or more of a hydroxy compound and a thiol compound. Active ester compounds include dicyclopentadienyl diphenol ester compounds, bisphenol A diacetate, diphenyl phthalate, diphenyl terephthalate, bis[4-(methoxycarbonyl)phenyl] terephthalate and the like.

The content of the active ester compound is preferably 0.5% by mass or more and 80% by mass or less, more preferably 1% by mass or more and 40% by mass or less, still more preferably 1.5% by mass, based on the total amount of the composition excluding the solvent. It is more than mass % and below 30 mass %. When the blending amount of the active ester compound is 0.5% by mass or more, a low coefficient of thermal expansion can be favorably secured. On the other hand, when it is 80% by mass or less, curability is improved.

In the present invention, if desired, a curable resin such as a thermosetting resin other than the active ester compound can be used in combination.

(Thermosetting resin)
As the thermosetting resin, any resin can be used as long as it is cured by heating and exhibits electrical insulating properties. For example, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol E epoxy resin, bisphenol Bisphenol type epoxy resins such as M type epoxy resin, bisphenol P type epoxy resin, bisphenol Z type epoxy resin, bisphenol A novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, etc. Novolak type epoxy resin, biphenyl type epoxy Resins, biphenylaralkyl type epoxy resins, arylalkylene type epoxy resins, tetraphenylolethane type epoxy resins, phenoxy type epoxy resins, dicyclopentadiene type epoxy resins, norbornene type epoxy resins, adamantane type epoxy resins, fluorene type epoxy resins, glycidyl methacrylate copolymer epoxy resin, copolymer epoxy resin of cyclohexylmaleimide and glycidyl methacrylate, epoxy-modified polybutadiene rubber derivative, CTBN-modified epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, Biphenyl-4,4'-diglycidyl ether, 1,6-hexanediol diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, triglycidyl Tris(2-hydroxyethyl)isocyanurate, novolac-type phenolic resins such as phenolic novolac resin, cresol novolac resin, bisphenol A novolak resin, unmodified resol phenolic resin, oil-modified resole modified with tung oil, linseed oil, walnut oil, etc. Phenolic resins such as resol-type phenolic resins such as phenolic resins, phenoxy resins, urea (urea) resins, triazine ring-containing resins such as melamine resins, unsaturated polyester resins, bismaleimide resins, diallyl phthalate resins, silicone resins, benzoxazine rings , norbornene resins, cyanate resins, isocyanate resins, urethane resins, benzocyclobutene resins, maleimide resins, bismaleimide triazine resins, polyazomethine resins, thermosetting polyimides, and the like.

When the resin composition of the present invention is used as an alkali-developable photosolder resist that can be developed with an aqueous alkali solution, it is also preferable to use a carboxyl group-containing resin.

(Carboxyl group-containing resin)
As the carboxyl group-containing resin, both a photosensitive carboxyl group-containing resin having at least one photosensitive unsaturated double bond and a carboxyl group-containing resin having no photosensitive unsaturated double bond can be used. and is not limited to a specific one. As the carboxyl group-containing resin, particularly the resins listed below can be preferably used.
(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid and a compound having an unsaturated double bond, and a carboxyl group-containing resin obtained by modifying it to adjust the molecular weight and acid value.
(2) A photosensitive carboxyl group-containing resin obtained by reacting a carboxyl group-containing (meth)acrylic copolymer resin with a compound having an oxirane ring and an ethylenically unsaturated group in one molecule.
(3) reacting an unsaturated monocarboxylic acid with a copolymer of a compound having one epoxy group and an unsaturated double bond in one molecule and a compound having an unsaturated double bond, and produced by this reaction A photosensitive carboxyl group-containing resin obtained by reacting a saturated or unsaturated polybasic acid anhydride with a secondary hydroxyl group.
(4) After reacting a hydroxyl group-containing polymer with a saturated or unsaturated polybasic acid anhydride, a compound having one epoxy group and an unsaturated double bond in each molecule is added to the carboxylic acid produced by this reaction. A photosensitive hydroxyl group- and carboxyl group-containing resin obtained by a reaction.
(5) A photosensitive carboxyl group obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting some or all of the secondary hydroxyl groups generated by this reaction with a polybasic acid anhydride. Contained resin.
(6) reacting a polyfunctional epoxy compound, a compound having two or more hydroxyl groups in one molecule and one reactive group other than a hydroxyl group that reacts with the epoxy group, and an unsaturated group-containing monocarboxylic acid to obtain A carboxyl group-containing photosensitive resin obtained by reacting the obtained reaction product with a polybasic acid anhydride.
(7) Obtained by reacting an unsaturated group-containing monocarboxylic acid with a reaction product of a resin having a phenolic hydroxyl group and an alkylene oxide or a cyclic carbonate, and reacting the resulting reaction product with a polybasic acid anhydride. Carboxyl group-containing photosensitive resin.
(8) a reaction product obtained by reacting a polyfunctional epoxy compound, a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, and an unsaturated group-containing monocarboxylic acid; A carboxyl group-containing photosensitive resin obtained by reacting an anhydride group of a polybasic acid anhydride with an alcoholic hydroxyl group of the above.

