Environment-friendly multifunctional PVB (polyvinyl butyral) film and preparation method thereof

Abstract

The invention discloses an environment-friendly multifunctional PVB (polyvinyl butyral) film and a preparation method thereof. The PVB film comprises PVB resin, a plasticizer, an antioxidant and modified hollow glass beads. According to the preparation method, the etched hollow glass beads are modified through the modifier, and then the sizing agent is embedded into the honeycomb porous structure to achieve physical and chemical coating effects, so that a new interface layer is formed. And finally, carrying out melt blending on the modified hollow glass beads to prepare the PVB film. Compared with the prior art, the environment-friendly multifunctional PVB film prepared by the invention has good flame retardant property.

Description

Technical Field

[0001] The present invention relates to the technical field of functional film materials, and in particular 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 the modification methods of polyvinyl alcohol in order to obtain new materials with better performance. Through the acetalization reaction, PVB film came into being. It not only retains the original advantages of polyvinyl alcohol, such as good hydrophilicity and film-forming properties, but also obtains higher heat resistance, weather resistance and impact resistance. The combination of these characteristics has enabled PVB film to quickly find its place in many fields such as construction, automobiles, electronics, and optics. Through the acetalization reaction, PVB film came into being. It not only retains the original advantages of polyvinyl alcohol, such as good hydrophilicity and film-forming properties, but also obtains higher heat resistance, weather resistance and impact resistance. The combination of these characteristics has enabled PVB film to quickly find its place in many fields such as construction, automobiles, electronics, and optics.

[0003] In the field of construction, PVB film is used as an interlayer material for 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 forces, even if it breaks, the fragments will be tightly adhered by the PVB film and will not splash 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 automobile windshields and side windows. It not only provides excellent impact resistance, but also effectively blocks ultraviolet rays and protects 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 car.

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

[0006] With the advancement of science and technology and the enhancement of environmental awareness, the application areas of PVB film are still expanding. In the field of new energy, PVB film is used as a packaging material for solar panels. Its excellent weather resistance and adhesion ensure the long-term stability and service life of the panels. In terms of environmentally friendly materials, scientists are also actively exploring the preparation technology of degradable PVB film in order to achieve the recycling of materials and reduce pollution to the environment.

[0007] CN114437482A discloses a special material for PVB film, a preparation method and application thereof, comprising the following components in parts by weight: polyvinyl butyral, hydrophobic amorphous nano-silicon dioxide, and a plasticizer. The invention makes the fumed silica hydrophobic by blending maleic anhydride-styrene alternating copolymer microspheres and fumed silica, and evenly disperses the fumed silica in a polymer matrix. The special material for PVB film prepared by the method has better weather resistance, moisture resistance and thermal insulation performance, and is widely used in photovoltaic thin-film solar cell modules, laminated glass, intermediate films, adhesives, etc. However, the thermal stability of the PVB film prepared by the method is poor.

[0008] CN118240318B discloses a high-strength heat-insulating PVB film and a preparation method thereof, wherein modified and reinforced aerogel, PVB resin, plasticizer and antioxidant are uniformly mixed and added to a twin-screw extruder for granulation. The invention uses modified and reinforced aerogel to heat-insulate and reinforce the PVB film, and at the same time, the mechanical properties are also improved to a certain extent; the modified and reinforced aerogel uses cellulose fibrils as raw materials, and as the fibrillation degree of the cellulose fibrils increases, more hydroxyl groups are exposed, and tight hydrogen bonds are formed between the fibrils, forming the stability of the network structure, and the formed aerogel has a high internal porosity, so that the air inside the aerogel is close to the inner wall of the pores and is in a relatively static state. The air has a high thermal resistance, which is not conducive to heat conduction, so the thermal conductivity is low and has excellent heat-insulating properties. However, the PVB film prepared by this method is very easy to burn when a fire occurs, and there will be many safety hazards. 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 properties of the environmentally friendly multifunctional PVB film and reduce the potential safety hazards in the event of a fire.

[0010] Since hollow glass microspheres are spherical and have the smallest surface area under the same volume in nature, this basic characteristic makes them have many physical and chemical properties that are incomparable to lightweight fillers, such as high compressive strength, high melting point, and high resistivity. Due to its unique hollow structure, it has properties such as light weight and sound insulation, and is known as a new era space material. In order to improve the performance of PVB materials, reduce costs, and meet specific application requirements, hollow glass microspheres are added to PVB films. However, when hollow glass microspheres are mixed into PVB resin, the compatibility of the two is poor, and there will be obvious poor interfaces after curing, so 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. The modified hollow glass microspheres are then blended with the PVB film, which is beneficial to improving the mechanical properties and thermal stability of the PVB film, while also increasing 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 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, wherein the modified hollow glass microspheres are prepared from etched hollow glass microspheres, a sizing agent, and a modifier.

