Modified polylactic acid material applied to high-speed 3D printing and preparation method thereof

Abstract

The invention discloses a modified polylactic acid material applied to high-speed 3D printing and a preparation method of the modified polylactic acid material. The modified polylactic acid material comprises the following components in parts by weight: 50-80 parts of a polylactic acid material, 10-30 parts of inorganic powder, 1-10 parts of a toughening agent, 0.1-0.5 part of a coupling agent, 0.1-0.4 part of a hindered phenol antioxidant, 0.1-0.4 part of a phosphite antioxidant and 0.2-0.6 part of a plasticizer. The invention has the following beneficial effects: PLA with different flowability is compounded as a base material and is blended with inorganic powder, so that the printing speed of the material reaches 500mm / s, and excellent printability of high precision, no wiredrawing and layer grain covering is achieved; the coupling agent is introduced into a system of the PLA and the inorganic powder, so that the surface polarity of the inorganic powder is improved, the inorganic powder has good compatibility with a resin matrix, and the interlayer adhesive force and the mechanical property of the material are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of modified polylactic acid material preparation, and in particular to a modified polylactic acid material applied to high-speed 3D printing and a preparation method thereof. Background Art

[0002] Additive manufacturing technology, also known as 3D printing, uses digital model files to print materials layer by layer, simplifying the manufacturing process and reducing production and R&D costs. As a novel manufacturing method, it is gradually being applied to medical, automotive, aerospace and other fields. Fused deposition modeling (FDM) is the most widely used 3D printing technology. FDM technology has low equipment cost and stable material product size. Currently, thermoplastic resins are generally used for printing and molding, including polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), PETG material, nylon (PA), polycarbonate (PC) and other materials. As a representative material of degradable plastics, polylactic acid (PLA) has attracted special attention in recent years. PLA has excellent properties such as low melting temperature, low shrinkage and low water absorption, making it the most widely used material in the field of FDM printing.

[0003] With the gradual launch of high-speed FDM 3D printers, FDM printing has gradually become a rising star in the mass manufacturing industry, but the slow printing speed is an important reason that limits its application in mass manufacturing. Currently, the fastest FDM printing material is PLA, which is only 250mm / s. The printing speed is slow, and the surface glossiness of PLA material is high during high-speed printing, making its layer pattern obvious, which cannot meet the requirements of mass manufacturing. Therefore, a modified polylactic acid material and its preparation method for high-speed 3D printing are designed. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and to design a modified polylactic acid material and a preparation method thereof for high-speed 3D printing.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is a modified polylactic acid material used for high-speed 3D printing, comprising the following components in parts by weight: 50-80 parts of polylactic acid material, 10-30 parts of inorganic powder, 1-10 parts of toughening agent, 0.1-0.5 parts of coupling agent, 0.1-0.4 parts of hindered phenol antioxidant, 0.1-0.4 parts of phosphite antioxidant, and 0.2-0.6 parts of plasticizer.

[0006] As a further description of the technical solution, the melt mass flow rate of the polylactic acid material at a temperature of 190° C. and a pressure of 2.16 kg is in the range of 5-40 g / 10 min.

[0007] As a further description of the technical solution, the inorganic powder is one or more of talc powder, calcium carbonate, mica powder, and glass microspheres.

[0008] As a further description of the present technical solution, the toughening agent is preferably one or more of polybutylene terephthalate adipate (PBAT), polybutylene succinate (PBS), ethylene-acrylate-glycidyl methacrylate, methyl methacrylate-butadiene-styrene terpolymer, ethylene-butyl acrylate copolymer, and maleic anhydride grafted POE.

[0009] As a further description of the technical solution, the coupling agent is one or more of a silane coupling agent and an aluminate coupling agent.

[0010] As a further description of the technical solution, the hindered phenol antioxidant is one or more of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.

[0011] As a further description of the technical solution, the phosphite antioxidant is one or more of bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite, tris[2,4-di-tert-butylphenyl]phosphite, and poly(dipropylene glycol)phenyl phosphite.

[0012] As a further description of the technical solution, the plasticizer is one or more of epoxidized soybean oil, polyethylene glycol, citric acid fatty acid glycerin.

