A high-temperature resistant and biodegradable material for aviation tableware and its preparation method

Abstract

The present invention relates to a high-temperature resistant and biodegradable material for aviation tableware and a preparation method thereof. The high-temperature resistant and biodegradable material for aviation tableware has a heat distortion temperature (0.45 MPa) of 100 - 130 °C, a melting point of 145 - 160 °C, a melt index (190 °C / 2.16 kg) of 4 - 8 g / 10 min, an end carboxyl group content of 8 - 22 mmol / kg, a tensile strength > 35 MPa, an elongation at break > 300%, a flexural strength > 35 MPa, a flexural modulus > 500 MPa, and a relative biodegradation rate in an industrial composting environment for 90 days > 90%. The high-temperature resistant and biodegradable material for aviation tableware has a high melting point and a high softening point, which can meet the high-temperature resistance requirements for microwave heating of tableware in the rail transit and aviation fields. At the same time, the material has high strength and good mechanical properties, and has important application prospects in the fields of aviation straws, table forks, boxes, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of degradable materials, and relates to a high-temperature resistant biodegradable material for aviation tableware and a preparation method thereof. Background Art

[0002] As the main means for treating existing white pollution, biodegradable materials are currently an industry that the country focuses on developing. Traditional non-biodegradable polymer materials such as polypropylene (PP) and polyester (PET) are still used in existing aviation tableware. However, traditional polylactic acid (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) cannot meet the heating temperature resistance requirements of existing aviation tableware due to their low softening temperature and low melting point, resulting in the inability to use existing tableware that needs to be heated in a microwave oven and has a high temperature for serving meals, which brings troubles to the low-carbon and environmental protection development of the aviation industry.

[0003] Based on the method for improving the heat resistance stability of materials, by introducing rigid structures such as benzene rings and polycyclic rings in the molecular structure design, the heat resistance stability is improved. However, inevitably, due to the introduction of rigid structures, especially benzene ring structures, the biodegradable characteristics are damaged; the blending processing technology is the most commonly used modification method for polymer materials. Based on the alloy toughening technology, Zhao Mengmeng et al. improved the compatibility of the polylactic acid and polycarbonate alloy by using a reactive comb-shaped molecular solubilizer, and improved the impact resistance and high-temperature resistance characteristics of polylactic acid. However, polycarbonate itself is a non-biodegradable polymer structure, thus affecting its biodegradable characteristics; therefore, in order not to change the biodegradable characteristics of the material, Seiko Group of Japan used degradable polyvinyl alcohol as the resin material, and introduced it into the polylactic acid matrix through the crosslinkable characteristics of polyvinyl alcohol to improve the mechanical properties and heat resistance of polylactic acid. At the same time, since polyvinyl alcohol itself has biodegradable properties, the impact on its biodegradable characteristics is less, but there is also a problem that aldehydes and other toxic substances need to be used for the crosslinking of polyvinyl alcohol, and the residue in the matrix is difficult to meet the food-grade requirements.

[0004] The project aims at the problems that existing aviation tableware is difficult to biodegrade and conventional biodegradable materials are difficult to meet the high-temperature resistance requirements. By using ultraviolet-cured crosslinked materials, ultraviolet light is used to initiate the curing crosslinking of PLA and PBAT to achieve the improvement of the softening point of the material, and develop a high-temperature resistant biodegradable material that can be heated in a microwave oven, which is of great significance for solving the problem of biodegradable materials for high-temperature resistant aviation tableware in China. Summary of the Invention

[0005] To overcome the deficiencies of the existing technical solutions, the present invention provides a high-temperature resistant and biodegradable material for aviation tableware and a preparation method thereof. The present invention reacts L-serine with biodegradable 1,4-butanediol, which has biodegradable characteristics, to obtain a biodegradable chain extender with four reactive functional groups. The biodegradable chain extender is used to carry out solid-phase polycondensation reaction with polybutylene succinate to prepare a star-shaped high-temperature resistant polybutylene succinate with multiple branches, avoiding the problems that conventional isocyanate chain extenders have biological toxicity and are difficult to degrade, while traditional anhydride and epoxy chain extenders are difficult to biodegrade. At the same time, the molecular weight increases with a binary functional group structure, but the heat resistance performance improvement is limited. After multi-functional group chain extension, excessive cross-linking leads to deterioration of mechanical properties and processing performance, and it is difficult to meet the melting processing conditions. The high-temperature resistant and biodegradable material for aviation tableware has a high melting point and a high softening point, which can meet the high-temperature resistance requirements for microwave heating of tableware in the rail transit and aviation fields. At the same time, the material has high strength and good mechanical properties, and has important application prospects in the fields of aviation straws, forks, boxes, etc.

