A natural antioxidant composite diacetate cellulose particle and a method for preparing the same

Abstract

The application discloses natural antioxidant composite diacetate cellulose glue particles and a preparation method thereof, and relates to the technical field of high polymer materials, which comprises diacetate cellulose, plasticizer and natural antioxidant; wherein, according to weight parts, the diacetate cellulose is 59.5-79.9 parts; the plasticizer is 20-40 parts; the natural antioxidant is 0.1-0.5 parts; the plasticizer is phthalate plasticizer or environment-friendly non-phthalate plasticizer; and the glue particles are prepared based on the above formula. The antioxidant adopted in the application is environment-friendly, non-toxic, widely-sourced and stably-supplied, and has excellent antioxidant effect, and the smell of the antioxidant helps to relieve fatigue, so that the prepared diacetate cellulose glue particles are environment-friendly, and the obtained glue particles are transparent, and the mechanical properties, water absorption and plasticizer migration performance of the glue particles are equivalent to those of traditional phthalate materials, the glue particles are safe for human health, and the glue particles can replace traditional materials to be applied in the fields of spectacle plate materials, tool handles and adhesive tapes.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a natural antioxidant composite cellulose diacetate granule and its preparation method. Background Technology

[0002] Cellulose acetate is a thermoplastic resin prepared by the esterification reaction of cellulose and acetic anhydride. It has attracted widespread attention due to its high transparency, good toughness, and ease of molding and processing. Based on the degree of substitution of the hydroxyl groups in the acetyl groups of the cellulose molecule, cellulose acetate can be classified into monoacetate, diacetate, and triacetate, with degrees of substitution of 1.72–1.95, 2.22–2.76, and 2.76–3.03, respectively. Different degrees of substitution endow cellulose acetate with different properties, making it more widely used in tobacco, eyeglass frames, biomedicine, automotive electronics, and other fields.

[0003] Commonly used synthetic antioxidants such as phenols and amines are widely applied in plastic products, electronic devices, food packaging, and pharmaceuticals. However, because antioxidants are not covalently bound to the matrix, they easily migrate into the environment, causing pollution. Therefore, in the food packaging sector, antioxidants can migrate into food and be ingested, having been proven to be hepatotoxic, endocrine disruptive, and carcinogenic. They have also been detected in various environmental media, including indoor dust, outdoor airborne particulate matter, marine sediments, and river water, posing a significant threat to human health. Natural antioxidants, derived from plants, animals, and other natural substances, possess advantages such as high activity, no chemical synthesis residues, and low toxicity. They have a strong ability to scavenge free radicals and are commonly used in the food, cosmetics, and pharmaceutical industries. Furthermore, after degradation, they are harmless to soil and humans. In addition, some natural antioxidants not only have antibacterial and preservative properties but also possess a refreshing plant scent, helping to relieve fatigue and improve mental state. Therefore, replacing traditional synthetic antioxidants used in cellulose diacetate materials with natural antioxidants is a new trend in traditional plastic antioxidants.

[0004] For example, Chinese patent (CN109503892A) discloses a cellulose diacetate material, which uses cellulose diacetate granules with added synthetic antioxidants. This limits the material to eyeglass frame materials because its application to food contact materials such as food packaging could pose a potential health hazard. Therefore, the added natural antioxidants need to be biodegradable without reducing the original antioxidant effect, and also harmless to the environment and human body. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a natural antioxidant composite cellulose diacetate granules and its preparation method, thereby solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a natural antioxidant composite cellulose diacetate granules, comprising cellulose diacetate, a plasticizer, and a natural antioxidant; By weight: Cellulose diacetate content was 59.5–79.9 parts. The amount of plasticizer is 20-40 parts; The amount of natural antioxidant is 0.1 to 0.5 parts; The plasticizer is a phthalate plasticizer or an environmentally friendly non-phthalate plasticizer.

[0007] To further optimize this technical solution, the cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.

[0008] To further optimize this technical solution, when the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.

[0009] To further optimize this technical solution, when the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.

[0010] To further optimize this technical solution, the natural antioxidant is one or more of the following: fat-soluble rosemary extract, fat-soluble tea polyphenols, vitamin E, L-ascorbyl palmitate, sesaminol, sesamolin, astaxanthin, and quercetin.

