TW202307056A - Curable resin composition, laminated structure, cured material and electronic component - Google Patents

Abstract

To provide a curable resin composition having characteristics that a dried coating film obtained has good resolution and that, even when cured materials after thermal curing are stored stacked under a high temperature environment, little sticking occurs. Provided is a curable resin composition which is alkali-developable and forms a cured film by light exposure and a heating treatment. When a dried film having a thickness of 2-100 [mu]m is formed from this curable resin composition, an arithmetic average roughness Ra of the dried film is less than 0.1 [mu]m, and an arithmetic average roughness Ra of a dried film after thermal curing of the dried film becomes 0.1 [mu]m to 1 [mu]m. The curable resin composition of the present invention has characteristics that a dried coating film obtained has good resolution and that, even when cured materials after thermal curing are stored stacked under a high temperature environment, little sticking occurs.

Description

Curable resin composition, laminated structure, cured product and electronic part

The present invention relates to a laminated structure of a resin layer formed of the curable resin composition, its cured product, and an electronic component having an insulating film formed of the cured product, and particularly relates to an alkali-developable and Curable resin composition forming a cured film by exposure and heat treatment, laminated structure of resin layers formed of the curable resin composition, cured product thereof, and electronic device having an insulating film formed of the cured product Component.

In the past, as a protective film for flexible printed wiring boards, a non-photosensitive resin structure obtained by applying a thermosetting adhesive to a thin film such as polyimide has been used. As a method of patterning a non-photosensitive resin structure to form a flexible printed wiring board, there has been a method of opening the hole by punching in the past, and then heat-pressing the flexible printed wiring board. method. Alternatively, there is also a method of directly pattern-printing a solvent-soluble thermosetting resin composition on a flexible printed wiring board, and then thermosetting to form a pattern. In particular, a polyimide film is used as a material suitable for a flexible printed wiring board because it has flexibility, heat resistance, mechanical properties, and electrical properties (see, for example, Patent Document 1). However, in the above-mentioned conventional method, the shape of the edge of the pattern will be collapsed due to the bleeding of the resin during coating or thermal pressing. It becomes difficult to form the fine patterns required by the chemical industry. [Prior Art Literature] [Patent Document]

[Patent Document 1] WO2012/133665 Publication

[Problems Solved by the Invention]

On the other hand, it is also considered that a known photosensitive solder resist can be used as a cover layer of a flexible printed wiring board as a circuit permanent protective film that can be finely processed. Since the photosensitive solder resist in the flexible printed wiring board can impart flexibility, it is necessary to lower the crosslink density. Since flexible substrates are thin and easy to bend, many sheets must be stacked and fixed before being stored or transported. The storage environment is increased to high temperature by the transportation environment, and when the photosensitive solder resist is used for the cover layer, since the area to protect the flexible printed wiring board is widened, the low cross-link density reduces the cross-linking density on the substrate. The formed coating films sometimes adhere to each other.

In addition, in recent years, there are increasing demands for thinner films in fields using rigid boards. Not only for flexible substrates, but also for thin substrates such as hard substrates with a thickness of 0.1mm, the phenomenon of coating films sticking to each other is similarly caused.

To solve this problem, when the surface roughness of the coating film is increased, the surface area to be contacted will be reduced, and no adhesion will occur. However, if a coating film with a large surface roughness is patterned by photolithography, halos will be caused on the surface of the coating film and sufficient resolution cannot be obtained.

The first object of the present invention in view of the above-mentioned problems is to provide a curable resin that has good resolubility of the dried coating film, good flexibility of the obtained cured product, and low adhesion when stored in a stack. Composition.

In addition, the second object of the present invention in view of the above-mentioned problems is to provide a case where the developability of the dried coating film is good, the heat resistance and flexibility of the obtained cured product are good, and the obtained cured product is stored in a stack. , A curable resin composition with low adhesion properties. [means to solve the problem]

The inventors of the present invention conducted detailed examinations in order to achieve the above-mentioned first object. As a result, the surface roughness (arithmetic mean roughness) can be kept small at the time of drying the coating film, and by using a curable resin composition that can increase the surface roughness (arithmetic mean roughness) after thermal curing , to obtain both high resolution of the dry coating film, flexibility and low adhesion of the thermosetting film, and complete the present invention. In addition, in this specification, the term "resolution property" refers to the expressiveness of details of an image obtained by alkaline development after exposing a resin layer made of the curable resin composition of the present invention.

That is, the above-mentioned first object of the present invention is a curable resin composition capable of alkali development and forming a cured film by exposure and heat treatment. When drying the coating film, the arithmetic mean roughness Ra of the dried coating film is less than 0.1 μm, and the arithmetic mean roughness Ra of the cured film after thermal curing of the dried coating film is 0.1 μm or more and 1 μm or less as the characteristic curability The resin composition (hereinafter also referred to as the curable resin composition of the first aspect of the present invention) can be achieved.

In this specification, the term "resolubility" refers to the fine detail representation of the image obtained by alkali development after pattern exposure of the resin layer made of the curable resin composition according to the first aspect of the present invention.

In addition, the curable resin composition of the first aspect of the present invention is such that when a dry coating film having a thickness of 2 to 100 μm is formed from the curable resin composition, the arithmetic mean roughness Ra of the dry coating film is less than 0.05 μm. , and the arithmetic average roughness Ra of the cured film after thermosetting of the aforementioned dry coating film is preferably not less than 0.1 μm and not more than 0.5 μm.

Furthermore, it is preferable to contain (A) alkali-soluble polyamideimide resin, (B) photobase generator, (C) thermosetting compound and (D) cellulose derivative.

Also, (C) the thermosetting compound is preferably an epoxy resin.

Therefore, the aforementioned first object of the present invention is a laminated structure supported or protected by a film at least one side of a resin layer formed with the curable resin composition of the present invention, the curable resin composition of the present invention Or a cured product of the resin layer of the laminated structure of the present invention, and an electronic component having an insulating film formed of the cured product of the present invention can also be realized.

Moreover, the inventors of the present invention conducted detailed examinations in order to achieve the above-mentioned second object. As a result, it has been found that by adding a cellulose derivative to a curable resin composition and adding a predetermined amount of an alkali-soluble polyimide resin, the adhesion between the obtained cured products is reduced, and the present invention has been completed.

That is, it was found that the aforementioned second object of the present invention can be obtained by containing (A) alkali-soluble polyamide imide resin, (B) photobase generator, (C) thermosetting compound and (D) cellulose The derivative is achieved by a characteristic curable resin composition (hereinafter also referred to as the curable resin composition of the second aspect of the present invention).

Also, the (A) alkali-soluble polyamideimide resin preferably has a carboxyl group, and the (A) alkali-soluble polyamideimide resin preferably has a carboxyl group and a phenolic hydroxyl group.

Furthermore, it is preferable that the curable resin composition of the second aspect of the present invention further contains (E) an alkali-soluble polyimide resin.

Therefore, (C) the thermosetting compound is preferably an epoxy resin.

Furthermore, the aforementioned second object of the present invention can be achieved by a cured product obtained from the curable composition of the present invention, and an electronic component having an insulating film formed of the cured product. [Effect of Invention]

According to the curable resin composition of the first aspect of the present invention, the resolution of the obtained dry coating film is good, and the flexibility of the cured product obtained after thermal curing is also good, and the cured product is stacked and placed on the It also has low adhesion characteristics when stored in a high-temperature environment. In addition, the curable composition of the second aspect of the present invention has good developability of the dried coating film, and the heat resistance and flexibility of the cured product obtained from the curable composition of the second aspect of the present invention are good, At the same time, it has low adhesion characteristics when stacked and stored.

[Types of implementing the invention] <The curable resin composition of the first aspect of the present invention>

The curable resin composition of the first aspect of the present invention is an alkali developable curable resin composition that can form a cured film by exposure and heat treatment, and a dry coating with a thickness of 2 to 100 μm is formed from the curable resin composition. The dry coating film has an arithmetic mean roughness Ra of less than 0.1 μm, and the dry coating film has an arithmetic mean roughness Ra of a cured film after thermal curing of 0.1 μm or more and 1 μm or less.

The curable resin composition of the first aspect of the present invention is alkali-developable, and is intended to form a cured film by exposure and heat treatment, and the constituent has an alkali-soluble functional group (hereinafter also referred to as an alkali-soluble group) ) compound (hereinafter also referred to as alkali-soluble compound) and (B) photobase generator and (C) thermosetting compound described later.

Among these, the (B) photobase generator can change the molecular structure by irradiation of ultraviolet light or visible light, or act as a combination of an alkali-soluble compound and (C) a thermosetting compound by cracking the molecule. The catalyst that forms the reaction performs its function.

As an alkali-soluble compound, the compound which has a phenolic hydroxyl group, the compound which has a carboxyl group, and the compound which has a phenolic hydroxyl group and a carboxyl group are mentioned, for example. The alkali-soluble compound is preferably the (A) alkali-soluble polyamideimide resin described later. Among them, as (A) alkali-soluble polyamide-imide resins, polyamide-imide resins having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) are also used. better.

The curable resin composition according to the first aspect of the present invention has a thickness of 2 to 100 μm and from the viewpoint of improvement in resolution, when forming a dried coating film of 3 to 80 μm, the arithmetic mean roughness of the dried coating film is preferably The thickness Ra is less than 0.1 μm, preferably less than 0.05 μm, and the arithmetic average roughness Ra of the cured film after thermal curing of the dried coating film is 0.1 μm to 1 μm, preferably 0.1 μm to 0.5 μm.

When the arithmetic average roughness Ra of a dry coating film is less than 0.1 micrometer, the random reflection of the light irradiated with a coating film at the time of exposure is suppressed, and resolution becomes favorable. Moreover, after thermosetting, by making the arithmetic mean roughness Ra of a cured film into 0.1 micrometer or more and 1 micrometer or less, small unevenness|corrugation will generate|occur|produce on a cured film. Due to the unevenness, the contact area between the cured films arranged in a stack becomes small, thereby reducing adhesion.

