Preparation method of Australian tea tree composite microspheres and 3D printing composite materials thereof

Abstract

The invention discloses a method for preparing an Australian tea tree powder composite microsphere and a 3D printing composite material thereof, wherein the components include 65-90 parts by weight of polycaprolactone, 5-30 parts by weight of Australian tea tree powder composite microsphere, 0.1-1 parts by weight of nano-microcrystalline cellulose, 0.5-2 parts by weight of tributyl citrate, 0.2-2 parts by weight of diatomaceous earth powder and 0.1-2 parts by weight of calcium carbonate. The 3D printing composite material prepared by the present invention has excellent antibacterial rate, excellent curing molding efficiency, good extrusion fluency and good mechanical properties, is non-toxic and harmless, is green and environmentally friendly and can be naturally biodegraded, makes full and reasonable use of waste residues of Australian tea trees, etc., has relatively low and reasonable economic cost, mature production process technology, and high degree of industrialization.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanocomposite materials, and in particular relates to a method for preparing Australian tea tree composite microspheres and a 3D printed composite material thereof. Background Art

[0002] With the continuous development, use and promotion of 3D printing technology, the concept of 3D printing has become less magical in people's lives in recent years. More and more people are using and experiencing it, and its application areas are becoming more and more extensive. In the application of 3D printing, there are two common forms, mainly printers and printing pens. Printers are divided into melt extrusion molding, light curing molding, laser sintering molding, glue bonding molding and other forms according to different application requirements. Food printers, biological printers, 3D engraving printers, etc. have also appeared one after another; and printing pens are also mainly divided into high-temperature printing pens and low-temperature printing pens. With people's use, more and more people begin to use low-temperature printing pens, mainly because low temperature is safe and more suitable for children aged 5-15 years old, and they are used more and more. However, the main low-temperature material consumables on the market are mainly polycaprolactone or modified polycaprolactone, most of which are raw materials without antibacterial properties, or a small part of them use metal ions such as silver ion antibacterial agents or inorganic salt antibacterial materials, or a small part of them use chemical materials such as quaternary ammonium salts as antibacterial; the antibacterial effect of the above categories of antibacterial materials is relatively good, but they are more or less toxic, and long-term contact will have adverse effects on the user's health and growth and development.

[0003] A Chinese patent (patent number: CN201910681825.7) discloses a biological feed made of Melaleuca alternifolia (Australian tea tree) residue powder. The weight percentage of the feed is: 25-54.95% corn, 35-65% Australian tea tree biological powder, 2% cottonseed meal, 3% peanut meal, 1.5% calcium hydrogen phosphate, 0.9% stone powder, 0.2% salt, 0.5% vitamin premix, 0.1% choline chloride, 0.15% lysine, 0.2% methionine, 1% Australian tea tree essential oil, and 0.5% hydrosol. According to a brief introduction in its embodiment, the Australian tea tree biological powder is combined with feed raw materials in a certain proportion to produce tea tree biological antibiotic feed, which is mainly produced by adding Australian tea tree essential oil and tea tree biological powder to replace the antibiotics in the existing feed to enhance the antiviral ability of pigs and poultry, prevent swine fever, chicken plague, etc., and improve the taste of meat, tenderness, fragrance and crispness. The antibacterial properties of the Australian tea tree powder and chitosan oligosaccharide composite microspheres in this application are more in vitro antibacterial, which is completely different from the principle and introduction of the function produced by oral administration to animals described in the patent, and there is no inspiration to draw on.

[0004] A Chinese patent (patent number: CN201911292273.7) discloses a hemp biofertilizer based on the residues of Australian tea tree essential oil processing and a production method thereof, comprising the following parts by weight: 200-240 parts of Australian tea tree essential oil processing residues, 50-70 parts of decomposed matter, 10-15 parts of Chinese medicine residues, 20-30 parts of peanut bran, 15-20 parts of furfural residues, 3-5 parts of coconut shell charcoal, 8-12 parts of sustained-release agents, 0.04-0.07 parts of biological agents, 0.01-0.02 parts of trace elements. Some of the raw materials are crushed, fermented, mixed, and sterilized by ultraviolet irradiation, etc., and then bagged to obtain a finished fertilizer. Its main purpose is to inhibit bacteria, repel insects, increase production, and improve soil. The main function of the Australian tea tree composite microspheres in this application is antibacterial. Whether it is from the dosage of Australian tea tree powder or the preparation method of Australian tea tree powder-chitosan oligosaccharide composite antibacterial microspheres, there are huge differences from the implementation method of this application. The main purpose and application fields are also very different. The antibacterial effect of Australian tea tree and its essential oil is also well known to technicians in this field, but the method and effect of preparing composite antibacterial agent microspheres can basically not get substantial and useful inspiration from its introduction. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing Australian tea tree composite microspheres and 3D printing composite materials thereof.

