Flame-retardant insulating film

Abstract

This application provides a flame-retardant insulating film comprising polypropylene, a halogen-free foaming flame retardant, and a synergistic additive. The halogen-free foaming flame retardant accounts for 39% to 50% of the weight of the flame-retardant insulating film. The synergistic additive is a sheet-like inorganic material with a sheet diameter of 2 μm to 200 μm, and accounts for 0.5% to 6% of the weight of the flame-retardant insulating film.

Description

Technical Field

[0001] [Related Applications] This international application claims priority to Chinese Patent Application No. 202211348201.1, filed on October 31, 2022. The entire content of Chinese Patent Application No. 202211348201.1 is incorporated herein by reference.

[0002] This application relates to the field of films, particularly flame-retardant insulating films and electrical components including flame-retardant insulating films.

Background Art

[0003] Flame-retardant insulating films are used to insulate various types of electronic devices or components to avoid failures of electronic components between or within electronic devices and components due to short circuits, breakdowns, etc., and to reduce the risk of ignition of electronic devices or components, thereby ensuring the normal operation of various electronic components. Conventionally, insulating films are manufactured using halogenated flame retardants. However, halogenated flame retardants are harmful to the environment. In order to eliminate the environmental impact, attempts have been made to manufacture flame-retardant insulating films using halogen-free flame retardants.

Summary of the Invention

[0004] This application provides a flame-retardant insulating film, and the high-temperature-resistant insulating film is used in an electronic device or component to meet the requirements of insulation and flame retardancy for the electronic device or component.

[0005] In a first aspect, this application provides a flame-retardant insulating film comprising polypropylene, a halogen-free foaming flame retardant, and a synergistic additive. The halogen-free foaming flame retardant accounts for 39% to 50% of the weight of the flame-retardant insulating film. The synergistic additive is a sheet-like inorganic material with a sheet diameter of 2 μm to 200 μm, and the synergistic additive accounts for 0.5% to 6% of the weight of the flame-retardant insulating film.

[0006] In the flame-retardant insulating film described above, the sheet diameter of the sheet-like inorganic material is 4 μm to 80 μm.

[0007] In the flame-retardant insulating film described above, the sheet-like inorganic material includes at least one of mica and talc powder.

[0008] In the flame-retardant insulating film described above, the polypropylene is either linear homopolymer polypropylene or linear copolymer polypropylene, and the polypropylene accounts for 45% to 57% of the weight of the flame-retardant insulating film.

[0009] In the above-described flame-retardant insulating film, the halogen-free foaming flame retardant is selected from at least one of ammonium polyphosphate or its derivatives, melamine polyphosphate or its derivatives, and piperazine pyrophosphate or its derivatives.

[0010] In the above-mentioned flame-retardant insulating film, the halogen-free foaming flame retardant consists of ammonium polyphosphate or its derivative and melamine polyphosphate or its derivative, with ammonium polyphosphate or its derivative accounting for 17% to 35% of the weight of the flame-retardant insulating film, and melamine polyphosphate or its derivative accounting for 10% to 25% of the weight of the flame-retardant insulating film.

[0011] In the above-mentioned flame-retardant insulating film, the halogen-free foaming flame retardant consists of piperazine pyrophosphate or its derivative and melamine polyphosphate or its derivative, with piperazine pyrophosphate or its derivative accounting for 17% to 35% of the weight of the flame-retardant insulating film, and melamine polyphosphate or its derivative accounting for 10% to 25% of the weight of the flame-retardant insulating film.

[0012] The above flame-retardant insulating film further comprises a flame-retardant additive and a charring agent. The flame-retardant additive accounts for less than 15% of the weight of the flame-retardant insulating film and contains melamine cyanurate. The charring agent accounts for less than 2% of the weight of the flame-retardant insulating film and is selected from at least one of pentaerythritol and triazine.

[0013] The above flame-retardant insulating film further contains additional flame retardants, the additional flame retardants accounting for less than 5% of the weight of the flame-retardant insulating film, and the additional flame retardants include alkyl hypophosphite.

[0014] The flame-retardant insulating film described above has a thickness of 0.08 mm to 3 mm.

[0015] The flame-retardant insulating film described above is manufactured by a melt extrusion molding process.

[0016] In a second embodiment, the present invention provides an electrical device comprising a housing and electrical components disposed within the housing. The electrical components are enclosed or partially enclosed by a flame-retardant insulating film according to the present invention.

