Degradable lunch box and production process thereof

Abstract

The present invention discloses a degradable lunch box and its production process. The box is made from the following ingredients: bamboo powder, polylactic acid resin, stearate, a composite modified filler, and starch. The degradable lunch box produced by the present invention is environmentally friendly and can undergo biochemical reactions in the natural environment and under the action of enzymes, ultimately degrading into carbon dioxide and water, thereby reducing environmental pollution. The main raw material of the present invention is polylactic acid, which is derived from renewable resources such as corn starch and has good biodegradability.

Description

Technical Field

[0001] The invention belongs to the technical field of degradable materials, in particular to a degradable lunch box and a production process thereof. Background Art

[0002] With the rise of the fast food industry, the use of fast food packaging boxes is increasing. Due to the large-scale use of plastic lunch boxes, after they are discarded, white pollution will become increasingly serious, endangering the human living environment. Therefore, the development of degradable materials is in line with the needs of ecological development and has a huge market demand.

[0003] Degradable tableware refers to tableware that can undergo biochemical reactions under the action of microorganisms (bacteria, mold, algae) and enzymes in the natural environment, causing changes from mold in appearance to internal quality, and ultimately forming carbon dioxide and water.

[0004] In the prior art, lunch boxes are made by processing polylactic acid materials. Due to the excellent biodegradability of polylactic acid materials, they have been widely used in the field of biodegradable materials. However, lunch boxes made from pure polylactic acid materials have relatively general mechanical properties, especially relatively poor impact strength, which limits their application.

[0005] Therefore, the present invention solves the corresponding problems by providing a degradable lunch box. Summary of the Invention

[0006] The purpose of the present invention is to provide a degradable lunch box to solve the deficiencies in the prior art.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A degradable lunch box comprises the following ingredients in parts by weight: 20-30 parts of bamboo powder, 60-75 parts of polylactic acid resin, 1-2 parts of stearate, 10-15 parts of composite modified filler, and 12-16 parts of starch.

[0009] As a further technical solution: the preparation method of the composite modified filler is:

[0010] First, the bentonite is calcined to obtain calcined bentonite;

[0011] Add polybutylene succinate, calcined bentonite and coupling agent to a blender in sequence, and mix and stir for 40 minutes to obtain a uniform mixture;

[0012] The uniform mixture obtained above is added to an internal mixer for internal mixing. After the internal mixing is completed, the mixture is discharged to obtain a composite modified filler.

[0013] As a further technical solution: the preparation method of calcined bentonite is:

[0014] Bentonite and nitric acid solution were mixed in a mass ratio of 1:5, heated to 80°C, stirred for 40 minutes, then centrifuged, filtered, washed to neutrality, and dried to obtain;

[0015] Wherein, the mass fraction of nitric acid solution is 5%;

[0016] The stirring speed is 300 r / min;

[0017] The centrifugal speed was 8000 r / min and the centrifugal time was 15 min;

[0018] The drying temperature was 80°C and the drying time was 2 hours.

[0019] As a further technical solution: the mass ratio of the polybutylene succinate, calcined bentonite and coupling agent is 10-12:20-25:1-1.4;

[0020] The coupling agent is an organic silane coupling agent;

[0021] The organic silane coupling agent is vinyltrimethoxysilane.

[0022] As a further technical solution: the mixing process parameters are:

[0023] The mixing temperature is 180°C, the mixing speed is 75r / min, and the mixing time is 40-50min.

[0024] As a further technical solution: the stearate is calcium stearate.

[0025] As a further technical solution: the starch is soybean starch;

[0026] The soybean starch is subjected to a modification treatment:

[0027] The soybean starch is added to the nitric acid solution, the temperature is adjusted to 90°C, the mixture is kept warm and stirred for 2 hours, then adjusted to neutrality, and dried to a moisture content of less than 5% to obtain;

[0028] The mixing ratio of the soybean starch and nitric acid solution is 30g:120mL.

