High-interlayer bonding force fiber reinforced pa6 modified material for 3d printing and preparation method thereof

Abstract

The application discloses a kind of high interlayer bonding force fiber reinforced PA6 modified materials for 3D printing and preparation method thereof, POE grafting maleic anhydride and silane coupling agent are used as layer adhesive, not only can make fiber evenly dispersed in PA6 matrix well, but also can well improve the interlayer bonding force of fiber reinforced PA6 material 3D printing piece, solve the problem of low interlayer bonding force of similar products on the market.The wire of the application has high interlayer bonding force, the tensile strength of Z axis is greater than 39MPa, and the printing process is smooth, no nozzle blocking occurs, ensuring the mechanical strength and appearance quality of the printed part.

Description

Technical Field

[0001] This invention relates to the field of 3D printing materials technology, and in particular to a high-layer interfacial bonding strength fiber-reinforced PA6 modified material for 3D printing and its preparation method. Background Technology

[0002] PA6 (polyamide 6) is an engineering plastic with high mechanical strength, high rigidity, and high heat resistance. Especially after being modified with glass fiber or carbon fiber reinforcement, it has even higher mechanical strength and rigidity, and its heat resistance can reach above 200℃. Therefore, it is widely used in the manufacture of automobiles, home appliances, machinery, electronic appliances and other products.

[0003] Glass fiber or carbon fiber reinforced PA6 materials are also used to prepare 3D printing filaments due to their high mechanical strength. However, the interlayer bonding strength of fiber-reinforced modified PA6 filament prints currently on the market is still relatively low (Z-axis tensile strength is generally <25MPa), which limits the application of this type of filament in fields that require high mechanical strength of the printed parts.

[0004] Chinese patent CN107652668A discloses a reinforced and toughened nylon material for 3D printing and its preparation method. The solution uses glass fibers to reduce the shrinkage rate of PA6, thus solving the problem of warping deformation of printed parts during printing. It employs toughening agents POE, EPDM, and SBS to improve the toughness of the glass fiber-reinforced PA6 matrix; maleic anhydride-grafted nylon polymers as compatibilizers to improve the compatibility between the toughening agents and the PA6 matrix; and maleic anhydride-grafted nylon polymers and silane coupling agents to improve the dispersibility of glass fibers in the PA6 matrix. The technical principle of this solution is mainly to utilize glass fibers to reduce the warping degree of PA6 during printing, thereby solving the problem of easy warping deformation in PA6 printing. The main functions of the compatibilizers and coupling agents are to improve the compatibility and dispersibility of the toughening agents and glass fibers with PA6, thus making filament printing smoother and preventing nozzle clogging. However, the solution did not mention or solve the problem of low interlayer bonding strength during the printing process of fiber-reinforced PA6 materials; it is precisely this low interlayer bonding strength that greatly limits its application areas, especially in the field of industrial products with high requirements for the mechanical properties of printed parts.

[0005] Therefore, developing a fiber-reinforced PA6 modified material with strong interlayer bonding for use in the 3D printing field is of great significance for broadening the application scenarios of this type of product. Summary of the Invention

[0006] To achieve the above objectives, this invention provides a fiber-reinforced PA6 modified material for high-layer interfacial bonding in 3D printing and its preparation method.

[0007] A first aspect of the present invention provides a fiber-reinforced PA6 modified material for interlayer bonding strength in 3D printing, comprising the following components by weight: 70-95 parts of PA6 resin 5-30 parts of reinforcing fiber 2-20 parts of adhesive Nucleating agent 0.2-2 parts 2-10 parts of inorganic filler 0.2-1.5 parts lubricant Antioxidant 0.2-2 parts There are no special requirements for the PA6 resin, but the preferred melt index (280℃, 2.16kg) is 10~50g / 10min.

[0008] When the melt index of PA6 resin is too low, it is not conducive to the dispersion of fibers in the PA6 resin matrix during material processing. At the same time, when the material is printed on a 3D printer, it is easy to cause insufficient material extrusion and failure to print. When the melt index of PA6 resin is too high, the fiber-reinforced PA6 modified material is prone to unstable wire diameter when drawing 3D printing filaments, and the filament is prone to stringing defects on the printed parts during printing.

[0009] The reinforcing fiber is one or more of glass fiber and carbon fiber, and the reinforcing fiber is preferably surface modified by polyurethane sizing agent, or polyamide sizing agent, or epoxy sizing agent, or silane sizing agent.

