TW202342577A - 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 compositions, laminated structures, cured products and electronic parts

The present invention relates to a laminated structure of a resin layer formed of the curable resin composition, a cured product thereof, and an electronic component having an insulating film made of the cured product. In particular, it relates to alkali-developable and by-product A curable resin composition formed by exposure and heat treatment to form a cured film, a laminated structure of a resin layer formed of the curable resin composition, a cured product thereof, and an electronic device having an insulating film formed of the cured product Component.

In the past, a non-photosensitive resin structure in which a thermosetting adhesive was applied to a thin film such as polyimide was used as a protective film for flexible printed wiring boards. As a method of patterning a non-photosensitive resin structure to form a flexible printed wiring board, in the past, there has been a method of opening holes by punching and then thermally pressing the flexible printed wiring board. method. Alternatively, there is also a method in which a solvent-soluble thermosetting resin composition is directly printed on a flexible printed wiring board and then thermally cured to form a pattern. In particular, a polyimide film is used as a material that is flexible, has excellent heat resistance, mechanical properties, and electrical properties, and is a preferred material for a flexible printed wiring board (see, for example, Patent Document 1). However, in the above-mentioned conventional method, the shape of the edge portion of the pattern may be broken due to resin seepage during coating or hot pressing. It becomes difficult to form the fine patterns required for lithography. [Prior technical literature] [Patent Document]

[Patent Document 1] WO2012/133665

[Problem solved by the invention]

On the other hand, it is also considered that a photosensitive solder resist, which is known as a permanent protective film for circuits that can be finely processed, is used as a cover layer of a flexible printed wiring board. Since the photosensitive solder resist in flexible printed wiring boards can impart flexibility, it is necessary to reduce the cross-linking density. Since flexible substrates are thin and easily bent, many of them must be stacked and fixed before being stored or transported. The storage environment is further elevated to a high temperature due to the transportation environment. When a photosensitive soldering resist is used as a cover layer, the area to protect the flexible printed wiring board becomes wider. Therefore, by lowering the cross-linking density, the area on the substrate is reduced. The formed coating films sometimes adhere to each other.

In addition, in recent years, in fields using rigid boards, there have been increasing demands for thinner films. 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 adhering to each other will also occur.

To solve this problem, when the surface roughness of the coating film is increased, the surface area to be contacted will become smaller and adhesion will not occur. However, if a coating film with a large surface roughness is patterned by photolithography, halation will occur 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 resolution of the dried coating film, good flexibility of the resulting cured product, and has low adhesion characteristics 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 products are stacked and stored. , a hardening resin composition with low adhesion properties. [Means to solve the problem]

In order to achieve the above-mentioned first object, the present inventors conducted detailed examinations. As a result, the surface roughness (arithmetic mean roughness) can be maintained small when the coating film is dried, and the curable resin composition can increase the surface roughness (arithmetic mean roughness) after thermal curing. , to achieve the high resolution of a dry coating film, the flexibility and low adhesion of a thermosetting film, and complete the present invention. In addition, in this specification, the term "resolution" refers to the ability to express the details of an image obtained by alkali development after exposing a resin layer made of the curable resin composition of the present invention.

That is, the first object of the present invention is to provide a curable resin composition that can be developed by alkali and form a cured film by exposure and heat treatment. It has been found that the curable resin composition can form a cured film with a thickness of 2 to 100 μm. When drying the coating film, the arithmetic mean roughness Ra of the dry coating film is less than 0.1 μm, and the arithmetic mean roughness Ra of the cured film after thermal curing of the dry coating film is 0.1 μm or more and 1 μm or less as a characteristic hardenability. This can be achieved with a resin composition (hereinafter also referred to as the curable resin composition of the first aspect of the present invention).

For the purposes of this specification, the so-called resolution refers to the ability to express the details of an image obtained when a resin layer made of the curable resin composition of the first aspect of the present invention is subjected to pattern exposure and then subjected to alkali development.

Furthermore, the curable resin composition according to the first aspect of the present invention is such that when a dry coating film with 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 mean roughness Ra of the cured film after thermal curing of the dry coating film is preferably 0.1 μm or more and 0.5 μm or less.

Furthermore, one containing (A) an alkali-soluble polyamideimide resin, (B) a photobase generator, (C) a thermosetting compound, and (D) a cellulose derivative is preferred.

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

Therefore, the first object of the present invention is to provide a laminate structure in which 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 curable resin composition of the present invention Alternatively, a cured product of the resin layer of the laminated structure of the present invention and an electronic component having an insulating film made of the cured product of the present invention can also be achieved.

In addition, the present inventors conducted detailed examinations in order to achieve the above-mentioned second object. As a result, it was discovered that when a cellulose derivative is added to a curable resin composition and a predetermined amount of alkali-soluble polyimide resin is blended, the resulting cured products become less adherent to each other, and the present invention was completed.

That is, it was found that the aforementioned second object of the present invention can be achieved by containing (A) an alkali-soluble polyamide imine resin, (B) a photobase generator, (C) a 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).

Furthermore, (A) the alkali-soluble polyamide imine resin preferably has a carboxyl group, and (A) the alkali-soluble polyamide imine resin has a carboxyl group and a phenolic hydroxyl group.

Furthermore, it is preferable that the curable resin composition according to 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. [Effects of the 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 obtained cured product after thermal curing is also good, and the cured product is stacked and It also has low adhesion properties when stored in high temperature environments. Furthermore, the dry coating film of the curable composition according to the second aspect of the present invention has good developability, and the cured product obtained from the curable composition according to the second aspect of the present invention has good heat resistance and flexibility. It also has low-contact properties when stacked and stored.

[Types of carrying out the invention] <The curable resin composition according to the first aspect of the present invention>

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

The curable resin composition according to the first aspect of the present invention is alkali-developable and is intended to form a cured film by exposure and heat treatment. The component has a functional group containing alkali solubility (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, (B) the photobase generator can change the molecular structure by irradiation with light such as ultraviolet light or visible light, or can be used as an alkali-soluble compound and (C) the thermosetting compound by cleavage of the molecules. The catalyst for the reaction performs its function.

Examples of the alkali-soluble compound include a compound having a phenolic hydroxyl group, a compound having a carboxyl group, and a compound having a phenolic hydroxyl group and a carboxyl group. A preferred alkali-soluble compound is the alkali-soluble polyamide imine resin (A) described below. Among them, as the alkali-soluble polyamide imine resin (A), a polyamide imine resin having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) can also be 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 improved resolution, it is preferable that when a dry coating film is formed of 3 to 80 μm, the arithmetic mean roughness of the dry coating film is The thickness Ra is less than 0.1 μm, preferably less than 0.05 μm, and the arithmetic mean roughness Ra of the cured film after thermal hardening of the dry coating film is 0.1 μm or more and 1 μm or less, preferably 0.1 μm or more and 0.5 μm or less.

When the arithmetic mean roughness Ra of the dry coating film is less than 0.1 μm, random reflection of light irradiating the coating film during exposure is suppressed and resolution becomes good. In addition, by setting the arithmetic mean roughness Ra of the cured film to 0.1 μm or more and 1 μm or less after thermal curing, small unevenness will be generated on the cured film. Due to these irregularities, the contact area between the stacked and arranged cured films becomes smaller, resulting in reduced adhesion.