[0029] A production process for a degradable lunch box comprises the following steps:

[0030] (1) Preparation of materials: Weigh bamboo powder, polylactic acid resin, stearate, composite modified filler, and starch according to their respective weight parts;

[0031] (2) Mixing: Add each component to a high-speed mixer in sequence and mix the raw materials evenly to obtain a mixed raw material;

[0032] (3) Banburying: Add the mixed raw materials to the banbury mixer and knead them to obtain the banbury rubber compound;

[0033] (4) Mixing: adding the mixed rubber material to the open mixer and mixing it to obtain a mixed material;

[0034] (5) Molding: The mixed material is added to an extruder for plasticization, and then pressed into shape in a mold, and cooled to room temperature to obtain a degradable lunch box.

[0035] As a further technical solution: the mixing time in the high-speed mixer in step (2) is 40 minutes;

[0036] The temperature of the banburying in step (3) is 155° C. and the time is 25 min.

[0037] As a further technical solution: in step (4), the mixing temperature is 188° C. and the mixing time is 30 min;

[0038] In step (5), the mold temperature is 135° C., the pressing pressure is 12 MPa, and the pressing time is 50 s.

[0039] Beneficial effects:

[0040] characteristic:

[0041] The degradable lunch box prepared by the present invention is an environmentally friendly lunch box that can undergo biochemical reactions under the action of a natural environment and enzymes and eventually degrade into carbon dioxide and water, thereby reducing pollution to the environment.

[0042] The main raw material of the present invention is polylactic acid, which is derived from renewable resources such as corn starch and has good biodegradability.

[0043] Compared with traditional plastic lunch boxes, the biodegradable lunch boxes prepared by the present invention can decompose faster in the natural environment, reducing long-term pollution to the environment; they are made of non-toxic and harmless raw materials, comply with national food hygiene standards, and are safer and more reliable to use; they can be made into various shapes and specifications according to different needs to meet the usage requirements in different scenarios.

[0044] In order to improve the mechanical properties of the degradable lunch box prepared by the present invention, the present invention introduces the prepared composite modified filler to promote the crystallization of polylactic acid, thereby improving its heat resistance and impact resistance. At the same time, the treated bentonite can better combine with the matrix PLA resin, thereby increasing the heat deformation temperature of the degradable lunch box prepared by the present invention and improving the impact strength.

[0045] The toughness of the degradable lunch box prepared by the present invention is enhanced by subjecting soybean starch to a denaturing treatment and then forming an interpenetrating network structure or a eutectic structure with polylactic acid.

[0046] By introducing bamboo powder and combining it with a composite modified filler, the hardness and strength of the degradable lunch box prepared by the present invention can be improved, making it more suitable for occasions that need to withstand certain pressure and wear.

[0047] The introduction of treated soybean starch, combined with the effect of modified composite fillers, significantly improves the processing fluidity of the material, which is crucial for the processing and molding process of the degradable lunch box prepared by the present invention and helps to improve production efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A flow chart for preparing a biodegradable lunch box. DETAILED DESCRIPTION

[0049] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0050] The following are specific embodiments

[0051] Example 1

[0052] A production process for a degradable lunch box comprises the following steps:

[0053] (1) Material preparation: weigh out the following materials in parts by weight: 20 parts of bamboo powder, 60 parts of polylactic acid resin, 1 part of stearate, 10 parts of composite modified filler, and 12 parts of starch.

[0054] The preparation method of the composite modified filler is as follows:

[0055] First, the bentonite is calcined to obtain calcined bentonite;

[0056] Add polybutylene succinate, calcined bentonite and coupling agent to a blender in sequence, and mix and stir for 40 minutes to obtain a uniform mixture;

[0057] The uniform mixture obtained above is added to an internal mixer for internal mixing. After the internal mixing is completed, the mixture is discharged to obtain a composite modified filler.

[0058] The preparation method of calcined bentonite is:

[0059] Bentonite and nitric acid solution were mixed in a mass ratio of 1:5, heated to 80°C, stirred for 40 minutes, then centrifuged, filtered, washed to neutrality, and dried to obtain;

[0060] Wherein, the mass fraction of nitric acid solution is 5%;

[0061] The stirring speed is 300 r / min;

[0062] The centrifugal speed was 8000 r / min and the centrifugal time was 15 min;

[0063] The drying temperature was 80°C and the drying time was 2 hours.

[0064] The mass ratio of polybutylene succinate, calcined bentonite and coupling agent is 10:20:1;

[0065] The coupling agent is an organic silane coupling agent;

[0066] The organic silane coupling agent is vinyltrimethoxysilane.