The unevenness of the dry coating film in the state of the dried coating film before heat curing is small, and the phenomenon that the unevenness on the cured film becomes larger after heat curing is considered to be because the curable resin composition of the present invention Produced by containing a polymer component that has a different miscibility with the above (C) thermosetting compound or alkali-soluble compound. That is, it is presumed that the polymer component dispersed in the dry coating film prior to thermosetting migrates to the film surface during the thermosetting reaction.

It is preferable to add (D) cellulose derivatives as this polymer component.

The curable resin composition of the first aspect of the present invention preferably contains (A) an alkali-soluble polyamide imide resin, (B) a photobase generator, (C) a thermosetting compound, and (D) ) cellulose derivatives.

<The curable resin composition of the second aspect of the present invention> The curable resin composition of the second aspect of the present invention contains (A) alkali-soluble polyamideimide resin, (B) photobase generator, (C) thermosetting compound, and (D) fiber prime derivatives.

The curable resin composition of the second aspect of the present invention preferably further contains (E) an alkali-soluble polyimide resin.

Therefore, (C) the thermosetting compound is preferably an epoxy resin.

[(A) Alkali-soluble polyamideimide resin] (A) Alkali-soluble polyamideimide resin is a preferable example of the above-mentioned alkali-soluble photocurable compound. (A) Alkali-soluble polyamideimide resins contain alkali-soluble groups (one or more of phenolic hydroxyl groups and carboxyl groups). The curable resin composition of the first aspect of the present invention preferably contains (A) an alkali-soluble polyamideimide resin, and the curable resin composition of the second aspect of the present invention contains (A) an alkali Soluble polyamide imide resin.

Such alkali-soluble polyamideimide resins include, for example, resins obtained by reacting a carboxylic acid anhydride component and an amine component to obtain an imide product, and then reacting the resulting imide product with an isocyanate component. Among them, the alkali-soluble group can be introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. Moreover, imidation may be performed by thermal imidation, chemical imidation may be performed, and these may be implemented in combination.

As the carboxylic acid anhydride component, there may be mentioned tetracarboxylic acid anhydride or tricarboxylic acid anhydride, etc., but it is not limited to these anhydrides. If it is a compound having an acid anhydride group and a carboxyl group that react with an amine group or an isocyanate group, it can be used. Derivatives. Moreover, these carboxylic anhydride components may be used individually or in combination.

As the amine component, diamines such as aliphatic diamines and aromatic diamines, polyvalent amines such as aliphatic polyetheramines, diamines having carboxyl groups, diamines having phenolic hydroxyl groups, and the like can be used. The amine component is not limited to these amines, and it is necessary to use an amine capable of introducing at least one functional group among a phenolic hydroxyl group and a carboxyl group. Moreover, these amine components may be used individually or in combination.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and their isomers or polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, or other general-purpose diisocyanates can be used. It is not limited to these isocyanic acids. Moreover, these isocyanate components can also be used individually or in combination.

(A) If the alkali-soluble polyamideimide resin is contained in the curable resin composition of the present invention, the alkali solubility (developability) of the polyamideimide resin is combined with the polyamide-imide-containing resin. From the point of view of maintaining a good balance of mechanical properties and other properties of the cured product of the amide imide resin, the acid value (acid value of solid content) is preferably 30 mgKOH/g or more, and 30 mgKOH/g to 30 mgKOH/g. 150mgKOH/g is preferred, and 50mgKOH/g-120mgKOH/g is particularly preferred. Specifically, when the acid value is set at 30 mgKOH/g or more, the alkali solubility, that is, the developability becomes good, and the crosslink density with the thermosetting component after light irradiation becomes high, and sufficient image contrast can be obtained. . In addition, by setting the acid value at 150 mgKOH/g or less, the so-called overheating in the PEB (POST EXPOSURE BAKE) step after light irradiation, which will be described later, can be suppressed and the process width can be increased.

In addition, (A) the molecular weight of the alkali-soluble polyamideimide resin is preferably 20,000 or less, more preferably 1,000 to 17,000, and 2,000 if the developability and cured coating film characteristics are considered. ~15,000 is better. If the molecular weight is less than 20,000, the alkali solubility of the unexposed part will increase, and the developability will be improved. On the other hand, when the molecular weight is 1,000 or more, sufficient development resistance and cured properties can be obtained for the exposed part after the exposure・PEB step.

(A) If the alkali-soluble polyamideimide resin is contained in the curable resin composition of the present invention, it is particularly used to have the structure shown in the following general formula (1) and the following general formula (2) A polyamideimide resin having the structure shown above is preferable from the viewpoint of further improving developability and improving flexibility and adhesiveness. Moreover, not only the structure represented by the general formula (1) and the structure represented by the following general formula (2) are contained in a molecule of (A) alkali-soluble polyamide imide resin, if contained in (A ) Alkali-soluble polyamideimide resins are sufficient.

(In general formula (1), _X1 is the residue of aliphatic diamine (a) (also referred to as "dipolymer diamine (a)" in this specification) derived from dimer acid having 24 to 48 carbon atoms. In the general formula (2), _X2 is the residue of an aromatic diamine (b) having a carboxyl group (also referred to as "carboxyl-containing diamine (b)" in this specification). For the general formula (1) And (2), Y are each independently cyclohexane or aromatic ring)

By containing the structure represented by the above-mentioned general formula (1) and the structure represented by the above-mentioned general formula (2), even in the case of using a mild alkaline solution such as a 1.0% by mass aqueous sodium carbonate solution, it can become a soluble alkali-soluble Excellent polyamide imide resin. Also, the cured product of the curable resin composition containing the polyamideimide resin can have excellent dielectric properties.

The dimer diamine (a) can be obtained by reductive amination of the carboxyl group in the dimer of an aliphatic unsaturated carboxylic acid having 12 to 24 carbon atoms. That is, the dimer diamine (a) of aliphatic diamine derived from dimer acid, for example, polymerizes unsaturated fatty acids such as oleic acid and linoleic acid to form a dimer acid, and after reducing this, the amine group obtained after transformation. As such an aliphatic diamine, commercial products, such as PRIAMINE 1073, 1074, 1075 (trade name made by Croda Japan) which have the diamine of C36 skeleton, can be used, for example. The dimer diamine (a) is preferably derived from a dimer acid having 28 to 44 carbon atoms, and more preferably derived from a dimer acid having 32 to 40 carbon atoms.

Specific examples of carboxyl group-containing diamine (b) include 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, 5,5'-methylenebis(o-aminobenzene formic acid), benzidine‐3,3'‐dicarboxylic acid, etc. The carboxyl group-containing diamine (b) may be composed of one type of compound, or may be composed of plural types of compounds. From the viewpoint of raw material availability, the carboxyl group-containing diamine (b) preferably contains 3,5-diaminobenzoic acid and 5,5'-methylenebis(anthranilic acid).

The relationship between the content of the structure represented by the general formula (1) and the content of the structure represented by the general formula (2) in the polyamideimide resin is not limited. From the point of view of good balance between the alkali solubility of polyamideimide resin and the mechanical properties of the cured product of the curable resin composition containing polyamideimide resin, dimer diamine The content (unit: mass %) of (a) is preferably 20 to 60 mass %, more preferably 30 to 50 mass %. In this specification, the "content of dimer diamine (a)" means the loading amount of dimer diamine (a) that is given a position as one of the raw materials when producing polyamide imide resin , The meaning of the ratio relative to the mass of the polyamide imide resin manufactured. Among them, "the quality of the manufactured polyamide imide resin" means that the water (H ₂ O ) and the value of the theoretical amount of carbon dioxide gas (CO ₂ ) produced in amidation.

From the viewpoint of improving the alkali solubility of the polyamideimide resin, in the above general formula (1) and the above general formula (2), the moiety represented by Y preferably has a cyclohexane ring. From the standpoint of good balance of other properties such as the alkali solubility of the polyamideimide resin and the mechanical properties of the hardened product of the resin composition containing the polyamideimide resin, the above-mentioned part indicated by Y The relationship between the amount of aromatic rings and cyclohexane rings is that the molar ratio of the content of cyclohexane rings to the content of aromatic rings is preferably 85/15 to 100/0, and 90/10 to 99 /1 is better, and 90/10 to 98/2 is more preferable.

The method for producing the above-mentioned (A) alkali-soluble polyamideimide resin is not particularly limited, and it can be produced through an imidization step and an imidization step using a known and usual method.

In the imidization step, the reaction is selected from dimer diamine (a), carboxyl-containing diamine (b), and cyclohexane‐1,2,4‐tricarboxylic acid‐1,2‐anhydride ( c) An imide compound obtained by grouping one or two species with trimellitic anhydride (d).

The loading amount of the dimer diamine (a) is preferably such that the content of the dimer diamine (a) becomes 20 to 60% by mass, and the content of the dimer diamine (a) becomes 30% by mass. The amount of ~50% by mass is preferable. The definition of the content of dimer diamine (a) is as above-mentioned.

If necessary, dimer diamine (a), carboxyl group-containing diamine (b), and other diamines may be used together. Specific examples of other diamines include 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]pyridine , bis[4-(4-aminophenoxy)phenyl]pyridine, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, bis[4-(4- Aminophenoxy)phenyl]methane, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[ 4-(4-aminophenoxy)phenyl]ketone, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2, 2'-Dimethylbiphenyl-4,4'-diamine, 2,2'-bis(trifluoromethyl)biphenyl-4,4'-diamine, 2,6,2',6 '-tetramethyl-4,4'-diamine, 5,5'-dimethyl-2,2'-sulfonyl-biphenyl-4,4'-diamine, 3,3'-diamine Hydroxybiphenyl-4,4'-diamine, (4,4'-diamino)diphenyl ether, (4,4'-diamino)diphenylene, (4,4'-di Amino)benzophenone, (3,3'-diamino)benzophenone, (4,4'-diamino)diphenylmethane, (4,4'-diamino)diphenyl Aromatic diamines such as base ether and (3,3'-diamino)diphenyl ether, such as hexamethylenediamine, octamethylenediamine, decamethylenediamine, dodecamethylenediamine, etc. Methyldiamine, octadecamethylenediamine, 4,4'-methylenebis(cyclohexylamine), isophoronediamine, 1,4-cyclohexanediamine, norbornenediamine and other aliphatic diamines.

