High-strength and high-toughness photocuring material as well as preparation method and application thereof

Abstract

The invention relates to a high-strength and high-toughness photocuring material as well as a preparation method and application thereof. The high-strength and high-toughness photocuring material comprises phenolic resin modified polyurethane acrylate (oligomer 1), dimer acid diisocyanate-based polyurethane acrylate (oligomer 2), a monofunctional diluent, a photoinitiator and other auxiliaries. Through the rigidity-flexibility collaborative design of the oligomer 1 and the long-chain alkyl reinforcing effect of the oligomer 2, the tensile strength (47-55MPa) and notch impact strength (15-19KJ / m) of the material are remarkably improved, and the material is suitable for 3D printing of precise structural parts such as glasses frames and the like. By optimizing the structural design and formula combination of the oligomer, the problem of insufficient mechanical properties of the existing photosensitive resin is solved, and the photosensitive resin is particularly suitable for 3D printing of glasses frames.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable materials, and in particular to a high-strength and high-toughness photocurable material and a preparation method and application thereof. Background Art

[0002] Photocuring 3D printing technology has developed rapidly in recent years. It has the characteristics of low cost, fast molding and high precision. It has been widely used in many fields in recent years. 3D printing photosensitive resins generally include oligomers, reactive diluents, photoinitiators and various additives. The oligomers used in photocuring products are the most important components of photosensitive resins and the main factors affecting the performance of the material after curing. They refer to photosensitive resins with various unsaturated double bonds or epoxy groups that can undergo photocuring reactions, low molecular weight and free radical polymerization.

[0003] 3D printing can be used for the application of eyeglass frames, but the performance of existing photosensitive resins is relatively poor. The mechanical properties of existing photosensitive resins are insufficient, especially the low strength and toughness, which makes the material easy to deform and crack after curing, making it difficult to meet the needs of long-term use scenarios such as eyeglass frames.

[0004] In the prior art, the oligomer system of photosensitive resin mostly adopts conventional polyurethane acrylate or epoxy resin, and its molecular chain structure design has limited synergistic improvement on toughness and strength, which restricts the application of photocuring technology in precision structural parts and becomes a major constraint on the development of photocuring technology in the eyewear industry. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a high-strength and high-toughness photocurable material and a preparation method and application thereof, which solves the problem of insufficient mechanical properties of existing photosensitive resins by optimizing the oligomer structure design and formula combination, and is particularly suitable for 3D printing eyeglass frames.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions: A high-strength and high-toughness photocurable material, comprising the following components by weight: Oligomer 1: 10-40 parts; Oligomer 2: 10-40 parts; Monofunctional diluent: 10-20 parts, selected from acrylate monomers with Tg of 90-200°C; Photoinitiator: 1-3 parts; Other additives: 1-3 parts.

[0007] As a further technical solution of the present invention: the oligomer 1 is a phenolic resin modified polyurethane acrylate, which is prepared by ring-opening polymerization of linear phenolic resin and alkylene oxide and then capped with isocyanoethyl methacrylate.

[0008] As a further technical solution of the present invention: the oligomer 2 is a polyurethane acrylate obtained by reacting dimer acid diisocyanate with polytetramethylene ether diol and capping with HEMA.

[0009] As a further technical solution of the present invention: the monofunctional diluent is selected from at least one of dicyclopentanyl methacrylate, isobornyl methacrylate, trimethylcyclohexyl acrylate and acryloyl morpholine.

[0010] As a further technical solution of the present invention: the other auxiliary agents include at least one of an antioxidant, a light stabilizer, a UV color paste, and an inorganic additive.

[0011] As a further technical solution of the present invention: the preparation method of the oligomer 1 comprises the following steps: Step a1: using 1 mol of a linear phenolic resin with a functionality of 2-4 as an initiator, and subjecting it to ring-opening polymerization with 2-30 mol of an alkylene oxide (at least one of ethylene oxide, propylene oxide or butylene oxide) under KOH catalysis, and obtaining a linear phenolic resin modified polyether after neutralization; Among them, linear phenolic resin is formed by the condensation of phenol and aldehyde compounds. Due to the differences between phenol and aldehyde materials, phenolic resins with different structures can be produced.

[0012] Step a2: reacting 1 mol of the linear phenolic resin modified polyether with 2-4 mol of isocyanoethyl methacrylate to obtain a phenolic resin modified polyurethane acrylate oligomer having a functionality of 2-4 and capable of participating in a photocuring reaction.

