Matt PETG / PCL material for FDM printing and preparation method thereof

Abstract

The invention discloses a matte PETG / PCL material for FDM printing and a preparation method thereof, according to the matte PETG / PCL material, a frosted layer is formed on the surface of PETG by using micro-foaming and a small amount of extinction powder, meanwhile, the light transmittance is reduced, and a PETG product with a matte effect can be printed; pCL is used for reducing the melt strength of a PETG material, bubbles in a printing model can be effectively reduced and eliminated, the mechanical property of the printing model is improved in cooperation with ultrasonic treatment, and compared with an existing technology of adding high-filling extinction powder, the strength of the printing model can be improved to a certain degree; compared with a matte PETG model obtained through a high filling method, the matte PETG model printed through the method has the advantages that the printing appearance is better, and the problems of material shortage and plug blockage in the printing process can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, in particular to a matte PETG / PCL material for FDM printing and a preparation method thereof. Background Art

[0002] PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol) is a material with very high gloss and is widely used in FDM 3D printing. However, the models printed with PETG are very shiny, which many customers are dissatisfied with. They hope that PETG can be de-glossed and PETG models can be printed with a matte effect. At the same time, they require that the printed appearance of matte PETG is similar to that of ordinary PETG.

[0003] In the prior art, matte PETG materials are generally prepared by adding matte powders such as talcum powder, aluminum oxide, titanium dioxide, mica powder, and silicon dioxide to PETG. For example, in Chinese patent document CN115073891A, a high-filling method is used to prepare matte masterbatch for PET. PETG has very high brightness. To reduce the gloss, a large amount of matte additives needs to be added. However, after adding a large amount of matte powder, various performances during printing will deteriorate: (1) The mechanical properties of the printed PETG model will be significantly reduced; (2) At the same time, due to the dispersion problem of inorganic powders, the problem of material shortage and blockage during printing will also be very obvious; (3) The appearance of the print will deteriorate, such as the phenomenon of collapse when printing bridges.

[0004] Chinese patent document CN110481003A discloses an ultrasonic vibration-assisted 3D printing method. It uses a special ultrasonic vibration-assisted 3D printing device to perform ultrasonic vibration on materials that have not been fully solidified. After repeated layer-by-layer printing, high-performance 3D-printed parts with few pores and good bonding between phases, lines, and layers are formed. However, it does not involve improvements to the printing materials, and its mechanical properties cannot be guaranteed. Summary of the Invention

[0005] The present invention provides a matte PETG / PCL material for FDM printing and a preparation method thereof, which is used to solve the problems of poor printing appearance and easy blockage when printing due to lack of material in the prior art, while improving the mechanical properties of the printed model.

[0006] In view of this, the solution of the present invention is: The first aspect of the present invention is to provide a matte PETG / PCL material for FDM printing, which comprises 75-85 parts by mass of PETG, 10-20 parts by mass of PCL, 2-5 parts by mass of matting powder, 0.1-1 part by mass of foaming agent, 0.2-1 part by mass of lubricant, and 0.2-1 part by mass of antioxidant.

[0007] Furthermore, the matting powder is selected from at least one of silicon dioxide and titanium dioxide.

[0008] Furthermore, the foaming agent is selected from at least one of azodicarbonamide, p-toluenesulfonyl semicarbazide or expandable microspheres.

[0009] Furthermore, the lubricant is polyethylene wax.

[0010] Furthermore, the antioxidant is antioxidant 168.

[0011] The second aspect of the present invention is to provide a method for preparing a matte PETG / PCL filament for FDM printing, comprising mixing the components of the matte PETG / PCL material described in the first aspect, plasticizing and granulating to obtain PETG particles, and then drawing to obtain the matte PETG / PCL filament.

[0012] Furthermore, the extrusion temperature of the plasticizing and granulating process is 220-230°C; and / or the extrusion temperature of the wire drawing process is 210-230°C.

[0013] The third aspect of the present invention is to provide the use of the matte PETG / PCL material described in the first aspect or the matte PETG / PCL wire obtained by the preparation method described in the second aspect in FDM printing.

