Modified polylactic acid material

Abstract

The present application discloses a modified polylactic acid material, which, by weight parts, comprises the following raw material components: 65-90 parts of polylactic acid; 5-30 parts of modified particles; 0-5 parts of compatibilizer; 0-5 parts of toughening agent; the modified particles include inorganic particles and crude dimer acid wrapped on the surface of the inorganic particles. The present application combines modified particles with toughening function and polylactic acid, and they have good compatibility. When applied to the preparation of polylactic acid materials, the use performance can be improved.

Description

Technical Field

[0001] This application relates to the technical field of polymer materials, and particularly to a modified polylactic acid material. Background Art

[0002] Polylactic acid (PLA) is made from biomass raw materials through fermentation and polymerization, and is a biodegradable and environmentally friendly thermoplastic resin. Although PLA has relatively high tensile strength and flexural strength, its brittleness, poor toughness, and small elongation at break limit the application of polylactic acid.

[0003] Currently, the common methods for modifying PLA mainly include copolymerization modification and blending modification. Among them, the copolymerization modification method fundamentally improves the brittleness of PLA by regulating the molecular structure, but this modification method has problems such as complex preparation process and high cost. The blending method is to improve the performance of PLA by adding plasticizers or elastomers to blend with PLA. For example, the bio-based thermoplastic vulcanizate added in Patent CN202011284429.X, the modified carboxyl butadiene rubber added in Patent CN202210440720.4, and the modified epoxidized vegetable oil added in Patent CN202210031930.8 can all be blended with poly-PLA as plasticizers to improve the performance of the product; however, these methods have problems such as the migration of plasticizers due to poor compatibility with the matrix, or the elastomers are difficult to biodegrade and sacrifice the tensile properties of polylactic acid. Summary of the Invention

[0004] In view of the problems in the prior art, this application provides a modified polylactic acid material with excellent performance.

[0005] The modified polylactic acid material provided by this application, in parts by weight, comprises the following raw material components:

[0006]

[0007] The modified particles include inorganic particles and dimer acid wrapped on the surface of the inorganic particles.

[0008] Optionally, the hydrophobic contact angle of the modified particles is 74° - 82°, and the average particle size is 1 - 2 μm. It has good lipophilic-hydrophobic properties and good structural stability.

[0009] Optionally, the loading amount of dimer acid in the modified particles is 1 - 5 wt%, preferably 1 - 3 wt%, and more preferably 2 wt%. The dimer acid improves the surface polarity of the inorganic particles, making the dispersibility and compatibility of the modified particles in polylactic acid better, thereby enhancing the toughness of polylactic acid.

[0010] Optionally, the molecular weight of the polylactic acid is 60000 - 130000.

[0011] Optionally, the inorganic particles are at least one of calcium carbonate, montmorillonite, talc powder, mica, and titanium dioxide; preferably talc powder and / or montmorillonite; more preferably talc powder.

[0012] Optionally, the compatibilizer is at least one of SBS-g-MAH, KH550, and SEBS. Preferably KH550.

[0013] Optionally, the toughening agent is at least one of EPDM, POE, and epoxidized soybean oil.

[0014] Optionally, the preparation method of the modified particles comprises the following steps:

[0015] Mix crude dimer acid, inorganic particles, and a solvent for reaction;

[0016] After the reaction ends, wash and dry the product to obtain the modified particles.

[0017] See Figure 1 , the combination of crude dimer acid and inorganic particles is a chemical reaction. The crude dimer acid is dissolved in the solvent and adsorbed on the surface of the inorganic particles through electrostatic attraction. Subsequently, a chemical reaction occurs between the carboxyl group of the crude dimer acid and the hydroxyl group on the surface of the inorganic particles to form a chemical bond, thereby forming stable hybrid modified particles.

