A heat-resistant, migration-resistant, wet-sticky starch-based material, and a preparation method and application thereof

Abstract

This invention provides a heat-resistant, migration-resistant, and moisture-adhesive starch-based material. By weight, the starch-based material comprises the following components: 60-85 parts natural starch, 3-8 parts composite crosslinking agent, 5-12 parts heat-resistant modified filler, 8-15 parts low-migration composite plasticizer, 2-6 parts moisture-adhesive functional regulator, 0.5-2 parts coupling agent, 0.3-1.5 parts antioxidant stabilizer, and 30-60 parts deionized water. This invention also provides a preparation method and application of the starch-based material. Through oxidative crosslinking composite modification, functional additive compounding, and three-dimensional network structure reconstruction technology, this invention constructs a dense and stable crosslinked network, effectively inhibiting the migration and precipitation of small molecule additives, significantly improving the material's high-temperature thermal stability and resistance to moisture-heat aging, while simultaneously endowing the material with durable and controllable moisture adhesion properties. The preparation process of this invention is simple, the raw materials are inexpensive and readily available, and the material is green and biodegradable. The resulting material can be widely used in food packaging, composite adhesives, medical bonding materials, daily-use moisture-adhesive products, and biodegradable coatings.

Description

Technical Field

[0001] This invention belongs to the field of modified starch polymer materials, and in particular relates to a heat-resistant, migration-resistant, and moisture-resistant starch-based material, its preparation method, and its application. Background Technology

[0002] Starch is one of the most abundant natural polymer materials in the world, possessing outstanding advantages such as complete biodegradability, wide availability, low cost, and non-toxicity, making it widely used in packaging materials, adhesives, biomedicine, and daily chemical industries. In recent years, with the deepening of global plastic restriction policies and the continuous upgrading of consumer demand for green materials, starch-based functional materials, as an important alternative to traditional petroleum-based plastics, have seen accelerated research and industrialization.

[0003] However, conventional starch-based materials still suffer from several insurmountable technical defects in practical applications. First, they exhibit poor heat resistance. Starch molecules contain numerous hydroxyl groups, which form strong hydrogen bonds between and within molecules. This makes starch prone to thermal decomposition and structural collapse at high temperatures, resulting in generally low decomposition temperatures. This makes them unsuitable for high-temperature processing (such as hot pressing and extrusion granulation) and humid environments (such as high-temperature sterilization and hot filling). Second, additive migration is a significant problem. To overcome the hardness and brittleness of natural starch, small-molecule plasticizers such as glycerol and ethylene glycol are typically added during production. However, these small-molecule additives have weak bonding with the starch matrix and easily migrate to the material surface over time, causing stickiness, whitening, and decreased mechanical properties. They can also contaminate food or substrates in contact with the material. Third, they suffer from insufficient wet stability. Starch molecules contain numerous hydrophilic hydroxyl groups, making them highly susceptible to water absorption and swelling in high-humidity or wet environments. This disrupts the material's structural integrity, rapidly reduces adhesion, and fails to meet the wet tack retention requirements of packaging and adhesive applications. Fourth, the material has a loose structure and weak aging and weather resistance, which greatly limits the industrial promotion and multi-scenario application of starch-based materials.

[0004] Existing modified starch technologies mostly focus on single water resistance modification or strength enhancement, such as improving the hydrophobicity of starch through esterification, etherification or graft copolymerization. However, these methods often fail to simultaneously achieve the three core properties of heat resistance, migration prevention and wet adhesion. Summary of the Invention

[0005] To address the problems existing in the prior art, the first objective of this invention is to provide a heat-resistant, migration-resistant, and moisture-resistant starch-based material; the second objective of this invention is to provide a method for preparing the aforementioned heat-resistant, migration-resistant, and moisture-resistant starch-based material; and the third objective of this invention is to provide applications of the aforementioned heat-resistant, migration-resistant, and moisture-resistant starch-based material.