[0011] A method for preparing natural antioxidant composite cellulose diacetate particles, based on the above-mentioned natural antioxidant composite cellulose diacetate particles, includes the following steps: S1. Construct a natural antioxidant plasticizing system; S2. Add cellulose diacetate and mix evenly for maturation; S3. Melt plasticizing treatment based on extrusion equipment; S4. Extrusion molding and granule preparation; S5. Drying process and obtaining the finished product.

[0012] To further optimize this technical solution, in step S1, a natural antioxidant is added to the plasticizer and mechanically stirred for 30 minutes at room temperature to ensure that the natural antioxidant is fully dissolved or uniformly dispersed in the plasticizer, thus forming a natural antioxidant plasticizing system.

[0013] To further optimize this technical solution, in step S2, the natural antioxidant plasticizer system is added to cellulose diacetate and mixed evenly for 40 minutes. After mixing, the resulting mixture is aged at room temperature for 12 to 36 hours.

[0014] To further optimize this technical solution, in step S3, a twin-screw extruder is used for processing, and gradient temperature control is implemented for each temperature zone of the extruder. The temperature zones from the feed inlet to the die head are set sequentially to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃ and 230℃, with the die head temperature controlled at 230℃.

[0015] To further optimize this technical solution, in step S4, the extrusion strip is rapidly cooled and solidified by water cooling or air cooling to obtain a stable solid strip material. Then, the cooled material is cut and granulated by a pelletizing device to form a uniform particle structure.

[0016] Compared with the prior art, the present invention provides a natural antioxidant composite cellulose diacetate granules and its preparation method, which has the following beneficial effects: This natural antioxidant composite cellulose diacetate granules and its preparation method utilize an environmentally friendly, non-toxic, widely available, and stably supplied antioxidant with excellent antioxidant effects. Its odor helps relieve fatigue, resulting in environmentally friendly cellulose diacetate granules that are transparent, with mechanical properties, water absorption, and plasticizer migration properties comparable to traditional phthalate materials. They are safe for human health and can replace traditional materials in applications such as eyeglass sheets, tool handles, and tapes. Furthermore, their applications can be expanded to food packaging, medical and health fields. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a method for preparing natural antioxidant composite cellulose diacetate granules proposed in this invention. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0022] A natural antioxidant compound cellulose diacetate granules, comprising cellulose diacetate, plasticizer, and natural antioxidant.

[0023] By weight: Cellulose diacetate content was 59.5–79.9 parts. The amount of plasticizer is 20-40 parts; The amount of natural antioxidant is 0.1 to 0.5 parts.

[0024] The cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.

[0025] The natural antioxidant is one or more of the following: fat-soluble rosemary extract, fat-soluble tea polyphenols, vitamin E, L-ascorbyl palmitate, sesaminol, sesamolin, astaxanthin, and quercetin.

[0026] The plasticizer is a phthalate plasticizer or an environmentally friendly non-phthalate plasticizer.

[0027] When the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.

[0028] When the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.

[0029] Reference Figure 1A method for preparing natural antioxidant composite cellulose diacetate particles, based on the above-mentioned natural antioxidant composite cellulose diacetate particles, includes the following steps: S1. Construct a natural antioxidant plasticizing system.

[0030] Specifically, natural antioxidants are added to plasticizers and mechanically stirred for 30 minutes at room temperature to ensure that the natural antioxidants are fully dissolved or evenly dispersed in the plasticizer, forming a natural antioxidant plasticizing system.

[0031] If the natural antioxidant is fat-soluble, it is dissolved completely in the plasticizer system through continuous stirring. If the natural antioxidant is poorly soluble or slightly soluble, the stirring time is extended and the shear force is increased to form a stable, finely dispersed state. This step ensures a stable distribution of the natural antioxidant in the plasticizer, thus preventing local enrichment or precipitation of the antioxidant during subsequent processing and improving its dispersion uniformity and stability in the cellulose diacetate system.

[0032] S2. Add cellulose diacetate and mix evenly for maturation.

