CN118483872B - Photosensitive resin composition and photosensitive dry film - Google Patents

Abstract

The present invention discloses a photosensitive resin composition and a photosensitive dry film, wherein the photosensitive resin composition comprises the following raw material components in parts by mass: 48-68 parts of an alkali-soluble resin, 32-52 parts of a photopolymerizable monomer having at least one ethylenic unsaturated bond, 2.7-4.5 parts of a photopolymerization initiator, and 0.1-0.3 parts of a sensitizer; the photopolymerization initiator comprises a carbazolyl acridine compound shown in Formula I. The present invention combines the carbazolyl acridine compound, the initiator and the sensitizer, and utilizes the energy transfer or electron transfer of the carbazolyl acridine compound to transfer or excite energy to the sensitizer and the photopolymerization initiator 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole to initiate photopolymerization, so that the dry film of the present invention can be used in both a touch exposure machine and a laser drawing exposure machine.

Description

Photosensitive resin composition and photosensitive dry film

Technical Field

The present invention relates to the technical field of photosensitive materials, and in particular to a photosensitive resin composition and a photosensitive dry film.

Background Art

There are two types of exposure machines: laser direct drawing exposure machines that perform exposure by moving the laser at high speed, and contact exposure machines that use mercury vapor arc lamps, high-pressure mercury lamps, xenon lamps, etc. to effectively radiate ultraviolet light. Although the contact exposure method has low production efficiency, it is still indispensable in the market because of special applications.

To cope with these two exposure methods, there are two types of dry films on the market: direct drawing dry film for laser direct drawing and ordinary dry film for contact exposure. Direct drawing dry film has low exposure energy, high light sensitivity and high production efficiency. However, when used in a contact exposure machine, it is easy to cause voids caused by insufficient curing at the bottom of the dry film, and the adhesion is significantly reduced, so it cannot be used in a contact exposure machine. Ordinary dry film has low light sensitivity, and when used in a direct drawing machine, the energy is extremely high and the production efficiency is extremely low. Therefore, it is necessary to develop a dry film that can be used for both direct drawing exposure machines and contact exposure machines.

Summary of the invention

The present invention provides a photosensitive resin composition and a photosensitive dry film to solve the technical problem that the existing dry film cannot have good curing ability on a contact exposure machine and high production efficiency on a direct drawing exposure machine.

According to one aspect of the present invention, a photosensitive resin composition is provided, the photosensitive resin composition comprising the following raw material components in parts by mass: 48-68 parts of an alkali-soluble resin, 32-52 parts of a photopolymerizable monomer having at least one ethylenically unsaturated bond, 2.7-4.5 parts of a photopolymerization initiator, and 0.1-0.3 parts of a sensitizer; the sensitizer is tetraethyl Michler's ketone;

The photopolymerization initiator comprises a carbazolyl acridine compound represented by formula (I) and 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole; the mass ratio of the carbazolyl acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.2-0.5:2.5-4;

(I)

Wherein, R is one of an alkyl group, an alkoxy group, an aryl group, a substituted aryl group, and a substituted heteroaryl group.

Furthermore, the photosensitive resin composition comprises the following raw material components in parts by mass: 48-58 parts of an alkali-soluble resin, 32-42 parts of a photopolymerizable monomer having at least one ethylenically unsaturated bond, 3-3.85 parts of a photopolymerization initiator, and 0.15-0.2 parts of a sensitizer.

Furthermore, the mass ratio of the carbazole-based acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.35-0.5:3.5-4.

Furthermore, the mass ratio of the carbazole-based acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.35:3.5.

Furthermore, the mass ratio of the carbazole-based acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.5:2.5.

Furthermore, the carbazole-based acridinium compound includes any one of 3-(9-acridinyl)-carbazole, N-ethyl-3-(9-acridinyl)-carbazole, N-ethoxy-3-(9-acridinyl)-carbazole, N-phenyl-3-(9-acridinyl)-carbazole and N-chlorophenyl-3-(9-acridinyl)-carbazole.

Further, the photopolymerizable monomer having at least one ethylenically unsaturated bond includes at least three of 2,2-bis(4-(meth)acryloxypolyethoxy)phenylpropane, nonylphenoxytetraethyleneoxyacrylate, trimethylolpropaneethoxy triacrylate and polyurethane acrylic resin.

