A biodegradable polylactic acid car floor mat

Abstract

The present invention discloses an easily degradable polylactic acid automobile floor mat, which includes a floor mat body. The floor mat body includes a polylactic acid fiber surface layer, a first polylactic acid fiber layer dispersed with sodium ions, a polylactic acid plastic film layer, a second polylactic acid fiber layer dispersed with chloride ions, and a polylactic acid resin bottom layer; the first polylactic acid fiber layer is prepared by mixing and dispersing the solid powders of sodium salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, and then using a wet forming technology for papermaking, followed by pressing and drying; the second polylactic acid fiber layer is prepared by mixing and dispersing the solid powders of chloride salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, and then using a wet forming technology for papermaking, followed by pressing and drying. The floor mat of the present invention adopts a specific multi-layer structure and material formulation process, has a long service life, and has a relatively fast degradation rate after being discarded, avoiding environmental pollution.

Description

Technical Field

[0001] The present invention relates to an automotive floor mat, and more particularly to a degradable polylactic acid automotive floor mat. Background Art

[0002] With the popularization of automobiles, automotive floor mats have become indispensable consumer goods for people. Automotive floor mats play a role in protecting the interior floor of the vehicle and at the same time serve as an aesthetic and comfortable embellishment. Most traditional automotive floor mats use polyvinyl chloride (PVC) or rubber as the main material. However, with the continuous improvement of people's cultural qualities and the increasing awareness of environmental protection, people are increasingly aware of the pollution caused by PVC and rubber to the environment. Because after PVC and rubber are discarded, their strong stability can exist in the natural environment for a long time, becoming one of the important pollution sources in people's production and life.

[0003] Polylactic acid is a new type of plastic material, which is mainly synthesized by lactic acid copolymerization. It can be completely degraded into water and carbon dioxide in the soil, meeting the requirements of green environmental protection, causing less damage to the environment, and having broad application prospects. Using polylactic acid to manufacture automotive floor mats is expected to solve the pollution problems caused by rubber and PVC floor mats.

[0004] The main principle of the degradation of polylactic acid in the soil is as follows: First, polylactic acid will first undergo a hydrolysis reaction, the ester groups in the structure will break, and the overall structure of polylactic acid will be cleaved, allowing microorganisms to enter the interior of the polylactic acid tissue. Subsequently, the microorganisms will further degrade the remaining short chains of polylactic acid, completely degrading it into water and carbon dioxide. In the above process, due to the tight overall structure of polylactic acid, under the intermolecular dipole force, the long chains of polylactic acid molecules generally have a relatively regular arrangement structure. Therefore, water is not easily infiltrated into the tissue interior, and thus the hydrolysis process occurs relatively slowly. Therefore, its actual degradation rate in the soil is relatively slow, generally taking two to three years to complete the degradation process. The characteristic of slow degradation rate of existing polylactic acid materials has restricted their applications. From the perspective of manufacturing automotive floor mats, using a large amount of polylactic acid materials to manufacture floor mats, the discarded old floor mats will still cause environmental pollution. Summary of the Invention

[0005] In order to overcome the above deficiencies of the prior art, the present invention provides a degradable polylactic acid automotive floor mat, which has a long service life and enables the discarded old floor mats to be degraded in a short time, avoiding environmental pollution, by adopting a specific multi-layer structure and material formulation process.

[0006] The technical solution of the present invention is as follows:

[0007] A biodegradable polylactic acid automotive floor mat, including a floor mat body, which sequentially includes a polylactic acid fiber surface layer, a first polylactic acid fiber layer dispersed with sodium ions, a polylactic acid plastic film layer, a second polylactic acid fiber layer dispersed with chloride ions, and a polylactic acid resin bottom layer from top to bottom; the thickness of the polylactic acid plastic film layer is 0.5 - 1 mm, and by weight, it includes: 60 - 70 parts of polylactic acid resin, 33 - 50 parts of polystyrene, 0.6 - 1.3 parts of titanium dioxide photosensitizer, 1.5 - 3 parts of compatibilizer, 1 - 20 parts of other additives, and 9 - 16 parts of a first porous filler carrier;

[0008] The first polylactic acid fiber layer is obtained by mixing and dispersing the solid powders of sodium salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, then using a wet forming technique for papermaking, and after pressing and drying;

[0009] The second polylactic acid fiber layer is obtained by mixing and dispersing the solid powders of chloride salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, then using a wet forming technique for papermaking, and after pressing and drying;

[0010] The polylactic acid resin bottom layer is formed by injection molding of injection-grade polylactic acid resin.

