TW202409731A - Resin composition, dry film, cured product, and electronic component - Google Patents

Abstract

Provided are resin compositions that have both low warping and high reflectivity after a reflow step. The resin composition is characterized in that it comprises (A) a carboxyl-containing urethane resin and (E) a white coloring agent, and in a dynamic viscoelasticity measurement at a frequency of 1 Hz, the loss tangent peak temperature (Tg) of the cured coating is below 100°C, and the loss tangent peak is in the range of 0.5 to 1.5.

Description

Resin compositions, dry films, hardened materials and electronic parts

The present invention relates to resin compositions, dry films, cured products and electronic parts.

In recent years, the use of low-power light-emitting diodes (LEDs) for backlights or light sources of lighting equipment directly mounted on printed circuit boards such as portable terminals, computers, and televisions has gradually increased. In order to more efficiently utilize the light of the LED, printed circuit boards used for such purposes require a solder resist film with high reflectivity and the ability to increase the overall illumination when the LED is mounted on the printed circuit board. Patent documents 1 to 4 disclose white curable resin compositions that can be used for such solder resist films. [Prior technical document] [Patent document]

Patent Document 1: Japanese Patent Application Publication No. 2009-149878 Patent document 2: Patent No. 4538521 Patent document 3: Patent No. 4538484 Patent document 4: Patent No. 4340272

[The problem that the invention wants to solve]

A liquid crystal display is composed of a light attenuator, which is a combination of liquid crystal and a polarizing film that changes the polarization state by applying a voltage, and a backlight module placed behind it. In conventional LCD displays, backlight modules have been used for a long time to emit light uniformly across the entire surface, using a split driving method that divides light-emitting areas according to the light and dark of the background, and area dimming that only lights up LEDs where brightness is required. (Local dimming) technology combination to improve contrast enhancement technology development is in progress. In the split drive method, a light guide plate is used to guide the light of LEDs arranged at the edge of the screen to an edge-lit (edge) LED backlight of the entire screen. This is achieved by mounting the LED on the back (directly below) of the screen. The number of divisions is from The latter has been commercialized between ten and 100 years ago. When the division number is small, light leaks into areas that are supposed to be dark, causing a halo effect that blurs the outline of bright areas, making it impossible to obtain sufficient image beauty. Therefore, in recent years, from the perspective of improving contrast, direct-type mini LED backlights have been proposed in which mini LEDs are reduced in size to about 1 mm or less and arranged to cover a substrate. In order to increase the number of Mini LEDs installed in the backlight module, increase the circuit density, and realize a thin backlight, it is expected that in addition to the conventionally used PCB substrates such as FR4, it is expected that TFTs can be easily installed on a flat surface in the future. Opportunities for glass substrates that can easily implement active matrix structures and flexible substrates (FPCs) that can contribute to curved surface realization and thinning will also increase. When manufacturing such a direct-type LED backlight module, a white photosensitive resin composition with insulation and high reflectivity is coated on the entire surface of the above-mentioned glass substrate, and through the steps of exposure, development, and thermal hardening, or the white The thermosetting resin composition is screen-printed using a pattern with openings only at the position where the Mini LED is installed, and through the thermosetting step, a pattern in which the Mini LED is installed is formed. After that, through the reflow step, in order to solder the Mini LED to the opening of the formed pattern, the heat step is performed again. For the direct-type LED backlight module described above, for example, in order to produce multiple chamfers for use in large liquid crystal displays or small displays, the glass substrate for the backlight has become, for example, the size of the 8th generation (2160mm×2460mm). Therefore, when the above-mentioned Mini LED installation pattern is formed using a white photosensitive resin composition or a white thermosetting resin composition having insulating properties and high reflectivity, the area of the glass substrate coated with these resin compositions is also increase. Furthermore, in order to reduce the thickness and weight of displays, the glass substrate itself has also been thinned from about 3mm in the past to 0.7mm and 0.5mm below 1mm. Due to such an increase in the coating area and the thinning of the glass, the white photosensitive resin composition or the white thermosetting resin composition shrinks due to heating in each step during pattern formation and in the subsequent reflow step. There is a problem with glass substrates becoming prone to warping. As mentioned above, the conventional white photosensitive resin composition or white thermosetting resin composition used in the backlight module of the display cannot cope with the thinning and weight reduction of the display due to the warping of the substrate after the reflow step. Waiting questions. In addition, the backlight application of displays also requires the maintenance of high reflectivity after the reflow step. It is difficult for conventional white photosensitive resin compositions or white thermosetting resin compositions to have both low warpage and high reflectivity after the reflow step. High reflectivity problem.

The present invention was completed in view of the problems of such conventional technologies, and its object is to provide a resin composition that can have both low warpage and high reflectivity after the reflow step, and a dry film, a cured product and a resin composition using the same. Electronic parts. [Means used to solve problems]

The inventors of the present invention have made efforts to achieve the above object. As a result, they found that by using a composition with specific properties in the dynamic viscoelasticity measurement at a frequency of 1 Hz of the cured coating, it was possible to achieve both high reflectivity and low warpage after the reflow step, thus solving the above-mentioned problems. subject, and completed the present invention.

That is, the resin composition of the present invention is a resin composition containing (A) a carboxyl group-containing urethane resin and (E) a white coloring agent, and is characterized in that the cured coating film has a frequency of 1 Hz. In the dynamic viscoelasticity measurement, the temperature of the loss tangent (tanδ) peak (glass transition temperature, hereinafter referred to as Tg) is 100°C or less, and the loss tangent peak is in the range of 0.5 to 1.5. Furthermore, the dynamic viscoelasticity measurement in the present invention refers to a dynamic viscoelasticity measurement device (DMA, manufactured by TA Instruments Japan Co., Ltd., model: RSA-G2), with a temperature range of -60°C to 300°C and a heating rate of Measured under the conditions of 5℃/min and frequency 1Hz. The details of the method for measuring the peaks of Tg and loss tangent (tanδ) are as follows.

When the resin composition is a photosensitive resin composition, the photosensitive resin composition is applied to the copper foil by screen printing in a manner that the film thickness after drying is 30 μm to form a resin layer. After that, the resin layer is dried in a hot air circulation drying oven at 80°C for 30 minutes, and then exposed with an exposure amount of 900 mJ/ ^cm2 using an exposure device equipped with a metal halogen lamp (HMW-680-GW20: ORC MANUFACTURING (Co., Ltd.)), and developed (30°C, 0.2 MPa, 1 mass% _{Na2CO3 aqueous} solution) for 60 seconds. Afterwards, the resin layer was cured in a hot air circulation drying oven at 150°C for 60 minutes to form a cured coating film of the resin layer, thereby manufacturing an evaluation substrate.

Furthermore, when the resin composition is a thermosetting resin composition, the thermosetting resin composition is applied to the copper foil by screen printing in a manner that the film thickness after drying is 30 μm to form a resin layer. Thereafter, the resin layer is cured in a hot air circulation drying furnace at 150°C for 60 minutes to form a cured coating of the resin layer, thereby preparing an evaluation substrate.

The peak values of Tg and loss tangent (tan δ) were obtained by peeling off the cured coating film of the resin layer formed on the evaluation substrate from the copper foil, and measuring the cured coating film with a dynamic viscoelasticity measuring device (DMA, TA Instruments Japan Co., Ltd., model number: RSA-G2) was measured in the tensile mode. The measurement conditions are a temperature range of -60°C to 300°C, a heating rate of 5°C/min, a frequency of 1Hz, a strain of 0.1%, and a sample size of 5mm width × 50mm length. The hardened coating film is provided so as to be fixed at both ends in the width direction, and the hardened coating film protruding from the chuck is cut off. The distance between the chucks is set to 10mm.

In the resin composition of the present invention, it is preferred that (E) the white coloring agent is titanium oxide, and further, it is preferred that (A) the carboxyl group-containing urethane resin contains a carboxyl group-containing amine group that does not have an aromatic ring. Ethyl formate resin, further preferably contains (D) epoxy resin. Furthermore, it is preferable to contain (F) other carboxyl group-containing resins other than (A) carboxyl group-containing urethane resin. When the resin composition of the present invention is a photosensitive resin composition, it is preferable to contain (B) a difunctional (meth)acrylate and (C) a photopolymerization initiator. Here, in the present invention, (meth)acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expression methods.

The dry film of the present invention is characterized by having a resin layer obtained by applying the resin composition of the present invention to a film and drying it. Furthermore, the cured product of the present invention is characterized by being obtained from the resin composition of the present invention or the dry film of the present invention. Furthermore, the electronic component of the present invention is characterized by having the cured product of the present invention. [Effects of the invention]

According to the present invention, a resin composition having low warp and high reflectivity after a heat treatment step, a dry film, a cured product and an electronic component using the same can be provided.

As mentioned above, the resin composition of the present invention is a resin composition comprising (A) a carboxyl-containing urethane resin and (E) a white coloring agent, and the cured coating has a Tg of less than 100°C and a loss tangent peak in the range of 0.5 to 1.5 in a dynamic viscoelasticity measurement at a frequency of 1 Hz, thereby achieving both high reflectivity and low warp after the reflow step.

