High-toughness composite resin film, and preparation method and application thereof

Abstract

This invention relates to the field of composite material preparation technology, and more particularly to a high-toughness composite resin film, its preparation method, and its applications. The high-toughness composite resin film provided by this invention utilizes the synergistic effect between nanoparticles and graphene nanosheets, as well as the compatibility differences between nanoparticles and resin, to construct a basic toughness system. Furthermore, this invention utilizes the coating and physical entanglement structure between graphene nanosheets and resin to further improve the toughness and tensile strength of the system. This invention also utilizes the loading and dispersing effect of graphene nanosheets on nanoparticles to ensure the uniformity of the system, thereby significantly improving the puncture strength of the high-toughness composite resin film. In summary, through the interaction of the above components, this invention achieves a significant improvement in the toughness of the resin film, endowing the high-toughness composite resin film with high toughness, high tensile strength, and high puncture strength, exhibiting excellent overall performance.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and in particular to a high-toughness composite resin film, its preparation method, and its application. Background Technology

[0002] With the development of the transportation industry, especially the rapid growth in the volume of high-value goods transported, transportation safety has become an increasingly important aspect. How to safely and effectively package transported products, especially high-value goods (such as precision instruments and electronic components), while keeping costs under control, to efficiently absorb external impacts and ensure transportation safety, is a new challenge facing the transportation industry.

[0003] For the transportation of high-value goods, packaging materials serve as a protective measure, ensuring that these goods are not subjected to vibration, collision, or compression during transport. Commonly used packaging materials include foam plastics, air cushion films, and corrugated cardboard. Among these, air cushion films are widely used due to their excellent cushioning and shock absorption properties, as well as their lightweight nature.

[0004] However, existing air cushion films also have some shortcomings, such as being only suitable for packaging lightweight items and having limited cushioning effect for heavy or bulky goods. Summary of the Invention

[0005] In view of this, the present invention provides a high-toughness composite resin film, its preparation method and application. The high-toughness composite resin film provided by the present invention has excellent toughness and can effectively improve the cushioning effect of air cushion film.

[0006] This invention provides a high-toughness composite resin film, prepared from the following raw materials in parts by weight: The composition comprises 100 parts low-density polyethylene resin (LDPE), 3-7 parts chitosan-silica nanoparticles, 8-15 parts polylactic acid-alkali nanoparticles, 6-10 parts graphene nanosheets, 0.1-0.5 parts whitening agent, 0.3-0.6 parts opening agent, 0.1-0.3 parts antioxidant, and 0.2-0.5 parts light stabilizer; wherein the chitosan-silica nanoparticles comprise silica and chitosan coated on the surface of the silica; wherein the polylactic acid-alkali nanoparticles comprise polylactic acid and alkali distributed in the polylactic acid.

[0007] Preferably, the chitosan-silica nanoparticles have a particle size of 35-62 nanometers; the mass ratio of silica to chitosan is 100:80-110.

[0008] Preferably, the preparation method of the chitosan-silica nanoparticles includes the following steps: mixing silica particles and phosphate buffer solution to obtain a dispersion, and then mixing chitosan solution, acid and the dispersion for coating; the amount of acid added is such that the pH value of the system is not higher than 6.2.

[0009] Preferably, the polylactic acid-base nanoparticles have a particle size of 6-9 nanometers; the base is sodium carbonate or calcium hydroxide; and the polylactic acid has a thickness of 3-5 nanometers.

[0010] Preferably, the preparation method of the polylactic acid-base nanoparticles includes the following steps: mixing polylactic acid, base and compatibilizer and kneading for 5 to 8 minutes, followed by granulation, cooling and crushing at a rate of 10 to 40 °C / min.

[0011] Preferably, the graphene nanosheets have a thickness of 6-8 nanometers and a lateral dimension (width) of 10-25 micrometers.

[0012] The present invention also provides a method for preparing the high-toughness composite resin film described above, comprising the following steps: (1) Low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer are mixed and kneaded (referred to as the first kneading) to obtain composite resin; (2) The composite resin and polylactic acid-base nanoparticles are mixed and kneaded (referred to as the second kneading), plasticized and calendered in sequence to obtain the high-toughness composite resin film.