[0013] As a further technical solution of the present invention: the preparation method of the oligomer 2 comprises the following steps: Step b1: reacting 1 mol of polytetramethylene glycol with a molecular weight of 650-2000 with 2 mol of difunctional isocyanate (preferably dimer acid diisocyanate); Among them, the chemical formula of dimer acid diisocyanate is: Step b2: Add 2 mol HEMA (hydroxyethyl methacrylate) for end-capping to obtain polyurethane acrylate, and utilize the special structure of dimer acid diisocyanate to improve the toughness of the material.

[0014] The method for preparing a high-strength and high-toughness photocurable material as described above comprises the following steps: mixing oligomer 1, oligomer 2, a monofunctional diluent, a photoinitiator and other additives in a uniform proportion, and storing them away from light to form a high-strength and high-toughness photocurable material.

[0015] For example, the application of a high-strength and high-toughness photocurable material in 3D printed eyeglass frames.

[0016] In summary, the present invention includes at least one of the following beneficial technical effects: The invention discloses a high-strength and high-toughness photocurable material and a preparation method and application thereof. Oligomer 1 uses phenolic resin as an initial reactant, and obtains an acrylate-terminated modified polyurethane acrylate with adjustable functionality and molecular weight through a two-step method, thereby obtaining a modified oligomer with improved strength and toughness. Oligomer 2 uses special isocyanate and polytetramethylene ether diol as raw materials, and the introduced dimer acid diisocyanate has a long-chain alkyl group, thereby improving the toughness of the material. By adjusting the ratio of oligomer 1, oligomer 2 and a diluent, a high-strength and high-toughness photocurable material is obtained. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application; obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application without making creative work are within the scope of protection of the present application. Example

[0018] Add 1 mol of dicyclopentadiene straight-chain phenolic resin with a functionality of 3 into the reactor as an initiator, add 0.3% KOH as a catalyst, slowly add 6 mol of propylene oxide at 120°C, age for 1 hour after the reaction, add 5% water to the product, stir at 80°C for 1 hour, add phosphoric acid with a molar ratio of 1:1 to KOH for neutralization for 1 hour, and dehydrate at 120°C for 3 hours to obtain phenolic resin modified polyether.

[0019] 3 mol of isocyanoethyl methacrylate was added to the above product, and 0.03% of DBTL was used as a catalyst. The mixture was stirred at 80° C. for 3 h to obtain phenolic resin modified polyurethane acrylate oligomer A1. Example

[0020] 1 mol of dicyclopentadiene straight-chain phenolic resin with a functionality of 3 was added into the reactor as an initiator, 0.3% KOH was added as a catalyst, 21 mol of propylene oxide was slowly added at 120°C, the reaction was aged for 1 hour, 5% water was added to the product, stirred at 80°C for 1 hour, phosphoric acid with a molar ratio of 1:1 to KOH was added for neutralization for 1 hour, and dehydrated at 120°C for 3 hours to obtain phenolic resin modified polyether.

[0021] 3 mol of isocyanoethyl methacrylate was added to the above product, and 0.03% of DBTL (dibutyltin dilaurate) was used as a catalyst. The mixture was stirred at 80° C. for 3 h to obtain phenolic resin modified polyurethane acrylate oligomer A2. Example

[0022] 1 mol of dicyclopentadiene straight-chain phenolic resin with a functionality of 2 was added into the reactor as an initiator, 0.3% KOH was added as a catalyst, 14 mol of propylene oxide was slowly added at 120°C, the reaction was aged for 1 hour, 5% water was added to the product, stirred at 80°C for 1 hour, phosphoric acid with a molar ratio of 1:1 to KOH was added for neutralization for 1 hour, and dehydrated at 120°C for 3 hours to obtain phenolic resin modified polyether.

[0023] 2 mol of isocyanoethyl methacrylate was added to the above product, and 0.03% of DBTL (dibutyltin dilaurate) was used as a catalyst. The mixture was stirred at 80° C. for 3 h to obtain phenolic resin modified polyurethane acrylate oligomer A3. Example

[0024] 1 mol of polytetramethylene glycol with a molecular weight of 1000 and 2 mol of dimer acid diisocyanate were added to the reactor, stirred at 50°C for 0.5 h, 0.03% of DBTL (dibutyltin dilaurate) catalyst was added, reacted at 80°C for 3 h, and 2 mol of HEMA was added, and the reaction was continued for 3 h to obtain oligomer B1. Example

[0025] 1 mol of polytetramethylene glycol with a molecular weight of 2000 and 2 mol of dimer acid diisocyanate were added to the reactor, stirred at 50°C for 0.5 h, 0.03% of DBTL (dibutyltin dilaurate) catalyst was added, reacted at 80°C for 3 h, and 2 mol of HEMA was added, and the reaction was continued for 3 h to obtain oligomer B2.

