Self-repairing acrylate photosensitive resin for 3D printing and manufacturing method thereof

Abstract

The application discloses a kind of self-repairing acrylate photosensitive resin for 3D printing and manufacturing method thereof, the self-repairing acrylate photosensitive resin includes filler nanocellulose and polymer matrix hydroxyethyl acrylate, the nanocellulose is nanocellulose with abundant surface hydroxyl group, nano-sized structure, the self-repairing performance of the self-repairing acrylate photosensitive resin is based on the interface hydrogen bond network between nanocellulose surface hydroxyl group and acrylate molecular chain end hydroxyl group is endowed, the self-repairing acrylate photosensitive resin described in the application can be printed into shape using DLP-3D printing equipment.The application solves the problem that 3D printing elastomer will inevitably produce micro-cracks, scratches, cracks and other problems due to external force during use, has the characteristics of raw material from biomass, green environmental protection, simple preparation process, has autonomous repair ability, has good mechanical properties and self-repairing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acrylate preparation, in particular to a 3D printing self-repairing acrylate photosensitive resin material and a preparation method thereof. BACKGROUND

[0002] DLP light-cured 3D printing technology is widely used in the consumer product field due to its high molding precision, lightweight printing, and batch manufacturing advantages. As 3D printing products enter the consumer product market, higher requirements are placed on the strength, toughness, wear resistance, and comfort of products. In daily use, consumer products will inevitably produce micro-cracks and fractures, greatly affecting their service life and service period. Therefore, photosensitive resin materials with self-repairing properties have gradually become a research focus.

[0003] Self-repairing refers to a material that can repair part or all of its performance under certain conditions after being affected by external forces to produce physical layer micro-cracks, notches, or damage. Self-repairing elastomers are divided into exogenous and endogenous types according to the repair mechanism. Compared with exogenous repair, endogenous repair can utilize dynamic non-covalent bonds such as van der Waals forces, pi-pi stacking, hydrogen bonds, and metal-ligand interactions for repair, has the advantages of high repair efficiency, spontaneous repair, and multiple repair, and can effectively improve the service life of the material. The self-repairing efficiency of the material can effectively improve its service life, but there is a contradiction between the mechanical strength and the self-repairing efficiency of the self-repairing material. Polymer-based composite materials have the advantages of high mechanical strength, good fatigue and friction resistance, etc. The addition of fillers can improve the strength of the material by utilizing the volume reinforcement effect, and the construction of reversible dynamic bonds between the interface of the fillers and the polymer molecular chains can endow the material with self-repairing properties, which can effectively improve the mechanical, thermal, and tribological properties of the polymer material, thus becoming a hope to solve the above problems.

[0004] Nanocellulose has the characteristics of being renewable, safe, green, environmentally friendly, non-toxic, etc., and is widely used in the preparation of self-repairing materials. The construction of dynamic non-covalent interactions between the interface of acrylate polymer molecular chains and nanocellulose can repair the material and endow it with repair properties. The volume reinforcement effect of nanocellulose and the interface non-covalent interaction can effectively improve the mechanical properties of the material, thereby effectively improving the performance of the material.

[0005] Therefore, there is a need in the market for a 3D printing self-repairing acrylate photosensitive resin with raw materials derived from biomass, green and environmentally friendly, simple preparation process, self-repairing ability, good mechanical properties, and self-repairing properties, and a manufacturing method thereof. SUMMARY

[0006] The present invention aims to provide a self-repairing acrylate photosensitive resin for 3D printing, which has biomass as its raw material, is green and environmentally friendly, has a simple preparation process, has self-repairing ability, and has good mechanical properties and self-repairing properties, and a method for manufacturing the same.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a self-healing acrylate photosensitive resin for 3D printing, the self-healing acrylate photosensitive resin comprising filler nanocellulose and a polymer matrix acrylate, the nanocellulose being nanocellulose having surface hydroxyl groups and a nano-sized structure, and a hydrogen bond network existing at the interface between the surface hydroxyl groups of the nanocellulose and the end hydroxyl groups of the acrylate molecular chain. The preparation method of the self-healing acrylate photosensitive resin comprises the following stages:

[0008] S1: Nanocellulose Preparation

[0009] ① Add natural cotton wool and saturated hydrochloric acid in a mass ratio of 1: (2.8-3.5) into a reaction vessel, heat to 50°C-60°C and mechanically stir for 24 hours at a rate of 500rpm-550rpm;

[0010] ② After filtering the acid-hydrolyzed solid from the hydrochloric acid using a suction filtration device, dilute and wash it with deionized water for 4-6 times, and then place the washed solid in a drying oven and dry it at 60°C-65°C for 18h-24h to obtain nanocellulose with a length and diameter of 20nm-200nm;

[0011] S2: Preparation of self-healing acrylic photosensitive resin

[0012] ① Filling a reaction vessel with nitrogen, under a nitrogen atmosphere, uniformly mixing acrylate, photoinitiator, active diluent, and nanocellulose in a mass ratio of 100: (1-5): (15-30): (20-60) to obtain the desired self-healing acrylate photosensitive resin for 3D printing; wherein the active diluent is specifically an active diluent mixed with alcohol ester.

[0013] In the above-mentioned self-repairing acrylate photosensitive resin for 3D printing: the acrylate is hydroxyethyl acrylate.

[0014] In the above-mentioned method for preparing the self-healing acrylate photosensitive resin for 3D printing: the photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0015] In the above-mentioned method for preparing the self-healing acrylate photosensitive resin for 3D printing: the active diluent component is obtained by compounding ethylene glycol and dimethyl carbonate in a molar ratio of 1:1.

[0016] In the above-mentioned preparation method of the self-healing acrylic photosensitive resin for 3D printing, in stage S3, the specific parameters are:

[0017] S2: Preparation of self-healing acrylic photosensitive resin

[0018] ① Add hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone, and catalyst 4-dimethylaminopyridine into a reactor, heat the solution to 100° C. and stir for 12 hours to obtain an acrylate prepolymer; wherein the hydroquinone accounts for 0.28wt.%-0.35wt.% of the total amount of acrylate, and the amount of 4-dimethylaminopyridine is 0.8wt.%-1.5wt.% of the total amount of acrylate; under a nitrogen atmosphere, the acrylate prepolymer, photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, active diluent, and nanocellulose are mixed in a weight ratio of (50-60): (1-1.5): (15-20): (20-30), the stirring speed is 1200 rpm, and the stirring time is 12 hours to obtain an acrylate photosensitive resin with self-healing properties.

[0019] Compared with the prior art, the present invention has the following advantages due to the adoption of the above technical solution:

[0020] (1) The self-healing acrylic photosensitive resin synthesized in the present invention has high stability. The material after 3D printing has good mechanical properties, thermal properties, etc., and can be used as a raw material for 3D printing elastomers.

[0021] (2) The preparation method used in the present invention is to first prepare nanocellulose by using an acid hydrolysis method, and then use the hydroxyl groups at the end of the acrylate molecular chain to form interfacial hydrogen bonds with the hydroxyl groups on the surface of the nanocellulose. After adding a diluent and a photoinitiator, a self-healing acrylate photosensitive resin that can be used for 3D printing is obtained; the raw materials of this preparation method are derived from biomass, and it has the advantages of being green and environmentally friendly and having a simple preparation process.

[0022] (3) The self-healing acrylic photosensitive resin prepared by the present invention was poured into a DLP 3D printing device for printing. After printing, the product was cured at high temperature to obtain an elastic component with self-healing capabilities. The mechanical properties of the component were significantly better than those of commercially available products, as follows: viscosity 2300 cp·s-3400 cp·s, tensile strength 4.55 MPa-11.4 MPa, elongation at break 720%-1350%, self-healing efficiency 76%-91%, and bending endurance 27,000-40,000 times.