[0013] Preferably, the conditions for the second mixing are: the extruder temperature zone gradient is set to 150°C, 170°C, 180°C and 175°C, the die head temperature is 160°C; the screw speed is 150~250 rpm; and the feeding speed is 8~12 rpm.

[0014] Preferably, the plasticizing temperature is 160~190 degrees Celsius, and the holding time is 40~60 minutes.

[0015] The present invention also provides the application of the high-toughness composite resin film described in the above-described scheme or the high-toughness composite resin film obtained by the preparation method described in the above-described scheme in the transportation or packaging fields.

[0016] This invention provides a high-toughness composite resin film. The high-toughness composite resin film provided by this invention utilizes the synergistic effect between nanoparticles and graphene nanosheets, as well as the compatibility differences between nanoparticles and resin, to construct a basic toughness system. This invention further utilizes the coating and physical entanglement structure between graphene nanosheets and resin to further improve the toughness and tensile strength of the system. This invention also utilizes the loading and dispersing effect of graphene nanosheets on nanoparticles to ensure the uniformity of the system, thereby significantly improving the puncture strength of the high-toughness composite resin film. In summary, through the interaction of the above components, this invention achieves a significant improvement in the toughness of the resin film, endowing the high-toughness composite resin film with high toughness, high tensile strength, and high puncture strength, exhibiting excellent overall performance.

[0017] This invention also provides a method for preparing the high-toughness composite resin film described above. The preparation method provided by this invention has simple steps, is easy to operate, has good safety, high stability, and is suitable for industrial production.

[0018] This invention also provides the application of the high-toughness composite resin film described in the above-described scheme or the high-toughness composite resin film prepared by the above-described scheme in the transportation or packaging fields. The high-toughness composite resin film provided by this invention has excellent toughness, and maintains good levels of tensile strength and puncture strength, with significantly improved overall performance and relatively low cost, making it more suitable for the transportation or packaging fields. It can play a good protective role for transported or packaged products and has broad application prospects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this invention, the accompanying drawings used in the embodiments of this invention or in the prior art are briefly described below. For those skilled in the art, other drawings can be derived from the following drawings without creative effort, and all such drawings are within the protection scope of this invention.

[0020] Figure 1 The diagram shows a comparison of the toughness of the high-toughness composite resin films in Examples 1-6 and Comparative Examples 1-3. Detailed Implementation

[0021] This invention provides a high-toughness composite resin film, prepared from the following raw materials in parts by weight: 100 parts low-density polyethylene resin (LDPE), 3-7 parts chitosan-silica nanoparticles, 8-15 parts polylactic acid-alkali nanoparticles, 6-10 parts graphene nanosheets, 0.1-0.5 parts whitening agent, 0.3-0.6 parts opening agent, 0.1-0.3 parts antioxidant, and 0.2-0.5 parts light stabilizer.

[0022] The high-toughness composite resin film provided by this invention comprises 100 parts by weight of low-density polyethylene resin; the density of the low-density polyethylene is preferably 0.91~0.93 g / cm³. 3 .

[0023] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention comprises 3 to 7 parts of chitosan-silica nanoparticles, preferably 4 to 6 parts, and more preferably 5.3 parts.

[0024] In this invention, the chitosan-silica nanoparticles preferably comprise silica and chitosan coated on the surface of the silica; the number-average molecular weight of the chitosan is preferably 7,000 to 15,000, more preferably 10,000 to 13,000; the mass ratio of silica to chitosan is preferably 100:80 to 110, more preferably 100:86 to 101, and even more preferably 100:92 to 95.

[0025] In this invention, the particle size of the chitosan-silica nanoparticles is preferably 35-62 nanometers, and more preferably 40-57 nanometers.

[0026] In this invention, the method for preparing the chitosan-silica nanoparticles preferably includes the following steps: mixing silica particles and phosphate buffer solution to obtain a dispersion, and then mixing chitosan solution, acid and the dispersion for coating.

[0027] In this invention, the pH value of the phosphate buffer solution is preferably 7.2 to 7.4.

[0028] In this invention, the content of silica particles in the dispersion is preferably 5-8 wt%, more preferably 6 wt%.

[0029] In this invention, the concentration of the chitosan solution is preferably 1-5 wt%, more preferably 2-3 wt%.

[0030] In this invention, the mass ratio of the silica particles to the chitosan in the chitosan solution is preferably 100:100~120, more preferably 100:110.

