Low-warpage heat-resistant PETG / PBAT composition and preparation method and application thereof

Abstract

The invention discloses a low-warping heat-resistant PETG / PBAT composition and a preparation method and application thereof, and belongs to the technical field of flooring materials. The composition comprises the following components in parts by weight: 50 to 80 parts of PETG resin; 10 to 40 parts of PBAT resin; 30 to 80 parts of calcium carbonate; 10 to 30 parts of modified fly ash; 0.5 to 3 parts of a coupling agent; 1-5 parts of a compatilizer; and 0.5-3 parts of a transesterification inhibitor. The preparation process provided by the invention is simple, the production cost is low, and the composition has good warpage shrinkage, heat resistance and rigid-tough balance performance, and can be applied to multiple fields such as wallboards, indoor floors, outdoor floors, household table tops and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of floor materials, and more specifically, relates to a low-warpage heat-resistant PETG / PBAT composition, a preparation method thereof, and an application thereof. Background Art

[0002] For traditional solid wood and composite floors, the layered structure thereof is prone to generate moisture absorption expansion differences during humidity fluctuations, resulting in three-dimensional warping deformation. Moreover, the dry shrinkage effect of the wood components and the creep characteristics of the adhesive in a high-temperature environment will further exacerbate the deformation degree. In particular, the difference in the thermal expansion coefficients between the alumina wear-resistant layer on the surface of the laminate floor and the substrate is likely to cause an interfacial peeling phenomenon under continuous heat radiation. Although the PVC elastic floor has moisture-proof characteristics, when heated above 60 °C, the molecular chain segments move more intensively, and irreversible dimensional shrinkage and surface depression often occur. These material defects not only affect the paving flatness, but also reduce the safety and service life of the ground system.

[0003] Existing resin-based composite material floors (such as PET, ABS, and polyester sheets) still have significant defects in terms of thermal stability and dimensional retention. Although the PET material has the characteristic of light weight, its glass transition temperature (Tg) is between 70 °C and 80 °C. The rearrangement of molecular chain segments at high temperatures is likely to cause local softening and stress relaxation, resulting in warping at the edges of the floor and surface depression. The ABS-based sheets are prone to creep deformation under continuous heat load (>55 °C), and the insufficient rigidity causes wavy undulations at the joints. In some composite floors, due to the mismatch of the thermal expansion coefficients between the reinforcing fibers and the resin matrix, interfacial microcracks will be generated during temperature cycling, accelerating delamination failure. In addition, the anisotropic expansion of polyester materials after moisture absorption will be coupled with thermally induced deformation, further reducing the structural reliability of the floor in the scenario of coupled heat and humidity.

[0004] PETG is a semi-crystalline plastic copolymerized from two main components, terephthalic acid and ethylene glycol. Compared with traditional PET, PETG has higher toughness, transparency, and impact resistance, and is a transparent or semi-transparent polymer material. Since a 1,4-cyclohexanedimethanol (CHDM) copolymer unit is introduced into the PETG molecular chain, the crystallinity of PET is destroyed, forming an amorphous polymer. In the amorphous structure, the molecular chains are arranged disorderly, and the intermolecular forces are weak. The chain segments are more likely to move at high temperatures, resulting in material softening; the ester groups in the molecular chains are prone to react with water molecules at high temperatures, causing hydrolysis, further reducing the molecular weight, and accelerating the performance deterioration. In addition, the high price of PETG resin further limits its application in multiple fields.

[0005] For example, when using pure PETG material as the floor substrate, its thermomechanical properties and dimensional stability still have obvious shortcomings. When the ambient temperature approaches Tg, the movement of molecular chain segments intensifies, resulting in a sharp drop in the storage modulus. Under continuous thermal load (such as in a floor heating environment), thermal creep is likely to occur, manifested as the middle of the board sinking and the edges warping upwards. At the same time, although its amorphous structure endows it with isotropic shrinkage characteristics, if the cooling gradient is not properly controlled during injection molding, the release of internal residual stress will cause non-uniform warping deformation. In addition, although the moisture absorption rate of PETG is lower than that of ABS (about 0.15%), long-term exposure to a high-humidity environment will still cause slight swelling, which will form dynamic deformation accumulation after coupling with the thermal shrinkage effect. Under low-temperature conditions (<10 °C), the fracture toughness of PETG decreases significantly, and local impact is likely to cause the propagation of microcracks, further weakening the structural reliability of the floor. Although the PETG / ABS and PETG / PP alloy systems have improved some mechanical properties through blending modification, they still face application bottlenecks in a thermo-humid coupling environment.

[0006] At the same time, composite floors also have problems such as interfacial stress concentration caused by compatibility and induced edge curling; weak interfacial bonding force, which is prone to cracking along the weld line under thermomechanical loads, further reducing the structural durability of the floor; and the problem of expensive materials and high costs. Summary of the Invention

[0007] The object of the present invention is to address the above deficiencies, solve the problem of easy warping and deformation of existing floor materials in a humid and hot environment, and provide a low-warpage heat-resistant PETG / PBAT composition, its preparation method and application. The preparation process is simple, the production cost is low, the composition has good warping shrinkage, heat resistance and rigid-flexible balance performance, and can be applied in multiple fields such as wall panels, indoor floors, outdoor floors, and home countertops.

