Flame-retardant insulating film

Abstract

The present application provides a flame-retardant insulating film comprising a polypropylene resin matrix and a halogen-free intumescent flame retardant. The polypropylene resin matrix accounts for 47% to 60% of the weight of the flame-retardant insulating film and includes a high melt strength polypropylene that accounts for 35% to 100% of the weight of the polypropylene resin matrix. The halogen-free intumescent flame retardant accounts for 40% to 60% 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. 202211347640.0, filed on October 31, 2022. Chinese Patent Application No. 202211347640.0 is incorporated herein by reference in its entirety.

[0002] This application relates to the field of films, and in particular to flame-retardant insulating films and electrical components that include flame-retardant insulating films. [Background technology]

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

[0004] The present application provides a flame-retardant insulating film for use in an electronic device or component to meet the insulation and flame-retardant requirements for the electronic device or component. [Means for solving the problem]

[0005] In a first aspect, the present application provides a flame-retardant insulating film comprising a polypropylene resin matrix and a halogen-free intumescent flame retardant. The polypropylene resin matrix accounts for 47% to 60% of the weight of the flame-retardant insulating film and includes high melt strength polypropylene, which accounts for 35% to 100% of the weight of the polypropylene resin matrix. The halogen-free intumescent flame retardant accounts for 40% to 60% of the weight of the flame-retardant insulating film.

[0006] In the above flame-retardant insulating film, the polypropylene resin matrix further comprises standard polypropylene, which accounts for less than 65% by weight of the polypropylene resin matrix.

[0007] In the above flame-retardant insulating film, the halogen-free intumescent flame retardant is selected from at least one of ammonium polyphosphate or a derivative thereof, melamine polyphosphate or a derivative thereof, and piperazine pyrophosphate or a derivative thereof.

[0008] In the above-mentioned flame-retardant insulating film, the halogen-free intumescent flame retardant comprises ammonium polyphosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, and the ammonium polyphosphate or a derivative thereof accounts for 20% 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.

[0009] In the above-mentioned flame-retardant insulating film, the halogen-free intumescent flame retardant comprises piperazine pyrophosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, and the piperazine pyrophosphate or a derivative thereof accounts for 20% 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.

[0010] In the above flame retardant insulating film, the high melt strength polypropylene is a long chain branched polypropylene, the tensile hardness value of the melt is greater than 30 cN, and the polydispersity index of the molecular weight is greater than 4.

[0011] In the above flame-retardant insulating film, the standard polypropylene is a linear homopolymer polypropylene or a linear copolymer polypropylene, and the tensile hardness value of the melt is less than 20 cN.

[0012] The flame-retardant insulating film also includes at least one of a flame-retardant additive, a char-forming agent, and an inorganic filler. The flame-retardant additive accounts for less than 10% of the weight of the flame-retardant insulating film, and the flame-retardant additive includes melamine cyanurate. The char-forming agent accounts for less than 10% of the weight of the flame-retardant insulating film, and is selected from at least one of pentaerythritol and triazine. The inorganic filler accounts for less than 5% of the weight of the flame-retardant insulating film, and is selected from at least one of montmorillonite, talc powder, and mica.

[0013] The above flame-retardant insulating film is produced by a melt extrusion process.

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

[0015] In a second aspect, the present disclosure provides an electrical device comprising a housing and an electrical component disposed within the housing, the electrical component being encapsulated or partially encapsulated by a flame-retardant insulating film according to the present application.

[0016] The electrical device is a power adapter or a power supply unit.

[0017] In a third aspect, the present disclosure provides a formulation for a flame-retardant insulating material, comprising a polypropylene resin matrix and a halogen-free intumescent flame retardant. The polypropylene resin matrix accounts for 47% to 60% by weight of the flame-retardant insulating film and includes a high melt strength polypropylene that accounts for 35% to 100% by weight of the polypropylene resin matrix. The halogen-free intumescent flame retardant accounts for 40% to 60% by weight of the flame-retardant insulating film. [Brief explanation of the drawings]

[0018] [Figure 1A] 1 is a structural schematic diagram of an example electrical device including the flame-retardant insulating film of the present application. [Figure 1B] 1 is a structural schematic diagram of an example electrical device including the flame-retardant insulating film of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0019] Various specific embodiments of the present application are described below with reference to the accompanying drawings, which form a part hereof. While orientational terms such as "front," "rear," "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer" are used herein to describe various exemplary structural components and elements of the present application, it should be understood that these terms are used herein merely for convenience of illustration and are determined based on the exemplary orientations shown in the accompanying drawings. Because the examples disclosed herein can be arranged in different orientations, these orientational terms are for illustrative purposes only and should not be considered limiting.

[0020] In this application, unless otherwise specified, all equipment and raw materials may be purchased from the market or are commonly used in the industry. The methods in the following examples are conventional methods in this field unless otherwise specified.

[0021] Polypropylene film materials are commonly used plastic materials with excellent mechanical properties, processing, and molding capabilities, and relatively low cost. They are widely used, for example, as insulating films in the electrical field. However, polypropylene film materials themselves have poor flame retardancy, and to obtain flame-retardant insulating films, it is often necessary to improve their flame retardancy by adding flame retardants. The present inventors have found that the flame retardancy of flame-retardant insulating films is related to the thickness of the flame-retardant insulating film and the amount of flame retardant added. Generally, the thicker the flame-retardant insulating film, the better the flame retardancy. However, thick flame-retardant insulating films cannot meet the development requirements for lightweight and compact electrical components such as power adapters and batteries. To meet the development requirements for lightweight and compact electrical components such as power adapters and batteries, it is desirable to produce thinner flame-retardant insulating films.