[0031] In this invention, the acid is preferably an organic acid; the organic acid is preferably acetic acid.

[0032] In this invention, the amount of acid added is preferably such that the pH value of the system is not higher than 6.2, and more preferably 5.7 to 6.2.

[0033] In this invention, the coating temperature is preferably room temperature; the coating time is preferably 3 to 8 hours, more preferably 5 to 6 hours; the coating is preferably carried out under stirring conditions; the stirring speed is preferably 80 to 150 rpm, more preferably 90 to 110 rpm.

[0034] In this invention, the coating process preferably further includes centrifuging and washing the resulting product system sequentially.

[0035] This invention utilizes a physical adsorption method based on electrostatic interaction. Under acidic conditions, chitosan is coated onto the surface of silica. The amino groups on the chitosan molecular chain are protonated and positively charged, while the hydroxyl groups on the silica surface are negatively charged. The two undergo physical adsorption through electrostatic attraction.

[0036] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention comprises 8 to 15 parts of polylactic acid-base nanoparticles, preferably 10 to 14 parts, and more preferably 12.6 parts.

[0037] In this invention, the polylactic acid-base nanoparticles preferably comprise polylactic acid and an alkali distributed in the polylactic acid; the alkali is preferably sodium carbonate or calcium hydroxide; the thickness of the polylactic acid is preferably 3-5 nanometers, more preferably 4 nanometers; the particle size of the polylactic acid-base nanoparticles is preferably 6-9 nanometers, more preferably 7-8 nanometers.

[0038] In this invention, the preparation method of the polylactic acid-base nanoparticles preferably includes the following steps: mixing polylactic acid, base and compatibilizer for compounding (referred to as the third compounding) and then granulating, cooling and crushing in sequence.

[0039] In this invention, the mass ratio of polylactic acid to alkali is preferably 10~20:3~5, and more preferably 15:4.

[0040] In this invention, the compatibilizer is preferably one or more of silane coupling agent KH-550 and silane coupling agent KH-560.

[0041] In this invention, the mass ratio of the compatibilizer to the alkali is preferably 10:1 to 3, and more preferably 10:2.

[0042] In this invention, the temperature of the third mixing is preferably 100-120 degrees Celsius, more preferably 105 degrees Celsius, and the time of the third mixing is preferably 5-8 minutes, more preferably 7 minutes.

[0043] In this invention, the cooling method is preferably air cooling or water cooling; the final cooling temperature is preferably below 45 degrees Celsius; and the cooling rate is preferably 10~40℃ / min, more preferably 30~40℃ / min.

[0044] In this invention, the crushing process preferably includes sieving the resulting product; the target particle size for sieving is preferably 6-9 nanometers, more preferably 7-8 nanometers.

[0045] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention includes 6 to 10 parts of graphene nanosheets, preferably 8 to 9 parts, and more preferably 8.6 parts.

[0046] In this invention, the thickness of the graphene nanosheets is preferably 6-8 nanometers, and the lateral dimension (width) is preferably 10-25 micrometers, more preferably 15-20 micrometers.

[0047] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention includes 0.1 to 0.5 parts of whitening agent, preferably 0.2 to 0.4 parts, and more preferably 0.3 parts.

[0048] In this invention, the whitening agent is preferably a dibenzylidene sorbitol whitening agent or an organophosphate salt whitening agent; the dibenzylidene sorbitol whitening agent is preferably Millad 3905 whitening agent; the organophosphate salt whitening agent is preferably NA-11 whitening agent.

[0049] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention includes 0.3 to 0.6 parts of an opening agent, preferably 0.4 to 0.5 parts.

[0050] In this invention, the opening agent preferably includes one or more of talc and diatomaceous earth.

[0051] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention includes 0.1 to 0.3 parts of antioxidant, preferably 0.2 parts.

[0052] In this invention, the antioxidant preferably includes hindered phenolic antioxidants and phosphite-based auxiliary antioxidants; the hindered phenolic antioxidant preferably includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 330; the phosphite-based auxiliary antioxidant is preferably antioxidant 168; the mass ratio of the hindered phenolic antioxidant to the phosphite-based auxiliary antioxidant is preferably 1~5:1~10, more preferably 3~4:4~7.