[0008] To achieve the above object, the present invention is realized through the following technical solutions: In the first aspect, the present invention provides a low-warpage heat-resistant PETG / PBAT composition. The raw materials of the composition include resin, filler and reaction aids. The resin, filler and reaction aids include the following components in parts by weight: PETG resin: 50 parts to 80 parts; PBAT resin: 10 parts to 40 parts; Calcium carbonate: 30 parts to 80 parts; Modified fly ash: 10 parts to 30 parts; Coupling agent: 0.5 parts to 3 parts; Compatibilizer: 1 part to 5 parts; Ester exchange inhibitor: 0.5 parts to 3 parts.

[0009] Preferably, the PETG resin has a melt index of 2 g / 10min to 5 g / 10min under the test conditions of 250 °C and 2.16 kg; the content of 1,4-cyclohexanedimethanol in the PETG resin is 20 wt% to 45 wt%.

[0010] Preferably, the PBAT resin has a melt index of 4 g / 10min to 6 g / 10min under the test conditions of 190 °C and 2.16 kg.

[0011] PBAT resin, namely poly(butylene adipate-co-terephthalate), is a common biodegradable thermoplastic polyester with excellent biodegradability, friendly to the environment, and can effectively reduce white pollution. PBAT has relatively high tensile strength and elongation at break, and its mechanical properties are similar to those of traditional plastics such as polyethylene and polypropylene, and even better in some aspects. The products made have good toughness and tear resistance. However, PBAT has problems such as low modulus and poor heat resistance, and currently only has a certain market in the field of film bags. In the present invention, PBAT resin is introduced to be blended and compounded with PETG to replace the more expensive toughening agent, improve the toughness and impact strength of the material, and reduce the cost at the same time.

[0012] Preferably, the particle size of the calcium carbonate is 200 - 1500 mesh; using calcium carbonate with a low mesh number as a filler can effectively reduce the product cost and increase the dimensional stability of the material at the same time.

[0013] Preferably, the modified fly ash is prepared by surface coating modification of primary ash through chemical activation.

[0014] Fly ash, as the main solid waste discharged from coal-fired power plants, is formed by fine ash collected from the flue gas after coal combustion. However, due to its smooth surface, its compatibility with the polymer matrix is poor, so the interface between fly ash and the matrix may become a weak link in the composite material; fly ash has a dull color and a whiteness of only about 30, which cannot meet the requirements of light-colored fillers; in addition, the Vickers hardness of fly ash is above 1000, exceeding the 38CrMoAl alloy steel material used for the barrel and screw of general extruders, and the wear of the metal parts in contact with the polymer filled with fly ash is relatively serious. The inherent defects of fly ash itself restrict its application in polymers. Even if the specific surface area of fly ash is increased by using strong alkali or strong acid solutions such as sodium hydroxide and hydrochloric acid, it is difficult to improve the appearance color of fly ash.

[0015] In this application, surface-coated modified fly ash is used as a filler to improve its compatibility with the polymer, form more stable chemical bonds with the resin molecular chains, effectively increase the heat distortion temperature of the material, and save energy and protect the environment while reducing the cost.

[0016] Preferably, the coupling agent is at least one of titanate coupling agent and aluminate coupling agent. Adding an appropriate amount of coupling agent can improve the dispersibility of the filler, enhance the interfacial bonding force, and improve the mechanical properties of the composite material.

[0017] Preferably, the compatibilizer is at least one of PE-g-MAH (maleic anhydride grafted polyethylene), PP-g-MAH (maleic anhydride grafted polypropylene), ethylene-acrylate glycidyl methacrylate, SEBS-g-MAH (maleic anhydride grafted styrene-ethylene-butene-styrene block copolymer), and POE-g-GMA (glycidyl methacrylate grafted polyolefin elastomer). Adding an appropriate amount of compatibilizer can promote dispersion, reduce the interfacial tension, enhance the interfacial bonding force, and improve the mechanical properties and processing properties of the material.

[0018] Preferably, the transesterification inhibitor is at least one of triphenyl phosphite, sodium dihydrogen phosphate, or disodium dihydrogen pyrophosphate. Adding an appropriate amount of transesterification inhibitor can prevent the transesterification between PETG and PBAT, thereby preventing the destruction of the molecular chain structure caused by the transesterification reaction, maintaining the molecular chain structure stability, and preventing degradation or deterioration of the material properties; an excessive amount of the inhibitor may affect the processing properties of the material or introduce impurities.

[0019] Preferably, the raw materials of the composition further include 0.1 part to 2 parts of antioxidant and / or 0.1 part to 2 parts of lubricant. The antioxidant is one of hindered phenol antioxidants or phosphite antioxidants; the lubricant is one of vinyl bisstearamide, polysiloxane, calcium stearate, magnesium stearate, zinc stearate, PE wax, PP wax, ethylene bisstearamide, or fatty acid ester. An appropriate amount of antioxidant can avoid the molecular chain breakage (degradation) or crosslinking (hardening) caused by oxidation by blocking the free radical chain reaction or decomposing peroxides, and delay the aging of the material; an appropriate amount of lubricant can improve the processing fluidity, reduce the processing energy consumption, improve the production efficiency, prevent extrusion adhesion, and improve the demoulding property and the surface finish of the material.