[0006] To achieve the first objective of this invention, the following technical solution is adopted: A heat-resistant, migration-resistant, and moisture-resistant starch-based material, comprising the following components by weight: Natural starch 60-85 parts; composite crosslinking agent 3-8 parts; heat-resistant modified filler 5-12 parts; low-migration composite plasticizer 8-15 parts; wet viscosity regulator 2-6 parts; coupling agent 0.5-2 parts; antioxidant stabilizer 0.3-1.5 parts; deionized water 30-60 parts.

[0007] Preferably, the natural starch is one or more of corn starch, tapioca starch, potato starch, and wheat starch; these starches are widely available, inexpensive, and have good biodegradability.

[0008] The composite crosslinking agent is a combination of two or more of sodium tripolyphosphate, citric acid, epichlorohydrin, and metaphosphate. The main function of the crosslinking agent is to esterify starch, that is, to react chemically with the hydroxyl groups in starch molecules, introduce new crosslinking groups, form covalent bonds between starch molecular chains, and construct a three-dimensional network structure, thereby enabling the starch material to obtain thermoplastic processing capability. At the same time, the dense crosslinking network can effectively block the migration channels of small molecule plasticizers.

[0009] Preferably, the heat-resistant modified filler is one or more of nano-montmorillonite, modified cellulose powder, silica aerogel, and basalt micro powder; these fillers have high thermal decomposition temperature and good thermal stability, and when filled in the pores of the starch cross-linked network, they can play a supporting role, enhance the structural integrity of the material in high-temperature environments, and prevent softening, melting, and thermal decomposition.

[0010] The low-migration composite plasticizer is a mixture of sorbitol, polyethylene glycol 2000, acetylated glycerol, and xylitol. The plasticizer works by penetrating between starch molecular chains, disrupting the existing strong hydrogen bond interactions, reducing internal friction between molecular chains, thereby lowering the glass transition temperature of the material and increasing the flexibility of the molecular chains.

[0011] This invention uses macromolecular polyols for compounding. Compared with traditional small-molecule plasticizers, macromolecular polyols have higher molecular weights and more hydrogen bond sites, which can form more stable bonds between starch molecules and are less prone to migration and precipitation, thus giving the material low migration characteristics.

[0012] Preferably, the wet viscosity regulator is one of modified pectin, waterborne polyurethane prepolymer, sodium alginate, or hydroxypropyl guar gum. The main function of the wet viscosity regulator is to prevent excessive reaction between starch materials and moisture, ensuring that starch products do not exhibit stickiness or other undesirable phenomena after absorbing a suitable amount of moisture in a high-humidity environment. The regulator is grafted onto the starch cross-linking network through chemical bonding, forming a stable wet viscosity control layer on the material surface, which can adjust the adhesion properties of the material surface according to the ambient humidity.

[0013] Preferably, the coupling agent is a silane coupling agent KH-550 or KH-560. The coupling agent plays a dual role in interfacial compatibilization and structural reinforcement. On the one hand, the coupling agent can improve the interfacial bonding force between the starch matrix and the heat-resistant modified filler, enabling the filler and starch to form a strong chemical bond, thereby improving the overall mechanical properties of the composite material. On the other hand, the coupling agent can also enhance the density of the starch cross-linking network, further improving the heat resistance and anti-migration properties of the material.

[0014] Preferably, the antioxidant stabilizer is a compound antioxidant prepared by vitamin E and citric acid in a weight ratio of 1:1.

[0015] In this invention, vitamin E, as the primary antioxidant, captures free radicals, terminates chain reactions, and prevents material degradation due to thermal oxidation during processing and use. Citric acid, as an auxiliary antioxidant, chelates metal ions, inhibiting their catalytic effect on oxidation reactions. When used in a 1:1 ratio, they produce a significant synergistic effect: on the one hand, the phenolic hydroxyl groups of vitamin E preferentially react with free radicals, protecting starch molecular chains from oxidative breakage; on the other hand, the carboxyl groups of citric acid form stable complexes with any trace metal ions present, reducing the catalytic effect of metal ions on oxidation reactions. This ratio was determined through extensive experimental screening. When the ratio of vitamin E to citric acid is 1:1, the composite antioxidant exhibits the highest antioxidant efficiency, effectively preventing discoloration and off-odors caused by thermal oxidation, while ensuring the material's performance stability during long-term use. Ratios that are too high or too low will reduce the synergistic effect, failing to fully leverage the complementary advantages of both.