From the viewpoint of improving the alkali solubility of polyamideimide resin, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) is preferred for the imidization step better. The molar ratio of the amount of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) relative to the amount of trimellitic anhydride (d) is preferably 85/15 to 100/0, 90/10 to 99/1 is preferred, and 90/10 to 98/2 is more preferred.

The amount of the diamine compound (specifically, the dimer diamine (a) and the carboxyl group-containing diamine (b) and other diamines used as necessary) used to obtain the imide, and the acid anhydride (specifically The relationship indicating the amount of one or two species selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) and trimellitic anhydride (d) is not limited. The usage-amount of an acid anhydride is preferably the quantity which becomes the molar ratio of 2.0-2.4 with respect to the usage-amount of a diamine compound, More preferably, it is the quantity which becomes 2.0-2.2.

In the amidoimidation step, a diisocyanate compound is reacted in the imidized product obtained by the above-mentioned imidization step to obtain a polyamidoamide containing a substance having a structure represented by the general formula (3) described later. imide resin.

The specific kind of diisocyanate compound is not specifically limited. The diisocyanate compound may consist of one type of compound, or may consist of plural types of compounds.

Specific examples of diisocyanate compounds include 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, naphthalene-1,5-diisocyanate, o- Aromatic diisocyanates such as xylylene diisocyanate, m-xylylene diisocyanate, 2,4-tertiary dimer; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate Aliphatic diisocyanate such as isocyanate, isophorone diisocyanate, norbornene diisocyanate, etc. From the point of view that the alkali solubility of (A) alkali-soluble polyamideimide resin and the light transmittance of polyamideimide resin can be improved at the same time, diisocyanate compounds containing aliphatic isocyanate are preferred. Preferably, the diisocyanate compound is preferably one containing aliphatic isocyanate.

The amount of the diisocyanate compound used in the amidoimidation step is not limited. From the viewpoint of imparting moderate alkali solubility to the polyamide imide resin, the amount of the diisocyanate compound used is a molar ratio of 0.3 to the amount of the diamine compound used to obtain the imide compound. The above is preferably 1.0 or less, more preferably 0.4 or more and 0.95 or less, and particularly preferably 0.50 or more and 0.90 or less.

(上述一般式(3)中，X各獨立為二胺殘基(二胺化合物之殘基)，Y各獨立為芳香環或環己烷環，Z為二異氰酸酯化合物之殘基。n為自然數)所示結構之物質。 The polyamide imide resin thus produced contains the following general formula (3)

(In the above general formula (3), each X is independently a diamine residue (residue of a diamine compound), each Y is independently an aromatic ring or a cyclohexane ring, and Z is a residue of a diisocyanate compound. n is a natural Number) The substance with the structure shown.

(A) Alkali-soluble polyimide resin and (E) Alkali-soluble polyimide resin of the optional components described below are combined in a calculated amount relative to 100 parts by mass of the curable resin composition of the present invention. , for example, not less than 10 parts by mass and not more than 85 parts by mass, preferably not less than 15 parts by mass and not more than 80 parts by mass, particularly preferably not less than 20 parts by mass and not more than 75 parts by mass.

[(B) Photobase Generator] The curable resin composition of the first aspect of the present invention contains (A) an alkali-soluble polyimide resin (and (E) an alkali-soluble polyimide resin as an optional component described later), (C) The thermosetting compound and (B) photobase generator are preferable, and the curable resin composition of the 2nd aspect of this invention contains (B) photobase generator. (B) The photobase generator changes the molecular structure by irradiation of ultraviolet light or visible light, or generates a catalyzer as an addition reaction between polyimide resin with carboxyl group and thermosetting component by cracking the molecule. A compound of one or more basic substances that mediates its function.

Examples of basic substances include secondary amines and tertiary amines.

Examples of photobase generators include α-aminoacetophenone compounds, oxime ester compounds, or compounds having an acyloxyimine group, an N-formylated aromatic amine group, or an N-acylated aromatic amine group. Compounds with substituents such as nitrobenzyl carbamate group, alkoxybenzyl carbamate group, etc. Among them, oxime ester compounds and α-aminoacetophenone compounds are also preferable. The α-aminoacetophenone compound is particularly preferably one having two or more nitrogen atoms.

As other photobase generators, WPBG-018 (trade name: 9-anthrylmethyl N, N'-diethylcarbamate; 9-anthrylmethyl N, N'-diethylcarbamate), WPBG-027 (trade name : (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine; (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine), WPBG -082 (trade name: guanidinium2-(3-benzoylphenyl)propionate; guanidinium 2-(3-benzoylphenyl) propionate), WPBG-140 (trade name: 1-(anthraquinon-2-yl; 1 -(anthraquinone-2-yl))ethyl imidazolecarboxylate; ethyl imidazole carboxylate) etc. (the above are manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The α-aminoacetophenone compound has a benzoin ether bond in the molecule, and when it is irradiated by light, it will cause cracks in the molecule to generate an alkaline substance (amine) that can act as a hardening catalyst.

As a specific example of the α-aminoacetophenone compound, (4-morpholinobenzoyl)-1-benzyl-1-dimethylaminopropane (Omnirad (Omnirad) 369, trade name , manufactured by IGM Resins) or 4-(methylthiobenzoyl)-1-methyl-1-morpholinoethane (Omnirad 907, trade name, manufactured by IGM Resins), 2-(dimethyl Amino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (Omnirad 379, trade name, IGM Resins company Manufactured) and other commercially available compounds or solutions.

As the oxime ester compound, any compound can be used as long as it can generate a basic substance by light irradiation. As the oxime ester compound, an oxime ester-based photobase generator having a group represented by the following general formula (4) is preferred.

(In the formula, _R1 represents a hydrogen atom, unsubstituted or phenyl substituted by an alkyl group with 1 to 6 carbons, phenyl or a halogen atom, unsubstituted or substituted by one or more hydroxyl groups with 1 to 20 carbons Alkyl group, the alkyl group interrupted by one or more oxygen atoms, unsubstituted or substituted by an alkyl group with 1 to 6 carbons or a cycloalkyl group with 5 to 8 carbons substituted by phenyl, unsubstituted or substituted by carbon Alkyl or benzoyl with 2 to 20 carbons substituted by alkyl with 1 to 6 carbons or phenyl, _R2 represents unsubstituted or substituted by alkyl with 1 to 6 carbons, phenyl or halogen Substituted phenyl, unsubstituted or substituted by 1 or more hydroxyl groups with 1 to 20 carbons, such alkyl groups interrupted by 1 or more oxygen atoms, unsubstituted or 1 to 6 carbons alkyl groups Or a cycloalkyl group with 5 to 8 carbons substituted by a phenyl group, or an alkyl group or a benzoyl group with 2 to 20 carbons that is unsubstituted or substituted by an alkyl group with 1 to 6 carbons or a phenyl group.) Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan Co., Ltd., N-1919 and NCI-831 manufactured by ADEKA Corporation etc. are mentioned as a commercial item of an oxime ester type photobase generator. Also, a compound having two oxime ester groups in the molecule as described in Japanese Patent No. 4344400 can also be used.

Other examples include JP-A No. 2004-359639, JP-A No. 2005-097141, JP-A No. 2005-220097, JP-A 2006-160634, JP-A 2008-094770, Japan The carbazole oxime ester compound etc. which are described in JP-A-2008-509967, JP-A-2009-040762, JP-A-2011-80036, etc.

Such a photobase generator may be used individually by 1 type, and may use it in combination of 2 or more types. The amount of (B) photobase generator in the curable resin composition of the present invention is based on 100 parts by mass of (A) alkali-soluble polyamideimide resin, or containing alkali-soluble polyamideimide resin. In the case of an imide resin, with respect to 100 parts by mass of the total amount of (A) alkali-soluble polyimide imide resin and alkali-soluble polyimide resin, for example, 0.1 mass part or more 40 mass parts Part or less, preferably 0.2 to 20 parts by mass.

When it is 0.1 mass part or more, favorable contrast of the image development resistance of a light-irradiated part/non-irradiated part can be obtained. Moreover, when it is 40 mass parts or less, the characteristic of hardened|cured material can be improved.

[(C) thermosetting compound] The curable resin composition of the first aspect of the present invention preferably contains (C) a thermosetting compound from the viewpoint of imparting heat resistance and chemical resistance to the cured product after thermosetting. The curable resin composition of the second aspect contains (C) a thermosetting compound.

(C) Epoxy resins, urethane resins, polyester resins, polyurethanes containing hydroxyl groups, amino groups or carboxyl groups, polyesters, polycarbonates, polyols, etc. can be used as thermosetting compounds. Commonly known thermosetting resins such as phenoxy resins, acrylic copolymer resins, vinyl resins, oxazine resins, and cyanate resins are used.

Among them, epoxy resin is preferable as (C) thermosetting compound from the viewpoint of heat resistance and chemical resistance.

