Biodegradable resin composition and molded body
Patent Information
- Application Number
- CN202180086318.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2020-12-25
- Filing Date
- 2021-12-24
- Publication Date
- 2026-09-18
- Estimated Expiration
- 2041-12-24
AI Technical Summary
[0013] According to this disclosure, a biodegradable resin composition and a molded article with a faster decomposition rate than in the past can be obtained.
Smart Images
Figure CN116635483B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to biodegradable resin compositions and molded articles. Background Technology
[0002] In recent years, environmental pollution caused by the disposal of packaging materials and other materials made from resins has become a concern, and technologies for using biodegradable resins in packaging materials are under development. Furthermore, in order to use biodegradable resins in packaging materials, additives are used to adjust the decomposition rate while maintaining the mechanical strength of the resin molded product, so that it can be decomposed by microorganisms or the like after disposal (e.g., Patent Document 1).
[0003] Existing technical documents
[0004] Patent documents
[0005] Patent Document 1: Japanese Patent No. 3646193 Summary of the Invention
[0006] The problem that the invention aims to solve
[0007] However, the decomposition rate of conventional biodegradable resins is insufficient depending on their intended use. In particular, when biodegradable resins are used in lunch containers, agricultural / horticultural materials, etc., they are often difficult to reuse or recycle due to food residue or soil contamination, thus becoming waste. A faster decomposition rate after disposal is desired.
[0008] This disclosure was made in view of the following problem, and its purpose is to provide a biodegradable resin composition and a molded article having a fast decomposition rate.
[0009] Methods for solving problems
[0010] To address the aforementioned issues, one aspect of the biodegradable resin composition disclosed herein is characterized in that it is a water-retaining biodegradable resin composition.
[0011] In addition, one aspect of the molded article disclosed herein is characterized in that it is formed from the aforementioned biodegradable resin composition.
[0012] The effects of the invention
[0013] According to this disclosure, a biodegradable resin composition and a molded article with a faster decomposition rate than in the past can be obtained. Attached Figure Description
[0014] [ Figure 1 [A graph showing the test results of the accelerated degradation test of Example 1.]
[0015] [ Figure 2A The graph shows the molecular weight determination results before and after the accelerated degradation test of Example 1.
[0016] [ Figure 2B The graph shows the molecular weight determination results before and after the accelerated degradation test of Example 1-1.
[0017] [ Figure 2C The graph shows the molecular weight determination results before and after the accelerated degradation test of Examples 1-2.
[0018] [ Figure 2D [This is a graph showing the molecular weight determination results before and after the accelerated degradation test of Examples 1-3.]
[0019] [ Figure 2E [This is a graph showing the molecular weight determination results before and after the accelerated degradation test of Examples 1-4.]
[0020] [ Figure 2F [A graph showing the molecular weight determination results before and after the accelerated degradation test of Comparative Example 1-1.]
[0021] [ Figure 3 [A graph showing the test results of the accelerated degradation test in Example 2.]
[0022] [ Figure 4 [A graph showing the test results of the weather resistance test of Example 2.]
[0023] [ Figure 5A Scanning electron microscope images obtained for observing the surface of the test pieces before each test in Example 2-1.
[0024] [ Figure 5B [Scanning electron microscope image obtained for observing the surface of the test piece after the accelerated degradation test of Example 2-1.]
[0025] [ Figure 5C [Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Example 2-1.]
[0026] [ Figure 6A Scanning electron microscope images obtained for observing the surface of the test pieces before each test in Examples 2-2.
[0027] [ Figure 6B [Scanning electron microscope image obtained for observing the surface of the test piece after the accelerated degradation test of Example 2-2.]
[0028] [ Figure 6C[Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Example 2-2.]
[0029] [ Figure 7A Scanning electron microscope images obtained for observing the surface of the test pieces before each test in Comparative Example 2-1.
[0030] [ Figure 7B [Scanning electron microscope image obtained to observe the surface of the test piece after the accelerated degradation test of Comparative Example 2-1.]
[0031] [ Figure 7C [Scanning electron microscope image obtained to observe the surface of the test piece after the weathering test of Comparative Example 2-1.]
[0032] [ Figure 8 [A graph showing the molecular weight determination results of the biodegradable resin composition in the test piece before and after the accelerated degradation test of Example 2.]
[0033] [ Figure 9A [A graph showing the molecular weight determination results before the weathering test of Example 2.]
[0034] [ Figure 9B The graph shows the molecular weight determination results before and after the weather resistance test of Example 2-1.
[0035] [ Figure 9C The graph shows the molecular weight determination results before and after the weather resistance test of Example 2-2.
[0036] [ Figure 9D [A graph showing the molecular weight determination results before and after the weathering test of Comparative Example 2-1.]
[0037] [ Figure 10A [A graph showing the molecular weight determination results before the weathering test of Example 3.]
[0038] [ Figure 10B [A graph showing the molecular weight determination results before and after the weather resistance test of Example 3-2.]
[0039] [ Figure 10C The graph shows the molecular weight determination results before and after the weather resistance test of Examples 3-3.
[0040] [ Figure 10D The graph shows the molecular weight determination results before and after the weather resistance test of Examples 3-4.
[0041] [ Figure 10E [A graph showing the molecular weight determination results before and after the weathering test of Comparative Example 3-2.]
[0042] [ Figure 11A [Scanning electron microscope image obtained for observing the surface of the test piece before the weathering test of Example 3-2.]
[0043] [ Figure 11B [Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Example 3-2.]
[0044] [ Figure 12A [Scanning electron microscope image obtained for observing the surface of the test piece before the weathering test of Example 3-3.]
[0045] [ Figure 12B [Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Example 3-3.]
[0046] [ Figure 13A Scanning electron microscope images obtained for observing the surface of the test pieces before the weathering tests of Examples 3-4.
[0047] [ Figure 13B Scanning electron microscope images obtained for observing the surface of the test pieces after the weathering tests of Examples 3-4.
[0048] [ Figure 14 [Graphs showing the weathering resistance test results before and after Example 4-3, Example 4-4 and Comparative Example 4-1.]
[0049] [ Figure 15A [Scanning electron microscope image obtained for observing the surface of the test piece before the weathering test of Example 4-3.]
[0050] [ Figure 15B [Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Example 4-3.]
[0051] [ Figure 16A [Scanning electron microscope image obtained for observing the surface of the test piece before the weathering test of Example 4-4.]