The unevenness of the dry coating film in the state of the dry coating film before thermal hardening is small, and the phenomenon that the unevenness on the cured film becomes larger after thermal hardening is considered to be because of the curable resin composition of the present invention. It is produced by containing a polymer component having different compatibility with the above-mentioned (C) thermosetting compound or alkali-soluble compound. That is, it is presumed that the polymer component dispersed in the dry coating film before thermal curing moves to the film surface during the thermal curing reaction.

As this polymer component, it is preferable to add (D) cellulose derivative.

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

<Cureable resin composition according to the second aspect of the present invention> The curable resin composition according to the second aspect of the present invention contains (A) an alkali-soluble polyamide imine resin, (B) a photobase generator, (C) a thermosetting compound, and (D) fibers. phytozoin derivatives.

The curable resin composition according to 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 polyamide imine resin] (A) The alkali-soluble polyamide imine resin is a preferred example of the above-mentioned alkali-soluble photocurable compound. (A) The alkali-soluble polyamide imine resin contains an alkali-soluble group (one or more types of phenolic hydroxyl group and carboxyl group). The curable resin composition according to the first aspect of the present invention preferably contains (A) an alkali-soluble polyamide imine resin. The curable resin composition according to the second aspect of the present invention preferably contains (A) an alkali. Soluble polyamide imine resin.

Examples of such alkali-soluble polyamide imide resins include resins obtained by reacting a carboxylic anhydride component and an amine component to obtain an imide compound, and then reacting the obtained imide compound 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. Furthermore, the imidization may be carried out by thermal imidization, chemical imidization, or a combination of these.

Examples of the carboxylic anhydride component include tetracarboxylic anhydride and tricarboxylic anhydride. However, the carboxylic acid anhydride component is not limited to these acid 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 acid anhydride components can 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 a carboxyl group, diamines having a phenolic hydroxyl group, and the like can be used. The amine component is not limited to these amines, and an amine capable of introducing at least one functional group of a phenolic hydroxyl group or a carboxyl group must be used. Moreover, these amine components can 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 commonly used diisocyanates can be used. It is not limited only to these isocyanates. Moreover, these isocyanate components can be used individually or in combination.

(A) When an alkali-soluble polyamide imine resin is contained in the curable resin composition of the present invention, the alkali solubility (developerability) of the polyamide imine resin is compared with that of the polyamide imine resin containing the polyamide imine resin. From the viewpoint of maintaining a good balance of mechanical properties and other properties of the cured resin composition of the amine imine resin, the acid value (acid value of the solid content) is preferably 30 mgKOH/g or more, and 30 mgKOH/g or less. 150 mgKOH/g is preferred, and 50 mgKOH/g to 120 mgKOH/g is particularly preferred. Specifically, by setting the acid value to 30 mgKOH/g or more, the alkali solubility, that is, the developability becomes good, and the cross-linking density with the thermosetting component after light irradiation becomes high, so that sufficient development contrast can be obtained. . In addition, by setting the acid value to 150 mgKOH/g or less, so-called overheating in the PEB (POST EXPOSURE BAKE) step after light irradiation described below can be suppressed, thereby increasing the process width.

Furthermore, when the molecular weight of (A) the alkali-soluble polyamideimide resin is taken into account in terms of developability and cured coating film characteristics, the mass average molecular weight is preferably 20,000 or less, more preferably 1,000 to 17,000, and 2,000. ~15,000 is better. If the molecular weight is 20,000 or less, the alkali solubility of the unexposed portion will increase, thereby improving the developability. On the other hand, if the molecular weight is 1,000 or more, sufficient development resistance and cured physical properties can be obtained for the exposed part after the exposure and PEB steps.

(A) When an alkali-soluble polyamide imine resin is contained in the curable resin composition of the present invention, one having a structure represented by the following general formula (1) and the following general formula (2) is particularly used. It is preferable from the viewpoint of further improving the developability and improving the flexibility and adhesion of the polyamide imine resin having a structure. Moreover, it is not only the case where the structure represented by general formula (1) and the structure represented by the following general formula (2) are contained in one molecule of (A) alkali-soluble polyamide imine resin, if it is contained in (A) ) alkali-soluble polyamide imine resin can be used.

(In the general formula ( ₁ ), group, in general formula (2), X ₂ is the residue of aromatic diamine (b) having a carboxyl group (also referred to as "carboxy group-containing diamine (b)" in this specification). For general formula (1) and (2), Y is each independently cyclohexane or aromatic ring)

By containing the structure represented by the above general formula (1) and the structure represented by the above general formula (2), even when a mild alkali solution such as 1.0 mass% sodium carbonate aqueous solution is used, it can become soluble in alkali solubility. Excellent polyamideimide resin. Furthermore, the cured product of the curable resin composition containing the polyamide imine 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) derived from an aliphatic diamine derived from a dimer acid is polymerized with unsaturated fatty acids such as oleic acid and linoleic acid to form a dimer acid. After this is reduced, the amine group is Obtained after transformation. As such aliphatic diamine, for example, commercially available products such as PRIAMINE 1073, 1074, and 1075 (trade name manufactured by Croda Japan), which are diamines having a carbon number of 36, can be used. The dimer diamine (a) is preferably derived from a dimer acid having 28 to 44 carbon atoms, and is more preferably derived from a dimer acid having 32 to 40 carbon atoms.

Specific examples of the carboxyl group-containing diamine (b) include 3,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, and 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 a plurality of types of compounds. From the viewpoint of raw material availability, the carboxyl group-containing diamine (b) is preferably one containing 3,5-diaminobenzoic acid or 5,5'-methylenebis(anthralaminobenzoic 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 polyamide imine resin is not limited. From the viewpoint of a good balance between the alkali solubility of the polyamide imine resin and the mechanical properties and other properties of the cured product of the curable resin composition containing the polyamide imine resin, dimer diamine The content (unit: mass %) of (a) is preferably 20 to 60 mass %, and 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 imine resin. , meaning the ratio relative to the mass of the polyamide imine resin produced. Among them, "the mass of the polyamide imine resin produced" means that the amount of all raw materials to be produced for the polyamide imine resin is subtracted from the amount of water (H ₂ O produced during the imidization). ) and the value of the theoretical amount of carbonic acid gas (CO ₂ ) produced during amidation.

From the viewpoint of improving the alkali solubility of the polyamideimide resin, the part represented by Y in the above general formula (1) and the above general formula (2) is preferably one having a cyclohexane ring. From the viewpoint of a good balance between the alkali solubility of the polyamide imine resin and the mechanical properties and other properties of the cured product of the resin composition containing the polyamide imine resin, the portion indicated by Y above The relationship between the amounts of aromatic rings and cyclohexane rings is: 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 90/10~98/2 is better.

The method for producing the above-mentioned (A) alkali-soluble polyamide imide resin is not particularly limited, and can be produced through a amide imidization step and a amide imidization step using a known and commonly used 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 dimer diamine (a) is preferably an amount such that the content of dimer diamine (a) is 20 to 60% by mass, and the content of dimer diamine (a) is preferably 30% by mass. An amount of ~50% by mass is preferred. The content of the dimer diamine (a) is defined as described above.

