Environmentally Friendly Multifunctional PVB Film and Its Preparation Method

Abstract

The present invention discloses an environment-friendly multifunctional PVB film and a preparation method thereof. The PVB film comprises PVB resin, a plasticizer, an antioxidant, and modified hollow glass microspheres. In the present invention, the etched hollow glass microspheres are modified by a modifier, and then embedded into a honeycomb-like porous structure by a sizing agent to achieve physical and chemical coating effects, forming a new interface layer. Finally, the modified hollow glass microspheres are melt-blended to prepare the PVB film. Compared with the prior art, the environment-friendly multifunctional PVB film prepared by the present invention has good flame retardant properties.

Description

Technical Field

[0001] The present invention relates to the technical field of functional film materials, and particularly relates to an environmentally friendly multifunctional PVB film and a preparation method thereof. Background Art

[0002] The origin of PVB film can be traced back to the middle of the last century. With the development of the chemical industry, scientists began to explore modification methods of polyvinyl alcohol in order to obtain new materials with more excellent properties. Through the acetalization reaction, PVB film came into being. It not only retains the original advantages of polyvinyl alcohol, such as good hydrophilicity, film-forming property, etc., but also obtains higher heat resistance, weather resistance and impact resistance. The combination of these characteristics enables PVB film to quickly find its application in many fields such as construction, automotive, electronics, optics, etc. Through the acetalization reaction, PVB film came into being. It not only retains the original advantages of polyvinyl alcohol, such as good hydrophilicity, film-forming property, etc., but also obtains higher heat resistance, weather resistance and impact resistance. The combination of these characteristics enables PVB film to quickly find its application in many fields such as construction, automotive, electronics, optics, etc.

[0003] In the construction field, PVB film is used as the interlayer material of safety glass. Through its strong adhesion, two or more pieces of glass are firmly bonded together to form composite safety glass. When this kind of glass is impacted by external force, even if it breaks, the fragments will be tightly adhered by the PVB film and will not fly and hurt people, thus greatly improving the safety of the building.

[0004] In the automotive industry, PVB film plays an indispensable role. It is widely used in the manufacture of automotive front windshield and side window glass, not only providing excellent impact resistance, but also effectively blocking ultraviolet rays to protect the health of drivers and passengers. In addition, PVB film also has good sound insulation effect, which helps to improve the driving comfort of the vehicle.

[0005] In the optical field, PVB film has high transparency, low refractive index and stability, making it one of the ideal materials for manufacturing optical components. Whether it is a lens, a prism or a filter, PVB film can provide excellent optical performance to meet the needs of precision optical instruments.

[0006] With the progress of technology and the enhancement of environmental protection awareness, the application fields of PVB film are still expanding. In the new energy field, PVB film is used as the encapsulation material of solar panels, and its excellent weather resistance and adhesion ensure the long-term stability and service life of the panels. In terms of environmental protection materials, scientists are also actively exploring the preparation technology of degradable PVB film in order to achieve the recycling of materials and reduce environmental pollution.

[0007] CN114437482A discloses a special material for PVB film, its preparation method and application, which comprises the following components in parts by weight: polyvinyl butyral, hydrophobic amorphous nano-silica, and plasticizer. Through the blending of maleic anhydride-styrene alternating copolymer microspheres and fumed silica, the fumed silica has hydrophobicity and is evenly dispersed in the polymer matrix. The special material for PVB film prepared by this method has better weather and moisture resistance and heat preservation performance, and is widely used in photovoltaic thin-film solar cell modules, laminated glass, interlayer films, adhesives, etc. However, the PVB film prepared by this method has poor thermal stability.

[0008] CN118240318B discloses a high-strength heat-insulating PVB film and its preparation method. The modified reinforced aerogel, PVB resin, plasticizer and antioxidant are mixed evenly and granulated by a twin-screw extruder. This invention uses the modified reinforced aerogel to enhance the heat insulation of the PVB film, and at the same time, it also has a certain improvement in mechanical properties; the modified reinforced aerogel uses cellulose fibrils as raw materials. As the fibrillation degree of cellulose fibrils increases, more hydroxyl groups are exposed, forming tight hydrogen bonds between the fibrils, constituting the stability of the network structure. The internal porosity of the formed aerogel is high, making the air inside the aerogel close to the inner wall of the pores and in a relatively static state. The thermal resistance of air is high and it is not conducive to heat conduction, so the thermal conductivity is low and it has excellent heat insulation performance. However, when the PVB film prepared by this method encounters a fire, it is extremely easy to burn and there will be many potential safety hazard problems. Summary of the Invention

[0009] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to improve the flame retardant performance of the environmentally friendly multifunctional PVB film and reduce the potential safety hazard problems in case of fire.