[0052] [ Figure 16B [Scanning electron microscope image obtained for observing the surface of the test piece after the weathering test of Examples 4-4.]
[0053] [ Figure 17 [A graph showing the molecular weight determination results before and after the weathering test of Example 4.]
[0054] [ Figure 18 [Graph showing the water absorption rate of biodegradable resin, or biodegradable resin with each biodegradation accelerator added.]
[0055] [ Figure 19 To show the hydrogen ion index (pH) of biodegradable resin, or biodegradable resin with each added biodegradation accelerator, and per 1 cm³, 3 A graph showing the relationship between the water absorption of the biodegradable resin contained in the molded body.
[0056] [ Figure 20 This is a graph showing the relationship between the hydrogen ion index (pH) of biodegradable resin, or biodegradable resin with each added biodegradation promoter, and the water absorption of 1g of resin. Detailed Implementation
[0057] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the embodiments described below are merely examples and are not intended to exclude the application of various modifications and techniques not explicitly shown. The present disclosure can be implemented with various modifications (e.g., combining embodiments, etc.) without departing from its spirit.
[0058] The biodegradable resin composition and molded articles disclosed herein will be described. The biodegradable resin composition of this embodiment can be applied to various products such as commonly used packaging, agricultural materials and horticultural materials, and is particularly suitable for products that are difficult to reuse or recycle due to easy adhesion of dirt, and thus easily become waste.
[0059] <Composition of the Biodegradable Resin Composition>
[0060] The biodegradable resin composition contains a biodegradable resin and has water-retention properties that promote the hydrolysis of the biodegradable resin. Relative to 1g of biodegradable resin, the biodegradable resin composition preferably retains 0.007g to 15.0g of water, more preferably 0.008g to 15.0g of water, and even more preferably 0.008g to 0.5g of water.
[0061] In such biodegradable resin compositions, it is preferable that a biodegradation promoter that promotes the biodegradation of the biodegradable resin is included together with the biodegradable resin.
[0062] The following provides a detailed description of biodegradable resins, biodegradation accelerators, and other additives.
[0063] (Biodegradable resin)
[0064] The biodegradable resin included in the biodegradable resin composition disclosed herein is preferably a biodegradable resin having ester bonds and being reduced in molecular weight by hydrolysis cleaving the ester bonds. Examples of such biodegradable resins include polylactic acid (PLA), polybutylene succinate (PBS), and polybutylene terephthalate adipate (PBAT).
[0065] (Biodegradation accelerator)
[0066] Biodegradation accelerators are additives that promote the hydrolysis of biodegradable resins. Therefore, biodegradation accelerators are preferably materials that improve the water retention capacity of biodegradable resins. Furthermore, in cases where the biodegradable resin composition containing the biodegradation accelerator is discarded in the soil, the biodegradable resin composition can activate soil microorganisms. Therefore, by including the biodegradation accelerator, the biodegradable resin composition can not only promote the hydrolysis of the biodegradable resin but also improve its biodegradability. Additionally, from the viewpoint of environmental impact, biodegradation accelerators are preferably substances derived from nature.
[0067] As such a biodegradation promoter, polysaccharides derived from seaweed are preferred, more preferably including at least one of fucoidan, laminarin, alginate, and alginate. Mannitol may also be included together with at least one of fucoidan, laminarin, alginate, and alginate. Alginic acid or alginate is further preferred as a biodegradation promoter. As an alginate, at least one of sodium alginate, potassium alginate, and calcium alginate is preferred, more preferably sodium alginate. Here, fucoidan, mannitol, and laminarin are preferably used together with alginate or alginate.
[0068] In addition, the biodegradation promoter is preferably either acidic or alkaline, except for neutral.
[0069] Such biodegradation promoters can be extracted from natural materials or produced industrially.
[0070] The biodegradation accelerator preferably contains 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, relative to the biodegradable resin. When the biodegradation accelerator is included within this range, it promotes the hydrolysis of the biodegradable resin. The higher the content of the biodegradation accelerator, the greater the hydrolysis promoting effect, therefore it is preferred.
[0071] On the other hand, from the viewpoint of the strength of the resin molded article and the viewpoint of the moldability of the resin using biodegradable resin, the lower the amount of biodegradation accelerator added relative to the biodegradable resin, the better. For example, suppose the molded article using biodegradable resin is formed by injection molding, blow molding, vacuum forming, blow molding, or extrusion molding. In this case, the biodegradation accelerator preferably contains 50% by mass or less, more preferably 30% by mass or less, and even more preferably 10% by mass or less relative to the biodegradable resin. In addition, it is also possible to assume various forming methods such as using solvents or the like to increase the melt flow rate (MFR) and forming a film on the surface of a film or sheet using a die-coating machine with a T-die. According to such forming methods, the amount of biodegradation accelerator added relative to the biodegradable resin is not necessarily limited to 50% by mass or less, and can also be set to an amount exceeding 50% by mass.
[0072] From the above, in order to improve the effect of hydrolyzing biodegradable resin, increase the strength of the resin molded body, and make it suitable for resin molding, the hydrolysis accelerator preferably contains 0.01% to 50% by mass, more preferably 0.1% to 30% by mass, and even more preferably 0.5% to 10% by mass, relative to the biodegradable resin.
[0073] It should be noted that the upper limit of the hydrolysis accelerator content can be adjusted appropriately according to the method used to form the biodegradable resin.
[0074] In a molded article formed from a biodegradable resin containing such a hydrolysis accelerator, it is preferable to retain 0.007g to 15.0g of water relative to 1g of biodegradable resin, more preferably to retain 0.008g to 15.0g of water, and even more preferably to retain 0.008g to 0.5g of water. Additionally, per 1cm 3 The biodegradable resin contained in the molded body is preferably capable of retaining 0.009g to 15.0g of water. Furthermore, the molded body preferably contains a certain amount of water per 1cm³. 3 It can hold water at a concentration between 0.009g and 15.0g.
[0075] (Photocatalytically active substances)
[0076] Photocatalytic active materials are catalysts that can degrade biodegradable resins through light (photodegradability). Photocatalytic active materials promote the degradation of the light-exposed portions of the biodegradable resin, while leaving the unexposed portions intact. Thus, by inducing multiple fine decompositions within the biodegradable resin, the surface area of the remaining resin is increased, thereby further enhancing biodegradability.
