High-barrier full-degradable meal box and preparation method thereof

Abstract

The invention discloses a preparation method of a high-barrier full-degradable lunch box, which is characterized by comprising the following steps: S1, preparing raw materials of a sheet: preparing materials according to an outer layer, a middle layer and an inner layer respectively; s2, sheet preparation: respectively pouring the raw materials of the outer layer, the middle layer and the inner layer into corresponding screw extruders for melt extrusion, and calendering the extruded materials to obtain an outer layer sheet, a middle layer sheet and an inner layer sheet; s3, the outer-layer sheet, the middle-layer sheet and the inner-layer sheet are subjected to plastic uptake forming through an injection molding machine, and an outer-layer meal box, a middle-layer meal box and an inner-layer meal box are obtained; s4, the outer-layer meal box, the middle-layer meal box and the inner-layer meal box are sequentially bonded through glue, and the formed meal box is obtained. The invention further discloses the high-barrier full-degradable meal box. Compared with the prior art, the problem that an existing meal box is difficult to degrade and recycle and causes serious white pollution to the environment can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lunch box preparation, and in particular to a high-barrier fully degradable lunch box and a preparation method thereof. Background Art

[0002] With the development of science and technology and social progress, plastics and their products are widely used in all aspects of life. While bringing convenience to human life, the "white pollution" problem caused by discarded plastic waste has also greatly damaged the environment. Biodegradable polymer materials made from biological and natural resources have become a research hotspot and development trend.

[0003] At present, the disposable lunch boxes, bowls, plates, cups and trays used in the Chinese market are all made of polystyrene (PS) as the material, which is extruded into sheets in a molten state and then formed by vacuum forming. Its disadvantage is that it is non-degradable, difficult to recycle, and causes serious white pollution to the environment. Summary of the invention

[0004] The purpose of the present invention is to provide a high-barrier fully degradable lunch box and a preparation method thereof in order to solve the problem that existing lunch boxes are difficult to degrade and recycle, causing serious white pollution to the environment.

[0005] To this end, on the one hand, the present invention provides a method for preparing a high-barrier fully degradable lunch box, which comprises the following steps:

[0006] S1: Sheet material preparation, including outer layer, middle layer and inner layer preparation;

[0007] S2: Sheet preparation, pouring the raw materials of the outer layer, the middle layer and the inner layer into the corresponding screw extruders for melt extrusion, and calendering the extruded materials to obtain the outer layer sheet, the middle layer sheet and the inner layer sheet;

[0008] S3: using an injection molding machine to perform vacuum forming of the outer layer sheet, the middle layer sheet and the inner layer sheet to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box;

[0009] S4: Adhere the outer lunch box, the middle lunch box and the inner lunch box in sequence using glue to obtain a formed lunch box.

[0010] As a further description of the above technical solution:

[0011] The outer layer raw material comprises the following components in parts by mass: 45-50 parts of polylactic acid, 40-55 parts of modified loofah, 5-10 parts of polycaprolactone, 0.5-1 parts of vinyl bisstearamide, 0.5-1 parts of paraffin oil, 1-3 parts of plasticizer and 1-5 parts of nucleating agent.

[0012] As a further description of the above technical solution:

[0013] The nucleating agent is a porous graphene / PEG-SA composite nucleating agent.

[0014] As a further description of the above technical solution:

[0015] The raw material of the inner layer is the same as that of the outer layer.

[0016] As a further description of the above technical solution:

[0017] The intermediate layer raw material comprises the following components in parts by mass: 80-90 parts of polyglycolic acid PGA; 2-20 parts of a filling reinforcing agent; 0.5-6 parts of a first nucleating agent and 1-15 parts of a temperature resistance regulator.

[0018] As a further description of the above technical solution:

[0019] The first nucleating agent is prepared from nano silicon dioxide, sodium benzoate and ethylene bisstearamide as raw materials.

[0020] As a further description of the above technical solution:

[0021] The filler reinforcing agent is a mixture of one or more selected from calcium carbonate, talc, barium sulfate, mica powder, kaolin, wollastonite, zeolite powder and diatomaceous earth.

[0022] As a further description of the above technical solution:

[0023] The temperature-resistant regulator is prepared from montmorillonite, aluminum dihydrogen phosphate and a surfactant as raw materials.

[0024] As a further description of the above technical solution:

[0025] The preparation method of the glue is as follows: certain weight portions of toluene, ethyl acetate, acrylic resin and carbon nanotubes are mixed, and then filtered and allowed to stand under a certain pressure to obtain the glue.