[0006] In order to achieve the above object, the technical solution provided by the present invention is:

[0007] A method for preparing Australian tea tree composite microspheres comprises the following steps:

[0008] (1) Cutting the branches of the Australian tea tree into small pieces or segments, baking them until dry, and then crushing them, passing them through a sieve of 1000 or above mesh to obtain Australian tea tree powder;

[0009] (2) adding the obtained Australian tea tree powder to the modified solution and dispersing it evenly, first subjecting it to ultrasonic treatment (10-20 min), then stirring and reacting it at 50-70°C for 3-8 h, then keeping stirring and cooling it to room temperature, filtering, washing, drying, refining it, and passing it through a sieve of 600 or above mesh to obtain modified Australian tea tree powder;

[0010] Wherein, the weight ratio of the content of the modifier in the modified solution to the Australian tea tree powder is 1:(1-10);

[0011] (3) preparing an aqueous solution with a total concentration of polyvinyl alcohol and polyvinyl pyrrolidone of 2.5-3.5 wt %, wherein the weight ratio of polyvinyl alcohol to polyvinyl pyrrolidone is (4-10):(1-5); preparing an aqueous solution with a concentration of chitosan oligosaccharide of 1-2 wt %, wherein the molecular weight of chitosan oligosaccharide is 500-5000; and then mixing the two aqueous solutions evenly to obtain a mixed solution; wherein the weight ratio of the aqueous solution of polyvinyl alcohol and polyvinyl pyrrolidone to the aqueous solution of chitosan oligosaccharide is (1-5):(1-10);

[0012] (4) adding the modified Australian tea tree powder to the mixed solution and dispersing it evenly, preparing powder particles through a spray drying process, drying, refining, and passing through a sieve of 400 or above mesh to obtain Australian tea tree composite microspheres; wherein the weight ratio of the modified Australian tea tree powder to the mixed solution is 1:(10-100).

[0013] Preferably, the Australian tea tree trunks are taken from Ruyuan Yao Autonomous County of Shaoguan City or Wengyuan County of Shaoguan City, and are one or more of Australian tea tree waste branches after essential oil extraction (conventional steam distillation method) and Australian tea tree trunks without essential oil extraction.

[0014] Preferably, the modifier solution is an ethanol solution with a modifier concentration of 3-8 wt %, and the pH value is adjusted to 8-9 with triethanolamine.

[0015] More preferably, the modifier is a composition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethylenetriamine and ammonium dodecylbenzenesulfonate, wherein the mass ratio of the three is (2-10): (0.1-0.5): (1-3).

[0016] Preferably, the spray drying process is controlled as follows: inlet temperature is 103° C., outlet temperature is 70° C., and the frequency of the sprayer is between 20-40 Hz.

[0017] The Australian tea tree composite microspheres are used to prepare a 3D printing composite material, comprising the following steps:

[0018] (i) 5-30 parts by weight of the Australian tea tree composite microspheres, 0.1-1 parts by weight of microcrystalline cellulose, 0.2-2 parts by weight of diatomaceous earth powder and 0.1-2 parts by weight of calcium carbonate are mixed evenly to obtain a mixed powder A for standby use; 0.5-2 parts by weight of tributyl citrate is added to 65-90 parts by weight of polycaprolactone and mixed evenly, and then the obtained mixed powder A is added and mixed evenly to obtain a mixture B;

[0019] (ii) adding the mixture B into a twin-screw extruder for melt mixing, extrusion, cooling, pelletizing, and drying to obtain polycaprolactone composite pellets;

[0020] (iii) adding the obtained polycaprolactone composite pellets into a single screw extruder for melt extrusion, drawing, cooling, air-drying, and collecting the wires to obtain the Australian tea tree 3D printing composite material.

[0021] Preferably, the temperature of the twin-screw extruder is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in the die zone, the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min.

[0022] Preferably, the temperature of the single screw is set to: 90°C in zone 1, 98°C in zone 2, 95°C in zone 3, and 91°C in the die zone, and the speed of the single screw is 25 r / min.

