Flame-retardant heat-insulating film material and preparation method thereof

Abstract

The invention discloses a flame-retardant heat-insulating film material and a preparation method thereof, and belongs to the technical field of film materials. Comprising the following raw materials in parts by weight: 83-95 parts of PET resin, 11-17 parts of boron nitride, 4-12 parts of a modifier, 4-6 parts of a coupling agent and 3-6 parts of an additive. Boron nitride is added into the film material, and the film material is endowed with heat insulation performance by utilizing the unique layered structure and high heat conductivity of the boron nitride, so that the requirement of the automobile window film on heat insulation is met; the modifier prepared by a two-step method is combined with a plurality of functional groups, so that the synergistic improvement of flame retardance, heat insulation and impact resistance is realized; the modifier is prepared from conventional chemical reagents, the reaction principle is simple, and industrial production is easy; in conclusion, the prepared flame-retardant and heat-insulating film material has heat-insulating, flame-retardant and impact-resistant properties, the problems that a traditional polyester film is insufficient in impact resistance and flame-retardant property and the like are solved, the requirements of the field of automobile window films for high-performance materials are met, and the flame-retardant and heat-insulating film material has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of membrane materials. Specifically, it relates to a flame-retardant and heat-insulating membrane material and a preparation method thereof. Background Art

[0002] With the rapid development of the automotive industry and the continuous improvement of people's requirements for automotive comfort and safety, automotive window film materials have received increasing attention. Window film materials are functional films widely applied to the surface of automotive glass, and their main functions include heat insulation, ultraviolet protection, privacy protection, and safety improvement, etc.

[0003] Traditional window film materials usually use polyester (PET) film as the base material, and a metal layer, ceramic particles, or other functional coatings are coated on its surface. This kind of coating can effectively block infrared rays and ultraviolet rays in sunlight, thereby reducing the temperature inside the vehicle and reducing the energy consumption of the air-conditioning system. For example, a metal-coated window film can achieve a heat-insulating effect by reflecting infrared rays, but this kind of coating has poor scratch resistance and is easy to fall off, and it is prone to oxidation after long-term use, resulting in color change or performance degradation of the film layer.

[0004] In addition to heat-insulating performance, the flame-retardant performance of window films has also gradually received attention. Especially in the context of the rapid development of new energy vehicles, the safety of vehicles has been raised to an unprecedented height. Once a fire occurs, if the window film can have certain flame-retardant characteristics, it can delay the spread speed of the flame and buy more escape time for passengers. However, the traditional polyester film has poor flame-retardant performance. Once encountering a fire hazard, the heat-insulating film will first burn immediately, causing heavy losses to people's lives and property, which greatly limits the application of the heat-insulating film.

[0005] Finally, the window film also needs to have certain impact resistance to improve the safety of the vehicle. When a vehicle collides, the window glass is easy to break and cause secondary injuries to passengers. High-quality window films can play a bonding role when the glass breaks, preventing fragments from splashing, thereby protecting the safety of passengers. To sum up, there is an urgent need to invent a membrane material with heat insulation, flame retardancy, and impact resistance to meet the higher application requirements in the field of automotive window films. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a flame-retardant and heat-insulating membrane material and a preparation method thereof.

[0007] The purpose of the present invention can be achieved by the following technical solutions: A preparation method of a flame-retardant and heat-insulating membrane material, comprising the following steps: Fully dry the PET resin, then mix it thoroughly with boron nitride, modifier, coupling agent and additive, add it to a twin-screw extruder, and then carry out co-mixing extrusion by the twin-screw extruder, cast it onto a cooling roller, form a film through cooling and shaping, and wind it up to obtain a flame-retardant and heat-insulating film material.

[0008] Further, the raw materials are as follows by mass parts: 83-95 parts of PET resin, 11-17 parts of boron nitride, 4-12 parts of modifier, 4-6 parts of coupling agent, 3-6 parts of additive.

[0009] Further, the additive is composed of an antioxidant and a lubricant in a mass ratio of 2:1.

[0010] Furthermore, the antioxidant is a phosphite antioxidant.

[0011] Furthermore, the lubricant is one of epoxy soybean oil, butyl stearate and stearic acid.

