A high-barrier PBCT / PBAT alloy material, its blow molded product and processing method

Abstract

The present invention discloses a rapid preparation method for an alloy material of poly(butylene terephthalate-co-carbonate) (PBCT) and poly(butylene adipate-co-terephthalate) (PBAT), and a series of high-barrier alloy materials with good light transmittance, excellent mechanical properties and easy processability are obtained through single-screw blow molding processing. In this method, PBCT and PBAT are blended without adding any blending compatibilizer, and under the action of the remaining transesterification catalyst in the system during melt polycondensation, rapid reactive compatibility of the two phases can be achieved. By adjusting the molar ratio of the aromatic polyester in PBCT and the component of PBCT in the alloy, precise control of materials with ideal properties can be realized. Through the blending method described in this application, the comprehensive properties of PBAT can be significantly improved, which is of great significance for the development of new packaging materials.

Description

Technical Field

[0001] The present invention belongs to the field of biodegradable biomass, and particularly relates to a reactive compatible high-barrier PBCT / PBAT alloy material, its blow molded product, and processing method. Background Art

[0002] Polymer materials have the characteristics of light weight, insulation, corrosion resistance, wear resistance, easy processing, low price, etc. Coupled with their numerous types and different properties, they are widely used in various aspects from high-precision technologies such as aerospace to civilian products. However, while polymer materials bring great convenience to human life, their non-degradability also causes great pressure on the ecological environment. Developing environmentally friendly degradable plastics has become a key issue that all chemical enterprises urgently need to solve.

[0003] Poly(butylene adipate-co-terephthalate) (PBAT), as a typical aromatic-aliphatic biodegradable polyester, has currently become a very popular key chemical, with a booming production capacity and creating huge market benefits. However, the aliphatic repeating segments in the main chain repeating unit of PBAT are relatively long, so its modulus and strength are relatively low, which limits the application of PBAT in fields such as food packaging and agricultural mulch films. Poly(butylene carbonate-co-terephthalate) (PBCT) is a new type of aromatic-aliphatic polyester. By replacing adipic acid in the main chain structure of PBAT with renewable resource dimethyl carbonate, the aliphatic structure in the main chain repeating unit is reduced. Therefore, compared with PBAT, the strength and modulus of PBCT will be improved to a certain extent. In addition, the relatively high ester group density of PBCT can further optimize the barrier properties of PBAT.

[0004] Compared with copolymer modification, melt blending modification has the advantages of convenience, speed, and adjustable properties. However, during multiphase melt blending, due to the difference in the compatibility of the blend, phase separation is very likely to occur, forming a large number of defect points agglomerated in the matrix, thus reducing rather than increasing the properties of the alloy material. Therefore, an additional blend compatibilizer is usually required during multiphase melt blending to optimize the blend compatibility. However, taking alloy materials such as PBAT / PLA or PBAT / PBST as examples, after adding the blend compatibilizer, their blend compatibility is still poor, with obvious phase separation phenomena, reducing the service performance of the product. How to solve the problem of poor blend compatibility of PBAT alloy materials is of great significance for expanding the industrial application of PBAT. Summary of the Invention

[0005] In view of the above technical problems, the present invention provides a preparation method of a highly barrier PBCT / PBAT alloy material that is reactively compatible with poly(butylene adipate-co-terephthalate) (PBAT). By utilizing the terminal ester groups of poly(butylene carbonate terephthalate) (PBCT) and the terminal hydroxyl groups of PBAT, and under the action of the residual catalyst in melt polycondensation that catalyzes the transesterification reaction, rapid reactive compatibility can be achieved. By regulating the content of aromatic groups in PBCT, the properties of the alloy material can be regulated. The prepared PBCT / PBAT alloy material is blow-molded into a film to obtain a series of degradable blow-molded products with good properties. The present invention can fundamentally solve the disadvantage of poor blend compatibility of PBAT alloy materials, which is of great significance for expanding the industrial application of PBAT.

[0006] One of the purposes of the present invention is to provide a reactively compatible highly barrier PBCT / PBAT alloy material and a rapid preparation method to solve the technical problems such as low strength, low modulus, poor barrier performance of PBAT, and poor blend compatibility of alloy materials mentioned in the above background technology.

[0007] Another purpose of the present invention is to provide a preparation method for blow-molded products of a PBCT / PBAT alloy material with controllable properties.

