Environmentally friendly buffer anti-static bubble film and its preparation process

Abstract

The present invention relates to the technical field of layered materials, specifically to an environmentally friendly buffering antistatic bubble film and a preparation process thereof. The present invention overcomes the shortcomings of the existing buffering antistatic bubble film, namely, poor mechanical properties and poor flame retardant properties. The present invention obtains a special material for an anti-stretching layer, a special material for a flame retardant layer, a special material for a polyester layer, and a special material for a bubble layer by melt-blending the raw materials of each layer; the special material for an anti-stretching layer, the special material for a flame retardant layer, and the special material for a polyester layer are put into a three-layer co-extrusion film blowing machine, and a composite base film is obtained by film blowing; the special material for the bubble layer is used to prepare a bubble film layer; the anti-stretching layer of the composite base film and the flat base surface of the bubble film layer are hot-pressed to obtain a composite film; an antistatic coating is applied to the surface of the bubble film layer of the composite film, and after drying and curing, an environmentally friendly buffering antistatic bubble film is obtained. By adding fillers to each layer of the degradable polyester, the antistatic bubble film finally prepared has good mechanical properties and good flame retardant properties.

Description

Technical Field

[0001] The invention relates to the technical field of layered materials, in particular to an environmentally friendly buffering antistatic bubble film and a preparation process thereof. Background Art

[0002] Layered bubble films are widely used in product packaging. Traditional layered bubble films are mostly made from synthetic resins and have a certain cushioning and protective effect. However, with the increasing awareness of environmental protection, multi-layer bubble films made from degradable polyesters have gradually attracted attention. However, this type of multi-layer bubble film made from degradable polyester has obvious defects. In terms of mechanical properties, compared with traditional synthetic resin bubble films, its tensile strength and puncture resistance are relatively poor. During transportation and storage, it is easy to cause bubbles to rupture and the film to be damaged due to external forces, thereby reducing the protective effect of the product. In terms of flame retardant properties, degradable polyester multi-layer bubble films also perform poorly. In some usage scenarios with high requirements for fire safety, such as electronic product warehouses and chemical product transportation, once a fire occurs, its insufficient flame retardant ability may aggravate the spread of the fire and bring serious safety hazards.

[0003] Furthermore, in many practical applications, such as electronic component packaging, static electricity can damage delicate electronic components, leading to short circuits, performance degradation, and even component failure. Therefore, multi-layer bubble film made from biodegradable polyester urgently needs to possess antistatic properties. Given these numerous challenges, developing an environmentally friendly, buffering, antistatic bubble film with excellent mechanical properties, flame retardancy, and effective antistatic properties has become a pressing issue within the industry.

[0004] Therefore, an environmentally friendly buffer anti-static bubble film and its preparation process are proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide an environmentally friendly buffer anti-static bubble film and its preparation process. The present invention obtains a special material for an anti-stretching layer, a special material for a flame retardant layer, a special material for a polyester layer, and a special material for a bubble layer by melt-blending the raw materials of each layer; the special material for the anti-stretching layer, the special material for the flame retardant layer, and the special material for the polyester layer are put into a three-layer co-extrusion film blowing machine, and a composite base film is obtained by film blowing; the special material for the bubble layer is used to prepare a bubble film layer; the anti-stretching layer of the composite base film and the flat base surface of the bubble film layer are hot-pressed to obtain a composite film; an anti-static coating is applied to the surface of the bubble film layer of the composite film, and after drying and curing, an environmentally friendly buffer anti-static bubble film is obtained. By adding fillers to each layer of the degradable polyester, the anti-static bubble film finally prepared has good mechanical properties and good flame retardant properties.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In one aspect, the present invention provides an environmentally friendly buffer antistatic bubble film, which comprises a bubble film layer and a composite base film; the bubble film layer is coated with an antistatic coating; the composite base film comprises an anti-stretching layer, a flame retardant layer and a polyester layer;

[0008] The anti-stretching layer comprises poly (L-lactic acid), poly (D-lactic acid), epoxy silane coupling agent and magnesium hydroxide;

[0009] The flame retardant layer includes maleic anhydride, polybutylene adipate terephthalate, and modified wollastonite whiskers;

[0010] The polyester layer includes poly (L-lactic acid), poly (D-lactic acid), and multifunctional masterbatch;

[0011] The modified wollastonite whisker comprises wollastonite whisker, phosphate and aminosilane coupling agent;

[0012] Multifunctional masterbatch includes polybutylene adipate terephthalate, prepolymer, stearic acid, and hydrotalcite;

[0013] The prepolymer includes vinyl-terminated polydimethylsiloxane, methyl hydrogen silicone oil and octavinyl cage polysilsesquioxane.