[0006] To achieve the above object, the following scheme is adopted in the present invention:

[0007] A high-temperature resistant and biodegradable material for aviation tableware has a heat distortion temperature of 100-130 °C under the condition of 0.45 MPa, an end carboxyl group content of 8-22 mmol / kg, and a relative biodegradation rate > 90% in an industrial composting environment for 90 days.

[0008] A high-temperature resistant and biodegradable material for aviation tableware has a melting point of 145-160 °C and a melt index of 4-8 g / 10 min under the condition of 190 °C / 2.16 kg.

[0009] A high-temperature resistant and biodegradable material for aviation tableware has a tensile strength > 35 MPa, an elongation at break > 300%, a flexural strength > 35 MPa, and a flexural modulus > 500 MPa.

[0010] A preparation method of a high-temperature resistant and biodegradable material for aviation tableware, the technical steps thereof include

[0011] (1) Preparation of a biodegradable chain extender

[0012] Using L-serine and 1,4-butanediol as raw materials, putting them into a reaction kettle, carrying out an esterification reaction in a nitrogen atmosphere, controlling the water yield of the esterification reaction to be more than 99%, and then removing the excessive 1,4-butanediol by vacuum distillation to prepare a biodegradable chain extender.

[0013] In step (1), the molar ratio of L-serine to 1,4-butanediol is 1:1.05-1.25;

[0014] In step (1), the temperature of the esterification reaction is 165 - 205 °C.

[0015] (2) Preparation of the viscosity - increasing chips

[0016] Using a biodegradable chain extender and poly(butylene succinate) as raw materials, by means of melt blending, melt extrusion granulation is carried out at 140 - 160 °C to prepare the viscosity - increasing chips.

[0017] In step (2), the terminal carboxyl group of poly(butylene succinate) is 25 - 35 mmol / kg, and the melt index is 4 - 15 g / 10 min.

[0018] In step (2), the mass fraction of the chain extender in the viscosity - increasing chips is 0.5 - 5.0 wt%.

[0019] (3) Preparation of the high - temperature - resistant biodegradable material for aviation tableware

[0020] First, the viscosity - increasing chips are dried at 105 °C for 48 h, and the moisture content of the viscosity - increasing chips is controlled to be below 0.1 wt% to prepare the dried viscosity - increasing chips. Then, by means of solid - state polycondensation, the dried viscosity - increasing chips are subjected to chain - extension and viscosity - increase in a solid - state viscosity - increasing reaction tower to prepare the required high - temperature - resistant biodegradable material for aviation tableware.

[0021] In step (3), the solid - state viscosity - increasing process includes a low - temperature viscosity - increasing reaction, a medium - temperature viscosity - increasing reaction, a high - temperature viscosity - increasing reaction, and a negative - pressure viscosity - increasing reaction;

[0022] The temperature of the low - temperature viscosity - increasing reaction is 105 - 110 °C, and the time of the low - temperature viscosity - increasing reaction is 30 - 120 min;

[0023] The temperature of the medium - temperature viscosity - increasing reaction is 120 - 125 °C, and the time of the medium - temperature viscosity - increasing reaction is 2 - 5 h;

[0024] The temperature of the high - temperature viscosity - increasing reaction is 130 - 140 °C, and the time of the high - temperature viscosity - increasing reaction is 4 - 8 h;

[0025] For the negative - pressure viscosity - increasing reaction, the temperature of the negative - pressure viscosity - increasing reaction is 130 - 135 °C, the vacuum degree of the negative - pressure viscosity - increasing reaction is 1000 - 5000 Pa, and the time of the negative - pressure viscosity - increasing reaction is 30 - 45 min.

[0026] Advantages of the present invention:

[0027] (1) A high-temperature resistant and biodegradable material for aviation tableware and its preparation method according to the present invention. Aiming at the problem that the existing aviation tableware materials, especially the biodegradable materials based on PBS, PBAT, and PLA, have relatively low softening points and are difficult to withstand high-temperature steam and microwave heating environments of 105 - 120 °C. And the conventional cross-linked structure leads to poor processing characteristics of the material, such as the melt index in fluidity and mechanical properties, resulting in poor toughness and difficulty in meeting the processing and use requirements. At the same time, the multi-functional group cross-linked structure makes it difficult to biodegrade, affecting the biodegradable characteristics. By introducing a biodegradable chain extender structure, especially the amino acid structure required by organisms, into the matrix, on the basis of ensuring the performance required for cross-linking, the demand for biodegradable characteristics is also met; and by using a tetra-functional group structure, a star-shaped structure is given during the reaction process, thus avoiding the problem of embrittlement of mechanical properties caused by excessive cross-linking and ensuring the rheological characteristics during the processing process.