[0008] To achieve the above purposes, the present invention provides the following technical solutions:

[0009] In the first aspect, the present invention discloses a reactively compatible highly barrier PBCT / PBAT alloy material with the structure shown in the following formula:

[0010]

[0011] Among them, m, n, x, and y are natural numbers, and the value range is 20-300;

[0012] m represents the number of repeating units of the aromatic chain segment (butylene terephthalate chain segment) in PBCT in the main chain of the alloy material; n represents the number of repeating units of the aliphatic chain segment (butylene carbonate chain segment) in PBCT in the main chain of the alloy material; x represents the number of repeating units of the aliphatic chain segment (butylene adipate chain segment) in PBAT in the main chain of the alloy material, and y represents the number of repeating units of the aromatic chain segment (butylene terephthalate chain segment) in PBAT in the main chain of the alloy material.

[0013] Furthermore, the intrinsic viscosity of the highly barrier PBCT / PBAT alloy material is 1.0-2.0 dL / g, the number average molecular weight is 50-100 kg / mol, the glass transition temperature is -30-44 °C, the melting temperature is 117-230 °C, and the melt index is 3.0-20 g / 10 min.

[0014] Furthermore, by weight percentage, the proportion of PBCT in the high-barrier PBCT / PBAT alloy material is 1-99%, and the rest is PBAT.

[0015] Furthermore, by molar percentage, the number of aromatic chain segments in the PBCT accounts for 1-99% of the total number of aliphatic and aromatic chain segments in the PBCT, and the rest is aliphatic chain segments; the number of aromatic chain segments in the PBAT accounts for 47% of the total number of aliphatic and aromatic chain segments in the PBAT, and the rest is aliphatic chain segments.

[0016] Furthermore, by weight percentage, the proportion of PBCT in the high-barrier PBCT / PBAT alloy material is 20-80%.

[0017] Furthermore, by weight percentage, the proportion of PBCT in the high-barrier PBCT / PBAT alloy material is 50-60%.

[0018] Furthermore, the number of aromatic chain segments in the PBCT accounts for 40-60% of the total number of aliphatic and aromatic chain segments in the PBCT, and the rest is aliphatic chain segments.

[0019] Furthermore, the aromatic chain segments in the PBCT account for 49-58% of the total number of aliphatic and aromatic chain segments in the PBCT, and the rest is aliphatic chain segments.

[0020] In a second aspect, a method for preparing a high-barrier PBCT / PBAT alloy material is provided, and the steps are as follows:

[0021] (1) After fully mixing PBCT and PBAT in a certain proportion, a premix is obtained;

[0022] (2) The premix is extruded and pelletized through a twin-screw extruder. The temperature of the twin-screw extruder is 160-260 °C, and the rotation speed is 10-30 Hz; the feeding rotation speed is 1.0-5.0 Hz. The extruded melt is cooled by water, stretched, air-dried and pelletized to obtain the PBCT / PBAT alloy material.

[0023] Furthermore, the obtained PBCT / PBAT alloy material is placed in a vacuum oven at 60 °C and dried for 24 h to remove moisture.

[0024] Furthermore, the mass ratio of PBCT to PBAT is 1:99-99:1.

[0025] Furthermore, the mass ratio of PBCT to PBAT is 1:4-4:1.

[0026] Furthermore, in terms of molar percentage, the number of aromatic segments in the PBCT accounts for 1 to 99% of the total number of aliphatic segments and aromatic segments in the PBCT, and the rest are aliphatic segments.

[0027] Furthermore, in terms of molar percentage, the number of aromatic segments in the PBAT accounts for 47% of the total number of aliphatic segments and aromatic segments in the PBAT, and the rest are aliphatic segments.

[0028] Thirdly, a processing method for a high-barrier PBCT / PBAT alloy material blow-molded product is provided, wherein the dried alloy material is fed into a single-screw melt extrusion film blowing machine, and the feeding section, plasticizing section, and discharge port template temperatures are set to 160-240°C, 170-250°C, and 180-260°C, respectively. During the blow molding process, the main engine speed is 10-30Hz, and the feeding speed is 1.0-5.0Hz; after air cooling and stretching blow molding, the film is formed with a stretch ratio of 20-80, and the final PBCT / PBAT alloy material film thickness is between 10 and 35μm.