[0023] In the above preparation method, various required pigments can be added and mixed according to color requirements to prepare the required color.

[0024] The technical solution of the present invention has the following technical features and beneficial effects:

[0025] (1) The present invention uses Australian tea tree branches or waste residues after essential oil extraction to crush into powder of a certain size, and uses N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethylenetriamine and ammonium dodecylbenzenesulfonate in a certain proportion to prepare a modified composition, so that the modified Australian tea tree powder has both hydrophilic groups and lipophilic groups, which can better generate affinity with polyvinyl alcohol, polyvinyl pyrrolidone and chitosan oligosaccharides in aqueous solution, with the modified Australian tea tree powder as the core, polyvinyl alcohol, polyvinyl pyrrolidone and chitosan oligosaccharides The surfaces of the modified Australian tea tree powders are fused and wrapped in the form of a membrane, so that they form a unified organic composite whole and form microspherical particles. The formation of the outer membrane not only protects the Australian tea tree powder, mainly protects some active substances contained therein, such as active essential oils, active colloids, etc., but also allows the active ingredients in the Australian tea tree powder to produce a certain synergistic effect with the active groups in the chitosan oligosaccharides, achieving an effect of one plus one being greater than two, which is significantly improved compared to the effect of using only Australian tea tree powder or chitosan oligosaccharides.

[0026] (2) The reagents or solvents used in the present invention are relatively non-toxic substances, most of which are natural substances, such as Australian tea tree powder, chitosan oligosaccharides, microcrystalline cellulose, diatomaceous earth, etc. The antibacterial ingredients do not contain heavy metals and other ingredients. Compared with similar antibacterial ingredients such as silver ions, zinc ions, quaternary ammonium salts, etc. currently available on the market, they are more environmentally friendly, pollution-free and more sustainable to the ecological environment. In addition, its main polymer matrix material polycaprolactone is also a new type of green material that is green, environmentally friendly and biodegradable. The printing wire prepared and produced is suitable for use in 3D printing pens, which is safer and more reliable for users than existing products on the market.

[0027] (3) The present invention adopts a spray drying process to prepare Australian tea tree composite microspheres, which can obtain microsphere particles with higher uniformity and better composite effect; adding microcrystalline cellulose to the matrix can act as a nucleating agent, which can accelerate the crystallization rate of the matrix, so that after the wire is extruded, a large number of microcrystalline areas are formed during the cooling process, and the material is quickly cooled and solidified; adding diatomaceous earth powder can improve the comprehensive mechanical properties of the material under certain conditions, and can also help the solidification of the matrix material; adding tributyl citrate can not only act as a dispersant to evenly disperse the numerous microparticles, but also act as a plasticizer to improve the processability of the composite material, reduce the melting temperature of the composite material, and enable the wire to maintain good fluidity during use, and it itself is also a non-toxic and environmentally friendly additive; and the purpose of adding calcium carbonate powder is mainly to improve the overall whiteness of the printing wire or composite material, so that the material of the present invention can be more easily formulated with richer colors, and also make it have a wider range of applications.

[0028] (4) The present invention uses Australian tea tree powder as an antibacterial and additive component. On the one hand, this is because the raw material itself has good antibacterial properties, and after modification and compounding, it obtains more excellent antibacterial properties. On the other hand, it also provides a good solution for the treatment of waste residues after the extraction and processing of Australian tea tree essential oil. Compared with some simple composting treatments, the solution provided by the present invention can obtain higher commercial value. It also adheres to the concept of green environmental protection and reuses the waste residue in a more appropriate way to realize its due value. Moreover, the printing material of the present invention itself is also a green, environmentally friendly and naturally degradable material. After use, it can also be used as direct composting or slow-release composting for recycling again. In addition, the preparation method and process of the 3D printing composite material introduced in the present invention are relatively mature and stable, the preparation and production process is simple and convenient, the economic cost is reasonably low, and the existing market or future market prospects are considerable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0030] Figure 1 It is a flow chart of the preparation process and application process of the present invention.

[0031] Figure 2 This is an optical electron microscope image of the Australian tea tree powder of the present invention.

[0032] Figure 3 This is an optical electron microscope image of the Australian tea tree composite microspheres of the present invention. DETAILED DESCRIPTION

[0033] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and steps, can be combined in any manner.

