Dual-curing 3D printing photoresist and application thereof

Abstract

The invention relates to the technical field of photoresist, in particular to dual-curing 3D printing photoresist and application thereof. The dual-curing 3D printing photoresist comprises the following raw materials in parts by weight: 1-3 parts of an epoxy curing agent, 0.1-2 parts of an acrylic monomer, 3-5 parts of acrylic resin, 1-5 parts of epoxy resin, 0-2 parts of a photoinitiator, 0-1 part of a thermal initiator and 0-2 parts of a coupling agent. According to the dual-curing 3D printing photoresist provided by the invention, dual curing is realized by adjusting the ratio of the epoxy resin system to the acrylic acid system in a photoresist formula, and the dual-curing 3D printing photoresist can be used for preparing special-shaped bent optical waveguides needing suspension processing through a two-photon micro-nano processing technology; and secondary coating is not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of photoresists, and in particular to a dual-curing 3D printing photoresist and applications thereof. Background Art

[0002] Photoresist, also known as photoresist, refers to a thin film material that changes its solubility when exposed to ultraviolet light, electron beam, ion beam, X-ray, etc. In the process of preparing photoresist, after the coating is exposed and developed, the exposed part is dissolved and the unexposed part remains. Photoresist is often used in the preparation of optical waveguides.

[0003] Optical waveguide refers to a structure that can guide and transmit light waves. It has excellent optical properties and is widely used in optical communications and optoelectronics. Optical fiber is a type of optical waveguide. Optical fiber is composed of two layers of materials with different refractive indices. The inner layer is a core with extremely high transparency, and the outer layer of the core is a cladding. Generally, the refractive index of the core is 1% greater than that of the cladding. According to the principle of refraction and total reflection of light, when the angle at which light hits the interface between the core and the cladding is greater than the critical angle for total reflection, the light cannot pass through the interface and is completely reflected.

[0004] The main raw material of existing 3D printable optical waveguides is acrylic polyester, and then its outer layer is coated with a layer of low refractive index resin, such as epoxy resin or polyurethane. There are two problems in the preparation of optical waveguides: first, at least two steps are required in the processing process, that is, the optical waveguide needs to be coated twice after the core is prepared, which is cumbersome and affects the processing efficiency; second, for some special-shaped curved optical waveguides that need to be overhanging, the requirements for photoresist and processing technology are extremely high, and it is difficult to achieve mass production. Summary of the invention

[0005] In view of the technical problems that the preparation of 3D printable optical waveguides in the prior art, especially the preparation of special-shaped curved optical waveguides that require overhang processing, requires secondary coating treatment, has complicated processes and high requirements, and is limited in batch and large-scale production, the present invention provides a dual-cured 3D printing photoresist and its application. By adjusting the ratio of the two systems of epoxy resin system (epoxy resin, epoxy curing agent and thermal initiator) and acrylic system (acrylic monomer, acrylic resin and photoinitiator) in the photoresist formula, the photoresist can achieve dual curing without the need for secondary coating, and through two-photon micro-nano processing technology, the dual-cured 3D printing photoresist can be used to prepare special-shaped curved optical waveguides that require overhang processing.