[0067] The mixing process parameters are:

[0068] The mixing temperature is 180°C, the mixing speed is 75 r / min, and the mixing time is 40 min.

[0069] Stearate is calcium stearate.

[0070] The starch is soybean starch;

[0071] The soybean starch is subjected to a modification treatment:

[0072] Soybean starch was added to the nitric acid solution, the temperature was adjusted to 90°C, and the mixture was stirred for 2 hours. Then the mixture was adjusted to neutral and dried to a moisture content of less than 5% to obtain:

[0073] The mixing ratio of the soybean starch and nitric acid solution is 30g:120mL.

[0074] (2) Mixing: Add each component to a high-speed mixer in sequence and mix the raw materials evenly to obtain a mixed raw material; the mixing time in the high-speed mixer is 40 minutes;

[0075] (3) Internal mixing: Add the mixed raw materials into an internal mixer and mix and knead them to obtain an internal mixing rubber compound; the internal mixing temperature is 155°C and the time is 25 minutes.

[0076] (4) Mixing: Add the mixed rubber material to the open mixer and mix it to obtain a mixed material; the mixing temperature is 188°C and the mixing time is 30 minutes;

[0077] (5) Molding: The mixed material is added to the extruder for plasticization, and then pressed into shape in the mold material mouth, and cooled to room temperature to obtain a degradable lunch box; the mold temperature is 135°C, the pressing pressure is 12 MPa, and the pressing time is 50 s.

[0078] Example 2

[0079] A production process for a degradable lunch box comprises the following steps:

[0080] (1) Preparation of materials: Weigh out the following materials in parts by weight: 24 parts of bamboo powder, 66 parts of polylactic acid resin, 1.5 parts of stearate, 12 parts of composite modified filler, and 15 parts of starch.

[0081] The preparation method of the composite modified filler is as follows:

[0082] First, the bentonite is calcined to obtain calcined bentonite;

[0083] Add polybutylene succinate, calcined bentonite and coupling agent to a blender in sequence, and mix and stir for 40 minutes to obtain a uniform mixture;

[0084] The uniform mixture obtained above is added to an internal mixer for internal mixing. After the internal mixing is completed, the mixture is discharged to obtain a composite modified filler.

[0085] The preparation method of calcined bentonite is:

[0086] Bentonite and nitric acid solution were mixed in a mass ratio of 1:5, heated to 80°C, stirred for 40 minutes, then centrifuged, filtered, washed to neutrality, and dried to obtain;

[0087] Wherein, the mass fraction of nitric acid solution is 5%;

[0088] The stirring speed is 300 r / min;

[0089] The centrifugal speed was 8000 r / min and the centrifugal time was 15 min;

[0090] The drying temperature is 80°C and the drying time is 2 hours.

[0091] The mass ratio of polybutylene succinate, calcined bentonite and coupling agent is 11:20:1.2;

[0092] The coupling agent is an organic silane coupling agent;

[0093] The organic silane coupling agent is vinyltrimethoxysilane.

[0094] The mixing process parameters are:

[0095] The mixing temperature is 180°C, the mixing speed is 75 r / min, and the mixing time is 45 min.

[0096] Stearate is calcium stearate.

[0097] The starch is soybean starch;

[0098] The soybean starch is subjected to a modification treatment:

[0099] The soybean starch is added to the nitric acid solution, the temperature is adjusted to 90°C, the mixture is kept warm and stirred for 2 hours, then adjusted to neutrality, and dried to a moisture content of less than 5% to obtain;

[0100] The mixing ratio of the soybean starch and nitric acid solution is 30g:120mL.

[0101] (2) Mixing: Add each component to a high-speed mixer in sequence and mix the raw materials evenly to obtain a mixed raw material; the mixing time in the high-speed mixer is 40 minutes;

[0102] (3) Internal mixing: Add the mixed raw materials into an internal mixer and mix and knead them to obtain an internal mixing rubber compound; the internal mixing temperature is 155°C and the time is 25 minutes.

[0103] (4) Mixing: Add the mixed rubber material to the open mixer and mix it to obtain a mixed material; the mixing temperature is 188°C and the mixing time is 30 minutes;

[0104] (5) Molding: The mixed material is added to the extruder for plasticization, and then pressed into shape in the mold material mouth, and cooled to room temperature to obtain a degradable lunch box; the mold temperature is 135°C, the pressing pressure is 12 MPa, and the pressing time is 50 s.