The loss tangent (tanδ) is the ratio of the loss elastic modulus to the storage elastic modulus, indicating the degree of contribution to viscosity at that temperature. A loss tangent of 1 indicates that the viscosity and elasticity are in the same state. Furthermore, a loss tangent of 1 or more indicates an increase in viscosity, and a loss tangent of less than 1 indicates an increase in elasticity. The larger the peak of this loss tangent is, the more energy generated by force and strain is diffused to the outside. Therefore, the generated stress and strain are easily relaxed.

Generally speaking, the lower the crosslinking density of the resin, the softer the formed coating is, and the less warp after curing. By blending the components of the resin composition of the present invention in the blending amounts described in (1) to (3) below, the peak of the loss tangent (tanδ) is adjusted to between 0.5 and 1.5, and low warp can be achieved after the reflow step, which was difficult with the previous method. (1) 75 to 90 parts by weight of (A) a carboxyl group-containing urethane resin having a stress-relieving effect is blended with a total of 100 parts by weight of a carboxyl group-containing resin including (F) another carboxyl group-containing resin. (2) When the resin composition of the present invention is a photosensitive resin composition, 20 to 100 parts by weight of (B) a difunctional (meth)acrylate is blended with a total of 100 parts by weight of the (meth)acrylate in order to prevent the crosslinking density from being too high. (3) 50 to 500 parts by weight of (E) a white colorant is blended with a total of 100 parts by weight of the carboxyl group-containing urethane resin and the carboxyl group-containing resin including (F) another carboxyl group-containing resin. Here, the range of the peak of the loss tangent (tanδ) is preferably 0.6 to 1.1, and further preferably 0.8 to 1.0 in order to reduce the warp. Furthermore, when the peak of the loss tangent (tanδ) exceeds 1.5, it is shown that the material has very strong viscosity, and it is difficult for such a material to maintain characteristics such as welding heat resistance and plating resistance.

The Tg of the cured coating film of the resin composition of the present invention in dynamic viscoelasticity measurement at a frequency of 1 Hz is more preferably 30°C to 90°C, and further preferably 40°C to 70°C. The Tg can also be adjusted to the above range by blending each component of the resin composition of the present invention in the blending amounts described in (1) to (2) below. (1) In the total 100 parts by mass of the carboxyl group-containing urethane resin (A) that is effective in stress relaxation, based on the total 100 parts by mass of the carboxyl group-containing resin that also includes (F) other carboxyl group-containing resin, 75 to 90 parts by mass, more preferably 80 to 90 parts by mass, (2) when the resin composition of the present invention is a photosensitive resin composition, in order not to make the cross-linking density too high, relative to (meth)acrylic acid The total amount of the ester is 100 parts by mass, and 20 to 100 parts by mass of (B) difunctional (meth)acrylate with a small number of functional groups is blended.

The resin composition of the present invention is a resin composition containing (A) carboxyl group-containing urethane resin and (E) a white coloring agent. Specifically, (A) carboxyl group-containing urethane resin The resin is preferably one containing a carboxyl-containing urethane resin without an aromatic ring, (B) a difunctional (meth)acrylate, (C) a photopolymerization initiator, and (D) an epoxy resin. at least several of them. Each of these components will be described in detail below. When the resin composition of the present invention is a thermosetting resin composition, it is preferred to contain (D) epoxy resin. When the resin composition of the present invention is a photosensitive resin composition, it is preferred to contain (B). ) difunctional (meth)acrylate, (C) photopolymerization initiator.

[(A) Carboxyl group-containing urethane resin] The resin composition of the present invention contains (A) carboxyl group-containing urethane resin which is effective in stress relaxation. Furthermore, (A) the carboxyl group-containing urethane resin of the present invention preferably contains (A-1) a carboxyl group-containing urethane resin which does not have an aromatic ring and (A-2) which has an aromatic ring. At least any one of carboxyl group-containing urethane resins derived from diols and aliphatic diisocyanates.

The resin composition of the present invention preferably contains (A-1) a carboxyl group-containing urethane resin that does not have an aromatic ring. By containing the carboxyl group-containing urethane resin (A-1) which does not have an aromatic ring, discoloration due to heat can be suppressed and a coating film with high reflectance can be obtained. (A-1) A carboxyl group-containing urethane resin that does not have an aromatic ring, preferably polyisocyanate (a), which is an aliphatic diisocyanate that is a non-aromatic compound having an isocyanate group, and 1 Carboxyl group-containing urethane resin obtained by reacting a compound with two or more alcoholic hydroxyl groups in a molecule and a compound with one alcoholic hydroxyl group in a molecule. (A-1) A carboxyl group-containing urethane resin that does not have an aromatic ring, except that its material does not contain the diol (b) that has an aromatic ring and contains a repeating unit derived from an alicyclic diol as a structural unit. Polycarbonate diol (c-2), polycarbonate diol (c-3) containing repeating units derived from diols derived from both linear aliphatic diol and alicyclic diol as structural units The rest can be synthesized in the same manner as (A-2) the carboxyl group-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate. As the polyisocyanate (a) of the aliphatic diisocyanate, various commonly known polyisocyanates can be used, and the polyisocyanate is not limited to a specific compound. Specific examples of the aliphatic diisocyanate polyisocyanate (a) include diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. These polyisocyanates can be used alone or in combination of two or more types. Among these, trimethylhexamethylene diisocyanate is preferred. When such a diisocyanate is used, a cured product excellent in welding heat resistance can be obtained. In addition, the polyisocyanate is not limited to the polyisocyanate (a) of aliphatic diisocyanate as long as it does not have an aromatic ring. For example, isophorone diisocyanate, cyclohexane-1,3-dimethylene diisocyanate can also be used. Isocyanate, polyisocyanate of cyclohexane-1,4-dimethylene diisocyanate. As the compound having two or more alcoholic hydroxyl groups in one molecule, polycarbonate diol or a compound having a carboxyl group and two or more alcoholic hydroxyl groups is preferred. The polycarbonate diol is preferably a polycarbonate diol (c-1) containing one or more repeating units derived from a linear aliphatic diol as a structural unit. Specific examples are the same as described below. . As a compound having a carboxyl group and two or more alcoholic hydroxyl groups, dimethylol alkanoic acid (d) is preferred, and specific examples are the same as described below. As a compound having one alcoholic hydroxyl group per molecule, a monohydroxy compound (e) described below is preferred, and specific examples are the same as those described below. As (A-1) the carboxyl group-containing urethane resin having no aromatic ring, a polyisocyanate having no aromatic ring and a repeating polyisocyanate derived from a linear aliphatic diol containing one or more types are used. In the case of a carboxyl group-containing urethane resin obtained by reacting polycarbonate diol (c-1), dimethylol alkanoic acid (d) and a monohydroxy compound (e) as structural units, it can be It is preferable because it has the effect of suppressing discoloration due to heat and obtaining a coating film with higher reflectivity.

The resin composition of the present invention is preferably a carboxyl group-containing urethane resin derived from (A-2) a diol having an aromatic ring and an aliphatic diisocyanate. Low warpage can be achieved by containing (A-2) a carboxyl group-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate and a bifunctional (meth)acrylate. (A-2) The carboxyl group-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate is preferably a polyisocyanate (a) having an aliphatic diisocyanate and a diol having an aromatic ring ( b) The urethane bond formed by the reaction, further having the urethane bond formed by the reaction of the polycarbonate polyol (c) and the dimethylol alkanoic acid (d), and having the above The carboxyl group introduced by dihydroxymethylalkanoic acid (d). During the reaction, a monohydroxy compound (e) may also be added as a reaction terminating agent (terminal blocking agent).

(A-2) Carboxyl-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate, for example, polyisocyanate (a) of an aliphatic diisocyanate, diol (b) having an aromatic ring, polycarbonate polyol (c), dihydroxymethyl alkanoic acid (d) and a monohydroxy compound (e) are all mixed and reacted, or polyisocyanate (a) of an aliphatic diisocyanate, diol (b) having an aromatic ring, polycarbonate polyol (c) and dihydroxymethyl alkanoic acid (d) are reacted and then reacted with a monohydroxy compound (e) which functions as a reaction terminator. Furthermore, for example, it is also preferable to mix all of the polycarbonate polyol (c), the diol (b) having an aromatic ring, the dihydroxymethyl alkanoic acid (d) and the monohydroxy compound (e) functioning as a reaction terminator, and react them with the polyisocyanate (a) of the aliphatic diisocyanate. The reaction is carried out without a catalyst by stirring and mixing at room temperature to 100°C, and preferably heated to 70 to 100°C to increase the reaction rate. Furthermore, the reaction ratio (molar ratio) of the above-mentioned (a) to (d) components is (b): (c) = 1:9 to 9:1, preferably 2:8 to 8:2; (b+c): (d) = 95:5 to 5:95, preferably 80:20 to 15:85; (a): (b+c+d) = 1:1 to 2:1, preferably 1:1 to 1.5:1; (a+b+c+d): (e) = 1:0.01 to 0.5, preferably 1:0.02 to 0.3.