[0028] (2) A high-temperature resistant and biodegradable material for aviation tableware and its preparation method according to the present invention. Through a solid-phase viscosity-increasing process, a biodegradable chain extender with a tetra-functional group is used to carry out solid-phase polycondensation reaction with polybutylene succinate to prepare a star-shaped high-temperature resistant polybutylene succinate with multiple branches, avoiding the problems that conventional isocyanate-based chain extenders have biological toxicity and are difficult to degrade, while traditional anhydride and epoxy-based chain extenders are difficult to biodegrade. At the same time, although the molecular weight increases with the binary functional group structure, the improvement of heat resistance is limited, and the mechanical properties and processing properties deteriorate due to excessive cross-linking after multi-functional group chain extension, making it difficult to meet the melt processing conditions, etc.; at the same time, by adopting a process of distributed temperature rise and distributed negative pressure during the solid-phase viscosity-increasing process, the adhesion deformation of the viscosity-increasing chips is avoided by using the distributed temperature, and the small molecules and oligomers can be taken away better and faster by using the negative pressure, thereby further increasing the molecular weight and achieving the purpose of further viscosity increase.

[0029] (3) The high-temperature resistant and biodegradable material for aviation tableware has a high melting point and high softening point, which can meet the high-temperature resistance requirements for microwave heating of tableware in the rail transit and aviation fields. At the same time, the material has high strength and good mechanical properties, and has important application prospects in the fields of aviation straws, forks, boxes, etc. Description of the Drawings

[0030] Figure 1 It is the chemical reaction equation of the biodegradable chain extender of this application;

[0031] Figure 2 It is the NMR spectrum of the biodegradable chain extender of this application;

[0032] Figure 3 It is the structural schematic diagram of the high-temperature resistant and biodegradable material for aviation tableware of this application;

[0033] Figure 4 The nuclear magnetic spectrum of the high-temperature resistant and biodegradable material for aviation tableware of the present application. Specific embodiments

[0034] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0035] The test methods for the parameters in the present invention are as follows:

[0036] (1) Heat distortion temperature: Tested using an XRW-300 series heat distortion temperature tester according to the method specified in the national standard GB / T1634.1-2019;

[0037] (2) Melting point: Measured using a Q20 differential scanning calorimeter, with nitrogen as the protective gas, a gas flow rate of 50 mL / min, and a heating rate of 10 °C / min. The maximum melting peak during the heating process is the melting point;

[0038] (3) Melt index: Tested using a Kunshan Hongjin HJ-RRZS melt index tester according to the method of standard ASTM D 1238;

[0039] (4) Terminal carboxyl group content: Tested using a burette, with phenol and chloroform as solvents, and the volume ratio of the phenol and chloroform solution being 2:3, referring to the national standard GB / T 14190-2017;

[0040] (5) Mechanical properties (tensile strength, elongation at break, flexural strength, flexural modulus): Tested using a Shimadzu AUX-5000 universal testing machine according to the method of the national standard GB1040-2018;

[0041] (6) Biodegradation rate: Tested using a Biop's biodegradation test system according to the method of the national standard GB / T19277.1-2011.

[0042] Example 1

[0043] A high-temperature resistant and biodegradable material for aviation tableware and its preparation method. The high-temperature resistant and biodegradable material for aviation tableware has a heat distortion temperature (0.45 MPa) of 100 °C, a melting point of 145 °C, a melt index (190 °C / 2.16 kg) of 8 g / 10 min, an end carboxyl group content of 22 mmol / kg, a tensile strength of 35.5 MPa, an elongation at break of 350%, a flexural strength of 35.9 MPa, a flexural modulus of 510 MPa, and a relative biodegradation rate of 96% in an industrial composting environment for 90 days.

[0044] The preparation method of the high-temperature resistant and biodegradable material for aviation tableware as described above comprises the following steps:

[0045] (1) Preparation of a biodegradable chain extender

[0046] Using L-serine and 1,4-butanediol as raw materials, putting them into a reaction kettle, carrying out an esterification reaction in a nitrogen atmosphere, controlling the water yield of the esterification reaction to be above 99%, and then removing the excessive 1,4-butanediol by vacuum distillation to prepare the biodegradable chain extender.

[0047] The molar ratio of the L-serine to the 1,4-butanediol is 1:1.25, and the temperature of the esterification reaction is 165 °C.