[0014] On the other hand, the present invention provides a preparation process of an environmentally friendly buffer antistatic bubble film:

[0015] The raw materials of each layer are dried and mixed uniformly, and then put into a twin-screw extruder for melt blending to obtain a special material for the anti-stretching layer, a special material for the flame retardant layer, a special material for the polyester layer and a special material for the bubble layer;

[0016] The special materials for each layer are put into a three-layer co-extrusion film blowing machine, and the composite base film is produced by film blowing; the thickness of the tensile layer, the flame retardant layer, and the polyester layer are all 20 μm;

[0017] Prepare a bubble film layer using a special material for the bubble layer;

[0018] The anti-stretching layer of the composite base film and the flat base surface of the bubble film layer are hot-pressed to obtain a composite film; the hot pressing roller temperature is set to 135°C and the laminating pressure is 0.5MPa;

[0019] An antistatic coating is coated on the surface of the bubble film layer of the composite film, and after drying and curing, an environmentally friendly buffer antistatic bubble film is obtained.

[0020] Preferably, the preparation method of the special material for the tensile layer is as follows: by weight, 35 parts of poly (L-lactic acid), 35 parts of poly (D-lactic acid), 5 parts of chain extender, and 8-12 parts of pretreated magnesium hydroxide are put into a twin-screw extruder for melt blending and granulation, the temperatures of each zone of the extruder are 175°C, 190°C, 205°C, 215°C, and 210°C, and the screw speed is 160-200rpm; wherein the preparation method of the pretreated magnesium hydroxide is: 100 parts of magnesium hydroxide are added to a silane coupling agent hydrolyzate, and then the pH value is adjusted to 4.5 with glacial acetic acid, and the surface is treated to prepare the obtained material; the silane coupling agent hydrolyzate is prepared by adding 3-5 parts of KH560 to a mixture of 190 parts of anhydrous ethanol and 10 parts of water.

[0021] Preferably, the preparation method of the special material for the flame retardant layer is as follows: 50 parts of polybutylene adipate terephthalate, 2-4 parts of maleic anhydride, and 0.5 parts of dicumyl peroxide are mixed by weight, and then melt-blended and extruded to obtain maleic anhydride-grafted polybutylene adipate terephthalate, the temperatures of each zone of the extruder are 150°C, 165°C, 175°C, 170°C, and 165°C, and the screw speed is 200rpm; then 50 parts of maleic anhydride-grafted polybutylene adipate terephthalate, 20 parts of microcapsule ammonium polyphosphate, 10-14 parts of modified wollastonite whiskers, and 5 parts of pentaerythritol are melt-blended and granulated to obtain the special material for the flame retardant layer; the temperatures of each zone of the extruder are set to 140°C, 145°C, 150°C, 155°C, and 150°C, and the screw speed is set to 200-240rpm.

[0022] Preferably, the preparation method of the modified wollastonite whiskers is as follows: first, phosphate coating is performed, and 50 parts by weight of wollastonite whiskers (length 5-10 μm, diameter 0.5-2 μm) are ultrasonically treated at a power of 300 W for 15 minutes, dispersed in 200 parts of deionized water, and then 5-9 parts of ammonium dihydrogen phosphate are added. The pH value is adjusted to 6.5 and stirred for reaction for 2-2.5 hours; after the reaction is completed, the mixture is filtered, the solid is collected, washed, and dried to obtain phosphate pre-modified whiskers; second, silane treatment is performed, and 3 parts of KH550 and 0.05 parts of dibutyltin laurate are added to a mixture of 95 parts of anhydrous ethanol and 5 parts of deionized water, the pH value is adjusted to 4, and the mixture is stirred to obtain a hydrolyzate. The phosphate pre-modified whiskers are added to the hydrolyzate and stirred at 60 rpm for reaction for 2-2.5 hours. After the reaction is completed, the mixture is filtered, washed, and dried to obtain modified wollastonite whiskers.

[0023] Preferably, the preparation method of the special material for the polyester layer is as follows: by weight, 45 parts of poly (L-lactic acid), 45 parts of poly (D-lactic acid), 1 part of antioxidant 1010, and 1 part of ultraviolet absorber UV-531 are blended and granulated, and the temperatures of each zone of the extruder are 170°C, 185°C, 200°C, 210°C, and 205°C, respectively, and the screw speed is 150 rpm; then, the blend is blended and granulated again with 6-10 parts of multifunctional masterbatch to obtain the special material for the polyester layer, and the temperatures of each zone of the extruder are 175°C, 190°C, 205°C, 215°C, and 210°C, respectively, and the screw speed is 180-220 rpm; wherein the multifunctional masterbatch is prepared from poly (butylene adipate terephthalate), prepolymer, and pretreated hydrotalcite.

[0024] Preferably, the preparation method of the prepolymer is as follows: 13-17 parts by weight of vinyl-terminated polydimethylsiloxane and 3-5 parts of octavinyl cage polysilsesquioxane are added to 50 parts of toluene and stirred; under nitrogen protection, 0.02 parts of platinum catalyst are added, and then 2-3 parts of methyl hydrogen silicone oil (hydrogen content of 1.6%) are added; after the addition is complete, the reaction system is stirred for 4-4.5 hours; after the reaction is completed, the toluene solvent is removed by rotary evaporation and dried to obtain a prepolymer.