[0011] Furthermore, the polylactic acid fiber surface layer is obtained by mixing and dispersing the solid powders of a second porous filler carrier and processing aids with water-absorbing fibers to obtain a mixed slurry, then using a wet forming technique for papermaking, and after pressing and drying.

[0012] Furthermore, in the polylactic acid fiber surface layer, the first polylactic acid fiber layer and the second polylactic acid fiber layer, the water-absorbing fiber is modified polylactic acid; the modified polylactic acid includes first using an organic quaternary ammonium salt, alkyl amino acid, polymer monomer, or coupling agent as a modifier to modify montmorillonite to obtain organically modified montmorillonite; then mixing the obtained organically modified montmorillonite with polylactic acid to obtain modified polylactic acid.

[0013] Furthermore, the first porous filler carrier includes one of diatomite, bentonite, porous ceramic alumina, or expanded graphite; the second porous filler carrier includes one of porous ceramic alumina or expanded graphite; the other additives include one or more of a coupling agent, reinforcing glass fiber, and SBS elastomer.

[0014] Furthermore, the processing aids include one or more of an antibacterial agent, anti-ozone agent, coupling agent, reinforcing glass fiber, and SBS elastomer.

[0015] Further, the sodium salt is selected from one of sodium carbonate, sodium sulfate, sodium bicarbonate, and sodium bisulfate; the chloride salt is selected from one of ferric chloride, copper chloride, barium chloride, and magnesium chloride.

[0016] Further, in the surface layer of the polylactic acid fiber, the dosage ratio of the second porous filler carrier, processing aid, and water-absorbing fiber is 5-10:1-5:30-100.

[0017] Further, in the first polylactic acid fiber layer, the dosage ratio of the sodium salt, second porous filler carrier, bamboo fiber, sodium alginate, processing aid, and water-absorbing fiber is 1-3:5-10:1-3:1-2:1-5:30-100; in the second polylactic acid fiber layer, the dosage ratio of the chloride salt, second porous filler carrier, bamboo fiber, sodium alginate, processing aid, and water-absorbing fiber is 1-3:5-10:1-3:1-2:1-5:30-100.

[0018] Further, through holes are provided in the degradable polylactic acid car floor mat.

[0019] The preparation method of the degradable polylactic acid car floor mat of the present invention includes:

[0020] Step 1: Prepare the polylactic acid fiber surface layer, the first polylactic acid fiber layer, the polylactic acid plastic film layer, the second polylactic acid fiber layer, and the polylactic acid resin bottom layer by molding for later use;

[0021] Step 2: First stack the first polylactic acid fiber layer, the polylactic acid plastic film layer, and the second polylactic acid fiber layer together and put them into a hot pressing device for one-time hot pressing and forming; then stack the polylactic acid fiber surface layer and the polylactic acid resin bottom layer on both sides respectively, and then put them into the hot pressing device again for secondary hot pressing and forming;

[0022] Step 3: Take out and cut according to requirements after cooling.

[0023] Further, in the step 1; the preparation of the polylactic acid plastic film layer includes: mixing polylactic acid resin, polystyrene, compatibilizer, the first porous carrier filler, and other additives, and then heating to 160-190 °C to make them blend evenly to obtain the first blend mixture; after cooling to 140-150 °C, adding titanium dioxide photosensitizer and continuing to mix evenly to obtain the second blend mixture; extruding the obtained second blend mixture through a screw extruder and forming to obtain a polylactic acid plastic film with a thickness of 0.5-1 mm.