[0048] (2) Preparation of a viscosity-increasing chip

[0049] Using the biodegradable chain extender and polybutylene succinate as raw materials, adopting a melt blending method, melt extruding and pelletizing at 140 °C to prepare the viscosity-increasing chip.

[0050] The end carboxyl group of the polybutylene succinate is 35 mmol / kg, and the melt index is 15 g / 10 min.

[0051] The mass fraction of the chain extender in the viscosity-increasing chip is 0.5 wt%.

[0052] (3) Preparation of the high-temperature resistant and biodegradable material for aviation tableware

[0053] First, the viscosity-increasing chip is dried at 105 °C for 48 h, and the water content of the viscosity-increasing chip is controlled to be below 0.1 wt% to prepare the dried viscosity-increasing chip. Then, adopting a solid-phase polycondensation method, the dried viscosity-increasing chip is subjected to chain extension and viscosity increase in a solid-phase viscosity-increasing reaction tower to prepare the required high-temperature resistant and biodegradable material for aviation tableware.

[0054] The solid-phase viscosity-increasing process described above includes low-temperature viscosity-increasing reaction, medium-temperature viscosity-increasing reaction, high-temperature viscosity-increasing reaction, and negative-pressure viscosity-increasing reaction; the temperature of the low-temperature viscosity-increasing reaction is 105°C, and the time of the low-temperature viscosity-increasing reaction is 120 min; the temperature of the medium-temperature viscosity-increasing reaction is 120°C, and the time of the medium-temperature viscosity-increasing reaction is 5 h; the temperature of the high-temperature viscosity-increasing reaction is 130°C, and the time of the high-temperature viscosity-increasing reaction is 8 h; for the negative-pressure viscosity-increasing reaction, the temperature is 130°C, the vacuum degree of the negative-pressure viscosity-increasing reaction is 1000 Pa, and the time of the negative-pressure viscosity-increasing reaction is 45 min.

[0055] Example 2

[0056] For a high-temperature resistant and biodegradable material for aviation tableware and its preparation method in this application, the heat distortion temperature (0.45 MPa) of the high-temperature resistant and biodegradable material for aviation tableware is 130°C, the melting point is 160°C, the melt index (190°C / 2.16 kg) is 8 g / 10 min, the terminal carboxyl group content is 8 mmol / kg, the tensile strength is 36 MPa, the elongation at break is 350%, the flexural strength is 37.8 MPa, the flexural modulus is 550 MPa, and its relative biodegradation rate in an industrial composting environment for 90 days is 95%.

[0057] The preparation method of the high-temperature resistant and biodegradable material for aviation tableware as described above includes the following steps:

[0058] (1) Preparation of a biodegradable chain extender

[0059] Using L-serine and 1,4-butanediol as raw materials, put them into a reaction kettle, carry out an esterification reaction in a nitrogen atmosphere, control the water yield of the esterification reaction to be more than 99%, and then remove the excessive 1,4-butanediol by vacuum distillation to prepare a biodegradable chain extender.

[0060] The molar ratio of the L-serine to the 1,4-butanediol is 1:1.05, and the temperature of the esterification reaction is 205°C.

[0061] (2) Preparation of viscosity-increasing chips

[0062] Using the biodegradable chain extender and polybutylene succinate as raw materials, adopt the method of melt blending, and carry out melt extrusion granulation at 160°C to prepare viscosity-increasing chips.

[0063] The terminal carboxyl group of the polybutylene succinate is 25 mmol / kg, and the melt index is 4 g / 10 min.

[0064] The mass fraction of the chain extender in the viscosity-increasing chips is 5.0 wt%.

[0065] (3) Preparation of a high-temperature resistant and biodegradable material for aviation tableware

[0066] First, the tackified chips are dried at 105 °C for 48 h, and the moisture content of the tackified chips is controlled to be below 0.1 wt%, to obtain dried tackified chips. Then, by the method of solid-phase polycondensation, the dried tackified chips are subjected to chain extension and tackification in a solid-phase tackification reaction tower, to obtain the required high-temperature resistant biodegradable material for aviation tableware.

[0067] The solid-phase tackification process includes low-temperature tackification reaction, medium-temperature tackification reaction, high-temperature tackification reaction and negative-pressure tackification reaction; the temperature of the low-temperature tackification reaction is 110 °C, and the time of the low-temperature tackification reaction is 120 min; the temperature of the medium-temperature tackification reaction is 125 °C, and the time of the medium-temperature tackification reaction is 2 h; the temperature of the high-temperature tackification reaction is 140 °C, and the time of the high-temperature tackification reaction is 4 h; the negative-pressure tackification reaction is that the temperature of the negative-pressure tackification reaction is 135 °C, the vacuum degree of the negative-pressure tackification reaction is 5000 Pa, and the time of the negative-pressure tackification reaction is 30 min.