[0023] Therefore, the present invention has the characteristics that the raw materials are derived from biomass, are green and environmentally friendly, have a simple preparation process, have self-repairing ability, and have good mechanical properties and self-repairing properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope image of the tensile cross-section of the material of the present invention with a scale of 100 μm;

[0025] Figure 2 This is a scanning electron microscope image of the tensile cross-section of the material of the present invention with a scale of 50 μm;

[0026] Figure 3 This is a scanning electron microscope image of the tensile cross-section of the material of the present invention with a scale of 10 μm. DETAILED DESCRIPTION

[0027] Example 1

[0028] (1) Natural cotton lint and hydrochloric acid in a mass ratio of 1:3 were added to a beaker, and the mixture was stirred at 50°C for 24 h at a speed of 500 rpm. After the reaction, the acid-hydrolyzed cotton lint was filtered from the hydrochloric acid by suction, and diluted and washed with ultrapure water for a total of 4 times. The sample was dried in a drying oven at 60°C for 24 h to obtain nanocellulose.

[0029] (2) Ethylene glycol and dimethyl carbonate were mixed in a molar ratio of 1:1, and stirred at 400 rpm for 30 minutes to obtain a composite active diluent;

[0030] (3) Adding hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone (hydroquinone accounts for 0.3 wt.% of the total amount of acrylate), and catalyst 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine is 1 wt.% of the total amount of acrylate) into a reaction kettle, heating the solution to 100° C. and stirring for 12 h to obtain an acrylate prepolymer;

[0031] (4) Under a nitrogen atmosphere, an acrylate prepolymer, a photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, a reactive diluent, and nanocellulose were mixed in a ratio of 50:1:15:20 by weight, with a stirring speed of 1200 rpm and a stirring time of 12 h to obtain an acrylate photosensitive resin with self-healing properties;

[0032] (5) Pour the acrylic photosensitive resin into the DLP 3D printing device for printing. The printing parameters are: UV light band 405nm, UV light power 9mW / cm 2 The printing layer thickness is 0.1 mm, the exposure time of a single layer is 2.5 s, and the workpiece is cured at high temperature after printing, with the curing temperature being 80 ° C and the curing time being 6 h to obtain a 3D printed self-healing acrylic elastomer.

[0033] Example 2

[0034] (1) In a beaker, add natural cotton flock and hydrochloric acid with a mass ratio of 1:3, stir at 50°C for 24h, the rotation speed is 500rpm, after the reaction is completed, use suction filtration to filter the acid-hydrolyzed cotton flock from the hydrochloric acid, dilute and wash with ultrapure water, a total of 4 times, dry the sample in a drying oven at 60°C for 24h, to obtain nanocellulose;

[0035] (2) Mix ethylene glycol and dimethyl carbonate according to a molar ratio of 1:1, stir at 400rpm for 30min, to obtain a complex active diluent;

[0036] (3) In a reaction kettle, add hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone (hydroquinone accounts for 0.3wt.% of the total amount of acrylate), catalyst 4-dimethylaminopyridine (4-dimethylaminopyridine is used in an amount of 1wt.% of the total amount of acrylate), heat the solution to 100°C and stir for 12h to obtain an acrylate prepolymer;

[0037] (4) Under a nitrogen atmosphere, mix the acrylate prepolymer, photoinitiator 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide, active diluent, and nanocellulose according to a weight ratio of 50:1:15:30, the stirring speed is 1200rpm, and the stirring time is 12h, to obtain an acrylate photosensitive resin with self-repairing properties;

[0038] (5) Pour the acrylate photosensitive resin into a DLP 3D printing device for printing, the printing parameters are: UV light wavelength 405nm, UV light power 9mW / cm 2 , printing layer thickness 0.1mm, single layer exposure time 2.5s, after printing, the product is subjected to high-temperature curing, the curing temperature is 80°C, and the curing time is 6h, to obtain a 3D printed self-repairing acrylate elastomer.