[0029] Furthermore, the temperatures of the feeding section, plasticizing section and discharge port template of the single-screw extrusion film blowing machine are 180-240°C, 190-250°C and 200-260°C respectively, the main engine speed is 20Hz, and the feeding speed is 2.0Hz.

[0030] Furthermore, the PBAT in step (1) is KHB21AP11 or KHB21BP11 from China Kanghui New Materials Co., Ltd., or KHB21BP11 from BASF of Germany. At least one of Ecoworld from China Jinhui Zhaolong Company and TH801T from Xinjiang Blue Mountain Tunhe Polyester Co., Ltd., China.

[0031] Beneficial effects:

[0032] The present invention is to use the reactive compatibility mechanism to quickly prepare a PBCT / PBAT alloy material with controllable performance. The aromatic-aliphatic polyester PBCT terminated with an ester group and the aromatic-aliphatic polyester PBAT terminated with a hydroxyl group are directly melt-blended, and a PBCT / PBAT alloy material with perfect compatibility is obtained without adding any blending compatibilizer. Among them: by adjusting the proportion of aromatic segments in PBCT, the strength, toughness, heat resistance and barrier properties of PBAT can be adjusted, thereby achieving the precise synthesis of PBCT / PBAT alloy materials with ideal performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The PBCT / PBAT alloy material obtained in Example 1 of the present invention 1 H-NMR spectrum;

[0034] Figure 2 is the DSC spectrum of the PBCT / PBAT alloy material obtained in Example 1 of the present invention;

[0035] Figure 3 is the blow-molded product of the PBCT / PBAT alloy material obtained in Example 1 of the present invention. Specific Embodiments

[0036] The present invention will be further described below in conjunction with specific embodiments, but the present invention should not be limited to the following embodiments.

[0037] The intrinsic viscosity, molecular weight, thermal properties, melt index, and water barrier properties in the following embodiments were measured according to the following methods:

[0038] Intrinsic viscosity: 0.2 g of the PBCT / PBAT alloy material was dissolved in 20 ml of a mixed solution of phenol-1,1,2,2-tetrachloroethane with a mass ratio of 1:1, and measured in a water bath at 25 °C using the one-point method. The calculation formula for the intrinsic viscosity is:

[0039]

[0040]

[0041]

[0042] Where: η r : relative viscosity, η sp : specific viscosity, t 0 : solvent efflux time, t 1 : polymer solution efflux time, c: polymer solution concentration.

[0043] Molecular weight: Gel Permeation Chromatograph (GPC), using chloroform as the solvent and monodisperse polystyrene as the standard sample;

[0044] Thermal properties: characterized by a Differential Scanning Calorimeter (DSC);

[0045] Melt index: characterized by a melt index tester based on national standards GBT3682.1 and 3682.2;

[0046] Water barrier property: characterized by a water vapor transmission rate tester based on the international standard ISO15106-2:2003.

[0047] Example 1. Rapid preparation of a reactive compatibilized high-barrier PBCT / PBAT alloy material and processing method of a blow-molded product

[0048] (1) 500 g of homemade PBCT with an aromatic content of 58% and 500 g of commercially available PBAT were fully mixed and added to a twin-screw extruder. The processing temperatures from the feed port to the die of the twin-screw extruder were 180° C., 182° C., 185° C., 185° C., 187° C., 190° C. and 180° C., respectively. The main engine speed was 25 Hz, and the feed speed was 4.0 Hz. After water cooling, pelletizing and drying, a PBCT / PBAT alloy material was obtained, wherein: the intrinsic viscosity was 1.35 dL / g, the number average molecular weight was 85.3 kg / mol, the glass transition temperature was -16.5° C., the melting temperature was 133.8° C., and the melt index was 4.3 g / 10 min;

[0049] (2) The dried alloy material was then added to a single-screw extruder film blowing machine, and the feeding section, plasticizing section, and outlet template temperatures were set to 180°C, 190°C, and 192°C, respectively. During the blow molding process, the main engine speed was 20 Hz and the feed speed was 2.0 Hz. After air cooling and stretching blow molding, the stretch ratio was 40, and the final PBCT / PBAT alloy material film thickness was 15-20 μm, and the water vapor permeability coefficient was 5.5×10 -14 g cm / cm 2 ·s·Pa.