[0077] By irradiating the photocatalytically active substances contained in the biodegradable resin composition with light, the photocatalytically active substances oxidize water in the air or water, or reduce oxygen to generate reactive oxygen species, thereby oxidizing and decomposing the biodegradable resin. The photodegradation of the biodegradable resin using such photocatalytically active substances occurs at a stage earlier than the biodegradation of the resin itself. Therefore, the photocatalytically active substances can reduce the molecular weight of the biodegradable resin before biodegradation occurs, thereby increasing the surface area of the resin and further promoting its biodegradation.
[0078] Examples of such photocatalytically active materials include titanium dioxide or tungsten oxide.
[0079] The photocatalyst is preferably present in an amount of 0.5% to 10% by mass, more preferably 1.0% to 5.0% by mass, relative to the overall biodegradable resin composition. The presence of a photocatalyst within this range allows the photodegradability of the biodegradable resin to be utilized. It should be noted that the upper limit of the photocatalytically active substance content can be appropriately adjusted depending on the method used to form the biodegradable resin.
[0080] (Other additives)
[0081] The biodegradable resin composition may also contain other additives that promote the decomposition of the biodegradable resin. For example, it may further contain organic or inorganic materials that are mixed with the biodegradable resin and leave a residue of the biodegradable resin through their own decay.
[0082] Such organic materials are preferably plant fibers or plant flakes, and more preferably rice bran, old rice, rice straw, rice husks, wheat husks, wheat bran, soybean husks, coffee residue, tea residue, coconut shells, bagasse, wood flour, waste paper, starch, etc.
[0083] In addition, calcium carbonate is preferred as an inorganic material.
[0084] Organic and inorganic materials are preferably in filler-like shapes. This is because, when organic materials are in filler-like shapes, i.e., when the biodegradable resin composition contains organic fillers, each organic filler is prone to decay, which easily creates pores in the molded body of the biodegradable resin composition or causes the shape to break, thereby increasing the surface area. Furthermore, this is because, when inorganic materials are in filler-like shapes, i.e., when the biodegradable resin composition contains inorganic fillers, the biodegradable resin surrounding the inorganic filler deteriorates, causing the inorganic filler to detach from the biodegradable resin, thereby creating pores in the molded body of the biodegradable resin composition and easily causing the shape of the molded body of the biodegradable resin composition to break, thereby increasing the surface area.
[0085] <Resin Molded Body>
[0086] The above-mentioned biodegradable resin composition is preferably formed into processed products such as molded articles, films, and sheets.
[0087] Molded bodies are formed into desired shapes, for example, by injection molding, blow molding, vacuum forming, etc.
[0088] In addition, the film can be formed to the desired thickness, for example, by blow molding.
[0089] Furthermore, the sheet can be formed to the desired thickness, for example, by extrusion molding.
[0090] In addition, the desired thickness can be formed on the surface of films or sheets of different materials, for example, by means of a die-coating machine.
[0091] [Example]
[0092] The biodegradable resin compositions of this disclosure will now be described in detail through various embodiments.
[0093] <Example 1>
[0094] The additives added to the biodegradable resin were varied to form a biodegradable resin composition, and the tensile strength of the test pieces using the biodegradable resin composition was confirmed.
[0095] (Example 1-1)
[0096] Compared to polylactic acid (PLA), a biodegradable resin, a mixture of alginic acid containing 30% by mass of alginic acid, 5% by mass of laminarin, 10% by mass of fucoidan, and 8% by mass of mannitol was added to obtain the biodegradable resin composition of Example 1-1. In this case, the amount of alginic acid mixture added to the biodegradable resin composition was 0.5% by mass.
[0097] (Examples 1-2)
[0098] Except that the additive was alginic acid, the biodegradable resin compositions of Examples 1-2 were obtained in the same manner as in Examples 1-1.
[0099] (Examples 1-3)
[0100] Except that sodium alginate was used as the additive, the biodegradable resin compositions of Examples 1-3 were obtained in the same manner as in Examples 1-1.
[0101] (Examples 1-4)
[0102] Except that the additive was fucoidan, the biodegradable resin compositions of Examples 1-4 were obtained in the same manner as in Examples 1-1.
[0103] (Comparative Example 1-1)
[0104] Except that no additives were added, the biodegradable resin composition of Comparative Example 1-1 was obtained in the same manner as in Example 1-1.
[0105] [evaluate]
[0106] (Tension test)
[0107] Using the biodegradable resin compositions described in the examples and comparative examples, resin films were formed by extrusion molding. The film thickness of the resin films in the examples and comparative examples was 0.4 mm in Examples 1-1 to 1-3 and Comparative Example 1-1, and 0.5 mm in Examples 1-4. Rectangular test pieces with a length of 100 mm in the stretching direction and a length of 15 mm in the direction orthogonal to the stretching direction were cut from these resin films; five samples were cut from each example and comparative example.
[0108] Next, in a tensile testing machine (Shimadzu Corporation, AG-X 10kN), the test piece was fixed with a clamping distance (chuck distance) of 50 mm. At a temperature of 23°C and a humidity of 50% RH, both ends of the test piece were stretched at a tensile speed of 500 mm / min, and the tensile force at fracture was measured. Each measurement was performed five times (five samples), and the average value of the measurements for each example and comparative example was taken as the tensile force at fracture.
[0109] (Accelerated degradation test)
[0110] The average value of the measurements of each embodiment and comparative example obtained in the tensile test will be used as the tensile force at break (initial tensile force) before the test (when stored for 0 hours).
[0111] Next, the test pieces (5 samples each) obtained in the same manner as the tensile test were stored at 60°C and 80% RH for 96 hours. Then, under the same conditions as the tensile test, the measurements of each example and comparative example were performed 5 times (5 samples each), and the average value of the measurements of each example and comparative example was taken as the tensile force at fracture after the test (tensile force after deterioration).
[0112] (Molecular weight determination)
[0113] For test pieces formed using the biodegradable resin compositions described in the various examples and comparative examples, gel permeation chromatography (GPC) analysis was performed before and after storage in a constant temperature and humidity bath (accelerated degradation test) and before and after weathering tests (irradiation with a metal halide lamp) to determine the change in molecular weight of each test piece. The GPC analysis conditions at this time are as follows.