[0053] Based on the mass fraction of the low-density polyethylene resin, the high-toughness composite resin film provided by the present invention includes 0.2 to 0.5 parts of light stabilizer, preferably 0.3 to 0.4 parts.

[0054] In this invention, the light stabilizer preferably includes one or more of light stabilizer 770 and light stabilizer 622.

[0055] The present invention also provides a method for preparing the high-toughness composite resin film described above, comprising the following steps: (1) Low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer are mixed and kneaded (referred to as the first kneading) to obtain composite resin; (2) The composite resin and polylactic acid-base nanoparticles are mixed and kneaded (referred to as the second kneading), plasticized and calendered in sequence to obtain the high-toughness composite resin film.

[0056] This invention involves mixing and compounding low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, a whitening agent, an opening agent, an antioxidant, and a light stabilizer to obtain a composite resin. In this invention, the preferred temperature for the first compounding is 180-200 degrees Celsius, more preferably 185 degrees Celsius, and the preferred compounding time is 8-12 minutes, more preferably 10 minutes.

[0057] After obtaining the composite resin, the present invention mixes the composite resin and polylactic acid-base nanoparticles and sequentially performs kneading, plasticizing, and calendering to obtain the high-toughness composite resin film. In the present invention, the preferred conditions for the second kneading are: extruder temperature gradient settings of 150°C, 170°C, 180°C, and 175°C, die head temperature of 160°C; screw speed of 150~250 rpm; and feeding speed of 8~12 rpm.

[0058] In this invention, the plasticizing temperature is preferably 160-190 degrees Celsius, more preferably 170-180 degrees Celsius, and the holding time is preferably 40-60 minutes, more preferably 50 minutes.

[0059] In this invention, the rolling temperature is preferably 150-160 degrees Celsius, more preferably 155 degrees Celsius, the pressure is preferably 350-600 kPa, more preferably 400-500 kPa, and the holding time is preferably 10-20 seconds, more preferably 18-20 seconds.

[0060] This invention utilizes the high-temperature conditions of the second mixing, plasticizing, and calendering processes, and leverages the alkali in the polylactic acid-alkali nanoparticles to provide alkaline conditions for polylactic acid, gradually accelerating the hydrolysis of intramolecular ester bonds and transesterification reactions, achieving a degradation rate of over 90% for polylactic acid, forming a hollow closed microporous structure that carries the degradation products of polylactic acid, endowing the high-toughness composite resin film with good toughness, without affecting its tensile strength and puncture strength, resulting in strong comprehensive performance.

[0061] This invention introduces chitosan-silica nanoparticles into low-density polyethylene resin. By utilizing the compatibility difference between the two, the chitosan-silica nanoparticles are more easily enriched on the surface of graphene nanosheets. The two work synergistically to increase the movable and slippery structure in the high-toughness composite resin film, laying a good foundation for its high toughness.

[0062] The present invention also provides the application of the high-toughness composite resin film described in the above-described scheme or the high-toughness composite resin film obtained by the preparation method described in the above-described scheme in the transportation or packaging fields.

[0063] The high-toughness composite resin film provided by this invention has excellent toughness, and maintains good levels of tensile strength and puncture strength. Its overall performance is significantly improved, and its cost is relatively low. It is more suitable for the transportation or packaging fields, and can play a good protective role for transported or packaged products. It has broad application prospects.

[0064] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments.

[0065] Example 1: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 3 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:80; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 8 kg of polylactic acid-base nanoparticles; the base is sodium carbonate; the thickness of the polylactic acid is 3 nanometers; the particle size of the polylactic acid-base nanoparticles is 6 nanometers. Graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers) 6 kg; 0.1 kg of whitening agent (Millad 3905 whitening agent); Opening agent (talc) 0.3 kg; Antioxidant (antioxidant 1010 and antioxidant 168 in a mass ratio of 5:9) 0.1 kg; Light stabilizer (light stabilizer 770) 0.2 kg.

[0066] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (silica particle content was 8wt%). Then, chitosan solution (concentration was 5wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 6.2. The mixture was coated at room temperature for 8 hours under stirring speed of 100rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:100. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0067] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 20:5 and the mass ratio of silane coupling agent KH-550 to base of 10:3. The mixture was kneaded at 120 degrees Celsius for 5 minutes, granulated, cooled to room temperature by air at a cooling rate of 30℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0068] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 180 degrees Celsius for 12 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 200 rpm and the feeding speed was 12 rpm. Then, the material was plasticized by holding it at 160°C for 60 minutes and calendering it for 10 seconds at 150°C and 500 kPa to obtain a high-toughness composite resin film.