[0014] A fourth aspect of the present invention is to provide a matte product obtained by FDM printing of a matte PETG / PCL wire under ultrasonic conditions; the matte PETG / PCL wire is prepared by the preparation method described in the second aspect.

[0015] Furthermore, the printing temperature is 230-260° C.; and / or the ultrasonic frequency is 20-80 kHz, preferably 30-60 kHz, and more preferably 50 kHz.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The matte PETG / PCL material of the present invention forms a frosted layer on the PETG surface by using micro-foaming and a small amount of matting powder, while reducing the light transmittance, so that PETG products with a matte effect can be printed; PCL is used to reduce the melt strength of the PETG material, which is more conducive to effectively reducing and eliminating bubbles in the printed model, and cooperates with ultrasonic treatment to increase the mechanical properties of the printed model. Compared with the current technology of adding high-filling matting powder, the strength of the printed model will be improved to a certain extent; the matte PETG model printed by this method has a better printed appearance than the matte PETG model printed by the high-filling method, and can also solve the problem of material shortage and clogging during printing, while having a small weight reduction effect. DETAILED DESCRIPTION

[0017] The technical solutions of the present invention will be clearly and completely described below in conjunction with preferred embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] In one embodiment, a method for preparing a molded product by FDM printing of matte PETG / PCL filament is provided, comprising: 1. Preparation of matte PETG granules: The PETG granules are made from a PETG / PCL material. By total weight, the components are 75-85 parts PETG, 10-20 parts PCL, 2-5 parts matting agent, 0.1-1 part foaming agent, 0.2-1 part lubricant, and 0.2-1 part antioxidant. The formulated amount of PETG, PCL, foaming agent, and other raw materials are mixed together. The mixture is plasticized and granulated using a twin-screw extruder at a processing temperature of 220-230°C to produce matte PETG granules. 2. Wire drawing: The matte PETG particles in step 1 are subjected to wire drawing by a single screw extruder to obtain matte PETG filaments with a diameter of 1.75 mm for FDM printing, wherein the processing temperature of the single screw extruder is 210-230°C; 3. Printing model products: Use matte PETG filament to print model products, printing temperature: 230-260℃, and perform ultrasonic treatment during the printing process.

[0019] In the above embodiment, PETG has micro-foaming when 3D printing the product model. The method of using micro-foaming and adding a small amount of matte powder to form a frosted layer on the PETG surface, while reducing the transmittance, can print PETG products with a matte effect; PCL has a low melt strength at high temperature. During the ultrasonic printing process, PCL is used to reduce the melt strength of the PETG material, which is more conducive to effectively reducing and eliminating the bubbles in the printed model and increasing the mechanical properties of the printed model. Compared with the current technology of adding high-filling matte powder, the strength of the printed model will be improved to a certain extent; the matte PETG model printed by this method has a better printed appearance than the matte PETG model printed by the high-filling method, and can also solve the problem of material shortage and clogging during printing; in addition, printing the matte PETG model by this method has a small weight reduction effect.

[0020] In a preferred embodiment, the foaming agent is selected from one or two or three of azodicarbonamide, p-toluenesulfonyl semicarbazide or expandable microspheres; the expandable microspheres are thermoplastic hollow polymer microspheres, which are composed of a thermoplastic polymer shell and an enclosed liquid alkane gas. Preferably, the high-temperature expandable microspheres have a foaming effect at a printing temperature of 230-260°C, such as Japan Fujikura Microsphere Yangba powder, which has a decomposition temperature of 240°C.

[0021] In a preferred embodiment, the matting powder is one or both of silicon dioxide and titanium dioxide; the lubricant is polyethylene wax; the antioxidant is antioxidant 168, and the frequency of the ultrasonic vibration is 20 to 80 kHz, preferably 30 to 60 kHz, and more preferably 50 kHz. After adding PCL, ultrasound helps to improve the mechanical strength of the printed part.