[0026] On the other hand, the present invention provides a high-barrier fully degradable lunch box, which is prepared by any one of the above-mentioned methods for preparing a high-barrier fully degradable lunch box.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] 1. In the present invention, the lunch box of the present invention comprises an outer layer, a middle layer and an inner layer. The outer layer, the middle layer and the inner layer are prepared separately and then bonded together by glue. When recycling, the inner layer, the outer layer and the middle layer can be torn apart for classified recycling, which is convenient for recycling and reuse.

[0029] 2. In the present invention, the outer layer and the inner layer of the invention are both prepared from polylactic acid and modified loofah, polylactic acid is an easily degradable material, and the modified loofah is prepared from dry loofah and is a natural degradable material. The use of polylactic acid and modified loofah can improve the degradation efficiency, reduce the amount of polylactic acid used, and reduce the cost; the porous graphene / PEG-SA composite nucleating agent uses low-molecular-weight PEG as a plasticizer to increase the gap between molecular chains and improve the mobility of the molecular chains. The porous graphene is used as a heterogeneous nucleation point. The porous graphene / PEG-SA composite nucleating agent is prepared under the action of ultrasonic oscillation coupled vacuum infusion in a controllable preparation device for organic composite phase change energy storage materials, and the crystallization performance of polylactic acid is improved through organic-inorganic interaction, thereby enhancing the heat resistance of polylactic acid.

[0030] 3. In the present invention, the intermediate layer material is added with a nucleating agent and a temperature-resistant regulator, so that the product made from the composition has good strength and temperature resistance even in the case of thin walls. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the specific embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0032] The preferred embodiments described below are for example only, and those skilled in the art may think of other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0033] In order to facilitate understanding of the technical solution of the present application, the following is a detailed description using different examples. In the following examples, various processes and methods not described in detail are conventional methods known in the art.

[0034] The present invention provides a method for preparing a high-barrier fully degradable lunch box, which comprises the following steps:

[0035] S1: Sheet material preparation, including outer layer, middle layer and inner layer preparation;

[0036] S2: Sheet preparation, pouring the raw materials of the outer layer, the middle layer and the inner layer into the corresponding screw extruders for melt extrusion, and calendering the extruded materials to obtain the outer layer sheet, the middle layer sheet and the inner layer sheet;

[0037] S3: using an injection molding machine to perform vacuum forming of the outer layer sheet, the middle layer sheet and the inner layer sheet to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box;

[0038] S4: Adhere the outer lunch box, the middle lunch box and the inner lunch box in sequence using glue to obtain a formed lunch box.

[0039] The outer layer raw material comprises the following components in parts by mass: 45-50 parts of polylactic acid, 40-55 parts of modified loofah, 5-10 parts of polycaprolactone, 0.5-1 parts of vinyl bisstearamide, 0.5-1 parts of paraffin oil, 1-3 parts of plasticizer and 1-5 parts of nucleating agent.

[0040] The preparation process of the modified loofah is as follows: the dry loofah is washed, dried and then crushed, the crushed dry loofah fiber is placed in a reaction bottle, NaOH solution and H2O2 solution are added to a reflux device for reflux treatment, then HCl solution is added, and the mother liquor is washed with hydrochloric acid until the pH value of the mother liquor is detected to be 7.0±0.5, and amino acid ester is added to continue the reflux reaction; the loofah is filtered, washed with pure water, and dried to obtain the modified loofah.

[0041] The nucleating agent is a porous graphene / PEG-SA composite nucleating agent. The preparation of the porous graphene / PEG-SA composite nucleating agent can refer to the existing patent CN201610623604.0.

[0042] The raw material of the inner layer is the same as that of the outer layer.

[0043] The intermediate layer raw material comprises the following components in parts by mass: 80-90 parts of polyglycolic acid PGA; 2-20 parts of a filling reinforcing agent; 0.5-6 parts of a first nucleating agent and 1-15 parts of a temperature resistance regulator.

[0044] The first nucleating agent is prepared from nano silicon dioxide, sodium benzoate and ethylene bisstearamide in a mass ratio of 0.3-3:0.1-1:0.1-1.

[0045] The filler reinforcing agent is a mixture of one or more selected from calcium carbonate, talc, barium sulfate, mica powder, kaolin, wollastonite, zeolite powder and diatomaceous earth, and the particle size is 10-15 μm.

[0046] The temperature-resistant regulator is prepared from montmorillonite, aluminum dihydrogen phosphate and a surfactant in a mass ratio of 7-10:0.7-1:0.1-0.2 as raw materials.