Specific examples of epoxy resins include jER828 manufactured by Mitsubishi Chemical Corporation, EHPE3150 manufactured by Daicel Chemical Industries, Ltd., EPICLON 840 manufactured by DIC Corporation, EpotohtoYD-011 manufactured by Nippon Steel Chemical & Materials Co., Ltd., and Dow/Chemicals Corporation. D.E.R.317 manufactured by Sumitomo Chemical Corporation, SumiepoxyESA-011 manufactured by Sumitomo Chemical Co., Ltd., etc. (all are trade names) bisphenol A type epoxy resin; jERYL903 manufactured by Mitsubishi Chemical Corporation, EPICLON152 manufactured by DIC Corporation, manufactured by Nippon Steel Chemical & Materials Brominated epoxy resins such as EpotohtoYDB-400, D.E.R.542 manufactured by Dow/Chemicals, SumiepoxyESB-400 manufactured by Sumitomo Chemical Co., Ltd. (all are trade names); jER152 manufactured by Mitsubishi Chemical Corporation, D.E.N.431 manufactured by Dow/Chemicals Corporation , Epiclon N-730 manufactured by DIC Corporation, EpotohtoYDCN-701 manufactured by Nippon Steel Chemical & Materials Co., Ltd., EPPN-201 manufactured by Nippon Kayaku Co., Ltd., SumiepoxyESCN-195X manufactured by Sumitomo Chemical Co., Ltd. (all are trade names) novolac Bisphenol F epoxy resins such as EPICLON830 manufactured by DIC Corporation, jER807 manufactured by Mitsubishi Chemical Corporation, EpotohtoYDF-170, YDF-175, YDF-2004 manufactured by Nippon Steel Chemical & Materials Co., Ltd. (all trade names) Resin: Hydrogenated bisphenol A type epoxy resin such as Epotohto ST-2004 (trade name) manufactured by Nippon Steel Chemical & Materials Co., Ltd.; jER604 manufactured by Mitsubishi Chemical Corporation, Epotohto YH-434 manufactured by Nippon Steel Chemical & Materials Co., Ltd., manufactured by Sumitomo Chemical Co., Ltd. SumiepoxyELM-120 and the like (both are trade names) of glycidyl amine type epoxy resins; hydantoin type epoxy resins; Daicel Chemical Industries, Ltd. CELLOXIDE2021 etc. (both are trade names) Epoxy resin; trihydroxyphenylmethane type epoxy resins such as EPPN-501 (all trade names) manufactured by Nippon Kayaku Corporation; YL-6056, YX-4000, YL-6121 (all trade names) manufactured by Mitsubishi Chemical Corporation Bixylenol-type or bisphenol-type epoxy resins or their mixtures; EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by ADEKA Corporation, EXA-1514 (trade name) manufactured by DIC Corporation, etc. Phenol S-type epoxy resin; bisphenol A novolak type epoxy resin such as jER157S (trade name) manufactured by Mitsubishi Chemical Corporation; heterocyclic epoxy resin such as TEPIC manufactured by Nissan Chemical Co., Ltd. (both trade names); Phenyl novolac epoxy resin; Japan Naphthyl-containing epoxy resins such as ESN-190 manufactured by Iron Chemical & Materials Co., Ltd., and HP-4032 manufactured by DIC Corporation; epoxy resins having a dicyclopentadiene skeleton such as HP-7200 manufactured by DIC Corporation, etc.

(C) Thermosetting compounds can also be mixed in any amount, but (A) alkali-soluble polyimide resin and when contained, the equivalent ratio (alkali-soluble polyimide resin) to alkali-soluble polyimide resin Reactive group: thermosetting group such as epoxy group) is preferably compounded at a ratio of 1:0.1 to 1:10.

[(D) Cellulose derivatives] The curable resin composition according to the first aspect of the present invention contains (D) cellulose as a polymer component different in compatibility with the above-mentioned (C) thermosetting compound or alkali-soluble photocurable compound. A derivative is preferable, and the curable resin composition of the second aspect of the present invention contains (D) a cellulose derivative. When the (D) cellulose derivative is contained in the curable resin composition of the present invention, the (D) cellulose derivative is soluble in an organic solvent and preferably has a high glass transition temperature (Tg). Examples of (D) cellulose derivatives include cellulose ethers, carboxymethyl cellulose, cellulose esters and the like which will be described later.

Examples of cellulose ethers include ethyl cellulose, hydroxyalkyl cellulose, and the like, and examples of commercially available ethyl cellulose include Etocell (registered trademark) 4, Etocell 7, Etocell 10, Etocell 14, Etocell 20, Etocell 45, Etocell 70, Etocell 100, Etocell 200, Etocell 300 (all are trade names manufactured by Dow/Chemicals Co.), as commercial products of hydroxyalkylcellulose, MetrosSM, Metros60SH, Metros65SH, Metros90SH, MetrosSEB, MetrosSNB (all are Shin-Etsu Chemicals) Trade name of industrial (stock) system), etc.

Also, commercial products of carboxymethylcellulose include CMCAB-641-0.2 (trade name manufactured by Eastman Chemical Co.), SunroseF, SunroseA, SunroseP, SunroseS, and SunroseB (all Nippon Paper Co., Ltd. manufactured trade name), etc.

(式(5)中，R ₁、R ₂及R ₃各獨立為氫、醯基，或式(6)

(式(6)中，R ₄為氫或甲基，R ₅為氫、甲基、乙基或縮水甘油基。)所表示，R ₁、R ₂及R ₃的至少1個為氫，n為1以上的整數，該上限由後述分子量所限制)所示化合物。 More preferable cellulose derivatives are cellulose esters in which the hydroxyl groups of cellulose are esterified with organic acids, specifically the following formula (5)

(In formula (5), R ₁ , R ₂ and R ₃ are each independently hydrogen, acyl, or formula (6)

(In formula (6), R ₄ is hydrogen or methyl, and R ₅ is hydrogen, methyl, ethyl or glycidyl.) Represented, at least one of R ₁ , R ₂ and R ₃ is hydrogen, n is an integer of 1 or more, and the upper limit is limited by the molecular weight described later).

For the cellulose ester represented by the above formula (5), the content of the acyl group relative to the cellulose resin is in the range of more than 0 and not more than 60 wt%, preferably in the range of 5 to 55 wt%.

For the cellulose ester represented by the above formula (5), the content of the hydroxyl group relative to the cellulose resin is 0-6 wt%, as the acyl group, the content of the acetyl group is 0-40 wt%, the propionyl group or/and The content of butyryl group is 0-55wt%, and the content of the group represented by formula (6) is preferably in the range of 0-20wt%. The so-called "wt%" means the weight % of hydrogen, acyl group or group represented by formula (6) relative to the weight of cellulose.

Examples of commercially available cellulose esters include CA-398-3, CA-398-6, CA-398-10, CA-398-30, CA-394-60S, etc. , as cellulose acetate butyrate, CAB-551-0.01, CAB-551-0.2, CAB-553-0.4, CAB-531-1, CAB-500-5, CAB-381-0.1, CAB-381-0.5, CAB-381-2, CAB-381-20, CAB-381-20BP, CAB-321-0.1, CAB-171-15, etc., as cellulose acetate propionate, include CAP-504-0.2, CAP-482-0.5, CAP-482-20 (the above-mentioned cellulose derivatives are all trade names manufactured by Eastman Chemical Company) and the like. Among these, cellulose acetate butyrate and cellulose acetate propionate are preferable from the viewpoint of solubility in solvents. Furthermore, the above-mentioned cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are mixed with (meth)acrylic acid, (Meth)acrylic acid methyl group, (meth)acrylic acid ethyl group, (meth)acrylic acid glycidyl group etc. are reacted, and the cellulose derivative containing the group represented by formula (6) can be obtained. By using the cellulose derivative containing the group represented by this formula (6), the adhesiveness evaluation result can become more favorable.

(D) The number average molecular weight of the cellulose derivative is not particularly limited, but is preferably 5,000-500,000, more preferably 10,000-100,000, more preferably 10,000-30,000. When the molecular weight is within the above-mentioned range, the adhesion is small, that is, the evaluation result of adhesion becomes good, and the viscosity of the curable resin composition is in an appropriate range.

In addition, the glass transition temperature Tg in this specification is the glass transition temperature measured according to the method described in "5.17.5DSC method" of JISC6481:1996 by thermomechanical analysis (DSC).

When the cellulose derivative used in the present invention is derived from natural products, it is preferable from the perspective of fossil fuel depletion. Moreover, the starting raw materials used in the cellulose derivatives of the present invention can also be produced from recycled products such as recycled pulp, which can also provide a better composition from the environmental perspective of reducing CO ₂ .

(D) The cellulose derivative can be used individually or in mixture of 2 or more types. (D) The compounding quantity of a cellulose derivative is 100 mass parts with respect to 100 mass parts of (A) alkali-soluble polyimide resin (and the alkali-soluble polyimide resin of the optional component mentioned later), for example: 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, more preferably 4 to 10 parts by mass. In the case of the above range, when the coating film is dried, the surface roughness (arithmetic mean roughness Ra) can be reduced to less than 0.1 μm, and the adhesion is small, that is, the evaluation result of adhesion becomes good, and the curability The viscosity of the resin composition is in an appropriate range. This is considered to be that (A) alkali-soluble polyamideimide resin, (C) thermosetting compound and (D) cellulose derivatives have good compatibility before thermosetting, and the polymer components are dispersed Because of the way it exists in the dry coating film. In addition, it can be considered that the polymer component that exists in a dispersed form in the dry coating film after thermosetting moves to the surface of the film during the thermosetting reaction, and the surface roughness (arithmetic mean roughness) of the cured film after thermosetting Ra) is increased by drying the coating film before heat curing. If the number average molecular weight and compounding amount of (D) cellulose derivatives are set within the above range, the surface roughness (arithmetic average roughness) after curing Ra) may be 0.1 μm or more and 1 μm or less.

[(E) Alkali-soluble polyimide resin] The curable resin composition of the present invention preferably contains (E) an alkali-soluble polyimide resin from the viewpoint of heat resistance.

(E) The alkali-soluble polyimide resin has an alkali-soluble functional group (hereinafter also referred to as an alkali-soluble group). The so-called alkali-soluble functional group is a functional group capable of developing the curable resin composition of the present invention in an alkaline solution, for example, carboxyl group and phenolic hydroxyl group.

