High-strength high-temperature-resistant carbon fiber reinforced PET (polyethylene terephthalate) consumable, preparation method thereof and application in 3D (three-dimensional) printing

Abstract

The invention discloses a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable, a preparation method thereof and application in 3D printing, the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable is prepared by mixing a carbon fiber reinforced PET master batch and a PET thermal crosslinking master batch, crosslinking is not generated in the consumable preparation process, the consumable can quickly react when being applied to 3D printing at high temperature, and the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable can be used for 3D printing. Further, the Z-axis tensile strength, the thermal deformation temperature and other mechanical properties of the material are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable, a preparation method thereof, and an application in 3D printing. Background Art

[0002] When carbon fiber-reinforced PET is currently used in 3D printing, it's difficult to achieve both high heat resistance and high Z-axis strength due to the 3D printing process. Chinese patent document CN107974053A discloses a carbon fiber-reinforced PET composition and its preparation method. By combining hollow glass microspheres with a surface modifier, the composition improves the surface fiber floating after injection molding and enhances the compressive strength of the glass fiber-reinforced PET composition. However, the addition of carbon fibers and glass microspheres results in rapid crystallization and poor interlayer bonding strength. Chinese patent document CN104419136A discloses a carbon fiber reinforced PET / ABS alloy, in which the carbon fiber is a carbon fiber whose surface is modified with polyacrylonitrile. Specifically, the carbon fiber is soaked in a polyacrylonitrile solution, and the soaked carbon fiber is pre-oxidized in an oven at 50°C to 300°C for 0.1 to 100 hours and dried to obtain surface-modified carbon fiber, thereby improving the specific strength of the carbon fiber reinforced PET / ABS alloy. However, due to the incompatibility between PET and ABS, the material has average heat resistance and is prone to warping. Summary of the Invention

[0003] The present invention provides a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable material to improve the Z-axis tensile strength, heat deformation temperature and other mechanical properties of 3D printing materials.

[0004] In view of this, the solution of the present invention is: The first aspect of the present invention is to provide a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable material, which is obtained by mixing carbon fiber reinforced PET masterbatch and PET high-temperature thermal cross-linking masterbatch and then co-extruding; wherein: The carbon fiber reinforced PET masterbatch is composed of 1060 parts of PET, 10-50 parts of carbon fiber, 0.1-5 parts of nucleating agent, 0.1-5 parts of chain extender, 0.2-0.4 parts of antioxidant and 510 parts of surface improver. The PET high-temperature thermal cross-linking masterbatch is composed of 80-90 parts by mass of low-temperature PET, 0.1-2 parts by mass of a high-temperature cross-linking agent, 0.2-0.4 parts by mass of an antioxidant, and 0.5-3 parts by mass of a lubricant. The high-temperature cross-linking agent is a cross-linking agent that cross-links with PET to form a carbamate bond or urea bond ring structure.

[0005] Furthermore, the mass proportion of the PET high-temperature thermal cross-linking masterbatch is 30-70%.

[0006] Furthermore, the melting point of the high-temperature crosslinking agent is above 150° C., and the product obtained after reacting with PET is a PET thermal crosslinking agent with a temperature resistance of 280-320° C. Preferably, the high-temperature thermal crosslinking initiator is a polyisocyanate, such as hexamethylene diisocyanate.

[0007] Furthermore, the viscosity of the PET is 0.9-1.2 dL / g, and the melting point is 240-260°C; and / or the viscosity of the low-temperature PET is 0.6-0.7 dL / g, and the melting point is 170-180°C.

[0008] Furthermore, the nucleating agent includes a sodium benzoate derivative nucleating agent and a polyether crystallization accelerator; and / or, the chain extender is ADR 4468; And / or, the antioxidant is at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol and bis(2,4-di-tert-butylphenyl)pentaerythritol bisdiphosphite; And / or, the surface improver is a high-temperature-resistant dendritic structure resin grafted siloxane with a molecular weight of more than 100,000; And / or, the lubricant is pentaerythritol stearate.

[0009] The second aspect of the present invention is to provide a method for preparing the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable material described in the first aspect, comprising the following steps: After mixing the components of carbon fiber reinforced PET masterbatch, extrude at 240-270℃; and, drying the extruded carbon fiber reinforced PET masterbatch and the PET high temperature cross-linked masterbatch to remove moisture in steps or simultaneously; The extruded carbon fiber reinforced PET masterbatch and PET high temperature thermal cross-linking masterbatch are mixed in proportion and then co-extruded at 240-250°C to obtain high-strength and high-temperature-resistant carbon fiber reinforced PET consumables.