[0013] A method for preparing a modified polylactic acid material for high-speed 3D printing comprises the following steps:

[0014] Step 1: Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0015] Step 2: weighing PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stirring the weighed components at a speed of 100-600r / min for 5-20min to obtain a prefabricated raw material;

[0016] Step 3: adding the prefabricated raw materials into a twin-screw extruder for extrusion granulation to obtain modified pellets, and the temperatures of the zones of the twin-screw extruder are set in sequence as follows: zone 1 150-180°C, zone 2 160-190°C, zone 3 170-200°C, zone 4 180-205°C, zone 5 180-205°C, zone 6 180-205°C, zone 7 185-210°C, zone 8 185-210°C, zone 9 190-215°C, zone 10 190-215°C, zone 11 190-215°C, die head 190-215°C, main engine speed 200-500r / min, feeding frequency 5-15r / min;

[0017] Step 4: Bake the modified pellets at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then add the dried pellets into a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: Zone 1 160-180°C, Zone 2 180-210°C, Zone 3 180-210°C, Zone 4 185-215°C, Zone 5 185-215°C, Zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before performing a printing test.

[0018] The beneficial effects are as follows: 1. The present invention uses a compound of PLA with different fluidities as the matrix material to improve the material fluidity, cooling rate and mechanical properties.

[0019] 2. The present invention uses PLA to blend with inorganic powders of different particle sizes to increase the material flow rate, so that the material printing speed reaches 500 mm / s, and the inorganic powders with small particle size and high mesh count will act as a nucleating agent, accelerate the cooling and crystallization rate of PLA, and reduce the drawing fluff of the model printing.

[0020] 3. The present invention uses PLA and inorganic powder to compound, the surface has a matte texture, and can effectively cover the layer texture under high-speed printing.

[0021] 4. The present invention uses different types of toughening agents, which can be evenly dispersed in PLA, giving full play to their toughening effect on PLA and improving the impact strength of PLA materials.

[0022] 5. In the present invention, a phosphite antioxidant and a hindered phenol antioxidant are added to the PLA resin for use in combination. The compounded antioxidants complement each other in terms of anti-oxidation, thereby preventing oxidation of the material.

[0023] 6. The present invention introduces a coupling agent into the system of PLA and inorganic powder to improve the surface polarity of the inorganic powder, so that it has good compatibility with the resin matrix, and the interlayer adhesion and mechanical properties of the material are further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is an S-type printing speed measurement model diagram of the present invention;

[0025] Figure 2 It is the wire drawing test model of the present invention. DETAILED DESCRIPTION

[0026] First of all, the original intention of the design of the present invention is explained. With the gradual listing of high-speed FDM 3D printers, FDM printing has gradually become a rising star in the mass manufacturing industry, but the current slow printing speed is an important reason that limits its application in mass manufacturing. At present, the material with the fastest FDM printing speed is PLA, which is only 250mm / s, and the printing speed is slow. In addition, during the high-speed printing process, the surface gloss of the PLA material is high, making its layer pattern obvious, and it cannot meet the requirements of mass manufacturing. Therefore, the present invention designs a modified polylactic acid material and a preparation method thereof for high-speed 3D printing.

[0027] The present invention will be described in detail below. A modified polylactic acid material for high-speed 3D printing includes the following components in parts by weight: 50-80 parts of polylactic acid (PLA) material, 10-30 parts of inorganic powder, 1-10 parts of toughening agent, 0.1-0.5 parts of coupling agent, 0.1-0.4 parts of hindered phenol antioxidant, 0.1-0.4 parts of phosphite antioxidant, and 0.2-0.6 parts of plasticizer.

[0028] Wherein, the melt mass flow rate of the polylactic acid material at a temperature of 190° C. and a pressure of 2.16 kg is in the range of 5-40 g / 10 min.

[0029] The inorganic powder is one or more of talcum powder, calcium carbonate, mica powder and glass microspheres.

[0030] The toughening agent is preferably one or more of polybutylene terephthalate adipate (PBAT), polybutylene succinate (PBS), ethylene-acrylate-glycidyl methacrylate, terpolymer of methyl methacrylate-butadiene-styrene, ethylene-butyl acrylate copolymer, and maleic anhydride grafted POE.

[0031] The coupling agent is one or more of a silane coupling agent and an aluminate coupling agent.

[0032] The hindered phenol antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.

[0033] The phosphite antioxidant is one or more of bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite, tris[2,4-di-tert-butylphenyl]phosphite and poly(dipropylene glycol)phenylphosphite.

[0034] The plasticizer is one or more of epoxidized soybean oil, polyethylene glycol, citric acid, fatty acid and glycerin.