As the polyisocyanate (a) of the aliphatic diisocyanate, various commonly known polyisocyanates can be used, and the polyisocyanate is not limited to a specific compound. Specific examples are the same as above.

As the diol (b) having an aromatic ring, a bisphenol A-type alkylene oxide adduct diol is preferred. Specific examples include bisphenol A's ethylene oxide adduct, propylene oxide adduct, and butylene oxide adduct. Among these, the propylene oxide adduct of bisphenol A is from It is good from the viewpoint of improving welding heat resistance.

As the polycarbonate polyol (c), polycarbonate diol (polycarbonate diol) is preferred. Examples of the polycarbonate diol include polycarbonate diols (c-1) containing one or more repeating units derived from linear aliphatic diols as structural units, polycarbonate diols (c-1) containing one or two types The above polycarbonate diol (c-2) having a repeating unit derived from an alicyclic diol as a constituent unit or a polycarbonate diol (c) containing a repeating unit derived from both diols as a constituent unit -3).

Specific examples of the polycarbonate diol (c-1) containing repeating units derived from a linear aliphatic diol as constituent units include, for example, polycarbonate diol derived from 1,6-hexanediol, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol, polycarbonate diol derived from 1,4-butanediol and 1,6-hexanediol, and polycarbonate diol derived from 3-methyl-1,5-pentanediol and 1,6-hexanediol.

Specific examples of the polycarbonate diol (c-2) containing a repeating unit derived from an alicyclic diol as a structural unit include, for example, polycarbonate diol derived from 1,4-cyclohexanedimethanol. alcohol.

Specific examples of the polycarbonate diol (c-3) containing repeating units derived from both linear aliphatic diol and alicyclic diol as structural units include, for example, 1,6 -Polycarbonate diol derived from hexanediol and 1,4-cyclohexanedimethanol.

Polycarbonate diols containing repeating units derived from linear aliphatic diols as constituent units tend to have low warpage and excellent flexibility. Furthermore, polycarbonate diols containing repeating units derived from alicyclic diols as constituent units tend to have high crystallinity, excellent tinning resistance, and excellent soldering heat resistance. From the above viewpoints, these polycarbonate diols are used in combination of two or more, or polycarbonate diols containing repeating units derived from both linear aliphatic diols and alicyclic diols as constituent units can be used. In order to achieve a good balance among low warpage, flexibility, soldering heat resistance, and tinning resistance, it is preferred to use polycarbonate diol having a copolymerization ratio of linear aliphatic diol to alicyclic diol of 3:7 to 7:3 by mass.

The polycarbonate diol preferably has a number average molecular weight of 200 to 5,000. The polycarbonate diol contains repeating units derived from a linear aliphatic diol and an alicyclic diol as structural units. The linear unit is When the copolymerization ratio of aliphatic diol and alicyclic diol is 3:7 to 7:3 by mass, the number average molecular weight is preferably 400 to 2,000.

Dimethylol alkanoic acid (d) is a dihydroxy aliphatic carboxylic acid having a carboxyl group, and specific examples thereof include dimethylol propionic acid, dimethylol butyric acid, and the like. By using dimethylol alkanoic acid (d), a carboxyl group can be easily introduced into the urethane resin.

As the monohydroxy compound (e), any compound having one hydroxyl group in the molecule that serves as the end-capping agent for polyurethane can be listed, and examples thereof include aliphatic alcohol (e-1) and mono(meth)acrylate monohydroxy ester compound (e-2). As specific examples of aliphatic alcohol (e-1), methanol, ethanol, propanol, isobutanol, etc. can be listed, and as specific examples of mono(meth)acrylate monohydroxy ester compound (e-2), 2-hydroxyethyl acrylate, etc. can be listed.

When the carboxyl group-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate as described above (A-2) is a carboxyl group-containing urethane resin obtained by reacting (A) (a) polyisocyanate, (b) bisphenol A-based alkylene oxide adduct diol, (c) polycarbonate diol and (d) dihydroxymethyl alkanoic acid, it is preferable to use a difunctional (meth)acrylate in combination to achieve a low warp effect that further suppresses warp.

(A) The weight average molecular weight of the carboxyl group-containing urethane resin is preferably 500 to 100,000, more preferably 8,000 to 50,000. Here, the weight average molecular weight is a polystyrene-converted value measured by gel permeation chromatography. (A) If the weight average molecular weight of the carboxyl group-containing urethane resin is less than 500, the extensibility, flexibility, and strength of the cured film may be impaired. On the other hand, if it exceeds 100,000, the weight average molecular weight may become hard and may Reduce the risk of flexibility.

(A) The acid value of the carboxyl group-containing urethane resin is preferably in the range of 5 to 150 mgKOH/g, and more preferably 10 to 100 mgKOH/g. If the acid value is less than 5 mgKOH/g, the reactivity with the thermosetting component is reduced, which may impair the heat resistance. On the other hand, if the acid value exceeds 150 mgKOH/g, the alkali resistance and electrical properties of the cured film as a photoresist may be reduced. The acid value of the resin is a value measured in accordance with JIS K5407.

The blending amount of (A-1) a carboxyl-containing urethane resin without an aromatic ring is 50 to 95 parts by mass, preferably 60 to 70 parts by mass, relative to 100 parts by mass of the total amount of (A) a carboxyl-containing resin and (F) other carboxyl-containing resins. The blending amount of (A-2) a carboxyl-containing urethane resin derived from a diol having an aromatic ring and an aliphatic diisocyanate is 5 to 90 parts by mass, preferably 10 to 20 parts by mass, relative to 100 parts by mass of the total amount of (A) a carboxyl-containing resin and (F) other carboxyl-containing resins.

[(B) Difunctional (meth)acrylate] The resin composition of the present invention contains difunctional (meth)acrylate. Since (meth)acrylate has an ethylenically unsaturated group, it is photocured by irradiation with active energy rays, which helps the resin composition of the present invention to be insoluble in alkaline aqueous solutions. (Meth)acrylate The (B) difunctional (meth)acrylate of the present invention is difunctional, so it forms a cross-linked structure, and especially when used in combination with the (A) component, it can satisfy the so-called opposite physical properties of the hardened coating film, namely, the softness and hardness. In addition, since the number of functional groups per unit molecular weight is large, such as trifunctional or higher (meth)acrylates, the polymerization shrinkage becomes larger, and the amount of admixture must be set to a predetermined range. Specifically, when the (meth)acrylate contained in the photosensitive resin composition of the present invention is taken as 100 parts by mass, the blending amount of (B) difunctional (meth)acrylate is preferably 20 parts by mass to 100 parts by mass, and more preferably 40 parts by mass to 100 parts by mass. The blending amount of trifunctional or higher (meth)acrylate is 40 parts by mass to 80 parts by mass when the (meth)acrylate contained in the photosensitive resin composition of the present invention is taken as 100 parts by mass, and warp can be suppressed even if it is contained. The (meth)acrylate of tetrafunctional or higher is 5 parts by mass or less when the (meth)acrylate contained in the photosensitive resin composition of the present invention is taken as 100 parts by mass, and warp can be suppressed. In particular, in the case of hexafunctional or higher (meth)acrylates, the number of functional groups per unit molecular weight increases, the polymerization shrinkage rate increases, and the warp deteriorates. In the photosensitive resin composition of the present invention, when the (meth)acrylate contained in the photosensitive resin composition of the present invention is taken as 100 parts by mass, it is preferably less than 1 part by mass.

Specific examples of the (B) bifunctional (meth)acrylate include diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol. Class; polyols such as hexylene glycol, trimethylolpropane, neopentyl erythritol, dineopenterythritol, hydroxyethyl isocyanate or their ethylene oxide adducts, propylene oxide Adducts, or diacrylates such as ε-caprolactone adducts; phenoxyacrylates, bisphenol A diacrylates, and ethylene oxide adducts of these phenols or propylene oxide Diacrylates such as adducts; epoxy such as glycerol diglycidyl ether, glyceryl triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidoxypropyl isocyanate, etc. Diacrylates of propyl ether; not limited to the above, polyols such as polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, polyester polyol, etc. can be directly acrylated, or through diisocyanate Urethane acrylate diacrylates and melamine diacrylates, and/or dimethacrylates corresponding to the above-mentioned diacrylates, etc.

Furthermore, polyfunctional epoxy resins such as cresol novolac epoxy resins, epoxy diacrylate resins made by reacting diacrylate, and epoxy urethane diacrylate compounds made by reacting hydroxyl groups of the epoxy diacrylate resins with hydroxyl acrylates such as pentaerythritol triacrylate and diisocyanate compounds such as isophorone diisocyanate, etc. Such epoxy diacrylate resins can improve light curing properties without reducing the dryness upon touch.

(B) The blending amount of the difunctional (meth)acrylate is appropriately 5 to 5 parts by mass based on 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. 100 parts by mass, more preferably 5 to 70 parts by mass. When the blending amount is within the above range, the photocurability is good, a pattern can be formed by alkali development after irradiation with active energy rays, and the solubility in an alkaline aqueous solution is good.