Examples of such (E) alkali-soluble polyimide resins include resins obtained by reacting a carboxylic anhydride component, an amine component, and/or an isocyanate component. Among them, the above-mentioned alkali-soluble group can be introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. Moreover, imidization may be performed by thermal imidization, chemical imidation may be performed, and these may be implemented in combination.

As the carboxylic anhydride component, tetracarboxylic anhydride or tricarboxylic anhydride can be mentioned, but it is not limited to these anhydrides, as long as it is a compound having an acid anhydride group and a carboxyl group that react with an amine group or an isocyanate group, it can be used. The derivative. Moreover, these carboxylic anhydride components may be used individually or in combination.

As the amine component, diamines such as aliphatic diamines and aromatic diamines, polyvalent amines such as aliphatic polyetheramines, diamines having carboxyl groups, diamines having phenolic hydroxyl groups, and the like can be used. The amine component is not limited to these amines, but it is necessary to use an amine capable of introducing at least one functional group among a phenolic hydroxyl group and a carboxyl group. Moreover, these amine components may be used individually or in combination.

As the isocyanate component, diisocyanates such as aromatic diisocyanates and their isomers or polymers, aliphatic diisocyanates, alicyclic diisocyanates and their isomers, or other general-purpose diisocyanates can be used. It is not currently limited to these isocyanates. Moreover, these isocyanate components can also be used individually or in combination.

For the synthesis of such (E) alkali-soluble polyimide resin, known and commonly used organic solvents can be used. As the organic solvent, there is no problem as long as it does not react with the carboxylic anhydrides, amines, and isocyanates of the raw materials and can dissolve these raw materials, and it is not particularly limited to this structure. Especially from the viewpoint of high solubility of raw materials, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl Aprotic solvents such as acetone and γ-butyrolactone.

(E) The alkali-soluble polyimide resin preferably has a carboxyl group as an alkali-soluble group, and particularly preferably has both a carboxyl group and a phenolic hydroxyl group as an alkali-soluble group.

(E) Alkali-soluble polyimide resins have other characteristics such as the alkali solubility (developability) of polyimide resins, and the mechanical properties of cured products of curable resin compositions containing polyimide resins. From the viewpoint of good balance, the acid value (acid value of solid content) is preferably 20 to 200 mgKOH/g, and particularly preferably 60 to 150 mgKOH/g.

In addition, if the molecular weight of the alkali-soluble polyimide resin is considered in terms of developability and cured coating film properties, the mass average molecular weight Mw is preferably 100,000 or less, more preferably 1,000-100,000, and more preferably 2,000-50,000 .

(E) When an alkali-soluble polyimide resin is added, from the viewpoint of improving heat resistance and developability, as (A) alkali-soluble polyamideimide resin and (E) alkali-soluble The mixing ratio of the polyimide resin can be set at a mass ratio of 98:2 to 50:50, preferably at 95:5 to 50:50, and preferably at 95:5 to 70:30 better.

In the curable resin composition of the present invention, the following components may be further added as necessary.

[polymer resin] The curable resin composition of the present invention may contain known and conventional polymer resins for the purpose of improving the flexibility and dry-to-touch property of the resulting cured product. Examples of such polymer resins include polyester-based polymers, phenoxy resin-based polymers, polyvinyl acetal-based polymers, polyvinyl butyral-based polymers, polyamide-based polymers, and elastomers. Such a polymer resin may be used individually by 1 type, and may use 2 or more types together.

[Inorganic Filler] In the curable resin composition of the present invention, an inorganic filler can be added when it is desired to suppress curing shrinkage of the cured product and improve characteristics such as adhesion and hardness. Examples of such inorganic fillers include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, alumina, aluminum hydroxide, silicon nitride , aluminum nitride, boron nitride, Newburg siliceous soil, etc.

[Colorant] The curable resin composition of the present invention can be added with known and commonly used coloring agents such as red, orange, blue, green, yellow, white, and black. Any of pigments, dyes, and pigments may be used as the coloring agent.

[Organic solvents] An organic solvent may be added to the curable resin composition of the present invention when preparing the resin composition or adjusting the viscosity of coating on a substrate or a carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum-based solvents, and the like. Such an organic solvent may be used individually by 1 type, and may use it as a mixture of 2 or more types.

[other ingredients] The curable resin composition of the present invention may further add components such as mercapto compounds, adhesion promoters, antioxidants, and ultraviolet absorbers as necessary. These can use known conventions.

In addition, well-known and commonly used tackifiers such as micropowdered silicon dioxide, hydrotalcite, organic bentonite, and montmorillonite, defoamers such as silicon oxide, fluorine, and polymer systems and/or leveling agents, and silane coupling agents can be added. Commonly used additives such as mixtures and antirust agents.

＜Laminated structure＞ In the laminated structure of the present invention, at least one side of the resin layer formed of the curable resin composition of the present invention is supported or protected by a film.

The resin layer may be a single layer or a laminated structure having two or more resin layers. In the case of a laminated structure of two or more resin layers, for example, a resin layer formed of the curable resin composition of the present invention may be laminated, or a resin layer formed of the curable resin composition of the present invention may be used. , a laminated structure with a resin layer not formed of the curable resin composition of the present invention.

In the case of the latter laminated structure, the laminated structure has, for example, a resin layer (A) provided on a substrate such as a flexible printed wiring board, and a resin layer (B) provided on the resin layer (A). At least one side of the resin layer of the laminated structure is supported or protected by a film. The resin layer (A) can be formed of, for example, an alkali-developing resin composition containing an alkali-soluble resin and a heat-reactive compound.

The above-mentioned laminated structure can be produced as follows, for example.

That is, first, on a carrier film (support film), the curable resin composition of the present invention constituting the resin layer is diluted with an organic solvent to adjust to an appropriate viscosity, and coated by a known method such as a chipping wheel coater according to a conventional method. When the resin layer has a laminated structure, the coated resin composition is replaced, or the coating operation is repeated without replacement. After drying at a temperature of usually 50-130°C for 1-30 minutes, a dry coating film of the resin layer in the B-stage state (semi-cured state) is formed on the carrier film to produce the laminated structure of the present invention. The resin layer of the laminate structure is a so-called dry film. On this dry film, a peelable coating film (protective film) may be further laminated for the purpose of preventing dust from adhering to the surface of the dry coating film. As the carrier film and the cover film, known plastic films in the past can be used. For the cover film, when the cover film is peeled off, the adhesive force between the resin layer and the carrier film is better. There is no particular limitation on the thickness of the carrier film and the covering film, and generally the range of 10-150 μm can be appropriately selected.

＜hardened material＞ 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 laminated structure of the present invention.

＜Electronic parts＞ For the curable resin composition of the present invention and the resin layer of the laminated structure of the present invention, for example, those effective for electronic components such as flexible printed wiring boards can be used. Specifically, it is possible to form a layer of the curable resin composition of the present invention on a flexible printed wiring base material or a resin layer of a laminated structure. Flexible printed wiring boards made of hardened insulating films.

Hereinafter, the manufacturing method of the flexible printed wiring board is demonstrated concretely.

＜Manufacturing method of flexible printed wiring board＞ An example of production of a flexible printed wiring board using the curable resin composition of the present invention or the resin layer of the laminated structure of the present invention is shown below. That is, it includes a step of forming a resin layer by applying the curable resin composition of the present invention to a flexible printed wiring substrate forming a conductor circuit, or laminating the resin layer of the laminated structure of the present invention (layer forming step) . A step of irradiating the resin layer with active energy rays to form a pattern (exposure step), and a step of alkali developing the exposed resin layer to form a patterned resin layer image (development step) Manufacturing method. In addition, after alkaline development if necessary, further photocuring or thermosetting (post-curing step), the resin layer is completely cured to form a cured film to obtain a highly reliable flexible printed wiring board.

Moreover, manufacture of the flexible printed wiring board using the curable resin composition of this invention or the resin layer of the laminated structure of this invention can also be performed according to another procedure. That is, it includes a step of forming a resin layer by applying the curable resin composition of the present invention to a flexible printed wiring substrate forming a conductor circuit, or laminating the resin layer of the laminated structure of the present invention (layer forming step) , a step of irradiating the resin layer with active energy rays into a pattern shape (exposure step), a step of heating the exposed resin layer (heating (PEB) step), and subjecting the heated resin layer to alkali development to form A method for producing a patterned resin layer image step (development step). Also, after alkaline development if necessary, further photocuring or thermal curing (post-curing step) is performed to completely cure the resin layer to form a cured film, and a highly reliable flexible printed wiring board can be obtained. [Example]

Examples are shown below and the present invention will be specifically described, but the present invention is not limited only to these Examples. In addition, unless otherwise specified below, "parts" means parts by mass of solid content.

((A) Synthesis of Alkali Soluble Polyamideimide Resin) [Synthesis Example 1] In a four-necked 300mL flask equipped with a nitrogen gas introduction tube, a thermometer, and a stirrer, 28.61 g (0.052 mol), 4.26 g (0.028 mol) of 3,5-diaminobenzoic acid as the carboxyl group-containing diamine (b), and 85.8 g of γ-butyrolactone were charged and dissolved at room temperature.

Next, 30.12 g (0.152 mol) of cyclohexane-1,2,4-tricarboxylic anhydride (c) and 3.07 g (0.016 mol) of trimellitic anhydride (d) were charged and kept at room temperature for 30 minutes. Further, 30 g of toluene was added, and the temperature was raised to 160° C., water co-produced with toluene was removed, held for 3 hours, and cooled to room temperature to obtain a solution containing imide.