[0068] Example 3

[0069] For a high-temperature resistant biodegradable material for aviation tableware and its preparation method in this application, the heat distortion temperature (0.45 MPa) of the high-temperature resistant biodegradable material for aviation tableware is 130 °C, the melting point is 155 °C, the melt index (190 °C / 2.16 kg) is 5 g / 10 min, the terminal carboxyl group content is 10 mmol / kg, the tensile strength is 37.4 MPa, the elongation at break is 450%, the flexural strength is 39.2 MPa, the flexural modulus is 6500 MPa, and its relative biodegradation rate in an industrial composting environment for 90 days is 95%.

[0070] The preparation method of the high-temperature resistant biodegradable material for aviation tableware as described above includes the following steps:

[0071] (1) Preparation of a biodegradable chain extender

[0072] Using L-serine and 1,4-butanediol as raw materials, put them into a reaction kettle, carry out an esterification reaction in a nitrogen atmosphere, control the water yield of the esterification reaction to be above 99%, and then through vacuum distillation, remove the excessive 1,4-butanediol, to obtain a biodegradable chain extender.

[0073] The molar ratio of the L-serine to the 1,4-butanediol is 1:1.15, and the temperature of the esterification reaction is 195 °C.

[0074] (2) Preparation of tackified chips

[0075] Using the biodegradable chain extender and polybutylene succinate as raw materials, by the method of melt blending, melt extrusion and pelletization are carried out at 150 °C, to obtain tackified chips.

[0076] The terminal carboxyl group of the polybutylene succinate is 26 mmol / kg, and the melt index is 8 g / 10 min.

[0077] The mass fraction of the chain extender in the viscosity-increased chips is 4.0 wt%.

[0078] (3) Preparation of high-temperature resistant biodegradable material for aviation tableware

[0079] First, the viscosity-increased chips are dried at 105 °C for 48 h, and the moisture content of the viscosity-increased chips is controlled to be below 0.1 wt% to obtain dried viscosity-increased chips. Then, by the method of solid-phase polycondensation, the dried viscosity-increased chips are subjected to chain extension and viscosity increase in a solid-phase viscosity increase reaction tower to obtain the required high-temperature resistant biodegradable material for aviation tableware.

[0080] The solid-phase viscosity increase process includes low-temperature viscosity increase reaction, medium-temperature viscosity increase reaction, high-temperature viscosity increase reaction, and negative-pressure viscosity increase reaction; the temperature of the low-temperature viscosity increase reaction is 110 °C, and the time of the low-temperature viscosity increase reaction is 120 min; the temperature of the medium-temperature viscosity increase reaction is 125 °C, and the time of the medium-temperature viscosity increase reaction is 5 h; the temperature of the high-temperature viscosity increase reaction is 140 °C, and the time of the high-temperature viscosity increase reaction is 8 h; the negative-pressure viscosity increase reaction is that the temperature of the negative-pressure viscosity increase reaction is 135 °C, the vacuum degree of the negative-pressure viscosity increase reaction is 1000 Pa, and the time of the negative-pressure viscosity increase reaction is 45 min.

[0081] Figure 1 It is the chemical reaction equation for the preparation of the biodegradable chain extender. Figure 2 It is the 1H NMR spectrum of the biodegradable chain extender. The chemical shift structures corresponding to a (4.20 - 4.28 ppm) and b (3.98 - 4.08 ppm) are the characteristic peaks of ethyl groups. c (3.51 - 3.55 ppm) is the characteristic peak of the hydroxyl group structure or electron-withdrawing group. At the same time, d (1.99 - 2.02 ppm) is the characteristic peak of the hydroxyl group structure or amino group structure, and e (1.48 - 1.57 ppm) is the ethyl functional group in the alkane. The characteristic peak of carboxylic acid disappears in the spectrum, while there are a large number of characteristic peaks of hydroxyl group structures in the spectrum, indicating that L-serine and 1,4-butanediol have reacted. At the same time, the unique ethyl functional group e in the 1,4-butanediol framework is observed in the spectrum, and a multiple splitting peak structure appears in the functional group, so it is also confirmed that L-serine and 1,4-butanediol have reacted. At the same time, through the analysis of the peak area ratio of the characteristic peaks a, b, and e, the ratio of the sum of the peak areas Sab of a and b to the peak area Se of e, Sab:Se, is 1:1.01. Therefore, it shows that L-serine and 1,4-butanediol have reacted in a 1:1 ratio, indicating that the synthesized compound is the required biodegradable chain extender.