[0010] Since hollow glass microspheres are spherical and have the smallest surface area in nature for the same volume, this basic characteristic endows them with physical and chemical properties that many lightweight fillers cannot match, such as high compressive strength, high melting point, high resistivity, etc. Due to the unique hollow structure, it has properties such as light weight and sound insulation, and is known as the space material of the new era. In order to improve the performance of PVB materials, reduce costs and meet specific application requirements, hollow glass microspheres are added to the PVB film. However, when hollow glass microspheres are mixed into PVB resin, the compatibility between the two is poor, and there will be obvious poor interfaces after curing. Therefore, it is considered to modify the hollow glass microspheres. The hollow glass microspheres are modified by a modifier and then coated with a sizing agent to prepare modified hollow glass microspheres. Then, the modified hollow glass microspheres are blended with the PVB film, which is beneficial to improving the mechanical properties and thermal stability of the PVB film, and at the same time can also increase the flame retardant effect of the PVB film.

[0011] To achieve the above object, the present invention provides an environmentally friendly multifunctional PVB film and a preparation method thereof.

[0012] An environmentally friendly multifunctional PVB film, calculated by weight, comprises the following components: 80-120 parts of PVB resin, 10-25 parts of plasticizer, 1-5 parts of antioxidant, 10-30 parts of modified hollow glass microspheres, and the modified hollow glass microspheres are prepared from etched hollow glass microspheres, sizing agent and modifier.

[0013] Preferably, the preparation method of the modified hollow glass microspheres comprises the following steps:

[0014] S1. Add the modifier to water, stir at 200-500 rpm for 10-30 min, add the etched hollow glass microspheres, and stir at room temperature for 1-3 h to obtain a uniform mixture;

[0015] S2. Add the sizing agent to the uniform mixture, stir evenly at room temperature for 1-3 h, perform suction filtration, drying, and cool to room temperature to obtain the modified hollow glass microspheres.

[0016] More preferably, the preparation method of the modified hollow glass microspheres comprises the following steps, calculated by weight:

[0017] S1. Add 1-8 parts of modifier to 100-400 parts of water, stir at 200-500 rpm for 10-30 min, add 10-50 parts of etched hollow glass microspheres, and stir at room temperature for 1-3 h to obtain a uniform mixture;

[0018] S2. Then add 1-8 parts of sizing agent to the uniform mixture, stir at room temperature for 1-3 h, then perform suction filtration on the mixture, drying, and cool to room temperature to obtain the modified hollow glass microspheres.

[0019] Preferably, the sizing agent is any one of 1,4-butanediol diacrylate, 4-hydroxybutyl acrylate, and phosphonyl undecylenic acid propionate.

[0020] More preferably, the sizing agent is phosphonyl undecylenic acid propionate.

[0021] Preferably, the modifier is any one of 3-[tris(1-methylethoxy)silyl]propyl methacrylate, 3-[2-hydroxyethoxy(dimethoxy)silyl]propyl 2-methyl-2-propenoate, and N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane.

[0022] Preferably, the plasticizer is one or more of trimellitate esters, adipate esters, maleate esters, benzoate esters, and phosphate esters.

[0023] Preferably, the antioxidant is one or more of antioxidant 1076, antioxidant 168, and antioxidant 264.

[0024] The present invention also discloses a preparation method of an environmentally friendly multifunctional PVB film.

[0025] A preparation method of an environmentally friendly multifunctional PVB film includes the following steps, by weight:

[0026] Mix 80 - 120 parts of PVB resin, 10 - 25 parts of plasticizer, 1 - 5 parts of antioxidant, and 10 - 30 parts of modified hollow glass microspheres evenly, plasticize at 150 - 175 °C, and form a film through a mold to obtain an environmentally friendly multifunctional PVB film.

[0027] In this formulation, each raw material and its function are as follows:

[0028] As the main component of the film, PVB resin provides the basic physical properties and structural integrity of the film, such as good toughness, adhesiveness, and transparency.

[0029] The plasticizer mainly plays a role in regulating and improving the flexibility and processing performance of the environmentally friendly multifunctional PVB film.

[0030] The antioxidant mainly plays a role in protecting the environmentally friendly multifunctional PVB film from oxidative degradation.