[0010] The adhesive is one or more of maleic anhydride-g-polyolefin elastomer (POE)-g-methacryloyloxypropyltrimethoxysilane, maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltrimethoxysilane, and maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane.

[0011] The principle behind the adhesive layer's ability to enhance interlayer bonding in this solution is as follows: POE in the adhesive molecular chain has excellent compatibility with the PA6 matrix, resulting in a strong physical entanglement between the POE and PA6 molecular chains. Furthermore, the maleic anhydride functional groups on the adhesive molecular chain react with the terminal amino groups on the PA6 molecular chain, chemically binding the adhesive molecular chain tightly to the PA6 molecular chain. The presence of polar silane molecular chains on the adhesive molecular chain increases the surface polarity of the PA6 matrix. During printing, the presence of these highly polar silane molecular chains strengthens the adhesion between printed layers, thus increasing interlayer bonding. Therefore, through the respective effects of maleic anhydride, POE, and silane molecular chains on the adhesive molecular chain, the adhesive layer effectively acts as a bridge between printed layers, enhancing the interlayer bonding of the printed parts.

[0012] Meanwhile, the initiator in the preparation of the laminar adhesive matrix can abstract hydrogen atoms from the POE molecular chain to form POE macromolecular free radicals. The POE macromolecular free radicals can initiate the opening of the double bonds on the maleic anhydride and silane coupling agent molecular chains, thereby grafting the maleic anhydride and silane coupling agent molecules onto the POE molecular chain. This part of the polymer is the main component of the maleic anhydride-grafted POE-grafted silane coupling agent in the laminar adhesive. In the main reaction described above, some POE macromolecular free radicals also combine with POE macromolecules grafted with maleic anhydride and silane coupling agents to form a network structure gel polymer that is insoluble in solvent. These network structure gel polymers also interweave between the printed layers during printing, further increasing the interlayer bonding force of the printed parts.

[0013] In this invention, the content of the network structure gel polymer is measured using a solvent extraction method.

[0014] The specific operating method is as follows: (1) Weigh approximately 2g of the prepared adhesive sample, and record the weight as follows: Take a piece of filter paper and weigh it, record the weight of the filter paper as m1, and wrap the sample with the filter paper.

[0015] (2) Place the filter paper containing the adhesive sample into a Soxhlet extractor containing about 150 ml of xylene, and heat it to boil the xylene for more than 5 hours.

[0016] (3) After extraction, remove the filter paper containing the sample and put it in a vacuum oven to dry to constant weight. After cooling, weigh the filter paper containing the sample and record it as m2.

[0017] (4) Calculate the gel content using the formula

[0018] Meanwhile, the maleic anhydride functional groups on the adhesive molecular chain and the silane molecules containing polar groups can further promote the uniform dispersion of reinforcing fibers in the PA6 matrix, thereby ensuring smooth printing of fiber-reinforced PA6 materials during 3D printing and preventing clogging of the printer nozzles.

[0019] The nucleating agent is one or more of organic phosphates and organic carboxylates.

[0020] The inorganic filler is one or more of calcium carbonate, talc, calcium sulfate whiskers, and montmorillonite, with a preferred particle size of 325 mesh to 4000 mesh, and the inorganic filler is preferably surface-modified.

[0021] The lubricant is one or more of calcium stearate, pentaerythritol stearate (PETS), and silicone powder.

[0022] The antioxidant is one or more of hindered phenolic antioxidants and phosphite antioxidants.

[0023] Secondly, the present invention provides a method for preparing the above-mentioned fiber-reinforced PA6 modified material for 3D printing, comprising the following steps: Step S1: Add POE resin and maleic anhydride to a high-speed mixer and mix at 500-2000 rpm for 5-10 minutes to obtain a solid mixture; Step S2: Add the silane coupling agent and initiator to a mixing tank and mix them evenly at room temperature to obtain a mixed liquid.

[0024] Step S3: The solid mixture in S1 is added through the main feed port of the twin-screw extruder using the main feeder, and the liquid mixture in S2 is added through the liquid feed port of the twin-screw extruder using the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80~150℃ and a screw speed of 300~400rpm. The material undergoes a grafting reaction during the extrusion process. The extrudate is then stretched, pelletized, and dried to obtain a binder.