[0105] Example 3

[0106] A production process for a degradable lunch box comprises the following steps:

[0107] (1) Preparation of materials: Weigh out the following materials in parts by weight: 30 parts of bamboo powder, 75 parts of polylactic acid resin, 2 parts of stearate, 15 parts of composite modified filler, and 16 parts of starch.

[0108] The preparation method of the composite modified filler is as follows:

[0109] First, the bentonite is calcined to obtain calcined bentonite;

[0110] Add polybutylene succinate, calcined bentonite and coupling agent to a blender in sequence, and mix and stir for 40 minutes to obtain a uniform mixture;

[0111] The uniform mixture obtained above is added to an internal mixer for internal mixing. After the internal mixing is completed, the mixture is discharged to obtain a composite modified filler.

[0112] The preparation method of calcined bentonite is:

[0113] Bentonite and nitric acid solution were mixed in a mass ratio of 1:5, heated to 80°C, stirred for 40 minutes, then centrifuged, filtered, washed to neutrality, and dried to obtain;

[0114] Wherein, the mass fraction of nitric acid solution is 5%;

[0115] The stirring speed is 300 r / min;

[0116] The centrifugal speed was 8000 r / min and the centrifugal time was 15 min;

[0117] The drying temperature is 80°C and the drying time is 2 hours.

[0118] The mass ratio of polybutylene succinate, calcined bentonite and coupling agent is 12:25:1.4;

[0119] The coupling agent is an organic silane coupling agent;

[0120] The organic silane coupling agent is vinyltrimethoxysilane.

[0121] The mixing process parameters are:

[0122] The mixing temperature is 180°C, the mixing speed is 75r / min, and the mixing time is 40-50min.

[0123] Stearate is calcium stearate.

[0124] The starch is soybean starch;

[0125] The soybean starch is subjected to a modification treatment:

[0126] The soybean starch is added to the nitric acid solution, the temperature is adjusted to 90°C, the mixture is kept warm and stirred for 2 hours, then adjusted to neutrality, and dried to a moisture content of less than 5% to obtain;

[0127] The mixing ratio of the soybean starch and nitric acid solution is 30g:120mL.

[0128] (2) Mixing: Add each component to a high-speed mixer in sequence and mix the raw materials evenly to obtain a mixed raw material; the mixing time in the high-speed mixer is 40 minutes;

[0129] (3) Internal mixing: Add the mixed raw materials into an internal mixer and mix and knead them to obtain an internal mixing rubber compound; the internal mixing temperature is 155°C and the time is 25 minutes.

[0130] (4) Mixing: Add the mixed rubber material to the open mixer and mix it to obtain a mixed material; the mixing temperature is 188°C and the mixing time is 30 minutes;

[0131] (5) Molding: The mixed material is added to the extruder for plasticization, and then pressed into shape in the mold material mouth, and cooled to room temperature to obtain a degradable lunch box; the mold temperature is 135°C, the pressing pressure is 12 MPa, and the pressing time is 50 s.

[0132] Comparative Example 1:

[0133] On the basis of the technical solution of Example 1, the composite modified filler was replaced with an equal amount of bentonite, and the rest of the technical solutions remained unchanged.

[0134] Comparative Example 2:

[0135] Based on the technical solution of Example 1, soybean starch is replaced by corn starch, and the rest of the technical solutions remain unchanged.

[0136] Comparative Example 3:

[0137] Based on the technical solution of Example 1, the soybean starch is not modified, and the rest of the technical solutions remain unchanged.

[0138] test:

[0139] The samples of the embodiment were tested. The raw materials of the embodiment and comparative example samples were made into the required test specimens in a standard mold using a flat plate vulcanizer at 170°C and tested:

[0140] Notched impact strength test, refer to GB / T1843-2008, test 5 times each, and take the average value:

[0141] Table 1

[0142] Impact strength J / m Example 1 885 Example 2 893 Example 3 862 Comparative Example 1 761 Comparative Example 2 825 Comparative Example 3 801

[0143] It can be seen from Table 1 that the degradable lunch box prepared by the present invention has higher impact resistance.