[(C) Photopolymerization initiator] The resin composition of the present invention can use a well-known and commonly used (C) photopolymerization initiator. (C) The photopolymerization initiator can be used alone, or two or more types can be used in combination, and one preferably has a photobleaching effect. The photofading effect means that when the photopolymerization initiator absorbs light and generates free radicals, the conjugated bonds of the cracked molecules are cut, and the absorbance in the ultraviolet region is reduced, so that it does not prevent ultraviolet rays from penetrating inside. Preferable examples of the (C) photopolymerization initiator having a photofading effect include a monocarboxylic acid phosphine oxide-based photopolymerization initiator and a bis-carboxylic acid phosphine oxide-based photopolymerization initiator. Examples of the monocarboxylic acid phosphine oxide-based photopolymerization initiator include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2,6-dimethoxybenzoyldiphenylphosphine oxide. Phosphine, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine methyl ester, 2-methylbenzoyldiphenyl Phosphine oxide, trimethylacetyl (pivaloyl) phenyl isopropyl phosphinate, etc. Among them, 2,4,6-trimethylbenzyldiphenylphosphine oxide is easily available.

Examples of the bisacylphosphine oxide-based photopolymerization initiator include bis-(2,6-dichlorobenzyl)phenylphosphine oxide, bis-(2,6-dichlorobenzyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxyphenyl)- bis-(2,4,6-trimethylbenzyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzyl)phenylphosphine oxide, (2,5,6-trimethylbenzyl)-2,4,4-trimethylpentylphosphine oxide, etc. Among them, bis-(2,4,6-trimethylbenzyl)phenylphosphine oxide (manufactured by BASF Japan Co., Ltd., trade name: Irgacure 819) is easily available.

Furthermore, the total blending amount of the photopolymerization initiator is preferably 1 to 30 parts by mass relative to 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. Parts by mass, preferably 2 to 25 parts by mass. If the blending amount is within the above range, the photocurability of the coating film will be good, and the pattern formation after exposure and development will also be good.

[(D) Epoxy resin] In order to improve the heat resistance of the cured product, the curable resin composition of the present invention can use a well-known and commonly used (D) epoxy resin. The (D) epoxy resin can be used alone or as a mixture of two or more. Specific examples of epoxy resins include bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, brominated bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, novolac type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, N-epoxypropyl type epoxy resins, bisphenol A novolac type epoxy resins, Epoxy resins, diisocyanate-type epoxy resins, biphenol-type epoxy resins, chelate-type epoxy resins, glyoxal-type epoxy resins, amino-containing epoxy resins, rubber-modified epoxy resins, diisocyanate-type epoxy resins, diisocyanate-phthalate resins, heterocyclic epoxy resins, tetraisocyanate-butyl phthalate resins, polysilicone-modified epoxy resins, ε-caprolactone-modified epoxy resins, etc. Furthermore, in order to impart flame retardancy, materials having halogens such as chlorine and bromine, and atoms such as phosphorus introduced into their structures may also be used.

The blending amount of (D) epoxy resin in the resin composition of the present invention is preferably 5 parts by mass based on 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. ~150 parts by mass, preferably 10 ~80 parts by mass. When the blending amount is within the above range, the cured coating film of the photosensitive resin composition has good soldering heat resistance, and when used as an insulating protective film for a printed circuit board, various properties, especially electrical insulation, are also good. .

[(E) White coloring agent] In the resin composition of the present invention, (E) the white coloring agent is used to whiten the cured coating film, and examples thereof include titanium oxide, zinc oxide, potassium titanate, zirconium oxide, antimony oxide, lead white, and zinc sulfide. , lead titanate, barium titanate, etc. As the white coloring agent (E) of the present invention, titanium oxide is preferred because of its high effect of suppressing discoloration due to heat. As the titanium oxide, those produced by the sulfuric acid method, the chlorination method, rutile titanium oxide, anatase titanium oxide, or those surface-treated with a hydrous metal oxide or surface-treated with an organic compound can be used. Titanium oxide. Among these titanium oxides, rutile titanium oxide is preferred. Anatase titanium oxide is often used because it has a higher whiteness than rutile titanium oxide. However, due to its photocatalytic activity, it may cause discoloration of the resin in the curable resin composition. In contrast, rutile titanium oxide is slightly inferior to anatase titanium oxide in terms of whiteness, but it has almost no photoactivity and can obtain a stable hardened coating film. As the rutile titanium oxide, a well-known rutile titanium oxide can be used. Specifically, TR-600, TR-700, TR-750, and TR-840 manufactured by Fuji Titanium Industry Co., Ltd., and R-550, R-580, R-630, and R-820 manufactured by Ishihara Industrial Co., Ltd. can be used. , CR-50, CR-60, CR-90, KR-270, KR-310, KR-380 made by Titan Kogyo Co., Ltd., etc. Among these rutile titanium oxides, titanium oxide whose surface is treated with hydrous aluminum oxide or aluminum hydroxide is particularly preferred from the viewpoint of dispersibility in the composition and storage stability.

The blending amount of the white colorant (E) is preferably in the range of 50 to 500 parts by mass, preferably 100 to 450 parts by mass, and more preferably 150 to 450 parts by mass, relative to 100 parts by mass of the total amount of the (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. If the blending amount of the white colorant (E) is less than 50 parts by mass, it is difficult to form a good white cured coating film. If the blending amount of the white colorant (E) is within the above range, a good white cured coating film can be formed, the viscosity of the composition is not too high, the coating and moldability are good, and the cured product does not become brittle.

[(F) Other carboxyl group-containing resins ((A) Carboxyl group-containing resins other than carboxyl group-containing urethane resin)] The resin composition of the present invention preferably contains a carboxyl group-containing resin other than (A) carboxyl group-containing urethane resin as (F) other carboxyl group-containing resin. The blending amount of (F) other carboxyl group-containing resin in the resin composition of the present invention is based on 100 parts by mass of the total of (F) other carboxyl group-containing resin and (A) carboxyl group-containing urethane resin. , preferably 5 to 50 parts by mass, and further preferably 10 to 20 parts by mass. (F) If the blending amount of other carboxyl group-containing resin is within the above range, the peaks of Tg and loss tangent (tanδ) can be easily adjusted. As (F) other carboxyl group-containing resins, well-known and commonly used carboxyl group-containing resins can be used, and by using them in combination with (A) carboxyl group-containing urethane resins, it is possible to obtain high reflection that further suppresses discoloration due to heat. The carboxyl group-containing resin listed below is preferred for a high-efficiency coating film. (1) A copolymer having a carboxyl group obtained by reacting (a) a carboxyl group-containing (meth)acrylic copolymer resin and (b) a compound having an oxirane ring and an ethylenically unsaturated group in one molecule Polymer resin. (2) Obtained by copolymerization of unsaturated carboxylic acids such as (meth)acrylic acid and unsaturated group-containing compounds selected from styrene, α-methylstyrene, lower alkyl (meth)acrylate, isobutylene, etc. A carboxyl-containing resin with a styrene skeleton (either an oligomer or a polymer). In addition, the lower alkyl group refers to an alkyl group having 1 to 5 carbon atoms.

[Other thermosetting components] The resin composition of the present invention can be blended with a thermosetting component in order to further improve heat resistance. As the thermosetting component, amine resins such as melamine resins and benzoguanamine resins, blocked isocyanate compounds, cyclocarbonate compounds, polyfunctional oxetane compounds, episulfide resins, melamine derivatives, dimaleimide, oxazine compounds, oxazoline compounds and other well-known and commonly used thermosetting resins can be used. Preferably, the thermosetting component has a plurality of cyclic (thio)ether groups in the molecule that can react with the carboxyl-containing resin (or further phenolic hydroxyl group) starting with the carboxyl-containing urethane resin (A).

In the resin composition of the present invention, the thermosetting component may be used alone or in combination of two or more. The blending amount is preferably 5 to 150 parts by mass, preferably 10 to 80 parts by mass, based on 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. The ratio. If the blending amount is within the above range, the cured coating film of the resin composition will have good soldering heat resistance, and will also have good various properties when used as an insulating protective film, especially electrical insulation properties.

(Other components) In order to promote the heat curing reaction and further improve the properties such as adhesion, chemical resistance, and heat resistance, a heat curing catalyst can be formulated in the resin composition of the present invention. Examples of such heat-curing catalysts include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Furthermore, as commercial products, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (all are trade names of imidazole compounds) manufactured by Shikoku Chemical Industries, Ltd., U-CAT (registered trademark) 3503N, U-CAT3502T (all are trade names of dimethylamine blocked isocyanate compounds), DBU, DBN, U-CATSA102, U-CAT5002 (all are bicyclic amidine compounds and their salts) manufactured by SAN-APRO Co., Ltd. are listed. In particular, it is not limited to these, as long as it is a heat-curing catalyst for epoxy resins and oxetane compounds, or a substance that promotes the reaction between epoxy groups and/or oxetane groups and carboxyl groups, and it can be used alone or in combination of two or more. Furthermore, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine・isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine・isocyanuric acid adduct can also be used. It is preferred to use these compounds that also act as adhesion imparting agents together with the heat-curing catalyst.