[0016] To achieve the second objective of this invention, the following technical solution is adopted: A method for preparing the heat-resistant, migration-resistant, and moisture-adhesive starch-based material includes the following steps: S1: Starch pretreatment: Take natural starch according to the ratio, add deionized water to prepare a starch suspension with a mass fraction of 55-70%, place it in a stirred reactor, heat to 45-55℃, stir at low speed for 15-25 minutes to fully disperse and remove agglomerated particles. S2: Oxidative crosslinking modification: Slowly add the composite crosslinking agent and coupling agent to the starch suspension, adjust the pH of the system to 5.0-7.5, and react at a constant temperature for 40-60 min. Construct a three-dimensional network structure of starch molecules through hydroxyl crosslinking reaction to obtain crosslinked modified starch solution; S3: Composite ingredient modification: Add low migration composite plasticizer, heat-resistant modified filler and antioxidant stabilizer to the modified starch solution in sequence, and stir at high speed for 20 to 30 minutes with a stirring speed of 800 to 1200 r / min to make the filler and additives evenly dispersed; S4: Wet viscosity function regulation: Heat to 60-70℃, add wet viscosity function regulator, keep warm and stir for 30-45 minutes to achieve bonding and grafting of wet viscosity component with starch cross-linking network; S5: Concentration and molding post-processing: The mixture is concentrated under reduced pressure to a solid content of 45-60%, cooled, filtered, and degassed. It is then processed by casting, extrusion granulation, or coating molding. It is then air-dried at room temperature or dried at low temperature to obtain a heat-resistant, migration-resistant, and moisture-resistant starch-based material.

[0017] Preferably, the crosslinking reaction in step S2 adopts a segmented temperature control mode, with the initial reaction at a constant temperature of 45°C for 20 minutes, and the subsequent reaction slowly increased to 55°C for 30 minutes.

[0018] The above-mentioned segmented temperature control method can make the cross-linking reaction more uniform and complete. The low temperature reaction in the early stage is conducive to the uniform diffusion and initial reaction of the cross-linking agent, while the temperature rise in the later stage can accelerate the cross-linking reaction process, thereby forming a denser three-dimensional network structure.

[0019] Preferably, the low-temperature drying temperature in step S5 is controlled at 40-50℃.

[0020] The aforementioned low-temperature drying temperature range can effectively remove residual moisture from the material without causing the wet tack modifier to become inactive or decompose due to high temperature, thus ensuring the long-term stability of the material's wet tack performance.

[0021] To achieve the third objective of this invention, the following technical solution is adopted: The application of the heat-resistant, migration-resistant, and moisture-adhesive starch-based material described above in the preparation of high-moisture food sealing packaging, environmentally friendly water-based moisture-adhesive adhesives, medical breathable bonding substrates, daily chemical moisture-adhesive patches, biodegradable waterproof coatings, or paper composite moisture-adhesive materials.

[0022] In the field of high-humidity packaging, this starch-based material can be used as a moisture-proof bonding coating for fresh fruits and vegetables, effectively blocking moisture penetration while maintaining appropriate wet tack, ensuring a strong bond between the packaging material and the product. In the adhesive field, this material can replace traditional chemical adhesives for wet bonding of paper, non-woven fabrics, and plant fibers, offering environmental advantages such as being formaldehyde-free, solvent-free, and biodegradable. In the medical field, this material can be used to prepare low-irritation, sweat-resistant medical fixation patch substrates, adapting to the humid and hot environment of human skin, providing long-lasting adhesion strength without irritating the skin. In the daily chemical and industrial coating fields, this material can be used to prepare wet-adhesive daily chemical patches and biodegradable waterproof wet-adhesive coatings, suitable for use in high-humidity conditions.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention constructs a dense and stable three-dimensional network structure of starch molecules through synergistic techniques of composite crosslinking modification, low-migration additive compounding, heat-resistant filler reinforcement, and wet adhesion functional grafting modification. This three-dimensional network structure of starch molecules effectively inhibits the migration and precipitation of small molecule additives, significantly improving the high-temperature thermal stability and resistance to damp heat aging of the material. At the same time, through the chemical bonding grafting of wet adhesion functional regulators, the material is endowed with durable and controllable wet adhesion properties, and its overall performance is superior to that of existing technologies. The composite antioxidant of vitamin E and citric acid in a 1:1 ratio can produce a significant synergistic effect, effectively preventing thermal oxidative degradation of the material during processing and use, and avoiding discoloration and odor.