[0069] Example 2: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 7 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:110; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 15 kg of polylactic acid-base nanoparticles; the base is sodium carbonate; the thickness of the polylactic acid is 5 nanometers; the particle size of the polylactic acid-base nanoparticles is 9 nanometers. 10 kg of graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers); 0.5 kg of whitening agent (Millad 3905 whitening agent); Opening agent (talc) 0.6 kg; Antioxidant (antioxidant 1010 and antioxidant 168 in a 1:10 mass ratio) 0.3 kg; Light stabilizer (light stabilizer 770) 0.5 kg.

[0070] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (silica particle content was 5wt%). Then, chitosan solution (concentration was 1wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 6. The mixture was coated at room temperature for 6 hours under stirring speed of 110 rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:120. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0071] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 10:3 and the mass ratio of silane coupling agent KH-550 to base of 10:3. The mixture was kneaded at 100 degrees Celsius for 8 minutes, granulated, cooled to room temperature by air at a cooling rate of 40℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0072] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 200 degrees Celsius for 8 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 200 rpm and the feeding speed was 8 rpm. Then, the material was plasticized by holding it at 190°C for 40 minutes and calendering it at 160°C and 400 kPa for 20 seconds to obtain a high-toughness composite resin film.

[0073] Example 3: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 4 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:80; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 8 kg of polylactic acid-base nanoparticles; the base is calcium hydroxide; the thickness of the polylactic acid is 5 nanometers; the particle size of the polylactic acid-base nanoparticles is 8 nanometers. 10 kg of graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers); 0.3 kg of whitening agent (NA-11 whitening agent); Opening agent (diatomaceous earth) 0.3 kg; Antioxidant (antioxidant 1010 and antioxidant 168 in a mass ratio of 5:7) 0.2 kg; Light stabilizer (light stabilizer 622) 0.4 kg.

[0074] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (the content of silica particles was 7.3 wt%). Then, chitosan solution (concentration was 3.2 wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 6.2. The mixture was coated at room temperature for 3 hours under stirring speed of 150 rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:120. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0075] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 15:4 and the mass ratio of silane coupling agent KH-550 to base of 10:2. The mixture was kneaded at 110 degrees Celsius for 7 minutes, granulated, cooled to room temperature by air at a cooling rate of 30℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0076] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 200 degrees Celsius for 8 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 250 rpm and the feeding speed was 12 rpm. Then, the mixture was plasticized by holding it at 190°C for 45 minutes and calendering it at 160°C and 500 kPa for 12 seconds to obtain a high-toughness composite resin film.

[0077] Example 4: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 4 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:90; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 10 kg of polylactic acid-base nanoparticles; the base is calcium hydroxide; the thickness of the polylactic acid is 5 nanometers; the particle size of the polylactic acid-base nanoparticles is 9 nanometers. 10 kg of graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers); 0.1 kg of whitening agent (Millad 3905 whitening agent); Opening agent (diatomaceous earth) 0.3 kg; Antioxidant (antioxidant 1010 and antioxidant 168 in a 3:4 mass ratio) 0.1 kg; Light stabilizer (light stabilizer 770) 0.5 kg.

[0078] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (the content of silica particles was 6wt%). Then, chitosan solution (concentration was 2wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 6.1. The mixture was coated at room temperature for 5 hours under stirring speed of 130 rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:120. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0079] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 17:4 and the mass ratio of silane coupling agent KH-550 to base of 10:2.4. The mixture was kneaded at 120 degrees Celsius for 6 minutes, granulated, cooled to room temperature by air at a cooling rate of 30℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0080] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 190 degrees Celsius for 11 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 220 rpm and the feeding speed was 11 rpm. Then, the material was plasticized by holding it at 180°C for 50 minutes and calendering it at 155°C and 400 kPa for 15 seconds to obtain a high-toughness composite resin film.