[0025] Preferably, the preparation method of the pretreated hydrotalcite is as follows: 5-9 parts by weight of stearic acid are added to 500 parts of anhydrous ethanol and heated to 60°C to dissolve to obtain a stearic acid ethanol solution, dry hydrotalcite is added to the stearic acid ethanol solution and stirred at 300 rpm for 3-3.5 hours, and then filtered, washed, and dried to obtain the pretreated hydrotalcite.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. In the present invention, in the tensile-resistant layer, a high-proportion stereocomplex polylactic acid matrix and pretreated magnesium hydroxide achieve efficient stress transfer through a strong chemically bonded interface. In the flame-retardant layer, a maleic anhydride-grafted polybutylene adipate terephthalate matrix forms a strong interface bond with modified wollastonite whiskers, giving full play to the reinforcing effect of the whiskers. In the heat-resistant polyester protective layer, the multifunctional masterbatch improves toughness and modulus through a cross-linked network and nano-reinforcement. The coordinated dosage of the components of each layer, the modification process, and the subsequent co-extrusion and hot-pressing composite process parameters ensure a gradient design from molecular modification to the mechanical function of the multilayer structure and interlayer synergy, ultimately improving the tensile strength and elongation at break of the bubble film.

[0028] 2. In the present invention, in the tensile strength layer, pretreated magnesium hydroxide forms a preliminary flame retardant barrier through endothermic decomposition. The core flame retardant / reinforced mechanical layer adopts a high-efficiency intumescent flame retardant system and innovatively introduces modified wollastonite whiskers. The phosphate coating layer catalyzes carbonization and together with the whisker skeleton enhances the structural stability and thermal insulation effect of the expanded carbon layer. The matrix modified by maleic anhydride grafting ensures the uniform dispersion and efficient synergy of each flame retardant component at the optimized processing temperature. In the heat-resistant polyester protective layer, the multifunctional masterbatch forms a synergistic flame retardant effect with the intermediate flame retardant layer through the in-situ formation of a silica ceramic protective layer and the endothermic decomposition of hydrotalcite. The multi-layer flame retardant design, combined with the selection, modification, and dosage of the components of each layer, ensures the orderly activation and efficient synergy of different flame retardant mechanisms, thereby improving the vertical combustion level of the bubble film.

[0029] 3. The core of this invention lies in the antistatic coating uniformly applied to the outermost layer of the bubble film. This coating utilizes a highly conductive aqueous dispersion of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid) as the conductive core, compounded with a water-based polyurethane emulsion as a highly effective film-forming agent and adhesion promoter, and a wetting agent to ensure excellent spreading on the biodegradable polyester surface. The water-based polyurethane not only enhances adhesion between the coating and the substrate, but also forms a flexible network that effectively encapsulates and stabilizes the conductive polymer, ensuring the integrity and durability of the conductive pathway. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a bar chart of the tensile strength test results of Example 1, Comparative Example 1, Comparative Examples 7-8, Comparative Example 10, and Comparative Examples 13-14 of the present invention;

[0031] Figure 2 This is a bar chart of the elongation at break test results of Example 1, Comparative Example 1, Comparative Examples 7-8, Comparative Example 10, and Comparative Examples 13-14 of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] See also Figures 1 to 2 The present invention provides an environmentally friendly buffer anti-static bubble film and its preparation process, and the technical solution is as follows:

[0034] In the present invention, the information of each substance is as follows: polybutylene adipate terephthalate (brand: Wuhan Shuer, CAS number: 55231-08-8), vinyl-terminated polydimethylsiloxane (brand: Kemik, model: Vi-PDMS), octavinyl cage polysilsesquioxane (brand: Fusman, product number: 9502034), methyl hydrogen silicone oil (manufacturer: Hubei Shuaiyan Ligao Biotechnology Co., Ltd.), and water-based polyurethane emulsion (brand: Hu Ling, model: WPU-8080).

[0035] Example 1

[0036] (1) Preparation of special materials for tensile strength layer

[0037] The invention discloses a method for preparing the pretreated magnesium hydroxide by adding 35 parts of poly (L-lactic acid), 35 parts of poly (D-lactic acid), 5 parts of an epoxy resin chain extender (Joncryl ADR 4468), and 8 parts of pretreated magnesium hydroxide into a twin-screw extruder for melt blending and granulation. The temperatures of the extruder zones are 175° C., 190° C., 205° C., 215° C., and 210° C., respectively, and the screw speed is 160 rpm. The pretreated magnesium hydroxide is prepared by adding 80 parts of magnesium hydroxide to a silane coupling agent hydrolyzate, adjusting the pH to 4.5 with glacial acetic acid, and performing surface treatment. The silane coupling agent hydrolyzate is prepared by adding 3 parts of KH560 to a mixture of 190 parts of anhydrous ethanol and 10 parts of water.