[0034] Any feature disclosed in this specification (including any additional claims, abstracts and drawings), unless otherwise stated, may be replaced by other alternative features that are equivalent or have similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features. Among them, the materials used in the following embodiments are as follows, but the present invention is not limited thereto.

[0035] Australian tea tree composite microspheres: The preparation steps are as follows: (1) firstly cutting the waste residue of Australian tea tree branches after essential oil extraction into small pieces or segments, baking to dryness, crushing with a pulverizer, and screening to obtain Australian tea tree powder with a particle size of 1000 mesh or above; (2) then adding a modifier to ethanol to prepare a modified solution with a concentration of 5wt%, and adjusting the pH value to 8-9 with triethanolamine, adding the Australian tea tree powder to the modified solution to disperse evenly, and firstly performing ultrasonic treatment for 15 minutes. , and then stirred, the modification time was 4h, the modification temperature was 60℃, and the stirring was maintained while cooling naturally to room temperature, filtered, washed, dried, and refined to obtain modified Australian tea tree powder of 600 mesh and above; wherein the weight ratio of the modifier to the Australian tea tree powder was 1:5, the pH value of the modified solution was maintained at 8-9, and the modifier was a composition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethylenetriamine and ammonium dodecylbenzenesulfonate, and the mass fraction ratio was 5:0.1: 1; (3) Then, polyvinyl alcohol and polyvinyl pyrrolidone are added to deionized water, heated to 70°C in a water bath, stirred and dissolved, and a polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution with a concentration of 3wt% is prepared, and the weight ratio of the two is 4:2; chitosan oligosaccharide is added to deionized water, heated to 60°C in a water bath, stirred and dissolved, and a chitosan oligosaccharide aqueous solution with a concentration of 1.5wt%, wherein the molecular weight of chitosan oligosaccharide is 500-5000; then the polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution is added to the chitosan oligosaccharide aqueous solution and stirred evenly to obtain a mixed solution, wherein the weight ratio of the two aqueous solutions is 1:2; (4) Finally, the modified Australian tea tree powder is added to the mixed solution and stirred and dispersed until uniform; a spray dryer is used to prepare powder particles through a spray drying process, and the powder particles are further placed in a 50°C oven for drying for 6 hours, refined, and screened to obtain Australian tea tree composite microspheres of 400 mesh and above, wherein the mass ratio of the modified Australian tea tree powder to the mixed solution is 1:30.

[0036] Australian tea tree powder microspheres: The preparation steps are as follows: (1) firstly cut the branches of the Australian tea tree after essential oil extraction into small pieces or small segments, bake until dry, crush them with a pulverizer, and screen them to obtain Australian tea tree powder with a particle size of 1000 mesh or more; (2) then add the modifier to ethanol to prepare a modification solution with a mass fraction of 5%, and adjust the pH value to 8-9 with triethanolamine, add the Australian tea tree powder to the modification solution and disperse it evenly, first perform ultrasonic treatment for 15 minutes, then stir, the modification time is 4 hours, the modification temperature is 60°C, keep stirring and naturally cool to room temperature, filter, wash, dry, and refine to obtain modified Australian tea tree powder with a particle size of 600 mesh or more; wherein the mass fraction ratio of the modifier to the Australian tea tree powder is 1:5, the pH value of the modification solution is maintained at about 8, and the modifier is a composition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethylenetriamine and ammonium dodecylbenzenesulfonate, and its mass fraction is 200 μg / cm2. The ratio of polyvinyl alcohol and polyvinyl pyrrolidone is 5:0.1:1; (3) Then, polyvinyl alcohol and polyvinyl pyrrolidone are added to deionized water, heated to 70°C in a water bath, stirred and dissolved, and a polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution with a mass fraction of 3% is prepared, and the mass fraction ratio is 4:2; calcium carbonate powder is dispersed in deionized water to prepare a calcium carbonate mixed solution with a mass fraction of 1.5%; the polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution is then added to the calcium carbonate mixed solution and stirred evenly to obtain a mixed solution with a mass fraction ratio of 1:2; (4) Finally, the modified Australian tea tree powder is added to the polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution, stirred and dispersed until uniform; a spray dryer is used to prepare powder particles through a spray drying process, and the particles are further placed in a 50°C oven for drying for 6 hours, refined, and screened to obtain Australian tea tree composite microspheres of 400 mesh and above, wherein the mass ratio of the modified Australian tea tree powder to the mixed solution is 1:30.