[0050] Example 2. Rapid preparation of reactive and compatible high-barrier PBCT / PBAT alloy materials and processing methods for blow-molded products

[0051] (1) 500 g of homemade PBCT with an aromatic content of 49% and 500 g of commercially available PBAT were fully mixed and added to a twin-screw extruder. The processing temperatures from the feed port to the die of the twin-screw extruder were 175° C., 180° C., 182° C., 182° C., 185° C., 190° C. and 180° C., respectively. The main engine speed was 25 Hz, and the feed speed was 4.0 Hz. After water cooling, pelletizing and drying, a PBCT / PBAT alloy material was obtained, wherein: the intrinsic viscosity was 1.33 dL / g, the number average molecular weight was 84.1 kg / mol, the glass transition temperature was -18.2° C., the melting temperature was 124.2° C., and the melt index was 3.9 g / 10 min;

[0052] (2) The dried alloy material was then added to a single screw extruder film blowing machine, and the feeding section, plasticizing section, and outlet template temperatures were set to 170°C, 180°C, and 182°C, respectively. During the blow molding process, the main engine speed was 20 Hz, and the feed speed was 2.0 Hz. After air cooling and stretching blow molding, the stretch ratio was 40, and the final PBCT / PBAT alloy material film thickness was 25-30 μm, and the water vapor permeability coefficient was 6.0×10 -14 g cm / cm 2 ·s·Pa.

[0053] Example 3. Rapid preparation of a reactive compatibilized high-barrier PBCT / PBAT alloy material and processing method for blow molded products

[0054] (1) 200 g of self-made PBCT with an aromatic content of 49% was thoroughly mixed with 800 g of commercially available PBAT, and the mixture was added to a twin-screw extruder. The processing temperatures from the feed inlet to the die head of the twin-screw extruder were 175 °C, 180 °C, 182 °C, 182 °C, 185 °C, 190 °C, and 180 °C respectively. The main motor speed was 25 Hz, and the feeding speed was 4.0 Hz. After water cooling, pelletizing, and drying, a PBCT / PBAT alloy material was obtained, where: the intrinsic viscosity was 1.40 dL / g, the number-average molecular weight was 90.2 kg / mol, the glass transition temperature was -27.4 °C, the melting temperature was 122.5 °C, and the melt index was 2.6 g / 10 min;

[0055] (2) Subsequently, the dried alloy material was added to a single-screw extrusion blow molding machine. The temperatures of the feeding section, plasticizing section, and die head were set at 170 °C, 180 °C, and 182 °C respectively. During the blow molding process, the main motor speed was 20 Hz, and the feeding speed was 2.0 Hz. After air cooling and stretching, a film was blown. The draw ratio was 40. The final thickness of the PBCT / PBAT alloy material film was 20 - 25 μm, and the water vapor transmission coefficient was 9.1×10 -14 g·cm / cm 2 ·s·Pa.

[0056] Example 4. Rapid preparation of a reactive compatibilized high-barrier PBCT / PBAT alloy material and processing method for blow molded products

[0057] (1) 200 g of self-made PBCT with an aromatic content of 58% was thoroughly mixed with 800 g of commercially available PBAT, and the mixture was added to a twin-screw extruder. The processing temperatures from the feed inlet to the die head of the twin-screw extruder were 180 °C, 182 °C, 185 °C, 185 °C, 187 °C, 190 °C, and 180 °C respectively. The main motor speed was 25 Hz, and the feeding speed was 4.0 Hz. After water cooling, pelletizing, and drying, a PBCT / PBAT alloy material was obtained, where: the intrinsic viscosity was 1.38 dL / g, the number-average molecular weight was 87.6 kg / mol, the glass transition temperature was -27.8 °C, the melting temperature was 127.3 °C, and the melt index was 3.1 g / 10 min;

[0058] (2) Subsequently, the dried alloy material was added to a single-screw extrusion blow molding machine. The temperatures of the feeding section, plasticizing section, and die head template were set at 180 °C, 190 °C, and 192 °C respectively. During the blow molding process, the main machine speed was 20 Hz and the feeding speed was 2.0 Hz. After air cooling and stretching, a film was formed. The stretching ratio was 40. The finally obtained PBCT / PBAT alloy material film had a thickness of 20 - 25 μm, and the water vapor transmission coefficient was 8.8×10 -14 g·cm / cm 2 ·s·Pa.