[0020] In a second aspect, the present invention provides a method for preparing the low warpage heat-resistant PETG / PBAT composition described in the first aspect, including: Drying the PETG resin, PBAT resin, calcium carbonate, and fly ash; Surface coating and modifying the dried fly ash by chemical activation to obtain modified fly ash; Mixing the dried PETG resin, PBAT resin, calcium carbonate, and modified fly ash with the reaction assistant in proportion and uniformly to obtain a mixture; Melting, blending, and extruding the above mixture to obtain the PETG / PBAT composition.

[0021] Preferably, the PETG resin and PBAT resin are dried at 60° C. to 80° C. for 6 h to 12 h; and the calcium carbonate and fly ash are dried at 80° C. to 130° C. for 1 h to 2 h by a high-speed mixer.

[0022] Preferably, the dried fly ash is subjected to surface coating modification by chemical excitation to obtain modified fly ash, comprising: Place fly ash and calcium hydroxide solution in an open reactor, stir thoroughly to make the slurry evenly mixed, heat to 60℃~95℃, and keep warm for 2h~3h; The reaction is terminated by introducing carbon dioxide gas until the pH value is 7, and the reaction slurry is filtered and dried to obtain the modified fly ash.

[0023] Further preferably, the mass ratio of the fly ash to the calcium hydroxide solution is 1:10, the concentration of the calcium hydroxide solution is 7 wt %; and the rate of introducing carbon dioxide gas is 0.15 L / min.

[0024] According to the fly ash activity excitation principle, the nano-silicate components generated by the reaction will be deposited and grown on the surface of the fly ash particles as sub-particles to form a coating layer. The subsequent introduction of a mixed gas of air and carbon dioxide can neutralize the residual calcium hydroxide in the slurry.

[0025] Preferably, the mixed material is melted, blended and extruded by a twin-screw extruder; The blending temperature is 80°C to 120°C, the mixing time is 10 min to 30 min, and the rotation speed is 300 r / min to 400 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are: zone 1 to zone 3 feeding section, continuous feeding, the temperature is set to 150°C ~ 190°C; zone 4 to zone 5 melting section, the material is heated as a whole to form a molten state, the temperature is set to 180°C ~ 190°C; zone 6 to zone 7 plasticizing section, plasticizing the material, the temperature is set to 190°C ~ 205°C; zone 8 exhaust section, excess pores in the melt are discharged, the temperature is set to 190°C ~ 205°C; zone 9 to zone 10 mixing section, fully mixing the raw materials, the temperature is set to 190°C ~ 205°C; zone 11 to zone 12 extrusion section, after the material inside the twin-screw extruder is extruded, the temperature is set to 190°C ~ 200°C.

[0026] In a third aspect, the present invention further provides the use of the low-warpage heat-resistant PETG / PBAT composition described in the first aspect in wall panels, indoor floors, outdoor floors, and home countertops.

[0027] Compared with the prior art, the present invention has the following beneficial effects: The low-warpage heat-resistant PETG / PBAT composition of the present invention reduces the use of toughening agents by introducing PBAT into the PETG filling system, further reduces the cost of the composite material by adding modified fly ash, selects suitable reaction aids and sets a specific ratio, fills inorganic powders in the gaps between molecular chains, increases the resistance to chain segment movement, and improves the rigidity of the material, and the main components of fly ash SiO2 (40%-60%) and Al2O3 (20%-30%) have a high melting point (>1500°C), form a heat insulation barrier, and hinder the transfer of heat to the matrix; through the synergistic effect of various components, the heat-resistant temperature of the material is increased, the warpage shrinkage and thermal expansion coefficient of the product are improved, and the application of PETG in the fields of building materials is expanded; and the raw material cost is low, industrial waste is recycled and modified, and energy conservation and environmental protection are achieved.

[0028] The preparation method of the invention has simple process and low production cost. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0030] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0031] The raw materials used in the following examples and comparative examples are as follows: PETG resin: 1,4-cyclohexanedimethanol has a mass percentage of 30% and a melt index of 2-5 g / 10 min, Henan Yinjinda New Materials Co., Ltd. PBAT resin: intrinsic viscosity 2.5dl / g, Zhejiang Huafeng Group Co., Ltd.; Calcium carbonate: 325 mesh calcium carbonate, Quanzhou Xufeng Powder Raw Material Co., Ltd.; Fly ash; first-grade ash, Jining Hengzhi New Building Materials Co., Ltd.; Calcium hydroxide solution: 7% mass concentration, homemade; Coupling agent: aluminate coupling agent, NXH-821, Nanjing Xuanhao New Material Technology Co., Ltd.; Compatibilizer: POE-g-GMA, W5D, Coais Chemical Co., Ltd. Transesterification inhibitor: disodium dihydrogen pyrophosphate, Hubei Xingfa Chemical Group Co., Ltd.; Antioxidant: Hindered phenol antioxidant, RIANOX 1010; Lubricant: EBS (ethylene bisstearamide), WAX 2200, Changzhou Kesai Chenggong Plastic Materials Co., Ltd.

[0032] The present invention will be described in detail below in conjunction with examples and comparative examples.

[0033] Example 1: This example provides a low-warpage heat-resistant PETG / PBAT composition, the ingredient list of which is shown in Table 1, and its preparation method includes the following steps: S1: Dry the PETG and PBAT resins at 70 °C for 6 h to remove their own moisture, and dry calcium carbonate and fly ash separately in a high-speed mixer at 80 °C for 1 h, and set aside.