[0037] Chitosan microspheres: first, polyvinyl alcohol and polyvinyl pyrrolidone are added to deionized water, heated to 70°C in a water bath, stirred to dissolve, and a polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution with a mass fraction of 3% is prepared, and the mass fraction ratio is 4:2; chitosan oligosaccharide is added to deionized water, heated to 60°C in a water bath, stirred to dissolve, and a chitosan oligosaccharide aqueous solution with a mass fraction of 1.5%, wherein the molecular weight of chitosan oligosaccharide is 500-5000; then the polyvinyl alcohol-polyvinyl pyrrolidone aqueous solution is added to the chitosan oligosaccharide aqueous solution and stirred evenly to obtain a mixed solution with a mass fraction ratio of 1:2; finally, calcium carbonate powder is dispersed in the mixed solution and stirred to disperse evenly; a spray dryer is used to prepare powder particles through a spray drying process, and the powder particles are further placed in a 50°C oven for drying for 6 hours, refined, and screened to obtain Australian tea tree composite microspheres of 400 mesh and above, wherein the mass ratio of calcium carbonate powder to the mixed solution is 1:30.

[0038] Hemp stalk powder: Use the same equipment as Australian tea tree crushing to crush the hemp stalk and refine it to obtain a powder with a size of 400 mesh or more.

[0039] Microcrystalline cellulose: Microcrystalline cellulose with a size of 1000-2000 mesh is used.

[0040] Diatomaceous earth: Use diatomaceous earth with a size of 500-1000 mesh.

[0041] Calcium carbonate: Calcium carbonate with a size of 1000 mesh or more is used.

[0042] Example 1

[0043] First, 5 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 90 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0044] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0045] Finally, the dried polycaprolactone composite pellets were added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain the Australian tea tree 3D printing composite material; the single screw temperature was set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed was 25 r / min.

[0046] Example 2

[0047] First, 10 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 85 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0048] The mixture was then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing was dried in a vacuum oven at 50°C for 8 hours to obtain a dry Australian tea tree 3D printing composite material; wherein the twin-screw temperature was set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die head zone, the twin-screw speed was 32 r / min, and the pelletizing speed was 12.4 r / min;

[0049] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0050] Example 3

[0051] First, 15 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 80 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0052] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0053] Finally, the dried polycaprolactone composite pellets were added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain the Australian tea tree 3D printing composite material; the single screw temperature was set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed was 25 r / min.

[0054] Example 4

[0055] First, 20 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 75 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0056] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0057] Finally, the dried polycaprolactone composite pellets were added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain the Australian tea tree 3D printing composite material; the single screw temperature was set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed was 25 r / min.

[0058] Example 5

[0059] First, 25 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 70 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0060] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0061] Finally, the dried polycaprolactone composite pellets were added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain the Australian tea tree 3D printing composite material; the single screw temperature was set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed was 25 r / min.

[0062] Example 6

[0063] First, 30 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 65 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0064] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0065] Finally, the dried polycaprolactone composite pellets were added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain the Australian tea tree 3D printing composite material; the single screw temperature was set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed was 25 r / min.

[0066] Comparative Example 1

[0067] First, 15 parts by weight of Australian tea tree powder microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 80 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0068] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0069] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0070] Comparative Example 2

[0071] First, 15 parts by weight of chitosan microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 80 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0072] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0073] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0074] Comparative Example 3

[0075] First, 15 parts by weight of hemp stalk powder, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 80 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0076] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0077] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0078] Comparative Example 4

[0079] First, 15 parts by weight of Australian tea tree composite microspheres, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 80.5 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0080] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0081] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0082] Comparative Example 5

[0083] First, 15 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose, 2 parts by weight of diatomaceous earth powder and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 81.5 parts by weight of polycaprolactone is added to the mixed powder, and the mixture is continuously mixed until uniform to obtain a mixture;

[0084] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0085] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0086] Comparative Example 6

[0087] First, 15 parts by weight of Australian tea tree composite microspheres, 0.5 parts by weight of microcrystalline cellulose and 1 part by weight of calcium carbonate are fully mixed to obtain a mixed powder for standby use; 1.5 parts by weight of tributyl citrate is added to 82 parts by weight of polycaprolactone and mixed evenly, and then the mixed powder is added and mixed evenly to obtain a mixture;

[0088] The mixture is then added to a twin-screw mixing extruder for melt mixing, extrusion, cooling, pelletizing, and the pelletizing is dried in a vacuum oven at 50°C for 8 hours to obtain dry polycaprolactone composite pelletizing; wherein the twin-screw temperature is set to: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in die zone; the twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min;

[0089] Finally, the dried polycaprolactone composite pellets are added to a single-screw extruder for heating, melt extrusion, wire drawing, cooling, air drying, and wire collection to obtain polycaprolactone composite wires for 3D printing; wherein, the single screw temperature is set to: 90°C in zone one, 98°C in zone two, 95°C in zone three, and 91°C in the die head zone, and the single screw speed is 25 r / min.