[0012] Boron nitride is an inorganic material with a unique layered structure. This structure has significant anisotropy at the microscale, and this structural feature strongly interferes with the propagation path of infrared light. Moreover, boron nitride has an extremely high thermal conductivity. When infrared light irradiates the surface of the boron nitride material, part of the light energy will be converted into heat energy. Therefore, the addition of boron nitride can improve the heat-insulating performance of the film material.

[0013] Further, the modifier is prepared through the following steps: Step A1: Assemble a three-necked flask and a stirring device, displace the air with nitrogen, weigh 4,4'-dichlorodiphenyl sulfone and stearylamine as reaction raw materials, and sequentially add them to the flask together with the solvent N,N-dimethylformamide. After stirring and mixing, add potassium carbonate, and heat the device until the temperature reaches 60 °C. At this temperature, keep the reaction for 5 h. After the reaction is completed, filter, rotary evaporate to remove part of the solvent, and then purify by column chromatography to obtain Product 1; Further, in Step A1, the dosage ratio of 4,4'-dichlorodiphenyl sulfone, stearylamine, N,N-dimethylformamide, and potassium carbonate is 29.2 g:26.9 g:100 mL:13.8 g.

[0014] The reaction principle of Step A1 is: Under the catalysis of potassium carbonate, 4,4'-dichlorodiphenyl sulfone and stearylamine undergo a nucleophilic substitution reaction, and precisely control the dosage of the two to reduce the occurrence of side reactions; the reaction formula is as follows:

[0015] Step A2: Assemble a three-necked flask, a dropping funnel and a stirring device, purge with nitrogen to displace air. Weigh product 1 and 4-hydroxybenzeneboronic acid as reaction raw materials, and successively add them to the flask with anhydrous toluene as the solvent. At room temperature, under stirring, slowly add sodium hydroxide solution (mass fraction 20%) through a constant-pressure dropping funnel. After the addition is complete, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir the reaction for 6 h. After the reaction is completed, let it stand for liquid separation, wash 3 times with deionized water, dry the organic phase with anhydrous sodium sulfate, filter, rotary evaporate under reduced pressure to remove part of the solvent, and then purify by column chromatography to obtain the modifier; Further, in step A2, the dosage ratio of product 1, 4-hydroxybenzeneboronic acid, anhydrous toluene, and sodium hydroxide solution is 13.8 g: 51.9 g: 150 mL: 20 mL.

[0016] The reaction principle of step A2 is that sodium hydroxide can react with the hydroxyl group in the 4-hydroxybenzeneboronic acid molecule to form a phenolate, and react with product 1; the reaction formula is as follows:

[0017] The modifier prepared by the present invention in two steps has a simple preparation principle, and the raw materials used are conventional chemical reagents. Sulfonyl group, boric acid, benzene ring and long carbon chain groups are introduced into the modifier. Among them, the S=O double bond of the sulfonyl group has a relatively high bond energy, and when it decomposes at high temperature, it will release incombustible gases. These gases can dilute the concentration of combustible gases and form a barrier in the combustion area to prevent oxygen from contacting the substrate, thereby inhibiting the combustion process; the introduced boric acid group will form a stable boroxine cross-linked network under high-temperature conditions. When the temperature continues to rise, this network structure is further transformed into a dense B-O-C thermally stable carbon layer. This carbon layer uniformly covers the surface of the material, forming an effective physical barrier, which can cooperate with the sulfonyl group to greatly improve the flame retardancy of the material; in addition to the two introduced flame retardant elements, the modifier also contains a benzene ring. The aromatic ring structure not only has high thermal stability and can form a stable carbon layer at high temperature, thereby inhibiting the combustion process and further enhancing the flame retardancy of the material. Finally, due to its long carbon chain structure, the long carbon chain group in the modifier molecule has high molecular chain flexibility and freedom. This flexibility enables the material to absorb energy through the rotation, slip or stretching of the molecular chain when subjected to external forces, thereby avoiding material cracking caused by stress concentration and improving the impact resistance of the material. Moreover, the long carbon chain can also penetrate into the macromolecular chains of the polymer to improve the migration resistance of the small molecule modifier.

