Novel high-sensitivity photoinitiator mixtures suitable for long-wavelength low-energy curing

Abstract

The invention relates to the field of photocuring new material chemicals, in particular to composition of a novel photoinitiator mixture system, application of the novel photoinitiator mixture system as a photoinitiator in an ethylenically-bond-containing unsaturated radiation polymerization system and the ethylenically-bond-containing unsaturated radiation polymerization system containing the photoinitiator mixture component. The novel photoinitiator mixture system disclosed by the invention is widely suitable for emerging long-wavelength high-photosensitivity low-energy curing application scenes represented by high-end PCB (Printed Circuit Board) photoresist.

Description

[Technical Field]

[0001] This invention relates to the field of photocurable new materials chemicals, and particularly to the composition of a novel photoinitiator mixture system, its use as a photoinitiator in radiation-resistant polymer systems containing olefin-bonded unsaturated components, and radiation-resistant polymer systems containing olefin-bonded unsaturated components of this photoinitiator mixture. The novel photoinitiator mixture system disclosed in this invention is widely suitable for emerging long-wavelength, high-photosensitivity, low-energy curing applications, exemplified by high-end PCB photoresists. [Background Technology]

[0002] Photoinitiators are key materials that absorb energy from radiation sources and / or electron beams to generate polymerization initiating species such as active free radicals or cationic acids. They are crucial functional chemicals in the field of photocuring (radiation) materials technology. In recent years, with the strong promotion of national carbon neutrality, energy conservation, and emission reduction laws and regulations, the photocuring industry has undergone a rapid upgrade and transformation from short-wavelength, high-energy curing to long-wavelength, low-energy curing. The prominent low-energy curing is exemplified by emerging applications such as long-wavelength LEDs or laser light sources. This transformation has created an increasingly urgent demand for improved photosensitivity of photoinitiators, indicating a continuous need for technological innovation in the industry: the research and industrialization of new photoinitiator substances capable of addressing a variety of comprehensive application requirements, including improved photopolymerization performance, low-cost economic competitiveness, ease of use, and environmental and health friendliness.

[0003] In the field of PCB photoresists and high-pigment-concentration photocurable new materials, typical systems such as PCB dry film, PCB wet film, CO2 laser direct writing LDI process, and high carbon black pigment content formulations urgently need to be researched and discovered in the 300-450 nm range, especially in the 395-420 nm range, under low-energy long-wavelength radiation curing light sources. There is an urgent need to research and discover new photoinitiator solutions with high photosensitivity, high (solubility) formulation applicability, and low cost competitiveness. [Summary of the Invention]

[0004] This application, through extensive molecular design and screening matching, discovered that the diastereomeric oxime ester compound shown in structural formula A (a commercially available product from Shenzhen Youwei Technology Holding Group Co., Ltd., China, under the brand name APi-1206) and N-phenylglycine (NPG) shown in structural formula B, unexpectedly provide an ideal solution for long-wavelength, low-energy, high-sensitivity curing. This solution demonstrates excellent long-wavelength (300-450 nm) low-energy photosensitivity, high solubility and formulation compatibility, as well as outstanding cost reduction and efficiency improvement performance.

[0005] While the photosensitivity of photoinitiators is a common understanding among industry professionals, high solubility is a crucial yet easily overlooked property. Prominent examples include the commonly used arylimidazolium (BCIM) type photoinitiators and alkoxyanthracene (DBA) type co-initiators in PCB dry film systems. These two types of substances have limited photosensitivity (thus usually requiring the addition of other initiators), and, disliked by customers, their poor solubility necessitates the use of substantial amounts of solvent to promote dispersion and dissolution in the formulation system, a costly and unsafe process.

[0006]

[0007] The photoinitiator mixture is characterized in that, based on 100% of its total mass, it contains a percentage by mass of photoinitiator A, b percentage by mass of photoinitiator B, and c percentage by mass of additives, subject to the following constraints:

[0008] (1) The sum of a, b, and c is 100% by mass.

[0009] (2) The values ​​of a and b are not zero.

[0010] The c percentage by weight of the additive is at least one of photoinitiators, olefin-containing monomers, olefin-containing resins, or functional additives known in other literature.