If necessary, the dimer diamine (a) and the carboxyl group-containing diamine (b) can be used together with other diamines. Specific examples of other diamines include 2,2-bis[4-(4-aminophenoxy)phenyl]propane and bis[4-(3-aminophenoxy)phenyl]terine , bis[4-(4-aminophenoxy)phenyl]terine, 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]one, 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)diphenyl terine, (4,4'-diamine Amino)benzophenone, (3,3'-diamino)benzophenone, (4,4'-diamino)diphenylmethane, (4,4'-diamino)diphenyl ether, (3,3'-diamino)diphenyl ether and other aromatic diamines, examples of which include hexamethylenediamine, octamethylenediamine, decamethylenediamine, dodecylenediamine Methyldiamine, octadecarylamine, 4,4'-methylenebis(cyclohexylamine), isophoronediamine, 1,4-cyclohexanediamine, norbornenediamine and other aliphatic diamines.

From the viewpoint of improving the alkali solubility of the polyamide imine resin, in the imidization step, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) is used. Better. The molar ratio of the usage amount of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) to the usage amount of trimellitic anhydride (d) is preferably 85/15 to 100/0. The one between 90/10 and 99/1 is better, and the one between 90/10 and 98/2 is even better.

The amount of the diamine compound (specifically, the dimer diamine (a), the carboxyl group-containing diamine (b), and other diamines used if necessary) used to obtain the imide compound is different from the amount of the acid anhydride (specifically, The relationship indicating the amount of one or two selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (c) and trimellitic anhydride (d) is not limited. The amount of the acid anhydride used is preferably such that the molar ratio relative to the amount of the diamine compound is 2.0 or more and 2.4 or less, and preferably such that the molar ratio is 2.0 or more and 2.2 or less.

In the amide imidization step, a diisocyanate compound is reacted with the amide imide obtained in the above amide imidization step to obtain a polyamide amide containing a substance having a structure represented by the general formula (3) described below. imine resin.

The specific type of diisocyanate compound is not particularly limited. The diisocyanate compound may be composed of one type of compound or a plurality of types of compounds.

Specific examples of the diisocyanate compound 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-terdipolymer; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate Aliphatic diisocyanates such as isocyanate, isophorone diisocyanate, norbornene diisocyanate, etc. From the viewpoint of improving both the alkali solubility of the polyamide imine resin and the light transmittance of the polyamide imine resin (A) with alkali solubility, the diisocyanate compound contains an aliphatic isocyanate. Preferably, the diisocyanate compound contains an aliphatic isocyanate.

The amount of diisocyanate compound used in the amide imidization step is not limited. From the viewpoint of imparting moderate alkali solubility to the polyamide imine resin, the amount of the diisocyanate compound used is 0.3 as a molar ratio to the amount of the diamine compound used to obtain the imine compound. The one with the above 1.0 and below is better, the one with 0.4 and below 0.95 is better, the one with 0.50 and below 0.90 is particularly good.

The polyamide imine resin produced in this way contains the following general formula (3) (In the above general formula (3), X is each independently a diamine residue (residue of a diamine compound), Y is each independently an aromatic ring or a cyclohexane ring, and Z is a residue of a diisocyanate compound. n is natural Number) of the substance shown in the structure.

The optimal blending amount of (A) the alkali-soluble polyamide imine resin and (E) the alkali-soluble polyimide resin as an optional component described below is based on 100 parts by mass of the curable resin composition of the present invention. , for example, 10 parts by mass or more and 85 parts by mass or less, preferably 15 parts by mass or more and 80 parts by mass or less, particularly preferably 20 parts by mass or more and 75 parts by mass or less.

[(B) Photobase generator] The curable resin composition according to the first aspect of the present invention is composed of (A) an alkali-soluble polyamide imine resin (and (E) an alkali-soluble polyimide resin as an optional component described below), The one between (C) the thermosetting compound and (B) the photobase generator is preferred, and the curable resin composition according to the second aspect of the present invention contains the (B) photobase generator. (B) The photobase generator changes the molecular structure by irradiation with light such as ultraviolet or visible light, or cleaves the molecules to generate contact as an addition reaction between a polyimide resin having a carboxyl group and a thermosetting component. A compound of more than one alkaline substance that can exert its function as a mediator.

Examples of the basic substance include secondary amines and tertiary amines.

Examples of the photobase generator include α-aminoacetophenone compounds, oxime ester compounds, compounds having a acyloxyimino group, an N-methylated aromatic amine group, and an N-methylated aromatic amine. Compounds with substituents such as nitrobenzylcarbamate group and alkoxybenzylcarbamate group. Among them, oxime ester compounds and α-aminoacetophenone compounds are also preferred. As the α-aminoacetophenone compound, one having two or more nitrogen atoms is particularly preferred.

As other photobase generators, WPBG-018 (trade name: 9-anthrylmethyl N,N'-diethylcarbamate; 9-anthracenylmethyl 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; imidazole ethylcarboxylate), etc. (the above are manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). The α-aminoacetophenone compound has a benzoin ether bond in the molecule. When exposed to light, it will cause cracking in the molecule and generate an alkaline substance (amine) that acts as a hardening catalyst.

As a specific example of the α-aminoacetophenone compound, (4-morpholinobenzyl)-1-benzyl-1-dimethylaminopropane (Omnirad (Omnirad) 369, trade name , IGM Resins Co., Ltd.) or 4-(methylthiobenzyl)-1-methyl-1-morpholinoethane (Omnirad 907, trade name, IGM Resins Co., Ltd.), 2-(dimethyl methylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (Omnirad 379, trade name, IGM Resins (manufactured by) or other commercially available compounds or solutions thereof.

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, R ₁ represents a hydrogen atom, an unsubstituted or phenyl group substituted by an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom, an unsubstituted or unsubstituted phenyl group having 1 to 20 carbon atoms substituted by one or more hydroxyl groups. an alkyl group, an alkyl group interrupted by one or more oxygen atoms, a cycloalkyl group having 5 to 8 carbon atoms that is unsubstituted or substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group, or a cycloalkyl group having 5 to 8 carbon atoms that is unsubstituted or substituted with a carbon An alkyl group or benzyl group having 2 to 20 carbon atoms substituted by an alkyl group with 1 to 6 carbon atoms or a phenyl group, and R ₂ represents unsubstituted or substituted by an alkyl group with 1 to 6 carbon atoms, a phenyl group or a halogen atom. Substituted phenyl group, unsubstituted or alkyl group having 1 to 20 carbon atoms substituted by one or more hydroxyl groups, the alkyl group interrupted by one or more oxygen atoms, unsubstituted or alkyl group having 1 to 6 carbon atoms Or a cycloalkyl group with 5 to 8 carbon atoms substituted by a phenyl group, an alkyl group with 2 to 20 carbon atoms or a benzyl group that is unsubstituted or substituted with an alkyl group with 1 to 6 carbon atoms or a phenyl group.) Examples of commercially available oxime ester photobase generators include IRGACURE OXE01 and IRGACURE OXE02 manufactured by BASF Japan, N-1919 and NCI-831 manufactured by ADEKA, etc. In addition, compounds having two oxime ester groups in the molecule as described in Patent No. 4344400 can also be used.

Others include Japanese Patent Application Publication No. 2004-359639, Japanese Patent Application Publication No. 2005-097141, Japanese Patent Application Publication No. 2005-220097, Japanese Patent Application Publication No. 2006-160634, Japanese Patent Application Publication No. 2008-094770, and Japanese Patent Application Publication No. 2008-094770. Carbazole oxime ester compounds described in Japanese Patent Application Publication No. 2008-509967, Japanese Patent Application Publication No. 2009-040762, and Japanese Patent Application Publication No. 2011-80036, etc.