[0010] Furthermore, the moisture content of the material is controlled to be less than 0.1% during the baking process; And / or, the co-extrusion process frequency is 25-45 Hz, the hot water tank temperature is 80-90° C., and the cold water tank temperature is room temperature.

[0011] The third aspect of the present invention is to propose the use of the high-strength and high-temperature-resistant carbon fiber reinforced PET consumables described in the first aspect in the preparation of 3D printed products.

[0012] The fourth aspect of the present invention is to provide a 3D printed product, which is obtained by 3D printing the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable described in the first aspect or the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable obtained by the preparation method described in the second aspect; the 3D printing temperature is 280-310°C.

[0013] Furthermore, during the 3D printing process: The bottom plate temperature is 70-100℃; and / or, the printing speed is set to 50-300 mm / s; and / or, a filling density of 15-100%.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable provided by the present invention is prepared by mixing carbon fiber reinforced PET masterbatch with PET thermal cross-linking masterbatch. No cross-linking occurs during the preparation of the consumable. The consumable can react quickly when used in 3D printing at high temperatures, thereby improving the material's Z-axis tensile strength, heat deformation temperature and other mechanical properties. DETAILED DESCRIPTION

[0015] 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.

[0016] In one embodiment, a method for preparing a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable for 3D printing is provided, comprising the following steps: 1. Drying: First, mix 30-70 parts of PET thermal cross-linking masterbatch and 30-70 parts of carbon fiber reinforced masterbatch evenly. Bake the mixture at 120℃ for 5-7 hours. The moisture content of the baked mixture measured at 105℃ is ≤0.1%; The carbon fiber reinforced masterbatch 1060 parts of PET, 10-50 parts of carbon fiber, 0.15 parts of nucleating agent, 0.1-5 parts of chain extender, 0.2-0.4 parts of antioxidant and 0.310 parts of surface improver are mixed in a high-speed mixer for 3-5 minutes and modified in a twin-screw at 240-270°C to obtain the obtained product; The PET high-temperature thermal crosslinking masterbatch comprises the following components by mass fraction: 80-90 parts of low-temperature PET, 0.1-2 parts of high-temperature crosslinking initiator, 0.2-0.4 parts of antioxidant, and 0.5-3 parts of lubricant. The preparation method of the PET high-temperature thermal crosslinking masterbatch is as follows: 1) Dry low-temperature PET at 80 degrees Celsius for 2-4 small tests, and the moisture content is less than or equal to 0.08%; 2) Add 0.5-3 parts of lubricant and 0.2-0.4 parts of antioxidant to the dried low-temperature PET, mix well, and put into the internal mixer. Start from 220℃ and mix while cooling for 3 minutes. After the temperature stabilizes to 200℃, add high-temperature crosslinking agent and mix for 1 minute. The high-temperature crosslinking agent reacts with the end groups (hydroxyl or carboxyl) of PET to form a carbamate bond or urea bond ring structure between the molecular weight of PET. Extrude and pelletize to obtain PET thermal crosslinking masterbatch; 3) After the carbon fiber reinforced PET masterbatch and the thermal cross-linked masterbatch are dried and mixed in proportion, a high-strength and high-temperature-resistant carbon fiber reinforced PET consumable material with cross-linking during the 3D printing process can be extruded using a single screw; 2. Preparation of consumables A: The carbon fiber reinforced PET masterbatch and PET high-temperature cross-linked masterbatch that have been dried and have qualified moisture content are mixed evenly and plasticized into a wire through a single-screw extruder. The wire diameter and roundness are controlled by passing through cold and hot water tanks to obtain consumables A. The extrusion temperature is 240-250℃, the extrusion frequency is 25-45Hz, the hot water tank temperature is 80-90℃, and the cold water tank temperature is room temperature.