[0022] The following are preferred implementation examples. Unless otherwise specified, the raw materials and additives used in each embodiment and comparative example are all commercially available standard products, and the experimental methods used are means that are well-known to those skilled in the art.

[0023] Example 1

[0024] The PETG / PCL material comprises, by mass, 85 parts of PETG, 10 parts of PCL, 5 parts of silicon dioxide, 0.5 parts of p-toluenesulfonyl semicarbazide, 0.3 parts of polyethylene wax, and 0.3 parts of antioxidant 168.

[0025] The steps of FDM printing model products are as follows: 1. Take the formulated amount of PETG, PCL, foaming agent and other raw materials and mix them together. Then, mix and plasticize them through a twin-screw extruder and granulate them to obtain matte PETG particles. The processing temperature of the twin-screw extruder is 220-230°C. 2. Wire drawing: The matte PETG particles in step 1 are subjected to wire drawing by a single screw extruder to obtain matte PETG filaments with a diameter of 1.75 mm for FDM printing, wherein the processing temperature of the single screw extruder is 210-230°C; 3. Printing model products: Use matte PETG filament to print the model products, the printing temperature is: 230-260℃, and ultrasonic treatment is performed during the printing process, and the ultrasonic condition is 30 kHz.

[0026] Example 2

[0027] The PETG / PCL material comprises, by mass, 80 parts of PETG, 15 parts of PCL, 5 parts of silicon dioxide, 0.5 parts of azodicarbonamide, 0.3 parts of polyethylene wax, and 0.3 parts of antioxidant 168.

[0028] The process steps for printing the model product using the FDM method are the same as those in Example 1, except that the ultrasonic frequency is 50 kHz.

[0029] Example 3

[0030] PETG / PCL material, the components by mass are 80 parts of PETG, 15 parts of PCL, 5 parts of silicon dioxide, 0.5 parts of Microsphere yangbuck powder, 0.3 parts of polyethylene wax, and 0.3 parts of antioxidant 168.

[0031] The process steps for printing the model product using the FDM method are the same as those in Example 1, except that the ultrasonic frequency is 60 kHz.

[0032] Example 4

[0033] The PETG / PCL material comprises, by mass, 78 parts of PETG, 18 parts of PCL, 3 parts of titanium dioxide, 0.6 parts of p-toluenesulfonyl semicarbazide, 0.3 parts of polyethylene wax, and 0.3 parts of antioxidant 168.

[0034] The process steps for printing the model product by FDM method are the same as those in Example 1.

[0035] The settings of Comparative Examples 1-8 are as shown in Table 1. Except for the different formulations and parameters shown in the table, the process steps of FDM printing the model product are the same as those of Example 1.

[0036] Table 1:

[0037] Test Case

[0038] The data of the above embodiments and comparative examples were all printed by FDM method to form test models. The performance test methods and standards are as follows: (1) Printed part glossiness: The printed model glossiness test was conducted with reference to the national standard GB / T 8807-1988. The measurement angle was 60°. A cube model was printed using an FDM printer. The surface glossiness of the model was tested at a printing speed of 100 mm / s. (2) Tensile strength of printed parts (MPa): The tensile strength of the printed strips was tested according to the GB / T 1040 standard, with a test condition of 50 mm / min. The printed model was a standard tensile strip of GB / T 1040. The strips were printed in the Z-axis direction at a printing speed of 20 mm / s. (3) 3D printed model appearance test: The appearance of the 3D printed model follows the classic FDM bridge test model, observing the 30mm collapse, and the printing speed is 100mm / s; (4) Density of printed parts: The density method is tested according to GB / T 1033 standard, and the test condition is 23°C; the printed specimens are bending strength specimens, and the bending strength test refers to the national standard GB / T 9341-2008, and the printing speed is 100 mm / s.

[0039] The above printing tests all used an FDM printer to print the specimens with a fill density of 100%, a printing temperature of 250°C, and a base plate temperature of 70°C.

[0040] The performance test results of the printed parts are shown in Table 2.