[0047] The preparation method of the glue is: toluene, ethyl acetate, acrylic resin, and carbon nanotubes are mixed in certain weight parts, and then filtered and allowed to stand under a certain pressure to obtain the glue. Can the glue layer improve the tensile strength between the outer layer, the middle layer, and the inner layer, and is not easy to bulge and crack?

[0048] A high-barrier fully degradable lunch box is prepared by any one of the above-mentioned methods for preparing a high-barrier fully degradable lunch box.

[0049] Embodiment 1:

[0050] A high-barrier fully degradable lunch box, comprising an outer layer, a middle layer and an inner layer. The outer layer and the inner layer are made of the same raw materials. By weight, the outer layer raw materials include: 45 parts of polylactic acid, 40 parts of modified loofah, 5 parts of polycaprolactone, 0.5 parts of vinyl bisstearamide, 0.5 parts of paraffin oil, 1 part of plasticizer and 1 part of nucleating agent; vinyl bisstearamide, paraffin oil, plasticizer and nucleating agent are all degradable additives;

[0051] The intermediate layer raw materials include: 80 parts of polyglycolic acid PGA; 2 parts of filler reinforcing agent; 0.5 parts of first nucleating agent and 1 part of temperature resistance regulator;

[0052] The raw materials of the outer layer, the middle layer and the inner layer are respectively poured into corresponding screw extruders for melt extrusion, and the extruded materials are calendered to obtain outer layer sheets, middle layer sheets and inner layer sheets;

[0053] The outer layer sheet, the middle layer sheet and the inner layer sheet are formed by vacuum forming using an injection molding machine to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box;

[0054] The outer layer lunch box, the middle layer lunch box and the inner layer lunch box are sequentially bonded with glue to obtain a formed lunch box.

[0055] Embodiment 2:

[0056] A high-barrier fully degradable lunch box, comprising an outer layer, a middle layer and an inner layer, wherein the outer layer and the inner layer are made of the same raw materials, and the outer layer raw materials include, by weight: 46 parts of polylactic acid, 45 parts of modified loofah, 6 parts of polycaprolactone, 0.6 parts of vinyl bisstearamide, 0.6 parts of paraffin oil, 2 parts of plasticizer and 3 parts of nucleating agent;

[0057] The intermediate layer raw materials include: 85 parts of polyglycolic acid PGA; 10 parts of filler reinforcing agent; 3 parts of first nucleating agent and 4 parts of temperature-resistant regulator;

[0058] The raw materials of the outer layer, the middle layer and the inner layer are respectively poured into corresponding screw extruders for melt extrusion, and the extruded materials are calendered to obtain outer layer sheets, middle layer sheets and inner layer sheets;

[0059] The outer layer sheet, the middle layer sheet and the inner layer sheet are formed by vacuum forming using an injection molding machine to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box;

[0060] The outer layer lunch box, the middle layer lunch box and the inner layer lunch box are sequentially bonded with glue to obtain a formed lunch box.

[0061] Embodiment three:

[0062] A high-barrier fully degradable lunch box, comprising an outer layer, a middle layer and an inner layer, wherein the outer layer and the inner layer are made of the same raw materials, and the outer layer raw materials include, by weight, 50 parts of polylactic acid, 55 parts of modified loofah, 10 parts of polycaprolactone, 1 part of vinyl bisstearamide, 1 part of paraffin oil, 3 parts of plasticizer and 5 parts of nucleating agent;

[0063] The intermediate layer raw materials include: 90 parts of polyglycolic acid PGA; 20 parts of filler reinforcing agent; 6 parts of first nucleating agent and 15 parts of temperature resistance regulator;

[0064] The raw materials of the outer layer, the middle layer and the inner layer are respectively poured into corresponding screw extruders for melt extrusion, and the extruded materials are calendered to obtain outer layer sheets, middle layer sheets and inner layer sheets;

[0065] The outer layer sheet, the middle layer sheet and the inner layer sheet are formed by vacuum forming using an injection molding machine to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box;

[0066] The outer layer lunch box, the middle layer lunch box and the inner layer lunch box are sequentially bonded with glue to obtain a formed lunch box.

[0067] Comparative Example 1:

[0068] Compared with Example 1, the outer layer raw material in Comparative Example 1 does not contain modified loofah, and the remaining components and preparation method are the same as those in Example 1.

[0069] Comparative Example 2:

[0070] Compared with Example 1, the glue in Comparative Example 1 does not contain carbon nanotubes, and the remaining components and preparation method are the same as those in Example 1.