[0025] Step S4: Weigh the remaining raw materials (excluding fibers) and the binder prepared in S3 according to the component ratio of the 3D printing interlayer bonding fiber-reinforced PA6 modified material, add them to a high-speed mixer, and mix at 800~2000 rpm for 5min~10min to obtain a mixture. Step S5: Add the mixture obtained in S4 to the main feeder of the twin-screw extruder. The raw material is added to the main feed port of the twin-screw extruder through the main feeder. The fiber material is added to the side feeder of the twin-screw extruder through the side feed port of the twin-screw extruder. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 350~600rpm to obtain the high-layer interfacial bonding strength fiber-reinforced PA6 modified material for 3D printing.

[0026] The present invention adopts the above technical solution and has the following technical effects compared with the prior art: This invention prepares a POE-grafted maleic anhydride and silane coupling agent as a layer binder, which can not only effectively disperse the fiber uniformly in the PA6 matrix, but also significantly improve the interlayer bonding force of fiber-reinforced PA6 3D printed parts. This solves the problem of low interlayer bonding force in similar products on the market and expands the application field of the product. Detailed Implementation

[0027] The present invention will now be described in detail and specifically through specific embodiments to enable a better understanding of the invention. However, the following embodiments do not limit the scope of the invention. Example 1

[0028] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 96.5 parts of POE resin and 2 parts of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: Add 1 part of methacryloyloxypropyltrimethoxysilane and 0.5 parts of the initiator tert-amyl peroxide-2-ethylhexyl carbonate to a stirring tank and mix evenly at room temperature to obtain a mixed liquid.

[0029] Step S3: The solid mixture from S1 is added through the main feed port of the twin-screw extruder using the main feeder; the liquid mixture from S2 is added through the liquid feed port of the twin-screw extruder using the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80-150℃ and a screw speed of 300-400 rpm. During the extrusion process, the material undergoes a grafting reaction. The extrudate is then stretched, pelletized, and dried to obtain the adhesive maleic anhydride-g-polyolefin elastomer (POE)-g-methacryloyloxypropyltrimethoxysilane; wherein the content of the network structure gel polymer in the adhesive is 0.8%.

[0030] Step S4: Weigh 70 parts of PA6 resin (melt index 48 g / 10 min, 280℃, 2.16 kg), 20 parts of laminator maleic anhydride-g-polyolefin elastomer (POE)-g-methacryloyloxypropyltrimethoxysilane, 0.2 parts of organophosphate nucleating agent NA-11 (supplier: Adico), 2 parts of calcium carbonate (4000 mesh, surface treated with stearic acid), 1.5 parts of lubricant calcium stearate, 0.5 parts of hindered phenolic antioxidant 1098, and 0.3 parts of phosphite antioxidant P-EPQ (supplier: Clariant) according to the component ratio of the 3D printing interlayer bonding fiber reinforced PA6 modified material. Add them to a high-speed mixer and mix at 800 rpm for 10 min to obtain a mixture. Step S5: Add the mixture obtained in S4 to the main feeder of the twin-screw extruder. The raw material is added to the main feed port through the main feeder of the twin-screw extruder. Add 30 parts of glass fiber that has been surface modified with polyurethane sizing agent to the side feeder of the twin-screw extruder and add it to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 350rpm to obtain a high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0031] The 3D printing filament was prepared as follows for printing performance testing.

[0032] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Example 2

[0033] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 96.2 parts of POE resin and 1.5 parts of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: Add 1.5 parts of vinyltrimethoxysilane and 0.8 parts of initiator 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane to a stirring tank and mix evenly at room temperature to obtain a mixed liquid.

[0034] Step S3: The solid mixture from S1 is added through the main feed port of the twin-screw extruder using the main feeder; the liquid mixture from S2 is added through the liquid feed port of the twin-screw extruder using the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80-150℃ and a screw speed of 300-400 rpm. During the extrusion process, the material undergoes a grafting reaction. The extrudate is then stretched, pelletized, and dried to obtain the adhesive maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltrimethoxysilane; wherein the content of the network structure gel polymer in the adhesive is 1%.

[0035] Step S4: Weigh 80 parts of PA6 resin (melt index 30g / 10min, 280℃, 2.16kg), 10 parts of laminator maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltrimethoxysilane, 0.8 parts of organophosphate nucleating agent NA-21 (supplier: Adico), 10 parts of calcium sulfate whiskers (3000 mesh, surface treated with silane coupling agent), 1 part of lubricant PETS, 0.8 parts of hindered phenolic antioxidant 3114, and 0.6 parts of phosphite antioxidant Revonox 608 into a high-speed mixer and mix at 2000rpm for 5min to obtain a mixture. Step S5: Add the mixture obtained in S4 to the main feeder of the twin-screw extruder. The raw material is added to the main feed port through the main feeder of the twin-screw extruder. Add 20 parts of glass fiber that has been surface modified with polyamide sizing agent to the side feeder of the twin-screw extruder and add it to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 600rpm to obtain a high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0036] The 3D printing filament was prepared as follows for printing performance testing.