[0144] The tensile strength of the samples of the embodiment and the comparative example was tested with reference to GB / T1040.-2018, each test was repeated 5 times, and the average value was taken:

[0145] Table 2

[0146]

[0147]

[0148] As can be seen from Table 2, the degradable lunch box prepared by the present invention has excellent tensile properties.

[0149] Degradation performance tests were performed on the examples and comparative examples:

[0150] Equal amounts of the example and comparative example samples were subjected to degradation tests in 5 mL of 0.1 M Tris-HCl buffer, where the concentration of proteinase K in the buffer was 0.15 mg / mL. The degradation tests were carried out in a vacuum oven at 50°C. After 60 hours, the samples were removed, cleaned, dried, and weighed, and the weight loss rate was calculated:

[0151] Table 3

[0152] Weight loss rate% Example 1 88.57 Example 2 89.03 Example 3 88.26 Comparative Example 1 82.79 Comparative Example 2 86.72 Comparative Example 3 85.08

[0153] As can be seen from Table 3, the degradable lunch box prepared by the present invention has excellent degradability.

[0154] The above description is only a preferred embodiment of the present invention, but the scope of implementation of the present invention is not limited to the embodiment shown. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description, should be within the scope of protection of the present invention.

Claims

1. A degradable lunch box, characterized in that: The composition comprises the following ingredients by weight: 20-30 parts of bamboo powder, 60-75 parts of polylactic acid resin, 1-2 parts of stearate, 10-15 parts of composite modified filler, and 12-16 parts of starch; The preparation method of the composite modified filler is as follows: First, the bentonite is calcined to obtain calcined bentonite; Add polybutylene succinate, calcined bentonite and coupling agent to a blender in sequence, and mix and stir for 40 minutes to obtain a uniform mixture; The uniform mixture obtained above is added to an internal mixer for internal mixing. After the internal mixing is completed, the material is discharged to obtain a composite modified filler; The starch is soybean starch; The soybean starch is subjected to a modification treatment: The soybean starch is added to the nitric acid solution, the temperature is adjusted to 90°C, the mixture is kept warm and stirred for 2 hours, then adjusted to neutrality, and dried to a moisture content of less than 5% to obtain; The mixing ratio of the soybean starch and nitric acid solution is 30g:120mL; The calcined bentonite preparation method is: Bentonite and nitric acid solution were mixed in a mass ratio of 1:5, heated to 80°C, stirred for 40 minutes, then centrifuged, filtered, washed until neutral, and dried to obtain; Among them, the mass fraction of nitric acid solution is 5%; The stirring speed is 300 r / min; The centrifugal speed was 8000 r / min and the centrifugal time was 15 min; The drying temperature was 80°C and the drying time was 2 hours.

2. The degradable lunch box according to claim 1, characterized in that: The mass ratio of the polybutylene succinate, calcined bentonite and coupling agent is 10-12:20-25:1-1.4; The coupling agent is an organic silane coupling agent; The organic silane coupling agent is vinyltrimethoxysilane.

3. The degradable lunch box according to claim 1, characterized in that: The banburying process parameters are: The mixing temperature is 180°C, the mixing speed is 75r / min, and the mixing time is 40-50min.

4. The degradable lunch box according to claim 1, characterized in that: The stearate is calcium stearate.

5. The production process of a degradable lunch box according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Preparation of materials: Weigh bamboo powder, polylactic acid resin, stearate, composite modified filler, and starch according to their respective weight parts; (2) Mixing: Add each component to a high-speed mixer in sequence and mix the raw materials evenly to obtain a mixed raw material; (3) Mixing: Add the mixed raw materials into the internal mixer and mix them to obtain the internal mixing rubber; (4) Mixing: Add the mixed rubber material to the open mixer for mixing to obtain a mixed material; (5) Molding: The mixed material is added to the extruder for plasticization, and then pressed into shape in the mold material mouth, and cooled to room temperature to obtain a degradable lunch box.

6. The production process of a degradable lunch box according to claim 5, characterized in that: The mixing time in the high-speed mixer in step (2) is 40 minutes; The mixing temperature in step (3) is 155°C and the mixing time is 25 minutes.

7. The production process of a degradable lunch box according to claim 5, characterized in that: The mixing temperature in step (4) is 188°C and the mixing time is 30 min; In step (5), the mold temperature is 135°C, the pressing pressure is 12 MPa, and the pressing time is 50 s.

Images