[0033] Specifically, the natural antioxidant plasticizer system is added to cellulose diacetate and mixed evenly for 40 minutes. After mixing, the resulting mixture is aged at room temperature for 12 to 36 hours.

[0034] During the curing process, the plasticizer gradually penetrates into the gaps between the cellulose diacetate molecular chains, forming a stable plasticized structure inside the material. At the same time, the natural antioxidants are evenly distributed inside the material along with the plasticizer, thereby improving the stability of the system during subsequent melt processing.

[0035] S3. Melt plasticization treatment based on extrusion equipment.

[0036] Specifically, a twin-screw extruder is used for processing, and the temperature of each zone of the extruder is controlled by gradient temperature rise. The temperature zones from the feed inlet to the die are set sequentially to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃ and 230℃, with the die temperature controlled at 230℃.

[0037] During extrusion, cellulose diacetate gradually melts and plasticizes under heat and shear, forming a homogeneous melt composite system with plasticizers and natural antioxidants. Through the conveying, compression, and mixing action of the screw, the natural antioxidants are further uniformly dispersed in the melt and form a stable bond with the cellulose diacetate molecular chains, thereby ensuring the antioxidant properties and material stability of the final granules.

[0038] S4. Extrusion molding and granule preparation.

[0039] Specifically, the extruded strip is rapidly cooled and solidified by water or air cooling to obtain a stable solid strip material. Then, the cooled material is cut and granulated using a pelletizing device to form a uniform particle structure.

[0040] By controlling the matching relationship between pelletizing speed and extrusion speed, granules with stable dimensions and regular shape can be obtained, thereby meeting the requirements of subsequent injection molding or extrusion molding processes.

[0041] S5. Drying process and obtaining the finished product.

[0042] Specifically, the granules are placed in a drying device for constant-temperature drying, allowing the internal moisture to gradually evaporate, thus preventing air bubbles or material degradation during subsequent processing. After drying, the finished product, a natural antioxidant-rich cellulose diacetate granule, is obtained. The resulting granules possess natural antioxidant properties while maintaining good processing flowability and material stability, making them suitable for use in the manufacturing of eyeglass frame materials, packaging materials, and related plastic products.

[0043] Based on the above formulation and preparation process, the raw materials are expressed as a percentage by weight. The following specific examples are given using different types of raw materials, and a set of comparative examples are provided as a reference for the performance testing of the granules.

[0044] Example 1: By weight percentage, 0.4% rosemary extract was added to 30% diethyl phthalate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, it was added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours. Finally, it was extruded and granulated using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. The mixture was then dried to obtain natural antioxidant composite cellulose diacetate granules.

[0045] Example 2: By weight percentage, 0.2% fat-soluble rosemary extract and 0.2% tea polyphenol extract were added to 30% diethyl phthalate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, they were added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours. Finally, it was extruded and granulated using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. The mixture was then dried to obtain natural antioxidant composite cellulose diacetate granules.

[0046] Example 3: By weight percentage, 0.1% fat-soluble rosemary extract, 0.2% vitamin E, and 0.1% L-ascorbyl palmitate were added to 30% diethyl phthalate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, the mixture was added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours. Finally, the mixture was extruded and granulated using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. The mixture was then dried to obtain natural antioxidant composite cellulose diacetate granules.

[0047] Example 4: By weight percentage, 0.15% vitamin E, 0.07% L-ascorbyl palmitate, 0.09% tea polyphenols, and 0.09% fat-soluble rosemary extract were added to 30% diethyl phthalate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, the mixture was added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours. Finally, the mixture was extruded and granulated using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. The mixture was then dried to obtain natural antioxidant composite cellulose diacetate granules.

[0048] Example 5: By weight percentage, 0.15% vitamin E, 0.07% L-ascorbyl palmitate, 0.09% astaxanthin, and 0.09% fat-soluble rosemary extract were added to 30% diethyl phthalate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, the mixture was added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours. Finally, the mixture was extruded and granulated using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. The mixture was then dried to obtain natural antioxidant composite cellulose diacetate granules.