[0024] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0025] 1. In the technical solution of the present invention, the foot mat body sequentially includes a polylactic acid fiber surface layer, a first polylactic acid fiber layer dispersed with sodium ions, a polylactic acid plastic film layer, a second polylactic acid fiber layer dispersed with chloride ions, and a polylactic acid resin bottom layer from top to bottom. Among them, the polylactic acid fiber surface layer and the polylactic acid resin bottom layer do not contain components that promote degradation, so that the foot mat has a long service life. After the surface layer and / or the bottom layer are damaged, the foot mat cannot be used continuously. After being discarded, the materials of the inner layer have components that can promote degradation, resulting in a relatively fast degradation rate.

[0026] 2. The present invention adds bamboo fiber and sodium alginate to the polylactic acid materials (the first polylactic acid fiber layer and the second polylactic acid fiber layer) for the foot mat to reduce the crystallinity of the polylactic acid composite material, thereby improving the degradability of the polylactic acid composite material.

[0027] 3. The present invention adopts a specific multi-layer structure, adding sodium salt and chloride salt to the polylactic acid composite materials on both sides of the polylactic acid plastic film layer respectively. During the degradation process, sodium chloride is generated by the reaction of the sodium salt and the chloride salt, and the presence of sodium chloride is used to increase the degradation rate of the subsequent polylactic acid material; at the same time, the sodium salt and the chloride salt are respectively added to the polylactic acid plastic film layer to avoid the contact reaction of the sodium salt and the chloride salt to generate sodium chloride during use, and to avoid reducing the service life due to the presence of sodium chloride.

[0028] 4. The present invention modifies montmorillonite with a silane coupling agent, which is beneficial to the dispersion of montmorillonite in polylactic acid. After being modified with the silane coupling agent, the intercalation and exfoliation effects of the montmorillonite filler are better. At the same time, montmorillonite as a filler can improve the mechanical properties such as the tensile strength, elongation at break, and impact strength of the polylactic acid material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the easily degradable polylactic acid foot mat of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] Example 1

[0032] An easily degradable polylactic acid car foot mat includes a foot mat body 1. The foot mat body 1 sequentially includes a polylactic acid fiber surface layer 101, a first polylactic acid fiber layer 102 dispersed with sodium ions, a polylactic acid plastic film layer 103, a second polylactic acid fiber layer 104 dispersed with chloride ions, and a polylactic acid resin bottom layer 105 from top to bottom.

[0033] Preparation method of biodegradable polylactic acid automotive floor mat, comprising:

[0034] Step 1, prepare a polylactic acid fiber surface layer 101, a first polylactic acid fiber layer 102, a polylactic acid plastic film layer 103, a second polylactic acid fiber layer 104 and a polylactic acid resin bottom layer 105;

[0035] Step 2, first stack the first polylactic acid fiber layer 102, the polylactic acid plastic film layer 103 and the second polylactic acid fiber layer 104 together, and put them into a hot pressing device for one-time hot pressing and forming; then stack the polylactic acid fiber surface layer 101 and the polylactic acid resin bottom layer 105 on both sides respectively, and then put them into the hot pressing device again for secondary hot pressing and forming;

[0036] Step 3, take out and cut according to requirements after cooling.

[0037] In step 1; the preparation of the polylactic acid plastic film layer 103 is as follows: mix polylactic acid resin, polystyrene, compatibilizer, first porous carrier filler and other auxiliaries, and then heat to 160 - 190 °C to make them blend evenly to obtain a first blend mixture; after cooling to 140 - 150 °C, add titanium dioxide photosensitizer and continue to mix evenly to obtain a second blend mixture; extrude the obtained second blend mixture through a screw extruder and form it into a polylactic acid plastic film.

[0038] The thickness of the polylactic acid plastic film layer 103 is 1 mm, and its raw materials are in parts by weight: 70 parts of polylactic acid resin, 40 parts of polystyrene, 1 part of titanium dioxide photosensitizer, 2 parts of compatibilizer, 1.5 parts of coupling agent, 2 parts of reinforcing glass fiber, 2 parts of SBS elastomer, and 12 parts of diatomite;

[0039] The first polylactic acid fiber layer 102 is made of 1.5 parts of sodium carbonate, 7 parts of porous ceramic alumina, 2 parts of bamboo fiber, 1 part of sodium alginate, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid in parts by weight. After mixing, disintegrating and dispersing, a mixed slurry is prepared, and then it is made by wet forming technology, and obtained after pressing and drying;

[0040] The second polylactic acid fiber layer 104 is made of 1.5 parts of magnesium chloride, 7 parts of porous ceramic alumina, 2 parts of bamboo fiber, 1 part of sodium alginate, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid in parts by weight. After mixing, disintegrating and dispersing, a mixed slurry is prepared, and then it is made by wet forming technology, and obtained after pressing and drying.