[0038] (2) Preparation of special materials for flame retardant layer

[0039] Preparation of modified wollastonite whiskers

[0040] First, phosphate coating is performed. 50 parts by weight of wollastonite whiskers (length 5-10 μm, diameter 0.5-2 μm) are ultrasonically treated at 300 W for 15 minutes, dispersed in 200 parts of deionized water, and then 5 parts of ammonium dihydrogen phosphate are added. The pH value is adjusted to 6.5 and the mixture is stirred and reacted for 2 hours. After the reaction, the mixture is filtered, the solid is collected, washed, and dried to obtain phosphate pre-modified whiskers. Second, silane treatment is performed. 3 parts of KH550 and 0.05 parts of dibutyltin laurate are added to a mixture of 95 parts of anhydrous ethanol and 5 parts of deionized water, the pH value is adjusted to 4, and the mixture is stirred to obtain a hydrolyzate. The phosphate pre-modified whiskers are added to the hydrolyzate and stirred at 60 rpm for 2 hours. After the reaction, the mixture is filtered, washed, and dried to obtain modified wollastonite whiskers.

[0041] By weight, 50 parts of polybutylene adipate terephthalate, 2 parts of maleic anhydride, and 0.5 parts of dicumyl peroxide were mixed and melt-blended and extruded to obtain maleic anhydride-grafted polybutylene adipate terephthalate. The temperatures of each zone of the extruder were 150° C., 165° C., 175° C., 170° C., and 165° C., and the screw speed was 200 rpm. Then, 50 parts of maleic anhydride-grafted polybutylene adipate terephthalate, 20 parts of microcapsule ammonium polyphosphate (Clariant, Exolit AP462), 10 parts of modified wollastonite whiskers, and 5 parts of pentaerythritol were melt-blended and granulated to obtain a special material for the flame retardant layer. The temperatures of each zone of the extruder were set to 140° C., 145° C., 150° C., 155° C., and 150° C., and the screw speed was set to 200 rpm.

[0042] (3) Preparation of special materials for polyester layer

[0043] Preparation of prepolymer

[0044] 15 parts by weight of vinyl-terminated polydimethylsiloxane and 3 parts of octavinyl cage polysilsesquioxane were added to 50 parts of toluene and stirred. Under nitrogen protection, 0.02 parts of platinum catalyst (1000 ppm of Custer catalyst) were added, and then 2 parts of methyl hydrogen silicone oil (hydrogen content of 1.6%) were added. After the addition was completed, the reaction system was stirred for 4 hours. After the reaction was completed, the toluene solvent was removed by rotary evaporation and dried to obtain a prepolymer.

[0045] Preparation of pretreated hydrotalcite

[0046] 5 parts by weight of stearic acid were added to 500 parts of anhydrous ethanol and heated to 60° C. to dissolve to obtain a stearic acid ethanol solution. 100 parts of dried hydrotalcite were added to the stearic acid ethanol solution and stirred at 300 rpm for 3 hours. After the reaction, the mixture was filtered, washed, and dried to obtain the pretreated hydrotalcite.

[0047] 80 parts of polybutylene adipate terephthalate (PBTA) and 5 parts of pretreated hydrotalcite were mixed and added to a twin-screw extruder. 15 parts of the prepolymer were injected into the second zone of the twin-screw extruder. The temperature profile of the twin-screw extruder was set at 140°C, 165°C, 180°C, and 170°C. The screw speed was controlled at 200 rpm. The blended extruded material was cooled, pelletized, and heat-treated in a 90°C oven for 3 hours to produce a multifunctional masterbatch.

[0048] By weight, 45 parts of poly (L-lactic acid), 45 parts of poly (D-lactic acid), 1 part of antioxidant 1010, and 1 part of ultraviolet absorber UV-531 were blended and granulated, and the temperatures of each zone of the extruder were 170°C, 185°C, 200°C, 210°C, and 205°C, and the screw speed was 150 rpm; then, the blend was blended and granulated again with 6 parts of multifunctional masterbatch to obtain a special material for the polyester layer, and the temperatures of each zone of the extruder were 175°C, 190°C, 205°C, 215°C, and 210°C, and the screw speed was 180 rpm.

[0049] (IV) Preparation of environmentally friendly buffer anti-static bubble film

[0050] The special materials for each layer were fed into a three-layer co-extrusion blown film machine with a material ratio of 1:1:1 for the three layers, and the composite base film was produced by blown film. The temperatures of the extruder zones of the tensile layer were set at 190°C, 200°C, 210°C, 220°C, and 230°C; the temperatures of the extruder zones of the flame retardant layer were set at 145°C, 150°C, 155°C, and 155°C; and the temperatures of the extruder zones of the polyester layer were set at 190°C, 200°C, 210°C, 220°C, and 230°C. The three melts passed through the co-extrusion blown film die head, and the die head temperature was set at 190°C. The thickness of the tensile layer, flame retardant layer, and polyester layer were all 20μm.