[0034] S2: Add fly ash to a 7 wt% calcium hydroxide suspension and place it in an open reaction kettle, stir well to make the pulp evenly mixed, heat up to 60 °C, and keep warm for 2 h; wherein, the mass ratio of fly ash to calcium hydroxide suspension is 1:10. According to the principle of fly ash activity excitation, the nano-silicate component generated by the reaction will deposit and grow on the surface of fly ash particles to form a coating film layer. Subsequently, carbon dioxide gas is introduced at a speed of 0.15 L / min to neutralize the residual calcium hydroxide in the pulp. When the pH = 7, the reaction ends, and the slurry is filtered and dried to obtain modified fly ash for standby.

[0035] S3: Weigh PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant, and transesterification inhibitor in proportion and mix them evenly to obtain a mixture.

[0036] S4: Add the mixture in step S3 to a twin-screw extruder through the feeding port, and after melting, blending, and extrusion, the PETG / PBAT composition is processed.

[0037] In step S4, the blending temperature is 80 °C, mixing for 10 min, and the rotation speed is 300 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are: feeding sections in zones 1 to 3 for continuous feeding, with temperatures set at 150°C, 160°C and 170°C respectively; melting sections in zones 4 to 5 for heating the material as a whole to form a molten state, with temperatures set at 180°C and 185°C respectively; plasticizing sections in zones 6 to 7 for plasticizing the material to reduce the hardness of the material, improve the toughness of the material, and increase the ductility and plasticity of the material, with temperatures set at 190°C and 195°C respectively; exhaust section in zone 8 for exhausting excess pores in the melt, with a temperature set at 195°C; mixing sections in zones 9 to 10 for fully mixing the raw materials, with temperatures set at 195°C and 200°C respectively; extrusion sections in zones 11 to 12 for extruding the material inside the twin-screw extruder equipment to form a floor base shape, with temperatures set at 195°C and 200°C respectively.

[0038] Embodiment 2: This embodiment provides a low-warpage heat-resistant PETG / PBAT composition, the ingredients of which are shown in Table 1, and the preparation method thereof comprises the following steps: S1: Dry PETG and PBAT resins at 80°C for 12 h to remove their own moisture, and dry calcium carbonate and fly ash at 130°C for 2 h in a high-speed mixer for later use.

[0039] S2: Add fly ash to 7wt% calcium hydroxide suspension and place it in an open reactor, stir it thoroughly to make the slurry evenly mixed, heat it to 95℃, and keep it warm for 3 hours; the mass ratio of fly ash to calcium hydroxide suspension is 1 to 10. According to the principle of fly ash activity excitation, the nano-silicate components generated by the reaction will be deposited and grown on the surface of fly ash particles as sub-particles to form a coating layer. Then, carbon dioxide gas is introduced at a rate of 0.15L / min to neutralize the residual calcium hydroxide components in the slurry. The reaction ends when pH=7, and the slurry is filtered and dried to obtain modified fly ash for use.

[0040] S3: PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant and transesterification inhibitor are weighed in proportion and uniformly mixed to obtain a mixture.

[0041] S4: adding the mixed material in step S3 into a twin-screw extruder through a feed port, and processing to obtain the PETG / PBAT composition after melting, blending and extrusion.

[0042] In step S4, the blending temperature is 120° C., the mixing time is 30 min, and the speed is 400 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are in sequence: the feeding section in zones 1-3, with continuous feeding, and the temperatures are set at 150 °C, 160 °C, and 170 °C respectively; the melting section in zones 4-5, for overall heating of the material to form a molten state, and the temperatures are set at 180 °C and 185 °C respectively; the plasticizing section in zones 6-7, for plasticizing the material, thereby reducing the hardness of the material, improving the toughness of the material, increasing the ductility and plasticity of the material, and the temperatures are set at 190 °C and 195 °C respectively; the exhaust section in zone 8, for discharging the excess pores in the melt, and the temperature is set at 195 °C; the mixing section in zones 9-10, for fully mixing the raw materials, and the temperatures are set at 195 °C and 200 °C respectively; the extrusion section in zones 11-12, after extruding the material inside the twin-screw extrusion equipment, forming the shape of a floor base, and the temperatures are set at 195 °C and 200 °C respectively.

[0043] Example 3: This example provides a low-warpage heat-resistant PETG / PBAT composition, and its ingredient list is shown in Table 1. Its preparation method includes the following steps: S1: Dry the PETG and PBAT resins at 70 °C for 10 h to remove their own moisture. Calcium carbonate and fly ash are dried by a high-speed mixer at 120 °C for 1.5 h respectively and reserved.

[0044] S2: Add fly ash to a 7 wt% calcium hydroxide suspension and place it in an open reaction kettle. Stir well to make the pulp evenly mixed, heat up to 80 °C, and keep warm for 2.5 h; among them, the mass ratio of fly ash to the calcium hydroxide suspension is 1:10. According to the principle of fly ash activity excitation, the nano-silicate components generated by the reaction will deposit and grow on the surface of fly ash particles to form a coating film layer. Subsequently, carbon dioxide gas is introduced at a speed of 0.15 L / min to neutralize the residual calcium hydroxide in the pulp. When pH = 7, the reaction ends, and the slurry is filtered and dried to obtain modified fly ash for standby.

[0045] S3: Weigh the PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant, and transesterification inhibitor in proportion and mix them evenly to obtain a mixture.

