PET (Polyethylene Terephthalate) composite material as well as preparation method and application thereof

Abstract

The invention discloses a PET composite material as well as a preparation method and application thereof, and belongs to the technical field of polymer engineering plastics. The PET composite material provided by the invention is prepared from the following components in parts by mass: 38 to 82 parts of first PET resin, 8 to 42 parts of carbon fibers, 0.5 to 6.5 parts of a toughening agent and 0.05 to 1.1 parts of a nucleating agent, on the basis of the mass of the carbon fiber, the surface of the carbon fiber contains 1-4% by mass of second PET resin; the nucleating agent comprises long-chain saturated linear carboxylate, and the number of carbon atoms in the long-chain saturated linear carboxylate is 22 to 28. The PET composite material provided by the invention has high modulus and also has excellent thermal stability and toughness. Meanwhile, the preparation method of the PET composite material provided by the invention is simple, and practical application is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of polymer engineering plastics technology, and particularly relates to a PET composite material, its preparation method and application. Background Technology

[0002] Carbon fiber reinforced PET materials possess ultra-high modulus and are widely used in automotive, military, and other fields for projects requiring plastic-to-steel replacement and lightweighting. However, carbon fiber reinforced PET suffers from poor toughness, and because PET itself is a highly crystalline resin, incomplete crystallization is prone to occur, leading to a significant decrease in the material's mechanical and thermal stability. Therefore, how to provide a material that can maintain the high modulus properties of carbon fiber reinforced PET while improving the mechanical and thermal stability of the composite material has become a research hotspot. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a PET composite material that can maintain high modulus while also having excellent toughness and thermal stability, as well as its preparation method and application.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a PET composite material comprising the following components in parts by weight:

[0005] The first component consists of 38-82 parts PET resin, 8-42 parts carbon fiber, 0.5-6.5 parts toughening agent, and 0.05-1.1 parts nucleating agent.

[0006] The carbon fiber surface contains 1-4% by mass of a second PET resin, based on the mass of the carbon fiber.

[0007] The nucleating agent comprises a long-chain saturated linear carboxylate, wherein the long-chain saturated linear carboxylate has 22-28 carbon atoms.

[0008] The present invention provides a PET composite material by introducing carbon fibers with a surface containing a second PET resin of a specific mass percentage range, and simultaneously introducing long-chain saturated linear carboxylates as nucleating agents; the two can synergistically improve the overall performance of the PET composite material.

[0009] Specifically, by selecting a second PET resin with a specific mass percentage range for surface coating, it exhibits good compatibility with the first PET resin and effectively improves the crystallinity of the first PET resin surrounding the carbon fibers, resulting in PET composite materials with better toughness and thermal stability. The addition of long-chain saturated linear carboxylates with 22-28 carbon atoms as nucleating agents further enhances the crystallinity of the first PET resin in other regions, maintaining the high modulus of the PET composite while improving the product's thermal stability and toughness.

[0010] The content of the second PET resin can be determined by TGA. The mass loss is the mass lost when the temperature is raised from 30°C to 350-750°C under a nitrogen atmosphere.

[0011] The type of resin included on the carbon fiber can be determined by X-ray photoelectron spectroscopy (XPS).

[0012] For example, in the PET composite material, the first PET resin can be any point value or any two-point range value between 38 and 82 parts, such as 40-80 parts, or 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 82 parts, etc.; the carbon fiber can be any point value or any two-point range value between 8 and 42 parts, such as 10-40 parts, or 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, etc.; the toughening agent can be between 0.5 and 6.5 parts. The amount of nucleating agent can be any point value or any range of two points, for example, it can be 1-6 parts, or it can be 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 5.5 parts, 6.0 parts, 6.5 parts, etc.; the amount of nucleating agent can be any point value or any range of two points between 0.05-1.1 parts, for example, it can be 0. 1-1 portion, or can be 0.05 portions, 0.1 portions, 0.15 portions, 0.2 portions, 0.25 portions, 0.3 portions, 0.35 portions, 0.4 portions, 0.45 portions, 0.5 portions, 0.55 portions, 0.6 portions, 0.65 portions, 0.7 portions, 0.75 portions, 0.8 portions, 0.85 portions, 0.9 portions, 0.95 portions, 1.0 portion, 1.05 portions, 1.1 portions, etc.