[0071] Product effect testing

[0072] The lunch boxes prepared in Examples 1-3 and Comparative Example 1 were mixed with soil in which soybeans had been grown in a mass ratio of 1:2, and then placed under conditions of a temperature of 37°C, a relative humidity of 50%, an oxygen volume concentration of 20%, and natural light for 1 month, 2 months, 3 months, 4 months, 5 months, and 6 months, and the degradation rate of the lunch boxes corresponding to each month was weighed respectively (for example, the degradation rate at 3 months (%) = (initial mass of the lunch box - the remaining mass of the lunch box at 3 months) / initial mass of the lunch box * 100%). The results are shown in Table 1.

[0073]

[0074]

[0075] It can be seen from Table 1 that the degradation rate of the lunch boxes prepared in Examples 1-3 of the present invention is significantly better than the degradation rate of the lunch boxes prepared without adding the modified loofah.

[0076] The lunch boxes prepared in Example 1 and Comparative Example 1 were left standing at room temperature for 10 days, and then their tear strength was tested under the same conditions (test standard is GB / T1040.3). The results are shown in Table 2.

[0077] Tear strength (N / 15mm) Example 1 120 Comparative Example 1 109

[0078] It can be seen from Table 2 that compared with Comparative Example 1, the glue layer of Comparative Example 1 does not contain carbon nanotubes, and the prepared lunch box is easy to tear open, and the performance is poor.

[0079] The above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A method for preparing a high-barrier fully degradable lunch box, characterized in that: The following steps are involved: S1: Sheet material preparation, including outer layer, middle layer and inner layer preparation; S2: Sheet preparation, pouring the raw materials of the outer layer, the middle layer and the inner layer into the corresponding screw extruders for melt extrusion, and calendering the extruded materials to obtain the outer layer sheet, the middle layer sheet and the inner layer sheet; S3: using an injection molding machine to perform vacuum forming of the outer layer sheet, the middle layer sheet and the inner layer sheet to obtain an outer layer lunch box, a middle layer lunch box and an inner layer lunch box; S4: Adhere the outer lunch box, the middle lunch box and the inner lunch box in sequence using glue to obtain a formed lunch box.

2. The method for preparing a high barrier and fully degradable lunch box according to claim 1, characterized in that: The outer layer raw material comprises the following components in parts by mass: 45-50 parts of polylactic acid, 40-55 parts of modified loofah, 5-10 parts of polycaprolactone, 0.5-1 parts of vinyl bisstearamide, 0.5-1 parts of paraffin oil, 1-3 parts of plasticizer and 1-5 parts of nucleating agent.

3. The method for preparing a high barrier fully degradable lunch box according to claim 2, characterized in that: The nucleating agent is a porous graphene / PEG-SA composite nucleating agent.

4. The method for preparing a high barrier and fully degradable lunch box according to claim 2, characterized in that: The raw material of the inner layer is the same as that of the outer layer.

5. The method for preparing a high barrier and fully degradable lunch box according to claim 1, characterized in that: The intermediate layer raw material comprises the following components in parts by mass: 80-90 parts of polyglycolic acid PGA; 2-20 parts of a filling reinforcing agent; 0.5-6 parts of a first nucleating agent and 1-15 parts of a temperature resistance regulator.

6. The method for preparing a high barrier and fully degradable lunch box according to claim 5, characterized in that: The first nucleating agent is prepared from nano silicon dioxide, sodium benzoate and ethylene bisstearamide as raw materials.

7. The method for preparing a high barrier and fully degradable lunch box according to claim 5, characterized in that: The filler reinforcing agent is a mixture of one or more selected from calcium carbonate, talc, barium sulfate, mica powder, kaolin, wollastonite, zeolite powder and diatomaceous earth.

8. The method for preparing a high barrier and fully degradable lunch box according to claim 5, characterized in that: The temperature-resistant regulator is prepared from montmorillonite, aluminum dihydrogen phosphate and a surfactant as raw materials.

9. The method for preparing a high barrier and fully degradable lunch box according to claim 1, characterized in that: The preparation method of the glue is as follows: certain weight portions of toluene, ethyl acetate, acrylic resin and carbon nanotubes are mixed, and then filtered and allowed to stand under a certain pressure to obtain the glue.

10. A high barrier fully degradable lunch box, characterized in that: The high-barrier fully degradable lunch box is prepared by the method for preparing a high-barrier fully degradable lunch box according to any one of claims 1-9.

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