[0024] (2) The preparation method of the present invention adopts a five-step synergistic process, with mild reaction conditions, no need for high temperature and high pressure, no use of toxic reagents, low energy consumption, and can be adapted to various molding processes such as casting, extrusion, coating, and granulation, making it suitable for industrial mass production.

[0025] (3) The material formulation of the present invention is adjustable, and the hardness, viscosity and heat resistance grade can be flexibly adjusted according to different application scenarios. It has strong versatility. The heat-resistant and anti-migration wet adhesive starch-based material of the present invention can be widely used in high-humidity food sealing packaging, environmentally friendly water-based wet adhesives, medical breathable bonding substrates, daily chemical wet adhesive patches, biodegradable waterproof coatings and paper composite wet adhesive materials, etc. It has high industrialization promotion value and broad market application prospects. Detailed Implementation

[0026] The invention can be further understood through the specific embodiments given below, but they are not intended to limit the invention. Example 1

[0027] This embodiment 1 provides a heat-resistant, migration-resistant, and moisture-adhesive starch-based material, which, by weight, comprises the following components: 75 parts cassava starch, 5 parts citric acid and sodium tripolyphosphate composite crosslinking agent, 8 parts nano montmorillonite, 12 parts sorbitol and polyethylene glycol 2000 composite plasticizer, 3 parts waterborne polyurethane prepolymer wet viscosity regulator, 1 part silane coupling agent KH-550, 0.25 parts vitamin E, 0.25 parts citric acid composite antioxidant, and 45 parts deionized water.

[0028] The preparation method of the heat-resistant, migration-resistant, and moisture-adhesive starch-based material in Example 1 includes the following steps: S1: Starch pretreatment: Add cassava starch to deionized water to prepare a starch suspension with a mass fraction of about 60%. Place the suspension in a stirred reactor, heat to 50°C, and stir at low speed for 20 minutes to fully disperse the starch and remove agglomerated particles.

[0029] S2: Oxidative crosslinking modification: Citric acid and sodium tripolyphosphate composite crosslinking agent and silane coupling agent KH-550 are slowly added to starch suspension. The pH of the system is adjusted to 6.0. The crosslinking reaction is carried out in a segmented temperature control mode. The initial reaction is carried out at a constant temperature of 45℃ for 20 min. The temperature is then slowly increased to 55℃ and the reaction is continued for 30 min. A three-dimensional network structure of starch molecules is constructed through hydroxyl crosslinking reaction to obtain crosslinked modified starch solution.

[0030] S3: Composite ingredient modification: Add sorbitol and polyethylene glycol 2000 composite plasticizer, nano montmorillonite and vitamin E and citric acid composite antioxidant to the modified starch solution in sequence, and shear and stir at 1000 r / min for 25 min to make the filler and additives evenly dispersed.

[0031] S4: Wet viscosity control: Heat the system to 65℃, add waterborne polyurethane prepolymer wet viscosity regulator, keep warm and stir for 40 minutes to achieve bonding grafting of wet viscosity component and starch crosslinking network.

[0032] S5: Post-concentration molding treatment: The mixture is concentrated under reduced pressure to a solid content of 52%, cooled, filtered, and degassed. The mixture is then dried at a low temperature of 45°C using a casting process to finally obtain a starch-based film material, which is labeled as sample Y1. Example 2

[0033] This embodiment 2 provides a heat-resistant, migration-resistant, and moisture-adhesive starch-based material, which, by weight, comprises the following components: 68 parts corn starch, 6 parts metaphosphate and epichlorohydrin composite crosslinking agent, 10 parts modified cellulose powder, 10 parts acetylated glycerol and xylitol composite plasticizer, 4 parts sodium alginate wet viscosity regulator, 1.2 parts silane coupling agent KH-560, 0.8 parts vitamin E and citric acid composite antioxidant (weight ratio 1:1), and 50 parts deionized water.