[0082] Figure 3 It is the molecular structure schematic diagram of the high-temperature resistant biodegradable material for aviation tableware.Figure 4 The NMR spectrum of the high-temperature resistant and biodegradable material for aviation tableware. The characteristic absorption peak corresponding to 2.64 ppm is the ethyl structure on succinic acid in PBS. At the same time, the characteristic peak of the hydrogen NMR spectrum unique to the biodegradable chain extender in the spectrum is at 5.02 ppm, corresponding to the characteristic peak structure of the α-H structure connected to the carbonyl group (C=O) and amino group in the biodegradable chain extender. At the same time, the amino characteristic peak in the structure of the biodegradable chain extender is not found in the spectrum. Therefore, it shows that the biodegradable chain extender has undergone a chain extension reaction with polybutylene succinate (PBS), and at the same time, the amino groups (-NH2) on the original chain extender have all undergone chain extension reactions, and the corresponding biodegradable chain extender reacts with PBS to form a star structure. By comparing the characteristic peak area S1 at 2.64 ppm and the characteristic peak area S2 at 5.02 ppm, the ratio of S2:S1 is obtained as 1:101. Since the ethyl group corresponds to 4 hydrogens and the chain extender corresponds to 1 hydrogen, and the addition amount of the chain extender is 4.0%, it shows that theoretically the ratio of S2:S1 is 1:100. Therefore, it is close to the obtained peak area, indicating that the chain extender reacts with PBS to form a material with a star structure, which is the designed Figure 3 Molecular structure of the high-temperature resistant and biodegradable material for aviation tableware.

[0083] Example 4

[0084] A high-temperature resistant and biodegradable material for aviation tableware and its preparation method in this application. The heat distortion temperature (0.45 MPa) of the high-temperature resistant and biodegradable material for aviation tableware is 120 °C, the melting point is 150 °C, the melt index (190 °C / 2.16 kg) is 6 g / 10 min, the end carboxyl group content is 18 mmol / kg, the tensile strength is 36.2 MPa, the elongation at break is 380%, the flexural strength is 35.9 MPa, the flexural modulus is 550 MPa, and its relative biodegradation rate in the industrial composting environment for 90 days is 96%.

[0085] The preparation method of the high-temperature resistant and biodegradable material for aviation tableware as described above includes the following steps:

[0086] (1) Preparation of the biodegradable chain extender

[0087] Using L-serine and 1,4-butanediol as raw materials, put them into a reaction kettle, carry out an esterification reaction in a nitrogen atmosphere, control the water yield of the esterification reaction to be more than 99%, and then remove the excess 1,4-butanediol by vacuum distillation to prepare the biodegradable chain extender.

[0088] The molar ratio of the L-serine and 1,4-butanediol is 1:1.20, and the temperature of the esterification reaction is 200 °C.

[0089] (2) Preparation of the viscosity-increasing chips

[0090] Using a biodegradable chain extender and polybutylene succinate as raw materials, by means of melt blending, melt extrusion granulation is carried out at 160 °C to prepare a viscosity-increasing chip.

[0091] The terminal carboxyl group of the polybutylene succinate is 35 mmol / kg, and the melt index is 15 g / 10 min.

[0092] The mass fraction of the chain extender in the viscosity-increasing chip is 5.0 wt%.

[0093] (3) Preparation of a high-temperature resistant biodegradable material for aviation tableware

[0094] First, the viscosity-increasing chip is dried at 105 °C for 48 h, and the moisture content of the viscosity-increasing chip is controlled to be below 0.1 wt% to prepare a dried viscosity-increasing chip. Then, by means of solid-phase polycondensation, the dried viscosity-increasing chip is subjected to chain extension and viscosity increase in a solid-phase viscosity-increasing reaction tower to prepare the required high-temperature resistant biodegradable material for aviation tableware.

[0095] The solid-phase viscosity-increasing process includes a low-temperature viscosity-increasing reaction, a medium-temperature viscosity-increasing reaction, a high-temperature viscosity-increasing reaction, and a negative-pressure viscosity-increasing reaction; the temperature of the low-temperature viscosity-increasing reaction is 110 °C, and the time of the low-temperature viscosity-increasing reaction is 90 min; the temperature of the medium-temperature viscosity-increasing reaction is 120 °C, and the time of the medium-temperature viscosity-increasing reaction is 5 h; the temperature of the high-temperature viscosity-increasing reaction is 135 °C, and the time of the high-temperature viscosity-increasing reaction is 6 h; the negative-pressure viscosity-increasing reaction is that the temperature of the negative-pressure viscosity-increasing reaction is 135 °C, the vacuum degree of the negative-pressure viscosity-increasing reaction is 1000 Pa, and the time of the negative-pressure viscosity-increasing reaction is 45 min.