[0059] Example 5. Method for Rapid Preparation of Reactive Compatibilized High-Barrier PBCT / PBAT Alloy Material and Processing of Blow-Molded Products

[0060] (1) 800 g of self-made PBCT with an aromatic content of 49% was fully mixed with 200 g of commercially available PBAT, and the mixture was added to a twin-screw extruder. The processing temperatures from the feed inlet to the die head of the twin-screw extruder were 175 °C, 180 °C, 182 °C, 182 °C, 185 °C, 190 °C, and 180 °C respectively. The main machine speed was 25 Hz and the feeding speed was 4.0 Hz. After water cooling, pelletizing, and drying, a PBCT / PBAT alloy material was obtained, where: the intrinsic viscosity was 1.27 dL / g, the number-average molecular weight was 76.7 kg / mol, the glass transition temperature was -8.3 °C, the melting temperature was 128.2 °C, and the melt index was 5.7 g / 10 min;

[0061] (2) Subsequently, the dried alloy material was added to a single-screw extrusion blow molding machine. The temperatures of the feeding section, plasticizing section, and die head template were set at 170 °C, 180 °C, and 182 °C respectively. During the blow molding process, the main machine speed was 20 Hz and the feeding speed was 2.0 Hz. After air cooling and stretching, a film was formed. The stretching ratio was 40. The finally obtained PBCT / PBAT alloy material film had a thickness of 20 - 25 μm, and the water vapor transmission coefficient was 3.0×10 -14 g·cm / cm 2 ·s·Pa.

[0062] Example 6. Method for Rapid Preparation of Reactive Compatibilized High-Barrier PBCT / PBAT Alloy Material and Processing of Blow-Molded Products

[0063] (1) 800 g of self-made PBCT with an aromatic content of 58% was thoroughly mixed with 200 g of commercially available PBAT, and the mixture was added to a twin-screw extruder. The processing temperatures from the feed inlet to the die head of the twin-screw extruder were 180 °C, 182 °C, 185 °C, 185 °C, 187 °C, 190 °C, and 180 °C respectively. The main motor speed was 25 Hz, and the feeding speed was 4.0 Hz. After water cooling, pelletizing, and drying, a PBCT / PBAT alloy material was obtained, with: intrinsic viscosity of 1.29 dL / g, number-average molecular weight of 82.9 kg / mol, glass transition temperature of -7.8 °C, melting temperature of 138.9 °C, and melt index of 4.9 g / 10 min;

[0064] (2) Subsequently, the dried alloy material was added to a single-screw extrusion blow molding machine. The temperatures of the feeding section, plasticizing section, and die head template were set at 180 °C, 190 °C, and 192 °C respectively. During the blow molding process, the main motor speed was 20 Hz, and the feeding speed was 2.0 Hz. After air cooling and stretching blow molding into a film, the draw ratio was 40. The final thickness of the PBCT / PBAT alloy material film was 20 - 25 μm, and the water vapor transmission coefficient was 2.4×10 -14 g·cm / cm 2 ·s·Pa.

[0065] Comparative Example 1 Rapid Preparation of PBST / PBAT Alloy Material and Processing of Blow-Molded Products

[0066] (1) 500 g of commercially available PBST was thoroughly mixed with 500 g of commercially available PBAT, and the mixture was added to a twin-screw extruder. The processing temperatures from the feed inlet to the die head of the twin-screw extruder were 180 °C, 182 °C, 185 °C, 185 °C, 187 °C, 190 °C, and 180 °C respectively. The main motor speed was 25 Hz, and the feeding speed was 4.0 Hz. After water cooling, pelletizing, and drying, a PBST / PBAT alloy material was obtained, with: intrinsic viscosity of 1.17 dL / g, number-average molecular weight of 51.8 kg / mol, glass transition temperatures of -29.7 and -15.3 °C, melting temperatures of 119.2 and 129.8 °C, and melt index of 9.4 g / 10 min;

[0067] (2) Subsequently, the dried alloy material was added to a single-screw extrusion blow molding machine. The temperatures of the feeding section, plasticizing section, and die head template were set at 180 °C, 190 °C, and 192 °C respectively. During the blow molding process, the main motor speed was 20 Hz, and the feeding speed was 2.0 Hz. After air cooling and stretching blow molding into a film, the draw ratio was 40. The final thickness of the PBST / PBAT alloy material film was 30 - 40 μm, and the water vapor transmission coefficient was 19.4×10 -14 g·cm / cm 2 ·s·Pa.