[0013] For example, the mass percentage of the second PET resin, based on the mass of carbon fiber, can be any point value or any two-point range value between 1 and 4%, such as 2.4-3.6%, or 1%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.4%, 3.6%, 4%, etc.

[0014] For example, the number of carbon atoms in the long-chain saturated linear carboxylate can be any point value or any two-point range value between 22 and 28, such as 22, 23, 24, 25, 26, 27, and 28.

[0015] Preferably, in the PET composite material, the mass percentage of the first PET resin is 40% or more.

[0016] As a preferred embodiment of the PET composite material of the present invention, the PET composite material comprises the following components in parts by weight: 60-70 parts of first PET resin, 20-30 parts of carbon fiber, 2-4 parts of toughening agent, and 0.2-0.6 parts of nucleating agent.

[0017] This invention has found that the mass fraction of components in PET composite materials affects the overall performance of the product. When the mass fraction of components is further selected within the above-mentioned range, the resulting product has a higher modulus, better thermal stability, and better toughness.

[0018] As a preferred embodiment of the PET composite material of the present invention, the surface of the carbon fiber contains 2.2-3.8% by mass of a second PET resin, based on the mass of the carbon fiber.

[0019] The present invention has found that the mass percentage of the second PET resin included on the carbon fiber affects the compatibility between the carbon fiber and the first PET resin, and in turn affects the crystallinity of the first PET resin. When the mass percentage of the second PET resin is further selected to be 2.2-3.8%, the overall performance of the obtained product is better.

[0020] It should be noted that the introduction of the second PET resin onto the carbon fiber surface can be done using any conventional method. Furthermore, this invention places no restrictions on the precursor fibers used before sizing the carbon fibers, such as on their diameter or length.

[0021] For example, the second PET resin on the carbon fiber surface is introduced by mixing it with a surfactant and a diluent to form a sizing agent. This invention does not limit the method of sizing the carbon fiber; for example, impregnation or ultrasonic methods can be used.

[0022] This invention does not impose any particular limitations on the selection of surfactants and diluents used in the introduction of sizing agents; any surfactants and diluents applicable to the field of sizing agents can achieve the objectives of this invention. Exemplarily, the surfactant includes at least one of nonylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, octylphenol polyoxyethylene ether, and triphenylethylphenol polyoxyethylene polyoxypropylene ether; the diluent includes at least one of acetone, cyclopentanone, and anhydrous ethanol. As a preferred embodiment of the PET composite material of this invention, the nucleating agent further includes ultrafine talc powder.

[0023] Preferably, in the nucleating agent, the mass ratio of long-chain saturated linear carboxylate to ultrafine talc is (1-3):1.

[0024] For example, the mass ratio of long-chain saturated linear carboxylate to ultrafine talc can be any point value or any two points between (1-3):1, such as 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc.

[0025] This invention has found that when ultrafine talc powder is further introduced into the nucleating agent, it can provide more crystallization sites for the PET composite material, thereby further improving the crystallization performance of the first PET resin and thus enhancing the overall effect of the product.

[0026] It should be noted that the present invention does not have any special requirements on the mesh size of the ultrafine talc powder; the purpose of the present invention can be achieved as long as the mesh size of the ultrafine talc powder is within the specified range. For example, the mesh size of the ultrafine talc powder can be 10,000 to 40,000 mesh, such as 10,000 mesh, 20,000 mesh, 30,000 mesh, 40,000 mesh, etc.

[0027] In a preferred embodiment of the PET composite material of the present invention, the intrinsic viscosity of the first PET resin and the second PET resin are each independently 0.56-0.92 dL / g. The present invention does not have specific requirements for the intrinsic viscosity of the first PET resin and the second PET resin; optimal results can be achieved within the intrinsic viscosity range of 0.56-0.92 dL / g given in the present invention. Furthermore, the first PET resin and the second PET resin can be the same or different in the present invention.

[0028] For example, the intrinsic viscosity of the first PET resin and the second PET resin can be any point value or any two points between 0.56 and 0.92 dL / g, such as 0.56 dL / g, 0.60 dL / g, 0.61 dL / g, 0.62 dL / g, 0.63 dL / g, 0.64 dL / g, 0.65 dL / g, 0.66 dL / g, 0.67 dL / g, 0.68 dL / g, 0.70 dL / g, 0.72 dL / g, 0.74 dL / g, 0.76 dL / g, 0.78 dL / g, 0.80 dL / g, 0.82 dL / g, 0.84 dL / g, 0.86 dL / g, 0.88 dL / g, 0.92 dL / g, etc.