[0039] Example 3

[0040] (1) In a beaker, add natural cotton flock and hydrochloric acid with a mass ratio of 1:3, stir at 50°C for 24h, the rotation speed is 500rpm, after the reaction is completed, use suction filtration to filter the acid-hydrolyzed cotton flock from the hydrochloric acid, dilute and wash with ultrapure water, a total of 4 times, dry the sample in a drying oven at 60°C for 24h, to obtain nanocellulose;

[0041] (2) Mix ethylene glycol and dimethyl carbonate according to a molar ratio of 1:1, stir at 400rpm for 30min, to obtain a complex active diluent;

[0042] (3) Adding hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone (hydroquinone accounts for 0.3 wt.% of the total amount of acrylate), and catalyst 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine is 1 wt.% of the total amount of acrylate) into a reaction kettle, heating the solution to 100° C. and stirring for 12 h to obtain an acrylate prepolymer;

[0043] (4) Under a nitrogen atmosphere, an acrylate prepolymer, a photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, a reactive diluent, and nanocellulose were mixed in a ratio of 50:1:15:40 by weight, with a stirring speed of 1200 rpm and a stirring time of 12 h to obtain an acrylate photosensitive resin with self-healing properties;

[0044] (5) Pour the acrylic photosensitive resin into the DLP 3D printing device for printing. The printing parameters are: UV light band 405nm, UV light power 9mW / cm 2 The printing layer thickness is 0.1 mm, the exposure time of a single layer is 2.5 s, and the workpiece is cured at high temperature after printing, with the curing temperature being 80 ° C and the curing time being 6 h to obtain a 3D printed self-healing acrylic elastomer.

[0045] Example 4

[0046] (1) Natural cotton lint and hydrochloric acid in a mass ratio of 1:3 were added to a beaker, and the mixture was stirred at 50°C for 24 h at a speed of 500 rpm. After the reaction, the acid-hydrolyzed cotton lint was filtered from the hydrochloric acid by suction, and diluted and washed with ultrapure water for a total of 4 times. The sample was dried in a drying oven at 60°C for 24 h to obtain nanocellulose.

[0047] (2) Ethylene glycol and dimethyl carbonate were mixed in a molar ratio of 1:1, and stirred at 400 rpm for 30 minutes to obtain a composite active diluent;

[0048] (3) Adding hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone (hydroquinone accounts for 0.3 wt.% of the total amount of acrylate), and catalyst 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine is 1 wt.% of the total amount of acrylate) into a reaction kettle, heating the solution to 100° C. and stirring for 12 h to obtain an acrylate prepolymer;

[0049] (4) Under a nitrogen atmosphere, an acrylate prepolymer, a photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, a reactive diluent, and nanocellulose were mixed in a ratio of 50:1:15:50 by weight, with a stirring speed of 1200 rpm and a stirring time of 12 h to obtain an acrylate photosensitive resin with self-healing properties;

[0050] (5) Pour the acrylic photosensitive resin into the DLP 3D printing device for printing. The printing parameters are: UV light band 405nm, UV light power 9mW / cm 2 The printing layer thickness is 0.1 mm, the exposure time of a single layer is 2.5 s, and the workpiece is cured at high temperature after printing, with the curing temperature being 80 ° C and the curing time being 6 h to obtain a 3D printed self-healing acrylic elastomer.

[0051] Example 5

[0052] (1) Natural cotton lint and hydrochloric acid in a mass ratio of 1:3 were added to a beaker, and the mixture was stirred at 50°C for 24 h at a speed of 500 rpm. After the reaction, the acid-hydrolyzed cotton lint was filtered from the hydrochloric acid by suction, and diluted and washed with ultrapure water for a total of 4 times. The sample was dried in a drying oven at 60°C for 24 h to obtain nanocellulose.

[0053] (2) Ethylene glycol and dimethyl carbonate were mixed in a molar ratio of 1:1, and stirred at 400 rpm for 30 minutes to obtain a composite active diluent;

[0054] (3) Adding hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone (hydroquinone accounts for 0.3 wt.% of the total amount of acrylate), and catalyst 4-dimethylaminopyridine (the amount of 4-dimethylaminopyridine is 1 wt.% of the total amount of acrylate) into a reaction kettle, heating the solution to 100° C. and stirring for 12 h to obtain an acrylate prepolymer;

[0055] (4) Under a nitrogen atmosphere, an acrylate prepolymer, a photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, a reactive diluent, and nanocellulose were mixed in a ratio of 50:1:15:60 by weight, with a stirring speed of 1200 rpm and a stirring time of 12 h to obtain an acrylate photosensitive resin with self-healing properties;

[0056] (5) Pour the acrylic photosensitive resin into the DLP 3D printing device for printing. The printing parameters are: UV light band 405nm, UV light power 9mW / cm 2 The printing layer thickness is 0.1 mm, the exposure time of a single layer is 2.5 s, and the workpiece is cured at high temperature after printing, with the curing temperature being 80 ° C and the curing time being 6 h to obtain a 3D printed self-healing acrylic elastomer.