[0046] S4: Add the mixture in step S3 to the twin-screw extruder through the feeding port, and after melting, blending, and extruding, process to obtain the PETG / PBAT composition.

[0047] In the step S4, the blending temperature is 100 °C, mixing for 20 min, and the rotation speed is 350 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are: feeding sections in zones 1 to 3 for continuous feeding, with temperatures set at 150°C, 160°C and 170°C respectively; melting sections in zones 4 to 5 for heating the material as a whole to form a molten state, with temperatures set at 180°C and 185°C respectively; plasticizing sections in zones 6 to 7 for plasticizing the material to reduce the hardness of the material, improve the toughness of the material, and increase the ductility and plasticity of the material, with temperatures set at 190°C and 195°C respectively; exhaust section in zone 8 for exhausting excess pores in the melt, with a temperature set at 195°C; mixing sections in zones 9 to 10 for fully mixing the raw materials, with temperatures set at 195°C and 200°C respectively; extrusion sections in zones 11 to 12 for extruding the material inside the twin-screw extruder equipment to form a floor base shape, with temperatures set at 195°C and 200°C respectively.

[0048] Embodiment 4: This embodiment provides a low-warpage heat-resistant PETG / PBAT composition, the ingredients of which are shown in Table 1, and the preparation method thereof comprises the following steps: S1: PETG and PBAT resins were dried at 65°C for 11 hours to remove their own moisture, and calcium carbonate and fly ash were dried at 125°C for 1.5 hours by a high-speed mixer and set aside.

[0049] S2: Add fly ash to 7wt% calcium hydroxide suspension and place it in an open reactor, stir it thoroughly to make the slurry evenly mixed, heat it to 75℃, and keep it warm for 3 hours; the mass ratio of fly ash to calcium hydroxide suspension is 1 to 10. According to the principle of fly ash activity excitation, the nano-silicate components generated by the reaction will be deposited and grown on the surface of fly ash particles as sub-particles to form a coating layer. Then, carbon dioxide gas is introduced at a rate of 0.15L / min to neutralize the residual calcium hydroxide components in the slurry. The reaction ends when pH=7, and the slurry is filtered and dried to obtain modified fly ash for use.

[0050] S3: PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant and transesterification inhibitor are weighed in proportion and uniformly mixed to obtain a mixture.

[0051] S4: adding the mixed material in step S3 into a twin-screw extruder through a feed port, and processing to obtain the PETG / PBAT composition after melting, blending and extrusion.

[0052] In step S4, the blending temperature is 90°C, the mixing time is 15 min, and the rotation speed is 320 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are: feeding sections in zones 1 to 3 for continuous feeding, with temperatures set at 150°C, 160°C and 170°C respectively; melting sections in zones 4 to 5 for heating the material as a whole to form a molten state, with temperatures set at 180°C and 185°C respectively; plasticizing sections in zones 6 to 7 for plasticizing the material to reduce the hardness of the material, improve the toughness of the material, and increase the ductility and plasticity of the material, with temperatures set at 190°C and 195°C respectively; exhaust section in zone 8 for exhausting excess pores in the melt, with a temperature set at 195°C; mixing sections in zones 9 to 10 for fully mixing the raw materials, with temperatures set at 195°C and 200°C respectively; extrusion sections in zones 11 to 12 for extruding the material inside the twin-screw extruder equipment to form a floor base shape, with temperatures set at 195°C and 200°C respectively.

[0053] Embodiment 5: This embodiment provides a low-warpage heat-resistant PETG / PBAT composition, the ingredients of which are shown in Table 1, and the preparation method thereof comprises the following steps: S1: Dry PETG and PBAT resins at 75°C for 10.5 h to remove their own moisture. Dry calcium carbonate and fly ash at 85°C for 2 h in a high-speed mixer and set aside.

[0054] S2: Add fly ash to 7wt% calcium hydroxide suspension and place it in an open reactor, stir it thoroughly to make the slurry evenly mixed, heat it to 70℃, and keep it warm for 2.5h; the mass ratio of fly ash to calcium hydroxide suspension is 1 to 10. According to the principle of fly ash activity excitation, the nano-silicate components generated by the reaction will be deposited and grown on the surface of fly ash particles as sub-particles to form a coating layer. Then, carbon dioxide gas is introduced at a rate of 0.15L / min to neutralize the residual calcium hydroxide components in the slurry. The reaction ends when pH=7, and the slurry is filtered and dried to obtain modified fly ash for use.

[0055] S3: PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant and transesterification inhibitor are weighed in proportion and uniformly mixed to obtain a mixture.

[0056] S4: adding the mixed material in step S3 into a twin-screw extruder through a feed port, and processing to obtain the PETG / PBAT composition after melting, blending and extrusion.

[0057] In step S4, the blending temperature is 95°C, the mixing time is 20 min, and the speed is 350 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are in sequence: the feeding section in zones 1 - 3, with continuous feeding, and the temperatures are set at 150°C, 160°C, and 170°C respectively; the melting section in zones 4 - 5, for overall heating of the material to form a molten state, and the temperatures are set at 180°C and 185°C respectively; the plasticizing section in zones 6 - 7, for plasticizing the material, thereby reducing the hardness of the material, increasing the toughness of the material, and enhancing the ductility and plasticity of the material, and the temperatures are set at 190°C and 195°C respectively; the exhaust section in zone 8, for discharging excess pores in the melt, and the temperature is set at 195°C; the mixing section in zones 9 - 10, for fully mixing the raw materials, and the temperatures are set at 195°C and 200°C respectively; the extrusion section in zones 11 - 12, for extruding the material inside the twin-screw extrusion equipment to form the shape of a floor base, and the temperatures are set at 195°C and 200°C respectively.

