Glass fiber reinforced polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a glass fiber reinforced polypropylene composite material and a preparation method and application thereof, and belongs to the technical field of 3D printing materials.The glass fiber reinforced polypropylene composite material is prepared by adding modified glass fibers into a traditional polypropylene material. In the large-size 3D printing process, it can be guaranteed that no obvious warping and cracking phenomena occur, the forming shrinkage rate is small, in the long-time printing process, the printing state does not need to be observed all the time through manpower, labor force is liberated, and good surface attractiveness and strength of a printed piece can be guaranteed; and compared with polylactic acid, acrylonitrile-butadiene-styrene copolymer and other materials, the polylactic acid / acrylonitrile-butadiene-styrene copolymer can be widely applied in the field of industrial production, and the cost of the polylactic acid / acrylonitrile-butadiene-styrene copolymer composite material is obviously reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing materials, and in particular to a glass fiber reinforced polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Additive manufacturing, also known as 3D printing, rapid manufacturing, or physical free-form fabrication, involves creating physical parts by adding material layer by layer using a CAD model. When 3D printing large parts, the initial printing process requires real-time monitoring and adjustment of the first layer, and the adhesion of the printing material to the platform needs to be improved.

[0003] During the printing process, existing printing materials like polypropylene are prone to warping, stress concentration, and cracking, significantly limiting their application in industrial production. Conventional solutions include improving the printing process and equipment. Optimizing the printing path can reduce stress concentration, but this requires operators to have strong structural design expertise and experience, and has limited repeatability. Alternatively, adjusting the chamber temperature can reduce warping, stress concentration, and cracking in the printed material, but this is difficult and costly to modify for large-scale 3D printing equipment. Summary of the Invention

[0004] The present invention provides a glass fiber reinforced polypropylene composite material and its preparation method and application, which effectively solves the technical problems of easy warping, stress concentration and cracking of printed materials in the current 3D printing process of parts. The present invention provides a glass fiber reinforced polypropylene composite material that effectively reduces the warping and cracking of large-sized 3D printed parts in an open environment at room temperature, ensures a certain degree of strength in use, and reduces costs.

[0005] The first object of the present invention is to provide a glass fiber reinforced polypropylene composite material, which is made from the following raw materials in parts by weight: 50 to 70 parts of random copolymer polypropylene, 10 to 30 parts of calcium carbonate masterbatch, 10 to 30 parts of modified glass fiber, 0.2 to 0.5 parts of anti-glass fiber exposure agent, and 0.5 to 1 parts of antioxidant.

[0006] As a preferred embodiment, the preparation method of the modified glass fiber is as follows: according to the dosage ratio of 0.8g to 1.2g:5mL, the glass fiber is immersed in a silane coupling agent ethanol solution with a mass concentration of 10% for 24 hours to obtain the modified glass fiber.

[0007] As a preferred embodiment, the random copolymer polypropylene contains 3% to 7% by mass of ethylene, and the random copolymer polypropylene is in the form of spherical particles of 2 mm to 3 mm.

[0008] As a preferred embodiment, the calcium carbonate content in the calcium carbonate masterbatch is 95% to 98%, and the particle size of the calcium carbonate masterbatch is 2 mm to 3 mm.

[0009] As a preferred embodiment, the silane coupling agent is vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, isobutyltriethoxysilane or isocyanate silane coupling agent.

[0010] As a preferred embodiment, the anti-glass fiber exposure agent is modified ethylene bis fatty acid amide and / or modified silicone; the antioxidant is antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and antioxidant 168 (tris[2,4-di-tert-butylphenyl] phosphite). The two antioxidants are used in combination to prevent the generation of free radicals, thermal decomposition of materials and yellowing of composite materials.