[0041] Table 2:

[0042] It is not difficult to see from Table 2 that the glossiness of the model parts obtained by printing in Examples 1-4 presents an obvious matte effect, and the 30mm bridge has basically no collapse, and there is no material shortage or clogging during the printing process, and the printed parts have high tensile strength.

[0043] Comparative Examples 1 and 2 employ high-filling matting powder technology, using a formula commonly used in conventional PETG matting technology. The difference is that ultrasound was not used during the printing process of the model in Comparative Example 2. As can be clearly seen from the performance results shown in Table 2, the mechanical properties and printed appearance of the PETG printed parts of Example 1 are superior to those of Comparative Examples 1 and 2. The matting effect of the two is similar, but Example 1 does not experience material shortage or blockage. Comparative Example 2 also reveals that even with ultrasound during the conventional matte PETG printing process, the tensile strength of the printed parts is not significantly improved.

[0044] The difference between Comparative Example 3 and Example 1 is that no ultrasonic treatment was performed during the printing of the model in Comparative Example 3. It can be seen that without ultrasonic treatment during the printing of the model, the tensile strength of the printed model will be significantly reduced.

[0045] The difference between Comparative Example 4 and Example 1 is that no foaming agent is added in Comparative Example 4, and the brightness of the printed model is significantly increased.

[0046] Comparative Example 5 is a conventional PETG material. Compared with ordinary PETG, the matte effect of the PETG printed model of Example 1 is obvious, the tensile strength of the printed model is less reduced, and there is no obvious difference in the printing effect.

[0047] The difference between Comparative Example 6 and Example 1 is that PCL is not added in Comparative Example 6, and the difference between Comparative Example 7 and Example 1 is that TPU is added instead of PCL. This shows that the addition of PCL helps to improve the mechanical strength of the printed part during the ultrasonic printing process of the printing model, while the use of other polymers is slightly less effective in increasing the strength, and even after ultrasonic treatment, the expected mechanical strength cannot be achieved.

[0048] The difference between Comparative Example 8 and Example 1 is that the ultrasonic frequency is increased during the model printing process in Comparative Example 8, but the printed appearance will deteriorate if the ultrasonic frequency is too high. For example, the 30mm bridge collapses significantly, indicating that the effect of the ultrasonic frequency on the printed appearance is not that the higher the frequency, the more suitable it is.

[0049] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Matte PETG / PCL material for FDM printing, characterized by: Calculated by mass, the components are 75-85 parts of PETG, 10-20 parts of PCL, 2-5 parts of matting powder, 0.1-1 part of foaming agent, 0.2-1 part of lubricant, and 0.2-1 part of antioxidant.

2. The matte PETG / PCL material according to claim 1, characterized in that The matting powder is selected from at least one of silicon dioxide and titanium dioxide.

3. The matte PETG / PCL material according to claim 1, characterized in that, The foaming agent is selected from at least one of azodicarbonamide, p-toluenesulfonyl semicarbazide or expandable microspheres.

4. The matte PETG / PCL material according to claim 1, characterized in that, The lubricant is polyethylene wax.

5. The matte PETG / PCL material according to claim 1, characterized in that, The antioxidant is antioxidant 168.

6. A method for preparing matte PETG / PCL filament for FDM printing, characterized in that: The components of the matte PETG / PCL material according to claim 1 are mixed evenly, plasticized and granulated to obtain PETG particles, and then drawn to obtain matte PETG / PCL wire.

7. The preparation method according to claim 6, characterized in that The extrusion temperature of the plasticizing and granulating process is 220-230°C; and / or the extrusion temperature of the wire drawing process is 210-230°C.

8. Use of the matte PETG / PCL material according to any one of claims 1 to 5 or the matte PETG / PCL filament obtained by the preparation method according to any one of claims 6 to 7 in FDM printing.

9. A matte product, characterized in that: The matte PETG / PCL wire is obtained by FDM printing under ultrasonic conditions; the matte PETG / PCL wire is obtained by the preparation method according to claim 6 or 7.

10. The matte product according to claim 9, characterized in that: The printing temperature is 230-260° C.; and / or the ultrasonic frequency is 20-80 kHz.

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