[0017] In the above embodiment, the PET thermal cross-linking masterbatch is processed using low-temperature PET. The cross-linking agent is evenly dispersed and does not react during the granulation process, which ensures the material's later processing performance and also prepares for the improvement of the Z-axis interlayer tensile strength of 3D printing in the later stage. The existing technology uses PET-CF with a low carbon fiber content. A higher carbon fiber content will lead to defects such as stress fracture during the production of consumables. In this solution, carbon fiber reinforced masterbatch is used. PET carbon fiber masterbatch is used to reduce the reduction in the performance of PET-CF consumables caused by twin-screw shearing, and the heat resistance temperature of the PET-CF consumable printing model is increased by adding high modulus carbon fiber and nucleating agent. After the carbon fiber reinforced PET masterbatch and PET high-temperature thermal cross-linking masterbatch are mixed and extruded in a single screw, low-temperature PET is used. The processing temperature is lower than 260°C. The reaction temperature of the cross-linking agent is not reached during the extrusion process, so that the cross-linking effect in the produced carbon fiber reinforced PET consumable is not reflected. By twin-screw processing of carbon fiber reinforced PET masterbatch and PET thermal cross-linking masterbatch separately, the processing temperature can be effectively controlled to prevent shear heat from raising the melt temperature and causing the cross-linking agent to react prematurely. Ultimately, the temperature is high during 3D printing, and the melt is heated in the cavity for a short time. The high-temperature cross-linking agent can react quickly, improving the material's Z-axis tensile strength, heat deformation temperature and other mechanical properties.

[0018] In a preferred embodiment, the PET has a viscosity of 0.9-1.2 dL / g and a melting point of 240-260°C (eg, China Resources 8829); the low-temperature PET has a viscosity of 0.6-0.7 dL / g and a melting point of 175°C (eg, Reda PET-20).

[0019] In a preferred embodiment, the high-temperature thermal crosslinking agent has a melting point above 150°C, and the resulting product after reaction with PET is heat-resistant to 280-320°C. Preferably, the high-temperature thermal crosslinking initiator is a polyisocyanate, such as hexamethylene diisocyanate (HDI), which reacts with the terminal groups (hydroxyl or carboxyl) of PET to form urethane or urea bonds, thereby extending the PET molecular chain.

[0020] In a preferred embodiment, the carbon fiber is imported ADR T800 carbon fiber. The nucleating agent is preferably a mixture of a sodium benzoate derivative (Nu) nucleating agent (NO₂HF) and a polyether crystallization accelerator (INO₂), with a mass ratio of 1:2 between the polyester nucleating agent NO₂HF and the crystallization accelerator INO₂. The chain extender is preferably ADR 4468. The surface modifier is a high-temperature-resistant dendritic resin grafted with siloxane (such as Weihai Chenyuan CYD-FS102A) with a molecular weight of 100,000 or higher. The hyperbranching enhances the material's internal and external lubrication, improves its fluidity, and enhances surface smoothness, preventing glass fiber exposure. The grafted siloxane improves surface scratch resistance and enhances the additive's high-temperature resistance. The antioxidant is a mixture of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1010) and bis(2,4-di-tert-butylphenyl)pentaerythritol bisdiphosphite (antioxidant 626) in a mass ratio of 1:2; the lubricant is pentaerythritol stearate.

[0021] In the above-mentioned embodiments, the PET consumables obtained by the preparation method can significantly improve the material's Z-axis tensile strength, heat distortion temperature, and other mechanical properties when used in 3D printing. Preferred 3D printing conditions are 280-310°C, a base plate temperature of 70-100°C, a printing speed of 50-300 mm / s, a packing density of 15-100%, and a fan speed of 10-100%. At the printing temperature, the crosslinking agent reacts with the PET end groups (hydroxyl or carboxyl groups) to form urethane or urea bonds, thereby extending the PET molecular chain and improving the material's properties.

[0022] The following are preferred implementation examples. Unless otherwise specified, the reagents used are commercially available reagents in the field, and the means used are means that are well-known to those skilled in the art.

[0023] The components of the preparation example of carbon fiber reinforced PET masterbatch are shown in Table 1.

[0024] Table 1:

[0025] The components of the above carbon fiber reinforced PET masterbatch were mixed for 3-5 minutes respectively, and then granulated by twin-screw extrusion at 240-270° C. to obtain carbon fiber reinforced PET masterbatch.

[0026] The components of the PET high-temperature thermal cross-linking masterbatch of Examples 1-5 are shown in Table 2.