[0029] Preferably, the intrinsic viscosity of the first PET resin is 0.58-0.68 dL / g.

[0030] Preferably, the intrinsic viscosity of the second PET resin is 0.70-0.90 dL / g.

[0031] The intrinsic viscosity of the first PET resin and the second PET resin of the present invention is obtained by testing according to GB / T14190-2017.

[0032] In a preferred embodiment of the PET composite material of the present invention, the toughening agent includes at least one of ethylene-based terpolymers, ethylene-octene elastomers, and ethylene-butene elastomers.

[0033] Preferably, the toughening agent has a melt flow index of 10-20 g / 10 min at 190°C and 2.16 kg. The test method is in accordance with ISO 1133-1:2011.

[0034] The present invention does not impose a specific limitation on the melt index of the toughening agent; the effects of the present invention can be achieved within the range of 10-20 g / 10 min given in the present invention.

[0035] Preferably, the toughening agent is an ethylene-based terpolymer.

[0036] More preferably, the ethylene-based terpolymer is an ethylene-propylene-1-octene terpolymer.

[0037] In a preferred embodiment of the PET composite material of the present invention, the long-chain saturated linear carboxylate includes at least one of calcium octadecanoate and sodium docosanoate.

[0038] In a preferred embodiment of the PET composite material of the present invention, the PET composite material further includes 0.1-5 parts of processing aids.

[0039] Preferably, the processing aids include antioxidants and lubricants.

[0040] Preferably, the antioxidant includes a first antioxidant and a second antioxidant;

[0041] For example, the first antioxidant includes hindered phenolic antioxidants, and the second antioxidant includes pentaerythritol tetra(3-lauryl thiopropionate) antioxidants.

[0042] For example, the lubricant includes pentaerythritol stearate.

[0043] In a second aspect of the present invention, the present invention provides a method for preparing the PET composite material, the method comprising the following steps: weighing and mixing the dried raw materials and feeding them into a twin-screw extruder, and extruding, stretching, cooling, pelletizing and drying to obtain the PET composite material.

[0044] In a preferred embodiment of the preparation method described in this invention, the feed rate of the twin-screw extruder is 300-450 kg / hour; the screw temperatures of each section of the twin-screw extruder from the feed port to the die head are 110-130℃, 230-250℃, 250-270℃, 250-270℃, 240-260℃, 230-250℃, 230-250℃, 250-270℃, 260-280℃, and 260-280℃, respectively; and the screw speed is 300-400 rpm.

[0045] In a third aspect, the present invention provides the application of the PET composite material in the preparation of automotive interior structures and weapon rack materials.

[0046] For example, the PET composite material is used in the preparation of materials for seats, armrests, and dashboard systems in automobile interior structures, or in the preparation of interior structural components in armored vehicles, or in the preparation of materials for missile racks.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This invention provides a PET composite material in which carbon fibers containing a specific mass percentage range of a second PET resin on their surface are introduced, along with a long-chain saturated linear carboxylate as a nucleating agent. These two components synergistically enhance the overall performance of the PET composite material. Specifically, the resulting PET composite material exhibits a flexural modulus exceeding 19770 MPa, a heat distortion temperature exceeding 220°C, and a notched impact strength of 8.5 KJ / m². 2 Furthermore, the preparation method of the PET composite material provided by this invention is simple to operate and beneficial to actual production. Detailed Implementation

[0049] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0050] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in the field.

[0051] PET-1: PET FG600, intrinsic viscosity 0.68 dl / g, Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0052] PET-2: CR-8828, intrinsic viscosity 0.88 dl / g, Zhuhai Huarun Company;

[0053] PET-3: CR-7702, intrinsic viscosity 0.58 dL / g, Zhuhai Huarun Company;

[0054] PET-4: EP901, intrinsic viscosity 0.9 dL / g, Yizheng Branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0055] Carbon fiber 1: Surface PET-2 mass percentage is 2.4%, self-made;

[0056] Carbon fiber 2: Surface PET-2 mass percentage is 1.6%, self-made;

[0057] Carbon fiber 3: Surface PET-2 mass percentage is 3.6%, self-made;

[0058] Carbon fiber 4: Surface PET-2 mass percentage is 1.2%, self-made;

[0059] Carbon fiber 5: Surface PET-1 mass percentage is 2.4%, self-made;