[0041] The polylactic acid resin bottom layer 105 is formed by injection molding of injection-grade polylactic acid resin.

[0042] The polylactic acid fiber surface layer 101 is obtained by mixing, defibrating, and dispersing 7 parts of porous ceramic alumina, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid by weight to prepare a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying.

[0043] Example 2

[0044] Different from Example 1, in Example 2:

[0045] The raw materials of the polylactic acid plastic film layer 103 are, by weight: 70 parts of polylactic acid resin, 40 parts of polystyrene, 1 part of titanium dioxide photosensitizer, 2 parts of compatibilizer, 1.5 parts of coupling agent, 2 parts of reinforcing glass fiber, 2 parts of SBS elastomer, and 12 parts of diatomite;

[0046] The first polylactic acid fiber layer 102 is obtained by mixing, defibrating, and dispersing 2.6 parts of sodium bicarbonate, 7 parts of porous ceramic alumina, 2 parts of bamboo fiber, 1 part of sodium alginate, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid by weight to prepare a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying;

[0047] The second polylactic acid fiber layer 104 is obtained by mixing, defibrating, and dispersing 1.3 parts of magnesium chloride, 7 parts of porous ceramic alumina, 2 parts of bamboo fiber, 1 part of sodium alginate, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid by weight to prepare a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying.

[0048] The polylactic acid resin bottom layer 105 is injection-molded from an injection-grade polylactic acid resin.

[0049] The polylactic acid fiber surface layer 101 is obtained by mixing, defibrating, and dispersing 7 parts of porous ceramic alumina, 1 part of antibacterial agent, 1 part of anti-ozone agent, and 60 parts of modified polylactic acid by weight to prepare a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying.

[0050] Example 3

[0051] Different from Example 1, in Example 3:

[0052] The raw materials of the polylactic acid plastic film layer 103 are, by weight: 70 parts of polylactic acid resin, 40 parts of polystyrene, 1 part of titanium dioxide photosensitizer, 2 parts of compatibilizer, 1.5 parts of coupling agent, 2 parts of reinforcing glass fiber, 2 parts of SBS elastomer, 12 parts of diatomite, and 15 parts of expanded graphite;

[0053] The first polylactic acid fiber layer 102 is prepared by mixing, defibrating and dispersing 2 parts by weight of sodium carbonate, 7 parts by weight of expanded graphite, 2 parts by weight of bamboo fiber, 1 part by weight of sodium alginate, 1 part by weight of antibacterial agent, 1 part by weight of anti-ozone agent, and 60 parts by weight of modified polylactic acid to obtain a mixed slurry, and then using the wet forming technology for papermaking, followed by pressing and drying.

[0054] The second polylactic acid fiber layer 104 is prepared by mixing, defibrating and dispersing 2 parts by weight of barium chloride, 7 parts by weight of expanded graphite, 2 parts by weight of bamboo fiber, 1 part by weight of sodium alginate, 1 part by weight of antibacterial agent, 1 part by weight of anti-ozone agent, and 60 parts by weight of modified polylactic acid to obtain a mixed slurry, and then using the wet forming technology for papermaking, followed by pressing and drying.

[0055] The polylactic acid resin bottom layer 105 is formed by injection molding of injection-grade polylactic acid resin.

[0056] The polylactic acid fiber surface layer 101 is prepared by mixing, defibrating and dispersing 7 parts by weight of porous ceramic alumina, 1 part by weight of antibacterial agent, 1 part by weight of anti-ozone agent, and 60 parts by weight of modified polylactic acid to obtain a mixed slurry, and then using the wet forming technology for papermaking, followed by pressing and drying.