Furthermore, the alkali-soluble resin includes methacrylic acid, methyl 2-methyl-2-acrylate, ethyl 2-acrylate and 2-ethylhexyl acrylate.

The alkali-soluble resin has an acid value of 130 mgKOH/g, a weight average molecular weight of 90,000 g/mol as measured by GPC, and a solid content of 42.5%.

Furthermore, the photosensitive resin composition further comprises 0.1-1 parts by mass of an additive, wherein the additive comprises malachite green and/or colorless crystal violet.

According to another aspect of the present invention, a photosensitive dry film is provided, comprising a substrate layer, a photosensitive material layer, and a protective film layer, wherein the photosensitive material layer is the above-mentioned photosensitive resin composition.

The present invention has the following beneficial effects:

The structure of the compound containing acridine designed by the present invention is an asymmetric structure, and the 9th position is composed of different substituted carbazoles. The carbazole group at the 9th position has a good conjugation effect with acridine, so that the absorption intensity of the molecule at 405nm is significantly increased. At the same time, the N in the carbazole group is composed of different alkyl chains, alkoxyl chains and other long chains, which can be used to adjust the solubility in the formula. Carbazole-based acridine compounds are usually used in laser drawing exposure machines. They can release free radicals under longer wavelength (lower energy) conditions by absorbing lower light energy.

The initiator 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is usually used in contact exposure machines. It absorbs light slowly and needs to absorb higher light energy. With the help of sensitizers, it can release free radicals and initiate photopolymerization. 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole needs to absorb higher light energy, so the bottom of the dry film is fully polymerized.

Therefore, the present invention combines carbazole-based acridine compounds, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole and sensitizers, and utilizes the energy transfer or electron transfer of carbazole-based acridine compounds to transfer or excite energy to the sensitizer and photopolymerization initiator 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole to generate primary active species (generally free radicals), which enable the formulation system to rapidly undergo cross-linking and curing reactions between oligomers and active diluents under the irradiation of light sources, which is one of the important determining factors of the photocuring rate and degree of photocuring, thereby enabling the dry film of the present invention to be used in both touch-type exposure machines and laser drawing exposure machines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the reaction principle of carbazole-based acridine compounds under longer wavelength conditions.

DETAILED DESCRIPTION

The following is a detailed description of the embodiments of the present invention, but the present invention can be implemented in many different ways as defined and covered below.

In one aspect of the present invention, a photosensitive resin composition is provided, the photosensitive resin composition comprising the following raw material components in parts by mass: 48-68 parts of an alkali-soluble resin, 32-52 parts of a photopolymerizable monomer having at least one ethylenically unsaturated bond, 2.7-4.5 parts of a photopolymerization initiator, and 0.1-0.3 parts of a sensitizer; the sensitizer is tetraethyl Michler's ketone;

The photopolymerization initiator comprises a carbazolyl acridine compound represented by formula (I) and 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole represented by formula (II); the mass ratio of the carbazolyl acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.2-0.5:2.5-4;

(I)

Wherein, R is one of an alkyl group, an alkoxy group, an aryl group, a substituted aryl group, and a substituted heteroaryl group.

(II)

Acridine compounds have been widely used as photoinitiators in photocuring systems. A typical example is the commonly used 9-phenylacridine. This type of compound has good absorption at a wavelength of 380-405nm, but the absorption intensity of the compound with the existing structure at 405nm is not high, resulting in poor initiation efficiency and effect. At the same time, the existing structure often has a symmetrical structure, resulting in poor solubility in the formulation system and easy precipitation, so its use is limited.

The structure of the compound containing acridine is redesigned to be an asymmetric structure, wherein the 9th position is composed of different substituted carbazoles, and the carbazole group at the 9th position has a good conjugation effect with acridine, so that the absorption intensity of the molecule at 405nm is significantly increased. Meanwhile, N in the carbazole group is composed of different long chains such as alkyl chains and alkoxy groups, and the solubility performance in the formula can be adjusted by them.

This photopolymerization initiator has high light absorption efficiency. It only needs to absorb relatively low light energy to release free radicals and initiate photopolymerization. It is usually used in direct-drawing exposure machines. Because carbazole-based acridine compounds absorb light quickly, the negative effects that may occur are: insufficient polymerization at the bottom of the dry film and the generation of voids. When carbazole-based acridines encounter other initiators with slower light absorption, such as 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, they will play the role of sensitizers, transferring or exciting energy to the slower absorbing initiator, thereby reducing their own light absorption efficiency and promoting polymerization at the bottom of the dry film.