[0051] The bubble film layer was prepared from the bubble layer raw materials; 90 parts of polybutylene adipate terephthalate, 5 parts of polycaprolactone and 1 part of epoxy resin chain extender (Joncryl ADR 4400) were blended and extruded, and the temperatures of each zone of the extruder were 140°C, 155°C, 165°C, 160°C and 155°C, respectively, and the screw speed was 180 rpm to obtain a modified blend; then the modified blend was premixed with 2 parts of azodicarbonamide foaming agent, 2 parts of ultrafine talc (3000 mesh), 1 part of tributyl citrate and 0.5 parts of zinc oxide in a high-speed mixer at a speed of 1000 rpm for 10 minutes, and melt-plasticized through a single-screw extruder, and the temperatures of each zone of the extruder were set at 150°C, 165°C, 175°C and 185°C, and the die temperature was set at 185°C to obtain a bubble film layer; the bubble film had a thickness of 30 μm.

[0052] The anti-stretching layer of the composite base film and the flat base surface of the bubble film layer are hot-pressed to obtain a composite film; the hot pressing roller temperature is set to 135°C and the laminating pressure is 0.5MPa;

[0053] 0.1 part of a wetting agent (BYK-345) was added to 20 parts of deionized water to prepare a mixture. This mixture was then slowly added to 75 parts of a poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) aqueous dispersion (1.3% solids) under continuous stirring. Five parts of an aqueous polyurethane emulsion (50% solids) were then added with stirring. The pH of the coating was adjusted to 6.5 and stirred for 30 minutes to obtain an antistatic coating. The antistatic coating was then applied to the bubble film layer of the composite film. After drying and curing, an environmentally friendly, buffered, antistatic bubble film was obtained.

[0054] The difference between Example 2 and Example 1 is that, in the preparation process of pretreated magnesium hydroxide, the amount of KH560 added is 4 parts; in the preparation process of modified wollastonite whiskers, the amount of ammonium dihydrogen phosphate added is 7 parts, and the reaction time after the addition of ammonium dihydrogen phosphate is 2.3 hours, and the phosphate pre-modified whiskers are added to the hydrolyzate and stirred at 60rpm for 2.3 hours; in the preparation process of maleic anhydride grafted polybutylene adipate terephthalate, the amount of maleic anhydride added is 3 parts; in the preparation process of the prepolymer, 15 parts of vinyl-terminated polydimethylsiloxane, 4 parts of octavinyl cage-shaped polysilsesquioxane, and 2.5 parts of methyl hydrogen silicone oil are added, and the reaction system is stirred for 4.3 hours; in the preparation process of pretreated hydrotalcite, the amount of stearic acid added is 7 parts, and the stirring reaction time is 3.3 hours.

[0055] The difference between Example 3 and Example 1 is that, in the preparation process of pretreated magnesium hydroxide, the amount of KH560 added is 5 parts; in the preparation process of modified wollastonite whiskers, the amount of ammonium dihydrogen phosphate added is 9 parts, and the reaction time after the addition of ammonium dihydrogen phosphate is 2.5 hours, and the phosphate pre-modified whiskers are added to the hydrolyzate and stirred at 60rpm for 2.5 hours; in the preparation process of maleic anhydride grafted polybutylene adipate terephthalate, the amount of maleic anhydride added is 4 parts; in the preparation process of the prepolymer, 17 parts of vinyl-terminated polydimethylsiloxane, 5 parts of octavinyl cage-shaped polysilsesquioxane, and 3 parts of methyl hydrogen silicone oil are added, and the reaction system is stirred for 4.5 hours; in the preparation process of pretreated hydrotalcite, the amount of stearic acid added is 9 parts, and the stirring reaction time is 3.5 hours.

[0056] The difference between Example 4 and Example 2 is that, in the preparation process of the special material for the tensile layer, 10 parts of pretreated magnesium hydroxide are used and the screw speed is 200 rpm; in the preparation process of the special material for the flame retardant layer, 12 parts of modified wollastonite whiskers are used and the screw speed is 220 rpm; in the preparation process of the special material for the polyester layer, 8 parts of the multifunctional masterbatch are added and the screw speed is 200 rpm.

[0057] The difference between Example 5 and Example 2 is that, in the preparation process of the special material for the anti-tensile layer, 12 parts of pretreated magnesium hydroxide are used; in the preparation process of the special material for the flame retardant layer, 14 parts of modified wollastonite whiskers are used, and the screw speed is 240 rpm; in the preparation process of the special material for the polyester layer, the amount of multifunctional masterbatch added is 10 parts, and the screw speed is 220 rpm.

[0058] The only difference between Comparative Example 1 and Example 1 is that no pretreated magnesium hydroxide is added to the special material for the tensile layer.

[0059] The only difference between Comparative Example 2 and Example 1 is that no modified wollastonite crystals are added to the special material for the flame retardant layer.

[0060] The only difference between Comparative Example 3 and Example 1 is that no multifunctional masterbatch is added to the special material for the polyester layer.

[0061] The only difference between Comparative Example 4 and Example 1 is that no pretreated magnesium hydroxide is added to the special material for the tensile layer; and no modified wollastonite crystals are added to the special material for the flame retardant layer.

[0062] Comparative Example 5 differs from Example 1 only in that no pretreated magnesium hydroxide is added to the special material for the stretching layer; and no multifunctional masterbatch is added to the special material for the polyester layer.