[Filler]
The resin composition of the present invention preferably further contains a filler other than the fine powder. Examples of fillers include barium sulfate, barium titanate, amorphous silica, crystalline silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, and aluminum nitride. be done. Among these fillers, silica, especially spherical silica, is preferred because it has a small specific gravity, can be blended in a composition at a high proportion, and is excellent in low thermal expansion properties. The average particle size of the filler is preferably 3 μm or less, more preferably 1 μm or less. The average particle size of the filler can be determined using a laser diffraction particle size distribution analyzer.

The amount of filler compounded is 1 to 90% by mass, preferably 2 to 80% by mass, more preferably 5 to 75% by mass of the total amount of the composition excluding the solvent. By setting the blending amount of the filler within the above range, it is possible to ensure good coating performance of the cured product after curing.

The resin composition of the present invention may further contain other commonly used ingredients as appropriate, depending on its use. Other conventional compounding ingredients include, for example, curing catalysts, colorants, organic solvents, and the like.

As a curing catalyst, phenolic compounds; Imidazole derivatives such as (2-cyanoethyl)-2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzyl amines, amine compounds such as 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. In addition, commercially available products include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (manufactured by Shikoku Chemical Industry Co., Ltd.), U-CAT3503N, U-CAT3502T, DBU, DBN, U-CATSA102, U- CAT5002 (manufactured by San-Apro Co., Ltd.), etc., may be used alone or in combination of two or more. Similarly, guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6 S-triazine derivatives such as -diamino-S-triazine/isocyanuric acid adduct and 2,4-diamino-6-methacryloyloxyethyl-S-triazine/isocyanuric acid adduct can also be used.

In the present invention, among others, phenol compounds are preferably used. Examples of phenolic compounds include phenol novolak resins, alkylphenol novolak resins, triazine structure-containing novolak resins, bisphenol A novolak resins, dicyclopentadiene type phenol resins, Zyloc type phenol resins, copna resins, terpene-modified phenol resins, polyvinyl phenols, and the like. phenol compounds, naphthalene-based curing agents, fluorene-based curing agents, and the like can be used alone or in combination of two or more. Examples of the phenol compounds include HE-610C and 620C manufactured by Air Water Inc., TD-2131, TD-2106, TD-2093, TD-2091, TD-2090 and VH-4150 manufactured by DIC Corporation, VH-4170, KH-6021, KA-1160, KA-1163, KA-1165, TD-2093-60M, TD-2090-60M, LF-6161, LF-4871, LA-7052, LA-7054, LA- 7751, LA-1356, LA-3018-50P, EXB-9854, Nippon Steel & Sumikin Chemical Co., Ltd. SN-170, SN180, SN190, SN475, SN485, SN495, SN375, SN395, JX Nippon Oil & Energy Corporation DPP manufactured by Meiwa Kasei Co., Ltd. HF-1M, HF-3M, HF-4M, H-4, DL-92, MEH-7500, MEH-7600-4H, MEH-7800, MEH-7851, MEH -7851-4H, MEH-8000H, MEH-8005, XL, XLC, RN, RS, RX manufactured by Mitsui Chemicals, Inc., but not limited thereto. These phenol compounds can be used alone or in combination of two or more.

