Degradable flattening-resistant pocket as well as preparation method and application thereof

Abstract

The invention relates to the technical field of packaging materials, and particularly discloses a degradable flattening-resistant pocket as well as a preparation method and application thereof. The invention discloses a degradable flattening-resistant pocket which is prepared from the following components: 65 to 75 parts of polylactic acid, 25 to 35 parts of polyhydroxyalkanoate and 10 to 20 parts of auxiliary master batch, the assistant master batch is prepared by melt extrusion of the following components: 20 parts of polyhydroxyalkanoate, 6-10 parts of modified nano titanium dioxide, 6-10 parts of a plasticizer, 1-4 parts of a lubricant and 1-2 parts of an antioxidant; the modified nano titanium dioxide is prepared from maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol and nano titanium dioxide according to the weight ratio of (10 to 15): (0.1 to 0.5): (4 to 8): (2 to 6): (15 to 20). By utilizing the technical scheme of the invention, the prepared flat pocket material has excellent tensile strength, elongation at break and tear resistance, and also has good degradability.

Description

Technical Field

[0001] This application relates to the technical field of packaging materials, specifically to a biodegradable resistant flattened bag, its preparation method, and its application. Background Technology

[0002] Currently, flat-pack packaging materials are widely used in food, medical, and other fields. However, with increasing environmental awareness, traditional plastic packaging has caused serious environmental pollution due to its non-degradability. Therefore, biodegradable packaging materials have gradually become a research hotspot. Common biodegradable packaging materials mainly include polylactic acid (PLA), starch-based materials, and cellulose-based materials. PLA has good biodegradability and certain mechanical strength, but it is brittle and easily breaks; starch-based materials have low cost, but are highly hygroscopic and have poor mechanical properties; cellulose-based materials are environmentally friendly, but lack compression and tear resistance. In addition, some technologies improve performance by adding nanofillers or fiber reinforcement materials, but these methods often lead to increased processing difficulty or higher costs.

[0003] Based on the above, existing biodegradable packaging materials generally suffer from insufficient mechanical properties, particularly in terms of compression resistance and tear resistance. They are prone to deformation or damage during transportation and storage, affecting the product's protective effect and user experience. Furthermore, the preparation processes for some high-performance biodegradable materials are complex and costly, hindering large-scale application.

[0004] Therefore, there is a need to provide a biodegradable flat bag packaging material with good mechanical properties. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a biodegradable resistant flattened bag, its preparation method, and its application.

[0006] This application provides a biodegradable resistant flattened bag, which is made from the following components in parts by weight: 65-75 parts of polylactic acid, 25-35 parts of polyhydroxyalkanoate, and 10-20 parts of additive masterbatch. The additive masterbatch is obtained by melt extrusion of the following components in parts by weight: 20 parts of polyhydroxy fatty acid ester, 6-10 parts of modified nano titanium dioxide, 6-10 parts of plasticizer, 1-4 parts of lubricant, and 1-2 parts of antioxidant. The modified nano-titanium dioxide is prepared from maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide in a weight ratio of 10-15:0.1-0.5:4-8:2-6:15-20.

[0007] The formulation designed in this application uses polylactic acid (PLA) and polyhydroxyalkanoates (PHA) as the main raw materials. PLA is a rigid material, providing high strength and high modulus; PHA has flexibility, which can improve elongation at break. The two are melt-blended to form a "rigid-flexible" synergistic system. PHA acts as a toughening phase dispersed in the PLA matrix. Under stress, it absorbs energy through the crazing-shear banding mechanism. At the same time, the flexible segments of PHA can effectively transfer stress and avoid stress concentration, thereby simultaneously improving tensile strength and elongation at break. Moreover, both PLA and PHA are biodegradable materials with good biodegradability and are environmentally friendly.

[0008] The reinforcing effect of modified nano-titanium dioxide: After surface modification, nano-titanium dioxide exhibits good interfacial compatibility with the polymer matrix. The nanoparticles are uniformly dispersed in the matrix, forming a three-dimensional network structure. Through physical cross-linking points and stress transfer, this effectively hinders molecular chain slippage, significantly improving the tensile strength and tear resistance of the material. Simultaneously, the nanoparticles can induce matrix crystallization, increasing crystallinity and further enhancing mechanical properties. Plasticizer molecules insert between polymer molecular chains, increasing interchain spacing, reducing intermolecular forces, and improving chain segment mobility, thereby improving the material's flexibility and processing performance. Lubricants reduce melt viscosity, improve processing fluidity, and simultaneously reduce friction between molecular chains, preventing stress concentration and further increasing elongation at break. Antioxidants inhibit oxidative degradation of the polymer during processing and use by capturing free radicals and decomposing peroxides, ensuring the material's stability during storage and use, and preventing premature degradation that could affect performance.