[0034] The preparation method of the heat-resistant, migration-resistant, and moisture-adhesive starch-based material in Example 2 is basically the same as that in Example 1, with the only difference being the adjustment of the formulation and some process parameters. Specifically: In step S1, corn starch is used. After the suspension is prepared, it is heated to 48°C and stirred at low speed for 22 minutes. In step S2, the pH of the crosslinking reaction is adjusted to 6.8, and the segmented temperature control mode is still used (45℃ / 20min in the early stage, 55℃ / 30min in the later stage); in step S3, the high-speed shear stirring speed is 900r / min, and the stirring time is 30min. In step S4, the wet viscosity control temperature is 62℃, and the holding and stirring time is 35min; In step S5, the solids content was concentrated to 55%, and starch-based granular material was obtained by extrusion granulation process and labeled as sample Y2.

[0035] Comparative Example This comparative example uses ordinary unmodified cassava starch as the control sample. Following the conventional gelatinization process, cassava starch is mixed with deionized water, and conventional glycerol is added as a plasticizer (the amount is equivalent to the total weight of the composite plasticizer in Example 1). After gelatinization, the mixture is cast into a film without the addition of crosslinking agents, heat-resistant modified fillers, wet viscosity modifiers, or coupling agents. The antioxidant stabilizer is the same as in Example 1. This comparative sample is marked as sample D1.

[0036] Performance testing The performance of sample Y1 prepared in Example 1, sample Y2 prepared in Example 2, and comparative sample D1 were tested respectively. The test items and methods are as follows: ① Heat distortion temperature: According to GB / T 1634.2-2019 standard, using method B (load 0.45MPa), with the specimen laid flat, the heating rate is 120℃ / h, the temperature at which the material undergoes the specified deformation is tested.

[0037] ② 7d Additive Migration and Precipitation Rate: The sample was placed at a constant temperature of 70℃ for 7 days, and the mass change of the sample before and after placement was measured. The additive migration and precipitation rate was calculated and expressed as a percentage of mass loss.

[0038] ③Wet bond strength: According to GB / T 2791-1995 standard, the sample is coated on the standard test substrate and placed in an environment with a relative humidity of 90% for 24 hours. The peel strength is then tested using a universal tensile testing machine.

[0039] ④ Stability of resistance to damp heat aging: Place the sample in a constant temperature and humidity chamber at 60℃ and 90% relative humidity for 72 hours. After taking it out, observe the surface condition of the sample and record whether cracking, debonding, softening or other phenomena occur.

[0040] The detailed results of the above tests are shown in Table 1.

[0041]

[0042] The results in Table 1 show that: Regarding heat distortion temperature: Sample Y1 from Example 1 had a heat distortion temperature of 123℃, sample Y2 from Example 2 had a heat distortion temperature of 118℃, while the comparative sample D1 only had a heat distortion temperature of 75℃. The heat distortion temperatures of both sets of sample examples exceeded 115℃, an improvement of approximately 57% compared to the comparative sample. This result fully demonstrates that the present invention significantly improves the high-temperature structural stability of the material by constructing a three-dimensional network structure of starch molecules through a composite crosslinking agent, combined with the reinforcing effect of heat-resistant modified fillers. The crosslinking reaction introduces covalent bonds between starch molecular chains, restricting the movement of molecular chains at high temperatures; heat-resistant fillers such as nano-montmorillonite and modified cellulose powder have high thermal decomposition temperatures, providing skeletal support and preventing the material from softening and collapsing at high temperatures. In contrast, the comparative sample, lacking crosslinking modification, had starch molecules bound only by hydrogen bonds, which were broken at high temperatures, leading to rapid softening of the material. The significant increase in heat distortion temperature enables the material of the present invention to adapt to high-temperature processing and humid heat applications, such as hot-fill packaging and high-temperature sterilization.