Carbazole-based acridine compounds can undergo photophysical processes to a certain excited state after absorbing light energy under longer wavelength (lower energy) conditions, and then undergo intramolecular or intermolecular energy transfer to another molecule (sensitizer or initiator) to generate primary active species (generally free radicals), and then transfer or excite the energy to the sensitizer and initiator through energy transfer or electron transfer to generate free radicals, thereby causing the unsaturated photopolymerizable monomer to undergo photopolymerization curing reaction. It can effectively meet the current direct drawing exposure requirements. The reaction principle diagram is shown in Figure 1.

2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole absorbs light slowly and needs to absorb higher light energy with the help of sensitizers to release free radicals and initiate photopolymerization. Under ultraviolet light or laser irradiation, the sensitizer absorbs light energy and undergoes a photophysical process to a certain excited state, and then intramolecular or intermolecular energy transfer occurs and is transferred to the initiator 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, thereby initiating the polymerization and curing reaction of unsaturated monomers. It is usually used in contact exposure machines. 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole needs to absorb higher light energy, so the bottom of the dry film is fully polymerized. The disadvantage is that due to the absorption of higher light energy, the exposure efficiency is low, which affects the production efficiency. The present invention uses two initiators in combination. The carbazole-based acridine compound has high photosensitivity and can play the role of a sensitizer. It only needs to absorb low light energy (during production, the exposure light energy is set to be low and the time spent is short) to quickly generate free radicals and promote the photopolymerization curing reaction, thereby solving the problem of low production efficiency.

In some embodiments, the mass fraction of the alkali-soluble resin is 48-68 parts, for example, it can be 48 parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, 62 parts, 64 parts, 66 parts, 68 parts, etc., and can also be any combination range of the above values.

In an embodiment of the present invention, the mass fraction of the photopolymerizable monomer having at least one ethylenically unsaturated bond is 32-52 parts, for example, it can be 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 52 parts, 52 parts, etc., and can also be any combination range of the above values.

In an embodiment of the present invention, the mass fraction of the photopolymerization initiator is 2.7-4.5 parts, for example, it can be 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, etc., and can also be any combination range of the above values.

In an embodiment of the present invention, the mass fraction of the sensitizer is 0.1-0.25 parts, for example, it can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, etc., and can also be any combination range of the above values.

In a preferred embodiment, the photosensitive resin composition comprises the following raw material components in parts by weight: 48-58 parts of alkali-soluble resin, 32-42 parts of photopolymerizable monomer having at least one ethylenically unsaturated bond, 3-3.85 parts of photopolymerization initiator, and 0.15-0.2 parts of sensitizer.

In a preferred embodiment, the mass ratio of the carbazole-based acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole is 0.2-0.5:2.5-4.

In an embodiment of the present invention, the mass ratio of the carbazole-based acridine compound to 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole can be 0.35:3.5, or 0.5:2.5, or 0.2:4, etc.

In an embodiment of the present invention, the carbazole-based acridinium compound includes any one of 3-(9-acridinyl)-carbazole, N-ethyl-3-(9-acridinyl)-carbazole, N-ethoxy-3-(9-acridinyl)-carbazole, N-phenyl-3-(9-acridinyl)-carbazole and N-chlorophenyl-3-(9-acridinyl)-carbazole.

In a preferred embodiment, the synthesis route of the carbazole acridine compound is:

In a preferred embodiment, the preparation method of the carbazole-based acridinium compound (N-ethyl-3-(9-acridinyl)-carbazole) comprises the following steps:

Step (1) Preparation of intermediate M1:

3-bromocarbazole, diethyl sulfate, tetrabutylammonium bromide and toluene are mixed, and an aqueous sodium hydroxide solution is added dropwise under stirring at room temperature, and the temperature is raised to 84-90°C for reaction, and the temperature is lowered to 77-83°C, and then separated and concentrated to obtain an intermediate M1;

Step (2) Preparation of intermediate M2:

The intermediate M1 and tetrahydrofuran are mixed, n-butyl lithium and triisopropyl borate are added dropwise at (-75)-(-81)°C, and then the temperature is raised to room temperature. After the reaction is completed, an aqueous ammonium chloride solution is added to quench, and the mixture is separated and concentrated to obtain the intermediate M2;

Step (3) Preparation of carbazole-based acridine compounds:

The intermediate M2, 9-chloroacridine, potassium carbonate, toluene and water are added to a reaction container, and tetrakis(triphenylphosphine)palladium is added. The temperature is raised to reflux and stirred for reaction. After the reaction is completed, the temperature is lowered to 77-83°C, and the liquid is separated and concentrated to obtain a carbazole-based acridine compound N-ethyl-3-(9-acridinyl)-carbazole.

In a preferred embodiment, the reactions of step (2) and step (3) are carried out under a nitrogen atmosphere.

In a preferred embodiment, the photopolymerizable monomer having at least one ethylenically unsaturated bond includes at least three of 2,2-bis(4-(meth)acryloxypolyethoxy)phenylpropane, nonylphenoxytetraethylene oxide acrylate, trimethylolpropane ethoxylate triacrylate and polyurethane acrylate resin.

Among them, 2,2-bis(4-(meth)acryloyloxypolyethoxy)phenylpropane is a bisphenol A-based acrylate compound that can improve light height, clarity, adhesion and flexibility.

Nonylphenoxytetraethylene oxide acrylate has a certain water solubility and can improve the developing property and film removal property.

Trimethylol propane ethoxylate triacrylate is a multifunctional monomer that can increase the crosslinking density of the dry film after light curing and improve the adhesion of the dry film.

Polyurethane acrylate resin improves the flexibility of the dry film and can enhance the bonding ability between the photosensitive resin polymer and substrates such as copper clad laminates.

In a preferred embodiment, the alkali-soluble resin is composed of methacrylic acid, methyl 2-methyl-2-acrylate, ethyl 2-acrylate, and 2-ethylhexyl acrylate.

In the embodiments of the present application, the alkali-soluble resin is used as a film-forming agent of the dry film, with a large amount and a large molecular weight, so that the components of the photosensitive film are bonded to form a film, and it plays a role as a skeleton, which is an important component of the dry film. The alkali-soluble resin is weakly alkaline and can be washed away in the developer when no light reaction occurs. The use of the alkali-soluble resin (molecular weight, amount used) is related to the various properties of the photosensitive film, especially affecting the cover hole, adhesion, resolution and shape.

Before exposure to light, the photopolymerizable monomer having at least one ethylenically unsaturated bond, the alkali-soluble resin, and the photoinitiator are uniformly dispersed in the mixture. After exposure to ultraviolet light, the initiator generates free radicals, and the photopolymerizable monomer having at least one ethylenically unsaturated bond undergoes polymerization and cross-linking reaction, so that the alkali-soluble resin becomes a non-alkali-soluble cross-linked network structure.

In a preferred embodiment, the alkali-soluble resin has an acid value of 130 mgKOH/g, a weight average molecular weight of 90,000 g/mol as measured by GPC, and a solid content of 42.5%.

In a preferred embodiment, the photosensitive resin composition further comprises 0.1-1 parts by mass of an additive, wherein the additive comprises malachite green and colorless crystal violet.

In the embodiments of the present application, malachite green is a dye; and colorless crystal violet is a color development auxiliary agent to help the dry film change color after being exposed to light.

In a preferred embodiment, the photosensitive resin composition further comprises a solvent, and the solvent is toluene, methanol and acetone, and the mass ratio thereof is 15:7:7.

The embodiment of the second aspect of the present application further provides a photosensitive dry film, comprising a substrate layer, a photosensitive material layer, and a protective film layer, wherein the photosensitive material layer is the above-mentioned photosensitive resin composition.

The substrate layer is a PET layer, and the protective film layer is a PE protective film.

The preparation process of the photosensitive dry film is as follows:

(1) mixing an alkali-soluble resin, a photopolymerizable monomer having at least one ethylenically unsaturated bond, a photopolymerization initiator, a sensitizer, an additive, and a solvent in order according to a proportion and stirring them uniformly to obtain a dry film solution;

(2) The dry film liquid glue is coated onto a polyethylene terephthalate film using a film scraper, baked at 80°C, and protected using PE as a cover film to obtain a photosensitive dry film with a photosensitive resin composite layer thickness of 40 μm.