[0011] A second object of the present invention is to provide a method for preparing the above-mentioned glass fiber reinforced polypropylene composite material, comprising the following steps:

[0012] Weigh the following raw materials in parts by weight: 50-70 parts of random copolymer polypropylene, 10-30 parts of calcium carbonate masterbatch, 10-30 parts of modified glass fiber, 0.2-0.5 parts of anti-glass fiber exposure agent, and 0.5-1 parts of antioxidant.

[0013] The random copolymerized polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, the base material and modified glass fiber are fed into a twin-screw extruder, mixed and extruded, pelletized to obtain granules, and dried to obtain a glass fiber reinforced polypropylene composite material.

[0014] As a preferred embodiment, during the co-extrusion, the extrusion process parameters are: extrusion temperature 160° C. to 220° C., and rotation speed 300 rpm to 400 rpm.

[0015] As a preferred embodiment, during drying, the granular material is dried at 60° C. to 80° C. for 2 h to 4 h.

[0016] As a preferred embodiment, the feeding speed is 30kg / h to 50kg / h.

[0017] A third object of the present invention is to provide an application of the above-mentioned glass fiber reinforced polypropylene composite material in 3D printing, specifically using the glass fiber reinforced polypropylene composite material as a 3D printing material, and the printed parts after 3D printing have the characteristics of low warping and high strength.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a glass fiber reinforced polypropylene composite material. The present invention prepares the glass fiber reinforced polypropylene composite material by compounding random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, anti-glass fiber exposure agent and antioxidant. The low crystallinity of random copolymer polypropylene is used to reduce matrix shrinkage, and the calcium carbonate masterbatch and glass fiber form a rigid network to further limit shrinkage, and the anisotropy is reduced by synergistic dispersion. Random copolymer polypropylene with lower crystallinity is selected as the matrix, and its low shrinkage property provides an optimized basic environment for other additives. Glass fiber modification and anti-exposure agent jointly improve the fiber-matrix interface and reduce local warping caused by interfacial stress. Antioxidant maintains the processing consistency of the composite material and avoids shrinkage fluctuations caused by degradation. Calcium carbonate masterbatch and modified glass fiber synergistically form a rigid network, disperse shrinkage stress, and jointly improve dimensional stability. Anisotropic shrinkage is controlled by glass fiber orientation, but excessive amount should be avoided to cause decreased fluidity or interfacial stress concentration. Anti-exposure agent further optimizes its dispersibility. Antioxidants protect other components (such as the fiber coating) from thermal oxidation, ensuring long-term performance stability during processing, use, and storage of printed products. The synergistic interaction between the components of the glass fiber-reinforced polypropylene composite material ensures that large-scale 3D printed parts will not exhibit significant warping or cracking at room temperature.

[0020] The glass fiber reinforced polypropylene composite material prepared by the present invention can ensure that no obvious warping and cracking occurs during large-scale 3D printing, and has a small molding shrinkage rate. During long-term printing, there is no need for human beings to constantly observe the printing status, which frees up labor. It can also ensure good surface aesthetics and strength of the printed parts, making it widely applicable in the field of industrial production. Compared with materials such as polylactic acid and acrylonitrile-butadiene-styrene copolymer, the cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a DSC temperature rise curve of the glass fiber reinforced polypropylene composite material prepared in Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention.

[0022] Figure 2 Graph showing the warping degree of 3D printed parts made from the glass fiber reinforced polypropylene composite materials prepared in Example 1, Example 2, and Comparative Example 2 of the present invention.

[0023] Figure 3 This is an SEM image of the glass fiber reinforced polypropylene composite material prepared in Example 1 of the present invention.

[0024] Figure 4 This is an SEM image of the glass fiber reinforced polypropylene composite material prepared in Comparative Example 1 of the present invention.

[0025] Figure 5 Schematic diagram of a spline for detecting the warpage of a 3D printed part according to the present invention.

[0026] Figure 6 This is a screw extrusion 3D printer used in the present invention.

