Degradable material for catering and preparation method thereof

Abstract

The application discloses a kind of catering degradable materials and preparation method thereof, and the degradable material is composed of the following weight parts of raw materials: starch 30-50 parts, polylactic acid 20-30 parts, plant fiber 10-20 parts, plasticizer 5-10 parts, crosslinking agent 2-5 parts, water-resistant agent 3-6 parts, degradation regulator 1-3 parts and antibacterial agent 0.5-2 parts.The application significantly improves the compatibility and interfacial bonding force between raw materials by targeted pretreatment and modification of starch and plant fiber;At the same time, the weight ratio of each component is optimized, so that the prepared degradable material has excellent mechanical properties and water and oil resistance, and the degradation rate of the material can be flexibly controlled according to the actual use scene by adding a degradation regulator, which not only ensures the stability of the material during the use cycle, but also quickly degrades after being discarded, without causing pollution to the environment.

Description

Technical Field

[0001] This invention relates to the field of food packaging materials technology, specifically to a biodegradable material for food use and its preparation method. Background Technology

[0002] With the booming development of the catering industry, the demand for disposable catering packaging materials continues to rise. Traditional plastic packaging materials dominate due to their advantages such as low cost and easy processing. However, traditional plastic materials are difficult to degrade in the natural environment, and the white pollution that has accumulated over a long period of time has become a global environmental problem, seriously damaging soil structure and polluting water environment, which is contrary to the current green and low-carbon development concept.

[0003] Existing biodegradable food packaging materials are mostly made from starch, polylactic acid, etc. as a single base material. However, these materials generally have defects such as weak mechanical properties, poor water and oil resistance, and degradation rate that is difficult to match the actual service life. They cannot meet the comprehensive requirements of food packaging for material stability and limit their large-scale application. Summary of the Invention

[0004] The purpose of this invention is to provide a biodegradable material for catering and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a biodegradable material for catering, wherein the biodegradable material is composed of the following raw materials in parts by weight:

[0006] 30-50 parts starch

[0007] 20-30 parts of polylactic acid

[0008] 10-20 parts plant fiber

[0009] 5-10 parts plasticizer

[0010] 2-5 parts of crosslinking agent

[0011] 3-6 parts of water-resistant agent

[0012] 1-3 parts degradation regulator

[0013] Antibacterial agent 0.5-2 parts.

[0014] Preferably, the specific mass fractions are as follows: 40 parts starch, 25 parts polylactic acid, 15 parts plant fiber, 8 parts plasticizer, 3 parts crosslinking agent, 4 parts water-resistant agent, 2 parts degradation regulator and 1 part antibacterial agent.

[0015] Preferably, the starch is one or a mixture of corn starch, tapioca starch, or sweet potato starch.

[0016] Preferably, the plant fiber is one or more of straw fiber, bamboo fiber, or bagasse fiber.

[0017] Preferably, the water-resistant agent is one or a mixture of methyl hydrogen silicone oil, paraffin emulsion, or chitosan.

[0018] Preferably, a method for preparing a biodegradable material for food service is as follows:

[0019] S1. Raw material pretreatment: Starch and plant fiber are pretreated and modified respectively to obtain pretreated starch and modified plant fiber; polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are dried respectively at 70-80℃ for 1-2 hours to remove moisture from the raw materials;

[0020] S2. Mixing: According to the weight ratio, add the pretreated starch, modified plant fiber, dried polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent into a high-speed mixer and mix for 30-40 minutes at a speed of 300-400 r / min and a temperature of 80-90℃ to obtain a mixture.

[0021] S3. Melt Blending: The mixture is fed into a twin-screw extruder for melt blending extrusion. The temperatures of each section of the twin-screw extruder are set as follows: feed section 120-130℃, compression section 140-150℃, homogenization section 150-160℃, and die head 160-170℃. The screw speed is 150-200 r / min to obtain the blend.

[0022] S4. Molding: The blend is fed into the molding machine and injection molded or calendered according to the required shape of the catering packaging product. The molding temperature is 150-160℃ and the molding pressure is 10-15MPa.

[0023] S5. Post-processing: Cool and shape the molded product at a temperature of 20-30℃ for 30-60 minutes. Then trim and inspect the product to obtain the finished biodegradable material for catering.