[0011] The “document-known photoinitiator” is any one of the following photoinitiator compounds or any mixture of two or more photoinitiator compounds: including aryl imidazole (BCIM) type, alkoxyanthracene (DBA) type, hydroxyketone type, aminoketone type, phosphonophosphate type, oxime ester type, benzophenone type, phenylglyoxylate type, thioxanthones, onium salt cationic photoinitiators (Sulfoniums or Iodoniums or Photo-Acid Generators, i.e., so-called PAGs), or photoinitiator substances in which dyes act as substantial photosensitizers.Examples of photoinitiators include Darocur 1173, Irgacure 184, APi-180 (Shenzhen Youwei Technology Holding Group Co., Ltd.), APi-307 (Shenzhen Youwei Technology Holding Group Co., Ltd.), APi-308 (Shenzhen Youwei Technology Holding Group Co., Ltd.), APi-1207 (Shenzhen Youwei Technology Holding Group Co., Ltd.), Irgacure 2959, Irgacure MBF, Irgacure 127, Irgacure 651, Esacure KIP-150, Esacure KIP-160, Esacure KIP-1001, Esacure 01, Irgacure 907, Irgacure 500, Irgacure 2200, Irgacure 2022, Irgacure 4500, Irgacure 369, and Irgacure... 379, Irgacure 819, Irgacure TPO, Irgacure TPO-L, BP, Methyl or Ethyl Michalcone, Esacure TZT, Irgacure 754, Irgacure ITX, Irgacure DETX, Irgacure CPTX, Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03, Irgacure OXE-03, Tronly304 (Changzhou Qiangli Electronic New Materials Co., Ltd.), Tronly 305 (Changzhou Qiangli Electronic New Materials Co., Ltd.), Irgacure 250, ADEKANCI-831 (ADEKAN Corporation, Japan), ADEKAN-1414 (ADEKAN Corporation, Japan), Irgacure 290, Irgacure 270, and coumarin-type dye photosensitizers, etc.; the above system also includes corresponding co-initiators, such as active amines and / or hydrosilane-type active hydrogen donor co-initiators.

[0012] The olefin-containing (C=C) monomer is any polymerizable unsaturated compound containing an olefin bond, including but not limited to (meth)acrylate, olefins, conjugated dienes, styrene, maleic anhydride, fumaric anhydride, vinyl acetate, vinylpyrrolidone, vinylimidazole, (meth)acrylate, (meth)acrylate derivatives such as (meth)acrylamide, vinyl halides, vinylidene halides, etc.

[0013] The olefin-containing (C=C) resin is any olefin-containing prepolymer and oligomer, including but not limited to (meth)acrylamide functional (meth)acrylic acid copolymers, polyurethane formate (meth)acrylates, polyester (meth)acrylates, unsaturated polyesters, polyether (meth)acrylates, siloxane (meth)acrylates, epoxy resin (meth)acrylates, and water-soluble or water-dispersible derivatives of the above substances.

[0014] The functional additives are various additives, including, but not limited to, polymerization inhibitors, active amine co-initiators, leveling agents, defoamers, anti-sagging agents, thickeners, viscous agents, dispersants, antistatic agents, solubilizers, diluents, water or organic solvents, antibacterial agents, flame retardants, inorganic or organic fillers (e.g., nano-alumina, silica, calcium carbonate, barium sulfate, etc.) and / or colorants (e.g., pigments or dyes, etc.), UV absorbers and / or light stabilizers that enhance the weather resistance of coatings and inks, and suitable aqueous dispersions or water-soluble products of the above components.

[0015] We also disclose a new type of radiation-cured material formulation system, characterized by:

[0016] (1) Contains at least one of the [a+b+c] type photoinitiator mixtures disclosed in this invention;

[0017] (2) Contains at least one olefinic (C=C) unsaturated compound (monomer or resin).

[0018] Preferably, the amount of "at least one photoinitiator mixture disclosed in this invention" in the formulation system is 0.001-20%, more preferably 0.01-10%.

[0019] Preferably, the formulation system contains photoinitiator substances known in other literature.

[0020] The novel radiation-curing material formulation system disclosed in this invention includes photocurable coatings or inks, which have broad application value in markets such as PCB photoresist inks, laser direct imaging (LDI) inks, printing and packaging inks, wooden furniture, plastic products, printing and packaging, inkjet printing, consumer electronics, motor vehicle interior and exterior trim, pipe profiles, industrial flooring, building curtain walls, or 3D printing additive manufacturing.

[0021] The essence of the invention will be further illustrated in the embodiments.

Detailed Implementation Methods

[0022] Example:

[0023] A sample of a radiation-curable PCB solder resist ink material system containing olefin bonds was prepared according to the following formulation (by weight percentage): Component A: o-cresyl aldehyde epoxy acrylate oligomer: 55%; DBE solvent: 20%; photoinitiator: 3.5% (or other specified amount); silica: 1.5%; barium sulfate: 12%; titanium dioxide: 8%; Component B: DPHA acrylate monomer: 35%; epoxy resin: 35%; DBE solvent: 20%; barium sulfate: 10%. The above materials were mixed and added to a dispersion tank, dispersed using a high-speed disperser, and then milled five times using a hydraulic three-roll mill. After filtration using a cartridge filter, the resulting ink was printed onto the PCB board using an inkjet printer equipped with an XAAR printhead at a speed of 80 m / min. The power of the 395 nm LED curing light source was approximately 8 W / cm². 2 The photoinitiation activity was quantized using a Stouffer-type exposure standard 21-level grayscale scale. When the photoinitiator was 2.5% Irgacure 907 and 1% ITX, the exposure grayscale was 6 levels; when the above photoinitiator was replaced with 0.2% APi-1206(A) and 0.1% NPG(B), despite a significant reduction in dosage, the exposure grayscale reached 14 levels. This example demonstrates that using the photoinitiator disclosed in this invention can significantly improve photosensitivity.