[0096] Example 5

[0097] For a high-temperature resistant biodegradable material for aviation tableware and its preparation method in this application, the heat distortion temperature (0.45 MPa) of the high-temperature resistant biodegradable material for aviation tableware is 125 °C, the melting point is 160 °C, the melt index (190 °C / 2.16 kg) is 5 g / 10 min, the terminal carboxyl group content is 12 mmol / kg, the tensile strength is 35.9 MPa, the elongation at break is 360%, the flexural strength is 37.0 MPa, the flexural modulus is 540 MPa, and its relative biodegradation rate in an industrial composting environment for 90 days is 95%.

[0098] The preparation method of the high-temperature resistant biodegradable material for aviation tableware as described above includes the following steps:

[0099] (1) Preparation of a biodegradable chain extender

[0100] Using L-serine and 1,4-butanediol as raw materials, put them into a reaction kettle, carry out an esterification reaction in a nitrogen atmosphere, control the water yield of the esterification reaction to be more than 99%, and then remove the excessive 1,4-butanediol by vacuum distillation to prepare a biodegradable chain extender.

[0101] The molar ratio of the L-serine to the 1,4-butanediol is 1:1.15, and the temperature of the esterification reaction is 200 °C.

[0102] (2) Preparation of the viscosity-increasing chips

[0103] Using the biodegradable chain extender and poly(butylene succinate) as raw materials, by means of melt blending, melt extrusion and pelletization are carried out at 160 °C to prepare the viscosity-increasing chips.

[0104] The terminal carboxyl group of the poly(butylene succinate) is 28 mmol / kg, and the melt index is 12 g / 10 min.

[0105] The mass fraction of the chain extender in the viscosity-increasing chips is 4.5 wt%.

[0106] (3) Preparation of the high-temperature resistant biodegradable material for aviation tableware

[0107] First, the viscosity-increasing chips are dried at 105 °C for 48 h, and the water content of the viscosity-increasing chips is controlled to be below 0.1 wt% to prepare the dried viscosity-increasing chips. Then, by means of solid-state polycondensation, the dried viscosity-increasing chips are subjected to chain extension and viscosity increase in a solid-state viscosity-increasing reaction tower to prepare the required high-temperature resistant biodegradable material for aviation tableware.

[0108] The solid-state viscosity-increasing process includes a low-temperature viscosity-increasing reaction, a medium-temperature viscosity-increasing reaction, a high-temperature viscosity-increasing reaction and a negative-pressure viscosity-increasing reaction; the temperature of the low-temperature viscosity-increasing reaction is 110 °C, and the time of the low-temperature viscosity-increasing reaction is 90 min; the temperature of the medium-temperature viscosity-increasing reaction is 125 °C, and the temperature of the medium-temperature viscosity-increasing reaction is 5 h; the temperature of the high-temperature viscosity-increasing reaction is 140 °C, and the time of the high-temperature viscosity-increasing reaction is 6 h; the negative-pressure viscosity-increasing reaction is that the temperature of the negative-pressure viscosity-increasing reaction is 135 °C, the vacuum degree of the negative-pressure viscosity-increasing reaction is 1000 Pa, and the time of the negative-pressure viscosity-increasing reaction is 45 min.

[0109] Comparative Example 1

[0110] Basically the same as Example 3, the difference is that in step (1), L-serine is directly used as the structure of the chain extender.

[0111] Since the chain extender contains a carboxylic acid structure in its molecular structure, during the melt extrusion and processing, the PBS chips are severely decomposed in an acidic high-temperature environment, resulting in difficulty in obtaining the viscosity-increasing chips.

[0112] Comparative Example 2

[0113] Basically the same as Example 3, the only difference being that in step (1), butanediol is replaced with butanol.

[0114] In the tackifying slice and the material described, the mechanical properties of the material are 22.5 MPa, the heat distortion temperature is 105 °C, and the biodegradability performance in the biodegradability test is 56%. Since butanol is easily removed during the preparation process, it is extremely easy to become inactivated during the tackifying process, resulting in obstruction of the PBS tackifying process. At the same time, the structure of unreacted butanol itself is not biodegradable, and there are differences in the alcohol structure between the material and the PBS matrix, so it will affect its biodegradability performance.