[0017] The electrical device mentioned above is a power adapter or power supply unit.

[0018] In a third embodiment, the present application provides a formulation of a flame-retardant insulating material comprising polypropylene, a halogen-free foaming flame retardant, and a synergistic additive. The halogen-free foaming flame retardant accounts for 39% to 50% of the weight of the flame-retardant insulating film. The synergistic additive is a sheet-like inorganic material with a sheet diameter of 2 μm to 200 μm, and accounts for 0.5% to 6% of the weight of the flame-retardant insulating film. [Brief explanation of the drawing]

[0019] [Figure 1A] This is a schematic diagram of the structure of an example electrical device including the flame-retardant insulating film of the present application. [Figure 1B]This is a schematic diagram of the structure of an example electrical device including the flame-retardant insulating film of the present application. [Modes for carrying out the invention]

[0020] Various specific embodiments of the present application are described below with reference to the accompanying drawings which constitute part of this specification. While terms indicating orientation, such as “front,” “rear,” “top,” “bottom,” “left,” “right,” “top,” “bottom,” “inside,” and “outside,” are used in this application to describe various exemplary structural components and elements, it should be understood that these terms are used solely for illustrative purposes and are determined based on the exemplary orientations shown in the accompanying drawings. Since the examples disclosed herein can be arranged in different orientations, these terms indicating orientation are for illustrative purposes only and should not be considered limiting.

[0021] In this application, unless otherwise specified, all equipment and materials may be purchased from the market or are commonly used in the industry. The methods in the following examples are conventional methods in the art unless otherwise specified.

[0022] Polypropylene film materials are commonly used plastic materials that possess excellent mechanical, processing, and molding properties, and are relatively inexpensive. They are widely used, for example, as insulating films in the electrical field. However, the flame retardancy of polypropylene film material itself is low, and it is often necessary to improve the flame retardancy of the polypropylene film material by compounding it with a flame retardant to obtain a flame-retardant insulating film. The inventors of this application have found that the flame retardancy of a flame-retardant insulating film is related to the thickness of the film and the amount of flame retardant added. Generally, the thicker the flame-retardant insulating film, the better the flame retardant effect. However, thick flame-retardant insulating films cannot meet the development requirements for lightweighting and miniaturizing electrical components such as power adapters and batteries. To meet the development requirements for lightweighting and miniaturizing electrical components such as power adapters and batteries, it is desirable to manufacture thinner flame-retardant insulating films.

[0023] The inventors of this invention have found that the flame retardant performance of a flame-retardant insulating film can be improved by increasing the amount of flame retardant added to the film. However, the inventors have also found that increasing the amount of flame retardant can lead to a decrease in the mechanical and processing performance of the flame-retardant insulating film, potentially resulting in an uneven surface. Furthermore, halogen-free flame retardants are used to eliminate the environmental impact of flame retardants. However, halogen-free flame retardants are costly, so increasing the amount of halogen-free flame retardant used may lead to an increase in manufacturing costs.

[0024] The halogen-free flame retardant used in the flame-retardant insulating film of the present application is a halogen-free foaming flame retardant. The inventors of the present application have found that by using a small amount of sheet-like inorganic material as a synergistic additive in the flame-retardant insulating film, a synergistic effect with the halogen-free foaming flame retardant can be obtained, and it is possible to ensure that the flame-retardant insulating film has good flame-retardant performance without the need to thicken the flame-retardant insulating film or increase the amount of the halogen-free foaming flame retardant. Therefore, the present application can provide a flame-retardant insulating film that is environmentally friendly, thin, and has good flame-retardant performance while using a small amount of flame retardant.

[0025] The flame-retardant insulating film of the present application contains polypropylene, and its weight accounts for 45% to 57% of the weight of the flame-retardant insulating film. In some examples, the weight of polypropylene accounts for 47% to 55% of the weight of the flame-retardant insulating film. In some examples, polypropylene is linear homopolymer polypropylene or linear copolymer polypropylene.