[0063] The only difference between Comparative Example 6 and Example 1 is that no modified wollastonite crystals are added to the special material for the flame retardant layer; and no multifunctional masterbatch is added to the special material for the polyester layer.

[0064] Comparative Example 7 differs from Example 1 only in that unpretreated magnesium hydroxide is added to the special material for the tensile layer; and unmodified wollastonite whiskers are added to the special material for the flame retardant layer.

[0065] The only difference between Comparative Example 8 and Example 1 is that the modified wollastonite crystals in the special material for the flame retardant layer are not treated with silane.

[0066] The only difference between Comparative Example 9 and Example 1 is that the modified wollastonite crystals in the special material for the flame retardant layer are not coated with phosphate.

[0067] The only difference between Comparative Example 10 and Example 1 is that in the special material for the flame retardant layer, polybutylene adipate terephthalate is not treated with maleic anhydride.

[0068] The only difference between Comparative Example 11 and Example 1 is that no prepolymer is added to the multifunctional masterbatch used in the special material for the polyester layer.

[0069] The only difference between Comparative Example 12 and Example 1 is that no pretreated hydrotalcite is added to the multifunctional masterbatch used in the special material for the polyester layer.

[0070] The only difference between Comparative Example 13 and Example 1 is that during the preparation of the multifunctional masterbatch, the prepolymer, polybutylene adipate terephthalate and pretreated hydrotalcite were blended and added.

[0071] Comparative Example 14 differs from Example 1 only in that when preparing the special material for the polyester layer, the multifunctional masterbatch is mixed and granulated with poly (L-lactic acid), poly (D-lactic acid), antioxidant 1010, and ultraviolet absorber UV-531 at one time.

[0072] The only difference between Comparative Example 15 and Example 1 is that no antistatic coating was applied.

[0073] Test Example 1

[0074] Test objects: The bubble films prepared in Examples 1-5 and Comparative Examples 1, 7-8, 10, and 13-14 were tested.

[0075] Test method: Tensile strength and elongation at break were tested in accordance with GB / T13022-1991 "Test method for tensile properties of plastic films". The final test results are shown in Table 1 and Figure 1-Figure 2 shown.

[0076] Table 1 Tensile strength and elongation at break test results

[0077]

[0078] In comparative example 1, the tensile strength layer lacks pre-treatment magnesium hydroxide, so that the polylactic acid matrix and the filler lack effective chemical bonding interface, and stress transmission is hindered, causing the mechanical support effect of this layer to weaken. In comparative example 7, magnesium hydroxide is without pre-treatment and wollastonite whisker is without modification, causing the filler and polymer matrix interface bonding force in the two key layers to all decline, and interface defects increase, and the material is prone to early destruction when stressed. In comparative example 8, the flame retardant layer modified wollastonite whisker lacks silane treatment, weakens the strong interface coupling formed by the reaction of amino and anhydride groups between it and the maleic anhydride grafted polybutylene adipate terephthalate matrix, and reduces the mechanical strengthening effect of this layer. In comparative example 10, the flame retardant layer polybutylene adipate terephthalate matrix is ​​not modified by maleic anhydride grafting, causing the interface compatibility and bonding strength of it and polar modified wollastonite whisker to be insufficient, even if whisker is also difficult to effectively enhance non-polar matrix after treatment. In Comparative Example 13, the multifunctional masterbatch was prepared by one-time blending rather than precise step-by-step addition, which may have affected the formation of the micro-crosslinked network structure of the vinyl functionalized silicone-POSS prepolymer in the matrix and the effective dispersion of the POSS nanocages, thereby weakening the masterbatch's improvement in the toughness and modulus of the polyester layer. In Comparative Example 14, the one-time mixing and granulation of the polyester layer-specific material may have interfered with the perfection of the stereocomposite crystallization of poly (L-lactic acid) and poly (D-lactic acid), weakened the inherent strength and heat resistance of the polylactic acid matrix itself, and may have affected the dispersion and interfacial interaction of the multifunctional masterbatch therein.

[0079] This group of comparative examples demonstrates the importance of interface synergy and process optimization for maximizing the mechanical properties of materials. Comparative Examples 1, 7, 8, and 10 all point out from different levels that the interface is the key to determining the mechanical properties of composite materials: Comparative Example 1 directly verifies the negative impact of the lack of beneficial interfaces; Comparative Example 7 demonstrates the cumulative degradation effect when multiple interfaces are not optimized; Comparative Examples 8 and 10 respectively confirm the necessity of building a strong interface from the perspectives of filler surface treatment and matrix modification. The lack of any link will lead to a loss of mechanical properties. These comparative examples jointly emphasize that simple physical filling cannot achieve efficient reinforcement, and the interaction between filler and matrix must be optimized through precise chemical and physical means. Furthermore, Comparative Examples 13 and 14 demonstrate the influence of microstructure on macroscopic mechanical properties from a process level. Comparative Example 13 illustrates that whether the components inside the masterbatch can form the expected synergistic reinforcement structure depends on whether its preparation process can ensure the orderly interaction and uniform dispersion of the components. Comparative Example 14 demonstrates that even high-performance matrix and functional masterbatch cannot fully realize their potential if the final blending and granulation process fails to fully consider the formation dynamics and interactions of each component. Therefore, this set of comparative examples illustrates that the mechanical properties of the present invention are the result of multi-dimensional synergistic optimization, from material selection, surface modification, to processing technology.