Example 1

The present embodiment provides a photosensitive resin composition, which includes the following raw material components in parts by mass: 58 parts of alkali-soluble resin, 42 parts of photopolymerizable monomer having at least one ethylenically unsaturated bond, 3.85 parts of photopolymerization initiator, 0.2 parts of sensitizer, and 0.54 parts of additives.

The alkali-soluble resin is methacrylic acid, 2-methyl-2-methyl acrylate, 2-ethyl acrylate, and 2-ethylhexyl acrylate, and the components are mixed in a mass ratio of 20:50:20:13.

The photopolymerizable monomer having at least one ethylenically unsaturated bond is 2,2-bis(4-(methyl)acryloxypolyethoxy)phenylpropane, nonylphenoxytetraethyleneoxyacrylate, trimethylolpropaneethoxylate triacrylate, and polyurethane propylene resin, and the components are mixed in a ratio of 25:5:5:7.

The photopolymerization initiator is a carbazole-based acridine compound and 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole, and the mass fractions of the two are 0.35 parts and 3.5 parts respectively.

The carbazole-based acridinium compound is 3-(9-acridinyl)-carbazole, and the synthesis steps of 3-(9-acridinyl)-carbazole include:

(1) Prepare the raw materials: 3-bromocarbazole (Tianjin Ai Chemical Industry (Shanghai) Co., Ltd.), diethyl sulfate (Shanghai MacLean Biochemical Technology Co., Ltd.), n-butyl lithium (Jiangsu Changjili New Energy Technology Co., Ltd.), tetrakis(triphenylphosphine)palladium (Dongguan Varisi Chemical Co., Ltd.), 9-chloroacridine (Shanghai Haohong Biopharmaceutical Technology Co., Ltd.), tetrabutylammonium bromide (Jiangsu Bisheng Chemical Co., Ltd.).

(2) Synthesis route

Preparation method of intermediate M1:

Weigh 3.25g (81.27mmol) of sodium hydroxide and prepare a 50% aqueous solution. Weigh 10.00g (40.63mmol) of 3-bromocarbazole, 5.01g (32.51mmol) of diethyl sulfate, 0.262g (0.812mmol) of tetrabutylammonium bromide and 50mL of toluene and add them to the reaction bottle. Slowly add the sodium hydroxide aqueous solution dropwise under stirring at room temperature. After completion, heat to reflux and react for 6h. After the reaction is completed, cool to 70℃, separate the liquid while hot, wash the organic phase with water once and concentrate it, and then purify the residue with 75% ethanol to obtain 10.20g of the product with a yield of 89.73%.

Preparation method of intermediate M2:

Weigh 10.00 g (35.75 mmol) of intermediate M1 and 100 mL of tetrahydrofuran into the reaction flask, replace with nitrogen, cool to -78 °C, add 15.64 mL (37.53 mmol) of 2.4 M n-butyl lithium dropwise, stir for 1 h after the addition is complete, add 10.08 g (53.62 mmol) of triisopropyl borate dropwise, keep warm and stir for 1 h after the addition is complete, warm to room temperature and continue to react for 16 h. After the reaction is complete, add 20 mL of ammonium chloride aqueous solution to quench. After quenching, evaporate the solvent, add 100 mL of dichloromethane and 100 mL of water to the residue, extract and separate, wash the organic phase with water once and concentrate to obtain 8.00 g of intermediate M2 with a yield of 91.74%.

Preparation method of carbazole acridine compounds:

Weigh 8.00g (32.79mmol) of intermediate M2, 7.01g (32.79mmol) of 9-chloroacridine, 6.80g (49.19mmol) of potassium carbonate, 50mL of toluene and 10mL of water into the reaction flask, replace with nitrogen, weigh 0.379g (0.33mmol) of tetrakis(triphenylphosphine)palladium into the reaction flask, heat to reflux and stir to react for 12h. After the reaction is completed, cool to 70℃, separate the liquid while hot, wash the organic phase with water once and concentrate, and then purify the residue with 95% ethanol to obtain 10.00g of product with a yield of 81.05%.