[0035] The following is a detailed introduction to the preparation method of modified polylactic acid material for high-speed 3D printing, including the following steps:

[0036] Step 1: Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0037] Step 2: weighing PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stirring the weighed components at a speed of 100-600r / min for 5-20min to obtain a prefabricated raw material;

[0038] Step 3: adding the prefabricated raw materials into a twin-screw extruder for extrusion granulation to obtain modified pellets, and the temperatures of the zones of the twin-screw extruder are set in sequence as follows: zone 1 150-180°C, zone 2 160-190°C, zone 3 170-200°C, zone 4 180-205°C, zone 5 180-205°C, zone 6 180-205°C, zone 7 185-210°C, zone 8 185-210°C, zone 9 190-215°C, zone 10 190-215°C, zone 11 190-215°C, die head 190-215°C, main engine speed 200-500r / min, feeding frequency 5-15r / min;

[0039] Step 4: Bake the modified pellets at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then add the dried pellets into a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: Zone 1 160-180°C, Zone 2 180-210°C, Zone 3 180-210°C, Zone 4 185-215°C, Zone 5 185-215°C, Zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before performing a printing test.

[0040] The present technical solution will be described in detail below in conjunction with the embodiments and comparative examples:

[0041] Example 1

[0042] The modified polylactic acid material used in this example for high-speed 3D printing comprises the following components in parts by weight: 30 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of PLA material (brand name L105, produced by Total Company), 30 parts of inorganic powder talc (brand name HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of hindered phenol antioxidant, 0.3 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0043] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0044] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0045] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0046] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0047] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0048] Example 2

[0049] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 30 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of PLA material (brand name L105, produced by Total Company), 30 parts of inorganic powder talc (brand name HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0050] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0051] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0052] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0053] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0054] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0055] Example 3

[0056] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 30 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of PLA material (brand name L105, produced by Total Company), 30 parts of inorganic powder talc (brand name HS-538, 1500 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0057] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0058] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0059] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0060] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0061] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0062] Example 4

[0063] The modified polylactic acid material used in this example for high-speed 3D printing comprises the following components in parts by weight: 30 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of PLA material (brand name L105, produced by Total Company), 30 parts of inorganic powder talc (brand name HS-538, 1500 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent ethylene-methyl acrylate grafted methacrylate glycidyl ester copolymer (brand name AX8900, produced by Dow Chemical), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0064] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0065] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0066] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0067] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0068] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0069] Example 5

[0070] The modified polylactic acid material used in this example for high-speed 3D printing comprises the following components in parts by weight: 30 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of PLA material (brand name L105, produced by Total Company), 30 parts of inorganic powder talc (brand name HS-538, 1500 mesh, produced by Guangyuan Chemical Company), 4.5 parts of toughening agent ethylene-methyl acrylate grafted methacrylate glycidyl ester copolymer (brand name AX8900, produced by Dow Chemical), 4.5 parts of toughening agent methyl methacrylate-butadiene-styrene terpolymer (brand name EM500, produced by Dow Chemical), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0071] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0072] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0073] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0074] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0075] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0076] Comparative Example 1

[0077] The modified polylactic acid material used in this example for high-speed 3D printing comprises the following components in parts by weight: 45 parts of PLA material (brand name REVODE110, produced by Hisun Company), 45 parts of PLA material (brand name L105, produced by Total Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0078] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0079] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0080] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0081] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0082] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0083] Comparative Example 2

[0084] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 40 parts of PLA material (brand name REVODE110, produced by Hisun Company), 40 parts of PLA material (brand name L105, produced by Total Company), 10 parts of inorganic powder talc (brand name HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0085] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0086] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0087] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0088] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0089] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0090] Comparative Example 3

[0091] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 35 parts of PLA material (brand name REVODE110, produced by Hisun Company), 35 parts of PLA material (brand name L105, produced by Total Company), 20 parts of inorganic powder talc (brand name HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0092] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0093] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0094] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0095] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0096] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0097] Comparative Example 4

[0098] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 60 parts of PLA material (grade L105, produced by Total), 30 parts of inorganic powder talc (HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (grade KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0099] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0100] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0101] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0102] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0103] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0104] Comparative Example 5

[0105] The modified polylactic acid material used in this example for high-speed 3D printing contains the following components in parts by weight: 60 parts of PLA material (brand name REVODE110, produced by Hisun Company), 30 parts of inorganic powder talc (HS-218, 800 mesh, produced by Guangyuan Chemical Company), 9 parts of toughening agent PBAT (brand name KHB21AP11, produced by Kanghui Company), 0.3 parts of coupling agent, 0.15 parts of hindered phenol antioxidant, 0.15 parts of phosphite antioxidant, and 0.4 parts of plasticizer.