[0031] By etching the hollow glass beads, their surfaces become rough, increasing the interfacial bonding force between them and the PVB resin matrix, enabling the microspheres to be more effectively dispersed and firmly embedded in the film material, thus significantly enhancing the tensile strength, toughness, and wear resistance of the film. At the same time, the cavity structure inside the hollow glass microspheres endows the film material with good heat insulation and sound insulation properties. The increase in the hydroxyl content on the surface of the etched hollow glass microspheres is beneficial for reacting with the modifier to form covalent bonds.

[0032] The modifier contains silane and double bonds. By introducing the modifier, functional groups or side chains that interact with the PVB resin molecular chains can be introduced on the surface of the microspheres, thereby enhancing the chemical bonding or physical adsorption between the microspheres and the resin. This modification not only helps to improve the dispersion uniformity and stability of the modified hollow glass microspheres in the PVB film but also significantly increases the tensile strength and toughness of the film material.

[0033] The sizing agent is added to the etched hollow glass microspheres mixed with the modifier, and then stirred at room temperature for a long time. The sizing agent can fully wet and coat the surface of the microspheres, improve the surface polarity of the material, enhance the wettability and bonding strength between the PVB polymer matrix and its surface. The sizing agent can also form covalent bonds with the active groups on the hollow glass microspheres modified by the modifier through chemical cross-linking, playing a "bridging role" to form a firm chemical bonding or physical adsorption layer. This coating not only improves the surface roughness of the microspheres, increases the contact area and interaction force with the PVB resin, but also promotes the fusion of the microspheres and the resin matrix during the subsequent plasticization process, thus significantly improving the mechanical properties, heat resistance and weather resistance of the environmentally friendly multifunctional PVB film.

[0034] Advantages of the present invention:

[0035] Compared with the prior art, the etched hollow glass microspheres are modified by a modifier containing double bonds and silanes, and then the sizing agent is embedded into the honeycomb-like porous structure to achieve a coating effect. At the same time, the double bonds contained in the sizing agent can further react with the hollow glass microspheres modified by the modifier, thereby coating the etched hollow glass microspheres to form a new interface layer, which is beneficial to improving the compatibility between the modified hollow glass microspheres and the PVB resin. Specific embodiments

[0036] Parameters and sources of specific chemical substances used.

[0037] Phosphonoundecyl acrylate, 11-Phosphonoundecyl acrylate, CAS No.: 915376-49-7.

[0038] 3-[2-Hydroxyethoxy(dimethoxy)silyl]propyl 2-methyl-2-propenoate, 2-methyl-2-propenoic acid 3-[2-hydroxyethoxy(dimethoxy)silyl]propyl ester, CAS No.: 29888-36-6.

[0039] N-(3-Methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane

[0040] [2-Hydroxy-3-(3-triethoxysilylpropylamino)propyl] 2-methylprop-2-enoate, CAS No.: 96132-98-8.

[0041] PVB resin, product number: P29692 - 100g, M.W. 170,000 - 250,000, brand: Acmec, Shanghai Jizhi Biochemical Technology Co., Ltd.

[0042] Antioxidant 1076, BASF.

[0043] Hollow glass microspheres, thermal conductivity: 0.028 - 0.070 (W / m·K), impurities ≤ 0.04%, compressive strength: 1.5 - 123 Mpa, porosity: 0.03%, refractoriness under load: 630 °C, Mohs hardness: 7.0, Hebei Houkang Mineral Products Co., Ltd.

[0044] Butyl acrylate, product number: DH05286, Hubei Dahao Chemical Co., Ltd.

[0045] Example 1

[0046] A preparation method of an environmentally friendly multifunctional PVB film, comprising the following steps:

[0047] Mix 100 kg of PVB resin, 12 kg of dioctyl adipate, 2 kg of antioxidant 1076, and 20 kg of modified hollow glass microspheres evenly, stir at 3000 rpm for 20 min, plasticize at 165 °C, and form a film through a mold to prepare an environmentally friendly multifunctional PVB film.

[0048] Among them, the preparation method of the modified hollow glass microspheres comprises the following steps:

[0049] S1. Add 4 kg of N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane to 100 L of water, stir at 300 rpm for 20 min, add 40 kg of etched hollow glass microspheres, and stir at 25 °C for 2 h to obtain a homogeneous mixture;

[0050] S2. Add 5 kg of phosphonyl undecylenyl acrylate to the homogeneous mixture, stir at 25 °C for 2 h, filter by suction for 8 min, dry at 80 °C for 12 h, and cool to 25 °C to obtain the modified hollow glass microspheres.