[0037] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Example 3

[0038] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 96 parts of POE resin and 1 part of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: Add 2 parts of vinyltriethoxysilane and 1 part of initiator tert-butyl peroxide-2-ethylhexyl carbonate to a mixing tank and mix evenly at room temperature to obtain a mixed liquid.

[0039] Step S3: The solid mixture from S1 is added through the main feed port of the twin-screw extruder using the main feeder; the liquid mixture from S2 is added through the liquid feed port of the twin-screw extruder using the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80-150℃ and a screw speed of 300-400 rpm. During the extrusion process, the material undergoes a grafting reaction. The extrudate is then stretched, pelletized, and dried to obtain the adhesive maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane; wherein the content of the network structure gel polymer in the adhesive is 1.5%.

[0040] Step S4: Weigh 95 parts of PA6 resin (melt index 12g / 10min, 280℃, 2.16kg), 2 parts of laminator maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane, 2 parts of organic carboxylate nucleating agent Licomont NaV 101 (supplier: Clariant), 5 parts of talc powder (325 mesh, surface treated with silane coupling agent), 0.2 parts of lubricant silicone powder, and 0.2 parts of hindered phenolic antioxidant 1010 into a high-speed mixer and mix at 1500rpm for 8min to obtain a mixture. Step S5: Add the mixture obtained in S4 to the main feeder of the twin-screw extruder. The raw material is added to the main feed port through the main feeder of the twin-screw extruder. Add 5 parts of carbon fiber that has been surface modified with epoxy sizing agent to the side feeder of the twin-screw extruder and add it to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 450rpm to obtain the high-layer interfacial bonding strength fiber-reinforced PA6 modified material for 3D printing.

[0041] The 3D printing filament was prepared as follows for printing performance testing.

[0042] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Example 4

[0043] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 96 parts of POE resin and 1 part of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: Add 2 parts of vinyltriethoxysilane and 1 part of initiator tert-butyl peroxide-2-ethylhexyl carbonate to a mixing tank and mix evenly at room temperature to obtain a mixed liquid.

[0044] Step S3: The solid mixture from S1 is added through the main feed port of the twin-screw extruder using the main feeder; the liquid mixture from S2 is added through the liquid feed port of the twin-screw extruder using the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80-150℃ and a screw speed of 300-400 rpm. During the extrusion process, the material undergoes a grafting reaction. The extrudate is then stretched, pelletized, and dried to obtain the adhesive maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane; wherein the content of the network structure gel polymer in the adhesive is 1.5%.

[0045] Step S4: Weigh out 75 parts of PA6 resin (melt index 48g / 10min, 280℃, 2.16kg), 5 parts of laminator maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane, 1 part of organic carboxylate nucleating agent KL-102 (supplier: Guangzhou Yongjiu Fine Chemical Co., Ltd.), 3 parts of montmorillonite (2000 mesh, surface treated with silane coupling agent), 0.5 parts of lubricant silicone powder, 1 part of hindered phenolic antioxidant CYANOX 1790 (supplier: Guangzhou Haorui New Materials Co., Ltd.), and 0.5 parts of phosphite antioxidant 168 into a high-speed mixer and mix at 1000rpm for 8min to obtain a mixture. Step S5: Add the mixture obtained in S4 to the main feeder of the twin-screw extruder. The raw materials are added to the main feed port through the main feeder of the twin-screw extruder. 20 parts of glass fiber with surface modification treatment by silane coupling agent sizing agent and 5 parts of carbon fiber with surface modification treatment by polyurethane sizing agent are added to the side feeder of the twin-screw extruder and added to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 500rpm to obtain the high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0046] The 3D printing filament was prepared as follows for printing performance testing.