[0081] Example 5: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 6 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:105; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 12 kg of polylactic acid-base nanoparticles; the base is sodium carbonate or calcium hydroxide; the thickness of the polylactic acid is 4 nm; the particle size of the polylactic acid-base nanoparticles is 7.5 nm. Graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers) 9 kg; 0.4 kg of whitening agent (NA-11 whitening agent); Opening agent (talc) 0.5 kg; Antioxidant (antioxidant 1010 and antioxidant 168 in a 3:4 mass ratio) 0.1 kg; Light stabilizer (light stabilizer 770) 0.3 kg.

[0082] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (the content of silica particles was 6.3 wt%). Then, chitosan solution (concentration was 2.8 wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 5.9. The mixture was coated at room temperature for 4 hours under stirring speed of 130 rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:120. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0083] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 16:5 and the mass ratio of silane coupling agent KH-550 to base of 10:2. The mixture was kneaded at 110 degrees Celsius for 7 minutes, granulated, cooled to room temperature by air at a cooling rate of 30℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0084] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 190 degrees Celsius for 10 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 200 rpm and the feeding speed was 10 rpm. Then, the material was plasticized by holding it at 170°C for 55 minutes and calendering it at 155°C and 450 kPa for 15 seconds to obtain a high-toughness composite resin film.

[0085] Example 6: This embodiment prepares a high-toughness composite resin film using the following raw materials: Low-density polyethylene resin (density 0.91~0.93 g / cm³) 3 100 kg; 4 kg of chitosan-silica nanoparticles; the number average molecular weight of chitosan is 7000~15000; the mass ratio of silica to chitosan is 100:95; the particle size of chitosan-silica nanoparticles is 35~62 nanometers. 13 kg of polylactic acid-base nanoparticles; the base is sodium carbonate; the thickness of the polylactic acid is 4 nanometers; the particle size of the polylactic acid-base nanoparticles is 8 nanometers. Graphene nanosheets (thickness 6-8 nanometers, lateral dimensions 10-25 micrometers) 7 kg; 0.3 kg of whitening agent (Millad 3905 whitening agent); 0.5 kg of opening agent (diatomaceous earth); Antioxidant (antioxidant 1010 and antioxidant 168 in a 1:10 mass ratio) 0.2 kg; Light stabilizer (light stabilizer 770) 0.4 kg.

[0086] The specific preparation steps in this embodiment are as follows: (1) Preparation of chitosan-silica nanoparticles: Silica particles and phosphate buffer solution with pH 7.4 were mixed to obtain a dispersion (silica particle content was 5.5 wt%). Then, chitosan solution (concentration was 1.8 wt%) and acetic acid were mixed with the obtained dispersion. The pH of the system was 6. The mixture was coated at room temperature for 8 hours under stirring speed of 80 rpm. The mass ratio of chitosan in silica particles and chitosan solution was 100:120. After centrifugation and washing with water, chitosan-silica nanoparticles were obtained.

[0087] (2) Preparation of polylactic acid-base nanoparticles: The polylactic acid and base were mixed according to the mass ratio of polylactic acid to base of 20:3 and the mass ratio of silane coupling agent KH-550 to base of 10:1. The mixture was kneaded at 120 degrees Celsius for 5 minutes, granulated, cooled to room temperature by air at a cooling rate of 40℃ / min, crushed, and sieved to obtain polylactic acid-base nanoparticles.

[0088] (3) Mix low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer, and knead at 185 degrees Celsius for 9 minutes to obtain composite resin. (4) The prepared composite resin and polylactic acid-base nanoparticles were mixed and kneaded. The temperature gradient of the extruder was set to 150°C, 170°C, 180°C and 175°C. The die head temperature was 160°C, the screw speed was 190 rpm and the feeding speed was 11 rpm. Then, the material was plasticized by holding it at 175°C for 45 minutes and calendering it at 155°C and 450 kPa for 15 seconds to obtain a high-toughness composite resin film.

[0089] Comparative Example 1: The preparation method of this comparative example is the same as that of Example 1, except that the chitosan-silica nanoparticles are replaced with an equal mass of polylactic acid-base nanoparticles.

[0090] Comparative Example 2: The preparation method of this comparative example is the same as that of Example 1, except that the polylactic acid-base nanoparticles are replaced with an equal mass of chitosan-silica nanoparticles.

[0091] Comparative Example 3: The preparation method of this comparative example is the same as that of Example 1, except that the graphene nanosheets are replaced with an equal mass of chitosan-silica nanoparticles.