[0027] Table 2:

[0028] Among them, PET high temperature thermal cross-linking masterbatch is prepared as follows: 1) Dry low-temperature PET at 80 degrees Celsius for 2-4 small tests, and the moisture content is less than or equal to 0.08%; 2) Add 0.5-3 parts of lubricant and 0.2-0.4 parts of antioxidant to the dried low-temperature PET, mix well, and put it into the internal mixer. Start mixing from 220℃ while cooling and mixing for 3 minutes. After the temperature stabilizes at 200℃, add the high-temperature crosslinking agent and mix for 1 minute. Extrude and pelletize to obtain PET thermal crosslinking masterbatch.

[0029] The preparation example of high-strength and high-temperature-resistant carbon fiber reinforced PET consumables is as follows: Example 1 50 parts of carbon fiber reinforced PET masterbatch A1 and 50 parts of PET high-temperature thermal crosslinking masterbatch B1. The dried carbon fiber reinforced PET masterbatch and PET high-temperature thermal crosslinking masterbatch are mixed evenly and passed through a single-screw extruder to plasticize and draw a wire. The wire diameter and roundness are controlled by passing through cold and hot water tanks to obtain consumables A. The extrusion temperature is 240-250°C, the extrusion frequency is 25-45Hz, the hot water tank temperature is 80-90°C, and the cold water tank temperature is room temperature.

[0030] Example 2

[0031] 50 parts of carbon fiber reinforced PET masterbatch A2 and 50 parts of PET high temperature thermal crosslinking masterbatch B2. The preparation process of high strength and high temperature resistant carbon fiber reinforced PET consumables is the same as that of Example 1.

[0032] Example 3

[0033] 40 parts of carbon fiber reinforced PET masterbatch A1 and 60 parts of PET high temperature crosslinking masterbatch B3. The preparation process of high strength and high temperature resistant carbon fiber reinforced PET consumables is the same as that of Example 1.

[0034] Example 4

[0035] 60 parts of carbon fiber reinforced PET masterbatch A3 and 40 parts of PET high temperature crosslinking masterbatch B1. The preparation process of high strength and high temperature resistant carbon fiber reinforced PET consumables is the same as that of Example 1.

[0036] Comparative Example 1

[0037] 50 parts of carbon fiber reinforced PET masterbatch A1 and 50 parts of PET high temperature crosslinking masterbatch B4. The preparation process of PET consumables is the same as that of Example 1.

[0038] Comparative Example 2

[0039] 100 parts of carbon fiber reinforced PET masterbatch A1, without adding PET high temperature heat crosslinking masterbatch. PET consumables preparation process: The carbon fiber reinforced PET masterbatch was directly plasticized and drawn into a wire by a single screw extruder according to Example 1.

[0040] Comparative Example 3

[0041] 100 parts of PET high-temperature thermal crosslinking masterbatch B1, without adding carbon fiber reinforced PET masterbatch. PET consumables preparation process: The PET high-temperature thermal crosslinking masterbatch was directly plasticized and drawn into a wire by a single-screw extruder according to Example 1.

[0042] Experimental example

[0043] Tested according to GB / T 1033 standard, test conditions 23℃; Melt index: tested according to GB / T 3682 standard, test conditions 300℃ / 1.2Kg; Tensile strength and elongation at break: tested in accordance with GB / T 1040 standard, test conditions 50mm / min; Flexural strength and flexural modulus: tested according to GB / T 9341 standard, test conditions 5mm / min; Heat deformation temperature: tested according to GB / T 1634 standard, test conditions 0.45MPa, 120℃ / h; 3D printing conditions: 280-310℃, base plate temperature 70-100℃, printing speed 50-300mm / s, filling density 15-100%, fan 10-100%.

[0044] The above Examples 1-4 and Comparative Examples 1-3 were 3D printed, and their related properties are shown in Table 4.

[0045] Table 4:

[0046] The high-strength and high-temperature-resistant carbon fiber reinforced PET consumables prepared in Examples 1-4 for 3D printing have the characteristics of meeting the requirements of a printing speed of 200 mm / s and a maximum volume flow rate of 20 mm / s for smooth printing.3 / s, ultra-high inter-layer strength (printing Z-axis tensile strength 37.4MPa), high temperature resistance (printing 0.45MPa heat deformation temperature 148.6℃), no cracking, little drawing (drawing less than 10mm), good toughness (printing notch impact strength reaches 7.16KJ / m 2 ) and other performance.