[0009] Meanwhile, this application obtains additive masterbatch by melt extrusion of polyhydroxy fatty acid ester, modified nano titanium dioxide, plasticizer, lubricant, and antioxidant. This process can achieve uniform dispersion of additives such as nanoparticles, plasticizers, lubricants, and antioxidants in the polymer matrix, avoid agglomeration, and give full play to the role of each component. The masterbatch process can also improve the compatibility between additives and matrix, improve processing performance, and finally obtain biodegradable plastic bag material with excellent comprehensive performance.

[0010] Preferably, the biodegradable resistant flattened bag is made from the following components in parts by weight: 67-73 parts of polylactic acid, 27-33 parts of polyhydroxyalkanoate, and 13-18 parts of additive masterbatch.

[0011] Preferably, the additive masterbatch is obtained by melt extrusion of the following components in parts by weight: 20 parts of polyhydroxy fatty acid ester, 7-9 parts of modified nano titanium dioxide, 7-9 parts of plasticizer, 2-3 parts of lubricant, and 1.2-1.8 parts of antioxidant.

[0012] Preferably, the modified nano-titanium dioxide is prepared by adding dicumyl peroxide to maleic anhydride, mixing evenly, then adding adipic acid and dipropylene glycol, reacting at room temperature for 40-60 min, then adding nano-titanium dioxide, reacting at room temperature for 60-90 min, and then extruding at a temperature of 210-240℃ to obtain the modified nano-titanium dioxide; the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide is 12-14:0.2-0.4:5-7:3-5:16-18.

[0013] Experimental analysis shows that the modified nano-titanium dioxide prepared by using maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide in the above weight ratio can further improve the performance of the flat bag material.

[0014] Preferably, the plasticizer is selected from any one of tributyl citrate, acetylated tributyl citrate, epoxidized soybean oil, and polyethylene glycol.

[0015] Preferably, the plasticizer is composed of epoxidized soybean oil and polyethylene glycol in a weight ratio of 7-11:1-3; the polyethylene glycol has a molecular weight of 1000-2000.

[0016] In one specific implementation, the plasticizer contains epoxidized soybean oil and polyethylene glycol with molecular weights of 7:1, 7:2, 7:3, 8:1, 8:2, 8:3, 9:1, 9:2, 9:3, 10:1, 10:2, 10:3, 11:1, 11:2, and 11:3.

[0017] Experimental analysis shows that using the above-mentioned weight ratio of epoxidized soybean oil and polyethylene glycol as plasticizers in this application can further improve the performance of flat bag materials.

[0018] Preferably, the antioxidant is selected from any one of hindered phenolic antioxidants and phosphite antioxidants; the lubricant is selected from any one of stearic acid, calcium stearate, zinc stearate, and polyethylene wax.

[0019] This application also provides a method for preparing the aforementioned degradable resistant flattened bag, comprising the following steps: According to the weight parts, polyhydroxy fatty acid ester, modified nano titanium dioxide, plasticizer, lubricant and antioxidant are mixed evenly and melt extruded at 170-220℃ to obtain additive masterbatch; According to the weight parts, polylactic acid, polyhydroxy fatty acid ester and auxiliary masterbatch are mixed evenly and melt extruded at 170-220℃ to obtain a premix; then blown film is performed at 160-230℃ to make bags to obtain the biodegradable resistant flat bag.

[0020] Preferably, the process parameters for blown film are: a blow-up ratio of 2.5-3.5:1, a traction speed of 10-20 m / min, a zone 1 temperature of 160-180℃, a zone 2 temperature of 190-210℃, a zone 3 temperature of 210-220℃, a zone 4 temperature of 220-230℃, and a zone 5 temperature of 190-210℃.

[0021] This application also provides the application of the aforementioned biodegradable and resistant flattened bag in food packaging and medical product packaging.

[0022] In summary, the technical solution of this application has the following effects: This application, by designing the types and amounts of raw material components and matching them with specific process methods, produces a flat bag material with excellent tensile strength, elongation at break, and tear resistance, while also exhibiting good biodegradability.