These thermosetting catalysts can be used alone or in mixture of two or more types, and the blending amount is sufficient in a normal amount ratio, for example, relative to (A) carboxyl group-containing urethane resin and (F) other The total amount of carboxyl-containing resin, or the total amount of (D) epoxy resin and other thermosetting components per 100 parts by mass, is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15.0 parts by mass.

In the resin composition of the present invention, an organic solvent can be used in order to easily dissolve or disperse (A) to (F) and other components as needed, or to adjust the viscosity to a suitable viscosity for coating. Examples of the organic solvent include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, and carbitol acetate. , Propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, methyl methoxy propionate, ethyl methoxy propionate, ethoxy methyl propionate, Ethoxyethyl propionate, ethyl acetate, n-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone, N,N-dimethylformamide, N , N-dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, dimethylserioxide, chloroform and methylene chloride, etc. The blending amount of the organic solvent can be appropriately set according to the desired viscosity.

The resin composition of the present invention may contain well-known and commonly used mercapto compounds and adhesion accelerators in order to improve the adhesion with base materials such as polyimide according to needs. Examples of mercapto compounds include 2-mercaptopropionic acid, trimethylolpropane (2-thiopropionate), 2-mercaptoethanol, 2-aminothiophenol, and 3-mercapto-1,2,4- Thiol-containing silane coupling agents such as triazole and 3-mercapto-propyltrimethoxysilane. Examples of adhesion accelerators include benzimidazole, benzoxazole, benzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoethazole, 2-mercaptobenzothiazole, and 3-morpholine Methyl-1-phenyl-triazole-2-thione, 5-amino-3-morpholinylmethyl-thiazole-2-thione, 2-mercapto-5-methylthio-thione Azole, triazole, tetrazole, benzotriazole, carboxybenzotriazole, amino-containing benzotriazole, vinyl triazine, etc. These can be used individually or in combination of 2 or more types. The blending amount is appropriately within the range of 10 parts by mass or less per 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins. When the blending amount of these compounds is within the above range, the consumption of the epoxy groups in the reaction with the epoxy groups of the (D) epoxy resin required for the cross-linking reaction is within an appropriate range, and the cross-linking density is also good. , so it is better.

Since most polymer materials begin to oxidize, chain oxidative deterioration occurs one after another, resulting in a decrease in the function of the polymer material. In order to prevent oxidation, the curable resin composition of the present invention can add (1) to reduce the generated free radicals. Inactive free radical scavengers or/and (2) antioxidants such as peroxide decomposers that decompose generated peroxides into harmless substances so that new free radicals are not generated.

As antioxidants that function as free radical scavengers, for example, 4-t-butylcatechol, 2-t-butylhydroquinone, hydroquinone monomethyl ether, 2,6-di-t-butyl-p-cresol, 2,2-methylene-bis(4-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 2,6-di-t-butyl-p-cresol, 2,2-methylene-bis(4-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 2,6-di-t-butyl-p-cresol ... Phenol compounds such as (3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3',5'-di-t-butyl-4-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, quinone compounds such as menadione (metaquinone) and benzoquinone, and amine compounds such as bis(2,2,6,6-tetramethyl-4-piperidinyl)-sebacic acid ester.

The free radical scavenger may be a commercially available product, for example, ADK STAB (registered trademark) AO-30, ADK STAB AO-330, ADK STAB AO-20, ADK STAB LA-77, ADK STAB LA-57, ADK STAB LA-67, ADK STAB LA-68, ADK STAB LA-87 (all manufactured by ADEKA Co., Ltd.), Irganox (registered trademark) 1010, Irganox 1035, Irganox 1076, Irganox 1135, Tinuvin (registered trademark) 111FDL, Tinuvin 123, Tinuvin 144, Tinuvin 152, Tinuvin 292, Tinuvin 5100 (all manufactured by BASF Japan Co., Ltd.), etc.

As antioxidants that function as peroxide decomposers, for example, phosphorus compounds such as triphenyl phosphite, sulfur compounds such as pentaerythritol tetralaurylthiopropionate, dilaurylthiodipropionate, and distearyl 3,3'-thiodipropionate, etc. can be cited. Peroxide decomposers can be commercially available products, and for example, ADK STAB TPP (manufactured by ADEKA Co., Ltd.), ADK STAB AO-412S (manufactured by ADEKA Co., Ltd.), SUMILIZER (registered trademark) TPS (manufactured by Sumitomo Chemical Co., Ltd.), etc. can be cited. The antioxidants can be used alone or in combination of two or more.

The resin composition of the present invention can use an ultraviolet absorber in addition to an antioxidant. Examples of such ultraviolet absorbers include benzoketone derivatives, benzoate derivatives, benzotriazole derivatives, triazine derivatives, benzothiazole derivatives, cinnamic acid derivatives, and o-aminobenzoyl derivatives. Acid ester derivatives, benzylmethane derivatives, etc.

Examples of the phenyl ketone derivative include 2-hydroxy-4-methoxyphenyl ketone, 2-hydroxy-4-methoxyphenyl ketone, 2-hydroxy-4-n-octoxyphenyl ketone, 2,2'-dihydroxy-4-methoxyphenyl ketone, and 2,4-dihydroxyphenyl ketone.

Examples of benzoate derivatives include 2-ethylhexyl salicylate, phenyl salicylate, p-t-butyl phenyl salicylate, and 2,4-di-t-butylphenyl-3, 5-di-t-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, etc.

Examples of the benzotriazole derivatives include 2-(2'-hydroxy-5'-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, and 2-(2'-hydroxy-3',5'-di-t-pentylphenyl)benzotriazole.

Examples of triazine derivatives include hydroxyphenyltriazine, bisethylhexyloxyphenolmethoxyphenyltriazine, and the like.

The ultraviolet absorber may be a commercially available one, and examples thereof include Tinuvin PS, Tinuvin 99-2, Tinuvin 109, Tinuvin 384-2, Tinuvin 900, Tinuvin 928, Tinuvin 1130, Tinuvin 400, Tinuvin 405, Tinuvin 460, Tinuvin 479 (all owned by BASF Japan), etc.

The resin composition of the present invention may further contain at least one filler selected from the group consisting of inorganic fillers and organic fillers for the purpose of improving characteristics such as adhesion, hardness, and heat resistance according to requirements. Examples of inorganic fillers include barium sulfate, calcium carbonate, silicon oxide, amorphous silica, talc, clay, hydrotalcite, mica powder, etc. Examples of organic fillers include silicon powder, resistant Nylon powder, fluorine powder, etc. Among the above-mentioned fillers, silica is particularly excellent in low hygroscopicity and low volume expansion. Regardless of whether the silicon dioxide is molten or crystalline, it may be a mixture thereof. In particular, when the silicon dioxide is surface-treated with a coupling agent or the like, it is preferable because the electrical insulation properties can be improved. Furthermore, when the resin composition of the present invention is a thermosetting resin composition, it is necessary to adjust thixotropy for pattern printing, and it is preferable to contain silica. The average particle diameter of the filler is desirably 25 μm or less, more preferably 10 μm or less, further preferably 3 μm or less. The blending amount of these inorganic and/or organic fillers is, for every 100 parts by mass of the total amount of (A) carboxyl group-containing urethane resin and (F) other carboxyl group-containing resins, 300 parts by mass or less is appropriate. The preferred ratio is 5 to 150 parts by mass. If the blending amount of the filler exceeds the above ratio, the flexibility of the cured coating film decreases, which is undesirable.

Furthermore, other additives other than the above-mentioned components may be added to the resin composition of the present invention as long as the effects of the present invention are not impaired. Examples of additives include well-known and commonly used tackifiers such as organobentonite and montmorillonite, defoaming agents and/or leveling agents such as polysiloxane-based, fluorine-based, and polymer-based defoaming agents, glass fiber, carbon fiber, and boron nitride. Fiber and other fiber reinforced materials, etc. Furthermore, well-known and commonly used thermal polymerization inhibitors, silane coupling agents such as imidazole series, thiazole series, and triazole series, dispersants, defoaming agents, plasticizers, foaming agents, flame retardants, antistatic agents, etc. can be added as needed. Anti-aging agents, antibacterial and antifungal agents, etc.

(Preparation and use of resin composition) The resin composition having the above composition can be obtained by dissolving or dispersing the above components or the following components as required using a mixer such as a disperser, a kneader, a three-drum mill, a bead mill, etc. At this time, a solvent inert to epoxy groups and phenolic hydroxyl groups can also be used. As such an inert solvent, the above organic solvent is preferred.

The resin composition of the present invention can be applied to a printed circuit board by various conventionally known methods such as curtain coating, roller coating, spray coating, and dip coating. It can be used in a variety of forms and applications, such as dry film or prepreg. Various solvents can be used depending on the usage method and purpose. Depending on the situation, not only good solvents but also poor solvents can be used.