[0043] Regarding the 7-day migration and precipitation rate of additives: the 7-day migration and precipitation rate of additives in sample Y1 of Example 1 was 0.21%, that of sample Y2 of Example 2 was 0.28%, while that of the comparative sample D1 was as high as 8.65%. The migration and precipitation rates of additives in the two sets of examples were much lower than those in the comparative example, with a reduction of more than 96%. This result indicates that the dense three-dimensional network constructed by the composite cross-linking technology used in this invention can effectively block the migration channels of small molecule additives. Meanwhile, the low-migration composite plasticizer uses macromolecular polyols such as sorbitol, polyethylene glycol 2000, acetylated glycerol, and xylitol. These macromolecules have more hydrogen bond binding sites, enabling them to form a more stable bond with starch molecules, making them less prone to free migration. The conventional glycerol used in the comparative example is a small molecule plasticizer with low molecular weight and weak binding force, which easily diffuses from the starch matrix to the surface, resulting in a high migration and precipitation rate. Low migration rate means that the material can maintain stable surface and mechanical properties during use, without problems such as stickiness or whitening due to plasticizer precipitation, and without contaminating the food or substrate it comes into contact with.

[0044] Regarding wet adhesion strength: Sample Y1 from Example 1 had a wet adhesion strength of 0.45 MPa, Sample Y2 from Example 2 had a wet adhesion strength of 0.52 MPa, while the comparative sample D1 only had a wet adhesion strength of 0.12 MPa. The wet adhesion strength of the two sets of examples was 3-4 times higher than that of the comparative example. This result shows that the present invention successfully endows the material with stable adhesion properties in a humid environment through chemical bonding grafting of wet adhesion functional modifiers. The wet adhesion functional modifiers (waterborne polyurethane prepolymer, sodium alginate, etc.) combine with the starch crosslinking network through chemical reaction to form a stable wet adhesion regulating layer on the material surface. This regulating layer can maintain a moderate adhesion force in a high humidity environment without losing its adhesion ability due to water absorption and swelling. The comparative sample, due to the lack of wet adhesion functional regulation, experienced a large amount of water absorption and swelling of starch molecules in a high humidity environment, which destroyed the structural integrity of the material and led to a sharp decrease in adhesion force. The high wet adhesion strength makes the material of the present invention particularly suitable for applications requiring stable wet adhesion, such as packaging and medical bonding in high humidity environments.

[0045] Regarding the stability against damp heat aging: After a 72-hour damp heat aging test (60℃, 90% relative humidity), the surfaces of the samples from Examples 1 and 2 remained intact, without cracking or delamination; while the comparative sample showed significant softening and severe delamination. This result indicates that the synergistic effect of the cross-linked network structure and the heat-resistant filler of this invention significantly improves the material's resistance to damp heat aging. The cross-linked network restricts the movement of starch molecular chains, reducing the diffusion rate of water molecules; the heat-resistant filler enhances the overall rigidity of the material; and the surface layer formed by the wet adhesion regulator acts as a barrier against moisture. The synergistic effect of these three factors enables the material to maintain structural stability and reliable performance in damp heat environments. This characteristic is crucial for the long-term use of the material in high-humidity packaging, medical bonding, and other fields.

[0046] In summary, the heat-resistant, migration-resistant, and wet-adhesion-resistant starch-based material, its preparation method, and its applications provided by this invention, through synergistic technologies of composite crosslinking modification, low-migration additive compounding, heat-resistant filler reinforcement, and wet-adhesion functional grafting modification, significantly outperforms existing products in several key indicators, including heat distortion temperature, additive migration inhibition, wet bond strength, and resistance to damp heat aging. This invention features a simple preparation process, inexpensive and readily available raw materials, and is environmentally friendly and biodegradable. It can be widely applied in food packaging, environmentally friendly adhesives, medical materials, and daily and industrial coatings, possessing extremely high industrialization value and broad market application prospects.