[0057] Example 4

[0058] Differing from Example 1, in Example 4:

[0059] The raw materials of the polylactic acid plastic film layer 103 are as follows by weight: 60 parts of polylactic acid resin, 50 parts of polystyrene, 1.3 parts of titanium dioxide photosensitizer, 3 parts of compatibilizer, 6 parts of coupling agent, 7 parts of reinforcing glass fiber, 7 parts of SBS elastomer, and 16 parts of diatomite;

[0060] The first polylactic acid fiber layer 102 is prepared by mixing, defibrating and dispersing 3 parts by weight of sodium carbonate, 10 parts by weight of porous ceramic alumina, 3 parts by weight of bamboo fiber, 2 parts by weight of sodium alginate, 2 parts of antibacterial agent, 3 parts by weight of anti-ozone agent, and 100 parts by weight of modified polylactic acid to obtain a mixed slurry, and then using the wet forming technology for papermaking, followed by pressing and drying.

[0061] The second polylactic acid fiber layer 104 is prepared by mixing, defibrating and dispersing 3 parts by weight of magnesium chloride, 10 parts by weight of porous ceramic alumina, 3 parts by weight of bamboo fiber, 2 parts by weight of sodium alginate, 2 parts of antibacterial agent, 3 parts by weight of anti-ozone agent, and 100 parts by weight of modified polylactic acid to obtain a mixed slurry, and then using the wet forming technology for papermaking, followed by pressing and drying.

[0062] The polylactic acid resin bottom layer 105 is formed by injection molding of injection-grade polylactic acid resin.

[0063] The surface layer 101 of the polylactic acid fiber is prepared by mixing, defibrating and dispersing 1 part of porous ceramic alumina, 2 parts of antibacterial agent, 3 parts of anti-ozone agent and 100 parts of modified polylactic acid by weight, obtaining a mixed slurry, then using the wet forming technology for papermaking, and finally obtaining the product after pressing and drying.

[0064] Comparative Example 1

[0065] A degradable polylactic acid plastic, by weight, includes: 64 parts of polylactic acid resin, 42 parts of polystyrene, 1.1 parts of titanium dioxide photosensitizer, and 2.3 parts of compatibilizer. The preparation method is as follows: Mix the polylactic acid resin, polystyrene and compatibilizer, then heat to 160 - 170 °C to make them blend evenly to obtain the first blend mixture; after cooling to 140 - 150 °C, add the titanium dioxide photosensitizer and continue to mix evenly to obtain the second blend mixture; extrude and shape the obtained second blend mixture through a screw extruder.

[0066] Comparative Example 2

[0067] A degradable polylactic acid plastic, by weight, includes: 70 parts of polylactic acid resin, 33 parts of polystyrene, 1.1 parts of titanium dioxide photosensitizer, and 2.3 parts of compatibilizer. The preparation method is the same as that of Comparative Example 1.

[0068] For the above Examples 1 - 4 and Comparative Examples 1 - 2, the following experiments are set up to measure their properties;

[0069] Experiment 1: Measure the degradation rate of the above materials in the natural state. The specific measurement method is as follows: Follow the method in GB / T18006.2 - 1999 for the site steps. Make the plastics in the above examples and comparative examples into square plates with a side length of 16 cm 2 and a thickness of 5 mm, and disperse them in the above - mentioned measurement site. Observe daily, record the date when the mildew and deformation area on the sample surface reach more than 50% of the total sample area, record it as the mildew days, and record the date when the sample fragments, record it as the fragmentation days.

[0070] Experiment 2: First, place the sample under an ultraviolet lamp for treatment. During the treatment, the relative humidity is maintained at 30 - 50%, the power of the ultraviolet lamp is 60 w, and the treatment time is 6 h. After the treatment, measure and record the mildew days and fragmentation days according to the method in Experiment 1.

[0071] Experiment 3: First, place the sample under a solar simulator for treatment. The treatment time is 24 h, and the power of the solar simulator is 450 W. After the treatment, measure according to the method in Experiment 1 and record the mildew days and fragmentation days.

[0072]

[0073] From the above experiments, it can be seen that the foot pads prepared by the present invention can be degraded faster than the existing degradable polylactic acid plastics.