[0047] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Comparative Example 1

[0048] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps:

[0049] Step S1: Weigh 75 parts of PA6 resin (melt index 48g / 10min, 280℃, 2.16kg), 1 part of organic carboxylate nucleating agent KL-102 (supplier: Guangzhou Yongjiu Fine Chemical Co., Ltd.), 3 parts of montmorillonite (2000 mesh, surface treated with silane coupling agent), 0.5 parts of lubricant silicone powder, 1 part of hindered phenolic antioxidant CYANOX 1790 (supplier: Guangzhou Haorui New Materials Co., Ltd.), and 0.5 parts of phosphite antioxidant 168 into a high-speed mixer and mix at 1000rpm for 8min to obtain a mixture. Step S2: Add the mixture obtained in S1 to the main feeder of the twin-screw extruder. The raw materials are added to the main feed port through the main feeder of the twin-screw extruder. 20 parts of glass fiber with surface modification by silane coupling agent sizing agent and 5 parts of carbon fiber with surface modification by polyurethane sizing agent are added to the side feeder of the twin-screw extruder and added to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 500rpm to obtain a high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0050] The 3D printing filament was prepared as follows for printing performance testing.

[0051] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Comparative Example 2

[0052] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 98 parts of POE resin and 1 part of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: The solid mixture in S1 is added from the main feed port of the twin-screw extruder through the main feeder. One part of liquid initiator 2-ethylhexyl tert-butyl peroxide is added from the liquid feed port of the twin-screw extruder through the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80~150℃ and a screw speed of 300~400rpm. The material undergoes a grafting reaction during the extrusion process. The extrudate is stretched, pelletized, and dried to obtain the adhesive polyolefin elastomer (POE)-g-maleic anhydride.

[0053] Step S3: Weigh 75 parts of PA6 resin (melt index 48 g / 10 min, 280℃, 2.16 kg), 5 parts of laminator polyolefin elastomer (POE)-g-maleic anhydride, 1 part of organic carboxylate nucleating agent KL-102 (supplier: Guangzhou Yongjiu Fine Chemical Co., Ltd.), 3 parts of montmorillonite (2000 mesh, surface treated with silane coupling agent), 0.5 parts of lubricant silicone powder, 1 part of hindered phenolic antioxidant CYANOX 1790 (supplier: Guangzhou Haorui New Materials Co., Ltd.), and 0.5 parts of phosphite antioxidant 168 into a high-speed mixer and mix at 1000 rpm for 8 min to obtain a mixture. Step S4: Add the mixture obtained in S3 to the main feeder of the twin-screw extruder. The raw materials are added to the main feed port through the main feeder of the twin-screw extruder. 20 parts of glass fiber with surface modification treatment by silane coupling agent sizing agent and 5 parts of carbon fiber with surface modification treatment by polyurethane sizing agent are added to the side feeder of the twin-screw extruder and added to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 500rpm to obtain the high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0054] The 3D printing filament was prepared as follows for printing performance testing.

[0055] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm. Comparative Example 3

[0056] This embodiment provides a PA6 modified material with interlayer bonding strength fiber for 3D printing, and its preparation method specifically includes the following steps: Step S1: Add 98 parts of POE resin and 1 part of maleic anhydride to a high-speed mixer and mix at 500~2000 rpm for 5~10 min to obtain a solid mixture; Step S2: The solid mixture in S1 is added from the main feed port of the twin-screw extruder through the main feeder. One part of liquid initiator 2-ethylhexyl tert-butyl peroxide is added from the liquid feed port of the twin-screw extruder through the liquid feeder. The twin-screw extruder is melt-extruded at a temperature of 80~150℃ and a screw speed of 300~400rpm. The material undergoes a grafting reaction during the extrusion process. The extrudate is stretched, pelletized, and dried to obtain the adhesive polyolefin elastomer (POE)-g-maleic anhydride.

[0057] Step S3: Weigh out 75 parts of PA6 resin (melt index 48 g / 10 min, 280℃, 2.16 kg), 5 parts of laminator polyolefin elastomer (POE)-g-maleic anhydride, 1 part of organic carboxylate nucleating agent KL-102 (supplier: Guangzhou Yongjiu Fine Chemical Co., Ltd.), 3 parts of montmorillonite (2000 mesh, surface treated with silane coupling agent), 0.5 parts of lubricant silicone powder, 1 part of hindered phenolic antioxidant CYANOX 1790 (supplier: Guangzhou Haorui New Materials Co., Ltd.), 0.5 parts of phosphite antioxidant 168, and 0.5 parts of vinyltriethoxysilane into a high-speed mixer and mix at 1000 rpm for 8 min to obtain a mixture. Step S4: Add the mixture obtained in S3 to the main feeder of the twin-screw extruder. The raw materials are added to the main feed port through the main feeder of the twin-screw extruder. 20 parts of glass fiber with surface modification treatment by silane coupling agent sizing agent and 5 parts of carbon fiber with surface modification treatment by polyurethane sizing agent are added to the side feeder of the twin-screw extruder and added to the twin-screw extruder through the side feed port. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 500rpm to obtain the high-layer interfacial bonding fiber-reinforced PA6 modified material for 3D printing.