[0051] Among them, the preparation method of the etched hollow glass microspheres comprises the following steps:

[0052] Mix 4 kg of sodium hydroxide and 100 L of water, stir at 200 rpm for 10 min, then add 10 kg of hollow glass microspheres, stir and reflux at 80 °C for 6 h, then let stand for 2 h, take the upper-layer hollow glass microspheres for suction filtration, and wash with water until the pH is 7, and then dry at 100 °C for 12 h to obtain the etched hollow glass microspheres.

[0053] Example 2

[0054] The difference between Example 2 and Example 1 of this application is that the phosphonyl undecylenyl propionate in Example 1 is replaced by 1,4-butanediol diacrylate.

[0055] Example 3

[0056] The difference between Example 3 and Example 1 of this application is that the phosphonyl undecylenyl propionate in Example 1 is replaced by 4-hydroxybutyl acrylate.

[0057] Example 4

[0058] The difference between Example 4 and Example 1 of this application is that the N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 3-[tris(1-methylethoxy) silyl]propyl methacrylate.

[0059] Example 5

[0060] The difference between Example 5 and Example 1 of this application is that the N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 3-[2-hydroxyethoxy(dimethoxy)silyl]propyl 2-methyl-2-propenoate.

[0061] Comparative Example 1

[0062] The difference between Comparative Example 1 and Example 1 of this application is that the phosphonyl undecylenyl propionate in Example 1 is replaced by polybutyl acrylate.

[0063] Comparative Example 2

[0064] The difference between Comparative Example 2 and Example 1 of this application is that the N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 3-(methacryloyloxy)propyltrimethoxysilane.

[0065] Comparative Example 3

[0066] A preparation method of an environment-friendly multifunctional PVB film includes the following steps:

[0067] Mix 100 kg of PVB resin, 12 kg of dioctyl adipate, 2 kg of antioxidant 1076, and 20 kg of etched hollow glass microspheres evenly, stir at 3000 rpm for 20 min, plasticize at 165 °C, and form a film through a mold to prepare an environment-friendly multifunctional PVB film.

[0068] The preparation method of the etched hollow glass microspheres includes the following steps:

[0069] 4 kg of sodium hydroxide and 100 L of water were stirred at 200 rpm for 10 min, then 10 kg of hollow glass microspheres were added, and the mixture was stirred and refluxed at 80 °C for 6 h, then left to stand for 2 h. The upper-layer hollow glass microspheres were taken for suction filtration and then washed with water until the pH reached 7, and then dried at 100 °C for 12 h to obtain etched hollow glass microspheres.

[0070] Test Example 1

[0071] Limiting oxygen index: Tested in accordance with GB / T 2406.2-2009, and the test results are shown in Table 1:

[0072]

[0073] Test Example 2

[0074] Tensile strength was determined in accordance with GB / T 1040.3-2006 "Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets", with a tensile rate of 5 mm / min;

[0075] Flexural strength was determined in accordance with GB / T 9341-2008 "Plastics - Determination of flexural properties", with an experimental rate of 2 mm / min, and the test results are shown in Table 2:

[0076]

[0077] From the test data results in Table 1 and Table 2 of Examples 1-5 and Comparative Examples 1-3, it can be found that the flame retardancy and mechanical properties of the environmentally friendly multifunctional PVB film prepared in Example 1 are the best.

[0078] Comparing the tabular data in Examples 1-3 and Comparative Example 1, it was found that the environmentally friendly multifunctional PVB film prepared in Example 1 had better flame retardancy and mechanical properties. The possible reason was the use of different sizing agents. The sizing agent could coat the surface of etched hollow glass microspheres through a physical infiltration mode, improve the surface polarity of the material, and enhance the wettability and bonding strength between the PVB polymer and the modified hollow glass microspheres. At the same time, the sizing agent could also form covalent bonds with the active groups of the etched hollow glass microspheres and the PVB polymer through chemical cross-linking, playing a "bridging role". However, the sizing agent in Example 1 contained not only carboxyl functional groups and double bonds but also phosphate groups. In addition to being able to embed into the honeycomb-like porous structure of the hollow glass microspheres modified by the modifier for coating, these functional groups could also chemically cross-link with the hollow glass microspheres modified by the modifier to form a new interface. And the phosphate groups would be converted into phosphoric acid during the combustion process and further dehydrate and polymerize to form polyphosphoric acid. Polyphosphoric acid was a glassy melt that could form a stable covering layer on the surface of the polymer. This covering layer could prevent the approach of oxygen and at the same time reduce the release of volatile pyrolysis products, thus playing a flame retardant role. In addition, this covering layer could also insulate heat, reduce the temperature inside the polymer, and further slow down the combustion rate. Since the sizing agents in Examples 2-3 and Comparative Example 1 did not contain phosphate groups, when encountering flame combustion, the PVB film could not produce polyphosphoric acid to retard the flame. Therefore, in terms of flame retardancy effect, the effects of Examples 2-3 and Comparative Example 1 were worse.