[0018] Crude dimer acid is generally an industrial by-product, usually referring to a mixture of monomers, dimers, and trimers that cannot be separated and purified during the production of dimer acid; this mixture generally includes unsaturated monocarboxylic acids, dimer acids, and trimer acids with 18 carbon atoms; among them, dimer acid is a dicarboxylic acid formed by the reaction of two or more C18 unsaturated fatty acids. Trimer acid is a tricarboxylic acid formed by the reaction of three or more C18 unsaturated fatty acids.

[0019] More specifically, for example, crude dimer acid is an unpurified mixture obtained by reacting unsaturated monocarboxylic acids with 18 carbon atoms such as soya-bean oleic acid, cottonseed oleic acid, rice bran oleic acid, or tall oil fatty acid, etc. under the catalysis of clay, montmorillonite, etc., and mainly includes about 75% of dimer acid isomers (C36), as well as a small amount of saturated and unsaturated monocarboxylic acids (C18, about 1.5%), and some trimer acids (C54, about 23.5%).

[0020] Optionally, the content of the C18 unsaturated dimer acid in the crude dimer acid is not less than 75 wt%. Preferably 75 - 85 wt%.

[0021] Optionally, the mass ratio of the inorganic particles to the crude dimer acid is 50 - 10:1, preferably 40 - 20:1, more preferably 30:1.

[0022] Optionally, the solvent is at least one of ethanol, tetrahydrofuran, and acetonitrile. Ethanol is preferred.

[0023] Optionally, the mass ratio of the solvent to the inorganic particles is 50-5:1, preferably 10-5:1.

[0024] Optionally, the temperature of the reaction is 25-60 °C, preferably 60 °C.

[0025] Optionally, the reaction time is 0.5-2 h, preferably 2 h.

[0026] Optionally, the reagent used for cleaning is ethanol.

[0027] Optionally, the drying conditions are: vacuum, 60 °C; the drying time is 6-12 h.

[0028] Optionally, the toughening agent is at least one of EPDM, POE, and epoxy soybean oil. EPDM and / or POE are preferred.

[0029] Optionally, by weight, the modified polylactic acid material comprises the following raw material components:

[0030] Polylactic acid 70-75;

[0031] Modified particles 20-25;

[0032] Compatibilizer 2-5;

[0033] Toughening agent 2-5.

[0034] Optionally, each component is blended to obtain a polylactic acid composition, which can be used to prepare a modified polylactic acid material.

[0035] The above-mentioned polylactic acid composition may further include other components. Of course, depending on different application requirements, it may also consist only of the above several components.

[0036] Various modified polylactic acid materials, such as polylactic acid particles, can be prepared using the polylactic acid composition. The addition amount of the modified particles in the polylactic acid composition affects the impact strength and elongation at break of the polylactic acid material, etc.

[0037] In the examples, the preparation method of the modified polylactic acid material includes: mixing the raw materials and then granulating. The granulation method is extrusion granulation. After granulation, the particles need to be cleaned and dried to obtain dry modified particles for subsequent applications. The temperature of the extrusion granulation is 160-200 °C.

[0038] Compared with the prior art, the present application has the following technical effects:

[0039] This application combines modified particles with toughening function and polylactic acid. They have good compatibility, and at the same time improve the toughness and mechanical strength of the product.

[0040] This application uses industrial by-product crude dimer acid solution to prepare modified particles. The process is simple, the reaction is mild, and it is easy to industrialize production. Brief Description of the Drawings

[0041] Figure 1 is the schematic diagram for preparing modified particles in this application;

[0042] Figure 2 is the electron microscope image of modified talc powder;

[0043] Figure 3 is the thermogravimetric curve of modified talc powder and talc powder;

[0044] Figure 4 is the DSC diagram of modified talc powder;

[0045] Figure 5 is the diagram showing the influence of filling with 0, 5, 10, 15, 20, 25 and 30 wt% modified particles on the notched impact strength of polylactic acid material;

[0046] Figure 6 is the diagram showing the influence of filling with 0, 5, 10, 15, 20, 25 and 30 wt% modified particles on the elongation at break of polylactic acid material. Detailed Embodiments

[0047] The following further describes the technical solutions of this application in combination with specific embodiments, but this application is not limited thereto.