[0068] Result analysis:

[0069] 1. In Comparative Example 1, a PBST / PBAT alloy material was prepared by the same steps as in Example 1 and subjected to blow molding. Although a degradable film with a high draw ratio could also be obtained from this PBST / PBAT alloy material, the glass transition temperature and melting temperature of the alloy material were similar to those of PBST and PBAT, and there was no obvious approach to each other, and the water barrier performance decreased. This shows that the blend compatibility of PBST and PBAT is poor without adding a blend compatibilizer, which is likely to cause a decrease in performance.

[0070] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation of the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A reactive and compatible high barrier PBCT / PBAT alloy material, It is characterized in that It has the structure shown below: Among them, m, n, x, and y are natural numbers, ranging from 20 to 300; m represents the number of repeating units of the aromatic chain segment in PBCT in the main chain of the high-barrier PBCT / PBAT alloy material; n represents the number of repeating units of the aliphatic chain segment of PBCT in the main chain of the high-barrier PBCT / PBAT alloy material; x represents the number of repeating units of the aliphatic chain segment of PBAT in the main chain of the high-barrier PBCT / PBAT alloy material, and y represents the number of repeating units of the aromatic chain segment of PBAT in the main chain of the high-barrier PBCT / PBAT alloy material; In terms of weight percentage, PBCT accounts for 20 to 80% in the high barrier PBCT / PBAT alloy material.

2. The PBCT / PBAT alloy material according to claim 1, It is characterized in that The PBCT / PBAT alloy material is prepared by melt extrusion blending of an aromatic-aliphatic copolymer PBCT with an ester group as the end capping and PBAT with a hydroxyl group as the end capping.

3. The PBCT / PBAT alloy material according to claim 2, It is characterized in that In terms of molar percentage, the number of aromatic segments in the PBCT accounts for 1 to 99% of the total number of aliphatic segments and aromatic segments in the PBCT.

4. The PBCT / PBAT alloy material according to claim 3, It is characterized in that In terms of molar percentage, the number of aromatic segments in the PBCT accounts for 40-60% of the total number of aliphatic segments and aromatic segments in the PBCT.

5. The PBCT / PBAT alloy material according to any one of claims 1 to 4, It is characterized in that The high barrier PBCT / PBAT alloy material has a characteristic viscosity of 1.0 to 2.0 dL / g, a number average molecular weight of 50 to 100 kg / mol, a glass transition temperature of -30 to 44°C, a melting temperature of 117 to 230°C, and a melt index of 3.0 to 20 g / 10 min.

6. The PBCT / PBAT alloy material according to claim 2, It is characterized in that The preparation was carried out by the following steps: (1) PBCT and PBAT are fully mixed in a certain ratio to obtain a premix; (2) Extruding the premixed material into pellets through a twin-screw extruder, wherein the temperature of the twin-screw extruder is 160 to 260° C., the rotation speed is 10 to 30 Hz, and the feeding speed is 1.0 to 5.0 Hz. The extruded melt is water-cooled, drawn, air-dried and pelletized to obtain a PBCT / PBAT alloy material; The mass ratio of PBCT to PBAT is 20:80 to 80:

20.

7. The PBCT / PBAT alloy material according to claim 6, It is characterized in that The number of aromatic segments in the PBCT accounts for 1 to 99% of the total number of aliphatic segments and aromatic segments in the PBCT; The number of aromatic segments in the PBAT accounts for 47% of the total number of aliphatic segments and aromatic segments in the PBAT.

8. A blow-molded product made of a high-barrier PBCT / PBAT alloy material, characterized in that, the raw material of the blow-molded product comprises the PBCT / PBAT alloy material according to any one of claims 1-4, 6-7.

9. The blow-molded product according to claim 8, characterized in that, blow molding is carried out by using a single-screw melt extrusion blown film machine, and the specific steps are as follows: the dried alloy material is put into the feeding section of the single-screw melt extrusion blown film machine to be completely melted and plasticized; the melted and plasticized masterbatch is conveyed by the screw to the discharge port and is formed by air cooling and stretching blow molding to obtain the blow-molded product of the PBCT / PBAT alloy material; wherein: the template temperature of the feeding section is set between 160 and 260 °C; the template temperature of the plasticizing section is set between 170 and 250 °C; the main machine speed is 10-30 Hz; the feeding speed is 1.0-5.0 Hz.

Images