[0027] Description of reference numerals:

[0028] 1. Feed port, 2. Motor, 3. Heating coil, 4. Nozzle, 5. Printing platform. DETAILED DESCRIPTION

[0029] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention is further described below with reference to specific examples and accompanying drawings. However, the examples are not intended to limit the present invention. The following experimental and detection methods are conventional methods unless otherwise specified; the reagents and raw materials are commercially available unless otherwise specified.

[0030] Regarding the fact mentioned in the background technology of the present invention: during 3D printing, printed parts have warped and cracked. Conventional solutions include: first, improving the printing process and equipment. Stress concentration can be reduced by optimizing the printing path, but the operator needs to have strong structural design expertise and reserves, and the repeatability is weak; second, reducing the warping of the printed material by increasing the cabin temperature, reducing stress concentration and cracking, but large-scale 3D printing equipment modification is difficult and costly; third, when using the existing printing material polypropylene, printed parts are prone to warping, stress concentration, and cracking, which greatly limits its application in industrial production. Based on the above technical problems, the present invention provides a glass fiber reinforced polypropylene composite material and its preparation method and application.

[0031] The technical solution of the present invention is described in detail below.

[0032] The present invention first provides a glass fiber reinforced polypropylene composite material, which is composed of the following raw materials in parts by weight: 50-70 parts of random copolymer polypropylene, 10-30 parts of calcium carbonate masterbatch, 10-30 parts of modified glass fiber, 0.2-0.5 parts of glass fiber exposure prevention agent, and 0.5-1 parts of antioxidant.

[0033] For the components in the above-mentioned composite material, if the calcium carbonate masterbatch is less than 10 parts, a small amount of calcium carbonate masterbatch promotes crystallization, which will increase warpage. A high content of calcium carbonate masterbatch inhibits molecular chain activity, hinders crystallization, and thus reduces warpage. If the calcium carbonate masterbatch is too high, above 30 parts, it will cause stress concentration and mechanical properties to decline. The calcium carbonate masterbatch of the present invention is 10-20 parts, which can achieve better performance of the composite material. When the glass fiber is less than 10 parts, it is difficult to achieve the purpose of reducing the warpage of polypropylene printing, and the effect of improving the strength of the composite material is relatively weak. However, a glass fiber content of more than 30 parts will lead to an excessively high fiber content in the composite material, affecting the overall flow properties of the composite material, thereby increasing the difficulty of processing and printing the composite material particles. In addition, an excessively high fiber content will make the aggregation in the composite material more obvious, leading to stress concentration, which will have a negative impact on the mechanical strength of the material, and the surface quality of the printed model will be poor, and there may be fibers floating on the surface.

[0034] It should be noted that the preparation method of the modified glass fiber is as follows: according to the dosage ratio of 0.8g-1.2g:5mL, the glass fiber is immersed in a silane coupling agent ethanol solution with a mass concentration of 10% for 24 hours to obtain the modified glass fiber.

[0035] Regarding the modification of the aforementioned glass fibers, using a silane coupling agent to modify the glass fibers can enhance the interfacial bonding strength and compatibility between the glass fibers and other raw materials in the composite material. Silane coupling agents are bifunctional compounds: one end can chemically react with the hydroxyl groups (-OH) on the glass fiber surface to form a covalent bond; the other end can physically or chemically interact with the polymer chains in the polypropylene matrix. Through this dual action, the silane coupling agent forms a "bridge" between the glass fiber and the polypropylene matrix, significantly improving the interfacial bonding strength. However, the high interfacial tension between unmodified glass fibers and the polypropylene matrix results in poor compatibility and the formation of defects at the interface. By forming a thin modified layer at the interface, the silane coupling agent reduces the interfacial tension and improves the compatibility between the two.