[0023] The biodegradable resistant flat bag prepared in this application can be widely used in food packaging, daily necessities packaging, industrial parts packaging and other fields, and has broad market prospects. Detailed Implementation

[0024] The present application will be further described in detail below with reference to embodiments, comparative examples and performance test results. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0025] The polylactic acid (PLA4032D) used in this application is from Natureworks; the polyhydroxyalkanoate (product number S22177) is from Shanghai Yuanye Biotechnology Co., Ltd.; the nano titanium dioxide (JL-TiO2-TA30, particle size 5-30nm) is from Beijing Deco Island Gold Technology Co., Ltd.; the remaining raw materials can be obtained commercially.

[0026] Example

[0027] Example 1

[0028] Example 1 provides a biodegradable resistant flattened bag and its preparation method.

[0029] The method for preparing the biodegradable resistant flattened bag in this embodiment is as follows: Preparation of modified nano-titanium dioxide: Dicumyl peroxide was added to maleic anhydride and mixed evenly. Then adipic acid and dipropylene glycol were added and reacted at room temperature for 50 min. Then nano-titanium dioxide was added and reacted at room temperature for 75 min. Then, the mixture was melt-extruded at an aspect ratio of 25:1, a screw speed of 150 r / min, and 220℃ to obtain modified nano-titanium dioxide. The weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide was 13 g: 0.3 g: 6 g: 4 g: 17 g.

[0030] Preparation of additive masterbatch: 20g of polyhydroxyalkanoate, 8g of modified nano titanium dioxide, 8g of plasticizer (composed of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 9:2), 2.5g of lubricant zinc stearate, and 1.5g of antioxidant (obtained by mixing hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a weight ratio of 1:1) were mixed at 600rpm and 70℃ for 15min until homogeneous. Then, the mixture was melt-extruded to obtain the additive masterbatch. The melt extrusion process parameters were as follows: a twin-screw extruder was used with a length-to-diameter ratio of 35:1, a screw speed of 150r / min, and zone 1 temperature of 175℃, zone 2 temperature of 185℃, zone 3 temperature of 205℃, zone 4 temperature of 215℃, and zone 5 temperature of 195℃.

[0031] Raw material melt extrusion granulation: 70g polylactic acid, 30g polyhydroxy fatty acid ester and 15g auxiliary masterbatch are mixed at 600rpm and 70℃ for 15min, mixed evenly, and then melt extruded to obtain premix. The process parameters of melt extrusion are: using a twin-screw extruder, length-to-diameter ratio of 35:1, screw speed of 150r / min, zone 1 temperature of 175℃, zone 2 temperature of 185℃, zone 3 temperature of 205℃, zone 4 temperature of 215℃, and zone 5 temperature of 195℃.

[0032] Film blowing: The mixture is added to a film blowing machine to obtain a film with a thickness of 0.03mm; the process parameters of film blowing are: blow-up ratio of 3:1, traction speed of 15m / min, zone 1 temperature of 170℃, zone 2 temperature of 200℃, zone 3 temperature of 215℃, zone 4 temperature of 225℃, and zone 5 temperature of 200℃.

[0033] Bag making: The film is heat-sealed, edge-cut, and other processes to make a biodegradable, resistant flat bag.

[0034] Example 2-5 Examples 2-5 provide a biodegradable resistant flattened bag and its preparation method, respectively.

[0035] The difference between the above embodiments and Embodiment 1 is that the amount of each raw material component is different, as shown below.

[0036] In Example 2, the raw material components were: 67g polylactic acid, 33g polyhydroxy fatty acid ester and 13g auxiliary masterbatch.

[0037] In Example 3, the raw material components were: 73g polylactic acid, 27g polyhydroxy fatty acid ester and 18g auxiliary masterbatch.

[0038] In Example 4, the raw material components were: 65g polylactic acid, 35g polyhydroxy fatty acid ester and 10g auxiliary masterbatch.

[0039] In Example 5, the raw material components were: 75g polylactic acid, 25g polyhydroxy fatty acid ester and 20g auxiliary masterbatch.

[0040] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0041] Examples 6-9 Examples 6-9 provide a biodegradable resistant flattened bag and its preparation method, respectively.

[0042] The specific differences between the above embodiments and Embodiment 1 are as follows:

[0043] In Example 6: In the preparation method of modified nano-titanium dioxide, the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide is 12g:0.4g:5g:5g:16g.

[0044] In Example 7: In the preparation method of modified nano-titanium dioxide, the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide is 14g:0.2g:7g:3g:18g.

[0045] In Example 8: In the preparation method of modified nano-titanium dioxide, the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol and nano-titanium dioxide is 10g:0.5g:4g:6g:15g.