Such a photobase generator may be used individually by 1 type, and may be used in combination of 2 or more types. The amount of the (B) photobase generator in the curable resin composition of the present invention is based on 100 parts by mass of the (A) alkali-soluble polyamide imine resin, or the amount of the alkali-soluble polyamide imine resin. In the case of the imide resin, for example, 0.1 part by mass or more and 40 parts by mass relative to 100 parts by mass of the total amount of (A) the alkali-soluble polyamide imine resin and the alkali-soluble polyimide resin. parts or less, preferably not less than 0.2 parts by mass and not more than 20 parts by mass.

When the amount is 0.1 parts by mass or more, good development resistance contrast between the light irradiated part and the non-irradiated part can be obtained. In addition, when the content is 40 parts by mass or less, the properties of the cured product can be improved.

[(C) Thermosetting compound] The curable resin composition according to 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) As the thermosetting compound, epoxy resin, urethane resin, polyester resin, hydroxyl group, amine group or carboxyl group-containing polyurethane, polyester, polycarbonate, polyol, Commonly known thermosetting resins such as phenoxy resin, acrylic copolymer resin, vinyl resin, oxazine resin, and cyanate ester resin.

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

Specific examples of the epoxy resin include jER828 manufactured by Mitsubishi Chemical Corporation, EHPE3150 manufactured by Daicel Chemical Industries, Ltd., EPICLON840 manufactured by DIC Corporation, EpotohtoYD-011 manufactured by Nippon Steel Chemical & Materials Co., Ltd., and Dow/Chemicals. Bisphenol A-type epoxy resins such as D.E.R.317 manufactured by Sumitomo Chemical Company, SumiepoxyESA-011 manufactured by Sumitomo Chemical Company (all are trade names); jERYL903 manufactured by Mitsubishi Chemical Company, EPICLON152 manufactured by DIC Company, and Nippon Steel Chemical & Materials Company Brominated epoxy resins such as EpotohtoYDB-400, D.E.R.542 made by Dow/Chemicals, SumiepoxyESB-400 made by Sumitomo Chemicals (all are trade names); jER152 made by Mitsubishi Chemicals, D.E.N.431 made by Dow/Chemicals , EPICLON N-730 manufactured by DIC Corporation, EpotohtoYDCN-701 manufactured by Nippon Chemical & Materials Corporation, EPPN-201 manufactured by Nippon Chemical Corporation, SumiepoxyESCN-195X manufactured by Sumitomo Chemical Corporation, etc. (all are trade names). Type epoxy resin; bisphenol F-type epoxy such as EPICLON830 made by DIC, jER807 made by Mitsubishi Chemical Corporation, Epotohto YDF-170, YDF-175, YDF-2004 made by Nippon Steel Chemical & Materials Co., Ltd. (all are 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 Company, Epotohto YH-434 manufactured by Nippon Steel Chemical & Materials Co., Ltd., and Sumitomo Chemical Co., Ltd. Glycidylamine type epoxy resins such as SumiepoxyELM-120 (all are trade names); hydantoin type epoxy resins; alicyclic epoxy resins such as CELLOXIDE2021 (all are trade names) manufactured by Daicel Chemical Industries, Ltd. Epoxy resin; trihydroxyphenylmethane type epoxy resin such as EPPN-501 manufactured by Nippon Kayaku Corporation (all are trade names); YL-6056, YX-4000, YL-6121 manufactured by Mitsubishi Chemical Corporation (all are Bisxylenol-type or bisphenol-type epoxy resins or mixtures thereof such as EBPS-200 manufactured by Nippon Kayaku Corporation, EPX-30 manufactured by ADEKA, 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 Company; heterocyclic epoxy resin such as TEPIC manufactured by Nissan Chemical Company (all trade names); Phenyl novolak-type epoxy resin; naphthyl-containing epoxy resins such as ESN-190 made by Nippon Steel Chemical & Materials Co., Ltd. and HP-4032 made by DIC Co., Ltd.; rings with dicyclopentadiene skeleton such as HP-7200 made by DIC Co., Ltd. Oxygen resin, etc.

(C) The thermosetting compound may be compounded in any amount. However, when (A) alkali-soluble polyamide imine resin is contained, the equivalent ratio (alkali-soluble polyamide imine resin) to alkali-soluble polyimide resin It is better to mix the base (thermosetting group such as epoxy group) in 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 having different compatibility with the above-mentioned (C) thermosetting compound or alkali-soluble photocurable compound. A derivative is preferred, and the curable resin composition according to 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 preferably soluble in an organic solvent and has a high glass transition temperature (Tg). Examples of (D) cellulose derivatives include cellulose ethers, carboxymethylcellulose, cellulose esters, etc., which will be described later.

Examples of cellulose ethers include ethyl cellulose, hydroxyalkyl cellulose, and the like. Examples of commercial products of ethyl cellulose include Etocell (registered trademark) 4, Etocell 7, Etocell 10, Etocell 14, Etocell 20, Etocell 45, Etocell70, Etocell100, Etocell200, Etocell300 (all are trade names of Dow/Chemicals). Examples of commercial products of hydroxyalkyl cellulose include MetrosSM, Metros60SH, Metros65SH, Metros90SH, MetrosSEB, and MetrosSNB (all are Shin-Etsu Chemicals). Trade name of industrial (stock) system), etc.

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

A more preferred cellulose derivative is a cellulose ester in which the hydroxyl group of cellulose is esterified with an organic acid. Specific examples include the following formula (5) (In formula (5), R ₁ , R ₂ and R ₃ are each independently hydrogen or hydroxyl group, or formula (6) (In formula (6), R ₄ is hydrogen or methyl, and R ₅ is hydrogen, methyl, ethyl or glycidyl.) represents that at least one of R ₁ , R ₂ and R ₃ is hydrogen, n is an integer above 1, and the upper limit is limited by the molecular weight described below).

Regarding the cellulose ester represented by the above formula (5), the content of the acyl group relative to the cellulose resin is in a range of more than 0 and 60 wt% or less, and preferably in a range of 5 to 55 wt%.

Regarding the cellulose ester represented by the above formula (5), the content of the hydroxyl group of the cellulose resin is 0 to 6 wt%, the content of the acetyl group is 0 to 40 wt%, and the propyl group or/and The butyl group content is 0 to 55 wt%, and the content of the group represented by formula (6) is preferably in the range of 0 to 20 wt%. The so-called "wt%" refers to the weight % of hydrogen, hydroxyl groups or groups represented by formula (6) relative to the weight of cellulose.

Commercial products of such cellulose esters include cellulose acetate such as CA-398-3, CA-398-6, CA-398-10, CA-398-30, CA-394-60S, etc. , examples of cellulose acetate butyrate include CAB-551-0.01, CAB-551-0.2, CAB-553-0.4, CAB-531-1, CAB-500-5, CAB-381-0.1, Examples of cellulose acetate propionate include CAB-381-0.5, CAB-381-2, CAB-381-20, CAB-381-20BP, CAB-321-0.1, CAB-171-15, etc. 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), etc. Among these, from the viewpoint of solubility in a solvent, cellulose acetate butyrate and cellulose acetate propionate are preferred. Furthermore, the above-mentioned cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate are reacted with (meth)acrylic acid, in the presence of an oxidizing agent such as benzyl peroxide, By reacting methyl (meth)acrylate, ethyl (meth)acrylate, glycidyl (meth)acrylate, etc., a cellulose derivative containing a group represented by formula (6) can be obtained. By using a cellulose derivative containing a group represented by the formula (6), the evaluation results of adhesion can be improved.