[0036] It should be noted that the random copolymer polypropylene contains 3% to 7% by mass of ethylene, and the random copolymer polypropylene is in the form of spherical particles of 2mm to 3mm. Adding 3% to 7% by mass of ethylene to polypropylene can reduce the crystallinity of polypropylene, thereby reducing printing warping, and can improve the toughness of polypropylene to prevent the model from cracking during printing or use. When the ethylene content is too low, it is similar to traditional isotactic polypropylene and cannot achieve the purpose of reducing the crystallinity of polypropylene. When the ethylene content is too high, although the crystallinity will decrease, the strength and modulus of the composite material will decrease, making it difficult to meet the strength requirements for practical applications and the application value is low.

[0037] It should be noted that the content of calcium carbonate in the calcium carbonate master batch is 95% to 98%, and the particle size of the calcium carbonate master batch is 2mm to 3mm. The higher the content of calcium carbonate in the master batch, the lower the content of additives. The additives contain lubricants, aluminate coupling agents and titanate coupling agents. Too high content of additives will reduce the strength of the composite material. In the present application, the content of calcium carbonate in the calcium carbonate master batch is 95% to 98%, i.e. the content of additives is relatively low, so it will not affect the strength performance of the composite material.

[0038] In the present application, when the glass fiber is modified by using a silane coupling agent, the silane coupling agent used is vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, isobutyltriethoxysilane or isocyanate silane coupling agent.

[0039] The above-mentioned method for preparing the glass fiber reinforced polypropylene composite material comprises the following steps:

[0040] The following raw materials are weighed: 50 to 70 parts of random copolymerized polypropylene, 5 to 20 parts of calcium carbonate master batch, 10 to 30 parts of modified glass fiber, 0.2 to 0.5 parts of anti-glass fiber exposure agent, and 0.5 to 1 part of antioxidant;

[0041] The polypropylene, calcium carbonate master batch, anti-glass fiber exposure agent and antioxidant are mixed uniformly to obtain a base material. The base material is fed into a twin-screw extruder at a speed of 30kg / h to 50kg / h for processing. The glass fiber is fed into the plasticizing zone of the twin-screw extruder and is blended and extruded with the base material at a screw rotation speed of 300rpm to 400rpm and a temperature of 160℃ to 220℃. After water cooling and air cooling, the material is cut into granules. The granules are dried at a temperature of 60℃ to 80℃ for 2h to 4h to obtain the glass fiber reinforced polypropylene composite material.

[0042] It should be noted that the laboratory twin-screw extrusion equipment is used in the present application, which has nine heating zones. The temperatures of the first to ninth zones are 160℃-180℃-190℃-200℃-205℃-210℃-215℃-215℃-220℃, respectively. After feeding, the temperature starts to increase from 160℃, and after passing through the above-mentioned nine heating temperature zones, it reaches the extrusion outlet, and the temperature of the extrusion outlet is 220℃.

[0043] The glass fiber reinforced polypropylene composite material prepared above is used in 3D printing. Specifically, the glass fiber reinforced polypropylene composite material is used as a 3D printing material. The printed part after 3D printing has the characteristics of low warping and high strength.

[0044] The technical effects of the present application will be described below in conjunction with specific examples and comparative examples.

[0045] Example 1

[0046] A glass fiber reinforced polypropylene composite material, characterized in that it is composed of the following raw materials in parts by weight: random copolymerized polypropylene with a particle size of 2-3 mm 65 parts (containing 5% ethylene by mass percentage), calcium carbonate masterbatch with a particle size of 2-3 mm 10 parts (calcium carbonate content 96.5%), modified glass fiber 25 parts, anti-glass fiber exposure agent (modified ethylene bis fatty acid amide) 0.3 parts, antioxidant 0.8 parts (antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester) 0.4 parts and antioxidant 168 (tris[2.4-di-tert-butylphenyl]phosphite) 0.4 parts).

[0047] The preparation method of the modified glass fiber is as follows: according to the usage ratio of 1 g:5 mL, the glass fiber is soaked in an ethanol solution of vinyl triethoxysilane with a mass concentration of 10% for 24 h to obtain the modified glass fiber.