14.30 g (0.068 mol) of trimethylhexamethylene diisocyanate, which is a diisocyanate compound, was charged into the solution containing the obtained imidate, and kept at a temperature of 160°C for 32 hours. After diluting 21.4 g of ketones, a solution (A-1) containing (A) an alkali-soluble polyamideimide resin was obtained. The obtained polyamideimide resin had a mass average molecular weight Mw of 5250, a solid content of 41.5% by mass, an acid value of 63 mgKOH/g, and a dimer diamine (a) content of 40.0% by mass.

[Synthesis Example 2] In a four-necked 300mL flask equipped with a nitrogen gas introduction tube, a thermometer, and a stirrer, as the dimer diamine (a), an aliphatic diamine derived from a dimer acid having 36 carbon atoms (manufactured by Croda Japan, product name PRIAMINE1075) 29.49 g (0.054 mol), 4.02 g (0.026 mol) of 3,5-diaminobenzoic acid as the carboxyl group-containing diamine (b), and 73.5 g of γ-butyrolactone were charged and dissolved at room temperature.

Next, 31.71 g (0.160 mol) of cyclohexane-1,2,4-tricarboxylic anhydride (c) and 1.54 g (0.008 mol) of trimellitic anhydride (d) were charged and kept at room temperature for 30 minutes. Furthermore, 30 g of toluene was added, the temperature was raised to 160° C., water co-produced with toluene was removed, the mixture was kept for 3 hours, and after cooling to room temperature, a solution containing imide was obtained.

6.90 g (0.033 mol) of trimethylhexamethylene diisocyanate and 8.61 g (0.033 mol) of dicyclohexylmethane diisocyanate were charged as diisocyanate compounds into the solution containing the obtained imidate, and the The temperature at °C was maintained for 32 hours, and after diluting with 36.8 g of cyclohexanone, a solution (A-2) containing (A) alkali-soluble polyamideimide resin was obtained. The mass average molecular weight Mw of the obtained polyamideimide resin was 5840, the solid content was 40.4 mass %, the acid value was 62 mgKOH/g, and the content of dimer diamine (a) was 40.1 mass %.

[Synthesis Example 3] In a four-necked 300mL flask equipped with a nitrogen inlet tube, a thermometer, and a stirrer, 6.98g of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 3,5-diaminobenzoin 3.80 g of acid, 8.21 g of polyether diamine (manufactured by Huntsman, product name Erastamin RT1000, molecular weight: 1025.64), and 86.49 g of γ-butyrolactone were charged and dissolved at room temperature.

Next, 17.84 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and 2.88 g of trimellitic anhydride were charged and kept at room temperature for 30 minutes. Further, 30 g of toluene was added, the temperature was raised to 160° C., water co-produced with toluene was removed, the mixture was kept for 3 hours, and after cooling to room temperature, an imide solution was obtained.

9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were placed in the obtained imide solution, and the temperature of 160° C. was maintained for 32 hours. In this way, the carboxyl group-containing (A) alkali-soluble polyamideimide resin solution (A-3) was obtained. The solid content was 40.1% by mass, and the acid value was 83 mgKOH/g.

((E) Synthesis of alkali-soluble polyimide resin) [Synthesis Example 4] In a separable 3-neck flask equipped with a stirrer, nitrogen introduction tube, fractionation ring, and cooling ring, add 22.4 g of 3,3'-diamino-4,4'-dihydroxydiphenylsulfone, 2,2'- Bis[4-(4-aminophenoxy)phenyl]propane 8.2g, NMP30g, γ-butyrolactone 30g, 4,4'-oxydiphthalic anhydride 27.9g and trimellitic anhydride 3.8g, in Stirring was performed at room temperature for 4 hours at 100 rpm under a nitrogen atmosphere. Next, 20 g of toluene was added, and the toluene and water were distilled off at 150 rpm in a silicone bath at a temperature of 180° C., while stirring for 4 hours to obtain a polyimide resin solution (PI-1) having phenolic hydroxyl and carboxyl groups.

The acid value of the obtained resin (solid content) was 18 mgKOH, Mw was 10,000, and the hydroxyl equivalent was 390.

((D) Synthesis of cellulose derivatives) [Synthesis Example 5] In a flask equipped with a stirrer, a thermometer, and a reflux cooler, put 64 g of methyl ethyl ketone and 16 g of CAB-553-0.4 (cellulose acetate derivative, manufactured by Eastman Chemical Co.) at 75° C. Stirring was carried out for 1 hour. Next, a mixture obtained by previously mixing 15 g of methyl methacrylate and 1 g of benzoyl peroxide was dropped over 3 hours. After completion of the dropping, a mixture obtained by mixing 0.5 g of benzoyl peroxide and 5 g of methyl ethyl ketone in advance was dropped over 1 hour while maintaining the temperature at 75°C. And continue stirring at 75° C. for 3 hours and then cool. 61 g of methyl ethyl ketone was added to the mixture and stirred to obtain a resin solution (CA-1). And the heating residue of resin solution CA-1 was 20.0 mass %.

[Synthesis Example 6] In a flask equipped with a stirrer, a thermometer, and a reflux cooler, 64 g of methyl ethyl ketone and 16 g of CAB-553-0.4 (cellulose acetate derivatives, manufactured by Eastman Chemical Co.) were charged, and 1 Stir for an hour. Next, a mixture obtained by previously mixing 15 g of glycidyl methacrylate and 1 g of benzoyl peroxide was dripped over 3 hours. After completion of the dropping, a mixture obtained by mixing 0.5 g of benzoyl peroxide and 5 g of methyl ethyl ketone in advance was dropped over 1 hour while maintaining the temperature at 75°C. And continue stirring at 75° C. for 3 hours and then cool. 61 g of methyl ethyl ketone was added to the mixture and stirred to obtain a resin solution (CA-2). Moreover, the heating residue of resin solution CA-2 was 20.0 mass %.

[Example of the curable resin composition of the first aspect of the present invention] <1-1. Preparation of Curable Resin Compositions of Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3> According to the component composition shown in the following Table 1, add each material of the curable resin composition of Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3, pre-mix this with a mixer, and then Kneading with 3 roller mills to adjust each curable resin composition to form a resin layer. In addition, the values in Table 1 represent parts by mass of solid content unless otherwise specified.

For each curable resin composition mentioned above, a resin layer (dry coating film) in the B-stage state (semi-cured state) of each curable resin composition was formed as shown below, and the resolution was evaluated. As will be described later, the B-stage state (semi-cured state)/thermal The surface roughness of each coating film after hardening. Therefore, the heat resistance (soldering heat resistance), gold plating resistance (chemical resistance), flexibility and adhesiveness of the flexible wiring board having a cured product of the resin layer were also evaluated. The results are shown in Table 1.

<1-2. Formation of resin layer> A flexible printed wiring substrate with a circuit having a copper thickness of 18 μm was prepared, and pre-processed using CZ-8100 from MEC. Thereafter, each curable resin composition obtained in Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 was applied to the pretreated flexible printed wiring substrate until it was dried. The film thickness was the film thickness described in Table 1. Thereafter, after drying at 90° C. for 30 minutes in a hot-air circulation drying oven, a resin layer (dried coating film) in a B-stage state (semi-cured state) was formed.

<1-3. Production of Evaluation Board> For the uncured resin layer on each flexible printed wiring substrate forming the above resin layer, first use an exposure device equipped with a metal halide lamp (HMW-680-GW20: Oak Manufacturing Co., Ltd.), through a negative mask (Negative mask), pattern exposure was performed at 300mJ/cm ² to form an opening with a diameter of 200μm. Thereafter, after the PEB step was performed at 90°C for 30 minutes, development (30°C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution) was carried out for 60 seconds, and a hardened form was produced by thermal curing at 150°C for 60 minutes. A flexible printed wiring board (evaluation board) with a resin layer (cured coating film).

＜1-4. Evaluation of Surface Roughness＞ For the resin layer (dry coating film) in the B-stage state (semi-hardened state) formed on the flexible printed wiring substrate as described in <1-2. Formation of resin layer>, or for .Preparation of the evaluation substrate>The arithmetic average surface roughness Ra was measured for the resin layer on the evaluation substrate prepared as described above after thermosetting. The measured value is the average value of arbitrary 5 points in the observation range of 100×100 μm. For the measurement of the arithmetic mean surface roughness Ra, a shape measurement laser microscope (VK-X100 manufactured by Keyence Co., Ltd.) was used. After starting the shape measurement laser microscope (same as VK-X100) body (control part) and VK observation application (Keyence Co., Ltd. VK-H1VX), load the support film with the intermediate layer measured on the x-y stage ( Let the surface with the middle layer be the upper part). Rotate the lens of the microscope unit (VK-X110 manufactured by KEYENCE Co., Ltd.), select the objective lens with a magnification of 10 times, and use the image observation mode of the VK observation application (same as VK-H1VX) to roughly adjust the focus and brightness. In the x-y stage of operation, the part to be measured on the surface of the sample is adjusted to move to the center of the screen. Replace the objective lens with a magnification of 10 times with a magnification of 100 times, and use the autofocus function of the image observation mode of the VK observation application (same as VK-H1VX) to focus on the surface of the sample. Select the simple mode of the shape measurement label of the VK observation application (same as VK-H1VX), press the measurement start button, and measure the surface shape of the sample to obtain a surface image film. Start the VK analysis application (VK-H1XA manufactured by KEYENCE Co., Ltd.), display the obtained surface image film, and perform slope correction.

In addition, the observation measurement range (horizontal) in the measurement of the surface shape of the sample is 100 μm×100 μm. Display the line roughness window. In the parameter setting area, after selecting JIS B 0601-1994, select the horizontal line with the measurement line button, and display the horizontal line at any place in the surface image. By pressing the OK button, the arithmetic mean surface roughness is obtained. The value of degree Ra. And further display horizontal lines at 4 different places in the surface image to obtain the numerical value of each arithmetic mean surface roughness Ra. Calculate the average value of the five numerical values obtained as the arithmetic mean surface roughness Ra value of each resin layer surface.