[0058] Example 6: This example provides a low-warpage heat-resistant PETG / PBAT composition, and its ingredient list is shown in Table 1. Its preparation method includes the following steps: S1: Dry the PETG and PBAT resins at 75°C for 10 h to remove their own moisture. Calcium carbonate and fly ash are dried by a high-speed mixer at 120°C for 1.5 h respectively and set aside.

[0059] S2: Add fly ash to a 7 wt% calcium hydroxide suspension in an open reaction kettle, fully stir to make the pulp evenly mixed, heat up to 80°C, and keep warm for 2 h; among them, the mass ratio of fly ash to the calcium hydroxide suspension is 1:10. According to the principle of fly ash activity excitation, the nano-silicate components generated by the reaction will deposit and grow on the surface of fly ash particles to form a coating film layer. Subsequently, carbon dioxide gas is introduced at a speed of 0.15 L / min to neutralize the residual calcium hydroxide in the pulp. When pH = 7, the reaction ends, and the slurry is filtered and dried to obtain modified fly ash for standby.

[0060] S3: Weigh the PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant, and transesterification inhibitor in proportion and mix them evenly to obtain a mixture.

[0061] S4: Add the mixture in step S3 to the twin-screw extruder through the feeding port, and after melting, blending, and extrusion, the PETG / PBAT composition is processed.

[0062] In the above step S3, the blending temperature is 110°C, mixing time is 20 min, and rotation speed is 300 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are in sequence: the feeding section in zones 1 - 3, with continuous feeding, and the temperatures are set at 150 °C, 160 °C, and 170 °C respectively; the melting section in zones 4 - 5, for overall heating of the material to form a molten state, and the temperatures are set at 180 °C and 185 °C respectively; the plasticizing section in zones 6 - 7, for plasticizing the material, thereby reducing the hardness of the material, improving the toughness of the material, increasing the ductility and plasticity of the material, and the temperatures are set at 190 °C and 195 °C respectively; the exhaust section in zone 8, for discharging the excess pores in the melt, and the temperature is set at 195 °C; the mixing section in zones 9 - 10, for fully mixing the raw materials, and the temperatures are set at 195 °C and 200 °C respectively; the extrusion section in zones 11 - 12, for extruding the material inside the twin-screw extrusion equipment to form the shape of a floor base, and the temperatures are set at 195 °C and 200 °C respectively.

[0063] Example 7: This example provides a low-warpage heat-resistant PETG / PBAT composition, and its ingredient list is shown in Table 1. Its preparation method includes the following steps: S1: Dry the PETG and PBAT resins at 75 °C for 10 h to remove their own moisture. Calcium carbonate and fly ash are dried at 120 °C for 2 h respectively through a high-speed mixer and set aside.

[0064] S2: Add fly ash to a 7 wt% calcium hydroxide suspension and place it in an open reaction kettle. Stir well to make the pulp evenly mixed, heat up to 90 °C, and keep warm for 2 h. Among them, the mass ratio of fly ash to the calcium hydroxide suspension is 1:10. According to the principle of fly ash activity excitation, the nano-silicate component generated by the reaction will deposit and grow on the surface of fly ash particles to form a coating film layer. Subsequently, carbon dioxide gas is introduced at a speed of 0.15 L / min to neutralize the residual calcium hydroxide in the pulp. When pH = 7, the reaction ends, and the slurry is filtered and dried to obtain modified fly ash for standby.

[0065] S3: Weigh the PETG resin, PBAT resin, calcium carbonate, modified fly ash, coupling agent, lubricant, antioxidant, and transesterification inhibitor in proportion and mix them evenly to obtain a mixture.

[0066] S4: Add the mixture in step S3 to the twin-screw extruder through the feeding port, and after melting, blending, and extrusion, the PETG / PBAT composition is processed.

[0067] In the step S3, the blending temperature is 100 °C, mixing is carried out for 20 min, and the rotation speed is 350 r / min; The twin-screw extruder is provided with 12 temperature setting zones, which are in sequence: the feeding sections of zones 1 to 3, with continuous feeding, and the temperatures are set at 150 °C, 160 °C, and 170 °C respectively; the melting sections of zones 4 to 5, for overall heating of the material to form a molten state, and the temperatures are set at 180 °C and 185 °C respectively; the plasticizing sections of zones 6 to 7, for plasticizing the material, thereby reducing the hardness of the material, improving the toughness of the material, increasing the ductility and plasticity of the material, and the temperatures are set at 190 °C and 195 °C respectively; the exhaust section of zone 8, for discharging the excess pores in the melt, and the temperature is set at 195 °C; the mixing sections of zones 9 to 10, for sufficient mixing of the raw materials, and the temperatures are set at 195 °C and 200 °C respectively; the extrusion sections of zones 11 to 12, for extruding the material inside the twin-screw extrusion equipment to form the shape of a floor base, and the temperatures are set at 195 °C and 200 °C respectively.

[0068] The component dosages of the above-mentioned respective embodiments are shown in Table 1.