The amount of the curing catalyst used in the present invention is sufficient at a ratio normally used. 100 parts by mass, more preferably 10 to 50 parts by mass, and in the case of other curing catalysts, 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass Department.

As the coloring agent, commonly known coloring agents such as red, blue, green and yellow can be used, and any of pigments, dyes and pigments can be used. However, it is preferable not to contain halogen from the viewpoint of environmental load reduction and influence on the human body.

Blue colorant:
Blue colorants include phthalocyanines and anthraquinones, and pigments are compounds classified as pigments. (published by The Society of Dyers and Colourists), which may be numbered: Pigment Blue 15, Pigment Blue 15:1, Pigment Blue 15:2, Pigment Blue 15:3, Pigment Blue 15:4 , Pigment Blue 15:6, Pigment Blue 16, Pigment Blue 60.
染料系としては、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ３５、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ６３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ６８、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ７０、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ８３、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ８７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ９４、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ９７、Ｓｏｌｖｅｎｔ Ｂｌｕｅ １２２、Ｓｏｌｖｅｎｔ Ｂｌｕｅ １３６、Ｓｏｌｖｅｎｔ Ｂｌｕｅ ６７、Ｓｏｌｖｅｎｔ Blue 70 or the like can be used. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Green colorant:
As the green coloring agent, there are similarly phthalocyanine-based and anthraquinone-based coloring agents, and specifically Pigment Green 7, Pigment Green 36, Solvent Green 3, Solvent Green 5, Solvent Green 20, Solvent Green 28, etc. can be used. . In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

Yellow colorant:
Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone colorants, and specific examples thereof include the following.
Anthraquinone series: Solvent Yellow 163, Pigment Yellow 24, Pigment Yellow 108, Pigment Yellow 193, Pigment Yellow 147, Pigment Yellow 199, Pigment Yellow 202.
Isoindolinone series: Pigment Yellow 110, Pigment Yellow 109, Pigment Yellow 139, Pigment Yellow 179, Pigment Yellow 185.
Condensed azo series: Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128, Pigment Yellow 155, Pigment Yellow 166, Pigment Yellow 180.
Benzimidazolone series: Pigment Yellow 120, Pigment Yellow 151, Pigment Yellow 154, Pigment Yellow 156, Pigment Yellow 175, Pigment Yellow 181.
Monoazo series: Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62: 1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116 , 167, 168, 169, 182, 183.
Disazo series: Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198.

Red colorant:
Examples of red colorants include monoazo, disazo, azo lake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone colorants. be done.
Monoazo type: Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151 , 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269.
Disazo series: Pigment Red 37, 38, 41.
Monoazo lake system: Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57 : 1, 58: 4, 63: 1, 63: 2, 64: 1, 68.
Benzimidazolone series: Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185, Pigment Red 208.
Perylene series: Solvent Red 135, Solvent Red 179, Pigment Red 123, Pigment Red 149, Pigment Red 166, Pigment Red 178, Pigment Red 179, Pigment Red 190, Pigment Red 194, Pigment Red 224.
Diketopyrrolopyrrole series: Pigment Red 254, Pigment Red 255, Pigment Red 264, Pigment Red 270, Pigment Red 272.
Condensed azo systems: Pigment Red 220, Pigment Red 144, Pigment Red 166, Pigment Red 214, Pigment Red 220, Pigment Red 221, Pigment Red 242.
Anthraquinone series: Pigment Red 168, Pigment Red 177, Pigment Red 216, Solvent Red 149, Solvent Red 150, Solvent Red 52, Solvent Red 207.
Quinacridones: Pigment Red 122, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209.