[0006] In a first aspect, the present invention provides a dual-curing 3D printing photoresist, which comprises the following raw materials, by weight: 1-3 parts of epoxy curing agent, 0.1-2 parts of acrylic monomer, 3-5 parts of acrylic resin, 1-5 parts of epoxy resin, 0-2 parts of photoinitiator, 0-1 parts of thermal initiator and 0-2 parts of coupling agent; The epoxy curing agent is selected from at least one of 2-ethyl-4-methylimidazole and pentaerythritol tetra-3-mercaptopropionate; the acrylic monomer is selected from at least one of tricyclodecane dimethanol diacrylate, isobornyl acrylate and tetrahydrofuran acrylate; the acrylic resin is selected from polyurethane acrylic resin, epoxy acrylic resin, 2-chlorostyrene, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4 -Heptafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, methacrylic acid pentabromophenyl acrylate, pentabromophenyl acrylate, pentabromobenzyl methacrylate, pentabromobenzyl acrylate, vinylphenyl sulfate, 1-naphthyl methacrylate, 2-vinylthiophene, 2,6-dichlorostyrene, N-vinylphthalimide, 2-chlorostyrene, zirconium acrylate, carboxyethyl zirconium acrylate, hafnium carboxyethyl acrylate, bromonorbornane lactone triacrylate zirconium carboxylate, o-phenylphenoxyethyl acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene and 9-anthracenylmethyl methacrylate At least one of; the epoxy resin is selected from at least one of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, alicyclic epoxy resin and phenolic epoxy resin; the photoinitiator is selected from at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin diethyl ether, 1-hydroxycyclohexyl phenyl ketone and diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide; the thermal initiator includes bis(4-diphenylthiophenyl) sulfide dihexafluoroantimonate; the coupling agent includes Y-glycidyl ether oxygen propyl trimethoxy silane.

[0007] Further, the dual-curing 3D printing photoresist includes the following raw materials, by weight: 1.1-1.2 parts of epoxy curing agent, 1-2 parts of acrylic monomer, 3.5-4.5 parts of acrylic resin, 3-3.5 parts of epoxy resin, 0.1-2 parts of photoinitiator, 0-0.5 parts of thermal initiator and 0-0.1 parts of coupling agent; Among them, the epoxy curing agent is selected from at least one of 2-ethyl-4-methylimidazole and pentaerythritol tetrakis-3-mercaptopropionate; the acrylic monomer is tricyclodecane dimethanol diacrylate; the acrylic resin is selected from at least one of polyurethane acrylic resin, epoxy acrylic resin and 2-chlorostyrene; the epoxy resin is selected from at least one of bisphenol A type epoxy resin and hydrogenated bisphenol A epoxy resin; the photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide; the thermal initiator is di(4-diphenylthiophenyl) sulfide dihexafluoroantimonate; and the coupling agent is Y-glycidyloxypropyltrimethoxysilane.

[0008] Further, the dual-curing 3D printing photoresist includes the following raw materials, measured by weight: 1.1-1.2 parts of epoxy curing agent, 1-2 parts of acrylic monomer, 3.5-4 parts of acrylic resin, 3-3.5 parts of epoxy resin, 0.1-1 parts of photoinitiator and 0-0.1 parts of thermal initiator; Among them, the epoxy curing agent is 2-ethyl-4-methylimidazole and pentaerythritol tetrakis-3-mercaptopropionate, the acrylic monomer is tricyclodecane dimethanol diacrylate, the acrylic resin is polyurethane acrylic resin and epoxy acrylic resin, the epoxy resin is bisphenol A type epoxy resin, the photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, and the thermal initiator is di(4-diphenylthiophenyl) sulfide dihexafluoroantimonate.

[0009] Furthermore, the mass ratio of 2-ethyl-4-methylimidazole to pentaerythritol tetrakis-3-mercaptopropionate is 0.1-0.2:1.

[0010] Furthermore, the mass ratio of the polyurethane acrylic resin to the epoxy acrylic resin is 3:0.5-1.

[0011] In a second aspect, the present invention provides a dual-curing 3D printing photoresist and its application in the preparation of optical waveguides.

[0012] Furthermore, dual-cured 3D printed photoresist is used to prepare optical waveguides through two-photon micro-nano processing technology.

[0013] Furthermore, the optical waveguide is an optical fiber.

[0014] The beneficial effects of the present invention are: The present invention provides a dual-curing 3D printing photoresist. The addition of a photoinitiator in the raw material can form an interpenetrating network between epoxy resin and acrylic resin. The processed structure has a denser cross-linking density, which improves the reaction activity. The refractive index difference of the optical waveguide prepared subsequently is adjusted by adjusting the ratio of each raw material within a certain range to achieve total reflection. In the process of preparing the optical waveguide, the dual-curing 3D printing photoresist does not require secondary coating and development. Through photocuring and thermal curing, a special-shaped curved optical waveguide that requires overhang processing can be prepared. The two-photon micro-nano processing technology realizes the microstructure processing with a line width of less than 70nm, which broadens the application field of the optical waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is an optical photograph of the waveguide structure processed on the end face of an optical fiber.