[0114] Columns: 3 semi-micro columns for high-performance analysis (manufactured by Showa Denko Corporation, Shodex GPC KF-405LHQ)
[0115] Flow rate: 0.30 ml / min
[0116] Detector: High-speed GPC device (manufactured by Tosoh Corporation, HLC-8220GPC)
[0117] Testing conditions: Differential refractive index (RI)
[0118] Injection volume: 40 μl
[0119] Column temperature: 40℃
[0120] Elution buffer: chloroform
[0121] Table 1 below shows the evaluation results of the tensile force at fracture relative to the film thickness of the test piece before the accelerated degradation test (when stored for 0 hours) and after the accelerated degradation test. Additionally, Figure 1 A graph showing the results of the accelerated degradation test is provided. Table 2 also shows the evaluation results of the molecular weight changes before and after the accelerated degradation test. Figures 2A to 2F To illustrate the change in molecular weight before and after the accelerated degradation test, Figure 2A To illustrate the molecular weight curves of each embodiment and comparative example before the accelerated degradation test, Figure 2B To illustrate the changes in molecular weight before and after the accelerated degradation test in Example 1-1, Figure 2C To illustrate the changes in molecular weight before and after the accelerated degradation tests in Examples 1-2, Figure 2D To illustrate the changes in molecular weight before and after the accelerated degradation tests in Examples 1-3, Figure 2E To illustrate the changes in molecular weight before and after the accelerated degradation tests in Examples 1-4, Figure 2F A graph showing the change in molecular weight before and after the accelerated degradation test of Comparative Example 1-1.
[0122]
[0123]
[0124] As shown in Table 1 and Figure 1 As shown, the test pieces formed from the biodegradable resin compositions of Examples 1-1 to 1-4, which possess water-retaining properties by adding alginic acid or alginate to the biodegradable resin, exhibited lower tensile strength (tensile force per film thickness at break) than the test pieces formed from the biodegradable resin composition of Comparative Example 1-1, which does not contain additives. In particular, the test pieces formed from the biodegradable resin compositions of Examples 1-1 (with an alginate mixture added to the biodegradable resin), Examples 1-3 (with sodium alginate added), and Examples 1-4 (with fucoidan added) exhibited lower tensile strength than the test pieces formed from the biodegradable resin composition of Comparative Example 1-1 in both the tensile test and the accelerated degradation test.
[0125] Furthermore, according to the results of the accelerated degradation test, the fracture strength of the test pieces formed from the biodegradable resin compositions of Examples 1-1 to 1-3, which contained alginate mixtures, alginate, or sodium alginate, was lower than that of the test pieces formed from the biodegradable resin composition of Comparative Example 1-1. Therefore, the test pieces formed from the biodegradable resin compositions of Examples 1-1 to 1-3 showed significant degradation under humid conditions. It is believed that this is due to the water-retention effect of alginate, which leads to particularly significant degradation.
[0126] Furthermore, based on the results of the accelerated degradation test, compared to the test piece formed from the biodegradable resin composition of Comparative Example 1-1, the test piece formed from the biodegradable resin composition of Examples 1-2 with added alginic acid exhibited higher initial tensile strength and lower tensile strength after the accelerated degradation test. This is because the resin product has high strength in the initial stage of formation (during use), but then deterioration caused by hydrolysis develops rapidly and it is easily decomposed by microorganisms, thus making it particularly preferred.
[0127] Additionally, as shown in Table 2 and Figure 2A As shown, before the accelerated degradation test, compared with the test piece formed from the biodegradable resin composition of Comparative Example 1-1 without the addition of a biodegradation accelerator, the peak of the test piece formed from the biodegradable resin compositions of Examples 1-1 to 1-4, which included alginate mixture, alginate, alginate salt, and fucoidan, shifted to the left side of the curve, indicating a decrease in molecular weight. Additionally, as... Figures 2B to 2E As shown in Table 2, the molecular weight of the test pieces formed from the biodegradable resin compositions of Examples 1-1 to 1-4 decreased after the accelerated degradation test. Compared with Comparative Example 1-1, the rate of decrease in molecular weight was greater.
[0128] <Example 2>
[0129] The amount of alginate mixture added to the biodegradable resin was varied to form a biodegradable resin composition, and the tensile strength of the test pieces using the biodegradable resin composition was confirmed.
[0130] (Example 2-1)
[0131] Similar to Examples 1-1, the biodegradable resin composition of Example 2-1 was obtained by adding the alginate mixture in an amount of 0.5% by mass.
[0132] (Example 2-2)
[0133] Except that the amount of alginate mixture added was set to 1.0% by mass, the biodegradable resin composition of Example 2-2 was obtained in the same manner as the biodegradable resin composition of Example 2-1.
[0134] (Comparative Example 2-1)
[0135] Except for the absence of the alginate mixture, the biodegradable resin composition of Comparative Example 2-1 was obtained in the same manner as the biodegradable resin composition of Example 2-1. Here, Comparative Example 2-1 has the same composition as Comparative Example 1-1.
[0136] [evaluate]
[0137] (Tension test)
[0138] Similar to Example 1, tensile tests were performed on test pieces formed using the biodegradable resin compositions described in each example and comparative example to obtain the average tensile force at break.
[0139] (Accelerated degradation test)
[0140] Similar to Example 1, accelerated degradation tests were conducted on test pieces formed using the biodegradable resin compositions described in each example and comparative example to obtain the average tensile force at break.
[0141] (Weather resistance test)
[0142] For test pieces (before accelerated degradation tests) formed using the biodegradable resin compositions described in the various examples and comparative examples, a metal halide lamp was irradiated under the following conditions. Then, a tensile test was performed under the same conditions as the tensile test in Example 1, and the average tensile force at fracture of the test piece after metal halide lamp irradiation was obtained. Then, the fracture strength after metal halide lamp irradiation relative to the film thickness of the test piece was calculated.
[0143] Temperature: 60℃
[0144] Humidity: 50% RH
[0145] Water spray circulation: 18 minutes / 2 hours
[0146] Radiation intensity: 1.5 kW / m² 2 (Metal halide lamp wavelength: 295nm to 450nm)
[0147] Irradiation time: 8 hours
[0148] In addition, the surface of the test pieces formed using the biodegradable resin compositions described in the various examples and comparative examples after irradiation with a metal halide lamp was observed using a scanning electron microscope (SEM).
[0149] (Molecular weight determination)
[0150] For test pieces formed using the biodegradable resin compositions described in the various examples and comparative examples, gel permeation chromatography (GPC) analysis was performed before and after storage in a constant temperature and humidity bath (accelerated degradation test) and before and after weathering tests (irradiation with a metal halide lamp) to determine the change in molecular weight of each test piece. The GPC analysis conditions were the same as in Example 1.