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

In addition, the glass transition temperature Tg in this specification is the glass transition temperature measured based on the method described in "5.17.5 DSC method" of JIS C 6481:1996 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 material of the cellulose derivative used in the present invention can also be made 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. The compounding amount of (D) the cellulose derivative relative to 100 parts by mass of (A) the alkali-soluble polyamide imine resin (and the alkali-soluble polyimide resin of any component described below) is, for example, 0.5 parts by mass or more and 20 parts by mass or less, preferably 1 part by mass or more and 15 parts by mass or less, more preferably 4 parts by mass or more and 10 parts by mass or less. 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 the adhesion becomes good and the hardenability The viscosity of the resin composition is within an appropriate range. This is considered to be because (A) the alkali-soluble polyamide imine resin and (C) the thermosetting compound and (D) the cellulose derivative have good compatibility before thermal curing, and the polymer component is dispersed 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 thermal hardening moves to the film surface during the thermal hardening reaction, and the surface roughness (arithmetic mean roughness) of the cured film after thermal hardening is Ra) becomes larger by drying the coating film before thermal hardening. If the number average molecular weight and compounding amount of (D) cellulose derivative are set in the above range, the surface roughness after hardening (arithmetic mean roughness Ra) may be 0.1 μm or more and 1 μm or less.

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

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

Examples of the alkali-soluble polyimide resin (E) include a resin obtained by reacting a carboxylic acid anhydride component with an amine component and/or an isocyanate component. The alkali-soluble group can be introduced by using an amine component having a carboxyl group or a phenolic hydroxyl group. Furthermore, the imidization may be carried out by thermal imidization, chemical imidization, or a combination of these.

Examples of the carboxylic anhydride component include tetracarboxylic anhydride, tricarboxylic anhydride, etc., but are not limited to these acid anhydrides. Any compound having an acid anhydride group and a carboxyl group that reacts with an amine group or an isocyanate group can be used. the derivative. Moreover, these carboxylic acid anhydride components can 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 a carboxyl group, diamines having a phenolic hydroxyl group, and the like can be used. The amine component is not limited to these amines, but an amine capable of introducing at least one functional group of a phenolic hydroxyl group or a carboxyl group must be used. Moreover, these amine components can 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 commonly used diisocyanates can be used. It is not limited to these isocyanates. Moreover, these isocyanate components can be used individually or in combination.

For the synthesis of (E) the 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 acid anhydrides, amines, and isocyanates of the raw materials and can dissolve these raw materials, and 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, dimethylacetamide Aprotic solvents such as terine 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 resin combines the alkali solubility (developerability) of the polyimide resin with other properties such as the mechanical properties of the cured product of the curable resin composition containing the polyimide resin. 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 takes into consideration the developability and the characteristics of the cured coating film, the mass average molecular weight Mw is preferably 100,000 or less, more preferably 1,000 to 100,000, and more preferably 2,000 to 50,000. .

When (E) alkali-soluble polyimide resin is added, from the viewpoint of improving heat resistance and developability, (A) alkali-soluble polyamide imine resin and (E) alkali-solubility For the mixing ratio of polyimide resin, the mass ratio can be set at 98:2~50:50, preferably at 95:5~50:50, and at 95:5~70:30. Better.

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

[Polymer resin] To the curable resin composition of the present invention, a well-known and commonly used polymer resin can be added for the purpose of improving the flexibility and touch dryness of the obtained cured product. Examples of such polymer resins include polyester-based, phenoxy resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, polyamide-based polymers, elastomers, and the like. One type of polymer resin may be used alone, or two or more types may be used in combination.

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

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

[Organic solvent] In the curable resin composition of the present invention, an organic solvent may be added when preparing the resin composition or adjusting the viscosity of coating on a substrate or carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such an organic solvent may be used individually by 1 type, and may be used 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 accelerators, antioxidants, and ultraviolet absorbers as necessary. Commonly known and customary ones can be used.

In addition, well-known and commonly used tackifiers such as micro-powdered silica, hydrotalcite, organic bentonite, and montmorillonite, defoaming agents such as silicone-based, fluorine-based, and polymer-based defoamers and/or smoothing agents, and silane coupling agents can be added. Mixtures, anti-rust agents and other well-known and commonly used additives.

＜Laminated structure＞ The laminated structure of the present invention is one in which 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 with two or more resin layers. When setting up 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 laminated. , and a laminated structure of 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 base material 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 laminate structure is supported or protected by a film. The resin layer (A) can be made 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, the curable resin composition of the present invention constituting the resin layer is diluted with an organic solvent to adjust to an appropriate viscosity on a carrier film (support film), and is coated according to conventional methods using a known method such as a notch wheel coater. When the resin layer has a laminated structure, the coated resin composition is replaced, or the coating operation is repeated without replacement. After drying for 1 to 30 minutes, usually at a temperature of 50 to 130°C, a dry coating film of the resin layer in the B-stage state (semi-hardened state) is formed on the carrier film, and the laminated structure of the present invention can be produced. The resin layer of this laminated structure is a so-called dry film. On this dry film, a peelable coating (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, conventionally known plastic films can be used. For the cover film, when the cover film is peeled off, the one with smaller adhesion force between the resin layer and the carrier film is preferred. There are no special restrictions on the thickness of the carrier film and the coating. Generally, the range of 10 to 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＞ The curable resin composition of the present invention and the resin layer of the laminated structure of the present invention can be used, for example, those which are effective for electronic components such as flexible printed wiring boards. Specific examples include a layer of the curable resin composition of the present invention or a resin layer of a laminated structure formed on a flexible printed wiring base material, patterned by irradiation with light, and then patterned with a developer. Flexible printed wiring boards, etc., which are hardened materials of insulating films.

The manufacturing method of the flexible printed wiring board will be described in detail below.

＜Manufacturing method of flexible printed wiring board＞ An example of manufacturing 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 the step of coating the curable resin composition of the present invention on a flexible printed wiring base material forming a conductor circuit, or bonding the resin layer of the laminated structure of the present invention to form a resin layer (layer forming step) , the step of irradiating the resin layer with active energy rays into a pattern (exposure step), and the step of alkali development of the exposed resin layer to form a patterned resin layer image (development step) Manufacturing method. Moreover, if necessary, after alkali development, photohardening or thermal hardening (post-hardening step) is further performed, the resin layer is completely hardened, and a cured film is formed, and a highly reliable flexible printed wiring board can be obtained.

Moreover, the manufacturing of the flexible printed wiring board using the resin layer of the curable resin composition of this invention or the laminated structure of this invention can also be performed according to other procedures. That is, it includes the step of coating the curable resin composition of the present invention on a flexible printed wiring base material forming a conductor circuit, or bonding the resin layer of the laminated structure of the present invention to form a resin layer (layer forming step) , the step of irradiating the resin layer with active energy rays into a pattern (exposure step), the step of heating the exposed resin layer (heating (PEB) step), and performing alkali development on the heated resin layer to form A method for producing a patterned resin layer image (development step). In addition, if necessary, after alkali development, photocuring or thermal curing (post-curing step) is further performed to completely cure the resin layer and form a cured film, thereby obtaining a highly reliable flexible printed wiring board. [Example]

The present invention will be described in detail below using examples, but the present invention is not limited only to these examples. In addition, unless otherwise specified below, "part" means the mass part of solid content.