[0024] Example:

[0025] The radiation-curable ink material system containing olefin bonds was prepared according to the following formula (by weight percentage): o-cresyl aldehyde epoxy acrylate oligomer: 55%; TMPTA acrylate monomer: 25%; photoinitiator: 4.0%; phthalocyanine blue pigment: 1.5%; talc: 14%; leveling agent: 0.5%. The ink thickness after coating was approximately 15 micrometers. After baking at 80 degrees Celsius for half an hour, it was exposed using a 405 nm wavelength carbon dioxide laser on a conveyor belt exposure machine. After alkaline development, the required mJ / cm² exposure was tested. 2 The energy level was used to evaluate the initiation activity of the photoinitiator. When the photoinitiator was 3.5% Irgacure 907 and 0.5% ITX, the exposure requirement was 180 mJ / cm². 2 When the photoinitiator was replaced with 0.3% APi-1206(A) and 0.1% NPG(B), the exposure requirement was only 80 mJ / cm², despite a significant reduction in dosage. 2 This embodiment demonstrates that using the photoinitiator disclosed in this invention can significantly reduce the energy required for exposure and improve photosensitivity.

[0026] Example:

[0027] The olefin-containing radiation-curable PCB dry film photosensitive material system sample was prepared according to the following formula (by weight percentage): alkali-soluble resin (Shenzhen Youwei Technology Holding Group Co., Ltd.): 53%; phenolic ring-modified acrylate monomer (Shenzhen Youwei Technology Holding Group Co., Ltd.): 5%; bisphenol A acetylated diacrylate monomer: 36%; photoinitiator: 4%; additives (containing brilliant green pigment and leuco crystal violet): 2%. The copper-clad laminate was polished using a grinding machine, washed with water, and dried to obtain a bright and fresh surface. The laminating machine's pressure roller temperature was set to 110℃, the conveying speed to 1.0m / min, and heat lamination was performed under standard pressure. After lamination, the sample was LDI exposed using a Japanese Adtec IP-6 exposure machine (wavelength 405 nm); photosensitivity testing was conducted using a Stouffer 41-step exposure scale, with the exposure count controlled between 13 and 17 divisions. After exposure, the sample was developed at 30°C using a 1% sodium carbonate aqueous solution. It then underwent standard evaluation procedures including heat curing, electroplating, lamination, and etching. When the photoinitiator was 3.5% BCIM (arylimidazolium) and 0.5% DBA (dibutoxyanthracene), the exposure grayscale was 13 levels. When the photoinitiator was replaced with 0.2% APi-1206(A), 0.1% NPG(B), and 1% BCIM, despite a significant reduction in total dosage, the exposure grayscale reached 17 levels. This example demonstrates that using the photoinitiator disclosed in this invention can significantly improve photosensitivity and exposure resolution.

[0028] It should be emphasized that the above embodiments are merely exemplary and not limiting. Based on the disclosure of this application, any adjustments or changes to the reaction conditions or parameters that a person skilled in the art might normally adopt will not deviate from the spirit of the invention. The scope of protection of this patent shall be determined by the relevant claims.

Claims

1. A mixture of highly sensitive photoinitiators suitable for long-wavelength (300-450 nm) low-energy radiation curing, characterized in that... Contains a percentage by mass of diastereomeric oxime compound A, b percentage by mass of phenylglycine compound B, and / or c percentage by mass of additives; The constraints are: (1) The sum of a, b, and c is 100% by mass. (2) The values ​​of a and b are not zero. The c percentage by weight of the additive is at least one of the following known in other literature: photoinitiator, olefin-containing (C=C) monomer, olefin-containing resin, or functional additive.

2. Use of the mixture described in claim 1 as a photoinitiator for radiation-initiated systems containing olefinic (C=C) unsaturated polymerizable systems.

3. A novel radiation-curable material formulation system, characterized by: (1) Contains at least one of the [a+b+c] type photoinitiator mixtures disclosed in claim 1; (2) Contains at least one olefinic (C=C) unsaturated compound (monomer or resin).

4. According to claim 1, the "known photoinitiator" is any one of the following photoinitiator compounds or any mixture of two or more photoinitiator compounds: including aryl imidazole (BCIM) type, alkoxyanthracene (DBA) type, hydroxyketone type, aminoketone type, phosphonophosphate type, oxime ester type, benzophenone type, phenylglyoxylate type, thioxanthones, onium salt cationic photoinitiators (Sulfoniums or Iodoniums or Photo-Acid Generators, i.e., so-called PAGs), or photoinitiator substances in which dyes act as substantial photosensitizers.

5. According to claims 1-3, preferably, the amount of the photoinitiator mixture added to the radiation-curable new material formulation system is 0.001-20%, more preferably 0.01-10%.

6. According to claim 3, the novel radiation-curable new material formulation system is used as a photocurable coating and ink; preferably, it is used as a PCB photoresist ink, laser direct imaging (LDI) ink, or printing and packaging ink.

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