[0069] Table 1: Dosages of each component in Examples 1 to 7 (parts by weight) 。

[0070] Comparative Example 1: A PETG / PBAT composition, the ingredient list thereof is shown in Table 2, and its preparation method is the same as that of Example 1.

[0071] Comparative Example 2: A PETG / PBAT composition, the ingredient list thereof is shown in Table 2, and its preparation method does not include the preparation of modified fly ash, and the rest is the same as that of Example 1.

[0072] Comparative Example 3: A PETG / PBAT composition, the ingredient list thereof is shown in Table 2, and its preparation method is the same as that of Example 1.

[0073] Comparative Example 4: A PETG / PBAT composition, the ingredient list thereof is shown in Table 2, and its preparation method is the same as that of Example 1.

[0074] Comparative Example 5: A PETG / PBAT composition, the ingredient list thereof is shown in Table 2, and its preparation method is the same as that of Example 1.

[0075] Table 2: Dosages of each component in Comparative Examples 1 to 5 (parts by weight) 。

[0076] The PETG / PBAT compositions prepared from the above-mentioned examples and comparative examples are subjected to the following performance tests, and the reference standards and methods for the tests are as follows: Melt flow rate: Tested according to the standard of GB / T 3682-2018. The PETG / PBAT composition particles were tested using a melt flow tester that complies with this standard. The test temperature was 190 °C, the pressure load was 2.16 kg, and the cutting time was 30 s.

[0077] Flexural strength and flexural modulus: Tested according to the standard of GB / T 3341-2008. The PETG / PBAT composition was used to prepare test specimens with dimensions of 80 mm×10 mm×4 mm. The samples were placed on a testing machine that complies with the standard of GB / T 17200-1997 for flexural strength and flexural modulus testing.

[0078] Tensile strength and elongation at break: Tested according to the standard of GB / T 1040-2018. The PETG / PBAT composition was used to prepare 1A dumbbell-shaped test specimens specified in this standard and tested using a testing machine that complies with the regulations in GB / T 16825.1-2008 and GB / T 12160-2002.

[0079] Izod notched impact: Tested according to the standard of GB / T 1843-2008. The PETG / PBAT composition was used to prepare test specimens with dimensions of 80 mm×10 mm×4 mm and a notch depth of 2 mm. The Izod notched impact strength was tested using a testing machine that complies with the standard of GB / T 21189-2007.

[0080] Heat distortion temperature: Tested according to the standard of GB / T 1643.2-2019. The PETG / PBAT composition was used to prepare test specimens with dimensions of 80 mm×10 mm×4 mm. The heat distortion temperature was tested using a heating device and weights that comply with this standard.

[0081] Warpage: Tested according to the ISO 24342 standard. The PETG / PBAT composition was used to prepare square test samples with dimensions of 250 mm×250 mm. The samples were placed on a flat tabletop, and the four corners of the samples were tested one by one with a feeler gauge. The maximum value among the four corners was selected as the test result.

[0082] Shrinkage rate: Tested according to ISO 24342 standard. Prepare a 250 mm×250 mm square test sample from the PETG / PBAT composition, measure the length and width of the sample (measure and record the data for all four sides, record the length as L10, L20, and the width as W10, W20), place the sample in an 80 °C oven, take it out after 6 h and let it stand in the laboratory for 3 h, and then measure the length and width of the test sample after standing (record the length as L11, L21, and the width as W11, W21). Calculate: for length: [(L11 + L21) / 2 - (L10 + L20) / 2] / [(L10 + L20) / 2]; for width: [(W11 + W21) / 2 - (W10 + W20) / 2] / [(W10 + W20) / 2], and select the maximum value of the test results.

[0083] Coefficient of thermal expansion: Tested according to GB / T36800.2-2018 standard. Prepare a rectangular test sample with a length of 5 - 10 mm and a width of 5 mm from the PETG / PBAT composition, calibrate the instrument according to the requirements of ISO 11359-1, and conduct the coefficient of thermal expansion test.

[0084] Test the PETG / PBAT compositions obtained in Examples 1 - 7 and Comparative Examples 1 - 5, and the test results are shown in Table 3 and Table 4.

[0085] Table 3: Performance test results of PETG / PBAT compositions prepared in Examples 1 - 7 。

[0086] Table 4: Performance test results of PETG / PBAT compositions prepared in Comparative Examples 1 - 5 。

[0087] From the comparison of the above test data, it can be seen that: From the test results of Examples 1 - 3 and Comparative Example 1, blending PBAT with PBAT can effectively increase the toughness of the material and improve the impact strength of the material, but too high a proportion of PBAT will lead to a decrease in flexural strength, flexural modulus and tensile strength.

[0088] From the test results of Examples 4 - 5 and Comparative Example 2, the addition of fly ash forms more stable chemical bonds with the resin molecular chains, effectively improving the heat distortion temperature of the material.

[0089] From the test result of Comparative Example 3, the absence of a coupling agent will cause the powder to agglomerate, and at the same time reduce the interfacial bonding force with the resin, resulting in the deterioration of the material properties; from the test results of Example 6 and Comparative Example 4, the absence of a compatibilizer or too little compatibilizer will cause phase separation in the composite system, resulting in a decrease in the material properties and easy cracking.

[0090] From the test results of Example 7 and Comparative Example 5, it can be seen that the absence or small amount of transesterification inhibitor will cause transesterification between PETG and PBAT, resulting in the deterioration of material properties.