<1-5. Evaluation of resolution> Regarding the resin layer (dried) in the B-stage state (semi-cured state) formed on the flexible printed wiring substrate as described in <1-2. Formation of the resin layer> Coating film), as described in <1-4. Evaluation of Surface Roughness>, after measuring the arithmetic mean roughness Ra of each dry coating film, each of Examples, Comparative Example 1-1 and Comparative Example 1-3 The dry coating film was less than 0.1 μm. The arithmetic mean roughness Ra of the dry coating film of Comparative Example 1-2 was 0.1 or more. For each of these dried coating films, first, using an exposure device equipped with a metal halide lamp (HMW-680-GW20: manufactured by Oak Seisakusho), pattern exposure was performed at 300mJ/ ^cm2 through the negative plate to form openings with diameters of 150μm and 200μm. . The substrate having the exposed resin layer was heat-treated at 90° C. for 30 minutes.

Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30°C to develop for 1 minute, the state of pattern formation was observed, and the resolution was evaluated. The evaluation criteria are as follows.

◎: The opening pattern of 150 μm was well formed. ○: The opening pattern of 200 μm was well formed, but the opening pattern of 150 μm was slightly poor. X: Although the unexposed portion showed developability, the opening pattern of 200 μm was poorly formed (resolution is not sufficient).

＜1-6. Evaluation of heat resistance (soldering heat resistance)＞ For the evaluation board prepared as described in <1-3. Preparation of evaluation board>, apply rosin-based flux, dip it in a soldering bath set at 260°C for 20 seconds (10 seconds x 2 times), and observe the cured coating film Swelling and peeling, evaluation of heat resistance (soldering heat resistance). The evaluation criteria are as follows.

⊚: Swelling and peeling did not occur even after dipping for 10 seconds x 2 times. ◯: Swelling and peeling did not occur even after dipping for 10 seconds x 1 time, but peeling occurred after dipping twice. ×: Swelling and peeling occurred after dipping for 10 seconds × once.

＜1-7. Evaluation of Gold Plating Resistance (Chemical Resistance)＞ Evaluation boards were fabricated using the methods described in <1-3. Production of evaluation boards>, and evaluation was performed by the following method.

For the evaluation substrate, use the commercially available electroless nickel plating bath and electroless gold plating bath, apply nickel 5 μm, gold 0.05 μm plating at 80 ~ 90 ℃, observe the substrate and hardened coating film and evaluate the gold Plating resistance (chemical resistance). The evaluation criteria are as follows.

◯: There is no penetration between the substrate and the cured coating film. Δ: Penetration was confirmed between the substrate and the cured coating film. ×: A part of the cured coating film peeled off.

＜1-8. Flexibility (MIT test)＞ Each of the evaluation substrates prepared as described in <1-3. Preparation of evaluation substrates> was used as a test piece, and the MIT folding fatigue tester D-type (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to perform MIT on the film as paper in accordance with JIS P8115. Test to evaluate bendability. Specifically as shown in Figure 1, the test piece 1 is installed in the device, under the load state of load F (0.5kgf), the test piece 1 is placed vertically on the clamp 2, the bending angle α is 135 degrees, and the speed is 175cpm Bending is carried out, and the number of times of back and forth bending (times) is measured until it breaks. Moreover, the test environment is at 25°C and the radius of curvature is set at R=0.38mm. The evaluation benchmarks are as follows.

◎: After more than 200 times of bending, no cracks occurred in the hardened coating film at the bending position. 〇: After bending at 170 to 199°, no cracks were similarly generated. △: After bending at 150 to 169 folds, similarly, no cracks occurred. ×: Cracks occurred when the number of times of bending was 149 or less.

<1-9. Adhesion> Regarding the resin layer in the B-stage state (semi-hardened state) on each flexible printed wiring substrate forming the resin layer as described in <1-2. Formation of the resin layer>, As described in <1-4. Evaluation of Surface Roughness>, when the arithmetic mean roughness Ra of each dried coating film was measured, the dried coating films of each Example, Comparative Example 1-1, and Comparative Example 1-3 did not Up to 0.1μm. The arithmetic average roughness Ra of the dried coating film of Comparative Example 1-2 was 0.1 or more. With respect to each of these dried coating films, first, solid exposure was performed at 300 mJ/cm ² through a negative plate using an exposure device (HMW-680-GW20: manufactured by Oak Seisakusho) equipped with a metal halide lamp. Thereafter, after the PEB step was performed at 90°C for 30 minutes, development was performed for 60 seconds (30°C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution), and thermal curing was performed at 150°C for 60 minutes to produce a hardened form. Coated flexible printed wiring board (evaluation board). For each cured coating film, as described in <1-4. Evaluation of Surface Roughness>, after measuring the arithmetic mean roughness Ra of each dry coating film, each Example, Comparative Example 1-2 and Comparative Example 1- 3. The dry coating film is 0.1 μm or more and 1 μm or less. The arithmetic mean roughness Ra of the dried coating film of Comparative Example 1-1 was less than 0.1.

For the obtained evaluation board, cut it into a square of 2 cm on each side and stack 10 pieces, and then leave it at each temperature of 20, 30, 40, and 60°C for 72 hours, and then check whether it is bonded. The evaluation benchmarks are as follows.

◎: No bonding at 60°C 〇: No bonding at 40°C or lower, but slight bonding at 60°C △: Although there is no adhesion below 30°C, there is adhesion above 40°C ×: No bonding was observed at any temperature

The details of the components in Table 1 are as follows.

A-1: Polyamide imide resin-containing solution produced by [Synthesis Example 1] of the above ((A) Synthesis of alkali-soluble polyamide imide resin) A-2: Polyamideimide resin-containing solution produced by [Synthesis Example 2] of the above ((A) Synthesis of alkali-soluble polyamideimide resin) A-3: Polyamideimide resin-containing solution produced by [Synthesis Example 3] of the above ((A) Synthesis of alkali-soluble polyamideimide resin) PI-1: Alkali-soluble polyimide resin solution produced by [Synthesis Example 4] of the above ((E) Synthesis of alkali-soluble polyimide resin) P7-532: Polyurethane acrylate, acid value 47 mgKOH/g (manufactured by Kyoeisha Chemical Co., Ltd.) IRGACURE OXE02: Oxime-based photopolymerization initiator (manufactured by BASF Corporation) CAB-553-0.4: Cellulose acetate derivative, number average molecular weight 20,000, 20wt% DPM solution (manufactured by Eastman Chemical Company) (the parts in Table 1 represent the mass parts of the solid content of the 20wt% DPM solution) CAB-504-0.2: Cellulose acetate derivative, number average molecular weight 15,000, 20wt% DPM solution (manufactured by Eastman Chemical Company) (the parts in Table 1 represent the mass parts of the solid content of the 20wt% DPM solution) JER828: Bisphenol A epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Co., Ltd.) B-30: barium sulfate (manufactured by Sakai Chemical Industry Co., Ltd.)

As shown in Table 1, it can be seen from the comparison between the examples and the comparative examples that it is alkali-developable, and is formed of a cured resin composition with a thickness of 2 to 100 μm formed by exposure and heat treatment. When the dry coating film has an arithmetic mean roughness Ra of less than 0.1 μm, and the dried coating film has an arithmetic mean roughness Ra of the cured film after thermal curing of 0.1 μm or more and 1 μm or less, the formed resin The layer (dried coating film) is excellent in resolution, and the cured coating film (cured product) after thermosetting is excellent in heat resistance, gold plating resistance, and flexibility, and it is also confirmed that the adhesion after high-temperature storage is small.

Again, by the contrast of embodiment 1-1, 1-2, 1-4, 1-9～1-11 and embodiment 1-3, 1-5～1-8, 1-12, it can be known that drying When the film thickness of the coating film is set at 3 μm to 80 μm, and the arithmetic mean roughness Ra of the dry coating film is set at less than 0.05 μm, the arithmetic calculation of the cured film after thermal curing relative to the arithmetic mean roughness Ra of the dry coating film When the ratio of average roughness Ra (arithmetic average roughness Ra of cured film after thermal curing/arithmetic average roughness Ra of dry coating film) is 6 or more, the resolution of the formed resin layer (dry coating film) is greatly improved It is improved, and the adhesion of the cured coating film (cured product) after thermal curing is further reduced after high temperature storage.

[Example of the curable resin composition of the second aspect of the present invention] <2-1. Preparation of Curable Resin Compositions of Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-2> According to the component composition shown in the following Table 2, the materials of the hardening resin composition of Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-2 were added, and this was pre-mixed with a mixer, and then The 3-roll mixer performs kneading to adjust each curable resin composition to form a resin layer. In addition, unless otherwise specified, the values in Table 2 are parts by mass of solid content.

For each curable resin composition mentioned above, a resin layer (dry coating film) in the B-stage state (semi-cured state) of each curable resin composition was formed as shown below, and developability (alkali solubility) was evaluated. And as described later, a flexible printed wiring board having a cured product of the resin layer was formed, and heat resistance (soldering heat resistance), gold plating resistance (chemical resistance), flexibility, and adhesion were evaluated. The results are shown in Table 2.

＜2-2. Formation of resin layer＞ A flexible printed wiring base material with a circuit having a copper thickness of 18 μm was prepared, and pretreatment was performed using CZ-8100 from MEC Corporation. Thereafter, each of the curable resin compositions obtained in Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-2 was applied to the pretreated flexible printed wiring substrate and dried. The film thickness was 30 μm. Thereafter, it was dried at 90° C. for 30 minutes in a hot air circulation drying oven to form a resin layer (dried coating film) in a B-stage state (semi-cured state).