[0048] The preparation method of the above-mentioned glass fiber reinforced polypropylene composite material comprises the following steps:

[0049] The random copolymerized polypropylene, calcium carbonate masterbatch, modified glass fiber, anti-glass fiber exposure agent and antioxidant are weighed according to the weight parts of each raw material.

[0050] The polypropylene, calcium carbonate masterbatch, anti-glass fiber exposure agent and antioxidant are uniformly mixed to obtain a base material, which is fed into a twin-screw extruder at a speed of 30 kg / h for processing, the modified glass fiber is fed into the plasticizing zone of the twin-screw extruder, and the base material is blended and extruded at a screw speed of 300 rpm through one to nine segments, starting from 160°C, and passing through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C at 220°C, and then cooled by water and air, cut into particles, dried at 80°C for 3 h to obtain a glass fiber reinforced polypropylene composite material, denoted as PP-GF, and the SEM image is shown in Figure 3 .

[0051] Example 2

[0052] A glass fiber reinforced polypropylene composite material, characterized in that it is composed of the following raw materials in parts by weight: random copolymerized polypropylene with a particle size of 2-3 mm 65 parts (containing 5% ethylene by mass percentage), calcium carbonate masterbatch with a particle size of 2-3 mm 10 parts (calcium carbonate content 96.5%), modified glass fiber 25 parts, anti-glass fiber exposure agent (modified ethylene bis fatty acid amide) 0.3 parts, antioxidant 0.8 parts (antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester) 0.4 parts and antioxidant 168 (tris[2.4-di-tert-butylphenyl]phosphite) 0.4 parts).

[0053] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of vinyltrimethoxysilane with a mass concentration of 10% for 24 hours at a dosage ratio of 1 g:5 mL to obtain the modified glass fiber.

[0054] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0055] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0056] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 50 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 400 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, and pelletized to obtain pellets, which are dried at 80°C for 2 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0057] Example 3

[0058] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 70 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 7% by mass of ethylene), 10 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 30 parts of modified glass fiber, 0.5 part of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 1 part of an antioxidant (antioxidant 1010 (0.5 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and antioxidant 168 (0.5 part of tris[2,4-di-tert-butylphenyl] phosphite).

[0059] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of vinyl tris(β-methoxyethoxy)silane with a mass concentration of 10% for 24 hours at a dosage ratio of 0.8 g:5 mL to obtain the modified glass fiber.

[0060] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0061] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0062] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 40 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 350 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, and pelletized to obtain pellets, which are dried at 80°C for 4 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0063] Example 4

[0064] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 55 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 7% by mass of ethylene), 15 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 20 parts of modified glass fiber, 0.3 part of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 0.6 part of an antioxidant (0.3 part of antioxidant 1010 (0.3 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and 0.3 part of antioxidant 168 (0.3 part of tris[2,4-di-tert-butylphenyl] phosphite).

[0065] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of isobutyltriethoxysilane with a mass concentration of 10% for 24 hours at a dosage ratio of 1.2 g:5 mL to obtain the modified glass fiber.

[0066] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0067] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0068] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 45 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 400 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, pelletized to obtain pellets, and dried at 80°C for 2 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0069] Example 5

[0070] A glass fiber reinforced polypropylene composite material, characterized in that it is composed of the following raw materials in parts by weight: 60 parts of random copolymerized polypropylene with a particle size of 2-3 mm (containing 6% ethylene by mass percentage), 10 parts of calcium carbonate masterbatch with a particle size of 2-3 mm (containing 96.5% calcium carbonate), 15 parts of modified glass fiber, 0.5 parts of anti-glass fiber exposure agent (modified ethylene bis fatty acid amide), and 0.5 parts of antioxidant (0.25 parts of antioxidant 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester) and 0.25 parts of antioxidant 168 (tris[2.4-di-tert-butylphenyl]phosphite)).