[0090] Comparative Example 7

[0091] Pure polycaprolactone is added into a single-screw extruder, heated, melted and extruded, and then drawn, cooled, air-dried and the wires are collected to obtain polycaprolactone composite wires for 3D printing. The temperatures of the single screw are set to: 90°C in zone one, 98°C in zone two, 95°C in zone three and 91°C in die head zone, and the speed of the single screw is 25 r / min.

[0092] Comparative Example 8

[0093] The polycaprolactone 3D printing wire currently available on the market is off-white in color, similar to the material prepared by the present invention, has a wire diameter between 1.70-1.79 mm, and a production date close to the date of the experiment conducted by the present invention.

[0094] Performance evaluation:

[0095] The evaluation results of the 3D printing wires and test samples obtained in Examples 1-6 and Comparative Examples 1-8 are shown in Table 1.

[0096] Table 1 Test results of examples and comparative examples

[0097]

[0098] Test results: According to the test results of Examples 1-6, it can be seen that as the weight of the Australian tea tree composite microspheres increases, the antibacterial rate also increases. Compared with the blank comparative example (Comparative Example 7), the antibacterial rate has a significant increase; According to the test results of Example 3 and Comparative Examples 1-3, it can be seen that the Australian tea tree powder and chitosan oligosaccharide composite microspheres have better and more obvious antibacterial effects than the single Australian tea tree powder microspheres and chitosan oligosaccharide microspheres. Compared with the hemp stalk powder of the same type of antibacterial plant powder comparative example 3, the Australian tea tree composite microspheres prepared by the present invention have more obvious antibacterial effects and a higher antibacterial rate. According to the test results of Example 3 and Comparative Example 4, it can be seen that if microcrystalline cellulose is not added, the tensile strength, elongation at break and flexural strength of the composite material will decrease to a certain extent, and the average curing time will also increase. The main factor is that the addition of microcrystalline cellulose particles will cause the polycaprolactone to form more microcrystalline areas during the cooling process, accelerate the cooling and curing of the material, and improve the mechanical strength. In the process of external force stretching, the regular microcrystalline area polycaprolactone molecular chains are neatly folded compared with the messy polycaprolactone molecular chains in the few microcrystalline areas when microcrystalline cellulose is not added. The same volume of folded and arranged polycaprolactone molecular chains are more, It has more and longer straightening space when stretched by external force, so the elongation at break of the test sample of Example 3 after adding microcrystalline cellulose will be greater; according to the test results of Example 3 and Comparative Example 5, it can be seen that not adding tributyl citrate will significantly increase the melting temperature of the composite material by 1°C, and according to the results of its melt index, it can be seen that not adding tributyl citrate will significantly reduce the melt index of the composite material, so the combination of these two factors will cause the prepared printing wire to have slow or unsmooth discharge during the printing process; according to the test results of Example 3 and Comparative Example 6, it can be seen that not adding diatomaceous earth powder, Although the melting temperature is reduced and the melting index is increased, the cooling and solidification time is greatly increased, and the tensile strength and bending strength are significantly reduced; the CCK-8 experimental method is used to test that the materials of Examples 1-6 and Comparative Examples 1-7 are not cytotoxic, and compared with the existing printing consumables on the market in Comparative Example 8, it is more or less slightly toxic or low toxic due to the addition of multiple additives or certain modifications, and the antibacterial effect is not obvious, which also shows that the composite material of the present invention has good safety performance, will not produce adverse side effects to children or users after contact, and can be used with peace of mind; in addition, the Figure 2 and Figure 3 The electron microscope photo clearly shows that pure Australian tea tree powder ( Figure 2 ) It can be seen that the powder is relatively messy and in the form of short strips of fibers, while the Australian tea tree powder is modified and prepared into composite particles with chitosan oligosaccharides ( Figure 3) is significantly more regular and spherical or micro-spherical compared to pure Australian tea tree powder, which makes it easier to disperse and mix evenly in the composite material.