[0074] In the present invention, the addition of bamboo fiber and sodium alginate can improve the degradation of polylactic acid. Specifically, both bamboo fiber and sodium alginate can increase the mass loss rate of the polylactic acid composite material during the degradation process, and improve the degradability of the polylactic acid composite material by reducing the crystallinity of the polylactic acid composite material. In polylactic acid plastics, titanium dioxide photosensitizer can break the regular long-chain structure in the plastic and generate many small cracks, which helps the subsequent biodegradation. During the degradation of the foot pads of the present invention, when the internal polylactic acid plastic film layer 103 is degraded, sodium ions in the first polylactic acid fiber layer 102 react with chloride ions in the second polylactic acid fiber layer 104 to generate sodium chloride, which can provide a promoting effect on the degradation of polylactic acid.

[0075] In the present invention, through the polylactic acid fiber surface layer 101 and the polylactic acid resin bottom layer 105 that do not contain bamboo fiber and sodium alginate, the presence of bamboo fiber and sodium alginate is avoided. When the foot pad contacts water or an environment of acid, alkali, or salt during use, the polylactic acid fiber surface layer 101 and the polylactic acid resin bottom layer 105 will not degrade rapidly, thus affecting the service life.

[0076] For some products of Examples 1-4, 4 small holes with a diameter of 0.2 cm were evenly opened on a square plate using a punching device, and were respectively marked as Control 1, Control 2, Control 3, and Control 4, and then Experiments 1, 2, and 3 were carried out in sequence.

[0077]

[0078] By opening holes in the square plate, the sodium ions in the first polylactic acid fiber layer 102 and the chloride ions in the second polylactic acid fiber layer 104 can complete the contact reaction earlier during the degradation process to generate sodium chloride, so as to release sodium chloride in advance during the degradation process, and then use the presence of sodium chloride to overall increase the degradation rate. The experiment also proves that after punching, the degradation speed of the material is improved.

[0079] After the foot pads of the present invention are used for a long time, when the polylactic acid fiber surface layer 101 and / or the polylactic acid resin bottom layer 105 are damaged, the foot pads can be discarded at this time. When the discarded foot pads are in a humid environment, the first polylactic acid fiber layer 102 and the second polylactic acid fiber layer 104 will degrade first, releasing the bamboo fiber and sodium alginate they contain to accelerate hydrolysis; when the polylactic acid plastic film layer 103 in the middle starts to degrade and destroys its own structure, the sodium ions in the first polylactic acid fiber layer 102 and the chloride ions in the second polylactic acid fiber layer 104 complete the contact reaction to generate sodium chloride, thereby increasing the overall degradation speed.

[0080] In the present invention, by setting that the materials and compositions of each layer structure are different, during actual use, the polylactic acid fiber surface layer 101 and the polylactic acid resin bottom layer 105 are utilized to contact the first polylactic acid fiber layer 102 and the second polylactic acid fiber layer 104 located inside thereof with moisture and the like, so as to avoid non-demand degradation caused by being placed in a humid environment with a large number of microorganisms during use.

[0081] In the present invention, the modified polylactic acid is obtained by first using a silane coupling agent as a modifier to modify montmorillonite to obtain organically modified montmorillonite; then mixing the obtained organically modified montmorillonite with polylactic acid. In the present invention, montmorillonite is modified by a silane coupling agent and then polylactic acid is modified to obtain modified polylactic acid, which is beneficial to the dispersion of montmorillonite in polylactic acid. After being modified by a silane coupling agent, the intercalation and exfoliation effects of the montmorillonite filler are better. At the same time, montmorillonite as a filler can improve the mechanical properties of polylactic acid materials such as tensile strength, elongation at break, and impact strength.

[0082] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, according to the content of this specification, many modifications and changes can be made. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A biodegradable polylactic acid car floor mat, characterized in that: It includes a foot mat body (1), and the foot mat body (1) sequentially includes a polylactic acid fiber surface layer (101), a first polylactic acid fiber layer (102) dispersed with sodium ions, a polylactic acid plastic film layer (103), a second polylactic acid fiber layer (104) dispersed with chloride ions, and a polylactic acid resin bottom layer (105) from top to bottom; Among them, the thickness of the polylactic acid plastic film layer (103) is 0.5 - 1 mm, and its raw material components by weight include: 60 - 70 parts of polylactic acid resin, 33 - 50 parts of polystyrene, 0.6 - 1.3 parts of titanium dioxide photosensitizer, 1.5 - 3 parts of compatibilizer, 1 - 20 parts of other additives, and 9 - 16 parts of a first porous filler carrier; Among them, the first polylactic acid fiber layer (102) is obtained by mixing and defibrating and dispersing the solid powders of sodium salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying; Among them, the second polylactic acid fiber layer (104) is obtained by mixing and defibrating and dispersing the solid powders of chloride salt, a second porous filler carrier, bamboo fiber, sodium alginate, and processing aids with water-absorbing fibers to obtain a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying; Among them, the polylactic acid resin bottom layer (105) is injection-molded from injection-grade polylactic acid resin.