[0071] The preparation method of the modified glass fiber is as follows: according to the usage ratio of 1 g:5 mL, the glass fiber is soaked in an ethanol solution of isocyanate silane coupling agent with a mass concentration of 10% for 24 h to obtain the modified glass fiber.

[0072] The preparation method of the above-mentioned glass fiber reinforced polypropylene composite material comprises the following steps:

[0073] The random copolymerized polypropylene, calcium carbonate masterbatch, modified glass fiber, anti-glass fiber exposure agent, and antioxidant are weighed according to the weight parts of each raw material.

[0074] The polypropylene, calcium carbonate masterbatch, anti-glass fiber exposure agent, and antioxidant are uniformly mixed to obtain a base material, which is fed into a twin-screw extruder at a speed of 30 kg / h for processing. The modified glass fiber is fed into the plasticizing zone of the twin-screw extruder and blended with the base material at a screw speed of 300 rpm through one to nine segments, starting from 160°C, and heated at 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and then extruded at 220°C. After water cooling and air cooling, the material is cut into granules, dried at 80°C for 4 h, and then a glass fiber reinforced polypropylene composite material is obtained, which is denoted as PP-GF.

[0075] Example 6

[0076] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 65 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 5% by mass of ethylene), 10 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 30 parts of modified glass fiber, 0.2 parts of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 1 part of an antioxidant (antioxidant 1010 (0.5 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and antioxidant 168 (0.5 parts of tris[2,4-di-tert-butylphenyl] phosphite).

[0077] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of vinyltriethoxysilane with a mass concentration of 10% for 24 hours at a dosage ratio of 1 g:5 mL to obtain the modified glass fiber.

[0078] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0079] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0080] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 40 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 300 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, pelletized to obtain pellets, and dried at 80°C for 3 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0081] Example 7

[0082] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 55 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 4% by mass of ethylene), 20 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 10 parts of modified glass fiber, 0.4 parts of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 0.5 parts of an antioxidant (0.25 parts of antioxidant 1010 (0.25 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and 0.25 parts of antioxidant 168 (0.25 parts of tris[2,4-di-tert-butylphenyl] phosphite).

[0083] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of isobutyltriethoxysilane with a mass concentration of 10% for 24 hours at a dosage ratio of 0.8 g:5 mL to obtain the modified glass fiber.

[0084] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0085] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0086] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 50 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 400 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, and pelletized to obtain pellets, which are dried at 80°C for 3 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0087] Example 8

[0088] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 70 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 5% by mass of ethylene), 15 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 25 parts of modified glass fiber, 0.3 part of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 0.8 part of an antioxidant (0.4 part of antioxidant 1010 (0.4 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate)) and 0.4 part of antioxidant 168 (0.4 part of tris[2,4-di-tert-butylphenyl] phosphite).

[0089] The modified glass fiber is prepared by soaking the glass fiber in an ethanol solution of vinyl tris(β-methoxyethoxy)silane with a mass concentration of 10% for 24 hours at a dosage ratio of 1 g:5 mL to obtain the modified glass fiber.

[0090] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0091] Random copolymer polypropylene, calcium carbonate masterbatch, modified glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0092] Polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, and the base material is fed into a twin-screw extruder at a speed of 30 kg / h for processing. The modified glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 300 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. The mixture is water-cooled and air-cooled, and pelletized to obtain pellets, which are dried at 80°C for 3 hours to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-GF.

[0093] In order to further illustrate the technical effects of the present invention, the present invention is also provided with comparative examples, as follows:

[0094] Comparative Example 1

[0095] Compared with Example 1, the difference is that the glass fiber is not modified.

[0096] A glass fiber reinforced polypropylene composite material is characterized in that it is composed of the following raw materials in parts by weight: 65 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 5% by mass of ethylene), 10 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 25 parts of glass fiber, 0.3 part of a glass fiber exposure prevention agent (modified ethylene bis fatty acid amide), 0.8 part of an antioxidant (antioxidant 1010 (0.4 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and antioxidant 168 (0.4 part of tris[2,4-di-tert-butylphenyl] phosphite).