[0099] The above embodiments are part of the preferred implementation methods of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing Australian tea tree composite microspheres, characterized in that: The following steps are involved: (1) cutting the branches of the Australian tea tree into small pieces or segments, baking until dry, and then crushing and sieving to obtain Australian tea tree powder; (2) adding the obtained Australian tea tree powder to the modified solution and dispersing it evenly, first subjecting it to ultrasonic treatment, then stirring and reacting it at 50-70°C for 3-8h, then keeping stirring and cooling it to room temperature, filtering, washing, drying, refining, and sieving to obtain modified Australian tea tree powder; The modified solution in step (2) is an ethanol solution with a modifier concentration of 3-8 wt%, and the pH value is adjusted to 8-9, and the modifier is a composition of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, diethylenetriamine and ammonium dodecylbenzenesulfonate, wherein the mass ratio of the three is (2-10): (0.1-0.5): (1-3); (3) preparing an aqueous solution with a total concentration of polyvinyl alcohol and polyvinyl pyrrolidone of 2.5-3.5 wt%; preparing an aqueous solution with a concentration of chitosan oligosaccharide of 1-2 wt%; and then mixing the two aqueous solutions evenly to obtain a mixed solution; wherein the weight ratio of the aqueous solution of polyvinyl alcohol and polyvinyl pyrrolidone to the aqueous solution of chitosan oligosaccharide is (1-5):(1-10); (4) adding the modified Australian tea tree powder into the mixed solution and dispersing it evenly, preparing powder particles through a spray drying process, drying, refining, and sieving to obtain Australian tea tree composite microspheres.

2. The preparation method according to claim 1, characterized in that: The Australian tea tree trunks in step (1) are produced in Ruyuan Yao Autonomous County of Shaoguan City or Wengyuan County of Shaoguan City, and are waste branches of Australian tea trees that have been extracted with essential oil or Australian tea tree trunks that have not been extracted with essential oil.

3. The preparation method according to claim 1, characterized in that: In step (2), the weight ratio of the content of the modifier in the modified solution to the Australian tea tree powder used is 1:(1-10).

4. The preparation method according to claim 1, characterized in that: In step (3), the weight ratio of polyvinyl alcohol to polyvinyl pyrrolidone is (4-10): (1-5), and the molecular weight of chitosan oligosaccharide is 500-5000.

5. The preparation method according to claim 1, characterized in that: The spray drying process control in step (4) is as follows: the inlet temperature is 103°C, the outlet temperature is 70°C, and the frequency of the sprayer is between 20-40 Hz.

6. The preparation method according to claim 1, characterized in that: The weight ratio of the modified Australian tea tree powder to the mixed solution used in step (4) is 1:(10-100).

7. A method for preparing an Australian tea tree 3D printing composite material, characterized in that: The following steps are involved: (i) 5-30 parts by weight of the Australian tea tree composite microspheres obtained by the preparation method of any one of claims 1 to 6, 0.1-1 parts by weight of microcrystalline cellulose, 0.2-2 parts by weight of diatomaceous earth powder and 0.1-2 parts by weight of calcium carbonate are mixed uniformly to obtain a mixed powder A for standby use; 0.5-2 parts by weight of tributyl citrate is added to 65-90 parts by weight of polycaprolactone and mixed uniformly, and then the obtained mixed powder A is added, and mixing is continued until uniform to obtain a mixture B; (ii) adding the mixture B into a twin-screw extruder for melt mixing, extrusion, cooling, pelletizing, and drying to obtain polycaprolactone composite pellets; (iii) adding the obtained polycaprolactone composite pellets into a single screw extruder for melt extrusion, drawing, cooling, air-drying, and collecting the wires to obtain the Australian tea tree 3D printing composite material.

8. The preparation method according to claim 7, characterized in that: The temperature settings of the twin-screw extruder are: 60°C in zone 1, 65°C in zone 2, 71°C in zone 3, 68°C in zone 4, 65°C in zone 5, and 63°C in the die zone. The twin-screw speed is 32 r / min, and the pelletizing speed is 12.4 r / min.

9. The preparation method according to claim 7, characterized in that: The single screw temperature was set as: 90°C in zone 1, 98°C in zone 2, 95°C in zone 3, and 91°C in die head zone, and the single screw speed was 25 r / min.

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