[0060] Carbon fiber 6: Surface PET-4 mass percentage is 2.4%, self-made;

[0061] Carbon fiber 7: The surface PU resin has a mass percentage of 2.4%, and it is self-made;

[0062] Carbon fiber 8: Surface PET-2 mass percentage is 5.2%, self-made;

[0063] Carbon fiber 9: Surface PET-2 mass percentage is 0.16%, self-made;

[0064] Toughening agent 1: Ethylene terpolymer, melt index 12 g / 10 min (tested at 190℃ and 2.16 kg); Elvaloy resins PTW, DuPont;

[0065] Toughening agent 2: Ethylene-octene elastomer, melt index 13 g / 10 min (190℃, 2.16 kg test), POE8137, Dow Chemical;

[0066] Nucleating agent 1: Calcium octadecanoate, LICOMONT CAV102 PWD, Clariant Chemicals;

[0067] Nucleating agent 2: Sodium docosanoate, commercially available;

[0068] Nucleating agent 3: a mixture of calcium octacosanate and ultrafine talc in a mass ratio of 2:1, wherein the calcium octacosanate is LICOMONT CAV102 PWD and the ultrafine talc is HTPULTRA5L (Imifa ratio).

[0069] Nucleating agent 4: Sodium stearate, commercially available;

[0070] Nucleating agent 5: Sodium beeswaxate, commercially available;

[0071] Nucleating agent 6: Sodium docosapentaenoic acid, commercially available;

[0072] Nucleating agent 7: Ultrafine talc, HTPULTRA 5L, Imifat ratio;

[0073] Antioxidant: A mixture of octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetrakis(3-lauryl thiopropionate) in a 1:1 mass ratio, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetrakis(3-lauryl thiopropionate) are commercially available;

[0074] Lubricant: Pentaerythritol stearate, commercially available;

[0075] The antioxidants and lubricants used in the parallel experiments of the examples and comparative examples were consistent;

[0076] The carbon fiber preparation method used in the embodiments and comparative examples can be any introduction method in the art. The present invention uses a sizing method. The sizing method used in the embodiments and comparative examples of the present invention is consistent, specifically: the carbon fiber precursor is fully immersed in the sizing agent, then the excess sizing agent is removed and then dried to obtain the corresponding carbon fiber; wherein, the immersion time is 0.5h and the temperature is 40℃, and the drying time is 4h and the temperature is 180℃.

[0077] Except for the difference in resin type, the surfactant and diluent used in the sizing agent are kept the same. The surfactant is nonylphenol polyoxyethylene ether, and the diluent is anhydrous ethanol. The difference in the mass percentage of the second PET resin based on carbon fiber can be achieved by adjusting the mass percentage of the second PET resin in the sizing agent, and the difference in the resin type on the carbon fiber surface can be achieved by adjusting the resin type in the sizing agent. In addition, the carbon fiber precursor used in the embodiments and comparative examples of this invention is consistent with that of SYT45 from Zhongfu Shenying Company.

[0078] Examples 1-14 and Comparative Examples 1-11

[0079] The present invention provides a PET composite material in the embodiments and comparative examples, the components (parts by mass) of the PET composite material are shown in Tables 1-2;

[0080] Table 1

[0081]

[0082]

[0083] Table 2

[0084]

[0085] The preparation method of the PET composite material provided in Example 1 includes the following steps:

[0086] After drying, the raw materials are weighed and mixed, then fed into a twin-screw extruder. The mixture undergoes extrusion, stranding, cooling, pelletizing, and drying to obtain a PET composite material. The twin-screw extruder has a feed rate of 400 kg / hour. The screw temperatures from the feed inlet to the die head are 120℃, 240℃, 260℃, 260℃, 250℃, 240℃, 240℃, 260℃, 270℃, and 270℃, respectively, and the screw speed is 350 rpm.

[0087] The preparation methods of the PET composite materials provided in Examples 2-14 and Comparative Examples 1-11 are consistent with those in Example 1, except that the relevant components are not required.