[0092] Test Example 1: The performance of the high-toughness composite resin films of Examples 1-6 and Comparative Examples 1-3 was tested. The testing methods included elongation at break according to QB 1259-91 standard and tensile strength according to GB / T1040.3-200 standard. Commercially available air cushion films were used as controls. The results are shown in Table 1 and... Figure 1 As shown.

[0093] Table 1. Test results of high-toughness composite resin films from Examples 1-6 and Comparative Examples 1-3:

[0094] According to Table 1 and Figure 1As can be seen, the high-toughness composite resin film provided by this invention exhibits excellent toughness, tensile strength, and puncture strength. Compared to comparative examples 1-3, the high-toughness composite resin film provided by this invention demonstrates particularly outstanding toughness, and also shows good performance in tensile strength and puncture strength. This indicates that the modified system constructed by this invention using chitosan-silica nanoparticles, polylactic acid-base nanoparticles, and graphene nanosheets plays a crucial role in improving the toughness of low-density polyethylene. This invention utilizes the synergistic effect of these three components to achieve the aforementioned superior properties, providing a new option for the transportation or packaging fields.

[0095] The embodiments of the present invention have been described above; however, these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A high-toughness composite resin film, characterized in that, It is prepared from the following parts by weight of raw materials: 100 parts low-density polyethylene resin, 3-7 parts chitosan-silica nanoparticles, 8-15 parts polylactic acid-alkali nanoparticles, 6-10 parts graphene nanosheets, 0.1-0.5 parts whitening agent, 0.3-0.6 parts opening agent, 0.1-0.3 parts antioxidant and 0.2-0.5 parts light stabilizer; The chitosan-silica nanoparticles include silica and chitosan coated on the surface of the silica; The polylactic acid-base nanoparticles comprise polylactic acid and a base distributed within the polylactic acid.

2. The high-toughness composite resin film according to claim 1, characterized in that, The chitosan-silica nanoparticles have a particle size of 35~62 nanometers; The mass ratio of silica to chitosan is 100:80~110.

3. The high-toughness composite resin film according to claim 1 or 2, characterized in that, The preparation method of the chitosan-silica nanoparticles includes the following steps: A dispersion was obtained by mixing silica particles and phosphate buffer solution, and then a chitosan solution and acid were mixed with the dispersion for coating. The amount of acid added should be such that the pH value of the system is not higher than 6.

2.

4. The high-toughness composite resin film according to claim 1, characterized in that, The polylactic acid-base nanoparticles have a particle size of 6-9 nanometers. The alkali is sodium carbonate or calcium hydroxide; The polylactic acid has a thickness of 3-5 nanometers.

5. The high-toughness composite resin film according to claim 1 or 4, characterized in that, The preparation method of the polylactic acid-base nanoparticles includes the following steps: After mixing polylactic acid, alkali and compatibilizer and kneading for 5-8 minutes, the mixture is granulated, cooled and crushed at a rate of 10-40℃ / min.

6. The high-toughness composite resin film according to claim 1, characterized in that, The graphene nanosheets have a thickness of 6-8 nanometers and a lateral dimension of 10-25 micrometers.

7. The method for preparing the high-toughness composite resin film according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Low-density polyethylene resin, chitosan-silica nanoparticles, graphene nanosheets, whitening agent, opening agent, antioxidant and light stabilizer are mixed and kneaded to obtain composite resin; (2) The composite resin and polylactic acid-base nanoparticles are mixed and kneaded, plasticized and calendered in sequence to obtain the high-toughness composite resin film.

8. The preparation method according to claim 7, characterized in that, The mixing conditions described in step (2) are: the extruder temperature gradient is set to 150°C, 170°C, 180°C and 175°C, and the die head temperature is 160°C; The screw speed is 150~250 rpm; The feeding speed is 8~12 rpm.

9. The preparation method according to claim 7, characterized in that, The plasticizing temperature is 160~190 degrees Celsius, and the holding time is 40~60 minutes.

10. An application of a high-toughness composite resin film in the transportation or packaging fields, characterized in that, The high-toughness composite resin film is the high-toughness composite resin film according to any one of claims 1 to 6 or the high-toughness composite resin film obtained by the preparation method according to any one of claims 7 to 9.

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