[0026] The flame-retardant insulating film of this application further contains a halogen-free foaming flame retardant, the weight of which accounts for 39% to 50% of the weight of the flame-retardant insulating film. In some examples, the weight of the halogen-free foaming flame retardant accounts for 40% to 47% of the weight of the flame-retardant insulating film. The halogen-free foaming flame retardant is selected from at least one of ammonium polyphosphate (APP) or its derivatives, melamine polyphosphate (MPP) or its derivatives, and piperazine pyrophosphate (PAPP) or its derivatives. In some examples, the halogen-free foaming flame retardant consists of APP or its derivatives and MPP or its derivatives, the weight of APP or its derivatives accounts for 17% to 35% or 18% to 30% of the weight of the flame-retardant insulating film, and the weight of MPP or its derivatives accounts for 10% to 25% or 10% to 20% of the weight of the flame-retardant insulating film. In some other examples, the halogen-free foaming flame retardant consists of PAPP or its derivatives and MPP or its derivatives, where the weight of PAPP or its derivatives accounts for 17% to 35% or 18% to 30% of the weight of the flame-retardant insulating film, and the weight of MPP or its derivatives accounts for 10% to 25% or 10% to 20% of the weight of the flame-retardant insulating film.

[0027] The flame-retardant insulating film of the present application further contains a synergistic additive, and the synergistic additive is a sheet-like inorganic material, and its weight accounts for 0.5% to 6% of the weight of the flame-retardant insulating film. In some examples, the weight of the synergistic additive accounts for 1% to 4% of the weight of the flame-retardant insulating film. The sheet-like inorganic material used in the present application contains at least one of mica and talc powder. In some examples, the sheet diameter of the sheet-like inorganic material used in the present application is 2 μm to 200 μm. The inventors of the present application have discovered that when the sheet diameter of the sheet-like inorganic material is less than 2 μm, the flame-retardant performance of the flame-retardant insulating film decreases, and when the sheet diameter is greater than 200 μm, the processing performance and mechanical performance of the flame-retardant insulating film decrease. In some examples, the sheet diameter of the sheet-like inorganic material used in the present application is 4 μm to 80 μm. By using a synergistic flame retardant in the flame-retardant insulating film of the present application, it is ensured that the flame-retardant insulating film has excellent flame-retardant performance without the need for a large amount of halogen-free foaming flame retardants or without manufacturing the flame-retardant insulating film very thin. The flame-retardant insulating film of the present application can be manufactured to have a thickness of only 0.08 mm to 3 mm, 0.1 mm to 2.5 mm, or 0.1 mm to 2 mm while still having a flame-retardant performance of grade V-0 under the UL-94 test standard. At the same time, the flame-retardant insulating film of the present application has excellent processing performance and mechanical performance without the need for a large amount of halogen-free foaming flame retardants. In some examples, the insulating film of the present application is manufactured with a structure having a single layer or multiple layers.

[0028] The synergistic additives and halogen-free foaming flame retardants used in this application are synergistic and improve the flame retardant performance of the halogen-free foaming flame retardant, thereby reducing the amount of halogen-free foaming flame retardant used. In particular, the sheet-like inorganic material of this application has a divisible layered structure to obtain thin, flexible sheets. The sheet-like inorganic material used in this application is chemically inert and has excellent thermal stability, which enhances the flame retardant effect and promotes char formation in this application. The crystalline structure of the sheet-like inorganic material influences the synergistic effect with the halogen-free foaming flame retardant. Tetrahedral SiO4 sheets on both sides of the interlayer space lead to a better synergistic effect. Silicates reinforce the carbon-containing and char-containing layers produced by the halogen-free foaming flame retardant during combustion, further strengthening the physical barrier, protecting the plastic matrix from combustion heat, separating oxygen, and delaying the release of flammable materials during the combustion and decomposition of the polymer. Furthermore, the sheet-like inorganic material is conductive, captures free radicals, interrupts the combustion cycle, and has a synergistic effect with the plastic material, thereby improving flame retardancy while reducing the amount of flame retardant in the formulation.

[0029] The flame-retardant insulating film of this application may further contain a flame-retardant additive, the weight of which accounts for 0% to 15% of the weight of the flame-retardant insulating film. In some examples, the weight of the flame-retardant additive accounts for 0% to 10% of the weight of the flame-retardant insulating film. In some examples, the flame-retardant additive includes melamine cyanurate (MCA).

[0030] The flame-retardant insulating film of the present invention may further contain a char-forming agent, the weight of which accounts for 0% to 2% of the weight of the flame-retardant insulating film. In some examples, the char-forming agent is selected from at least one of pentaerythritol and triazine.