In addition, coloring agents such as purple, orange, brown and black may be added for the purpose of adjusting the color tone.
Specific examples include Pigment Violet 19, 23, 29, 32, 36, 38, 42, Solvent Violet 13, 36, C.I. I. Pigment Orange 1, C.I. I. Pigment Orange 5, C.I. I. Pigment Orange 13, C.I. I. Pigment Orange 14, C.I. I. Pigment Orange 16, C.I. I. Pigment Orange 17, C.I. I. Pigment Orange 24, C.I. I. Pigment Orange 34, C.I. I. Pigment Orange 36, C.I. I. Pigment Orange 38, C.I. I. Pigment Orange 40, C.I. I. Pigment Orange 43, C.I. I. Pigment Orange 46, C.I. I. Pigment Orange 49, C.I. I. Pigment Orange 51, C.I. I. Pigment Orange 61, C.I. I. Pigment Orange 63, C.I. I. Pigment Orange 64, C.I. I. Pigment Orange 71, C.I. I. Pigment Orange 73, C.I. I. Pigment Brown 23, C.I. I. Pigment Brown 25, C.I. I. Pigment Black 1, C.I. I. Pigment Black 7, etc.

A specific mixing ratio of the coloring agent can be appropriately adjusted depending on the type of coloring agent used and the type of other additives.

Examples of organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, and diethylene glycol. Glycol ethers such as monoethyl ether, dipropylene glycol monoethyl ether and triethylene glycol monoethyl ether; Esters such as ethyl acetate, butyl acetate, cellosolve acetate, diethylene glycol monoethyl ether acetate and esters of the above glycol ethers; Alcohols such as ethanol, propanol, ethylene glycol and propylene glycol; aliphatic hydrocarbons such as octane and decane; and petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha and solvent naphtha.

In addition, known and commonly used additives such as antifoaming agents/leveling agents, thixotropy-imparting agents/thickening agents, coupling agents, dispersants, and flame retardants can be added as necessary.

The curable resin composition of the present invention may be used as a dry film, or may be used as a liquid. The curable resin composition of the present invention can also be used as a prepreg, which is obtained by coating or impregnating a sheet-like fibrous base material such as glass cloth, glass or aramid non-woven fabric and semi-curing it. When used as a liquid, it may be one-liquid or two-liquid or more. As a two-liquid composition, for example, a composition in which fine cellulose fibers and an active ester compound are separated may be used.

The dry film of the present invention has a resin layer obtained by coating and drying the curable resin composition of the present invention on a carrier film. When forming a dry film, first, the curable resin composition of the present invention is diluted with the above organic solvent to adjust the viscosity to an appropriate value, and then a comma coater, blade coater, lip coater, rod coater, and squeeze coater are used. , a reverse coater, a transfer roll coater, a gravure coater, a spray coater, or the like to a uniform thickness on the carrier film. After that, the applied composition is usually dried at a temperature of 40 to 130° C. for 1 to 30 minutes to form a resin layer. The coating thickness is not particularly limited, but is generally selected as appropriate in the range of 3 to 150 μm, preferably 5 to 60 μm, in terms of thickness after drying.

As the carrier film, a plastic film is used, and for example, a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, a polystyrene film, or the like can be used. The thickness of the carrier film is not particularly limited, but is generally selected appropriately within the range of 10 to 150 μm. More preferably, it is in the range of 15 to 130 μm.

After forming the resin layer composed of the curable resin composition of the present invention on the carrier film, for the purpose of preventing dust from adhering to the surface of the resin layer, a peelable cover is further placed on the surface of the resin layer. It is preferred to laminate the films. As the peelable cover film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, or the like can be used. Any cover film may be used as long as the adhesive force between the cover film and the resin layer is smaller than the adhesive force between the resin layer and the carrier film when the cover film is peeled off.

In the present invention, the curable resin composition of the present invention may be coated on the cover film and dried to form a resin layer, and a carrier film may be laminated on the surface of the resin layer. That is, either a carrier film or a cover film may be used as the film to which the curable resin composition of the present invention is applied when producing the dry film in the present invention.

The cured product of the present invention is obtained by curing the curable resin composition of the present invention or the resin layer of the dry film of the present invention.