[0017] Figure 2 This is a SEM photograph of the line width of the optical fiber prepared by the dual-curing 3D printing photoresist in Example 2. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0019] The embodiment of the present invention adopts the following method to prepare dual-curing 3D printing photoresist: Under a yellow light, a certain ratio of acrylic monomer, acrylic resin, epoxy resin, photoinitiator, thermal initiator and coupling agent were heated and stirred in a brown reagent bottle until completely dissolved. The heating temperature was 50°C. After cooling to room temperature, a certain proportion of epoxy curing agent was added and slowly stirred at room temperature until fully mixed. After filtering, a dual-curing 3D printing photoresist was obtained and stored at -20°C for later use.

[0020] Table 1 Components and ratios of dual-curing 3D printing photoresist formulations for Examples 1-5

[0021] Note: Epoxy acrylic resin is both an epoxy resin and an acrylic resin, and has both light curing and heat curing properties. It should be used as the measured portion of acrylic resin in formula mixing.

[0022] The dual-cured 3D printing photoresist obtained in Example 2 uses two-photon micro-nano processing technology to prepare optical fibers without coating and development. Specifically, an MJ-Works device with a dual-wavelength femtosecond laser system (manufacturer: Yantai Moji Nanotechnology Co., Ltd.) is used and operated according to its instruction manual: Method 1: Dual-cured 3D printed photoresist is dripped into the mold and placed in an 80°C oven for 2 hours for thermal curing. Its physical state changes from liquid to solid. Then the solid dual-cured 3D printed photoresist is placed in the MJ-Works device and photocured in a non-dipping mode. The solid dual-cured 3D printed photoresist is processed by 3D trajectory through spot focusing and scanning. The processed structural part is regarded as the core, and the unprocessed part is regarded as the outer skin cladding. The core structure is clearly visible during the processing. After the processing, post-processing is performed and full exposure with a mercury lamp is used to eliminate its photosensitivity to obtain an optical fiber.

[0023] Because the degree of polymerization of the fiber core is greater than that of the outer cladding, the refractive index of the fiber core is greater than that of the outer cladding. Through the difference in refractive index between the fiber core and the outer cladding, total reflection is achieved. Moreover, the optical fiber obtained by two-photon micro-nano processing technology can be a suspended optical fiber structure of any shape. Full exposure to mercury lamp can make the structure stable, transparent, and non-yellowing, and can be used for a long time. Figure 1 .

[0024] Method 2: Dual-curing 3D printed photoresist is dropped into the substrate, placed in the MJ-Works equipment, and light-cured in the dip mode. The fiber core is obtained by 3D trajectory processing inside the liquid dual-curing 3D printed photoresist through spot focusing and scanning, which can achieve microstructure processing with a line width of 68.89nm (see Figure 2 ), after the fiber core structure is processed, there is no need for development and coating. It is directly placed in an oven at 80℃ for 2 hours to obtain a solid outer cladding, and then fully exposed to a mercury lamp to obtain an optical fiber.