[0013] Preferably, the method for preparing the modified hollow glass microspheres comprises the following steps: S1. Add the modifier to water, stir at 200-500 rpm for 10-30 min, add the etched hollow glass microspheres, stir at room temperature for 1-3 h to obtain a uniform mixture; S2. Add sizing agent to the uniform mixture, stir evenly at room temperature for 1-3 hours, filter, dry, and cool to room temperature to obtain modified hollow glass microspheres.

[0014] More preferably, the method for preparing the modified hollow glass microspheres comprises the following steps, 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 etched hollow glass microspheres, stir at room temperature for 1-3 h to obtain a uniform mixture; S2. Add 1-8 parts of sizing agent to the uniform mixture, stir at room temperature for 1-3 hours, then filter the mixture, dry it, and cool it to room temperature to obtain modified hollow glass microspheres.

[0015] Preferably, the sizing agent is any one of 1,4-butanediol diacrylate, 4-hydroxybutyl acrylate and phosphoryl undecylene propionate.

[0016] More preferably, the sizing agent is phosphoryl undecyl propionate.

[0017] Preferably, 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.

[0018] Preferably, the plasticizer is one or more of trimellitic acid esters, adipate esters, maleic acid esters, benzoic acid esters, and phosphate esters.

[0019] Preferably, the antioxidant is one or more of antioxidant 1076, antioxidant 168, and antioxidant 264.

[0020] The invention also discloses a method for preparing an environmentally friendly multifunctional PVB film.

[0021] A method for preparing an environmentally friendly multifunctional PVB film comprises the following steps, measured 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.

[0022] In this recipe, the ingredients and their functions are as follows: As the main component of the film, PVB resin provides the basic physical properties and structural integrity of the film, such as good toughness, adhesion and transparency.

[0023] Plasticizers mainly play the role of regulating and improving the flexibility and processing properties of environmentally friendly multifunctional PVB films.

[0024] Antioxidants mainly play the role of protecting the environmentally friendly multifunctional PVB film from oxidative degradation.

[0025] The hollow glass beads are etched to make their surface rough, which increases the interfacial bonding force between them and the PVB resin matrix, allowing the beads to be more effectively dispersed and firmly embedded in the membrane material, thereby significantly improving the tensile strength, toughness and wear resistance of the membrane. At the same time, the cavity structure inside the hollow glass beads gives the membrane material good thermal insulation and sound insulation properties. The hydroxyl content on the surface of the etched hollow glass beads increases, which is conducive to reacting with the modifier to form a covalent bond.

[0026] The modifier contains silane and double bonds. By introducing the modifier, functional groups or side chains that interact with the PVB resin molecular chain 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 improves the tensile strength and toughness of the film material.

[0027] 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, and 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, play a "bridging role", and form a strong chemical bond or physical adsorption layer. This coating not only improves the roughness of the microsphere surface, increases its contact area and interaction force with the PVB resin, but also promotes the fusion of the microspheres and the resin matrix in the subsequent plasticization process, thereby significantly improving the mechanical properties, heat resistance and weather resistance of the environmentally friendly multifunctional PVB film.

[0028] Beneficial effects of the present invention: Compared with the prior art, the etched hollow glass microspheres are modified by a modifier containing double bonds and silane, and then embedded into a honeycomb porous structure using a sizing agent 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 of the modified hollow glass microspheres with the PVB resin. DETAILED DESCRIPTION

[0029] Parameters for specific chemical substances used, sources.

[0030] 11-Phosphonoundecyl acrylate, CAS No.: 915376-49-7.

[0031] 2-methyl-2-propenoic acid 3-[2-hydroxyethoxy(dimethoxy)silyl]propyl ester, CAS No.: 29888-36-6.

[0032] N-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, [2-hydroxy-3-(3-triethoxysilylpropylamino)propyl] 2-methylprop-2-enoate, CAS number: 96132-98-8.

[0033] PVB resin, product number: P29692-100g, MW170,000-250,000, brand: Acmec, Shanghai Jizhi Biochemical Technology Co., Ltd.

[0034] Antioxidant 1076, BASF.

[0035] Hollow glass microspheres, thermal conductivity: 0.028-0.070 (W / m·K), impurities ≤0.04%, compressive strength: 1.5-123Mpa, porosity: 0.03%, refractory temperature: 630℃, Mohs hardness: 7.0, Hebei Houkang Mineral Products Co., Ltd.