[0106] The method for preparing the polylactic acid material for high-speed 3D printing comprises the following steps:

[0107] Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use;

[0108] Weigh PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stir the weighed components at a speed of 100-600 r / min for 5-20 min to obtain a prefabricated raw material;

[0109] The prefabricated raw materials are added into a twin-screw extruder for extrusion granulation to obtain modified pellets. The temperatures of the zones of the twin-screw extruder are sequentially set as follows: 150-180°C for zone 1, 160-190°C for zone 2, 170-200°C for zone 3, 180-205°C for zone 4, 180-205°C for zone 5, 180-205°C for zone 6, 185-210°C for zone 7, 185-210°C for zone 8, 190-215°C for zone 9, 190-215°C for zone 10, 190-215°C for zone 11, die head 190-215°C, main engine speed 200-500r / min, and feeding frequency 5-15r / min;

[0110] The modified pellets are dried at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then the dried pellets are added to a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: zone 1 160-180°C, zone 2 180-210°C, zone 3 180-210°C, zone 4 185-215°C, zone 5 185-215°C, zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before a printing test.

[0111] The testing method of the material used in the present invention comprises the following steps:

[0112] The wires of Examples 1-5 and Comparative Examples 1-5 were tested by printing with an FDM 3D printer to check the printing speed, model effect, tensile strength in the XZ direction, and impact strength in the XY direction. The printing conditions were: print head temperature 220°C, base plate temperature 30-60°C, Sanhe 190 varnish sprayed on the base plate to increase the adhesion between the base plate and the printed part, and the printing speed was 250-500mm / s. The material printing speed was tested with an S-type speed measurement model, and the model integrity was observed after printing. The S-type curve speed model is as follows: Figure 1 As shown; the wire drawing model is used to measure the material cooling wire drawing ability and layer pattern performance, and the model integrity is observed after printing. The wire drawing model is as follows Figure 2 The printer prints dumbbell samples in accordance with the standard ISO 527 at a regular printing speed of 250 mm / s to test the tensile strength of the material in the XZ printing method, which characterizes the interlayer bonding ability of the material; the printer prints samples in accordance with the standard ISO179 at a regular printing speed of 250 mm / s to test the impact strength of the material in the XY printing method, which characterizes the toughness of the material. The test results are shown in Table 1.

[0113] Table 1 Effects and performance of wire printing of embodiments and comparative examples

[0114]

[0115]

[0116] By comparing the printing effect, XZ tensile strength, and XY impact strength, the following conclusions can be drawn:

[0117] From the printing effects of Comparative Examples 1-3 and Example 2, it can be seen that with the increase of talcum powder content, the printing speed, cooling capacity and layer coverage of PLA materials are improved accordingly. When the powder content reaches 30wt%, the printing speed reaches 500mm / s, the model has no wire drawing and the layer pattern is not obvious. However, the addition of large particle size and high content of powder has a negative impact on the interlayer adhesion and toughness of the material.

[0118] It can be seen from the printing effects of Examples 1 and 2 that the addition of coupling agent improves the interlayer adhesion and mechanical properties of the material. The coupling agent can improve the surface polarity of the inorganic powder and make it have good compatibility with the resin matrix.

[0119] From the printing effects of Examples 2 and 3, it can be seen that talcum powder with different particle sizes has a good modification on the cooling and flow rate of the material, but talcum powder with a small particle size has less effect on the continuous phase of the material, and the mechanical properties and interlayer adhesion of the material are higher.

[0120] It can be seen from the printing effects of Example 2 and Comparative Examples 4-5 that low- and high-fluidity PLA materials alone cannot simultaneously meet the requirements of high printing speed and high printing effect. By compounding PLA materials with different fluidities, both requirements can be met at the same time.

[0121] By comparing the printing effects of Examples 3-5, it can be seen that selecting the composite ratio of different toughening agents can effectively improve the toughness of the material.

[0122] The printing speed of the wire material printing process of Examples 1-5 of the present invention can reach 500mm / s; the layer pattern is not obvious, and the wire drawing printing effect is good; the impact strength is high and has good toughness; the tensile strength in the XZ direction is high and the interlayer bonding effect is good. The modified PLA material of the present invention can meet the requirements of high-speed printing and mass production.

[0123] The same effect can be achieved by using different powders, such as other brands or powders with lower particle sizes, and the printing speed can reach 500mm / s.

[0124] Using high-flow PLA may reduce the content of inorganic powder and the printing speed can reach 500mm / s.