[0091] In summary, a low-warpage heat-resistant PETG / PBAT composition, its preparation method and application proposed by the present invention have a simple preparation process and low production cost. The PETG / PBAT composition has good warpage shrinkage, heat resistance and balance of rigidity and toughness, and can be applied in many fields such as wall panels, indoor floors, outdoor floors, and household countertops.

[0092] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and technical principles of the described embodiments, and these modifications and changes should also be regarded as the protection scope of the present invention.

Claims

1. A low-warpage heat-resistant PETG / PBAT composition, characterized in that, The raw materials of the composition include resin, filler and reaction aids, and the resin, filler and reaction aids include the following components in parts by weight: PETG resin 50 parts to 80 parts; PBAT resin 10 parts to 40 parts; Calcium carbonate 30 parts to 80 parts; Modified fly ash 10 parts to 30 parts; Coupling agent 0.5 parts to 3 parts; Compatibilizer 1 part to 5 parts; Transesterification inhibitor 0.5 parts to 3 parts.

2. The low warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that The melt index of the PETG resin is 2 g / 10min to 5g / 10min under the test conditions of 250 °C and 2.16 kg; the content of 1,4-cyclohexanedimethanol in the PETG resin is 20wt% to 45 wt%.

3. The low warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that, The melt index of the PBAT resin is 4 g / 10min to 6g / 10min under the test conditions of 190 °C and 2.16 kg.

4. The low-warpage heat-resistant PETG / PBAT composition according to claim 1, wherein The particle size of the calcium carbonate is 200 - 1500 mesh.

5. The low warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that, The modified fly ash is prepared by surface coating modification of first-class ash through chemical activation.

6. The low warpage heat-resistant PETG / PBAT composition according to claim 1, wherein The coupling agent is at least one of titanate coupling agent and aluminate coupling agent.

7. The low-warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that, The compatibilizer is at least one of PE-g-MAH, PP-g-MAH, ethylene-acrylate glycidyl methacrylate, SEBS-g-MAH, and POE-g-GMA.

8. The low-warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that, The transesterification inhibitor is at least one of triphenyl phosphite, sodium dihydrogen phosphate or disodium dihydrogen pyrophosphate.

9. The low-warpage heat-resistant PETG / PBAT composition according to claim 1, characterized in that The raw materials of the composition further include 0.1 part to 2 parts of antioxidant and / or 0.1 part to 2 parts of lubricant.

10. A method for preparing the low-warpage heat-resistant PETG / PBAT composition according to any one of claims 1 to 9, characterized in that, Including: Drying the PETG resin, PBAT resin, calcium carbonate and fly ash; Subjecting the dried fly ash to surface coating modification through chemical activation to obtain modified fly ash; Mixing the dried PETG resin, PBAT resin, calcium carbonate and modified fly ash with the reaction aids evenly in proportion to obtain a mixture; Melting, blending and extruding the above mixture to obtain a PETG / PBAT composition.

11. The preparation method of the low-warpage heat-resistant PETG / PBAT composition according to claim 10, characterized in that The PETG resin and PBAT resin are dried at a temperature of 60 °C to 80 °C for 6 h to 12 h; And / or, the calcium carbonate and fly ash are dried by a high-speed mixer at 80 °C to 130 °C for 1 h to 2 h.

12. The preparation method of the low-warpage heat-resistant PETG / PBAT composition according to claim 10, wherein, The step of subjecting the dried fly ash to surface coating modification through chemical activation to obtain modified fly ash includes: Placing the fly ash and calcium hydroxide solution in an open reaction kettle, fully stirring to make the slurry evenly mixed, heating to 60 °C to 95 °C, and keeping warm for 2 h to 3 h; Introducing carbon dioxide gas until the reaction ends when pH = 7, filtering and drying the reaction slurry to obtain the modified fly ash.

13. The preparation method of the low-warpage heat-resistant PETG / PBAT composition according to claim 12, characterized in that The mass ratio of the fly ash to the calcium hydroxide solution is 1:10, and the concentration of the calcium hydroxide solution is 7wt%; And / or, the rate of introducing carbon dioxide gas is 0.15L / min.

14. The preparation method of the low-warpage heat-resistant PETG / PBAT composition according to claim 10, wherein The mixture is melted, blended and extruded by a twin-screw extruder; The blending temperature is 80°C to 120°C, the mixing time is 10 min to 30 min, and the rotation speed is 300 r / min to 400 r / min; There are 12 temperature setting zones in the twin-screw extruder, which are in turn: the feeding section of zones 1 to 3, with continuous feeding, and the temperature is set at 150°C to 190°C; the melting section of zones 4 to 5, which heats the whole material to form a molten state, and the temperature is set at 180°C to 190°C; the plasticizing section of zones 6 to 7, which plasticizes the material, and the temperature is set at 190°C to 205°C; the exhaust section of zone 8, which discharges the excess pores in the melt, and the temperature is set at 190°C to 205°C; the mixing section of zones 9 to 10, which fully mixes the raw materials, and the temperature is set at 190°C to 205°C; the extrusion section of zones 11 to 12, after the material inside the twin-screw extrusion equipment is extruded, the temperature is set at 190°C to 200°C.

15. Application of the low-warpage heat-resistant PETG / PBAT composition according to any one of claims 1 to 9 in wall panels, indoor floors, outdoor floors, and household countertops.