[0046] In Example 9: In the preparation method of modified nano-titanium dioxide, the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide is 15g:0.1g:8g:2g:20g.

[0047] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0048] Examples 10-13 Examples 10-13 provide a biodegradable resistant flattened bag and its preparation method, respectively.

[0049] The difference between the above embodiments and Embodiment 1 is that the types of plasticizers are different, as detailed below.

[0050] In Example 10: the plasticizer consists of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 2:9.

[0051] In Example 11: the plasticizer consists of tributyl citrate and polyethylene glycol PEG 2000 in a weight ratio of 9:2.

[0052] In Example 12: the plasticizer consists of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 7:3.

[0053] In Example 13: the plasticizer consists of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 11:1.

[0054] All other process parameters in the above embodiments are the same as those in Embodiment 1.

[0055] Comparative Example Comparative Examples 1-5 Comparative Examples 1-5 each provide a flat bag and a method for preparing it.

[0056] The difference between the above comparative examples and Example 1 is as shown in Table 1.

[0057] In Comparative Example 1, the raw material components were: 30g polylactic acid, 70g polyhydroxy fatty acid ester and 15g auxiliary masterbatch.

[0058] In Comparative Example 2: The preparation method of the auxiliary agent masterbatch is as follows: 20g of polyhydroxy fatty acid ester, 8g of modified nano titanium dioxide, 8g of plasticizer (composed of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 9:2), 2.5g of lubricant zinc stearate, and 1.5g of antioxidant (obtained by mixing hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a weight ratio of 1:1) are mixed at 600rpm and 70℃ for 15min until uniformly mixed, and this mixture is used as the auxiliary agent masterbatch.

[0059] In Comparative Example 3: The preparation method of the auxiliary agent masterbatch is as follows: 20g of polylactic acid, 8g of modified nano titanium dioxide, 8g of plasticizer (composed of epoxidized soybean oil and polyethylene glycol PEG 2000 in a weight ratio of 9:2), 2.5g of lubricant zinc stearate, and 1.5g of antioxidant (obtained by mixing hindered phenolic antioxidant 1010 and phosphite antioxidant 168 in a weight ratio of 1:1) are mixed at 600rpm and 70℃ for 15min until uniformly mixed, which is used as the auxiliary agent masterbatch.

[0060] In Comparative Example 4: In the additive masterbatch, an equal amount of unmodified nano-titanium dioxide was used to replace modified nano-titanium dioxide.

[0061] In Comparative Example 5: In the preparation method of modified nano-titanium dioxide in the auxiliary masterbatch: the weight ratio of maleic anhydride, diisopropylbenzene peroxide, adipic acid, dipropylene glycol and nano-titanium dioxide is 17g:0.1g:8g:2g:13g.

[0062] All other process parameters in the above comparative examples are the same as those in Example 1.

[0063] Performance testing Tensile strength: The tensile strength and elongation at break of the test samples were tested in accordance with GB / T 1040.3.

[0064] Tear strength: The tear strength of the test sample shall be tested in accordance with the provisions of GB / T 16578.2.

[0065] Biodegradation rate: The biodegradation rate of the test samples at 90 days and 120 days was tested in accordance with GB / T 20197.

[0066] Test results are shown in Table 1.

[0067] Table 1. Performance test results of degradation-resistant flattened bags in the examples and comparative examples.

[0068] As can be seen from the test results in Table 1 above and the comparison results between the examples and the comparative examples, this application significantly improves the tensile strength, elongation at break and tear resistance of flat bag materials by designing the types and amounts of raw material components and matching specific process methods, while maintaining good degradability.

[0069] By comparing the test results of Examples 1-5 and Comparative Example 1, it can be seen that the amount of each raw material component has a significant impact on the performance of the flat bag material. In Comparative Example 1, the raw material components were 30g polylactic acid, 70g polyhydroxyalkanoate, and 15g auxiliary masterbatch, resulting in a flat bag material with poor performance. In contrast, the flat bag material prepared using 65-75 parts of polylactic acid, 25-35 parts of polyhydroxyalkanoate, and 10-20 parts of auxiliary masterbatch in this application exhibits excellent performance.