[0151] In addition, for the test pieces formed using the biodegradable resin compositions described in the various examples and comparative examples, gel permeation chromatography analysis was performed after irradiation with a metal halide lamp to determine the molecular weight of each test piece. The GPC analysis conditions at this time were as described above. Furthermore, the metal halide lamp irradiation conditions at this time were set to the same conditions as the weather resistance test in Example 2.
[0152] In addition, for test pieces formed using the biodegradable resin composition described in Comparative Example 1-1, the test pieces were further irradiated with a metal halide lamp for twice the time (i.e., 16 hours), and then gel permeation chromatography was performed to determine the molecular weight of the test pieces.
[0153] Table 3 below shows the evaluation results of accelerated degradation test and weathering test. Additionally, Table 4 below shows the evaluation results of the change in molecular weight before and after the accelerated degradation test, and Table 5 shows the evaluation results of the change in molecular weight before and after the weathering test.
[0154] in addition, Figure 3 The results of the accelerated degradation test are shown in the graph. Figure 4 The results of the weather resistance test are shown in a graph. Additionally, Figures 5A to 7C The images shown are scanning electron microscope (SEM) images of the test pieces before each test, after the accelerated degradation test, and after the weathering test. Figure 5A , Figure 5B and Figure 5C Before each test of the test pieces formed using the biodegradable resin composition of Example 2-1 ( Figure 5A After accelerated degradation test ( Figure 5B ) and after weather resistance test ( Figure 5C ) surface SEM image. Figure 6A , Figure 6B and Figure 6C Before each test of the test pieces formed using the biodegradable resin compositions of Examples 2-2 ( Figure 6A After accelerated degradation test ( Figure 6B ) and after weather resistance test ( Figure 6C ) surface SEM image. Figure 7A , Figure 7B and Figure 7C Before the accelerated degradation test of the test piece formed using the biodegradable resin composition of Comparative Example 2-1 ( Figure 7A After accelerated degradation test ( Figure 7B ) and after weather resistance test ( Figure 7C ) surface SEM image. Additionally. Figure 8 The graph shows the changes in molecular weight before and after the accelerated degradation test. Additionally, Figures 9A to 9D The graph shows the changes in molecular weight before and after the weathering test. Figure 9A The graphs shown are for comparing the molecular weight measurements of the various embodiments and comparative examples before irradiation with metal halide lamps. Figure 9B A graph showing the molecular weight of the metal halide lamp before and after irradiation in Example 2-1. Figure 9C The graph shown is a comparison of the molecular weights of the metal halide lamps used in Examples 2-2 before and after irradiation. Figure 9D The graph is shown to compare the molecular weight of the metal halide lamp before and after irradiation in Comparative Example 1-1.
[0155]
[0156]
[0157]
[0158] As shown in Table 3 and Figure 3 and Figure 4As shown, the test pieces formed from the biodegradable resin compositions of each example and comparative example exhibited increased fracture strength after irradiation with a metal halide lamp. This is believed to be because the polylactic acid crystallizes upon irradiation with the metal halide lamp, thus increasing its strength. However, it was confirmed that the test pieces formed from the biodegradable resin compositions of Examples 2-1 and 2-2 (with added alginate) showed lower fracture strength compared to Comparative Example 2-1 without the alginate mixture, indicating that the biodegradable resin was more prone to decomposition. Furthermore, compared to the test pieces formed from the biodegradable resin compositions of Examples 2-1 and 2-1, the test piece formed from the biodegradable resin composition of Example 2-2 showed a greater decrease in fracture strength after irradiation with a metal halide lamp, and the rate of decrease in fracture strength was also higher. This confirms that the higher the amount of alginate mixture added, the easier the biodegradable resin is to decompose.
[0159] like Figure 5A and Figure 5B ,as well as Figure 6A and Figure 6B As shown, it was confirmed that the test pieces formed from the biodegradable resin compositions of Examples 2-1 and 2-2 with added alginate mixture developed pores in the test pieces after accelerated degradation testing. Figure 5B The dotted line portion shown and Figure 6B The dotted and dashed areas shown) or depressions ( Figure 6B The dotted line area shown represents the deterioration of the test piece. It is believed that this type of clearly defined and large void (see reference) that forms in the test piece after accelerated deterioration testing... Figure 5B ) or clearly defined, small pores or depressions distributed throughout the test piece (see reference) Figure 6B The pores are created by the alginate mixture.
[0160] On the other hand, unlike the test pieces of Examples 2-1 and 2-2, Figure 7A and Figure 7B The test pieces formed from the biodegradable resin composition of Comparative Example 2-1 without the addition of alginate were not observed to have clearly defined large pores or clearly defined small pores or depressions distributed in the test pieces.
[0161] like Figure 5A and Figure 5C ,as well as Figure 6A and Figure 6C As shown, it was confirmed that the test pieces formed from the biodegradable resin compositions of Examples 2-1 and 2-2 with added alginate mixture developed pores, i.e., the test pieces deteriorated, after the weathering test. It is believed that these pores were caused by the alginate mixture.
[0162] on the other hand, Figure 7A and Figure 7C The test pieces formed from the biodegradable resin composition of Comparative Example 2-1 without the addition of alginate were observed to have small and irregularly shaped pores (voids caused by resin deterioration) on the entire surface, but no pores as large as those in the test pieces of Examples 2-1 and 2-2 were observed.
[0163] Figure 8 A graph showing the molecular weight determination results of the biodegradable resin compositions in the test pieces of each example and comparative example before and after the accelerated degradation test.
[0164] like Figure 8 As shown in Table 4, before the accelerated degradation test, compared with the test piece formed from the biodegradable resin composition of Comparative Example 2-1 without the addition of the alginate mixture, the peak of the test piece formed from the biodegradable resin compositions of Examples 2-1 and 2-2 with the addition of the alginate mixture shifted to the left in the curve, and the molecular weight decreased. Additionally, as... Figure 8 As shown, the molecular weight of the test piece formed from the biodegradable resin compositions of Examples 2-1 and 2-2 decreased after the accelerated degradation test.
[0165] Figures 9A to 9D A graph showing the molecular weight determination results of the biodegradable resin compositions in the test pieces of each example and comparative example before and after the weathering test. Figure 9A A graph showing the molecular weight of the biodegradable resin composition in the test pieces of Examples 2-1, 2-2, and Comparative Example 2-1 before irradiation with a metal halide lamp. Additionally, Figure 9B To illustrate the molecular weight curves of the biodegradable resin composition in the test pieces before and after irradiation with a metal halide lamp in Example 2-1, Figure 9C To illustrate the molecular weight curves of the biodegradable resin composition in the test pieces before and after irradiation with the metal halide lamp in Example 2-2, Figure 9D A graph showing the molecular weight of the biodegradable resin composition in the test piece before and after irradiation with a metal halide lamp in Comparative Example 2-1.