<2-3. Preparation of evaluation board> For the resin layer (dry coating film) in the B-stage state (semi-cured state) on each flexible printed wiring substrate with the resin layer formed as above, first mount it using a metal halide lamp The exposure device (HMW-680-GW20: manufactured by Oak Seisakusho Co., Ltd.) was subjected to pattern exposure at 300 mJ/cm ² through the negative tool until an opening with a diameter of 200 μm was formed. Thereafter, after the PEB step was performed at 90°C for 30 minutes, development was performed for 60 seconds (30°C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution), and after thermal curing at 150°C for 60 minutes, the formed A flexible printed wiring board (evaluation board) with a cured resin layer (cured coating film).

<2-4. Evaluation of developability (alkali solubility)> For the B-stage state (semi-hardened state) formed on the flexible printed wiring substrate as described in <2-2. Formation of resin layer> The resin layer (dried coating film) was first pattern-exposed at 300mJ/ ^cm2 through a negative mask using an exposure device equipped with a metal halide lamp (HMW-680-GW20: manufactured by Oak Seisakusho) to form an opening with a diameter of 200μm. The substrate with the exposed resin layer was heat-treated at 90° C. for 30 minutes.

Thereafter, the substrate was immersed in a 1% by mass sodium carbonate aqueous solution at 30°C to develop for 1 minute, the state of pattern formation was observed, and the developability (alkali solubility) was evaluated. The evaluation criteria are as follows.

◯: The exposed portion exhibited development resistance, the unexposed portion exhibited developability, and the pattern formation was good. ×: The unexposed part showed developability, but the resolvability pattern formation was poor (resolubility was not sufficient).

＜2-5. Evaluation of heat resistance (soldering heat resistance)＞ For the evaluation board prepared as described in <2-3. Preparation of evaluation board>, apply rosin-based flux, dip it in a soldering bath set at 260°C for 20 seconds (10 seconds x 2 times), and observe the hardened coating. Swelling and peeling of the film, evaluation of heat resistance (soldering heat resistance). The evaluation criteria are as follows. ⊚: No swelling or peeling even after dipping for 10 seconds x 2 times. ◯: Even after 10 seconds of immersion once, there was no swelling and peeling, but peeling occurred in the second immersion. ×: Swelling and peeling occurred when immersion was performed for 10 seconds×1 time.

＜2-6. Evaluation of Gold Plating Resistance (Chemical Resistance)＞ Using the evaluation board produced as described in <2-3. Preparation of evaluation board>, evaluation was performed according to the following method.

For the evaluation substrate, use the commercially available electroless nickel plating bath and electroless gold plating bath, apply nickel 5μm and gold 0.05μm plating at 80-90°C, observe and evaluate the substrate and hardened coating film Gold plating resistance (chemical resistance). The evaluation criteria are as follows.

◯: There is no penetration between the substrate and the cured coating film. Δ: Permeation was confirmed between the substrate and the cured coating film. x: Part of the cured coating film peeled off.

＜2-7. Flexibility (MIT test)＞ Each of the evaluation substrates prepared as described in <2-3. Preparation of evaluation substrates> was used as a test piece, and the MIT folding fatigue tester D-type (manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to conduct MIT with a film as paper in accordance with JIS P8115. Test to evaluate bendability. Specifically as shown in Figure 1, install the test piece 1 on the device, under the state of load F (0.5kgf), place the test piece 1 vertically on the clamp 2, the bending angle α is 135 degrees, and the speed is set at It was bent at 175 cpm, and the number of times of back-and-forth bending (times) was measured until it broke. Moreover, the test environment is at 25°C and the radius of curvature is set at R=0.38mm. The evaluation benchmarks are as follows.

◎: After more than 200 times of bending, no cracks occurred in the hardened coating film at the bending position. 〇: After bending at 170 to 199°, no cracks were similarly generated. △: After bending at 150 to 169 folds, similarly, no cracks occurred. ×: Cracks occurred when the number of times of bending was 149 or less.

<2-8. Adhesion> Regarding the resin layer in the B-stage state (semi-hardened state) on each flexible printed wiring substrate on which the resin layer was formed as described in <2-2. Formation of the resin layer ( Dry the coating film), and first use an exposure device equipped with a metal halide lamp (HMW-680-GW20: manufactured by Oak Seisakusho) to perform solid exposure at 300 mJ/cm ² through the negative tool. Thereafter, after performing the PEB step at 90°C for 30 minutes, developing (30°C, 0.2MPa, 1% by mass Na ₂ CO ₃ aqueous solution) for 60 seconds, and by performing thermal curing at 150°C for 60 minutes, the formed A flexible printed wiring board (evaluation board) with a cured resin layer (cured coating film).

For the obtained evaluation board, cut it into a square of 2 cm on each side and stack 10 pieces, and then leave it at each temperature of 20, 30, 40, and 60°C for 72 hours, and then check whether it is bonded. The evaluation benchmarks are as follows.

◎: No bonding at 60°C 〇: No bonding at 40°C or lower, but slight bonding at 60°C △: Although there is no adhesion below 30°C, there is adhesion above 40°C ×: No bonding was observed at any temperature

表2-1中之成分的詳細如以下所示。

The details of the components in Table 2-1 are as follows.

PI-1: Alkali-soluble polyimide resin solution produced in [Synthesis Example 4] of the above ((E) Synthesis of alkali-soluble polyimide resin) A-3: Polyamideimide resin-containing solution produced in [Synthesis Example 3] of the above ((A) Synthesis of alkali-soluble polyamideimide resin) A-1: Polyamideimide resin-containing solution produced in [Synthesis Example 1] of the above ((A) Synthesis of alkali-soluble polyamideimide resin) P7-532: polyurethane acrylate, acid value 47 mgKOH/g (manufactured by Kyoeisha Chemical Co., Ltd.) IRGACURE OXE02: Oxime-based photobase generator (manufactured by BASF Corporation) CAB-553-0.4: Cellulose acetate derivative, number average molecular weight 20,000, 20wt% DPM solution (manufactured by Eastman Chemical Company) (the parts in Table 2 represent the mass parts of the solid content of the 20wt% DPM solution) CAB-504-0.2: Cellulose acetate derivative, number average molecular weight 15,000, 20wt% DPM solution (made by Eastman Chemical Co.) CA-1: CAB-553-0.4 denatured with methyl methacrylate produced in [Synthesis Example 5] of ((D) Synthesis of Cellulose Derivatives), number average molecular weight 24,000, 20wt% MEK solution (Table The parts in 2 represent the mass parts of the solid content of the 20wt% MEK solution) CA-2: CAB-553-0.4 denatured with glycidyl methacrylate produced in [Synthesis Example 6] of ((D) Synthesis of Cellulose Derivatives), number average molecular weight 25,000, 20wt% MEK solution (the parts in Table 2 represent the mass parts of the solid content of the 20wt% MEK solution) jER828: Bisphenol A epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

As shown in Table 2, it can be known from the comparison between the examples and the comparative examples that the curable resin composition contains (A) alkali-soluble polyamideimide resin, (C) thermosetting compound and ( B) In addition to the photobase generator, (D) cellulose derivatives are also contained, and the formed resin layer has good developability, and the cured resin layer is not only excellent in heat resistance, gold plating resistance, and flexibility, but also confirmed that Combined into small.

Also, from the comparison of Examples 2-1 to 2-2 and Examples 2-3 to 2-8, it can be seen that the ratio of the addition amount of (A) alkali-soluble polyamideimide resin to (E) When there are more alkali-soluble polyimide resins, the heat resistance can be further improved. Also, from the comparison of Example 2-3 and Examples 2-7 to 2-8, it can be further reduced by using the group containing the group represented by formula (6) as (D) cellulose derivative. In other words, it is known that the fit evaluation result is good. Also, from the comparison of Examples 2-3 and Examples 2-6, it can be seen that as (A) polyamide imide resin with alkali solubility, use has the structure shown in formula (1) and formula (2) The polyamideimide resin with the structure shown can also improve flexibility and adhesion.

[ Fig. 1 ] An explanatory diagram of an MIT test performed on an evaluation substrate produced in an example as a test piece.

Claims (14)

A curable resin composition, which is alkali-developable and forms a cured film by exposure and heat treatment, characterized in that a dry coating with a thickness of 2 to 100 μm is formed from the curable resin composition In the case of a film, the dry coating film has an arithmetic mean roughness Ra of less than 0.1 μm, and the dried coating film has an arithmetic mean roughness Ra of the cured coating film after thermal curing of 0.1 μm or more and 1 μm or less. The curable resin composition according to claim 1, wherein in the case of forming a dry coating film having a thickness of 2 to 100 μm from the curable resin composition, the arithmetic mean roughness Ra of the dry coating film is less than 0.05 μm, and the aforementioned The arithmetic mean roughness Ra of the cured coating film after thermal curing of the dry coating film is 0.1 μm or more and 0.5 μm or less. The curable resin composition according to claim 1 or 2, which contains (A) alkali-soluble polyamide imide resin, (B) photobase generator, (C) thermosetting compound and (D) fiber prime derivatives. The curable resin composition according to claim 1, wherein the aforementioned (C) thermosetting compound is an epoxy resin. A laminated structure in which at least one side of a resin layer formed of the curable resin composition according to claim 1 is supported or protected by a film. A cured product characterized by the curable resin composition as claimed in claim 1, or the resin layer as claimed in claim 5. An electronic component characterized by having an insulating film made of the cured product according to claim 6. A curable resin composition is characterized by containing (A) alkali-soluble polyimide resin, (B) photobase generator, (C) thermosetting compound and (D) cellulose derivative. The curable resin composition according to claim 8, wherein the (A) alkali-soluble polyamideimide resin has a carboxyl group. The curable resin composition according to claim 9, wherein (A) the alkali-soluble polyamideimide resin has a carboxyl group and a phenolic hydroxyl group. The curable resin composition according to claim 8, which further contains (E) an alkali-soluble polyimide resin. The curable resin composition according to claim 8, wherein the aforementioned (C) thermosetting compound is an epoxy resin. A cured product obtained from the curable resin composition according to claim 8. An electronic component characterized by having an insulating film made of the cured product according to claim 13.

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