The preparation method of the photosensitive resin composition is as follows: a photoinitiator and a sensitizer are mixed in proportion, additives and solvents are added, and the mixture is stirred evenly by a stirrer. After the mixture is completely dissolved, an alkali-soluble resin and a photopolymerizable monomer having at least one ethylenically unsaturated bond are added in sequence in proportion, and the mixture is stirred with a stirrer until the mixture is fully uniform to prepare the photosensitive resin composition.

Example 2

The difference between this embodiment and embodiment 1 is that the photopolymerizable monomer having at least one ethylenically unsaturated bond in embodiment 1 is modified to 30 parts of 2,2-bis(4-(meth)acryloyloxypolyethoxy)phenylpropane, 5 parts of trimethylolpropane ethoxylate triacrylate, and 7 parts of polyurethane acrylate resin.

Example 3

The difference between this embodiment and embodiment 1 is that the photopolymerizable monomer having at least one ethylenically unsaturated bond in embodiment 1 is modified to 32 parts of 2,2-bis(4-(meth)acryloxypolyethoxy)phenylpropane, 5 parts of nonylphenoxytetraethylene oxide acrylate, and 5 parts of trimethylolpropane ethoxylate triacrylate.

Example 4

The difference between this embodiment and embodiment 1 is that the photopolymerizable monomer having at least one ethylenically unsaturated bond in embodiment 1 is modified to 30 parts of 2,2-bis(4-(meth)acryloxypolyethoxy)phenylpropane, 5 parts of nonylphenoxytetraethylene oxide acrylate, and 7 parts of polyurethane acrylic resin.

Example 5

The difference between this embodiment and embodiment 1 is that the mass fraction of the photopolymerization initiator in embodiment 1 is adjusted to 3 parts, including 0.5 parts of carbazole acridine compound and 2.5 parts of 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole.

Example 6

The difference between this embodiment and embodiment 1 is that the mass fraction of the photopolymerization initiator in embodiment 1 is adjusted to 4.2 parts, including 0.2 parts of carbazole acridine compounds and 4 parts of 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole.

Example 7

The difference between this embodiment and the embodiment 1 is that the photopolymerization initiator 3-(9-acridinyl)-carbazole in the embodiment 1 is replaced by N-ethyl-3-(9-acridinyl)-carbazole.

Comparative Example 1

The only difference between this comparative example and Example 1 is that the photopolymerization initiator does not contain a carbazole-based acridine compound, and the mass fraction of the sensitizer is adjusted to 0.2 parts.

Comparative Example 2

The only difference between this comparative example and Example 1 is that the carbazole-based acridine compound and 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole in the photopolymerization initiator are replaced by 0.3 parts by mass of 9-phenylacridine, and at the same time, the mass fraction of the sensitizer is adjusted to 0.2 parts.

Comparative Example 3

The only difference between this comparative example and Example 1 is that the carbazole-based acridine compound and 2,2'-di(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole in the photopolymerization initiator are replaced by 0.5 parts by mass of 9-phenylacridine, and at the same time, the mass fraction of the sensitizer is adjusted to 0.2 parts.

Comparative Example 4

The only difference between this comparative example and Example 1 is that the carbazole-based acridine compound and 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole in the photopolymerization initiator are replaced by 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole and 0.3 parts by mass of 9-phenylacridine, and at the same time, the mass fraction of the sensitizer is adjusted to 0.5 parts.

Comparative Example 5

The only difference between this comparative example and Example 1 is that the mass fraction of the sensitizer is adjusted to 0.1 part.

The amounts of the components used in the examples and comparative examples are summarized in Table 1.

Table 1 Composition of Examples 1-6 and Comparative Examples 1-5 (in parts by mass)

in:

A1: alkali-soluble resin; composed of methacrylic acid, 2-methyl-2-methyl methyl acrylate, 2-ethyl acrylate, 2-ethylhexyl acrylate = 20/50/20/13 (weight ratio), its average molecular weight = 90000, acid value 130mgKOH/g, GPC measured weight average molecular weight = 90000g/mol, solid content 42.5%.

B1: 2,2-bis(4-(meth)acryloyloxypolyethoxy)phenylpropane (Miwon Specialty Chemical, M2101)

B2: Nonylphenoxytetraethylene oxide acrylate (Miwon Specialty Chemical, M2101)

B3: Trimethylolpropane ethoxylate triacrylate (Miwon Specialty Chemical, M2101)

B4: Polyurethane acrylic resin (Hunan Chuyuan New Materials Co., Ltd.)