[0036] Polybutyl acrylate, product number: DH05286, Hubei Dahao Chemical Co., Ltd.

[0037] Example 1 A method for preparing an environmentally friendly multifunctional PVB film comprises the following steps: 100 kg of PVB resin, 12 kg of dioctyl adipate, 2 kg of antioxidant 1076, and 20 kg of modified hollow glass microspheres were mixed evenly, stirred at 3000 rpm for 20 min, plasticized at 165° C., and formed into a film through a mold to prepare an environmentally friendly multifunctional PVB film.

[0038] The method for preparing the modified hollow glass microspheres comprises the following steps: S1. Add 4 kg of nitrogen-(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, stir at 25 ° C for 2 h to obtain a uniform mixture; S2. Add 5 kg of phosphoryl undecyl propionate to the uniform mixture, stir at 25° C. for 2 h, filter with suction for 8 min, bake at 80° C. for 12 h, and cool to 25° C. to obtain modified hollow glass microspheres.

[0039] The method for preparing the etched hollow glass microspheres comprises the following steps: 4 kg of sodium hydroxide and 100 L of water were stirred at 200 rpm for 10 min, and then 10 kg of hollow glass microspheres were added, and the mixture was stirred and refluxed at 80 ° C for 6 h, and then allowed to stand for 2 h. The upper layer of hollow glass microspheres was filtered and washed with water until the pH was 7, and then dried at 100 ° C for 12 h to obtain etched hollow glass microspheres.

[0040] Example 2 The difference between Example 2 of the present application and Example 1 is that the phosphoryl undecyl propionate in Example 1 is replaced by 1,4-butanediol diacrylate.

[0041] Example 3 The difference between Example 3 of the present application and Example 1 is that the phosphoryl undecylenic ester in Example 1 is replaced by 4-hydroxybutyl acrylate.

[0042] Example 4 The difference between Example 4 of the present application and Example 1 is that the nitrogen-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 3-[tri(1-methylethoxy)silyl]propyl methacrylate.

[0043] Example 5 The difference between Example 5 of the present application and Example 1 is that the nitrogen-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 2-methyl-2-acrylic acid-3-[2-hydroxyethoxy(dimethoxy)silyl]propyl ester.

[0044] Comparative Example 1 The difference between Comparative Example 1 of the present application and Example 1 is that the phosphoryl undecylylate in Example 1 is replaced by polybutyl acrylate.

[0045] Comparative Example 2 The difference between Comparative Example 2 of the present application and Example 1 is that the nitrogen-(3-methacryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane in Example 1 is replaced by 3-(isomethacryloyloxy)propyltrimethoxysilane.

[0046] Comparative Example 3 A method for preparing an environmentally friendly multifunctional PVB film comprises the following steps: 100 kg of PVB resin, 12 kg of dioctyl adipate, 2 kg of antioxidant 1076, and 20 kg of etched hollow glass microspheres were mixed evenly, stirred at 3000 rpm for 20 min, plasticized at 165° C., and formed into a film through a mold to prepare an environmentally friendly multifunctional PVB film.

[0047] The method for preparing the etched hollow glass microspheres comprises the following steps: 4 kg of sodium hydroxide and 100 L of water were stirred at 200 rpm for 10 min, and then 10 kg of hollow glass microspheres were added, and the mixture was stirred and refluxed at 80 ° C for 6 h, and then allowed to stand for 2 h. The upper layer of hollow glass microspheres was filtered and washed with water until the pH was 7, and then dried at 100 ° C for 12 h to obtain etched hollow glass microspheres. Test Example 1

[0048] Limiting oxygen index: Tested in accordance with GB / T 2406.2-2009, the test results are shown in Table 1:

[0049] Test Example 2

[0050] The tensile strength is measured according to GB / T 1040.3-2006 "Determination of tensile properties of plastics Part 3: Test conditions for films and sheets", with a tensile rate of 5 mm / min; The bending strength is measured according to GB / T 9341-2008 "Determination of Flexural Properties of Plastics", the test rate is 2mm / min, the test results are shown in Table 2:

[0051] Through 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 retardant property and mechanical property of the environmentally friendly multifunctional PVB film prepared in Example 1 are the best.