((A) Synthesis of alkali-soluble polyamide imine resin) [Synthesis example 1] In a four-neck 300 mL flask equipped with a nitrogen gas introduction tube, a thermometer, and a stirrer, an aliphatic diamine derived from a dimer acid with a carbon number of 36 (manufactured by Croda Japan, product name PRIAMINE 1075) as the dimer diamine (a) 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, 30.12g (0.152mol) of cyclohexane-1,2,4-tricarboxylic anhydride (c) and 3.07g (0.016mol) 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., and the water produced together with toluene was removed. The mixture was kept for 3 hours, and then cooled to room temperature to obtain a solution containing a acyl imide compound.

In the solution containing the obtained acyl imide compound, 14.30 g (0.068 mol) of trimethylhexamethylene diisocyanate as the diisocyanate compound was put, and the solution was kept at 160° C. for 32 hours. After diluting 21.4 g of ketone, a solution (A-1) containing (A) alkali-soluble polyamide imine resin was obtained. The obtained polyamide imine 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 content of dimer diamine (a) of 40.0% by mass.

[Synthesis example 2] In a four-neck 300 mL flask equipped with a nitrogen gas introduction tube, a thermometer, and a stirrer, an aliphatic diamine derived from a dimer acid with a carbon number of 36 (manufactured by Croda Japan, product name PRIAMINE 1075) as the dimer diamine (a) was placed 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. Further, 30 g of toluene was added, the temperature was raised to 160°C, and the water co-generated with toluene was removed. The solution was kept for 3 hours, and cooled to room temperature to obtain a solution containing a acyl imide.

In the solution containing the obtained acyl imide compound, 6.90 g (0.033 mol) of trimethylhexamethylene diisocyanate and 8.61 g (0.033 mol) of dicyclohexylmethane diisocyanate as diisocyanate compounds were charged, and the mixture was heated at 160 The solution (A-2) containing (A) alkali-soluble polyamide imine resin was obtained after maintaining it at a temperature of ℃ for 32 hours and diluting with 36.8 g of cyclohexanone. The obtained polyamide imine resin had a mass average molecular weight Mw of 5840, a solid content of 40.4% by mass, an acid value of 62 mgKOH/g, and a content of dimer diamine (a) of 40.1% by mass.

[Synthesis example 3] In a four-neck 300mL flask equipped with a nitrogen inlet tube, a thermometer, and a stirrer, add 6.98 g of 2,2'-bis[4-(4-aminophenoxy)phenyl]propane and 3,5-diaminobenzoin. 3.80 g of acid, 8.21 g of polyetherdiamine (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, and the water co-generated with toluene was removed. The mixture was kept for 3 hours and cooled to room temperature to obtain a acyl imide solution.

To the obtained acyl imide solution, 9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were put, and the mixture was maintained at a temperature of 160° C. for 32 hours. Thus, an alkali-soluble polyamide imine resin solution (A-3) containing a carboxyl group (A) is obtained. The solid content is 40.1% by mass, and the acid value is 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 22.4g of 3,3'-diamino-4,4'-dihydroxydiphenyl sulfide and 2,2'- 8.2g of bis[4-(4-aminophenoxy)phenyl]propane, 30g of NMP, 30g of γ-butyrolactone, 27.9g of 4,4'-oxydiphthalic anhydride and 3.8g of trimellitic anhydride, in Under nitrogen environment, stir at room temperature at 100 rpm for 4 hours. Next, 20 g of toluene was added, and the toluene and water were distilled off at 150 rpm at a silicon oxygen bath temperature of 180°C and stirred for 4 hours to obtain a polyimide resin solution (PI-1) having phenolic hydroxyl groups and carboxyl groups.

The acid value of the obtained resin (solid content) was 18 mgKOH, Mw was 10,000, and 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, 64 g of methyl ethyl ketone and 16 g of CAB-553-0.4 (cellulose acetate derivative, manufactured by Eastman Chemical Co., Ltd.) were placed, and the temperature was maintained at 75°C. Stir for 1 hour. Next, the mixture obtained by mixing 15 g of methyl methacrylate and 1 g of benzyl peroxide in advance was added dropwise over 3 hours. After completion of the dropwise addition, a mixture prepared by mixing 0.5g of benzyl peroxide and 5g of methyl ethyl ketone in advance was added dropwise over 1 hour while maintaining the temperature at 75°C. Stirring was continued for 3 hours at 75°C and then cooled. 61 g of methyl ethyl ketone was added to the mixture and stirred to obtain a resin solution (CA-1). Furthermore, the heating residue of the resin solution CA-1 was 20.0% by 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 derivative, manufactured by Eastman Chemical Co., Ltd.) were placed, and the process was carried out at 75°C for 1 Stir for hours. Next, a mixture obtained by mixing 15 g of glycidyl methacrylate and 1 g of benzyl peroxide in advance was added dropwise over 3 hours. After completion of the dropwise addition, a mixture obtained by mixing 0.5g of benzyl peroxide and 5g of methyl ethyl ketone in advance was added dropwise over 1 hour while maintaining the temperature at 75°C. Stirring was continued for 3 hours at 75°C and then cooled. 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 the resin solution CA-2 was 20.0% by mass.

[Examples of the curable resin composition according to 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 Table 1 below, each material of the curable resin composition of Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 was added, and after preliminary mixing with a mixer, A three-roller mill kneads and adjusts 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 described above, a resin layer (dry coating film) in the B-stage state (semi-cured state) of each curable resin composition was formed as follows, and the resolution was evaluated. As will be described later, for the flexible wiring board having the resin layer in the B-stage state (semi-cured state) and the flexible wiring board having the cured product of the resin layer, the B-stage state (semi-cured state)/heat was evaluated. Surface roughness of each coating film after hardening. Therefore, for a flexible wiring board having a cured resin layer, its heat resistance (soldering heat resistance), gold plating resistance (chemical resistance), flexibility, and adhesion are also evaluated. The results are shown in Table 1.

<1-2. Formation of resin layer> A flexible printed wiring base material with a circuit having a copper thickness of 18 μm was prepared, and preprocessed using MEC's CZ-8100. Thereafter, each of the curable resin compositions obtained in Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-3 was applied to the pre-treated flexible printed wiring base material until dry. The film thickness is the film thickness described in Table 1. Thereafter, the resin layer (dry coating film) in the B-stage state (semi-hardened state) was formed after drying for 30 minutes in a hot air circulation drying oven at 90°C.

<1-3. Preparation of evaluation substrate> For the uncured resin layer on each flexible printed wiring base material to form the above-mentioned resin layer, first use an exposure device equipped with a metal halide lamp (HMW-680-GW20: (manufactured by Oak Manufacturing Co., Ltd.), through a negative mask (Negative mask), perform pattern exposure at 300mJ/ ^cm2 to form an opening with a diameter of 200μm. Thereafter, a PEB step was performed at 90°C for 30 minutes, then developed (30°C, 0.2MPa, 1 mass% Na ₂ CO ₃ aqueous solution) for 60 seconds, and thermally cured at 150°C × 60 minutes to produce a hardened 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 base material as described in <1-2. Formation of the resin layer>, or for the resin layer (dry coating film) as described in <1-3 .Preparation of evaluation substrate>The arithmetic mean surface roughness Ra of the resin layer on the evaluation substrate after heat curing was produced as described. The measured value is the average of five arbitrary 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 main body (control part) of the shape measurement laser microscope (same as VK-X100) and the VK observation application (VK-H1VX manufactured by Keyence Co., Ltd.), mount the support film with the intermediate layer measured on the x-y stage ( Take the side with the middle layer as the upper part). Rotate the lens of the microscope part (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 10x with a magnification of 100x, and use the autofocus function of the image observation mode of the VK observation application (same as VK-H1VX) to focus on the specimen surface. Select the simple mode of the shape measurement tab 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. The VK analysis application (VK-H1XA manufactured by Keyence Co., Ltd.) was started, the obtained surface image film was displayed, and then the slope was corrected.