[0088] Example of effect

[0089] The effects of this invention are explored in the examples and comparative examples to investigate the properties of the PET composite materials prepared in the embodiments and comparative examples, specifically including the following aspects:

[0090] 1. Flexural modulus: Tested according to ISO 178-2019 at room temperature;

[0091] 2. Heat distortion temperature: Tested according to ISO 75-2:2004, with a test pressure of 1.82 MPa;

[0092] 3. Notched impact strength of simply supported beams: Tested according to ISO 179-1:2010 at room temperature;

[0093] The results of the above performance tests are recorded in Table 3;

[0094] Table 3

[0095]

[0096] As can be seen from Table 3, when the preparation method provided by this invention is used, the obtained PET composite material has excellent thermal stability and toughness, and also has a good modulus; specifically, the obtained product has a flexural modulus above 19770 MPa, a heat distortion temperature above 220℃, and a notched impact strength of 8.5 KJ / m². 2 above;

[0097] As can be seen from Examples 1-3, Comparative Examples 2 and 4, the mass fraction of the components affects the overall performance of the product. When the nucleating agent in Comparative Example 2 is too large, the notched impact strength of the simply supported beam of the product shows a significant downward trend. When the carbon fiber in Comparative Example 4 is too large, the notched impact strength of the simply supported beam of the product also shows a significant downward trend.

[0098] As can be seen from Example 1 and Comparative Example 1, the overall performance of the products is significantly reduced when no nucleating agent is added. As can be seen from Example 1 and Comparative Examples 8-11, when the nucleating agent is not the long-chain saturated linear carboxylate selected in this invention, the flexural modulus, heat distortion temperature, and notched impact strength of the simply supported beam of the products are significantly reduced. As can be seen from Example 1 and Example 14, when ultrafine talc powder is further added to the nucleating agent, the overall performance of the products is even better.

[0099] As can be seen from Example 1 and Comparative Example 3, when no carbon fiber is added, the flexural modulus of the obtained product is only 2680 MPa, the heat distortion temperature is only 140°C, and the notched impact strength of the simply supported beam is also significantly reduced to only 5.0 KJ / m. 2 As can be seen from Example 1 and Comparative Example 5, when the carbon fiber surface does not contain PET resin but PU resin, the heat resistance of the obtained product is significantly reduced, the heat distortion temperature is only 205℃, and the notched impact strength of the simply supported beam of the product also shows a downward trend. As can be seen from Example 1 and Comparative Examples 6-7, when the mass percentage of PET resin on the carbon fiber surface is not within the range given in this invention, the mechanical properties of the obtained product are significantly worse.

[0100] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PET composite material, characterized in that, The PET composite material comprises the following components in parts by weight: The first component consists of 38-82 parts PET resin, 8-42 parts carbon fiber, 0.5-6.5 parts toughening agent, and 0.05-1.1 parts nucleating agent. The carbon fiber surface contains 1-4% by mass of a second PET resin, based on the mass of the carbon fiber. The nucleating agent comprises a long-chain saturated linear carboxylate, wherein the long-chain saturated linear carboxylate has 22-28 carbon atoms.

2. The PET composite material according to claim 1, characterized in that, The PET composite material comprises the following components in parts by weight: The first component consists of 60-70 parts of PET resin, 20-30 parts of carbon fiber, 2-4 parts of toughening agent, and 0.2-0.6 parts of nucleating agent.

3. The PET composite material according to claim 1, characterized in that, The carbon fiber surface contains 2.2-3.8% by mass of a second PET resin, based on the mass of the carbon fiber.

4. The PET composite material according to claim 1, characterized in that, The nucleating agent further includes ultrafine talc powder; preferably, the mass ratio of long-chain saturated linear carboxylate to ultrafine talc powder in the nucleating agent is (1-3):

1.

5. The PET composite material according to claim 1, characterized in that, The intrinsic viscosity of the first PET resin and the second PET resin are each independently 0.56-0.92 dL / g.

6. The PET composite material according to claim 1, characterized in that, The long-chain saturated linear carboxylate includes at least one of calcium octadecanoate and sodium docosanoate.

7. The PET composite material according to claim 1, characterized in that, The toughening agent includes at least one of ethylene-based terpolymers, ethylene-octene elastomers, and ethylene-butene elastomers.

8. The PET composite material according to claim 1, characterized in that, The PET composite material also includes 0.1-5 parts of processing aids.

9. The method for preparing the PET composite material according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: weighing the dried raw materials and mixing them, feeding them into a twin-screw extruder, and extruding, stretching, cooling, pelletizing and drying to obtain a PET composite material.

10. The application of the PET composite material as described in any one of claims 1-8 in the preparation of automotive interior structures and weapon rack materials.

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