[0079] Comparing the test data in the tables of Example 1, Examples 4 - 5 and Comparative Example 2, it is found that the flame retardant performance in Example 1 is the best. The reason for these differences lies in the use of a modifier. The modifier contains a siloxane group, which can react with the hydroxyl groups on the surface of the etched hollow glass microspheres, causing the binding mode between PVB and the modified hollow glass microspheres to change from mostly physical coating to mostly chemical bonding, thus firmly binding the silane coupling agent to the surface of the microspheres. In addition to containing hydrolyzable groups such as alkoxy groups, the modifier in Example 1 may contain organic functional groups such as amino groups and methacryloxy groups, which can undergo chemical reactions with the PVB resin, sizing agent, etched hollow glass microspheres, etc., thereby improving the interfacial interaction between them. This chemical bonding and interfacial enhancement effect helps the modified hollow glass microspheres to be more uniformly dispersed in the PVB resin, thus improving the overall flame retardant performance of the PVB film to a certain extent. Since the modifiers in Examples 4 - 5 and Comparative Example 2 may not have amino functional groups, and the amino functional groups can further crosslink with the hydroxyl groups on the surface of the etched hollow glass microspheres, increasing the crosslinking degree between the modifier and the etched hollow glass microspheres, the fluidity of the modified hollow glass microspheres in the PVB film is worse. However, the fluidity of the hollow glass microspheres helps to reduce the agglomeration of other materials and makes them more evenly distributed in the PVB film. The modified hollow glass microspheres in Examples 4 - 5 and Comparative Example 2 are not evenly distributed in the PVB film, so their flame retardant performance is also worse.

[0080] Comparing Example 1 and Comparative Example 3, it can be found that the flame retardant performance and mechanical strength of Example 1 are better. The possible reason is that the sizing agent fills the air interface part, improving the binding property between the modified hollow glass microspheres and PVB, reducing the air part inside the prepared PVB film, so the density increases slightly, and thus better mechanical properties are exhibited. At the same time, by surface coating the modified hollow glass microspheres, the surface morphology, crystal state and polarity of the hollow glass microspheres can be changed, thereby improving the compatibility between the hollow glass microspheres as fillers and the PVB resin matrix. The improvement of compatibility helps to reduce interfacial defects and enhance the binding force between the hollow glass microspheres and the PVB resin, thus improving the tensile strength of the PVB film. Therefore, the mechanical properties of the PVB film in Example 1 are better.

Claims

1. An environmentally friendly multifunctional PVB film, characterized in that: The invention comprises the following components by weight: 80-120 parts of PVB resin, 10-25 parts of plasticizer, 1-5 parts of antioxidant, and 10-30 parts of modified hollow glass microspheres; The preparation method of the modified hollow glass microspheres comprises the following steps, measured in parts by weight: S1. Add 1-8 parts of a modifier to 100-400 parts of water, stir at 200-500 rpm for 10-30 min, add 10-50 parts of alkali-etched hollow glass microspheres, stir at room temperature for 1-3 h to obtain a uniform mixture; S2, adding 1-8 parts of sizing agent to the uniform mixture, stirring at room temperature for 1-3 hours, and then filtering the mixture, drying, and cooling to room temperature to obtain modified hollow glass microspheres; The sizing agent is any one of 1,4-butanediol diacrylate, 4-hydroxybutyl acrylate and phosphoryl undecyl acrylate; The modifier is any one of 3-[tri(1-methylethoxy)silyl]propyl methacrylate, 2-methyl-2-acrylate-3-[2-hydroxyethoxy(dimethoxy)silyl]propyl ester and nitrogen-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane.

2. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: The sizing agent is phosphoryl undecyl propionate.

3. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: The plasticizer is one or more of trimellitic acid esters, adipate esters, maleic acid esters, benzoic acid esters and phosphate esters.

4. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1076, antioxidant 168, and antioxidant 264.

5. The method for preparing an environmentally friendly multifunctional PVB film according to any one of claims 1 to 4, characterized in that: The method comprises the following steps, in parts by weight: 80-120 parts of PVB resin, 10-25 parts of plasticizer, 1-5 parts of antioxidant and 10-30 parts of modified hollow glass microspheres are uniformly mixed, plasticized at 150-175° C., and formed into a film through a mold to prepare an environmentally friendly multifunctional PVB film.

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