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, select JIS B 0601-1994, select the horizontal line with the measurement line button, and display the horizontal line anywhere in the surface image. Press the OK button to obtain the arithmetic mean surface roughness. The numerical value of degree Ra. Furthermore, horizontal lines are displayed at four different places in the surface image to obtain the numerical value of each arithmetic mean surface roughness Ra. The average value of the five obtained values was calculated as the arithmetic mean surface roughness Ra value of the surface of each resin layer.

<1-5. Evaluation of resolution> For the B-stage state (semi-hardened state) of the resin layer (drying) formed on the flexible printed wiring base material 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, the results of each Example, Comparative Example 1-1 and Comparative Example 1-3 The dry coating film does not reach 0.1μm. The arithmetic mean roughness Ra of the dried coating film of Comparative Example 1-2 was 0.1 or more. For each of these dried coating films, an exposure device (HMW-680-GW20: manufactured by Oak Manufacturing Co., Ltd.) equipped with a metal halide lamp was first used to perform pattern exposure at 300 mJ/cm ² through a negative tool to form openings with a diameter of 150 μm and 200 μm. . The substrate with the exposed resin layer was heated at 90° C. for 30 minutes.

Thereafter, the substrate was immersed in a 1 mass % sodium carbonate aqueous solution at 30° C. and developed 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 150μm is well formed. ○: The opening pattern of 200 μm is well formed, but the opening pattern of 150 μm is slightly poor. ×: Although the unexposed portion showed developability, the opening pattern formation of 200 μm was poor (resolution was insufficient).

<1-6. Evaluation of heat resistance (welding heat resistance)> For the evaluation substrate prepared as described in <1-3. Preparation of evaluation substrate>, apply rosin-based flux, immerse it in a soldering bath preset at 260°C for 20 seconds (10 seconds × 2 times), and observe the hardened coating film Expansion and peeling to evaluate heat resistance (welding heat resistance). The evaluation criteria are as follows.

◎: No swelling or peeling occurred even after immersing for 10 seconds x 2 times. ○: No swelling or peeling occurred even after 10 seconds of immersion once. However, peeling occurred after the second immersion. ×: Swelling and peeling will occur after dipping for 10 seconds × once.

<1-7. Evaluation of gold plating resistance (chemical resistance)> An evaluation substrate was prepared as described in <1-3. Preparation of evaluation substrate>, and the evaluation was performed by the following method.

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

○: There is no penetration between the substrate and the hardened coating film. △: Penetration is confirmed between the substrate and the cured coating film. ×: Part of the hardened coating film peeled off.

＜1-8. Flexibility (MIT test)＞ Each evaluation substrate produced as described in <1-3. Preparation of evaluation substrate> was used as a test piece, and an MIT folding fatigue testing machine type D (manufactured by Toyo Seiki Co., Ltd.) was used to perform MIT using 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 on 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. Carry out bending and measure the number of times (times) of back and forth bending until it breaks. Moreover, the test environment is at 25°C and the radius of curvature is set at R=0.38mm. The evaluation criteria are as follows.

◎: After being bent more than 200 times, there are no cracks in the hardened coating at the bends. 〇: No cracks were produced after bending from 170 to 199 degrees. △: After being bent 150 to 169 times, no cracks were produced. ×: Cracks occurred when the number of bending times was 149 or less.

<1-9. Adhesion> Regarding the resin layer in the B-stage state (semi-hardened state) on each flexible printed wiring base material 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 dry coating film was measured, the dry coating films of each Example, Comparative Example 1-1 and Comparative Example 1-3 were not up to 0.1μm. The arithmetic mean roughness Ra of the dried coating film of Comparative Example 1-2 was 0.1 or more. For each of these dried coating films, solid exposure was performed at 300 mJ/cm ² through a negative tool using an exposure device (HMW-680-GW20: manufactured by Oak Manufacturing Co., Ltd.) equipped with a metal halide lamp. Thereafter, a PEB step was performed at 90°C for 30 minutes, followed by development (30°C, 0.2MPa, 1 mass % Na ₂ CO ₃ aqueous solution) for 60 seconds, and thermal hardening at 150°C × 60 minutes to produce a form-hardened product. 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- The dry coating film of 3 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.

The obtained evaluation substrate was cut into a square of 2cm on each side and 10 pieces were overlapped. Then, it was placed at each temperature of 20, 30, 40, and 60°C for 72 hours, and then the adhesion was confirmed. The evaluation criteria are as follows.

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

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

A-1: Polyamide imine resin-containing solution produced by [Synthesis Example 1] of the above ((A) Synthesis of alkali-soluble polyamide imine resin) A-2: Polyamide imine resin-containing solution produced by [Synthesis Example 2] of the above ((A) Synthesis of alkali-soluble polyamide imine resin) A-3: Polyamide imine resin-containing solution produced by [Synthesis Example 3] of the above ((A) Synthesis of alkali-soluble polyamide imine 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 47mgKOH/g (manufactured by Kyeisha Chemical Co., Ltd.) IRGACURE OXE02: oxime-based photopolymerization initiator (manufactured by BASF) 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 type 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 development, and a dry film with a thickness of 2 to 100 μm is formed from a curable resin composition that forms a cured film by exposure and heat treatment. A resin formed when the arithmetic mean roughness Ra of the dried coating film is less than 0.1 μm during coating, and the arithmetic mean roughness Ra of the cured film after thermal curing of the dry coating film is 0.1 μm or more and 1 μm or less. The layer (dry coating film) has excellent resolution, and the cured coating film (hardened material) after thermal curing is not only excellent in heat resistance, gold plating resistance, and flexibility, but also has small adhesion after high-temperature storage.

In addition, from the comparison between Examples 1-1, 1-2, 1-4, 1-9 to 1-11 and Examples 1-3, 1-5 to 1-8, and 1-12, it can be seen that drying When the film thickness of the coating film is set to 3 μm or more and 80 μm or less, and the arithmetic mean roughness Ra of the dry coating film is set to less than 0.05 μm, the arithmetic value of the cured film after thermal curing relative to the arithmetic mean roughness Ra of the dry coating film When the ratio of the average roughness Ra (the arithmetic mean roughness Ra of the cured film after thermal hardening/the arithmetic mean roughness Ra of the dry coating film) is 6 or more, the resolution of the formed resin layer (dry coating film) will be greatly improved. The ground is increased, and the bonding of the thermally cured cured coating film (cured product) after being stored at high temperature becomes further reduced.

[Example of the curable resin composition according to 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 curable resin compositions of Examples 2-1 to 2-8 and Comparative Examples 2-1 to 2-2 were added, and these were preliminarily mixed with a mixer. A three-roller mixer kneads and adjusts each curable resin composition to be formed into a resin layer. In addition, unless otherwise stated, the values in Table 2 are parts by mass of solid content.