[0031] The flame-retardant insulating film of this application may further contain additional flame retardants, the weight of which may account for 0% to 5% of the weight of the flame-retardant insulating film. In some examples, the weight of the additional flame retardant may account for 0% to 2% of the weight of the flame-retardant insulating film. In some examples, the additional flame retardant may contain alkyl hypophosphite. In some examples, the alkyl hypophosphite may be diethyl hypophosphite.

[0032] The flame-retardant insulating film of this application may also contain functional additives. In some examples, the weight of the functional additive accounts for 0% to 10% of the weight of the flame-retardant insulating film. In some examples, the functional additive is selected from at least one of lubricants and colorants.

[0033] The composition and content of various components of the flame-retardant insulating film are described above in the specification of this application, and it should be understood that the formulations and content of various components of the above-mentioned flame-retardant insulating film composition can be used to formulate other flame-retardant insulating products.

[0034] The effects of the flame-retardant insulating film of this application are shown below by several specific examples and comparative examples of the film. Table 1 shows the components and various component contents of these specific examples and comparative examples of the flame-retardant insulating film, as well as the flame-retardant performance and tensile strength data for each.

[0035] The examples and comparative examples of flame-retardant insulating films in Table 1 were prepared according to the following method. The raw materials for each component in Table 1 were weighed according to the weight percentage content of the components in Table 1, added to a high-speed mixer, and mixed for 10 minutes at a rotation speed of 500 rpm. The mixed raw materials were added to a twin-screw extruder for extrusion, cooling, and granulation. The temperature of the twin-screw extruder was 230°C, and the screw rotation speed was 300 rpm. The resulting granules were dried and extruded into a film, which was then cut into 0.5 mm thick standard test pieces for performance testing. Flame retardancy was tested according to the UL-94 test standard. Tensile strength was tested according to the ASTM D-882 test standard. [Table 1]

[0036] As shown in Table 1, when comparing Comparative Examples 1 and 2, which are flame-retardant insulating films that do not use sheet-like inorganic materials, with Examples 1 to 5, which use sheet-like inorganic materials with a sheet diameter of 2 μm to 200 μm, the flame-retardant insulating film of the present invention has better flame-retardant performance than the film that does not use sheet-like inorganic materials. In particular, according to Table 1, Comparative Examples 1 and 2 can only achieve a V-2 flame retardancy rating under the UL-94 test standard when using a halogen-free foaming flame retardant that accounts for 43% of the weight content and the film thickness is 0.5 mm. However, the flame-retardant insulating film of Example 1 can achieve a V-0 flame retardancy rating under the UL-94 test standard when using the same weight content of halogen-free foaming flame retardant and the film thickness is 0.5 mm. Furthermore, the flame-retardant insulating films of Examples 2 to 5 can also achieve a V-0 flame retardancy rating when using a similar amount or less of halogen-free foaming flame retardant.

[0037] In addition, as shown in Table 1, since it is not necessary to increase the content of halogen-free foaming flame retardant in the flame-retardant insulating film of the present invention in order to improve flame retardancy, the flame-retardant insulating films of Examples 1 to 5 also have excellent tensile strength, similar to Comparative Examples 1 and 2, while maintaining the flame retardancy grade of Examples 1 to 5, and can meet the usage requirements.

[0038] Furthermore, when preparing the flame-retardant insulating film of the present invention according to the above embodiments, the inventors found that the flame-retardant insulating film of the present invention has good processing performance and can be produced continuously and stably.

[0039] The flame-retardant insulating film of this invention can be used in various electrical devices to electrically insulate electrical components by enclosing or partially enclosing them within the electrical device. Examples of such electrical devices include power adapters, power supply units, server power supplies and CPU peripherals, and lithium battery peripherals.

[0040] Figures 1A and 1B are schematic diagrams of the structure of one example of an electrical device including the flame-retardant insulating film of the present invention. As shown in Figures 1A and 1B, the electrical device 100 comprises a housing 101 and electrical components 104 disposed within the housing 101, the portion of which is enclosed by the flame-retardant insulating film 102 of the present invention, thereby constituting electrical insulation of the electrical components 104.

[0041] The flame-retardant insulating film of this application has at least the following technical effects. 1. Reduce the use of halogen-free foaming flame retardants. 2. Even if the flame-retardant insulating film is a very thin film, it has excellent flame-retardant properties, meaning it can meet the requirements for miniaturization and weight reduction of electrical components and can be applied to a wider range of electrical components. 3. It possesses excellent processing capabilities and can produce continuously and stably. 4. It possesses excellent mechanical performance.