C1:3-(9-Acridinyl)-carbazole

C1': N-ethyl-3-(9-acridinyl)-carbazole

C2: 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-diimidazole (Changzhou Qiangli Electronic Materials)

C3:9-phenylacridine (Changzhou Qiangli)

D1: Tetraethyl Michler's ketone (Shanghai Yuanye Biotechnology)

E1: Malachite Green

E2: Colorless crystal violet

Performance Testing

The photosensitive dry films prepared in the examples and comparative examples were tested by a contact LED exposure machine and a direct drawing exposure machine, specifically including:

1) Substrate pretreatment: Grind, degrease, pickle and wash the 18μm copper-thick substrate with a grinder to remove oil and rust stains on the surface of the substrate.

2) Film lamination: Use a film laminating machine to press the dry film onto the substrate (speed 1.0 m/min, temperature 105 degrees, pressure 1.0 MPa).

3) Testing:

ALight Sensitivity

The coated dry film is pressed onto the pre-treated copper substrate by a laminator to obtain a test substrate.

A 41-segment exposure ruler was placed on the above test substrate, and exposure was performed using an exposure machine with different energies set.

Remove the polyethylene terephthalate film, use a developer (30 degrees 1.0% sodium carbonate aqueous solution) to spray the test substrate, remove the unexposed part, and read the exposure scale. The energy segment number will be different for different exposure energies. In this experiment, the best energy segment for the dry film is set to 20 segments. The lower the energy used, the higher the light sensitivity.

B Adhesion

Design the line width and line spacing of 10:400-70/400 to expose the film, expose the experimental substrate (set the energy to 20 energy levels), develop and remove the unexposed part, observe with a 100x microscope, and define the minimum width of the effective line width as adhesion.

C Analysis

Design line width and line spacing of 1:1, expose films with different line widths, expose the experimental substrate (set the energy to 20 energy levels), develop and remove the unexposed parts, observe with a 100x microscope, and define the minimum width that forms an effective line spacing as the resolution.

D. Defilming: Design an exposure film with 5 50mm*45mm exposure patterns. Expose the entire surface of the experimental substrate (set the energy to 20 energy levels) and develop. According to the exposure pattern, cut the substrate into 5 small pieces, immerse the small pieces in 2.8% sodium hydroxide solution, record the time when the dry film falls off the substrate, and take the average value of the 5 small pieces as the defilming time.

E shape (mouse bite, inverted trapezoid): Design line width and line spacing 10:400-70/400 exposure film, expose the experimental substrate (set energy to 20 energy levels), develop and remove the unexposed part, observe the developed substrate through SEM, observe whether there are voids at the bottom of the dry film side wall, and whether the dry film shape is an inverted trapezoid.

F cover hole: Use a 1.6mm thick copper-clad laminate with 48 circular holes of 6mm diameter for lamination, and expose the experimental substrate (set the energy to 20 levels).

Taking into account the relatively thick dry film, it was left exposed to light for one day after lamination (the energy was set to 20 energy levels). (Because the dry film at the edge of the circular hole would become thinner more easily after one day after lamination, and thus more likely to break during development) and developed three times. The number of broken holes was observed and evaluated as the hole-covering breakage rate. The lower the hole-covering breakage rate, the better the hole-covering performance.

The above test results are summarized in Tables 2 and 3 below.

Table 2 Evaluation results of contact LED exposure machine

Table 3 Evaluation results of direct drawing exposure machine

As can be seen from the table above, Comparative Example 1 has good light sensitivity on a contact exposure machine without adding C1, but has too low light sensitivity on a direct drawing exposure machine. After adding sensitizer C1 to Examples 1-6, only a relatively low light energy needs to be absorbed to initiate photopolymerization, and both the light sensitivity and properties are good on a contact exposure machine and a direct drawing exposure machine.

In comparative example 2, C3 and D1 are used alone. The photosensitivity is very high and can be used on a direct drawing exposure machine. However, due to the small amount of initiator, insufficient curing occurs at the bottom of the dry film, and the adhesion between the dry film and the substrate is also deteriorated. When used on a contact exposure machine, serious poor resolution occurs due to insufficient absorbance. If the content of C3 is increased, referring to comparative example 3, although it can be used normally on a direct drawing exposure machine, it cannot be exposed normally on a contact exposure machine. In comparative example 4, a combination of C2, C3, and D1 is used. Although there is no obvious abnormality in the characteristics when used on a direct drawing machine, it still cannot solve the problem of bottom voids and characteristic degradation on a contact exposure machine. As can be seen from comparative example 5, the sensitizer D1 has a promoting effect on the adhesion of the dry film. Less sensitizer will reduce the effectiveness of light energy reaching the bottom, resulting in insufficient adhesion at the bottom.