[0080] Test Example 2

[0081] Test objects: The bubble films prepared in Examples 1-5 and Comparative Examples 2-6, Comparative Example 9, and Comparative Examples 11-12 were tested.

[0082] Test method: The vertical burning rating of the bubble film was tested using the UL94 flame retardant rating test. The final test results are shown in Table 2.

[0083] Table 2 Test results

[0084]

[0085] In Comparative Example 2, the flame retardant layer lacks modified wollastonite whiskers, which causes the expanded carbon layer to lose the catalytic effect of the phosphate coating on its carbonization process and the enhancement of its structural stability by the whisker skeleton, making it difficult to form an effective heat-insulating and oxygen-isolating barrier. In Comparative Example 3, the polyester layer lacks a multifunctional masterbatch, which causes it to lose the silicon oxide ceramic protective layer formed in situ by the organosilicon-POSS and the synergistic flame retardant contribution of the gas phase and condensed phase brought about by the endothermic decomposition of hydrotalcite. Comparative Examples 4, 5, and 6 respectively remove the key flame retardant components in the tensile layer, flame retardant layer, and polyester layer by combining them. The lack of the superimposed contribution of these components to the overall flame retardant performance leads to the loss of multi-dimensional gradient flame retardant function. In Comparative Example 9, the flame retardant layer modified wollastonite whiskers are not treated with phosphate coating, which causes them to lose the key function of converting to form substances such as calcium pyrophosphate at high temperature to catalyze the polymer into carbon and improve the thermal stability of the carbon layer. Even if the whisker skeleton is still there, the quality of the carbon layer is greatly reduced. In Comparative Example 11, the polyester layer multifunctional masterbatch lacked the vinyl-functionalized organosilicon-POSS prepolymer, preventing it from forming a thermally stable silicone ceramic protective layer during combustion, thus weakening the condensed-phase flame retardant contribution of this layer. In Comparative Example 12, the polyester layer multifunctional masterbatch lacked the pretreated hydrotalcite, eliminating its vapor-phase synergistic flame retardant mechanism, which dilutes combustible gases and reduces surface temperature through endothermic decomposition and the release of water vapor.

[0086] This group of comparative examples are interrelated and together demonstrate the synergistic effect of the components in the gradient flame retardant system of the present invention. Comparative Examples 2 and 3 directly prove that the modified wollastonite whiskers in the flame retardant layer and the multifunctional masterbatch in the polyester layer are the core elements for achieving efficient flame retardancy, and the lack of any one of them will lead to a significant decrease in flame retardant properties. Comparative Examples 4, 5, and 6 further emphasize the importance of the synergistic effect of the flame retardant components in the multilayer structure; for example, in Comparative Example 4, the preliminary barrier of the anti-tensile layer and the core carbonization enhancement of the flame retardant layer are simultaneously removed, causing the material to lose effective protection at the initial stage of combustion. Comparative Examples 9, 11, and 12 illustrate the influence of key modifications or ingredients within specific functional components on flame retardant properties: Comparative Example 9 shows that phosphate coating is the core of giving wollastonite whiskers the ability to catalyze carbonization. Without it, the flame retardant synergistic effect of the whiskers is greatly reduced; Comparative Examples 11 and 12 respectively illustrate that the porcelain-forming effect of the prepolymer in the multifunctional masterbatch and the endothermic decomposition effect of hydrotalcite are the key sources of their synergistic flame retardant function. These comparative examples collectively prove that the flame-retardant design of the present invention is not a simple stacking of flame retardants, but is based on the different stages and different action mechanisms of each component in the combustion process, achieving multi-level and multi-dimensional synergistic flame retardancy from the initial barrier of the outer layer to the efficient expansion and carbonization of the middle layer to the ceramic protection of the inner layer and the synergy of the gas phase.

[0087] Test Example 3

[0088] The surface resistance values ​​of the bubble films prepared in Example 1 and Comparative Example 15 were tested.

[0089] Table 3 Surface resistance test results

[0090]

[0091] The only difference from Example 1 is that no antistatic coating is applied, which directly results in the loss of the continuous and efficient conductive network constructed by the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid aqueous dispersion on the bubble film surface. Without this coating, the biodegradable polyester material of the outermost layer of the bubble film, such as polybutylene adipate terephthalate, is itself a polymer insulator and lacks freely mobile charge carriers. Its inherent volume resistivity and surface resistivity are extremely high. Therefore, when static charges are generated on the surface, these charges cannot be quickly dissipated or neutralized through the conductive path and will accumulate on the surface in large quantities, causing the surface resistance value to rise sharply to the level of insulating materials, far exceeding the antistatic level.