[0024] Preferably, in the raw material pretreatment, the starch pretreatment method is as follows: the starch is added to a 5-8% sodium hydroxide solution and soaked for 20-30 minutes at a soaking temperature of 40-50°C, then filtered, washed until neutral and dried; the plant fiber modification treatment is as follows: the plant fiber is soaked and modified with a 3-5% silane coupling agent KH-550 solution at a modification temperature of 60-70°C for 1-1.5 hours, and then filtered and dried to obtain modified plant fiber.

[0025] Preferably, the high-speed mixer operates at a speed of 350 r / min, a temperature of 85°C, and a mixing time of 30 min during the mixing process.

[0026] Preferably, the molding temperature in step S4 is 155°C and the molding pressure is 12 MPa.

[0027] Preferably, the cooling temperature in step S5 is 25°C and the cooling time is 40 minutes.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. This invention significantly improves the compatibility and interfacial bonding between raw materials by targeted pretreatment and modification of starch and plant fiber; at the same time, it optimizes the weight ratio of each component, so that the prepared biodegradable material has both excellent mechanical properties and water and oil resistance. In addition, the addition of degradation regulators can flexibly control the degradation rate of the material according to the actual use scenario, which not only ensures the stability of the material during its service life, but also enables it to degrade rapidly after disposal without causing environmental pollution. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] To achieve the above objectives, the present invention provides the following technical solution: a biodegradable material for catering, wherein the biodegradable material is composed of the following raw materials in parts by weight:

[0032] 30-50 parts starch

[0033] 20-30 parts of polylactic acid

[0034] 10-20 parts plant fiber

[0035] 5-10 parts plasticizer

[0036] 2-5 parts of crosslinking agent

[0037] 3-6 parts of water-resistant agent

[0038] 1-3 parts degradation regulator

[0039] Antibacterial agent 0.5-2 parts.

[0040] Example 1:

[0041] A method for preparing a biodegradable material for food service, the specific preparation method is as follows:

[0042] S1. Raw material pretreatment: Starch and plant fiber are pretreated and modified respectively to obtain pretreated starch and modified plant fiber; polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are dried separately at 70℃ for 1 hour to remove moisture from the raw materials;

[0043] S2. Mixing: According to the weight ratio, add the pretreated starch, modified plant fiber, dried polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent into a high-speed mixer and mix for 30 minutes at a speed of 300 r / min and a temperature of 80℃ to obtain a mixture.

[0044] S3. Melt Blending: The mixture is fed into a twin-screw extruder for melt blending extrusion. The temperatures of each section of the twin-screw extruder are set as follows: feed section 120℃, compression section 140℃, homogenization section 150℃, and die head 160℃. The screw speed is 150 r / min to obtain the blend.

[0045] S4. Molding: The blend is fed into the molding machine and injection molded or calendered according to the required shape of the catering packaging product. The molding temperature is 150℃ and the molding pressure is 10MPa.

[0046] S5. Post-processing: The molded product is cooled and shaped at a temperature of 20°C for 30 minutes. Then, it is trimmed and inspected to obtain the finished biodegradable material for catering.

[0047] Example 2:

[0048] A method for preparing a biodegradable material for food service, the specific preparation method is as follows:

[0049] S1. Raw material pretreatment: Starch and plant fiber are pretreated and modified respectively to obtain pretreated starch and modified plant fiber; polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are dried separately at 75℃ for 1.5h to remove moisture from the raw materials.

[0050] S2. Mixing: According to the weight ratio, pretreated starch, modified plant fiber, dried polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are added to a high-speed mixer and mixed for 35 minutes at a speed of 350 r / min and a temperature of 85℃ to obtain a mixture.

[0051] S3. Melt Blending: The mixture is fed into a twin-screw extruder for melt blending extrusion. The temperatures of each section of the twin-screw extruder are set as follows: feed section 125℃, compression section 145℃, homogenization section 155℃, and die head 165℃. The screw speed is 180 r / min to obtain the blend.

[0052] S4. Molding: The blend is fed into the molding machine and injection molded or calendered according to the required shape of the catering packaging product. The molding temperature is 155℃ and the molding pressure is 12MPa.

[0053] S5. Post-processing: The molded product is cooled and shaped at a temperature of 25°C for 40 minutes. Then, it is trimmed and inspected to obtain the finished biodegradable material for catering.

[0054] Example 3:

[0055] A method for preparing a biodegradable material for food service, the specific preparation method is as follows:

[0056] S1. Raw material pretreatment: Starch and plant fiber are pretreated and modified respectively to obtain pretreated starch and modified plant fiber; polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are dried separately at 80℃ for 2 hours to remove moisture from the raw materials;

[0057] S2. Mixing: According to the weight ratio, add the pretreated starch, modified plant fiber, dried polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent into a high-speed mixer and mix for 40 minutes at a speed of 400 r / min and a temperature of 90℃ to obtain a mixture.