The electronic component of the present invention comprises the cured product of the present invention, and specific examples thereof include printed wiring boards. The cured product of the present invention can be suitably used in electronic parts that require insulation reliability between layers. In particular, a multilayer printed wiring board using the resin composition of the present invention as an interlayer insulating material can have good interlayer insulation reliability.

FIG. 1 shows a partial cross-sectional view showing one structural example of a multilayer printed wiring board according to one example of the electronic component of the present invention. The illustrated multilayer printed wiring board can be manufactured, for example, as follows. First, a through hole is formed in the core substrate 2 on which the conductor pattern 1 is formed. Formation of the through-holes can be performed by appropriate means such as drilling, die punching, and laser light. After that, a roughening treatment is performed using a roughening agent. In general, the roughening treatment is carried out by swelling with an organic solvent such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, methoxypropanol, or an alkaline aqueous solution such as caustic soda, caustic potash, etc., followed by dichromate, permanganate. It is carried out using an oxidizing agent such as salt, ozone, hydrogen peroxide/sulfuric acid, nitric acid.

Next, the conductor pattern 3 is formed by a combination of electroless plating and electrolytic plating. The step of forming a conductor layer by electroless plating is a step of immersing the substrate in an aqueous solution containing a plating catalyst to adsorb the catalyst and then immersing the substrate in a plating solution to deposit plating. A predetermined circuit pattern is formed on the conductor layer on the surface of the core substrate 2 according to a conventional method (subtractive method, semi-additive method, etc.), and as shown in the figure, conductor patterns 3 are formed on both sides. At this time, a plated layer is also formed in the through hole, and as a result, the connection portion 4 of the conductor pattern 3 of the multilayer printed wiring board and the connection portion 1a of the conductor pattern 1 are electrically connected. , through holes 5 are formed.

Next, an appropriate method such as screen printing, spray coating, or curtain coating is used to apply, for example, a thermosetting composition, followed by heat curing to form the interlayer insulating layer 6 . When a dry film or prepreg is used, the interlayer insulating layer 6 is formed by lamination or hot plate pressing and heat curing. Next, vias 7 for electrically connecting connection portions of each conductor layer are formed by suitable means such as laser light, and conductor patterns 8 are formed in the same manner as the conductor patterns 3 described above. Furthermore, an interlayer insulating layer 9, vias 10 and conductor patterns 11 are formed in a similar manner. After that, a multilayer printed wiring board is manufactured by forming a solder resist layer 12 as the outermost layer. In the above, an example in which an interlayer insulating layer and a conductor layer are formed on a laminated substrate has been described, but a single-sided substrate or a double-sided substrate may be used instead of the laminated substrate.

The present invention will now be described in more detail using examples.
[Preparation of fine cellulose fibers]
Production Example 1 (CNF1)
After sufficiently stirring softwood bleached kraft pulp fiber (650 ml of Machenzie CSF manufactured by Fletcher Challenge Canada) with 9900 g of ion-exchanged water, TEMPO (2,2,6,6-tetramethyl Piperidine 1-oxyl free radical) 1.25% by weight, sodium bromide 12.5% by weight and sodium hypochlorite 28.4% by weight were added in this order. Using a pH stud, the pH was maintained at 10.5 by dropwise addition of 0.5M sodium hydroxide. After the reaction was carried out for 120 minutes (20° C.), the dropwise addition of sodium hydroxide was stopped to obtain oxidized pulp. The obtained oxidized pulp was thoroughly washed with ion-exchanged water and then dehydrated. After that, 3.9 g of oxidized pulp and 296.1 g of ion-exchanged water were subjected to refining treatment twice at 245 MPa using a high-pressure homogenizer (Starburst Lab HJP-2 5005, manufactured by Sugino Machine Co., Ltd.) to obtain fine cellulose fibers containing carboxyl groups. A dispersion liquid (solid concentration: 1.3% by mass) was obtained.