It can be seen from Examples 1 and 3 that due to the special long-chain structure of B4, the hole covering performance can be enhanced. It can be seen from Examples 1 and 2 that B2 has good hydrophilicity, which allows the dry film to be well dissolved in the film removal liquid, thereby increasing the film removal performance. It can be seen from Examples 1 and 4 that B3 has a high functionality and can increase the cross-linking density. At the same time, due to its small molecule, it can well improve the bonding force between the dry film and the substrate, improve the insufficient bottom adhesion, and effectively improve the undesirable phenomenon of the dry film floating off. Therefore, using the combination of C1, C2, and D1, the dry film has good photosensitivity and good dry film adhesion, and there is no void at the bottom. It can be used in both direct-drawing exposure machines and contact exposure machines.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (9)

1. The photosensitive resin composition is characterized by comprising the following raw material components in parts by mass: 48-68 parts of alkali-soluble resin, 32-52 parts of photopolymerizable monomer with at least one ethylene unsaturated bond, 2.7-4.5 parts of photopolymerization initiator and 0.1-0.3 part of sensitizer; the sensitizer is tetraethyl ketone Mi;

the photopolymerization initiator comprises carbazolylacridine compounds shown in a formula (I) and 2,2 '-bis (2-chlorophenyl) -4,4',5 '-tetraphenyl-1, 2' -diimidazole; the mass ratio of the carbazolylacridine compound to the 2,2 '-bis (2-chlorophenyl) -4,4',5 '-tetraphenyl-1, 2' -diimidazole is 0.2-0.5:2.5-4;

Wherein R is one of alkyl, alkoxy, aryl and substituted aryl.

2. The photosensitive resin composition according to claim 1, wherein the photosensitive resin composition comprises the following raw material components in parts by mass: 48-58 parts of alkali-soluble resin, 32-42 parts of photopolymerisable monomer with at least one ethylene unsaturated bond, 3-3.85 parts of photopolymerization initiator and 0.15-0.2 part of sensitizer.

3. The photosensitive resin composition according to claim 1, wherein the mass ratio of the carbazolylacridine compound to 2,2 '-bis (2-chlorophenyl) -4,4',5 '-tetraphenyl-1, 2' -diimidazole is 0.35 to 0.5:3.5-4.

4. A photosensitive resin composition according to claim 3, wherein the carbazolylacridine compound 2,2 '-bis (2-chlorophenyl) -4,4',5 '-tetraphenyl-1, 2' -diimidazole has a mass ratio of 0.35:3.5.

5. The photosensitive resin composition according to claim 1, wherein the carbazolylacridine compound 2,2 '-bis (2-chlorophenyl) -4,4',5 '-tetraphenyl-1, 2' -diimidazole has a mass ratio of 0.5:2.5.

6. The photosensitive resin composition according to claim 1, wherein the carbazolylacridine compound comprises any one of 3- (9-acridinyl) -carbazole, N-ethyl-3- (9-acridinyl) -carbazole, N-ethoxy-3- (9-acridinyl) -carbazole, N-phenyl-3- (9-acridinyl) -carbazole, and N-chlorophenyl-3- (9-acridinyl) -carbazole.

7. The photosensitive resin composition according to claim 1, wherein the photopolymerizable monomer having at least one ethylenic unsaturated bond comprises at least three of 2, 2-bis (4- (meth) acryloxypolyethoxy) phenylpropane, nonylphenoxy tetraethyleneoxy acrylate, trimethylol propane ethyleneoxy triacrylate, or urethane propylene resin.

8. The photosensitive resin composition according to claim 1, further comprising 0.1 to 1 parts by mass of an additive comprising malachite green and/or leuco crystal violet.

9. A photosensitive dry film, comprising a substrate layer, a photosensitive material layer and a protective film layer, wherein the photosensitive material layer is the photosensitive resin composition according to any one of claims 1 to 8.