Furthermore, the resin composition of the present invention can be applied to a glass substrate by screen printing to form a flexible printed circuit board with a circuit, and then heated to a temperature of, for example, 120 to 180° C. to be thermally cured, thereby forming a white cured coating film that has no warping due to curing shrinkage and cooling shrinkage, and has good adhesion to the substrate, folding resistance, low warping, electroless gold plating resistance, soldering heat resistance, electrical insulation, etc., and has a good balance between flexibility and high reflectivity, and has little reflectivity reduction over time.

The resin composition of the present invention is coated on a substrate by a dip coating method, a shower coating method, a roller coating method, a rod coating method, a screen printing method, a curtain coating method, etc., and the organic solvent contained in the composition is evaporated and dried (dried) at a temperature of about 60 to 100° C., thereby forming a non-sticky (take-free) coating film. When the resin composition is a photosensitive resin composition, after drying, it is selectively exposed to active energy rays through a photomask that forms a pattern, or directly exposed to the pattern through a laser direct writing exposure machine, and the unexposed part is developed with a dilute alkaline aqueous solution to form a photoresist pattern. Furthermore, when the resin composition is a photosensitive thermosetting composition that also contains a thermosetting component, it is heated at a temperature of, for example, about 140 to 180°C for 5 to 120 minutes to be thermoset (post-cured). Through this thermosetting, the carboxyl group (or further phenolic hydroxyl group) of the carboxyl-containing urethane resin (A) reacts with the thermosetting component (D) epoxy resin (or cyclic (thio) ether group of further other thermosetting components when included) to form a white cured coating that has a good balance between flexibility and high reflectivity and a small decrease in reflectivity over time, in addition to the characteristics of adhesion to the substrate, folding resistance, low warping, electroless gold plating resistance, soldering heat resistance, and electrical insulation. When the resin composition is a thermosetting resin composition that is not photosensitivity, it can be heated at a temperature of, for example, about 140 to 180°C for 5 to 120 minutes after drying to thermally cure (post-cure) the composition, thereby forming a white cured coating that achieves the same effect as the aforementioned photosensitive resin composition.

As the above-mentioned base material, in addition to glass substrates, printed circuit boards with pre-formed circuits, flexible printed circuit boards, paper-phenol resin, paper-epoxy resin, glass cloth-epoxy resin, glass-polyimide, glass cloth/non-woven fabric-epoxy resin, glass cloth/paper-epoxy resin, synthetic fiber-epoxy resin, copper laminates of all grades (FR-4, etc.) using composite materials such as fluorine resin, polyethylene, PPO, and cyanate, polyimide films, PET films, ceramic substrates, wafer boards, etc. can be used.

After the resin composition of the present invention is applied, volatile drying or heat curing (post-curing) can be performed using a hot air circulation dryer, an IR furnace, a heating plate, a convection oven, etc. (using a heat source with a method of heating air via steam, a method of making the hot air in the dryer contact in countercurrent, and a method of spraying air onto the support via a nozzle).

As the exposure machine used for the above-mentioned active energy ray irradiation, a direct writing device (such as a laser direct writing imaging device that directly draws an image with a laser through CAD data of a computer), an exposure machine equipped with a metal halide lamp, or an exposure machine equipped with ( Exposure machines equipped with ultra-) high-pressure mercury lamps, exposure machines equipped with short-arc mercury lamps, or direct writing devices using ultraviolet lamps such as (ultra-) high-pressure mercury lamps. As the active energy ray, any laser light with a maximum wavelength of 350 to 450 nm can be used, either a gas laser or a solid laser. In addition, the exposure amount varies depending on the film thickness, etc., but is generally in the range of 5 to 800 mJ/cm ² , and preferably in the range of 5 to 500 mJ/cm ² . As the direct writing device, for example, a product manufactured by Japan Orbotech Co., Ltd. can be used, and any device can be used as long as it is capable of oscillating laser light with a maximum wavelength of 350 to 450 nm.

The developing method may be an immersion method, a shower method, a spray method, a brush method, or the like, and the developer may be an alkaline aqueous solution of potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, or the like.

In addition to the method of directly applying the resin composition to a base material in a liquid form, the resin composition of the present invention can be coated with a film (first film) made of polyethylene terephthalate or the like in advance. It is used in the form of a dry film of the resin layer formed by drying. When the resin composition of the present invention is used as a dry film, it is as follows.

The dry film has a structure in which a first film, a resin layer, and a peelable second film are laminated in order. This resin layer is, for example, a layer obtained by applying a resin composition to a carrier film or a cover film and drying it. After the resin layer is formed on the first film, the second film is laminated thereon, or the resin layer is formed on the second film and the first film is laminated in bulk to obtain a dry film.

As the first film, a thermoplastic film such as a polyester film with a thickness of 2 to 150 μm can be used. The resin layer is formed by uniformly applying the resin composition to the first film or the second film with a thickness of 10 to 150 μm using a doctor blade coater, a lip coater (LIP Coater), a comma coater (Comma Coater), a film coater, etc., and drying. As the second film, a polyethylene film, a polypropylene film, etc. can be used, and it is better that the adhesion between the film and the resin layer is smaller than that of the first film.

To make a protective film (permanent protective film) on a substrate using a dry film, the second film is peeled off, the resin layer and the substrate with a circuit formed thereon are overlapped, and a lamination machine is used to bond them together to form a resin layer on the substrate with a circuit formed thereon. The formed resin layer can be exposed, developed, and heat-cured in the same manner as described above to form a hardened coating. The first film can be peeled off at any time point before exposure, after exposure, or before heat-curing. Example

Examples and comparative examples are shown below to illustrate the present invention in detail. However, the present invention is not limited to the following examples.

(Synthesis of Paint A-1-1) In a reaction vessel equipped with a stirring device, a thermometer, and a condenser, polycarbonate diol derived from 1,5-pentanediol and 1,6-hexanediol (Asahi Kasei (Co., Ltd.), TJ5650J, number average molecular weight 800) 2400g (3mol), dimethylol propionic acid 603g (4.5mol), and 238g (2.6mol) of 2-hydroxyethyl acrylate as a monohydroxy compound. Next, 1887g (8.5 mol) of isophorone diisocyanate, which is a polyisocyanate, was placed and heated to 60°C while stirring and stopped. When the temperature in the reaction vessel began to decrease, it was heated again at 80°C while stirring continuously. , the infrared absorption spectrum was used to confirm that the absorption spectrum of the isocyanate group (2280 cm ^-1 ) disappeared and the reaction was completed. Carbitol acetate was added so that the solid content became 50 mass %, and coating A-1-1 was obtained. The weight average molecular weight of the carboxyl-containing urethane resin is 17,000, and the acid value of the solid content is 50 mgKOH/g.

(Synthesis of Coating A-1-2) In a reaction container equipped with a stirrer, a thermometer, and a condenser, 2400 g (3.0 mol) of polycarbonate diol (T5650J, number average molecular weight 800, manufactured by Asahi Kasei Co., Ltd.) derived from 1,5-pentanediol and 1,6-hexanediol as a compound having two or more alcoholic hydroxyl groups, 603 g (4.5 mol) of dihydroxymethylbutyric acid, and 238 g (2.6 mol) of 2-hydroxyethyl acrylate as a monohydroxy compound were placed. Next, 1512 g (6.5 mol) of hexamethylene diisocyanate, a non-aromatic compound having an isocyanate group, was placed, and the mixture was heated to 60°C while stirring and stopped. When the temperature in the reaction vessel began to drop, the mixture was heated to 80°C again and stirred continuously. The absorption spectrum of the isocyanate group (2280 cm ^-1 ) disappeared by infrared absorption spectrum, and the reaction was terminated. Next, carbitol acetate was added to make the solid content 50% by mass, and a viscous liquid containing a carboxyl group, coating A-1-2, was obtained. The acid value of the solid content of the obtained carboxyl group-containing urethane resin was 49.8 mgKOH/g.

(Synthesis of coating material A-2-1) In a reaction container equipped with a stirrer, a thermometer and a condenser, 288 g (0.36 mol) of polycarbonate diol (number average molecular weight 800) derived from 1,5-pentanediol and 1,6-hexanediol as a polyol component, 45 g (0.09 mol) of bisphenol A type propylene oxide adduct diol (BPX33 manufactured by ADEKA Co., Ltd., number average molecular weight 500), 81.4 g (0.55 mol) of dihydroxymethylbutyric acid as dihydroxymethylalkanoic acid, 11.8 g (0.16 mol) of n-butanol as a molecular weight regulator (reaction terminator), and 250 g of carbitol acetate (manufactured by DAICEL Co., Ltd.) as a solvent were placed, and all the raw materials were dissolved at 60°C. While stirring the polyol component, 200.9 g (1.08 mol) of trimethyl hexamethylene diisocyanate as a polyisocyanate was dripped through a dropping funnel. After the dripping was completed, the reaction was continued while stirring at 80°C, and the absorption spectrum of the isocyanate group (2280 cm ^-1 ) disappeared by infrared absorption spectroscopy, and the reaction was terminated. Carbitol acetate was added to make the solid content 50% by mass, and a carboxyl-containing urethane resin coating A-2-1 containing a viscous liquid containing a diluent was obtained. The weight average molecular weight of the obtained carboxyl-containing urethane resin was 18,300, and the acid value of the solid content was 50.3 mgKOH/g. The average molecular weight was determined as a value converted to polystyrene using gel-supported liquid chromatography (HLC-8120 GPC, manufactured by Tosoh Corporation).