[0166] like Figure 9A As shown in Table 5, before metal halide lamp irradiation (weather resistance test), compared with the test piece formed by the biodegradable resin composition of Comparative Example 2-1 without the addition of alginate mixture, the peak of the test piece formed by the biodegradable resin composition of Examples 2-1 and 2-2 with the addition of alginate mixture shifted to the left in the curve, and the molecular weight decreased.
[0167] In addition, such as Figure 9B and Figure 9CAs shown in Table 5, the molecular weight of the test pieces formed from the biodegradable resin compositions of Examples 2-1 and 2-2 decreased after irradiation with a metal halide lamp, particularly in the test pieces formed from the biodegradable resin composition of Example 2-2. At this time, compared with... Figure 9D Compared with Comparative Example 2-1 shown in Table 5, which had the same irradiation time, the molecular weight was significantly reduced, to the same extent as when the irradiation time was twice that of the previous example.
[0168] The above confirms that the more additives such as alginate mixture are added, the lower the tensile strength, meaning that the biodegradable resin is more easily decomposed.
[0169] <Example 3>
[0170] The additives added to the biodegradable resin were varied to form a biodegradable resin composition, and the tensile strength of the test pieces using the biodegradable resin composition was confirmed.
[0171] (Example 3-1)
[0172] A mixture of alginate and titanium dioxide (rutile type) as a photocatalyst were added to PLA (polylactic acid) as a biodegradable resin to obtain the biodegradable resin composition of Example 3-1. In this case, the amount of alginate added to the biodegradable resin composition was 0.5% by mass, and the amount of titanium dioxide added to the biodegradable resin composition was 3.0% by mass. Using this biodegradable resin composition, a resin film with a thickness of 0.4 mm was formed by extrusion molding, thereby obtaining the test piece of Example 3-1.
[0173] (Example 3-2)
[0174] Except that the thickness of the resin film was set to 0.2 mm, test pieces using the biodegradable resin composition of Example 3-2 were obtained in the same manner as in Example 3-1.
[0175] (Example 3-3)
[0176] Except that the additive was alginic acid, test pieces using the biodegradable resin composition of Example 3-3 were obtained in the same manner as in Example 3-2.
[0177] (Examples 3-4)
[0178] Except that sodium alginate was used as the additive, test pieces using the biodegradable resin composition of Examples 3-4 were obtained in the same manner as in Examples 3-2.
[0179] (Comparative Example 3-1)
[0180] Except that no additives were added, test pieces using the biodegradable resin composition of Comparative Example 3-1 were obtained in the same manner as in Example 3-1.
[0181] (Comparative Example 3-2)
[0182] Except that no additives were added, test pieces using the biodegradable resin composition of Comparative Example 3-2 were obtained in the same manner as in Example 3-2.
[0183] [evaluate]
[0184] (Tension test)
[0185] Similar to Example 1, tensile tests were performed on test pieces formed using the biodegradable resin compositions described in each example and comparative example to obtain the average tensile force at break.
[0186] (Weather resistance test)
[0187] Similar to Example 2, test pieces formed using the biodegradable resin compositions described in each example and comparative example were irradiated with a metal halide lamp and then subjected to tensile tests to obtain the average value of the tensile force at break.
[0188] (Molecular weight determination)
[0189] Similar to Example 2, for test pieces formed using the biodegradable resin compositions described in each example and comparative example, the changes in molecular weight of each test piece before and after the accelerated degradation test (stored in a constant temperature and humidity bath) and before and after the weathering test (irradiation by a metal halide lamp) were measured.
[0190] Table 6 below shows the evaluation results of the tensile force at break relative to film thickness for the test pieces of each embodiment and comparative example before and after the weathering resistance test. Additionally, Table 7 below shows the evaluation results of the molecular weight of the test pieces of each embodiment and comparative example before and after the weathering resistance test. Furthermore, Figure 10A To compare the molecular weight determination results of the test pieces of each embodiment and comparative example before irradiation with a metal halide lamp, a graph is shown. Figure 10B To compare the molecular weight curves before and after irradiation with metal halide lamps in Examples 3-2, Figure 10C To compare the molecular weight curves before and after irradiation with metal halide lamps in Examples 3-3, Figure 10D To compare the molecular weight curves before and after irradiation with metal halide lamps in Examples 3-4, Figure 10E To compare the molecular weight curves of the metal halide lamps before and after irradiation in Comparative Example 3-2, we present graphs. Additionally, Figure 11A and Figure 11B The following are SEM images of the surface of the test pieces before and after the weathering resistance test in Example 3-2. Figure 12Aand Figure 12B The following are SEM images of the surface of the test pieces before and after the weathering resistance test in Example 3-3. Figure 13A and Figure 13B The SEM images of the test pieces before and after the weathering tests of Examples 3-4 are shown.
[0191]
[0192]
[0193] As shown in Table 6, the test piece formed from the biodegradable resin composition of Example 3-1, which added alginate and titanium dioxide to the biodegradable resin, exhibited a higher tensile strength in the tensile test than the test piece formed from the biodegradable resin composition of Comparative Example 3-1 without alginate, with the same film thickness (0.4 mm). However, it exhibited a lower tensile strength in the weathering test than the test piece formed from the biodegradable resin composition of Comparative Example 3-1. Similarly, the test piece formed from the biodegradable resin composition of Example 3-2, which added alginate and titanium dioxide to the biodegradable resin, showed approximately the same tensile strength as the test piece formed from the biodegradable resin composition of Comparative Example 3-2 without alginate, with the same film thickness (0.2 mm), but exhibited a lower tensile strength in the weathering test. In other words, the resin product exhibited high strength in the initial stage of formation (during use), but then rapidly deteriorated due to hydrolysis and became easily decomposed by microorganisms. Furthermore, the test piece with a thinner film thickness showed a higher degree of deterioration due to hydrolysis.
[0194] In addition, in particular, the test pieces formed from the biodegradable resin compositions of Examples 3-4, in which sodium alginate and titanium dioxide were added to the biodegradable resin, exhibited significantly lower breaking strength in the tensile test.