2. The biodegradable polylactic acid car floor mat according to claim 1, wherein, The polylactic acid fiber surface layer (101) is obtained by mixing and defibrating and dispersing the solid powders of a second porous filler carrier and processing aids with water-absorbing fibers to obtain a mixed slurry, and then using a wet forming technique to make a sheet, followed by pressing and drying.

3. The biodegradable polylactic acid car floor mat according to claim 2, characterized in that, In the polylactic acid fiber surface layer (101), the first polylactic acid fiber layer (102), and the second polylactic acid fiber layer (104), the water-absorbing fiber is modified polylactic acid; the modified polylactic acid is obtained by first modifying montmorillonite with an organic quaternary ammonium salt, alkyl amino acid, polymer monomer, or coupling agent as a modifier to obtain organically modified montmorillonite, and then mixing the organically modified montmorillonite with polylactic acid.

4. A degradable polylactic acid automotive floor mat according to claim 1, 2 or 3, characterized in that The first porous filler carrier is diatomite, bentonite, porous ceramic alumina, or expanded graphite; the second porous filler carrier is porous ceramic alumina or expanded graphite.

5. An easily degradable polylactic acid car floor mat according to claim 1, 2 or 3, characterized in that, The other additives include one or more of coupling agent, reinforcing glass fiber, and SBS elastomer.

6. The biodegradable polylactic acid automotive floor mat according to claim 1, 2 or 3, characterized in that, The processing aids include one or more of antibacterial agent, anti-ozone agent, coupling agent, reinforcing glass fiber, and SBS elastomer.

7. An easily degradable polylactic acid automotive floor mat according to claim 1, 2 or 3, characterized in that, The sodium salt is selected from one of sodium carbonate, sodium sulfate, sodium bicarbonate, and sodium bisulfate; the chloride salt is selected from one of ferric chloride, copper chloride, barium chloride, and magnesium chloride.

8. An easily degradable polylactic acid automotive floor mat according to claim 1, 2 or 3, characterized in that, In the polylactic acid fiber surface layer (101), the dosage ratio of the second porous filler carrier, processing aids, and water-absorbing fiber is 5 - 10:1 - 5:30 - 100.

9. A biodegradable polylactic acid automotive foot mat according to claim 1, 2 or 3, characterized in that, In the first polylactic acid fiber layer (102), the dosage ratio of sodium salt, the second porous filler carrier, bamboo fiber, sodium alginate, processing aid, and water-absorbing fiber is 1-3:5-10:1-3:1-2:1-5:30-100; in the second polylactic acid fiber layer (104), the dosage ratio of chloride salt, the second porous filler carrier, bamboo fiber, sodium alginate, processing aid, and water-absorbing fiber is 1-3:5-10:1-3:1-2:1-5:30-100.

10. The preparation method of the biodegradable polylactic acid car floor mat according to claim 1, characterized in that, Including: Step 1, prepare the polylactic acid fiber surface layer (101), the first polylactic acid fiber layer (102), the polylactic acid plastic film layer (103), the second polylactic acid fiber layer (104), and the polylactic acid resin bottom layer (105) for molding and standby; Step 2, first stack the first polylactic acid fiber layer (102), the polylactic acid plastic film layer (103), and the second polylactic acid fiber layer (104) together and put them into a hot pressing device for one-time hot pressing and molding; then stack the polylactic acid fiber surface layer (101) and the polylactic acid resin bottom layer (105) on both sides respectively, and then put them into the hot pressing device again for secondary hot pressing and molding; Step 3, take out and cut according to requirements after cooling.

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