For each curable resin composition described above, a resin layer (dry coating film) in the B-stage state (semi-cured state) of each curable resin composition was formed as follows, and the developability (alkali solubility) was evaluated. As will be 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> Prepare a flexible printed wiring base material on which a circuit with a copper thickness of 18 μm is formed, and perform preprocessing using MEC's CZ-8100. 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 base material 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 (dry coating film) in a B-stage state (semi-hardened state).

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

<2-4. Evaluation of developability (alkali solubility)> Regarding the B-stage state (semi-cured state) formed on the flexible printed wiring base material as described in <2-2. Formation of the resin layer> The resin layer (dry coating film) is first pattern-exposed using an exposure device (HMW-680-GW20: manufactured by Oak Manufacturing Co., Ltd.) equipped with a metal halide lamp at 300 mJ/cm ² through a negative tool to form an opening with a diameter of 200 μm. The substrate with the exposed resin layer was heated at 90° C. for 30 minutes.

Thereafter, the substrate was immersed in a 1 mass % sodium carbonate aqueous solution at 30° C. and developed 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 part shows development resistance, the unexposed part shows developability, and the pattern is formed well. ×: The unexposed portion showed developability, but poor resolution pattern formation (insufficient resolution).

<2-5. Evaluation of heat resistance (welding heat resistance)> For the evaluation substrate prepared as described in <2-3. Preparation of evaluation substrate>, apply rosin-based flux, immerse it in a soldering bath preset at 260°C for 20 seconds (10 seconds × 2 times), and observe the hardened coating. The film expands and peels off to evaluate the heat resistance (welding heat resistance). The evaluation criteria are as follows. ◎: No swelling or peeling even after dipping for 10 seconds x 2 times. ○: Although there was no swelling or peeling even after 10 seconds of immersion once, peeling occurred after the second immersion. ×: Swelling and peeling occurred when immersed once for 10 seconds.

<2-6. Evaluation of gold plating resistance (chemical resistance)> Use the evaluation substrate produced as described in <2-3. Preparation of evaluation substrate> and perform evaluation according to the following method.

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

○: There is no penetration between the substrate and the hardened coating film. △: Penetration between the substrate and the cured coating film is confirmed. ×: Part of the hardened coating film peels off.

＜2-7. Flexibility (MIT test)＞ Each evaluation substrate produced as described in <2-3. Preparation of evaluation substrate> was used as a test piece, and an MIT folding fatigue testing machine type D (manufactured by Toyo Seiki Co., Ltd.) was used to perform MIT using 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 on the device. Under the load F (0.5kgf) state, the test piece 1 is placed vertically on the clamp 2, the bending angle α is 135 degrees, and the speed is set at 175 cpm, and the number of times (times) of back-and-forth bending until breakage was measured. Moreover, the test environment is at 25°C and the radius of curvature is set at R=0.38mm. The evaluation criteria are as follows.

◎: After being bent more than 200 times, there are no cracks in the hardened coating at the bends. 〇: No cracks were produced after bending from 170 to 199 degrees. △: After being bent 150 to 169 times, no cracks were produced. ×: Cracks occurred when the number of bending times was 149 or less.

<2-8. Adhesion> Regarding the B-stage state (semi-hardened state) of the resin layer ( (dry the coating film), first use an exposure device equipped with a metal halide lamp (HMW-680-GW20: manufactured by Oak Manufacturing Co., Ltd.) to perform solid exposure at 300 mJ/cm ² through a negative tool. Thereafter, a PEB step was performed at 90° C. for 30 minutes, and then developed (30° C., 0.2 MPa, 1 mass % Na ₂ CO ₃ aqueous solution) for 60 seconds, and heat cured at 150° C. × 60 minutes to produce a formed process. Flexible printed wiring board (evaluation board) with a cured resin layer (cured coating film).

The obtained evaluation substrate was cut into a square of 2cm on each side and 10 pieces were overlapped. Then, it was placed at each temperature of 20, 30, 40, and 60°C for 72 hours, and then the adhesion was confirmed. The evaluation criteria are as follows.

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

The details of the ingredients 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: Polyamide imine resin-containing solution produced in [Synthesis Example 3] of the above ((A) Synthesis of alkali-soluble polyamide imine resin) A-1: Polyamide imine resin-containing solution produced in [Synthesis Example 1] of the above ((A) Synthesis of alkali-soluble polyamide imine resin) P7-532: Polyurethane acrylate, acid value 47 mgKOH/g (manufactured by Kyeisha Chemical Co., Ltd.) IRGACURE OXE02: Oxime-based photobase generator (manufactured by BASF) 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 (manufactured by Eastman Chemical Company) (the parts in Table 2 represent the mass parts of the solid content of the 20wt% DPM solution) CA-1: ((D) Synthesis of cellulose derivatives) CAB-553-0.4 produced by [Synthesis Example 5] denatured with methyl methacrylate, 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 type epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (manufactured by Mitsubishi Chemical Corporation)

As shown in Table 2, it can be seen from the comparison between the examples and the comparative examples that the curable resin composition contains (A) alkali-soluble polyamide imine resin, (C) thermosetting compound and ( B) In addition to the photobase generator, it also contains (D) cellulose derivatives. The formed resin layer has excellent developability. The cured resin layer not only has excellent heat resistance, gold plating resistance, and flexibility, but also has excellent adhesive properties. Together they are small.

In addition, from the comparison between Examples 2-1 to 2-2 and Examples 2-3 to 2-8, it can be seen that the addition amount ratio of (A) alkali-soluble polyamide imine resin to (E) When more alkali-soluble polyimide resin is used, the heat resistance can be further improved. In addition, from the comparison between Example 2-3 and Examples 2-7 to 2-8, it can be seen that by using (D) a cellulose derivative containing a group represented by formula (6), the paste can be further reduced. fit, that is, the fit evaluation result is good. In addition, from the comparison between Example 2-3 and Example 2-6, it can be seen that as the alkali-soluble polyamide imine resin (A), a polyamide imine resin having a structure shown in formula (1) and formula (2) is used. The polyamide imine resin with the structure shown can also improve the softness and fit.

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

Claims (8)

A curable resin composition characterized by containing (A) alkali-soluble polyamideimide resin, (B) photobase generator, (C) thermosetting compound and (D) cellulose derivative, The number average molecular weight of the cellulose derivative (D) is 5,000 to 500,000, and the compounding amount of the cellulose derivative (D) is 100 parts by mass of the alkali-soluble polyamide imine resin (A). It is 0.5 parts by mass or more and 20 parts by mass or less. The curable resin composition of claim 1, wherein the alkali-soluble polyamide imine resin (A) has a carboxyl group. The curable resin composition of claim 2, wherein the alkali-soluble polyamide imine resin (A) has a carboxyl group and a phenolic hydroxyl group. The curable resin composition of claim 1, which further contains (E) alkali-soluble polyimide resin. The curable resin composition of claim 1, wherein the aforementioned (C) thermosetting compound is an epoxy resin. A laminated structure in which at least one side of the resin layer formed of the curable resin composition according to claim 1 is supported or protected by a film. A hardened product obtained from the curable resin composition according to claim 1 or the resin layer according to claim 6. An electronic component characterized by having an insulating film made of the hardened material according to claim 7.

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