[0057] The self-healing acrylic photosensitive resins of Examples 1-5 were poured into a DLP 3D printing device for printing. After printing, the parts were cured at high temperature to obtain elastic parts with self-healing capabilities. The performance test conditions are as follows:

[0058] Tensile properties: The mechanical properties of the printed specimens were measured using a CTM8010 microcomputer-controlled electronic universal material testing machine (Xie Qiang Instrument Manufacturing (Shanghai) Co., Ltd.) in accordance with GB / T 1040.1-2018 Determination of tensile properties of plastics Part 1: General principles. The gauge length was 40 mm and the tensile rate was 20 mm / min. The self-repairing performance was: self-repairing efficiency = σ 自修复后拉伸强度 / σ 自修复前拉伸强度 The bending endurance test was conducted using a CTM8010 microcomputer-controlled electronic universal material testing machine in accordance with GB / T 9341-2008, Determination of the Flexural Properties of Plastics, with a bending angle of 90° and a bending speed of 1 bend / second. Resin viscosity was tested using an LC-NDJ-5T digital viscometer (Hunan Lichen Instrument Technology Co., Ltd.) in accordance with GB / T 22314-2008, Determination of the Viscosity of Epoxy Resins.

[0059] Table 1 shows the main performance indicators of the self-repairing photosensitive resins of Examples 1-5

[0060]

[0061] As can be seen from Table 1, the self-healing acrylic photosensitive resin material for 3D printing prepared by the present invention has good mechanical properties and self-healing efficiency, and can be used as a raw material for 3D printed elastic components to provide better strength, toughness and service life.

[0062] The above description of the disclosed embodiments is intended solely to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A self-repairing acrylate photosensitive resin for 3D printing, comprising a filler of nanocellulose and a polymer matrix of hydroxyethyl acrylate, characterized in that: The nanocellulose is a nanocellulose having surface hydroxyl groups and a nano-sized structure. A hydrogen bond network exists at the interface between the surface hydroxyl groups of the nanocellulose and the end hydroxyl groups of the hydroxyethyl acrylate molecular chain. The preparation method of the self-repairing acrylate photosensitive resin includes the following stages: S1: Nanocellulose Preparation ① Add natural cotton wool and saturated hydrochloric acid in a mass ratio of 1: (2.8-3.5) into a reaction vessel, heat to 50°C-60°C and mechanically stir for 24 hours at a rate of 500rpm-550rpm; ② After filtering the acid-hydrolyzed solid from the hydrochloric acid using a suction filtration device, dilute and wash it with deionized water for 4-6 times, and then place the washed solid in a drying oven and dry it at 60°C-65°C for 18h-24h to obtain nanocellulose with a length and diameter of 20nm-200nm; S2: Preparation of self-healing acrylic photosensitive resin ① Add hydroxyethyl acrylate monomer, polymerization inhibitor hydroquinone, and catalyst 4-dimethylaminopyridine into a reactor, heat the solution to 100° C. and stir for 12 hours to obtain an acrylate prepolymer; wherein the hydroquinone accounts for 0.28wt.%-0.35wt.% of the total amount of acrylate, and the amount of 4-dimethylaminopyridine is 0.8wt.%-1.5wt.% of the total amount of acrylate; under a nitrogen atmosphere, the acrylate prepolymer, photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, active diluent, and nanocellulose are mixed in a ratio of (50-60): (1-1.5): (15-20): (20-30) by weight, and the stirring speed is 1200 rpm for 12 hours to obtain an acrylate photosensitive resin with self-healing properties; wherein the active diluent component is obtained by compounding ethylene glycol and dimethyl carbonate in a molar ratio of 1:1.

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