[0048] The reagents used in each example and comparative example are all commercially available. Among them, Shandong Xuchen Chemical Technology Co., Ltd. and Shanghai Gaoming Chemical Co., Ltd.; the polylactic acid comes from Nature Work Company in the United States, with the model number 4032D.

[0049] Example 1

[0050] Prepare modified particles: After diluting crude dimer acid 30 - 100 times with ethanol, mix it evenly with talc powder, and stir and react at room temperature for 2 h. After the reaction, wash and centrifuge three times, and then dry in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of talc powder to crude dimer acid is 30:1.

[0051] Prepare polylactic acid material: By weight, mix 5 parts of modified particles, 90 parts of polylactic acid and 5 parts of compatibilizer KH550 evenly to obtain a mixture, and extrude and pelletize the mixture. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0052] Example 2

[0053] Prepare modified particles according to the method of Example 1. Mix 10 parts of modified particles, 85 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0054] Example 3

[0055] Prepare modified particles according to the method of Example 1. Mix 15 parts of modified particles, 80 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0056] Example 4

[0057] Prepare modified particles according to the method of Example 1. Mix 20 parts of modified particles, 75 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0058] Example 5

[0059] Prepare modified particles according to the method of Example 1. Mix 25 parts of modified particles, 70 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0060] Example 6

[0061] Prepare modified particles according to the method of Example 1. Mix 30 parts of modified particles, 65 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0062] Example 7

[0063] Dilute crude dimer acid 30 - 100 times with acetonitrile, then mix it evenly with montmorillonite, and stir and react at 60 °C for 30 min. After the reaction, wash and centrifuge three times, and then dry in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of montmorillonite to dimer acid is 40:1.

[0064] Mix 5 parts of modified particles, 90 parts of polylactic acid, and 5 parts of toughening agent EPDM evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0065] Example 8

[0066] After diluting crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with calcium carbonate, then crude dimer acid is added and mixed evenly, and the mixture is stirred and reacted at 60°C for 30 min. After the reaction, it is washed and centrifuged three times, and then dried in a vacuum oven at 60°C for 6 h to obtain modified particles. The mass ratio of calcium carbonate to crude dimer acid is 50:1.

[0067] Mix 10 parts of modified particles, 80 parts of polylactic acid, 5 parts of compatibilizer SBS-g-MAH, and 5 parts of toughening agent POE evenly to obtain a mixture. Extrude and pelletize the mixture, and the temperature of the extrusion screw is 160 - 200°C to obtain a modified polylactic acid material.

[0068] Example 9

[0069] After diluting crude dimer acid 30 - 100 times with tetrahydrofuran, it is mixed evenly with mica, and stirred and reacted at room temperature for 1 h. After the reaction, it is washed and centrifuged three times, and then dried in a vacuum oven at 60°C for 6 h to obtain modified particles. The mass ratio of mica to crude dimer acid is 30:1.

[0070] Mix 25 parts of modified particles, 70 parts of polylactic acid, 2 parts of compatibilizer KH550, and 3 parts of toughening agent epoxidized soybean oil evenly to obtain a mixture. Extrude and pelletize the mixture, and the temperature of the extrusion screw is 160 - 200°C to obtain a modified polylactic acid material.

[0071] Example 10

[0072] After diluting crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with calcium carbonate, and stirred and reacted at 60°C for 2 h. After the reaction, it is washed and centrifuged three times, and then dried in a vacuum oven at 60°C for 6 h to obtain modified particles. The mass ratio of calcium carbonate to dimer acid is 30:1.

[0073] Mix 25 parts of modified particles and 75 parts of polylactic acid evenly to obtain a mixture. Extrude and pelletize the mixture, and the temperature of the extrusion screw is 160 - 200°C to obtain a modified polylactic acid material.