[0195] In addition, such as Figure 10A As shown in Table 7, before irradiation with a metal halide lamp, compared to the test pieces formed from the biodegradable resin composition of Comparative Example 3-2 without the addition of a biodegradability accelerator, the peaks of the test pieces formed from the biodegradable resin compositions of Examples 3-2 to 3-4, which respectively added alginate mixture, alginate, and sodium alginate, shifted to the left in the graph, indicating a decrease in molecular weight. Furthermore, it was particularly confirmed that the biodegradable resin containing the alginate mixture in Example 3-2 had a particularly small molecular weight, and the biodegradable resin was easily decomposed.
[0196] In addition, such as Figures 10B to 10DAs shown in Table 7, the molecular weight of the test pieces formed from the biodegradable resin compositions of Examples 3-2 to 3-4 tends to decrease easily after irradiation with a metal halide lamp. In particular, the molecular weight of the test pieces formed from the biodegradable resin compositions of Examples 3-4 containing sodium alginate and titanium dioxide decreased significantly.
[0197] From the above, it can be confirmed that when the biodegradable resin composition contains titanium dioxide, the resin product has high strength in the early stage of formation (when in use), but then the biodegradable resin is easily decomposed due to the deterioration effect caused by hydrolysis accelerators (especially sodium alginate).
[0198] like Figures 11A to 13B As shown, it was confirmed that the test piece containing the hydrolysis accelerator and titanium dioxide developed voids and deteriorated after the weathering test.
[0199] <Example 4>
[0200] Alginic acid mixture and titanium dioxide were added to a biodegradable resin, and the amount of alginic acid mixture added was varied to form a biodegradable resin composition. The tensile strength of test pieces with different film thicknesses using the biodegradable resin composition was confirmed.
[0201] (Example 4-1)
[0202] Similar to Example 3-1, the biodegradable resin composition of Example 4-1 was obtained by adding 0.5% by mass of the alginate mixture and 3.0% by mass of the titanium dioxide. Using this biodegradable resin composition, a resin film with a thickness of 0.4 mm was formed by extrusion molding, thereby obtaining the test piece of Example 4-1.
[0203] (Example 4-2)
[0204] Except that the amount of alginate mixture added was 1.0% by mass, the biodegradable resin composition of Example 4-2 was obtained in the same manner as the biodegradable resin composition of Example 4-1. Using such a biodegradable resin composition, a resin film with a thickness of 0.5 mm was formed by extrusion molding, thereby obtaining the test piece of Example 4-2.
[0205] (Example 4-3)
[0206] Except that the thickness of the resin film was set to 0.2 mm, test pieces using the biodegradable resin composition of Example 4-3 were obtained in the same manner as in Example 4-1.
[0207] (Example 4-4)
[0208] Except that the thickness of the resin film was set to 0.2 mm, test pieces using the biodegradable resin composition of Example 4-4 were obtained in the same manner as in Example 4-2.
[0209] (Comparative Example 4-1)
[0210] Except that no alginate mixture was added, the biodegradable resin composition of Comparative Example 4-1 was obtained in the same manner as the biodegradable resin composition of Example 4-1.
[0211] (Comparative Example 4-2)
[0212] Except that the thickness of the resin film was set to 0.2 mm, test pieces using the biodegradable resin composition of Comparative Example 4-2 were obtained in the same manner as Comparative Example 4-1.
[0213] [evaluate]
[0214] (Tension test)
[0215] Similar to Example 1, tensile tests were performed on test pieces formed using the biodegradable resin compositions described in each example and comparative example to obtain the average tensile force at break.
[0216] (Weather resistance test)
[0217] Similar to Example 2, test pieces formed using the biodegradable resin compositions described in each example and comparative example were irradiated with a metal halide lamp and then subjected to tensile tests to obtain the average value of the tensile force at break.
[0218] (Molecular weight determination)
[0219] Similar to Example 2, for test pieces formed using the biodegradable resin compositions described in the various examples and comparative examples, the change in molecular weight of each test piece before and after the weather resistance test (irradiation by a metal halide lamp) was measured.
[0220] Table 8 below shows the evaluation results of the tensile force at break relative to the film thickness for the test pieces of each embodiment and comparative example before and after the weathering resistance test. Additionally, Table 9 below shows the evaluation results of the molecular weight of the test pieces of each embodiment and comparative example before and after the weathering resistance test. Figure 14 A graph showing the tensile force at fracture versus film thickness of the test pieces from Examples 4-3, 4-4, and Comparative Example 4-1 before and after the weathering test is provided. Additionally, Figure 15A and Figure 15B The following are SEM images of the test pieces before and after the weathering resistance test in Examples 4-3. Figure 16A and Figure 16BThe SEM images of the test pieces before and after the weathering resistance test in Examples 4-4 are shown. Furthermore, Figure 17 To compare the molecular weights of metal halide lamps before and after irradiation in Examples 4-3, 4-4, and 4-1, a graph is shown.
[0221]
[0222]
[0223] As shown in Table 8 and Figure 14 As shown, it was confirmed that the test pieces formed from the biodegradable resin compositions of Examples 4-1 to 4-4 with added alginate mixture exhibited reduced fracture strength after irradiation by a metal halide lamp, indicating that the biodegradable resin was easily decomposed. Specifically, it was confirmed that before irradiation by a metal halide lamp, the fracture strength sometimes increased depending on the amount of alginate mixture added (refer to Examples 4-1 and Comparative Examples 4-1, 4-3 and 4-2), but after irradiation by a metal halide lamp, the fracture strength decreased upon addition of the alginate mixture, indicating that the biodegradable resin was easily decomposed. Furthermore, compared to the test pieces formed from the biodegradable resin compositions of Examples 4-1 and 4-3, the test pieces formed from the biodegradable resin compositions of Examples 4-2 and 4-4 showed a greater reduction in fracture strength after irradiation by a metal halide lamp; the higher the amount of alginate mixture added, the higher the rate of reduction in fracture strength.
[0224] This can also be confirmed because: with Figure 15B Compared to the SEM images of the test pieces after the weathering test in Examples 4-3 shown, Figure 16B The SEM images of the test pieces after the weathering test in Examples 4-4 show numerous voids. Additionally, from... Figure 17 The molecular weight of the biodegradable resin in the test pieces after the weathering test can also be confirmed: compared with Example 4-3, the molecular weight peak of the test pieces in Example 4-4 shifts to the left, the molecular weight decreases, and the biodegradable resin is easily decomposed.