[0070] By comparing the test results of Examples 1, 6-9, and Comparative Examples 2-5, it can be seen that the preparation method of the additive masterbatch has a significant impact on the performance of the flat bag material. In Comparative Example 2, the additive masterbatch was prepared by uniformly mixing polyhydroxyalkanoate, modified nano-titanium dioxide, plasticizer, lubricant, and antioxidant, and directly using this mixture as the additive masterbatch. In Comparative Example 3, polylactic acid was used instead of polyhydroxyalkanoate. In Comparative Example 4, an equal amount of unmodified nano-titanium dioxide was used instead of modified nano-titanium dioxide. In Comparative Example 5, the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide in the additive masterbatch was mismatched, resulting in a flat bag material with poor performance. In contrast, this application uses maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide in a weight ratio of 10-15:0.1-0.5:4-8:2-6:15-20 to prepare modified nano-titanium dioxide, and then uses polyhydroxyalkanoates, modified nano-titanium dioxide, plasticizers, lubricants, and antioxidants to produce additive masterbatch through melt extrusion, which effectively improves the overall performance of the material.

[0071] By comparing the test results of Examples 1 and 10-13, it can be seen that the plasticizer composed of epoxidized soybean oil and polyethylene glycol in a weight ratio of 7-11:1-3 in this application further improves the performance of the flat bag material.

[0072] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A biodegradable, resistant flattening bag, characterized in that, It is prepared from the following components in parts by weight: 65-75 parts of polylactic acid, 25-35 parts of polyhydroxy fatty acid ester, and 10-20 parts of auxiliary masterbatch; The additive masterbatch is obtained by melt extrusion of the following components in parts by weight: 20 parts of polyhydroxy fatty acid ester, 6-10 parts of modified nano titanium dioxide, 6-10 parts of plasticizer, 1-4 parts of lubricant, and 1-2 parts of antioxidant. The modified nano-titanium dioxide is composed of a weight ratio of 10-15: It is prepared by mixing maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide in a ratio of 0.1-0.5:4-8:2-6:15-20.

2. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, It is prepared from the following components in parts by weight: 67-73 parts of polylactic acid, 27-33 parts of polyhydroxy fatty acid ester, and 13-18 parts of auxiliary masterbatch.

3. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, The additive masterbatch is obtained by melt extrusion of the following components in parts by weight: 20 parts of polyhydroxy fatty acid ester, 7-9 parts of modified nano titanium dioxide, 7-9 parts of plasticizer, 2-3 parts of lubricant, and 1.2-1.8 parts of antioxidant.

4. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, The modified nano-titanium dioxide is prepared by adding dicumyl peroxide to maleic anhydride, mixing evenly, then adding adipic acid and dipropylene glycol, reacting at room temperature for 40-60 min, then adding nano-titanium dioxide, reacting at room temperature for 60-90 min, and then extruding at 210-240℃ to obtain the modified nano-titanium dioxide; the weight ratio of maleic anhydride, dicumyl peroxide, adipic acid, dipropylene glycol, and nano-titanium dioxide is 12-14:0.2-0.4:5-7:3-5:16-18.

5. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, The plasticizer is selected from any one of tributyl citrate, acetylated tributyl citrate, epoxidized soybean oil, and polyethylene glycol.

6. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, The plasticizer is composed of epoxidized soybean oil and polyethylene glycol in a weight ratio of 7-11:1-3; the molecular weight of the polyethylene glycol is 1000-2000.

7. The biodegradable, resistant, flattened bag according to claim 1, characterized in that, The antioxidant is selected from any one of hindered phenolic antioxidants and phosphite antioxidants; the lubricant is selected from any one of stearic acid, calcium stearate, zinc stearate, and polyethylene wax.

8. A method for preparing a biodegradable resistant flattened bag as described in any one of claims 1-7, characterized in that, Includes the following steps: According to the weight parts, polyhydroxy fatty acid ester, modified nano titanium dioxide, plasticizer, lubricant and antioxidant are mixed evenly and melt extruded at 170-220℃ to obtain additive masterbatch; According to the weight parts, polylactic acid, polyhydroxy fatty acid ester and auxiliary masterbatch are mixed evenly and melt extruded at 170-220℃ to obtain a premix; then blown film is performed at 160-230℃ to make bags to obtain the biodegradable resistant flat bag.

9. The method for preparing the biodegradable resistant flattened bag according to claim 8, characterized in that, The process parameters for blown film are as follows: blow-up ratio of 2.5-3.5:1, traction speed of 10-20m / min, zone 1 temperature of 160-180℃, zone 2 temperature of 190-210℃, zone 3 temperature of 210-220℃, zone 4 temperature of 220-230℃, and zone 5 temperature of 190-210℃.

10. The application of a biodegradable, resistant flattened bag as described in any one of claims 1-7 in food packaging and medical product packaging.

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