[0018] The beneficial effects of the present invention: 1. By adding boron nitride to the membrane material, using its unique layered structure and high thermal conductivity, the membrane material is given a certain degree of heat insulation performance, meeting the heat insulation requirements of automotive window films; 2. The modifier prepared by the two-step method combines multiple functional groups (sulfone group, boric acid, benzene ring, long carbon chain), achieving a synergistic improvement in flame retardancy, heat insulation and impact resistance; 3. The preparation of the modifier uses conventional chemical reagents, and the reaction principle is simple, which is easy for industrial production; In summary, the flame-retardant and heat-insulating film material prepared by the present invention has heat insulation, flame retardancy and impact resistance, overcomes the problems such as insufficient impact resistance and flame retardancy of traditional polyester films, meets the requirements of the automotive window film field for high-performance materials, and has broad application prospects. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Example 1 Preparation of the modifier: Step A1: Assemble a three-necked flask and a stirring device, displace the air with nitrogen, weigh 29.2 g of 4,4'-dichlorodiphenyl sulfone and 26.9 g of stearylamine as reaction raw materials, and sequentially add 100 mL of the solvent N,N-dimethylformamide to the flask. After stirring and mixing, add 13.8 g of potassium carbonate, and heat the device until the temperature reaches 60 °C. At this temperature, keep the reaction for 5 h. After the reaction is completed, filter, rotary evaporate to remove part of the solvent, and then purify by column chromatography (the eluent is benzene and ethyl acetate, and the volume ratio of the two is 3:1). Rotary evaporate to remove the eluent to obtain Product 1; Step A2: Assemble a three-necked flask, a dropping funnel and a stirring device, displace the air with nitrogen, weigh 13.8 g of Product 1 and 51.9 g of 4-hydroxybenzeneboronic acid as reaction raw materials, and sequentially add 150 mL of the solvent anhydrous toluene to the flask. At room temperature, under stirring, slowly add 20 mL of sodium hydroxide solution (mass fraction 20%) through a constant-pressure dropping funnel. After the addition is completed, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir the reaction for 6 h. After the reaction is completed, let it stand for liquid separation, wash it 3 times with deionized water, dry the organic phase with anhydrous sodium sulfate, filter, and rotary evaporate under reduced pressure to remove part of the solvent, and then purify by column chromatography (the eluent is benzene and ethyl acetate, and the volume ratio of the two is 5:1). Rotary evaporate to remove the eluent to obtain the modifier.

[0021] Example 2 Preparation of the modifier: Step A1: Assemble a three-necked flask and a stirring device, purge with nitrogen to displace air. Weigh 58.4 g of 4,4'-dichlorodiphenyl sulfone and 53.8 g of stearylamine as reaction raw materials, and successively add them to the flask along with 400 mL of the solvent N,N-dimethylformamide. After stirring and mixing, add 27.6 g of potassium carbonate, and heat the device until the temperature reaches 60 °C. At this temperature, maintain the reaction for 5 h. After the reaction is completed, filter, rotary evaporate to remove some of the solvent, and then purify by column chromatography (the eluent is benzene and ethyl acetate, and their volume ratio is 3:1). Rotary evaporate to remove the eluent to obtain Product 1; Step A2: Assemble a three-necked flask, a dropping funnel and a stirring device, purge with nitrogen to displace air. Weigh 27.6 g of Product 1 and 103.8 g of 4-hydroxybenzeneboronic acid as reaction raw materials, and successively add them to the flask along with 300 mL of the solvent anhydrous toluene. At room temperature, while stirring, slowly add 40 mL of sodium hydroxide solution (mass fraction 20%) through a constant-pressure dropping funnel. After the addition is completed, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir the reaction for 6 h. After the reaction is completed, let it stand for liquid separation, wash 3 times with deionized water, dry the organic phase with anhydrous sodium sulfate, filter, and rotary evaporate under reduced pressure to remove some of the solvent. Then purify by column chromatography (the eluent is benzene and ethyl acetate, and their volume ratio is 5:1). Rotary evaporate to remove the eluent to obtain the modifier.

[0022] Example Three Fully dry 83 g of PET resin, then mix it thoroughly with 11 g of boron nitride, 4 g of the modifier prepared in Example One, 4 g of silane coupling agent KH-560, and 3 g of additives (composed of 2 g of antioxidant 168 and 1 g of epoxy soybean oil). Then add the mixture to a twin-screw extruder, and then carry out co-mixing and extrusion through the twin-screw extruder, cast it onto a cooling roller, form a film through cooling and shaping, and wind it up to obtain a flame-retardant and heat-insulating film material.

