Degradable plastic bottle and preparation method thereof

Abstract

The invention relates to the technical field of plastic bottles, and particularly discloses a degradable plastic bottle and a preparation method thereof. The degradable plastic bottle is prepared from the following raw materials in parts by weight: 50 to 70 parts of polylactic acid, 20 to 30 parts of corn starch, 2 to 5 parts of bamboo fiber, 5 to 10 parts of nano cellulose, 5 to 10 parts of triethyl citrate, 1 to 5 parts of photodegradation agent and 1 to 2 parts of antioxidant. The impact strength, the tensile strength and the elongation at break of the degradable plastic bottle can reach 7.0 KJ / m < 2 >, 40.0 Mpa and 74% at most, and the mechanical property of the degradable plastic bottle is improved.

Description

Technical Field

[0001] The present application relates to the technical field of plastic bottles, and more specifically, to a degradable plastic bottle and a preparation method thereof. Background Art

[0002] Plastic bottles are low-cost and widely used in food, medicine, chemical industry and other fields. With the improvement of global environmental awareness, the use of degradable materials has become an important trend in plastic products. However, existing plastic bottles are mainly made of non-degradable materials such as polypropylene, polyethylene and polyethylene terephthalate. After being discarded, they are difficult to decompose in nature, causing long-term environmental pollution. Therefore, the development of a degradable plastic bottle has become an important research direction.

[0003] In the related art, polylactic acid and starch are used as the main raw materials of plastic bottles to make the plastic bottles degradable, but the mechanical properties of plastic bottles made of natural degradable materials are unstable. Summary of the invention

[0004] In order to improve the mechanical properties of a degradable plastic bottle, the present application provides a degradable plastic bottle and a preparation method thereof.

[0005] In the first aspect, the present application provides a degradable plastic bottle, which adopts the following technical solution: A degradable plastic bottle comprises the following raw materials in parts by weight: 50-70 parts of polylactic acid, 20-30 parts of corn starch, 3-5 parts of bamboo fiber, 5-10 parts of nano cellulose, 5-10 parts of triethyl citrate, 1-5 parts of photodegradation agent and 1-2 parts of antioxidant.

[0006] The degradable plastic bottle of the present application can select 50-70 parts of polylactic acid, 20-30 parts of corn starch, 2-5 parts of bamboo fiber, 5-10 parts of nanocellulose, 5-10 parts of triethyl citrate, 1-5 parts of photodegradation agent, and 1-2 parts of antioxidant. Any value within the respective ranges can be selected, and the mechanical properties of the degradable plastic bottle can be improved.

[0007] By adopting the above technical scheme, polylactic acid can be decomposed into carbon dioxide and water in the natural environment, and starch is also biodegradable. Polylactic acid and starch are used as the main raw materials to make plastic bottles degradable. Bamboo fiber is added as a reinforcing material to improve the tensile strength and impact resistance of plastic bottles, while ensuring the degradability of plastic bottles. Triethyl citrate is added as a plasticizer to improve the impact resistance of plastic bottles. The addition of nanocellulose can significantly improve the mechanical properties of degradable plastic bottles. At the same time, nanocellulose itself is biodegradable, which can further promote the degradation of polylactic acid. In addition, nanocellulose has the characteristics of high strength and degradability, and bamboo fiber has the characteristics of high toughness. Nanocellulose and bamboo fiber are added to the raw materials of plastic bottles at the same time, which not only improves the mechanical properties of degradable plastic bottles, but also improves the dispersibility of bamboo fiber in the raw materials, thereby further enhancing the role of bamboo fiber in improving mechanical properties in the raw materials.

[0008] Preferably, a degradable plastic bottle comprises the following raw materials in parts by weight: 55-65 parts of polylactic acid, 22-27 parts of corn starch, 3.5-4.5 parts of bamboo fiber, 7-9 parts of nanocellulose, 6-8 parts of triethyl citrate, 3-4 parts of photodegradant, and 1.2-1.8 parts of antioxidant.

[0009] The degradable plastic bottle of the present application can select 55-65 parts of polylactic acid, 22-27 parts of corn starch, 3.5-4.5 parts of bamboo fiber, 7-9 parts of nanocellulose, 6-8 parts of triethyl citrate, 3-4 parts of photodegradation agent, and 1.2-1.8 parts of antioxidant. Any value within the respective ranges can be selected, and the mechanical properties of the degradable plastic bottle can be improved.