[0125] 1. The present invention uses a compound of PLA with different fluidities as the matrix material to improve the material fluidity, cooling rate and mechanical properties.

[0126] 2. The present invention uses PLA to blend with inorganic powders of different particle sizes to increase the material flow rate, so that the material printing speed reaches 500 mm / s, and the inorganic powders with small particle size and high mesh count will act as a nucleating agent, accelerate the cooling and crystallization rate of PLA, and reduce the drawing fluff of the model printing.

[0127] 3. The present invention uses PLA and inorganic powder to compound, the surface has a matte texture, and can effectively cover the layer texture under high-speed printing.

[0128] 4. The present invention uses different types of toughening agents, which can be evenly dispersed in PLA, giving full play to their toughening effect on PLA and improving the impact strength of PLA materials.

[0129] 5. In the present invention, a phosphite antioxidant and a hindered phenol antioxidant are added to the PLA resin for use in combination. The compounded antioxidants complement each other in terms of anti-oxidation, thereby preventing oxidation of the material.

[0130] 6. The present invention introduces a coupling agent into the system of PLA and inorganic powder to improve the surface polarity of the inorganic powder, so that it has good compatibility with the resin matrix, and the interlayer adhesion and mechanical properties of the material are further improved.

[0131] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A modified polylactic acid material for high-speed 3D printing, characterized in that: The invention comprises the following components in parts by weight: 50-80 parts of polylactic acid material, 10-30 parts of inorganic powder, 1-10 parts of toughening agent, 0.1-0.5 parts of coupling agent, 0.1-0.4 parts of hindered phenol antioxidant, 0.1-0.4 parts of phosphite antioxidant and 0.2-0.6 parts of plasticizer.

2. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The melt mass flow rate of the polylactic acid material at a temperature of 190° C. and a pressure of 2.16 kg is in the range of 5-40 g / 10 min.

3. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The inorganic powder is one or more of talcum powder, calcium carbonate, mica powder and glass microspheres.

4. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The toughening agent is preferably one or more of polybutylene terephthalate adipate (PBAT), polybutylene succinate (PBS), ethylene-acrylate-glycidyl methacrylate, terpolymer of methyl methacrylate-butadiene-styrene, ethylene-butyl acrylate copolymer, and maleic anhydride grafted POE.

5. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The coupling agent is one or more of a silane coupling agent and an aluminate coupling agent.

6. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The hindered phenol antioxidant is one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.

7. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The phosphite antioxidant is one or more of bis(2,4-di-tert-butylphenol)pentaerythritol diphosphite, tris[2,4-di-tert-butylphenyl]phosphite and poly(dipropylene glycol)phenylphosphite.

8. The modified polylactic acid material for high-speed 3D printing according to claim 1, characterized in that: The plasticizer is one or more of epoxidized soybean oil, polyethylene glycol, citric acid, fatty acid and glycerin.

9. A method for preparing a modified polylactic acid material for high-speed 3D printing as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Bake PLA at 55-60°C until the moisture content is no more than 0.05%wt, and cool to room temperature for later use; Step 2: weighing PLA raw material, inorganic powder, toughening agent, coupling agent, hindered phenol antioxidant, phosphite antioxidant and plasticizer according to the formula ratio, and stirring the weighed components at a speed of 100-600r / min for 5-20min to obtain a prefabricated raw material; Step 3: adding the prefabricated raw materials into a twin-screw extruder for extrusion granulation to obtain modified pellets, and the temperatures of the zones of the twin-screw extruder are set in sequence as follows: zone 1 150-180°C, zone 2 160-190°C, zone 3 170-200°C, zone 4 180-205°C, zone 5 180-205°C, zone 6 180-205°C, zone 7 185-210°C, zone 8 185-210°C, zone 9 190-215°C, zone 10 190-215°C, zone 11 190-215°C, die head 190-215°C, main engine speed 200-500r / min, feeding frequency 5-15r / min; Step 4: Bake the modified pellets at 55-65°C until the moisture content does not exceed 0.05% to obtain dried pellets, and then add the dried pellets into a single-screw extruder to extrude the plastic melt. The temperatures of the heating zones of the single-screw extruder are set as follows: Zone 1 160-180°C, Zone 2 180-210°C, Zone 3 180-210°C, Zone 4 185-215°C, Zone 5 185-215°C, Zone 6 190-220°C, hot water temperature 55-70°C, cold water temperature 30-40°C, and the wire is dried before printing test.

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