Next, 4088.75 g of the resulting carboxyl group-containing fine cellulose fiber dispersion liquid was placed in a beaker, 4085 g of ion-exchanged water was added to make a 0.5% by mass aqueous solution, and the mixture was stirred with a mechanical stirrer at room temperature (25°C) for 30 minutes. Stirred. Subsequently, 245 g of 1M hydrochloric acid aqueous solution was charged and reacted at room temperature for 1 hour. After completion of the reaction, the precipitate was reprecipitated with acetone, filtered, and then washed with acetone/ion-exchanged water to remove hydrochloric acid and salts. Finally, acetone was added and filtered to obtain an acetone-containing acid-type cellulose fiber dispersion (solid concentration: 5.0% by mass) in which the carboxyl group-containing fine cellulose fibers were swollen in acetone. After completion of the reaction, it was filtered and then washed with ion-exchanged water to remove hydrochloric acid and salts. After replacing the solvent with acetone, the solvent was replaced with DMF, and a DMF-containing acid-type cellulose fiber dispersion (average fiber diameter 3.3 nm, solid content concentration 5.0% by mass) in which the carboxyl group-containing fine cellulose fibers were swollen was prepared. Obtained.

Production Example 2 (CNF2)
40 g of the DMF-containing acid-type cellulose fiber dispersion obtained in Production Example 1 and 0.3 g of hexylamine were placed in a beaker equipped with a magnetic stirrer and stirrer, and dissolved in 300 g of ethanol. The reaction solution was reacted at room temperature (25° C.) for 6 hours. After completion of the reaction, the mixture was filtered, washed with DMF, and the solvent was replaced to obtain a fine cellulose fiber composite (solid concentration: 5.0% by mass) in which amines were linked to the fine cellulose fibers via ionic bonds.
The CNF produced by the method of Production Example 2 has particularly good dispersibility, and can be dispersed by a general method without using a special dispersing machine such as a high-pressure homogenizer.

Production Example 3 (CNF3)
10% by mass of fine cellulose fibers (BiNFi-s manufactured by Sugino Machine, average fiber diameter 80 nm) was dehydrated and filtered, 10 times the amount of carbitol acetate was added to the filtered material, and the mixture was stirred for 30 minutes and then filtered. This replacement operation was repeated three times, and carbitol acetate was added in an amount 20 times the amount of the filter material to prepare a fine cellulose fiber dispersion (solid concentration: 5.0% by mass).

[Preparation of cellulose nanocrystal particles]
Production example 4 (CNC1)
A paper sheet of dried softwood bleached kraft pulp was processed with a cutter mill and a pin mill to obtain cotton-like fibers. 100 g of this cotton-like fiber was taken in absolute dry mass, suspended in 2 L of a 64% sulfuric acid aqueous solution, and hydrolyzed at 45° C. for 45 minutes.

After the resulting suspension was filtered, 10 L of ion-exchanged water was poured into the suspension and stirred to uniformly disperse the suspension to obtain a dispersion. Then, the step of filtering and dehydrating the dispersion was repeated three times to obtain a dehydrated sheet. Next, the obtained dehydrated sheet was diluted with 10 L of ion-exchanged water, and 1N sodium hydroxide aqueous solution was added little by little while stirring to adjust the pH to about 12. Thereafter, this suspension was filtered and dehydrated, and the process of adding 10 L of ion-exchanged water, stirring, and filtering and dehydrating was repeated twice.

Then, deionized water was added to the obtained dehydrated sheet to prepare a 2% suspension. This suspension was passed through a wet atomization device ("Ultimizer" manufactured by Sugino Machine Co., Ltd.) 10 times at a pressure of 245 MPa to obtain an aqueous dispersion of cellulose nanocrystal particles.

Thereafter, the solvent was replaced with acetone and then with DMF to obtain a DMF dispersion (solid concentration: 5.0% by mass) in which the cellulose nanocrystal particles were swollen. As a result of observing and measuring the cellulose nanocrystal particles in the obtained dispersion by AFM, the average crystal width was 10 nm and the average crystal length was 200 nm.

Production example 5 (CNC2)
A DMF dispersion of swollen cellulose nanocrystal particles (solid content concentration: 5.0% by mass) was obtained in the same manner as in Production Example 4, except that absorbent cotton (manufactured by Hakujuji Co., Ltd.) was used as the cellulose raw material. rice field. As a result of observing and measuring the cellulose nanocrystal particles in the obtained dispersion by AFM, the average crystal width was 7 nm and the average crystal length was 150 nm.