[0058] The 3D printing filament was prepared as follows for printing performance testing.

[0059] The obtained PA6 modified material with interlayer bonding strength fiber for 3D printing was added to a 3D printing filament extruder and melted and plasticized at a temperature of 230℃~250℃ to draw 3D printing filament for printing tests. The filament diameter was 1.75mm.

[0060] Performance testing standards: The printing process conditions for interlayer bonding strength test strips are as follows: Print a rectangular spline with a length × width × thickness of 150mm × 20mm × 4mm according to the model. The printer nozzle temperature is 290℃, the sparse infill density is 100%, and the infill method is a straight line.

[0061] The test results of the filament printing performance prepared by the modified materials in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1: Example 1 43 Printing is smooth and the nozzles do not clog. Example 2 32 Printing is smooth and the nozzles do not clog. Example 3 30 Printing is smooth and the nozzles do not clog. Example 4 39 Printing is smooth and the nozzles do not clog. Comparative Example 1 20 Printing is not smooth, and nozzles are clogged. Comparative Example 2 22 Printing is smooth and the nozzles do not clog. Comparative Example 3 23 Printing is smooth and the nozzles do not clog. .

[0062] As can be seen from Table 1, the wire-printed test pieces prepared by the modified material obtained by this scheme have high Z-axis tensile strength and high interlayer bonding force. At the same time, the wire printing process is smooth and there is no nozzle clogging, thus ensuring the mechanical strength and appearance quality of the printed parts.

[0063] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A fiber-reinforced PA6 modified material for interlayer bonding strength in 3D printing, comprising the following components by weight: 70-95 parts of PA6 resin 5-30 parts of reinforcing fiber 2-20 parts of adhesive Nucleating agent 0.2-2 parts 2-10 parts of inorganic filler 0.2-1.5 parts lubricant Antioxidant 0.2-2 parts The adhesive is one or more of maleic anhydride-g-polyolefin elastomer (POE)-g-methacryloyloxypropyltrimethoxysilane, maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltrimethoxysilane, and maleic anhydride-g-polyolefin elastomer (POE)-g-vinyltriethoxysilane.

2. The PA6 modified material according to claim 1, characterized in that: The melt index (280℃, 2.16kg) of the PA6 resin is 10~50g / 10min.

3. The PA6 modified material according to claim 1, characterized in that: The nucleating agent is one or more of organic phosphates and organic carboxylates.

4. The PA6 modified material according to claim 1, characterized in that: The inorganic filler is one or more of calcium carbonate, talc, calcium sulfate whiskers, and montmorillonite.

5. The PA6 modified material according to claim 1, characterized in that: The lubricant is one or more of calcium stearate, pentaerythritol stearate (PETS), and silicone powder. The antioxidant is one or more of hindered phenolic antioxidants and phosphite antioxidants.

6. A fiber-reinforced PA6 modified material for high-layer interlayer bonding strength in 3D printing, comprising the following steps: Step S1: Add the polyolefin elastomer and maleic anhydride to a high-speed mixer and mix at 500-2000 rpm for 5-10 minutes to obtain a solid mixture; Step S2: Add the silane coupling agent and initiator to a stirring tank and mix them evenly at room temperature to obtain a mixed liquid; Step S3: The solid mixture in S1 is added through the main feeder of the twin-screw extruder from the main feed port, and the liquid mixture in S2 is added through the liquid feeder of the twin-screw extruder from the liquid feed port. The twin-screw extruder is melt-extruded at a temperature of 80~150℃ and a screw speed of 300~400rpm. The material undergoes a grafting reaction during the extrusion process. The extrudate is then stretched, pelletized, and dried to obtain a binder. Step S4: Weigh the remaining raw materials except for the fiber according to the component ratio of the 3D printing interlayer bonding strength fiber-reinforced PA6 modified material according to any one of claims 1-5, add them to a high-speed mixer, and mix at 800~2000 rpm for 5min~10min to obtain a mixture; Step S5: Add the mixture obtained in S4 to the main feed port of the twin-screw extruder, and add the fiber material to the side feed port of the twin-screw extruder. All materials are melted, plasticized, mixed, extruded, pelletized and dried at a temperature of 220℃~250℃ and a twin-screw extruder speed of 350~600rpm to obtain the high-layer interfacial bonding strength fiber-reinforced PA6 modified material for 3D printing.

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