[0225] The above confirms that the higher the amount of additives such as alginate mixture, the lower the tensile strength, meaning the more easily the biodegradable resin decomposes. Furthermore, after irradiation with a metal halide lamp, the tensile strength of the test piece was lower than before irradiation, indicating degradation of the test piece. Therefore, it can be confirmed that the biodegradable resin deteriorates due to the photodecomposition of titanium dioxide.
[0226] <Example 5>
[0227] For the use of biodegradable resin (density 1.25 g / cm³) 3Test pieces were formed from biodegradable resin compositions obtained by adding 0.5% or 1.0% by mass of the hydrolysis promoters (alginic acid mixture, alginate, sodium alginate, fucoidan) used in Example 1 to the biodegradable resin, respectively, to confirm the relationship between the water absorption rate and the hydrogen ion index (pH) and water absorption when the test pieces were formed.
[0228] [evaluate]
[0229] (Water absorption rate)
[0230] The mass of a test piece of predetermined size before water absorption is measured, and then the test piece is immersed in water to measure the mass of the test piece after water absorption. At this time, the size of the test piece and the method of immersion in water are set according to the dimensions and methods in JIS K7209. It should be noted that for the immersion of test pieces in water, only biodegradable resin (PLA) containing 1.0% by mass of fucoidan is measured using the method shown in JIS K7209 for determining water absorption (moisture absorption rate (sample number n=4)), while other test pieces are measured using the method shown in JIS K7209 for determining water absorption (moisture absorption rate (sample number n=3)).
[0231] Next, based on the difference between the mass of the test piece after water absorption and the mass of the test piece before water absorption, the amount of water retained in the test piece is calculated.
[0232] Finally, the proportion of water retained in the test piece relative to the mass of the test piece before water absorption was calculated and set as the water absorption rate [%).
[0233] (Water absorption)
[0234] Divide the water absorption of the test piece of the predetermined size, calculated by the above method, by the volume of the test piece to calculate the amount of water absorbed per 1 cm³. 3 The water absorption of the molded body. In test pieces formed from biodegradable resin without hydrolysis accelerators, this was relative to the water absorption per 1 cm. 3 The water absorption rate of the molded body is set relative to 1 cm. 3 The water absorption capacity of biodegradable resins.
[0235] Next, calculate each 1cm 3 The water absorption of the biodegradable resin contained in the molded body. Per 1cm 3 The water absorption of the biodegradable resin contained in the molded body is determined by measuring the water absorption relative to 1 cm³. 3 The amount of water absorbed by the molded body is calculated by multiplying the weight ratio of the biodegradable resin in the test piece.
[0236] Furthermore, the water absorption rate of 1g of biodegradable resin in the molded body was calculated. The water absorption rate of 1g of biodegradable resin is based on the amount of water absorbed per 1cm³. 3 It is calculated based on the water absorption of the biodegradable resin contained in the molded body and the density of the biodegradable resin (PLA).
[0237] Table 10 below shows the values per 1 cm for each test piece. 3 The water absorption of the shaped body, per 1cm 3 The amount of water absorbed by the biodegradable resin contained in the molded body and the amount of water absorbed by 1g of biodegradable resin contained in the molded body.
[0238] in addition, Figure 18 To show the water absorption rate of each test piece, Figure 19 To show the hydrogen ion index (pH) of the hydrolysis promoter and per 1 cm 3 A graph showing the relationship between the water absorption of the biodegradable resin contained in the molded body. Figure 20 A graph showing the relationship between the hydrogen ion index (pH) of the hydrolysis accelerator and the water absorption capacity of 1g of biodegradable resin. It should be noted that... Figure 19 and Figure 20 In the figure, for ease of comparison, the water absorption of biodegradable resin (PLA) without hydrolysis accelerator is shown at the position of pH=0.
[0239] [Table 10]
[0240]
[0241] like Figure 18 As shown in Table 10, the water absorption rate of molded articles formed from biodegradable resins containing hydrolysis accelerators is over 70%, while the water absorption rate of molded articles formed from biodegradable resins without hydrolysis accelerators is less than 70%. Compared with biodegradable resin (PLA) monomers, biodegradable resins (PLA) with added alginate mixture, alginate, sodium alginate, and fucoidan as hydrolysis accelerators tend to have higher water absorption rates. In particular, the water absorption rate of biodegradable resins mixed with 1.0% alginate mixture is significantly increased.
[0242] In addition, such as Figure 19 As shown in Table 10, the hydrolysis accelerator is preferably acidic or alkaline, and per 1 cm 3 The amount of water absorbed by the biodegradable resin in the molded body formed from the biodegradable resin with added hydrolysis accelerator is 0.009g or more, preferably 0.01g or more.
[0243] In addition, such as Figure 20 As shown in Table 10, the hydrolysis accelerator is preferably acidic or alkaline, and per 1 cm 3 The amount of water absorbed by the biodegradable resin in the molded body formed from the biodegradable resin with added hydrolysis accelerator is 0.009g or more, preferably 0.01g or more.
[0244] The embodiments of this disclosure have been described above. However, the above embodiments exemplify apparatus and methods for embodying the technical concept of this disclosure. The technical concept of this disclosure is not specific to the material, shape, structure, or arrangement of the constituent components. Various modifications can be made to the technical concept of this disclosure within the scope defined by the claims.
Claims
1. A biodegradable resin composition having water-retaining properties, It consists solely of a biodegradable resin and a hydrolysis accelerator that promotes the hydrolysis of the biodegradable resin. The biodegradable resin is polylactic acid. The hydrolysis accelerator comprises fucoidan, laminarin, mannitol, and alginate or alginate. The hydrolysis accelerator is present in an amount of 0.01% to 1.0% by mass relative to the biodegradable resin.
2. The biodegradable resin composition according to claim 1, wherein, The biodegradable resin can retain 0.007g to 15.0g of water relative to 1g of the resin.
3. The biodegradable resin composition according to claim 1, wherein, The alginate is at least one of sodium alginate, potassium alginate, and calcium alginate.
4. The biodegradable resin composition according to claim 1 or 3, wherein, The hydrolysis accelerator is acidic or alkaline.
5. A molded article formed from the biodegradable resin composition according to any one of claims 1 to 4.
6. The molded article according to claim 5, wherein, Relative to each 1cm 3 The biodegradable resin contained in the molded body is capable of retaining 0.009g to 15.0g of water.
Citation Information
Patent Citations
Polylactic acid (PLA) nano composite material and preparation method thereof
CN110229484A