[0025] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A dual-curing 3D printing photoresist, It is characterized in that The dual-curing 3D printing photoresist includes the following raw materials by weight: 1-3 parts of epoxy curing agent, 0.1-2 parts of acrylic monomer, 3-5 parts of acrylic resin, 1-5 parts of epoxy resin, 0-2 parts of photoinitiator, 0-1 parts of thermal initiator and 0-2 parts of coupling agent; The epoxy curing agent is selected from at least one of 2-ethyl-4-methylimidazole and pentaerythritol tetra-3-mercaptopropionate; the acrylic monomer is selected from at least one of tricyclodecane dimethanol diacrylate, isobornyl acrylate and tetrahydrofuran acrylate; the acrylic resin is selected from polyurethane acrylic resin, epoxy acrylic resin, 2-chlorostyrene, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 2,2,3,3,4,4,4-heptafluorobutyl acrylate, 2,2,3,3,4,4,4 -Heptafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 1,1,1,3,3,3-hexafluoroisopropyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, methacrylic acid pentabromophenyl acrylate, pentabromophenyl acrylate, pentabromobenzyl methacrylate, pentabromobenzyl acrylate, vinylphenyl sulfate, 1-naphthyl methacrylate, 2-vinylthiophene, 2,6-dichlorostyrene, N-vinylphthalimide, 2-chlorostyrene, zirconium acrylate, carboxyethyl zirconium acrylate, hafnium carboxyethyl acrylate, bromonorbornane lactone triacrylate zirconium carboxylate, o-phenylphenoxyethyl acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene and 9-anthracenylmethyl methacrylate At least one of; the epoxy resin is selected from at least one of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, alicyclic epoxy resin and phenolic epoxy resin; the photoinitiator is selected from at least one of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin diethyl ether, 1-hydroxycyclohexyl phenyl ketone and diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide; the thermal initiator includes bis(4-diphenylthiophenyl) sulfide dihexafluoroantimonate; the coupling agent includes Y-glycidyl ether oxygen propyl trimethoxy silane.

2. A dual-curing 3D printing photoresist as claimed in claim 1, It is characterized in that The dual-curing 3D printing photoresist includes the following raw materials by weight: 1.1-1.2 parts of epoxy curing agent, 1-2 parts of acrylic monomer, 3.5-4.5 parts of acrylic resin, 3-3.5 parts of epoxy resin, 0.1-2 parts of photoinitiator, 0-0.5 parts of thermal initiator and 0-0.1 parts of coupling agent; Among them, the epoxy curing agent is selected from at least one of 2-ethyl-4-methylimidazole and pentaerythritol tetrakis-3-mercaptopropionate; the acrylic monomer is tricyclodecane dimethanol diacrylate; the acrylic resin is selected from at least one of polyurethane acrylic resin, epoxy acrylic resin and 2-chlorostyrene; the epoxy resin is selected from at least one of bisphenol A type epoxy resin and hydrogenated bisphenol A epoxy resin; the photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide; the thermal initiator is di(4-diphenylthiophenyl) sulfide dihexafluoroantimonate; and the coupling agent is Y-glycidyloxypropyltrimethoxysilane.

3. A dual-curing 3D printing photoresist as claimed in claim 1 or 2, It is characterized in that The dual-curing 3D printing photoresist includes the following raw materials by weight: 1.1-1.2 parts of epoxy curing agent, 1-2 parts of acrylic monomer, 3.5-4 parts of acrylic resin, 3-3.5 parts of epoxy resin, 0.1-1 parts of photoinitiator and 0-0.1 parts of thermal initiator; Among them, the epoxy curing agent is 2-ethyl-4-methylimidazole and pentaerythritol tetrakis-3-mercaptopropionate, the acrylic monomer is tricyclodecane dimethanol diacrylate, the acrylic resin is polyurethane acrylic resin and epoxy acrylic resin, the epoxy resin is bisphenol A type epoxy resin, the photoinitiator is diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, and the thermal initiator is di(4-diphenylthiophenyl) sulfide dihexafluoroantimonate.

4. A dual-curing 3D printing photoresist as claimed in claim 3, It is characterized in that The mass ratio of 2-ethyl-4-methylimidazole to pentaerythritol tetrakis-3-mercaptopropionate is 0.1-0.2:

1.

5. A dual-curing 3D printing photoresist as claimed in claim 3, It is characterized in that The mass ratio of polyurethane acrylic resin to epoxy acrylic resin is 3:0.5-1.

6. Use of the dual-curing 3D printing photoresist as claimed in claim 1 in preparing an optical waveguide.

7. The use according to claim 6, It is characterized in that Dual-curing 3D printed photoresist is used to prepare optical waveguides through two-photon micro-nano processing technology.

8. The use according to claim 6 or 7, It is characterized in that The optical waveguide is an optical fiber.

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