[0074] Example 11

[0075] After diluting crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with calcium carbonate, and stirred and reacted at room temperature for 2 h. After the reaction, it is washed and centrifuged three times, and then dried in a vacuum oven at 60°C for 6 h to obtain modified particles. The mass ratio of calcium carbonate and crude dimer acid is 30:1.

[0076] Mix 25 parts of modified particles, 70 parts of polylactic acid, and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Extrude and pelletize the mixture, and the temperature of the extrusion screw is 160 - 200°C to obtain a modified polylactic acid material.

[0077] Example 12

[0078] After diluting the crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with montmorillonite, and the reaction is stirred at room temperature for 2 h. After the reaction is completed, it is washed and centrifuged three times, and then dried in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of montmorillonite to crude dimer acid is 30:1.

[0079] 25 parts of the modified particles, 70 parts of polylactic acid and 5 parts of compatibilizer KH550 are mixed evenly to obtain a mixture, and the mixture is extruded and granulated. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0080] Example 13

[0081] After diluting the crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with mica, and the reaction is stirred at room temperature for 2 h. After the reaction is completed, it is washed and centrifuged three times, and then dried in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of mica to crude dimer acid is 30:1.

[0082] 25 parts of the modified particles, 70 parts of polylactic acid and 5 parts of compatibilizer KH550 are mixed evenly to obtain a mixture, and the mixture is extruded and granulated. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0083] Example 14

[0084] After diluting the crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with titanium dioxide, and the reaction is stirred at room temperature for 2 h. After the reaction is completed, it is washed and centrifuged three times, and then dried in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of titanium dioxide to crude dimer acid is 30:1.

[0085] 25 parts of the modified particles, 70 parts of polylactic acid and 5 parts of compatibilizer KH550 are mixed evenly to obtain a mixture, and the mixture is extruded and granulated. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0086] Example 15

[0087] After diluting the crude dimer acid 30 - 100 times with ethanol, it is mixed evenly with talcum powder, and the reaction is stirred at room temperature for 2 h. After the reaction is completed, it is washed and centrifuged three times, and then dried in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of talcum powder to crude dimer acid is 10:1.

[0088] 25 parts of the modified particles, 70 parts of polylactic acid and 5 parts of compatibilizer KH550 are mixed evenly to obtain a mixture, and the mixture is extruded and granulated. The temperature of the extrusion screw is 160 - 200 °C to obtain the modified polylactic acid material.

[0089] Comparative Example 1

[0090] Mix 95 parts of polylactic acid and 5 parts of compatibilizer KH550 evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain a polylactic acid material.

[0091] Comparative Example 2

[0092] Dilute stearic acid 30 - 100 times with ethanol, then mix it evenly with calcium carbonate, and stir and react at 60 °C for 2 h. After the reaction, wash and centrifuge three times, and then dry in a vacuum oven at 60 °C for 6 h to obtain modified particles. The mass ratio of calcium carbonate to stearic acid is 30:1.

[0093] Mix 25 parts of modified particles and 75 parts of polylactic acid evenly to obtain a mixture. Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain a polylactic acid material.

[0094] Comparative Example 3

[0095] Mix 25 parts of elastomer POE and 75 parts of polylactic acid evenly to obtain a mixture;

[0096] Granulate the mixture by extrusion. The temperature of the extrusion screw is 160 - 200 °C to obtain a polylactic acid material.

[0097] See Figure 2 , observe the microscopic morphology of the modified particles prepared in Example 5 by scanning electron microscopy. The average particle size of the modified particles is 1 - 2 μm.

[0098] See Figure 3 , from the thermogravimetric curves of the modified talc powder and talc powder in Example 1, it can be seen that the loading amount of crude dimer acid in the modified particles is about 2 wt%. See Figure 4 , compared with pure polylactic acid, the crystallinity of the modified polylactic acid material filled with modified talc powder is higher, and the melting point is increased by about 3 °C. Similarly, the loading amount of crude dimer acid in the modified talc powder of Example 15 is measured to be 5 wt%.