According to the description in Tables 1 to 4 below, each component was blended and stirred, and then dispersed repeatedly six times using a high-pressure homogenizer Nanovater NVL-ES008 manufactured by Yoshida Kikai Kogyo Co., Ltd. to prepare each composition. The numerical values in Tables 1 to 4 indicate parts by mass.

[Thermal expansion coefficient measurement]
Each composition was applied to a PET film having a thickness of 38 μm using an applicator with a gap of 120 μm, and dried in a hot air circulating drying oven at 90° C. for 10 minutes to obtain a dry film having a resin layer of each composition. Thereafter, the resin layer of each composition was laminated by pressure bonding with a vacuum laminator at 60° C. and a pressure of 0.5 MPa for 60 seconds to a copper foil having a thickness of 18 μm, and the PET film was peeled off. Then, the film was cured by heating at 180° C. for 30 minutes in a hot air circulating drying oven, and the copper foil was peeled off to obtain a cured film sample. The prepared sample for thermal expansion measurement was cut into 3 mm width×30 mm length. This test piece is subjected to tension mode using TMA (Thermomechanical Analysis) Q400 manufactured by TA Instruments Co., Ltd., a chuck distance of 16 mm, a load of 30 mN, under a nitrogen atmosphere, from 20 to 250 ° C. at 5 ° C./min. It was warmed and then cooled to 250-20°C at a rate of 5°C/min and measured. The coefficient of thermal expansion (ppm/K) was obtained at 25° C. and 200° C. when the temperature was lowered. The temperature at which the coefficient of thermal expansion abruptly changes was defined as Tg (glass transition point). The results are shown in Tables 1-4.

[Dielectric constant, dielectric loss tangent]
Each composition was applied to a PET film having a thickness of 38 μm using an applicator with a gap of 200 μm, and dried in a hot air circulating drying oven at 90° C. for 20 minutes to obtain a dry film having a resin layer of each composition. After that, an electrolytic copper foil with a thickness of 18 μm was fixed with tape to a FR-4 copper clad laminate with a thickness of 1.6 mm with the glossy side facing upwards. The resin layer of each composition was laminated by pressure bonding under the conditions for 60 seconds, the PET film was peeled off, and the laminate was cured by heating at 180° C. for 30 minutes in a hot air circulating drying oven. Then, the fixed tape was peeled off, the electrolytic copper foil was peeled off, and a size of 1.7 mm×100 mm was cut out to obtain a sample for evaluation. The measurement was performed with a network analyzer E-507 manufactured by Keysight Technologies using a cavity resonator (5 GHz) manufactured by Kanto Denshi Applied Development Co., Ltd. For the evaluation of the relative dielectric constant, the average value of less than 2.8 measured three times was evaluated as ⊚, the average value of 2.8 or more and less than 3.0 was evaluated as ◯, and the average value of 3.0 or more was evaluated as ×. For the evaluation of the dielectric loss tangent, an average value of less than 0.02 measured three times was evaluated as ○, and an average value of 0.02 or more was evaluated as ×. The respective results are shown in Tables 1-4.

[Solder heat resistance]
On an FR-4 copper-clad laminate having a size of 150 mm x 95 mm and a thickness of 1.6 mm, a solid pattern was formed on the entire surface of each composition by 80-mesh Tetron bias plate screen printing, and dried in a hot air circulation drying oven at 80°C for 30 minutes. It was dried and then cured by heating at 180° C. for 30 minutes to obtain a test piece. A rosin-based flux was applied to the side of the cured composition of this test piece, flowed to a solder layer at 260° C. for 60 seconds, washed with propylene glycol monomethyl ether acetate, and then washed with ethanol. The test piece was visually observed for swelling and peeling of the coating film and changes in the surface condition. When abnormalities such as blistering, peeling, surface dissolution or softening were observed in the coating film, it was evaluated as x, and when it was not observed, it was evaluated as ○. The evaluation results are shown in Tables 1-4.