[0010] Preferably, the weight ratio of the bamboo fiber to the nanocellulose is 1:(1.5-2.5).

[0011] By adopting the above technical solution and adjusting the weight ratio of bamboo fiber and nanocellulose, the mechanical properties of the degradable plastic bottle can be further improved.

[0012] Preferably, the nanocellulose is prepared by modification, specifically, dispersing the nanocellulose in water, adding graphene oxide and ultrasonically dispersing at 55-65° C. for 25-35 min, removing unabsorbed graphene oxide by centrifugation, washing, and vacuum drying at 75-85° C. for 24 h to obtain modified nanocellulose.

[0013] By adopting the above technical scheme, graphene oxide is adsorbed on the surface of nanocellulose to modify the nanocellulose, thereby improving the dispersibility of nanocellulose in the degradable plastic bottle raw material and improving the mechanical properties of the plastic bottle. Adding graphene oxide to the raw material has the effect of improving the mechanical properties, so graphene oxide has a dual role.

[0014] Preferably, the weight ratio of the nanocellulose to graphene oxide is 1:(1.5-2.5).

[0015] By adopting the above technical solution and adjusting the weight ratio of nanocellulose to graphene oxide, the dispersibility of nanocellulose in the raw material of degradable plastic bottles can be further improved, thereby further improving the mechanical properties of the degradable plastic bottles.

[0016] Preferably, the degradable plastic bottle further comprises the following raw materials in parts by weight: 15-25 parts of algae powder.

[0017] By adopting the above technical scheme and adding algae powder, on the one hand, the mechanical properties of the degradable plastic bottle can be improved, and on the other hand, nanocellulose can be used as a dispersing aid for the algae powder, thereby improving the dispersibility of the algae powder in the degradable plastic bottle raw materials, thereby improving the mechanical properties of the degradable plastic bottle.

[0018] Preferably, 1-5 parts by weight of maleic anhydride grafted polylactic acid is added to the degradable plastic bottle raw material.

[0019] By adopting the above technical scheme and adding maleic anhydride grafted polylactic acid to the raw material of the degradable plastic bottle, the dispersibility of the algae powder in the degradable plastic bottle can be further improved, thereby further improving the mechanical properties of the degradable plastic bottle.

[0020] In a second aspect, the present application provides a method for preparing any of the above-mentioned degradable plastic bottles.

[0021] A method for preparing a degradable plastic bottle comprises the following steps: mixing various raw materials, heating and melting, stirring and plasticizing, making embryos, forming films, blowing and molding, demoulding, and sterilizing to obtain the degradable plastic bottle.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: (1) This application controls the type and dosage of each raw material in the degradable plastic bottle to make the impact strength, tensile strength and elongation at break of the plastic bottle reach 23.0-24.6KJ / m 2 , 64.0-65.2Mpa, 63-64%, which improves the mechanical properties of degradable plastic bottles.

[0023] (2) In this application, nanocellulose is modified and the weight ratio of nanocellulose and graphene oxide is adjusted to make the impact strength, tensile strength and elongation at break of the plastic bottle 26.3-27.2 KJ / m respectively. 2 , 68.8-70.1Mpa, 67-68%, which improved the mechanical properties of the degradable plastic bottles.

[0024] (3) This application adds algae powder to the plastic bottle raw material and controls its dosage, so that the impact strength, tensile strength and elongation at break of the plastic bottle can reach a maximum of 29.2-30.5KJ / m 2 , 72.3-74.2Mpa, 70-71%, further improving the mechanical properties of the degradable plastic bottles.

[0025] (4) This application adds maleic anhydride grafted polylactic acid to the plastic bottle raw material and controls its dosage, so that the impact strength, tensile strength and elongation at break of the biodegradable plastic bottle can reach a maximum of 32.7-33.5KJ / m 2 , 76.3-77.8Mpa, 73-74%, which improved the mechanical properties of the degradable plastic bottles. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with specific embodiments.

[0027] The following raw materials in this application are all commercially available products, and are intended to make the raw materials of this application fully disclosed, and should not be understood as limiting the source of the raw materials. Specifically: polylactic acid, brand FY804; corn starch, effective substance content 99%; bamboo fiber, nanocellulose, mass fraction 25%; triethyl citrate, model plasticizer TEC; photodegradant, titanium dioxide, particle size 5nm; antioxidant, model antioxidant 1076; graphene oxide, effective substance content 99%, model FH-661; algae powder, spirulina powder, effective substance content 50%, XYH-LXZ-050; maleic anhydride grafted polylactic acid, model PLA-g-DVB / MAN.