[0097] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0098] Random copolymer polypropylene, calcium carbonate masterbatch, glass fiber, glass fiber exposure prevention agent and antioxidant are weighed according to the weight proportions of the above raw materials.

[0099] Polypropylene, calcium carbonate masterbatch, anti-glass fiber exposure agent and antioxidant are mixed to obtain a base material, and the base material is fed to a twin-screw extruder at a speed of 30 kg / h for processing. The glass fiber side feed is fed into the plasticizing zone of the twin-screw extruder and heated with the base material at a screw speed of 300 rpm through sections one to nine, starting from 160°C, through 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and blended and extruded at 220°C. After water cooling and air cooling, pelletizing is performed to obtain pellets, which are dried at 65°C for 3 h to obtain a glass fiber reinforced polypropylene composite material, recorded as PP-NGF, and its SEM picture is shown as follows Figure 4 shown.

[0100] Comparative Example 2

[0101] Compared with Example 1, the difference is that no modified glass fiber is added.

[0102] A composite material based on polypropylene, characterized in that it is composed of the following raw materials in parts by weight: 65 parts of random copolymer polypropylene with a particle size of 2 mm to 3 mm (containing 5% by mass of ethylene), 10 parts of calcium carbonate masterbatch with a particle size of 2 mm to 3 mm (calcium carbonate content of 96.5%), 0.8 parts of antioxidants (antioxidant 1010 (0.4 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and antioxidant 168 (0.4 parts of tris[2,4-di-tert-butylphenyl]phosphite).

[0103] The preparation method of the glass fiber reinforced polypropylene composite material comprises the following steps:

[0104] Weigh random copolymer polypropylene, calcium carbonate masterbatch and antioxidant according to the weight proportions of the above raw materials.

[0105] Polypropylene, calcium carbonate masterbatch and antioxidant are mixed to obtain a base material, and the base material is fed to a twin-screw extruder at a speed of 30 kg / h for processing. The base material is heated from 160°C at a screw speed of 300 rpm through sections one to nine, and is subjected to temperatures of 160°C-180°C-190°C-200°C-205°C-210°C-215°C-215°C-220°C, and is blended and extruded at 220°C. The base material is water-cooled and air-cooled, and is pelletized to obtain pellets. The pellets are dried at 65°C for 3 hours to obtain a composite material based on polypropylene, which is recorded as PP.

[0106] The properties of the glass fiber reinforced polypropylene composite materials prepared in Examples 1 to 8 and Comparative Example 1 of the present invention and the polypropylene-based composite materials prepared in Comparative Example 2 were tested, and each composite material was used to prepare 3D printed parts. Figure 6 The screw extrusion 3D printer shown is used for printing, and the specific process is as follows: the printer structure is an open frame, and printing is performed at room temperature. During the printing process, the PP-GF particles prepared in Examples 1 to 8, the PP-NGF particles in Example 1, and the PP particles prepared in Example 2 are respectively added into the printer through the feed port 1, and then passed through the heating coil 3, through the four temperature sections of 140°C-165°C-180°C-200°C, the granular materials prepared in each example and comparative example are moved to the nozzle 4 position, and printed through the nozzle 4. The material of the printing platform 5 is glass, the diameter of the nozzle 4 is 2 mm, the layer height is 0.4 mm, the extrusion flow rate is 100%, the printing speed is 100 mm / s, and the performance test is performed after printing is completed. The results are shown in Table 1 below.

[0107] The warpage of 3D printed parts is calculated using the following formula: w = (h1-h2) / h2*100%, where h1 is the end warping height and h2 is the spline thickness. The schematic diagram of the spline is shown in Figure 5 shown.