[0026] Comparative Example 1: Add 1 mol of polytetramethylene glycol with a molecular weight of 2000 and 2 mol of isophorone diisocyanate into the reactor, stir at 50°C for 0.5 h, add 0.03% of DBTL (dibutyltin dilaurate) catalyst, react at 80°C for 3 h, then add 2 mol of HEMA and continue to react for 3 h to obtain oligomer C.

[0027] Light curing formula example: Advantages and positive effects compared with existing technologies: It can be seen from the performance test in Table 2 that the formulation of the special structure oligomers described in Examples 1-5 can obtain better strength and toughness, and by adjusting the type of phenolic resin and the amount of propylene oxide used in oligomer 1, the molecular weight of polytetramethylene ether glycol in oligomer 2, etc., the balance between strength and toughness is adjusted to obtain a high-strength and high-toughness photocurable material.

[0028] Oligomer 1: Through the combination of phenolic resin skeleton and flexible polyether chain segments, as well as acrylate end-capping, a balance between high cross-linking density and molecular chain flexibility is achieved, thereby improving strength and toughness; Oligomer 2: The long-chain alkyl structure of dimer acid diisocyanate is used to enhance the molecular chain entanglement and significantly improve the toughness of the material; Comprehensive performance: The examples show that the tensile strength is 47-55MPa, and the notched impact strength is 15-19KJ / m², which are significantly better than the comparative example (tensile strength 41-53MPa, notched impact strength 10-13KJ / m²).

[0029] The implementation principle of the present invention is as follows: the invention discloses a high-strength and high-toughness photocurable material and a preparation method and application thereof; oligomer 1 utilizes phenolic resin as an initial reactant, and obtains an acrylate-terminated modified polyurethane acrylate with adjustable functionality and molecular weight through a two-step method, thereby obtaining a modified oligomer with improved strength and toughness; oligomer 2 utilizes special isocyanate and polytetramethylene ether diol as raw materials, and the introduced dimer acid diisocyanate has a long-chain alkyl group, thereby improving the toughness of the material; by adjusting the ratio of oligomer 1, oligomer 2 and a diluent, a high-strength and high-toughness photocurable material is obtained.

[0030] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-strength and high-toughness photocurable material, characterized in that: The following components are included by weight: Oligomer 1: 10-40 parts; Oligomer 2: 10-40 parts; Monofunctional diluent: 10-20 parts, selected from acrylate monomers with Tg of 90-200°C; Photoinitiator: 1-3 parts; Other additives: 1-3 parts.

2. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The oligomer 1 is a phenolic resin modified polyurethane acrylate, which is prepared by ring-opening polymerization of linear phenolic resin and alkylene oxide and then capped with isocyanoethyl methacrylate.

3. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The oligomer 2 is a polyurethane acrylate obtained by reacting dimer acid diisocyanate with polytetramethylene ether diol and capping with HEMA.

4. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The monofunctional diluent is selected from at least one of dicyclopentanyl methacrylate, isobornyl methacrylate, trimethylcyclohexyl acrylate and acryloyl morpholine.

5. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The other additives include at least one of an antioxidant, a light stabilizer, a UV color paste, and an inorganic additive.

6. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The preparation method of the oligomer 1 comprises the following steps: Step a1: using 1 mol of a linear phenolic resin with a functionality of 2-4 as an initiator, and subjecting it to ring-opening polymerization with 2-30 mol of an alkylene oxide under KOH catalysis, and obtaining a linear phenolic resin modified polyether after neutralization; Step a2: reacting 1 mol of the linear phenolic resin modified polyether with 2-4 mol of isocyanoethyl methacrylate to obtain a phenolic resin modified polyurethane acrylate oligomer having a functionality of 2-4 and capable of participating in a photocuring reaction.

7. The high-strength and high-toughness photocurable material according to claim 1, characterized in that: The preparation method of the oligomer 2 comprises the following steps: Step b1: reacting 1 mol of polytetramethylene glycol having a molecular weight of 650-2000 with 2 mol of difunctional isocyanate; Step b2: Add 2 mol HEMA for end-capping to obtain polyurethane acrylate.

8. A method for preparing a high-strength and high-toughness photocurable material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: mixing oligomer 1, oligomer 2, a monofunctional diluent, a photoinitiator and other additives uniformly in proportion, and storing the mixture in a dark place to form a high-strength and high-toughness photocurable material.

9. Application of the high-strength and high-toughness photocurable material as described in any one of claims 1 to 7 in 3D printed eyeglass frames.

Images