[0042] While this disclosure has been described in relation to the exemplary examples outlined above, various alternative forms, modifications, changes, improvements, and / or substantial equivalents may be apparent to those skilled in the art, whether currently known or foreseeable in the near future. Therefore, the exemplary examples of this disclosure described above are illustrative and not intended to limit. Various modifications can be made without departing from the spirit or scope of this disclosure. Accordingly, this disclosure is intended to include all known or previously developed alternative forms, modifications, changes, improvements, and / or substantial equivalents. The technical effects and technical problems described herein are illustrative and not limiting. It should be noted that the examples described herein may have other technical effects and may solve other technical problems.

Claims

1. A flame-retardant insulating film, wherein the flame-retardant insulating film is Polypropylene and A halogen-free foaming flame retardant, wherein its weight accounts for 39% to 50% of the weight of the flame-retardant insulating film, A synergistic additive which is a sheet-like inorganic material with a sheet diameter of 2 μm to 200 μm, wherein the weight of the synergistic additive accounts for 0.5% to 6% of the weight of the flame-retardant insulating film, A flame-retardant insulating film containing [the specified material].

2. The flame-retardant insulating film according to claim 1, wherein the sheet diameter of the sheet-like inorganic material is 4 μm to 80 μm.

3. The flame-retardant insulating film according to claim 2, wherein the sheet-like inorganic material comprises at least one of mica and talc powder.

4. The flame-retardant insulating film according to claim 1, wherein the polypropylene is a linear homopolymer polypropylene or a linear copolymer polypropylene, and the weight of the polypropylene accounts for 45% to 57% of the weight of the flame-retardant insulating film.

5. The flame-retardant insulating film according to claim 1, wherein the halogen-free foaming flame retardant is selected from at least one of ammonium polyphosphate or its derivatives, melamine polyphosphate or its derivatives, and piperazine pyrophosphate or its derivatives.

6. The halogen-free foaming flame retardant comprises ammonium polyphosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, wherein the ammonium polyphosphate or a derivative thereof accounts for 17% to 35% of the weight of the flame-retardant insulating film, and the melamine polyphosphate or a derivative thereof accounts for 10% to 25% of the weight of the flame-retardant insulating film, as described in claim 5.

7. The halogen-free foaming flame retardant comprises piperazine pyrophosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, wherein the piperazine pyrophosphate or a derivative thereof accounts for 17% to 35% of the weight of the flame-retardant insulating film, and the melamine polyphosphate or a derivative thereof accounts for 10% to 25% of the weight of the flame-retardant insulating film, as described in claim 5.

8. The flame-retardant insulating film further comprises a flame-retardant additive and a char-forming agent. The weight of the flame retardant additive accounts for less than 15% of the weight of the flame retardant insulating film, and the flame retardant additive contains melamine cyanurate. The weight of the char-forming agent accounts for less than 2% of the weight of the flame-retardant insulating film, and the char-forming agent is selected from at least one of pentaerythritol and triazine. The flame-retardant insulating film according to claim 1.

9. The flame-retardant insulating film according to claim 1, further comprising an additional flame retardant, the weight of which is less than 5% of the weight of the flame-retardant insulating film, and the additional flame retardant comprising an alkyl hypophosphite.

10. The flame-retardant insulating film is the flame-retardant insulating film according to claim 1, wherein the flame-retardant insulating film has a thickness of 0.08 mm to 3 mm.

11. The flame-retardant insulating film according to claim 1, wherein the flame-retardant insulating film is manufactured by a melt extrusion molding process.

12. An electrical device (100), wherein the electrical device (100) comprises a housing (101) and an electrical component (104) disposed within the housing (101), The electrical component (104) is enclosed or partially enclosed by the flame-retardant insulating film (102) described in any one of claims 1 to 11. Electrical device (100).

13. The electrical device (100) according to claim 12, wherein the electrical device (100) is a power adapter or a power supply unit.

14. A composition of flame-retardant insulating materials, wherein the composition is Polypropylene and A halogen-free foaming flame retardant, wherein its weight accounts for 39% to 50% of the weight of the aforementioned formulation, A synergistic additive which is a sheet-like inorganic material with a sheet diameter of 2 μm to 200 μm, wherein the weight of the synergistic additive accounts for 0.5% to 6% of the weight of the formulation, A compound containing [something].

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