(Synthesis of coating material A-2-2) In a reaction container equipped with a stirrer, a thermometer and a condenser, 180 g (0.225 mol) of polycarbonate diol (number average molecular weight 800) derived from 1,5-pentanediol and 1,6-hexanediol as a polyol component, 112.5 g (0.225 mol) of bisphenol A type propylene oxide adduct diol (BPX33 manufactured by ADEKA Co., Ltd., number average molecular weight 500), 81.4 g (0.55 mol) of dihydroxymethylbutyric acid as dihydroxymethylalkanoic acid, 11.8 g (0.16 mol) of n-butanol as a molecular weight regulator (reaction terminator), and 250 g of carbitol acetate (manufactured by DAICEL Co., Ltd.) as a solvent were placed, and all the raw materials were dissolved at 60°C. While stirring the polyol component, 200.9 g (1.08 mol) of trimethyl hexamethylene diisocyanate as a polyisocyanate was dripped through a dropping funnel. After the dripping was completed, the reaction was continued while stirring at 80°C, and the absorption spectrum of the isocyanate group (2280 cm ^-1 ) disappeared by infrared absorption spectroscopy, and the reaction was terminated. Carbitol acetate was added to make the solid content 50% by mass, and a carboxyl-containing urethane resin coating A-2-2 containing a viscous liquid containing a diluent was obtained. The weight average molecular weight of the obtained carboxyl-containing urethane resin was 18,000, and the acid value of the solid content was 50.0 mgKOH/g. The average molecular weight was determined as a value converted to polystyrene using gel-supported liquid chromatography (HLC-8120 GPC, manufactured by Tosoh Corporation).

(Synthesis of coating material F-1 (other carboxyl-containing resin)) In a flask equipped with a thermometer, a stirrer, a dropping funnel and a reflux condenser, 325.0 parts by mass of dipropylene glycol monomethyl ether as a solvent was heated to 110°C, and a mixture of 174.0 parts by mass of methacrylic acid, 174.0 parts by mass of ε-caprolactone-modified methacrylic acid (average molecular weight 314), 77.0 parts by mass of methyl methacrylate, 222.0 parts by mass of dipropylene glycol monomethyl ether, and 12.0 parts by mass of tertiary butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, Perbutyl-O) as a polymerization catalyst was added dropwise over 3 hours, and the mixture was further stirred at 110°C for 3 hours to deactivate the polymerization catalyst, thereby obtaining a resin solution. After cooling the resin solution, add 289.0 parts by mass of Cyclomer M100 (Daicel Co., Ltd.), 3.0 parts by mass of triphenylphosphine, and 1.3 parts by mass of hydroquinone monomethyl ether, raise the temperature to 100°C, and stir to carry out the ring-opening addition reaction of the epoxy group to obtain coating F-1 with a solid content of 45.5% and a solid acid value of 79.8 mgKOH/g.

(Synthesis of coating F-2 (other carboxyl-containing resins)) Place 377g of tripropylene glycol monomethyl ether in a 2,000 ml flask equipped with a stirrer and cooling tube, and heat to 90°C under nitrogen flow. Mix and dissolve 104.2g of styrene, 246.5g of methacrylic acid, and 20.7 of dimethyl 2,2'-azobis(2-methylpropionate) (Fuji Films and Wako Pure Chemical Industries, Ltd.: V-601) g was dropped into the flask over 4 hours. By proceeding in this manner, carboxyl group-containing resin solution coating material F-2 was obtained. The solid content of this carboxyl-containing resin solution has an acid value of 120 mgKOH/g, a solid content of 50%, and a molecular weight of 20,000. Furthermore, the mass average molecular weight of the obtained carboxyl group-containing resin was determined by connecting a pump LC-6AD manufactured by Shimadzu Corporation and three Shodex (registered trademark) columns manufactured by Showa Denko Corporation, KF-804, KF-803, and KF- 802 high-speed liquid chromatography.

(Synthesis of coating F-3 (other carboxyl-containing resins)) 1070 g of o-cresol novolac epoxy resin (DIC Co., Ltd., EPICLON N-695, softening point 95°C, epoxy equivalent 214, average functional group number 7.6), 360 g of acrylic acid, and 1.5 g of hydroquinone were added to 600 g of diethylene glycol monoethyl ether acetate, and heated and stirred at 100°C to uniformly dissolve. Then, 4.3 g of triphenylphosphine was added, and the mixture was heated at 110°C for reaction for 2 hours, and then the temperature was raised to 120°C and the reaction was continued for another 12 hours. 415g of aromatic hydrocarbon (SOLVESSO 150) and 456.0g of tetrahydrophthalic anhydride were added to the obtained reaction solution, and the reaction was carried out at 110°C for 4 hours. After cooling, a coating F-3 with a solid acid value of 89mgKOH/g and a solid content of 65% was obtained.

(Preparation of resin composition) Using the obtained coatings (A-1-1), (A-1-2), (A-2-1), (A-2-2), (F-1), (F-2) and (F-3), the various components shown in Table 1 were blended in the indicated proportions (mass parts), pre-mixed in a blender, and then kneaded in a three-drum mill to prepare the resin compositions of Examples 1 to 11 and Comparative Examples 1 to 7. Unless otherwise specified, the values in the table are mass parts. In addition, the values in the table of each coating and other components are expressed in solid content.

(Measurement method of Tg and loss tangent (tanδ)) The peaks of Tg and loss tangent (tanδ) are formed by peeling off the cured coating film of the resin layer on the evaluation substrate for measuring the peaks of Tg and loss tangent (tanδ) described later from the copper foil, and passing the cured coating film through The dynamic viscoelasticity was measured in the tensile mode of a dynamic viscoelasticity measuring device (DMA, manufactured by TA Instruments Japan Co., Ltd., model: RSA-G2). The measurement conditions are as follows: the temperature range is -60°C to 300°C, the temperature rise rate is 5°C/min, the frequency is 1Hz, the strain is 0.1%, and the sample size is 5mm wide × 50mm long. The hardened coating film is provided so as to be fixed at both ends in the width direction, and the hardened coating film protruding from the chuck is cut off. The distance between the chucks is set to 10mm. In Table 1, the peaks of Tg and loss tangent (tan δ) in the dynamic viscoelasticity measurement at a frequency of 1 Hz of the cured coating films of each resin composition of Examples 1 to 11 and Comparative Examples 1 to 7 are listed together.

(Preparation of evaluation substrate for measurement of Tg and loss tangent (tanδ) peaks (hereinafter referred to as Tg, etc. measurement evaluation substrate)) The photosensitive resin composition of Examples 1 to 8 and Comparative Examples 1 to 6 was fully coated on a copper foil having a thickness of 18 μm by screen printing in such a manner that the film thickness after drying became 30 μm to form a resin layer. Thereafter, the resin layer was dried in a hot air circulation drying furnace at 80°C for 30 minutes, and then exposed at an exposure amount of 900 mJ/ ^cm2 using an exposure device equipped with a metal halogen lamp (HMW-680-GW20: ORC MANUFACTURING (Co., Ltd.)), and developed (30°C, 0.2 MPa, 1 mass% _{Na2CO3 aqueous} solution) for 60 seconds. Thereafter, the resin layer was cured in a hot air circulation drying oven at 150°C for 60 minutes to form a cured coating film of the resin layer, thereby preparing a substrate for measurement and evaluation of Tg and the like.

The thermosetting resin compositions of Examples 9 to 11 and Comparative Example 7 were fully coated on a copper foil with a thickness of 18 μm so that the film thickness after drying after screen printing became 30 μm to form a resin layer. Thereafter, the resin layer was cured in a hot-air circulation drying oven at 150° C. for 60 minutes to form a cured coating film of the resin layer, and a substrate for Tg and other measurement evaluations was produced.