[0047] The above description is merely an embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A heat-resistant, migration-resistant, and moisture-adhesive starch-based material, characterized in that, By weight, it includes the following components: Natural starch 60-85 parts; composite crosslinking agent 3-8 parts; heat-resistant modified filler 5-12 parts; low-migration composite plasticizer 8-15 parts; wet viscosity regulator 2-6 parts; coupling agent 0.5-2 parts; antioxidant stabilizer 0.3-1.5 parts; deionized water 30-60 parts.

2. The heat-resistant, migration-resistant, and moisture-adhesive starch-based material according to claim 1, characterized in that, The natural starch is one or more of corn starch, tapioca starch, potato starch, and wheat starch; the composite crosslinking agent is a combination of two or more of sodium tripolyphosphate, citric acid, epichlorohydrin, and metaphosphate.

3. The heat-resistant, migration-resistant, and moisture-adhesive starch-based material according to claim 1, characterized in that, The heat-resistant modified filler is one or more of nano-montmorillonite, modified cellulose powder, silica aerogel, and basalt micro powder; the low-migration composite plasticizer is a composite mixture of sorbitol, polyethylene glycol 2000, acetylated glycerol, and xylitol.

4. The heat-resistant, migration-resistant, and moisture-adhesive starch-based material according to claim 1, characterized in that, The wet viscosity modifier is one of modified pectin, waterborne polyurethane prepolymer, sodium alginate, or hydroxypropyl guar gum.

5. The heat-resistant, migration-resistant, and moisture-adhesive starch-based material according to claim 1, characterized in that, The coupling agent is a silane coupling agent KH-550 or KH-560.

6. The heat-resistant, migration-resistant, and moisture-adhesive starch-based material according to claim 1, characterized in that, The antioxidant stabilizer is a compound antioxidant formulated with vitamin E and citric acid in a weight ratio of 1:

1.

7. A method for preparing a heat-resistant, migration-resistant, and moisture-adhesive starch-based material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Starch pretreatment: Take natural starch according to the ratio, add deionized water to prepare a starch suspension with a mass fraction of 55-70%, place it in a stirred reactor, heat to 45-55℃, stir at low speed for 15-25 minutes to fully disperse and remove agglomerated particles. S2: Oxidative crosslinking modification: Slowly add the composite crosslinking agent and coupling agent to the starch suspension, adjust the pH of the system to 5.0-7.5, and react at a constant temperature for 40-60 min. Construct a three-dimensional network structure of starch molecules through hydroxyl crosslinking reaction to obtain crosslinked modified starch solution; S3: Composite ingredient modification: Add low migration composite plasticizer, heat-resistant modified filler and antioxidant stabilizer to the modified starch solution in sequence, and stir at high speed for 20 to 30 minutes with a stirring speed of 800 to 1200 r / min to make the filler and additives evenly dispersed; S4: Wet viscosity function regulation: Heat to 60-70℃, add wet viscosity function regulator, keep warm and stir for 30-45 minutes to achieve bonding and grafting of wet viscosity component with starch cross-linking network; S5: Concentration and molding post-processing: The mixture is concentrated under reduced pressure to a solid content of 45-60%, cooled, filtered, and degassed. It is then processed by casting, extrusion granulation, or coating molding. It is then air-dried at room temperature or dried at low temperature to obtain a heat-resistant, migration-resistant, and moisture-resistant starch-based material.

8. The preparation method according to claim 7, characterized in that, In step S2, the crosslinking reaction adopts a segmented temperature control mode. In the early stage, the reaction is carried out at a constant temperature of 45°C for 20 minutes, and in the later stage, the temperature is slowly increased to 55°C and the reaction continues for 30 minutes.

9. The preparation method according to claim 7, characterized in that, In step S5, the low-temperature drying temperature is controlled at 40-50℃.

10. The application of a heat-resistant, migration-resistant, and moisture-adhesive starch-based material as described in any one of claims 1 to 6 in the preparation of high-moisture food sealing packaging, environmentally friendly water-based moisture-adhesive adhesives, medical breathable bonding substrates, daily chemical moisture-adhesive patches, biodegradable waterproof coatings, or paper composite moisture-adhesive materials.

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