[0108] Table 1 Performance test table of glass fiber reinforced polypropylene composite material of the present invention

[0109]

[0110]

[0111] As shown in Table 1, the glass fiber reinforced polypropylene composite material prepared by the present invention has light weight and low density, about 1.20 g / cm 3 The glass fiber reinforced polypropylene composite material prepared in the embodiment of the present invention has the advantages of low crystallinity (<15%), not easy to warp, not easy to absorb moisture and recyclable. The crystallinity of the glass fiber reinforced polypropylene composite material prepared in the embodiment of the present invention is 10% to 15%, the crystallization rate is low, and the Figure 1 and Figure 2 It can be seen that the peak width is the width range value from the crystallization starting temperature to the end temperature detected by differential scanning calorimetry. The wider the melting peak, the greater the molecular weight dispersion of the glass fiber reinforced polypropylene composite material, the more irregular the molecular chain, and the less likely it is to crystallize, which is reflected in the low warpage characteristic of the material. The peak widths of Examples 1 to 3 are all >15°C, so the warpage is relatively low. However, compared to the examples, the peak widths of Comparative Examples 1 and 2 are smaller. The crystallinity of the two materials reaches 35% and 40%, respectively, so the warpage is relatively high.

[0112] In summary, the glass fiber reinforced polypropylene composite material prepared by the present invention can ensure that there is no obvious warping and cracking during the large-scale 3D printing process, and has a small molding shrinkage rate, and can ensure good surface aesthetics and strength of the printed parts, so that it can be widely used in the field of industrial production.

[0113] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A glass fiber reinforced polypropylene composite material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 50-70 parts of random copolymer polypropylene, 10-30 parts of calcium carbonate masterbatch, 10-30 parts of modified glass fiber, 0.2-0.5 parts of anti-glass fiber exposure agent and 0.5-1 parts of antioxidant.

2. The glass fiber reinforced polypropylene composite material according to claim 1, characterized in that: The modified glass fiber is prepared by soaking the glass fiber in a silane coupling agent ethanol solution with a mass concentration of 10% for 24 hours at a dosage ratio of 0.8 g to 1.2 g:5 mL to obtain the modified glass fiber.

3. The glass fiber reinforced polypropylene composite material according to claim 1, characterized in that: The random copolymer polypropylene contains 3% to 7% by mass of ethylene, and the random copolymer polypropylene is in the form of spherical particles with a diameter of 2mm to 3mm.

4. The glass fiber reinforced polypropylene composite material according to claim 1, characterized in that: The calcium carbonate content in the calcium carbonate masterbatch is 95% to 98%, and the particle size of the calcium carbonate masterbatch is 2mm to 3mm.

5. The glass fiber reinforced polypropylene composite material according to claim 2, characterized in that: The silane coupling agent is vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, isobutyltriethoxysilane or isocyanate silane coupling agent.

6. A method for preparing the glass fiber reinforced polypropylene composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Weigh the following raw materials in parts by weight: 50-70 parts of random copolymer polypropylene, 10-30 parts of calcium carbonate masterbatch, 10-30 parts of modified glass fiber, 0.2-0.5 parts of anti-glass fiber exposure agent, and 0.5-1 parts of antioxidant; The random copolymerized polypropylene, calcium carbonate masterbatch, glass fiber exposure prevention agent and antioxidant are mixed to obtain a base material, the base material and modified glass fiber are fed into a twin-screw extruder, mixed and extruded, pelletized to obtain granules, and dried to obtain a glass fiber reinforced polypropylene composite material.

7. The preparation method according to claim 6, characterized in that During the blending extrusion, the extrusion process parameters are: extrusion temperature 160° C. to 220° C., and rotation speed 300 rpm to 400 rpm.

8. The preparation method according to claim 6, characterized in that During drying, the granular material is dried at 60° C. to 80° C. for 2 h to 4 h.

9. The preparation method according to claim 6, characterized in that The feeding speed is 30kg / h to 50kg / h.

10. Use of the glass fiber reinforced polypropylene composite material according to any one of claims 1 to 5 in 3D printing.

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