[0049] Example 6: By weight percentage, 0.15% vitamin E, 0.07% L-ascorbyl palmitate, 0.09% astaxanthin, and 0.09% fat-soluble rosemary extract were added to a mixture of 10% diacetate and 20% triethyl acetyl citrate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, the mixture was added to 69.8% cellulose diacetate and mixed for 40 minutes. The mixture was then matured at room temperature for 12 hours and granulated by extrusion using a twin-screw extruder. The temperatures from the feed inlet to the die were set to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃, respectively, with the die temperature set at 230℃. Finally, the mixture was dried to obtain natural antioxidant composite cellulose diacetate granules.

[0050] Comparative Example 1: By weight percentage, 0.15% vitamin E, 0.07% L-ascorbic acid palmitate, 0.09% astaxanthin, and 0.09% fat-soluble rosemary extract were added to 30% diacetate and mixed for 30 minutes until completely dissolved or evenly dispersed. Then, this mixture was added to 69.8% diacetate and mixed for 40 minutes. The raw materials were found to clump together, exhibiting high hardness and being difficult to disperse. After 12 hours of curing, the mixture could not be fed into the hopper and could not be extruded for granulation.

[0051] Based on Examples 1-6, the performance parameters of natural antioxidant composite cellulose diacetate granules are shown in Table 1.

[0052] Table 1. Performance parameters of cellulose diacetate granules with different natural antioxidants The performance indicators mentioned in Table 1 were determined using the following methods: 1. Yellowness: Load the colloidal sample into the test dish, keeping the sample loading height consistent with the height of the test dish. Repeat the test three times using a colorimeter and take the average value of the yellowness index.

[0053] 2. Secondary processing yellowness: The granule sample is extruded again through a twin-screw extruder to obtain secondary processed granules, which are then loaded into a test dish. The sample loading height is kept consistent with the height of the test dish. The yellowness index is measured three times using a colorimeter and the average value is taken.

[0054] 3. Melt index: The granule sample, after being baked in an oven at 80℃ for 8 hours, was tested three times using a melt indexer under a load of 2.16kg at 190℃, and the average weight of the outflowing sample was taken.

[0055] 4. Elongation at break: Tested according to GB / T 1040-2018 tensile test standard, with a tensile rate of 50 mm / min.

[0056] 5. Impact strength: Tested according to GB / T 1843-2008 standard for cantilever beam impact strength.

[0057] Based on the performance test items (yellowness, secondary processing yellowness, melt index, elongation at break, and impact strength) obtained from Table 1, the experimental results of Examples 1-6 and Comparative Example 1 are summarized as follows: In Examples 1-6, by introducing different types and compound forms of natural antioxidants into the cellulose diacetate system and combining them with an appropriate plasticizer system for extrusion granulation, structurally stable and uniformly dispersed natural antioxidant composite cellulose diacetate granules were successfully prepared. The test results show that the granules obtained in each example exhibited low yellowing and good secondary processing stability, indicating that the natural antioxidants in the material system can effectively inhibit oxidative degradation reactions during thermal processing, thereby reducing the material's tendency to yellow over time. Furthermore, in the melt flow index test, the granules in each example maintained stable flow properties, indicating that the introduction of natural antioxidants does not significantly affect the material's processing flowability and can meet the requirements of conventional extrusion and injection molding.

[0058] In terms of mechanical properties, the materials obtained in Examples 1-6 all exhibited good elongation at break and impact strength, indicating that the natural antioxidants and plasticizing system can form a stable and uniform composite structure in the cellulose diacetate matrix. This not only does not weaken the toughness of the material, but also maintains or improves its impact resistance to a certain extent. Among them, the examples using a combination of multiple natural antioxidants (such as Examples 3-6) showed more stable antioxidant effects and better overall performance, indicating that there is a certain synergistic antioxidant effect among different natural antioxidants, which can further improve the thermal stability and processing stability of the material.

[0059] In particular, in Example 6, by using an environmentally friendly non-phthalic plasticizer system (a combination of diacetyl glycerol and triethyl acetyl citrate), material properties comparable to those of traditional phthalate systems can be obtained. This indicates that the material system not only ensures antioxidant and processing performance but also has better environmental and safety characteristics, thus providing a feasible technical basis for the application of the material in the fields of food packaging, medical and environmental protection materials.