[0058] S3. Melt Blending: The mixture is fed into a twin-screw extruder for melt blending extrusion. The temperatures of each section of the twin-screw extruder are set as follows: feed section 130℃, compression section 150℃, homogenization section 160℃, and die head 170℃. The screw speed is 200 r / min to obtain the blend.

[0059] S4. Molding: The blend is fed into the molding machine and injection molded or calendered according to the required shape of the catering packaging product. The molding temperature is 160℃ and the molding pressure is 15MPa.

[0060] S5. Post-processing: The molded product is cooled and shaped at a temperature of 30°C for 60 minutes. Then, it is trimmed and inspected to obtain the finished biodegradable material for catering.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A biodegradable material for food service, characterized in that: Its biodegradable material is composed of the following raw materials in parts by weight: 30-50 parts starch 20-30 parts of polylactic acid 10-20 parts plant fiber 5-10 parts plasticizer 2-5 parts of crosslinking agent 3-6 parts of water-resistant agent Degradation regulator 1-3 parts Antibacterial agent 0.5-2 parts.

2. The biodegradable material for catering use according to claim 1, characterized in that: The specific mass fractions are as follows: 40 parts starch, 25 parts polylactic acid, 15 parts plant fiber, 8 parts plasticizer, 3 parts crosslinking agent, 4 parts water-resistant agent, 2 parts degradation regulator and 1 part antibacterial agent.

3. The biodegradable material for catering use according to claim 1, characterized in that: The starch is one or more of corn starch, tapioca starch, or sweet potato starch.

4. The biodegradable material for catering use according to claim 1, characterized in that: The plant fiber is one or more of straw fiber, bamboo fiber, or bagasse fiber.

5. The biodegradable material for catering use according to claim 1, characterized in that: The water-resistant agent is one or more of methyl hydrogen silicone oil, paraffin emulsion, or chitosan.

6. A method for preparing a biodegradable material for food service, characterized in that: The specific preparation method is as follows: S1. Raw material pretreatment: Starch and plant fiber are pretreated and modified respectively to obtain pretreated starch and modified plant fiber; polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent are dried respectively at 70-80℃ for 1-2 hours to remove moisture from the raw materials; S2. Mixing: According to the weight ratio, add the pretreated starch, modified plant fiber, dried polylactic acid, plasticizer, crosslinking agent, water-resistant agent, degradation regulator and antibacterial agent into a high-speed mixer and mix for 30-40 minutes at a speed of 300-400 r / min and a temperature of 80-90℃ to obtain a mixture. S3. Melt Blending: The mixture is fed into a twin-screw extruder for melt blending extrusion. The temperatures of each section of the twin-screw extruder are set as follows: feed section 120-130℃, compression section 140-150℃, homogenization section 150-160℃, and die head 160-170℃. The screw speed is 150-200 r / min to obtain the blend. S4. Molding: The blend is fed into the molding machine and injection molded or calendered according to the required shape of the catering packaging product. The molding temperature is 150-160℃ and the molding pressure is 10-15MPa. S5. Post-processing: Cool and shape the molded product at a temperature of 20-30℃ for 30-60 minutes. Then trim and inspect the product to obtain the finished biodegradable material for catering.

7. The method for preparing a biodegradable material for catering according to claim 6, characterized in that: In the raw material pretreatment, the starch is pretreated by soaking it in a 5-8% sodium hydroxide solution for 20-30 minutes at a temperature of 40-50°C, followed by filtration, washing until neutral, and drying. The modification treatment of plant fibers is as follows: the plant fibers are soaked and modified with a 3-5% (w / w) solution of silane coupling agent KH-550, the modification temperature is 60-70℃, the modification time is 1-1.5h, and the modified plant fibers are obtained by filtration and drying after modification.

8. The method for preparing a biodegradable material for catering according to claim 6, characterized in that: During the mixing process, the high-speed mixer operates at a speed of 350 r / min, a temperature of 85°C, and a mixing time of 30 min.

9. A method for preparing a biodegradable material for catering according to claim 6, characterized in that: In step S4, the molding temperature is 155°C and the molding pressure is 12 MPa.

10. A method for preparing a biodegradable material for catering according to claim 6, characterized in that: In step S5, the cooling temperature is 25°C and the cooling time is 40 minutes.