[0023] Example Four Fully dry 89 g of PET resin, then mix it thoroughly with 14 g of boron nitride, 8 g of the modifier prepared in Example Two, 5 g of silane coupling agent KH-560, and 6 g of additives (composed of 4 g of antioxidant 168 and 2 g of stearic acid). Then add the mixture to a twin-screw extruder, and then carry out co-mixing and extrusion through the twin-screw extruder, cast it onto a cooling roller, form a film through cooling and shaping, and wind it up to obtain a flame-retardant and heat-insulating film material.

[0024] Example Five 95 g of PET resin was fully dried, and then mixed thoroughly with 17 g of boron nitride, 12 g of the modifier prepared in Example 2, 6 g of silane coupling agent KH-560 and 6 g of additives (composed of 4 g of antioxidant 168 and 2 g of butyl stearate). Then, it was added to a twin-screw extruder and co-extruded through the twin-screw extruder, cast onto a cooling roll, formed into a film by cooling and shaping, and wound up to obtain a flame-retardant and heat-insulating film material.

[0025] Comparative Example 1 Different from Example 5, a commercially available toughening agent of the same mass was used to replace the modifier in Example 5 to obtain a material.

[0026] Comparative Example 2 Different from Example 5, a commercially available flame retardant of the same mass was used to replace the modifier in Example 5 to obtain a material.

[0027] Perform performance tests on Examples 3, 4, 5, and Comparative Examples 1 and 2: The measured results are shown in the following table: As can be seen from the above table, for the film materials prepared in the examples of the present invention, after the addition of the modifier, their flame retardancy and impact resistance are higher than those of the comparative examples. Therefore, the present invention has important application value in the technical field of film materials.

[0028] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0029] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar methods for substitution, which should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a flame-retardant and heat-insulating film material, characterized in that, It includes the following steps: Fully dry the PET resin, then mix it thoroughly with boron nitride, modifier, coupling agent and additive, add it to a twin-screw extruder, and then carry out co-mixing extrusion by the twin-screw extruder, cast it onto a cooling roll, form a film through cooling and shaping, and wind it up to obtain a flame-retardant and heat-insulating film material.

2. The preparation method of a flame-retardant and heat-insulating film material according to claim 1, characterized in that, The modifier is prepared through the following steps: Step A1: Add 4,4'-dichlorodiphenyl sulfone, stearylamine and N,N-dimethylformamide to a flask in sequence. After stirring and mixing, add potassium carbonate, and keep the reaction at 60 °C for 5 h. After the reaction is completed, obtain Product 1; Step A2: Add Product 1 and 4-hydroxyphenylboronic acid to a flask in sequence with anhydrous toluene. At room temperature, while stirring, dropwise add sodium hydroxide solution. After the dropping is completed, stir and react at 70 °C for 6 h. After the reaction is completed, obtain the modifier.

3. The preparation method of a flame-retardant and heat-insulating film material according to claim 2, characterized in that, In Step A1, the dosage ratio of 4,4'-dichlorodiphenyl sulfone, stearylamine, N,N-dimethylformamide, and potassium carbonate is 29.2 g: 26.9 g: 100 mL: 13.8 g.

4. The preparation method of a flame-retardant and heat-insulating film material according to claim 2, wherein In Step A1, the dosage ratio of Product 1, 4-hydroxyphenylboronic acid, anhydrous toluene, and sodium hydroxide solution is 13.8 g: 51.9 g: 150 mL: 20 mL.

5. The preparation method of a flame-retardant and heat-insulating film material according to claim 1, characterized in that, Each raw material is as follows by mass fraction: 83-95 parts of PET resin, 11-17 parts of boron nitride, 4-12 parts of modifier, 4-6 parts of coupling agent, 3-6 parts of additive.

6. The preparation method of a flame-retardant and heat-insulating film material according to claim 1, wherein, The additive is composed of an antioxidant and a lubricant in a mass ratio of 2:

1.

7. The preparation method of a flame-retardant and heat-insulating film material according to claim 6, characterized in that, The antioxidant is a phosphite antioxidant.

8. The preparation method of a flame retardant and heat insulation film material according to claim 6, characterized in that, The lubricant is one of epoxy soybean oil, butyl stearate and stearic acid.

9. A flame-retardant and heat-insulating film material, characterized in that, Prepared according to the method described in any one of Claims 1-8.

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