[0115] Comparative Example 3

[0116] Basically the same as Example 3, the difference being that in step (3), vacuum negative pressure tackifying reaction is not used; the obtained material has a heat distortion temperature of 80 °C, a melt index of 10 g / 10 min, an end carboxyl group content of 20 mmol / kg, a tensile strength of 25 MPa, an elongation at break of 300%, a flexural strength of 20 MPa, and a flexural modulus of 400 MPa. Its relative biodegradation rate in the industrial composting environment for 90 days is 95%. Although the material has certain mechanical properties, due to the lack of the vacuum negative pressure tackifying process, there are more oligomers inside, resulting in limited increase in the heat distortion temperature of the material. And due to the influence of the internal oligomers, the mechanical properties of the material are not ideal and have a relatively serious reduction.

[0117] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A high-temperature resistant and biodegradable material for aviation tableware, characterized in that, The heat distortion temperature is 100 - 130 °C under the condition of 0.45 MPa, the terminal carboxyl content is 8 - 22 mmol / kg, and the relative biodegradation rate in the industrial composting environment for 90 days > 90%; The preparation method of the high-temperature resistant biodegradable material for aviation tableware described above includes the following technical steps: (1) Preparation of the biodegradable chain extender Using L-serine and 1,4-butanediol as raw materials, put them into a reaction kettle, carry out an esterification reaction in a nitrogen atmosphere, control the water yield of the esterification reaction to be more than 99%, and then remove the excessive 1,4-butanediol by vacuum distillation to prepare the biodegradable chain extender; (2) Preparation of the viscosity-increasing chips Using the biodegradable chain extender and polybutylene succinate as raw materials, adopt the method of melt blending, and carry out melt extrusion granulation at 140 - 160 °C to prepare the viscosity-increasing chips; (3) Preparation of the high-temperature resistant biodegradable material for aviation tableware First, dry the viscosity-increasing chips at 105 °C for 48 h, control the moisture content of the viscosity-increasing chips to be below 0.1 wt% to prepare the dried viscosity-increasing chips, and then adopt the method of solid-phase polycondensation. The dried viscosity-increasing chips are subjected to chain extension and viscosity increase in a solid-phase viscosity-increasing reaction tower to prepare the required high-temperature resistant biodegradable material for aviation tableware; The solid-phase viscosity-increasing process includes low-temperature viscosity-increasing reaction, medium-temperature viscosity-increasing reaction, high-temperature viscosity-increasing reaction, and negative-pressure viscosity-increasing reaction; The low-temperature viscosity-increasing reaction temperature is 105 - 110 °C, and the low-temperature viscosity-increasing reaction time is 30 - 120 min; The medium-temperature viscosity-increasing reaction temperature is 120 - 125 °C, and the medium-temperature viscosity-increasing reaction time is 2 - 5 h; The high-temperature viscosity-increasing reaction temperature is 130 - 140 °C, and the high-temperature viscosity-increasing reaction time is 4 - 8 h; The negative-pressure viscosity-increasing reaction temperature is 130 - 135 °C, the negative-pressure viscosity-increasing reaction vacuum degree is 1000 - 5000 Pa, and the negative-pressure viscosity-increasing reaction time is 30 - 45 min.

2. The high-temperature resistant and biodegradable material for aviation tableware according to claim 1, wherein The melting point is 145 - 160 °C, and the melt index is 5 - 8 g / 10 min under the condition of 190 °C / 2.16 kg.

3. The high-temperature resistant and biodegradable material for aviation tableware according to claim 1, wherein The tensile strength > 35 MPa, the elongation at break > 300%, the flexural strength > 35 MPa, and the flexural modulus > 500 MPa.

4. A high-temperature resistant and biodegradable material for aviation tableware according to claim 1, characterized in that, In step (1), the molar ratio of L-serine to 1,4-butanediol is 1:1.05 - 1.

25.

5. A high-temperature resistant and biodegradable material for aviation tableware according to claim 1, characterized in that, In step (1), the temperature of the esterification reaction is 165 - 205 °C.

6. The high-temperature resistant and biodegradable material for aviation tableware according to claim 1, wherein In step (2), the terminal carboxyl of polybutylene succinate is 25 - 35 mmol / kg, and the melt index is 4 - 15 g / 10 min.

7. The high-temperature resistant and biodegradable material for aviation tableware according to claim 1, wherein In step (2), the mass fraction of the chain extender in the viscosity-increasing chips is 0.5 - 5.0 wt%.

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