[0092] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly buffer anti-static bubble film, characterized by: The environmentally friendly buffer anti-static bubble film comprises a bubble film layer and a composite base film; the surface of the bubble film layer is coated with an anti-static coating; the composite base film comprises an anti-stretching layer, a flame retardant layer and a polyester layer; The anti-stretching layer comprises poly (L-lactic acid), poly (D-lactic acid), epoxy silane coupling agent, and pretreated magnesium hydroxide; The flame retardant layer comprises maleic anhydride grafted polybutylene adipate terephthalate and modified wollastonite whiskers; The polyester layer comprises the poly (L-lactic acid), the poly (D-lactic acid), and a multifunctional masterbatch; The modified wollastonite whiskers include wollastonite whiskers, phosphate, and aminosilane coupling agent; The multifunctional masterbatch comprises polybutylene adipate terephthalate, a prepolymer, stearic acid, and hydrotalcite; The prepolymer comprises vinyl-terminated polydimethylsiloxane, methyl hydrogen silicone oil and octavinyl cage-like polysilsesquioxane; The preparation method of the pretreated magnesium hydroxide is as follows: adding magnesium hydroxide to a silane coupling agent hydrolyzate and performing surface treatment under acidic conditions to obtain the magnesium hydroxide; The preparation method of the maleic anhydride grafted polybutylene adipate terephthalate comprises: blending polybutylene adipate terephthalate, maleic anhydride, and dicumyl peroxide and extruding to obtain the maleic anhydride grafted polybutylene adipate terephthalate; The preparation method of the modified wollastonite whiskers comprises the following steps: firstly, phosphate coating is performed, wollastonite whiskers are ultrasonically dispersed in deionized water, ammonium dihydrogen phosphate is added, and the pH value is adjusted and then stirred for reaction; after the reaction is completed, filtering is performed, solids are collected, washed, and dried to obtain phosphate pre-modified whiskers; The second step is silane treatment, KH-550 and dibutyltin laurate are added to a mixture of ethanol and deionized water, the pH value is adjusted, and the mixture is stirred to obtain a hydrolyzate, the phosphate pre-modified whiskers are added to the hydrolyzate and stirred for reaction, and after the reaction is completed, the mixture is filtered, washed, and dried to obtain the modified wollastonite whiskers; The multifunctional masterbatch is prepared from polybutylene adipate terephthalate, a prepolymer, and pretreated hydrotalcite; The preparation method of the prepolymer comprises: adding vinyl-terminated polydimethylsiloxane and octavinyl cage-shaped polysilsesquioxane to toluene and stirring; adding a platinum catalyst under nitrogen protection; and then adding methyl hydrogen silicone oil; after the addition is complete, stirring the reaction system to react; after the reaction is completed, removing the toluene solvent by rotary evaporation and drying to obtain the prepolymer; The preparation method of the pretreated hydrotalcite comprises the following steps: adding stearic acid to anhydrous ethanol and heating to dissolve to obtain a stearic acid ethanol solution; adding dry hydrotalcite to the stearic acid ethanol solution and stirring to react; filtering, washing, and drying to obtain the pretreated hydrotalcite.

2. A process for preparing the environmentally friendly buffer antistatic bubble film according to claim 1, characterized in that: The raw materials of each layer are dried and mixed, and then put into a twin-screw extruder for melt blending to obtain a special material for the anti-stretching layer, a special material for the flame retardant layer, a special material for the polyester layer and a special material for the bubble layer; Putting the special material for the anti-stretching layer, the special material for the flame retardant layer, and the special material for the polyester layer into a three-layer co-extrusion film blowing machine, and blowing the film to obtain a composite base film, wherein the composite base film includes the anti-stretching layer, the flame retardant layer, and the polyester layer; Using the special material for the bubble layer to prepare the bubble film layer; Hot-pressing the anti-stretching layer of the composite base film and the flat base surface of the bubble film layer to obtain a composite film; An antistatic coating is coated on the surface of the bubble film layer of the composite film, and after drying and curing, the environmentally friendly buffer antistatic bubble film is obtained.

3. The preparation process of the environmentally friendly buffer antistatic bubble film according to claim 2, characterized in that: The preparation method of the special material for the anti-stretching layer is as follows: poly (L-lactic acid), poly (D-lactic acid), a chain extender, and pretreated magnesium hydroxide are put into a twin-screw extruder for melt blending and granulation.

4. The process for preparing the environmentally friendly buffer antistatic bubble film according to claim 2, characterized in that: The preparation method of the flame retardant layer special material is as follows: the maleic anhydride grafted polybutylene adipate terephthalate is melt-blended and granulated with microcapsule ammonium polyphosphate, modified wollastonite whiskers and pentaerythritol to obtain the flame retardant layer special material.

5. The process for preparing the environmentally friendly buffer antistatic bubble film according to claim 2, characterized in that: The preparation method of the polyester layer special material is: poly (L-lactic acid), poly (D-lactic acid), antioxidant 1010, and ultraviolet absorber UV-531 are blended and granulated, and then the blend is blended and granulated again with multifunctional masterbatch to obtain the polyester layer special material.

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