[0028] The following is an example of the preparation of modified ultrafine mica powder Preparation Example 1 The modified nanocellulose of Preparation Example 1 is prepared by the following steps: 1 kg of nanocellulose was dispersed in 100 L of water, and 1 kg of graphene oxide was added and ultrasonically dispersed at 60°C for 30 min. The unabsorbed graphene oxide was removed by centrifugation, washed, and vacuum dried at 80°C for 24 h to obtain modified nanocellulose.

[0029] Preparation Example 2-5 The preparation methods of the modified nanocelluloses of Preparation Examples 2-5 are the same as those of Preparation Example 1, except that the amounts of graphene oxide used are 1.5 kg, 2 kg, 2.5 kg and 3 kg, respectively, and the types and amounts of other raw materials are the same as those of Preparation Example 1.

[0030] Example 1

[0031] The degradable plastic bottle of Example 1 is prepared by the following preparation method: According to the dosage in Table 1, the raw materials were mixed, heated to 180°C, heated for 25 minutes, melted, stirred and plasticized to make embryos, the injection molding pressure was 2 MPa, the film was closed, and the film was blown for 2 seconds under the conditions of blowing pressure of 1 MPa and blowing temperature of 80°C. The film was cooled to 10°C, demolded after cooling for 4 seconds, and sterilized with ozone for 15 minutes to obtain a degradable plastic bottle.

[0032] Embodiment 2-5 The preparation method of the degradable plastic bottle of Examples 2-5 is the same as that of Example 1, except that the dosage of each raw material is different, as shown in Table 1. Table 1 Amount of each raw material in the degradable plastic bottle of Example 1-5 (kg)

[0033] Embodiment 6-10 The preparation method of the degradable plastic bottles of Examples 6-10 is the same as that of Example 3, except that the nanocellulose in the raw material of the degradable plastic bottles is the modified nanocellulose prepared in Preparation Examples 1-5, and the types and dosages of other raw materials are the same as those in Example 3.

[0034] Embodiment 11

[0035] The preparation method of the degradable plastic bottle of Example 11 is the same as that of Example 10, except that it further includes 10 kg of algae powder, and the types and amounts of other raw materials are the same as those of Example 10.

[0036] Examples 12-15 The preparation method of the degradable plastic bottle of Examples 12-15 is the same as that of Example 11, except that the dosage of algae powder is 15kg, 20kg, 25kg, and 30kg, respectively, and the types and dosages of other raw materials are the same as those of Example 11.

[0037] Example 16

[0038] The preparation method of the degradable plastic bottle of Example 16 is the same as that of Example 13, except that it further includes 0.5 kg of maleic anhydride grafted polylactic acid, and the other raw material types and dosages are the same as those of Example 13.

[0039] Examples 17-20 The preparation method of the degradable plastic bottle in Examples 17-20 is the same as that in Example 16, except that the dosage of maleic anhydride grafted polylactic acid is 1kg, 3kg, 5kg, and 5.5kg, respectively, and the types and dosages of other raw materials are the same as those in Example 16.

[0040] Comparative Example 1 The preparation method of the degradable plastic bottle of Comparative Example 1 is the same as that of Example 1, except that an equal amount of nanocellulose in the degradable plastic bottle is replaced by bamboo fiber, and the types and dosages of other raw materials are the same as those of Example 1.

[0041] Comparative Example 2 The preparation method of the degradable plastic bottle of Comparative Example 2 is the same as that of Example 1, except that an equal amount of bamboo fiber in the degradable plastic bottle is replaced by nanocellulose, and the types and dosages of other raw materials are the same as those of Example 1.

[0042] Performance Testing The performance of the plastic bottles obtained in different Examples 1-20 and Comparative Examples 1-2 was tested respectively, and the test results are shown in Table 2.

[0043] Impact strength: The impact strength of plastic bottles was tested according to GB / T1043-1993, see Table 2 for details; Tensile strength: The tensile strength of plastic bottles was tested according to GB / T1040-1992, see Table 2 for details; Elongation at break: According to GB / T1040.1-2006, the elongation at break of plastic bottles was tested, see Table 2 for details Table 2 Performance test results of different plastic bottles

[0044] The test results in Table 2 show that the impact strength, tensile strength and elongation at break of the biodegradable plastic bottle obtained in this application can reach up to 7.0 KJ / m 2 , 40.0Mpa, 74%, with high mechanical properties.