[0052] Comparing the tabular data in Examples 1-3 and Comparative Example 1, it is found that the flame retardant and mechanical properties of the environmentally friendly multifunctional PVB film prepared in Example 1 are good, and the possible reason is that different sizing agents are used. The sizing agent can be coated on the surface of the etched hollow glass microspheres by the mode of physical infiltration, improve the surface polarity of the material, and enhance the wettability and bonding strength of the PVB polymer and the modified hollow glass microspheres. At the same time, the sizing agent can also form a covalent bond with the active groups of the etched hollow glass microspheres and the PVB polymer by chemical crosslinking, playing a "bridging role". However, the sizing agent in Example 1 contains a phosphate group in addition to a carboxyl functional group and a double bond. In addition to being embedded in the honeycomb porous structure of the hollow glass microspheres modified by the modifier for coating, these functional groups can be chemically crosslinked with the hollow glass microspheres modified by the modifier to form a new interface. And the phosphate group will be converted into phosphoric acid during the combustion process, and further dehydrated and polymerized to form polyphosphoric acid. Polyphosphoric acid is a glassy melt that can form a stable covering layer on the polymer surface. This covering layer can prevent oxygen from approaching and reduce the release of volatile pyrolysis products, thereby playing a flame retardant role. In addition, this covering layer can also isolate heat, reduce the temperature inside the polymer, and further slow down the combustion rate. Because the sizing agents in Examples 2-3 and Comparative Example 1 do not contain phosphoric acid groups, the PVB film cannot produce polyphosphoric acid to flame retardant when encountering flame combustion, so in terms of flame retardant effect, the effects of Examples 2-3 and Comparative Example 1 are worse.

[0053] Compared with the test data in the table 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 is the use of a modifier. The modifier contains a siloxy group, which can react with the hydroxyl group on the surface of the etched hollow glass microspheres, so that the bonding mode of PVB and the modified hollow glass microspheres is changed from most physical coating to most chemical bonding, thereby firmly bonding 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 amino, methacryloyloxy and other organic functional groups that react chemically with PVB resin or sizing agent, etched hollow glass microspheres, etc., thereby improving the interface between the two. This chemical bonding and interface enhancement effect helps the modified hollow glass microspheres to be more evenly dispersed in the PVB resin, thereby 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 cross-link with the hydroxyl groups on the surface of the etched hollow glass microspheres, the degree of cross-linking between the modifier and the etched hollow glass microspheres is increased, so that 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 make them more evenly distributed in the PVB film. The modified hollow glass microspheres in Examples 4-5 and Comparative Example 2 are unevenly distributed in the PVB film, so the flame retardant properties will also be worse.

[0054] Compared with Example 1 and Comparative Example 3, it can be found that the flame retardant properties and mechanical strength of Example 1 are better. The possible reason is that the sizing agent fills the air interface part, the bonding of the modified hollow glass microspheres and PVB is improved, so that the air part inside the prepared PVB film is reduced, so the density is slightly increased, and then better mechanical properties are shown. At the same time, the surface morphology, crystallinity and polarity of the hollow glass microspheres can be changed by surface coating the modified hollow glass microspheres, thereby improving the compatibility between the hollow glass microspheres as fillers and the PVB resin matrix. The improvement of compatibility helps to reduce interface defects and enhance the bonding force between the hollow glass microspheres and the PVB resin, thereby improving the tensile strength of the PVB film, so 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 modified hollow glass microspheres are prepared by etching hollow glass microspheres, sizing agent and modifier.

2. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: The preparation method of the modified hollow glass microspheres comprises the following steps: S1. Add the modifier to water, stir at 200-500 rpm for 10-30 min, add the etched hollow glass microspheres, stir at room temperature for 1-3 h to obtain a uniform mixture; S2. Add sizing agent to the uniform mixture, stir at room temperature for 1-3 hours, filter, dry, and cool to room temperature to obtain modified hollow glass microspheres.

3. The environmentally friendly multifunctional PVB film according to claim 2, characterized in that: 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 etched hollow glass microspheres, stir at room temperature for 1-3 h to obtain a uniform mixture; S2. Add 1-8 parts of sizing agent to the uniform mixture, stir at room temperature for 1-3 hours, then filter the mixture, dry it, and cool it to room temperature to obtain modified hollow glass microspheres.

4. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: The sizing agent is any one of 1,4-butanediol diacrylate, 4-hydroxybutyl acrylate and phosphoryl undecylene acrylate.

5. The environmentally friendly multifunctional PVB film according to claim 4, characterized in that: The sizing agent is phosphoryl undecyl propionate.

6. The environmentally friendly multifunctional PVB film according to claim 1, characterized in that: 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.

7. 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.

8. 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.

9. The method for preparing an environmentally friendly multifunctional PVB film according to any one of claims 1 to 7, 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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