[0060] In contrast, Comparative Example 1, which used only diacetyl ester as a single plasticizer system, exhibited significant raw material agglomeration and clumping after the addition of natural antioxidants. Uniform dispersion was difficult to achieve during the mixing stage, and even after curing, the material could not be successfully extruded for granulation, resulting in the inability to produce stable granules. This indicates that the single plasticizer system lacks sufficient ability to dissolve or disperse natural antioxidants, making it difficult to form a stable composite system and thus severely affecting the material's processing performance.

[0061] In summary, by rationally selecting and compounding natural antioxidants in the cellulose diacetate system, and simultaneously combining them with an appropriate plasticizer system, a natural antioxidant composite cellulose diacetate granule material with good processing performance, excellent antioxidant stability, and good mechanical properties can be obtained. Compared with the comparative example, the embodiments of the present invention not only stably complete the extrusion granulation process, but also exhibit good comprehensive performance in terms of thermal stability, processing stability, and mechanical properties, verifying the feasibility and effectiveness of the technical solution of the present invention.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A natural antioxidant compound cellulose diacetate granule, characterized in that, Includes cellulose diacetate, plasticizers, and natural antioxidants; By weight: Cellulose diacetate content was 59.5–79.9 parts. The amount of plasticizer is 20-40 parts; The amount of natural antioxidant is 0.1 to 0.5 parts; The plasticizer is a phthalate plasticizer or an environmentally friendly non-phthalate plasticizer.

2. The natural antioxidant composite cellulose diacetate granules according to claim 1, characterized in that, The cellulose diacetate is prepared from wood pulp or cotton pulp as raw material, and the bound acid of the cellulose diacetate is 52.0%–56.0%.

3. The natural antioxidant composite cellulose diacetate granules according to claim 1, characterized in that, When the plasticizer is a phthalic acid plasticizer, the phthalic acid plasticizer is one or more of diethyl phthalate, dioctyl phthalate, or dibutyl phthalate.

4. The natural antioxidant composite cellulose diacetate granules according to claim 1, characterized in that, When the plasticizer is an environmentally friendly non-phthalate plasticizer, the environmentally friendly non-phthalate plasticizer is one or more of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, cyclohexane-1,2-dicarboxylic acid diisononyl ester, glycerol ester or citrate derivative.

5. The natural antioxidant composite cellulose diacetate granules according to claim 1, characterized in that, The natural antioxidant is one or more of the following: fat-soluble rosemary extract, fat-soluble tea polyphenols, vitamin E, L-ascorbyl palmitate, sesaminol, sesamolin, astaxanthin, and quercetin.

6. A method for preparing natural antioxidant composite cellulose diacetate granules, comprising preparation based on the natural antioxidant composite cellulose diacetate granules according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Construct a natural antioxidant plasticizing system; S2. Add cellulose diacetate and mix evenly for maturation; S3. Melt plasticizing treatment based on extrusion equipment; S4. Extrusion molding and granule preparation; S5. Drying process and obtaining the finished product.

7. The method for preparing a natural antioxidant composite cellulose diacetate granules according to claim 6, characterized in that, In step S1, natural antioxidants are added to plasticizers and mechanically stirred for 30 minutes at room temperature to fully dissolve or uniformly disperse the natural antioxidants in the plasticizers, forming a natural antioxidant plasticizing system.

8. The method for preparing a natural antioxidant composite cellulose diacetate granules according to claim 6, characterized in that, In step S2, the natural antioxidant plasticizer system is added to cellulose diacetate and mixed evenly for 40 minutes. After mixing, the resulting mixture is aged at room temperature for 12 to 36 hours.

9. The method for preparing a natural antioxidant composite cellulose diacetate granules according to claim 6, characterized in that, In step S3, a twin-screw extruder is used for processing, and gradient temperature control is implemented in each temperature zone of the extruder. The temperature zones from the feed inlet to the die head are set sequentially to 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃ and 230℃, with the die head temperature controlled at 230℃.

10. The method for preparing a natural antioxidant composite cellulose diacetate granules according to claim 6, characterized in that, In step S4, the extruded strip is rapidly cooled and solidified by water or air cooling to obtain a stable solid strip material. Then, the cooled material is cut and granulated by a pelletizing device to form a uniform particle structure.

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