[0099] Test the tensile strength, elongation at break, notched impact strength and Vicat heat distortion temperature of the polylactic acid particles in Examples 1 - 15 and Comparative Examples 1 - 3. See Figure 5 、 6 , compared with Comparative Example 1, the notched impact strength and elongation at break of the modified polylactic acid materials prepared in Examples 1 - 6 increase with the increase of the filling amount of the modified particles, and both reach the maximum at 25 wt%, and slightly decrease at 30 wt%. This is because too much filling amount leads to particle agglomeration, resulting in a worse toughening effect.

[0100] See Table 1:

[0101] Table 1 Performance test results

[0102]

[0103]

[0104] As can be seen from the results in Table 1, compared with Comparative Example 1, the polylactic acid particles prepared in Example 5 retain the tensile strength of pure polylactic acid (PLA), while improving the toughness and heat distortion temperature of the product. Although the impact toughness of Comparative Example 3 is greatly improved, the tensile strength and heat distortion temperature decrease. Compared with Comparative Example 2, after adding inorganic particles modified with crude dimer acid to PLA in Examples 5, 7 to 10, the toughness of PLA can be better improved, and other properties can be maintained or enhanced, and Example 5 has the best comprehensive performance. As can be seen from Examples 5, 11 to 14, under the same conditions, the phenolic resin material prepared with talc as the inorganic particle has better performance. As can be seen from Example 5 and Example 15, under the same conditions, the phenolic resin material filled with 2wt% of crude dimer acid modified talc has the best performance.

[0105] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use this application. Those skilled in the art to which this application pertains can also make appropriate changes and modifications to the above embodiments. Therefore, this application is not limited to the specific embodiments disclosed and described above, and some modifications and changes to this application should also fall within the protection scope of the claims of this application.

Claims

1. A modified polylactic acid material, characterized in that, Comprising the following raw material components by weight parts: Polylactic acid 65 - 90; Modified particles 5 - 30; Compatibilizer 0 - 5; Toughening agent 0 - 5; The modified particles include inorganic particles and crude dimer acid wrapped on the surface of the inorganic particles; The combination of the crude dimer acid and the inorganic particles is a chemical reaction to form chemical bonds.

2. The modified polylactic acid material according to claim 1, wherein The hydrophobic contact angle of the modified particles is 74° - 82°, and the average particle size is 1 - 2 μm.

3. The modified polylactic acid material according to claim 1, characterized in that The loading amount of the crude dimer acid in the modified particles is 1 - 5 wt%.

4. The modified polylactic acid material according to claim 1, wherein The molecular weight of the polylactic acid is 60000 - 130000.

5. The modified polylactic acid material according to claim 1, characterized in that, The inorganic particles are at least one of calcium carbonate, montmorillonite, talcum powder, mica and titanium dioxide; The compatibilizer is at least one of SBS-g-MAH, KH550 and SEBS; The toughening agent is at least one of EPDM, POE and epoxidized soybean oil.

6. The modified polylactic acid material according to claim 1, wherein The preparation method of the modified particles comprises the following steps: Mix the crude dimer acid, inorganic particles and solvent for reaction; After the reaction ends, wash and dry the product to obtain the modified particles.

7. The modified polylactic acid material according to claim 6, wherein The mass ratio of the inorganic particles to the crude dimer acid is 50 - 10:

1.

8. The modified polylactic acid material according to claim 6, characterized in that, The mass ratio of the solvent to the inorganic particles is 50 - 5:1; The solvent is at least one of ethanol, tetrahydrofuran and acetonitrile.

9. The modified polylactic acid material according to claim 6, wherein The temperature of the reaction is 25 - 60°C, and the time is 0.5 - 2 h.

10. The modified polylactic acid material according to claim 1, characterized in that, Comprising the following raw material components by weight parts: Polylactic acid 70 - 75; Modified particles 20 - 25; Compatibilizer 2 - 5; Toughening agent 2 - 5.

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