[Insulation]
Each composition was applied to a PET film having a thickness of 38 μm using an applicator with a gap of 120 μm, and dried in a hot air circulating drying oven at 90° C. for 10 minutes to obtain a dry film having a resin layer of each composition. After that, it was crimped for 60 seconds on the A coupon of IPC MULTI-PURPOSE TEST BOARD B-25 formed with a copper thickness of 35 μm on a 1.6 mm thick FR-4 substrate at 60° C. and a pressure of 0.5 MPa with a vacuum laminator. Then, the resin layer of each composition was laminated, the PET film was peeled off, and the laminate was cured by heating at 180° C. for 30 minutes in a hot air circulating drying oven. Next, the lower end of the IPC MULTI-PURPOSE TEST BOARD B-25 was cut to form an electrically independent terminal (cut along the dotted line in FIG. 2). A bias of DC 500 V was applied so that the upper portion of the A coupon became the cathode and the lower portion became the anode, and the insulation resistance value was measured. In the evaluation, the insulation resistance value of 100 GΩ or more was evaluated as ◯, and the insulation resistance value of less than 100 GΩ was evaluated as x. The results are shown in Tables 1-4.

*1) Thermosetting resin 1: Epiclon HP-7200 Cyclohexanone varnish with a solid content of 50% by mass (a cyclic ether compound with a dicyclopentadiene skeleton)
*2) Thermosetting resin 2: Epiclon N-740, manufactured by DIC Corporation, cyclohexanone varnish with a solid content of 50% by mass *3) Thermosetting resin 3: Epiclon 830, manufactured by DIC Corporation *4) Thermosetting resin 4 : JER827 manufactured by Mitsubishi Chemical Corporation *5) Thermosetting resin 5: Bisphenol A diacetate manufactured by Tokyo Chemical Industry Co., Ltd. (active ester)
*6) Thermosetting resin 6: Epiclon HPC-8000-65T manufactured by DIC Corporation (active ester, solid content 65% by mass)
* 7) Thermosetting resin 7: HF-1 Meiwa Kasei Co., Ltd. solid content 60% by mass cyclohexanone varnish * 8) Curing catalyst 1: 2E4MZ (2-ethyl-4-methylimidazole) Shikoku Kasei Kogyo Co., Ltd. *9) Filler 1: ADMAFINE SO-C2 Admatechs Co., Ltd. (Silica) Average particle size 0.4 to 0.6 μm
* 10) Organic solvent 1: dimethylformamide * 11) Defoamer 1: BYK-352 BYK-Chemie Japan Co., Ltd.

*12) Filler 2: B-30 Barium sulfate manufactured by Sakai Chemical Industry Co., Ltd. *13) Filler 3: DAW-07 Alumina manufactured by Denka Co., Ltd. *14) Dispersant 1: DISPERBYK-111 manufactured by BYK Chemie

As is clear from the results shown in Tables 1 to 4, by containing fine powder such as fine cellulose fibers and cellulose nanocrystal particles and an active ester compound, not only normal temperature but also high temperature range during component mounting can be achieved. However, it was confirmed that a curable resin composition that can maintain a low coefficient of thermal expansion and has low dielectric properties can be obtained. Moreover, it was confirmed from the results of the evaluation of solder heat resistance that each composition of Examples was excellent in heat resistance and chemical resistance and could be used as a composition for wiring boards.

1, 3, 8, 11 conductor pattern 2 core substrate 1a, 4 connection part 5 through hole 6, 9 interlayer insulating layer 7, 10 via 12 solder resist layer

Claims (5)

comprising a fine powder having at least one dimension smaller than 100 nm, an active ester compound, and an epoxy resin ;
A curable resin composition, wherein the fine powder contains at least one of fine cellulose fibers and cellulose nanocrystal particles. The curable resin composition according to claim 1, further comprising a filler. A dry film comprising a resin layer formed by coating and drying the curable resin composition according to claim 1 on a film. A cured product obtained by curing the curable resin composition according to claim 1 or the resin layer of the dry film according to claim 3. An electronic component comprising the cured product according to claim 4 .

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