(*1)(A)(A-1) Carboxyl-containing urethane resin without aromatic ring: Coating A-1-1 synthesized above (*2)(A)(A-1) Carboxyl-containing urethane resin without aromatic ring: Coating A-1-2 synthesized above (*3)(A)(A-2) Carboxyl-containing urethane resin derived from diol with aromatic ring and aliphatic diisocyanate: Coating A-2-1 synthesized above (*4)(A)(A-2) Carboxyl-containing urethane resin derived from diol with aromatic ring and aliphatic diisocyanate: Coating A-2-2 synthesized above (*5) Other carboxyl-containing resins described in (1) of the description of component (F): Coating F-1 synthesized above (*6) Other carboxyl-containing resins described in the description (2) of component (F): the above-synthesized coating F-2 (*7) (F) component: the above-synthesized coating F-3 (*8) (D) component: Mitsubishi Chemical Co., Ltd. bisphenol A type epoxy resin, trade name: jER828 (*9) (C) component: 2,4,6-trimethylbenzyldiphenylphosphine oxide, acylphosphine oxide-based photopolymerization initiator (*10) Thermosetting catalyst: Mitsubishi Chemical Co., Ltd. dicyandiamide, trade name: DICY7 (*11) Thermosetting catalyst: Nissan Chemical Co., Ltd. melamine, trade name: melamine (*12) (B) component: Nakamura Chemical Co., Ltd. bisphenol A type difunctional methacrylate, trade name: BPE-900 (*13) Trifunctional (meth)acrylate: Trihydroxymethylpropane EO modified triacrylate manufactured by Toa Gosei Co., Ltd. Trade name: M-350 (*14) Hexafunctional (meth)acrylate: Dipentatriol hexaacrylate manufactured by Nippon Kayaku Co., Ltd. Trade name: DPHA (*15) Dispersant: Wetting dispersant manufactured by BYK JAPAN Co., Ltd. Trade name: Disperbyk-111 (*16) (E) ingredient: Rutile titanium oxide manufactured by Ishihara Sangyo Co., Ltd. (surface treated with alumina + silica) Trade name: CR-90 (*17) Silica manufactured by Tosoh Silica Co., Ltd. Trade name: E-743 (average particle size 0.1μm)

The resin compositions of Examples 1 to 11 and Comparative Examples 1 to 7 obtained in this manner were evaluated as follows. These results are combined and shown in Table 1.

(Preparation of substrate for evaluation of heat resistance, etc.) The photosensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 to 6 were screen-printed on a solid copper substrate that was pretreated by polishing. Coat the entire surface so that the thickness becomes 30 μm to form a resin layer. After that, the resin layer was dried in a hot air circulation drying oven at 80°C for 30 minutes, and then an exposure device equipped with a metal halide lamp (HMW-680-GW20: ORC MANUFACTURING Co., Ltd.) was used to expose the resin layer at an exposure dose of 900 mJ/cm ² Exposure and development (30° C., 0.2 MPa, 1 mass % Na ₂ CO ₃ aqueous solution) were performed for 60 seconds. Thereafter, the resin layer was cured in a hot-air circulation drying oven at 150° C. for 60 minutes to form a cured coating film of the resin layer, and a substrate for evaluation of heat resistance and the like was produced.

The thermosetting resin compositions of Examples 9 to 11 and Comparative Example 7 were fully coated on a copper solid substrate pre-treated by polishing so that the film thickness after drying after screen printing became 30 μm to form a resin layer. . Thereafter, the resin layer was dried in a hot-air circulation drying oven at 80°C for 30 minutes, and then hardened in a hot-air circulation drying oven at 150°C for 60 minutes to form a cured coating film of the resin layer to produce a heat-resistant coating. and other evaluation substrates.

(Evaluation of heat resistance) Rosin-based flux was applied to each of the heat resistance evaluation substrates obtained above, and immersed in a solder bath set at 260°C for 5 seconds. Then, the flux was cleaned with denatured alcohol, and the expansion and peeling of the hardened coating were visually evaluated. The evaluation criteria for heat resistance are as follows. ○: The hardened coating has no expansion and peeling. ×: The hardened coating has expansion and peeling.

(Evaluation of reflectivity) The reflectivity at 450nm of the resin layer formed on each evaluation substrate for heat resistance obtained above was measured using a spectrophotometer (manufactured by Konica Minolta Co., Ltd., model: CM-5). The evaluation results are shown in the "After Curing" row in Table 1. The evaluation criteria for reflectivity are as follows. ◎: Reflectivity is 90% or more. ○: Reflectivity is 86% or more and less than 90%. ×: Reflectivity is less than 86%. In addition, the reflectivity of the resin layer on each evaluation substrate after the above heat resistance evaluation was also measured and evaluated using the same evaluation criteria as above. The evaluation results are shown in the "After Reflow" row in Table 1.

(Evaluation of warp) When preparing the substrate for the above-mentioned Tg measurement and evaluation, in the case of the photosensitive resin composition of Examples 1 to 8 and Comparative Examples 1 to 6, after development, the coating formed on the obtained copper foil is cut into 5cm×5cm pieces of each copper foil, and heat-cured in a hot air circulation drying furnace at 150°C for 60 minutes, and then returned to room temperature. After the cut 5×5cm pieces of the cured coating attached to each copper foil (hereinafter referred to as the sample) are placed on the operating table for 1 hour, the height from the surface of the operating table to the four end points of the sample is measured with a ruler, and the total is calculated. Each sample is tested three times in the same way, and the average value of the three tests is obtained. The evaluation results are shown in the "After Curing" row in Table 1. The evaluation criteria for warp are as follows. When making the above-mentioned substrate for Tg measurement and evaluation, in the case of the thermosetting resin composition of Examples 9 to 11 and Comparative Example 7, after drying, the coating formed on the obtained copper foil is cut into 5cm×5cm pieces of each copper foil, and heat-cured in a hot air circulation drying furnace at 150°C for 60 minutes and then returned to room temperature. After the cut 5×5cm pieces of each copper foil attached to the cured coating (hereinafter referred to as the sample) are placed on the operating table for 1 hour, the height from the surface of the operating table to the four end points of the sample is measured with a ruler, and the total is calculated. Each sample is tested three times in the same way, and the average value of the three tests is obtained. The evaluation results are shown in the "After Curing" row in Table 1. The evaluation criteria for warp are as follows. In addition, in this warp evaluation, copper foil is used as the base material of the evaluation substrate, not glass as exemplified in the subject of the present invention. Since glass is less likely to warp than copper foil, if the same test is conducted with the same size as the above sample, the warp value is too small and it is very difficult to make an evaluation judgment. Therefore, in order to make the evaluation judgment clear, a copper foil with large warp is used for the test. It is believed that if there is a warp reduction effect in this warp evaluation standard, there is also a sufficient warp reduction effect in the case of glass. ◎: The total height is less than 40mm. ○: The total height is 40mm or more and less than 60mm. △: The total height is 60mm or more and less than 80mm. ×: The total height is 80mm or more. Furthermore, regarding the above evaluation substrate, a reflow step was performed once using a reflow device (NIS-20-82C manufactured by Eightech Tectron) at a maximum temperature of 260°C. Afterwards, the reflectivity was measured and evaluated using the same criteria as the above evaluation. The evaluation results are shown in the "After Reflow" row in Table 1.

(Evaluation of electroless gold plating resistance) When preparing the substrate for evaluation of heat resistance and the like, in the case of the photosensitive resin compositions of Examples 1 to 8 and Comparative Examples 1 to 6, L/S ( A negative film with line width/space (line/space)=100/300μm is used to form a photoresist pattern (hardened coating film). When preparing the above-mentioned substrate for evaluation of heat resistance and the like, in the case of the thermosetting resin compositions of Examples 9 to 11 and Comparative Example 7, on a sulfuric acid-treated copper circuit pattern substrate with a thickness of 18 μm, a pattern with a diameter of 18 μm was formed by pattern printing. Photoresist pattern (hardened coating film) with 2mm opening. Thereafter, the obtained evaluation substrate was gold-plated using a commercially available electroless nickel plating bath and an electroless gold plating bath under the conditions of 5 μm nickel and 0.03 μm gold, and the presence or absence of peeling of the photoresist pattern layer and the presence or absence of penetration of the plating layer was evaluated. Then, the presence or absence of peeling of the photoresist pattern layer was evaluated by tape peeling. The evaluation criteria for electroless gold plating resistance are as follows. ○: Plating penetration and peeling of the photoresist pattern layer were not observed. △: Some slight penetration was observed after plating, and peeling of the photoresist pattern layer after stripping was also observed. ×: The photoresist pattern layer peeled off after plating.

As can be seen from the above, according to the present invention, a resin composition having both low warp and high reflectivity after the reflow step can be provided.

Claims (10)

A resin composition, characterized in that it is a resin composition containing (A) a carboxyl group-containing urethane resin and (E) a white colorant, In the dynamic viscoelasticity measurement of the hardened coating film at a frequency of 1Hz, The temperature (Tg) of the loss tangent peak is below 100℃, The peak of loss tangent is in the range of 0.5~1.5. The resin composition according to claim 1, wherein the white coloring agent (E) is titanium oxide. The resin composition according to claim 1, wherein the carboxyl group-containing urethane resin (A) is a carboxyl group-containing urethane resin that does not have an aromatic ring. The resin composition as described in claim 1, wherein (D) an epoxy resin is contained. The resin composition according to claim 1, which contains (F) other carboxyl group-containing resins in addition to the aforementioned (A) carboxyl group-containing urethane resin. A dry film having a resin layer obtained by coating the resin composition according to claim 1 into a film and drying the film. A hardened product obtained from the resin composition according to claim 1. A hardened product obtained from the dry film according to claim 6. An electronic component characterized by comprising the hardened material as claimed in claim 7. An electronic component characterized by having the hardened material according to claim 8.