[0047] The PET high-temperature thermal crosslinking masterbatch in Comparative Example 1 lacks a high-temperature thermal crosslinking agent, so it cannot react with the PET end groups at high printing temperatures. The direct use of carbon fiber-reinforced PET masterbatch in Comparative Example 2 and Comparative Example 3 both reduced mechanical properties such as Z-axis interlaminar strength and toughness to varying degrees, and the printing appearance and smoothness were also affected to varying degrees. This shows that the use of PET thermal crosslinking masterbatch synergistically improves the Z-axis interlaminar strength of high-strength, high-temperature-resistant carbon fiber-reinforced PET consumables. By adjusting the addition ratio of each component in the formula, a high-strength, high-temperature-resistant carbon fiber-reinforced PET consumable with the optimal ratio of each component is obtained, resulting in the best overall printing performance.

[0048] 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. High-strength and high-temperature-resistant carbon fiber reinforced PET consumables, characterized by: It is obtained by mixing carbon fiber reinforced PET masterbatch and PET high temperature thermal cross-linking masterbatch and then co-extruded; wherein: The carbon fiber reinforced PET masterbatch is composed of 1060 parts of PET, 10-50 parts of carbon fiber, 0.1-5 parts of nucleating agent, 0.1-5 parts of chain extender, 0.2-0.4 parts of antioxidant and 510 parts of surface improver. The PET high-temperature thermal cross-linking masterbatch is composed of 80-90 parts by mass of low-temperature PET, 0.1-2 parts by mass of a high-temperature cross-linking agent, 0.2-0.4 parts by mass of an antioxidant, and 0.5-3 parts by mass of a lubricant. The high-temperature cross-linking agent is a cross-linking agent that cross-links with PET to form a carbamate bond or urea bond ring structure.

2. The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to claim 1, characterized in that: The mass proportion of the PET high-temperature thermal cross-linking masterbatch is 30-70%.

3. The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to claim 1, characterized in that: The melting point of the high-temperature crosslinking agent is above 150° C., and the product obtained after reacting with PET is a PET thermal crosslinking agent with a temperature resistance of 280-320° C.

4. The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to claim 3, characterized in that: The high-temperature heat-crosslinking masterbatch is obtained by mixing low-temperature PET, an antioxidant, and a lubricant, kneading them, adding a high-temperature crosslinking agent, continuing kneading and reacting, and then extruding and pelletizing.

5. The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to claim 1, characterized in that: The PET has a viscosity of 0.9-1.2 dL / g and a melting point of 240-260°C; And / or, the low-temperature PET has a viscosity of 0.6-0.7 dL / g and a melting point of 170-180°C.

6. The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to claim 1, characterized in that: The nucleating agent includes a sodium benzoate derivative nucleating agent and a polyether crystallization accelerator; and / or, the chain extender is ADR 4468; And / or, the antioxidant is at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol and bis(2,4-di-tert-butylphenyl)pentaerythritol bisdiphosphite; And / or, the surface improver is a high-temperature-resistant dendritic structure resin grafted siloxane with a molecular weight of more than 100,000; And / or, the lubricant is pentaerythritol stearate.

7. The method for preparing the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable material according to claim 1, characterized in that the steps include: After mixing the components of carbon fiber reinforced PET masterbatch, extrude at 240-270℃; and, drying the extruded carbon fiber reinforced PET masterbatch and the PET high temperature cross-linked masterbatch to remove moisture in steps or simultaneously; The extruded carbon fiber reinforced PET masterbatch and PET high temperature thermal cross-linking masterbatch are mixed in proportion and then extruded at 240-250°C to obtain high-strength and high-temperature-resistant carbon fiber reinforced PET consumables.

8. Use of the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to any one of claims 1 to 6 in the preparation of 3D printed products.

9. A 3D printed product, characterized in that: The high-strength and high-temperature-resistant carbon fiber reinforced PET consumable according to any one of claims 1 to 6 or the high-strength and high-temperature-resistant carbon fiber reinforced PET consumable obtained by the preparation method according to claim 7 is obtained by 3D printing; the 3D printing temperature is 280-310°C.

10. The 3D printed product according to claim 9, characterized in that: The base plate temperature during the 3D printing process is 70-100°C; and / or, the printing speed is set to 50-300 mm / s; and / or, a filling density of 15-100%.

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