[0045] Combined with the performance test data of the plastic bottles in Examples 1-5, it can be seen that the impact strength, tensile strength and elongation at break of the degradable plastic bottles in Examples 2-4 are 23.0-24.6 KJ / m 2 , 64.0-65.2Mpa, 63-64%, all higher than Example 1 and Example 5, indicating that the weight ratio of bamboo fiber to nanocellulose in the raw material of the degradable plastic bottle is 1: (1.5-2.5) which is more suitable and improves the mechanical properties of the degradable plastic bottle.

[0046] Combined with the performance test data of the plastic bottles in Examples 6-10, it can be seen that the impact strength, tensile strength and elongation at break of the degradable plastic bottles in Examples 7-9 are 26.3-27.2 KJ / m 2 , 68.8-70.1Mpa, 67-68%, all higher than Example 6 and Example 10, indicating that when the weight ratio of nanocellulose to graphene oxide is 1:(1.5-2.5), it is more appropriate and improves the mechanical properties of the degradable plastic bottle.

[0047] Combined with the performance test data of the plastic bottles in Examples 11-15, it can be seen that the impact strength, tensile strength and elongation at break of the degradable plastic bottles in Examples 12-14 can reach a maximum of 29.2-30.5 KJ / m 2 , 72.3-74.2Mpa, 70-71%, all higher than Example 11 and Example 15, indicating that it is more appropriate to add 15-25 parts by weight of algae powder to the raw materials, which improves the mechanical properties of the degradable plastic bottle.

[0048] Combined with the performance test data of the plastic bottles in Examples 16-20, it can be seen that the impact strength, tensile strength and elongation at break of the degradable plastic bottles in Examples 17-19 can reach up to 32.7-33.5 KJ / m 2 , 76.3-77.8Mpa, 73-74%, all higher than Example 16 and Example 17, indicating that it is more appropriate to add 1-5 parts by weight of maleic anhydride grafted polylactic acid to the raw materials, which improves the mechanical properties of the degradable plastic bottle.

[0049] In addition, based on the performance test data of the degradable plastic bottles of Comparative Examples 1-3 and Example 1, it was found that adding nanocellulose and bamboo fiber to the raw materials of the degradable plastic bottles can improve the mechanical properties of the degradable plastic bottles to varying degrees.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A degradable plastic bottle, characterized in that: The invention comprises the following raw materials in parts by weight: 50-70 parts of polylactic acid, 20-30 parts of corn starch, 2-5 parts of bamboo fiber, 5-10 parts of nanocellulose, 5-10 parts of triethyl citrate, 1-5 parts of photodegradation agent and 1-2 parts of antioxidant; the nanocellulose is prepared by modification, specifically, the nanocellulose is dispersed in water, graphene oxide is added and ultrasonically dispersed at 55-65° C. for 25-35 minutes, non-absorbed graphene oxide is removed by centrifugation, washing is performed, and vacuum drying is performed at 75-85° C. for 24 hours to obtain the modified nanocellulose.

2. The degradable plastic bottle according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 55-65 parts of polylactic acid, 22-27 parts of corn starch, 3.5-4.5 parts of bamboo fiber, 7-9 parts of nano cellulose, 6-8 parts of triethyl citrate, 3-4 parts of photodegradant and 1.2-1.8 parts of antioxidant.

3. The degradable plastic bottle according to claim 1, characterized in that: The weight ratio of the bamboo fiber to the nanocellulose is 1:(1.5-2.5).

4. The degradable plastic bottle according to claim 1, characterized in that: The weight ratio of the nanocellulose to graphene oxide is 1:(1.5-2.5).

5. The degradable plastic bottle according to claim 1, characterized in that: The degradable plastic bottle further comprises the following raw materials in parts by weight: 15-25 parts of algae powder.

6. The degradable plastic bottle according to claim 5, characterized in that: 1-5 parts by weight of maleic anhydride grafted polylactic acid is added to the degradable plastic bottle raw material.

7. A method for preparing a degradable plastic bottle according to any one of claims 1 to 6, characterized in that: The method comprises the following operating steps: mixing various raw materials, heating and melting, stirring and plasticizing, making embryos, forming films, blowing and molding, demoulding, and sterilizing to obtain degradable plastic bottles.

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