[0022] The inventors of the present application 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 found that increasing the amount of flame retardant can result in a decrease in the mechanical and processability of the flame-retardant insulating film, potentially leading to an uneven surface. Furthermore, to eliminate the environmental impact of flame retardants, it is necessary to use halogen-free flame retardants. However, because halogen-free flame retardants are costly, increasing the amount of halogen-free flame retardant used can potentially increase manufacturing costs.

[0023] The inventors of the present application have found that although high melt strength polypropylene is not flame retardant by itself, blending high melt strength polypropylene with a halogen-free intumescent flame retardant can ensure that the flame retardant insulating film has good flame retardancy without having to increase the thickness of the flame retardant insulating film or the amount of halogen-free intumescent flame retardant. Therefore, the present application can provide an environmentally friendly, thin flame retardant insulating film that has good flame retardancy while using a small amount of halogen-free intumescent flame retardant.

[0024] The flame-retardant insulating film of the present application includes a polypropylene resin matrix, the weight of which accounts for 47% to 60% of the weight of the flame-retardant insulating film. In some examples, the weight of the polypropylene resin matrix accounts for 47% to 55% of the weight of the flame-retardant insulating film. In some examples, the polypropylene resin matrix is ​​composed of high melt strength polypropylene. In some other examples, the polypropylene resin matrix includes high melt strength polypropylene and general polypropylene, with the high melt strength polypropylene accounting for more than 35% or 50% to 100% of the weight of the polypropylene resin matrix. The general polypropylene accounts for less than 65% or 0% to 50% of the weight of the polypropylene resin matrix. In some examples, the high melt strength polypropylene is a long-chain branched polypropylene, with a tensile hardness value of the melt greater than 30 cN and a molecular weight polydispersity index greater than 4. Furthermore, the general polypropylene is a linear homopolymer polypropylene or a linear copolymer polypropylene.

[0025] The flame-retardant insulation film of the present application also includes a halogen-free intumescent flame retardant, the weight of which accounts for 40% to 60% of the weight of the flame-retardant insulation film. In some examples, the weight of the halogen-free intumescent flame retardant accounts for 42% to 50% of the weight of the flame-retardant insulation film. The halogen-free intumescent flame retardant is selected from at least one of ammonium polyphosphate (APP) or a derivative thereof, melamine polyphosphate (MPP) or a derivative thereof, and piperazine pyrophosphate (PAPP) or a derivative thereof. In some examples, the halogen-free intumescent flame retardant is composed of APP or a derivative thereof and MPP or a derivative thereof, the weight of the APP or a derivative thereof accounts for 20% to 35% or 23% to 30% of the weight of the flame-retardant insulation film, and the weight of the MPP or a derivative thereof accounts for 10% to 25% or 13% to 20% of the weight of the flame-retardant insulation film. In some other examples, the halogen-free intumescent flame retardant comprises PAPP or a derivative thereof and MPP or a derivative thereof, the weight of the PAPP or a derivative thereof being 20% ​​to 35% or 23% to 30% of the weight of the flame-retardant insulation film, and the weight of the MPP or a derivative thereof being 10% to 25% or 13% to 20% of the weight of the flame-retardant insulation film.

[0026] The flame-retardant insulating film of the present application can further include a flame-retardant additive, the weight of which accounts for 0% to 10% of the weight of the flame-retardant insulating film. In some examples, the weight of the flame-retardant additive accounts for 0% to 5% of the weight of the flame-retardant insulating film. In some examples, the flame-retardant additive includes melamine cyanurate (MCA).

[0027] The flame-retardant insulating film of the present application may further include a char-forming agent, the weight of which accounts for 0% to 10% of the weight of the flame-retardant insulating film. In some examples, the weight of the char-forming agent accounts for 0% to 4% 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.

[0028] The flame-retardant insulating film of the present application can further include an additional flame retardant, the weight of which accounts for 0% to 5% of the weight of the flame-retardant insulating film. In some examples, the weight of the additional flame retardant accounts for 0% to 2% of the weight of the flame-retardant insulating film. In some examples, the additional flame retardant includes an alkyl hypophosphite. In some examples, the alkyl hypophosphite is diethyl hypophosphite.

[0029] The flame-retardant insulation film of the present application may also include an inorganic filler. In some examples, the inorganic filler accounts for 0% to 5% by weight of the flame-retardant insulation film. In some examples, the inorganic filler is selected from at least one of montmorillonite, talc powder, and mica. In some examples, the inorganic filler is a sheet-like inorganic material.

[0030] The flame-retardant insulating film of the present application may also include a functional additive. In some examples, the weight of the functional additive is 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 a lubricant and a colorant.

[0031] By using high-melt strength polypropylene, the flame-retardant performance of the present flame-retardant insulating film is improved compared to that of a flame-retardant insulating film using only standard polypropylene. This is primarily due to the fact that high-melt strength polypropylene increases the overall melt strength, reduces the risk of dripping (ignition), and makes the char formation process smoother (and more severe). Because of the improved flame-retardant performance of the present flame-retardant insulating film, the present flame-retardant insulating film does not need to be very thick to achieve excellent flame-retardant effectiveness. The present flame-retardant insulating film can be manufactured to 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 achieving flame-retardant performance of V-0 under UL-94 testing standards. In some examples, the present insulating film is manufactured in a single-layer or multi-layer structure. At the same time, the present flame-retardant insulating film does not require large amounts of halogen-free intumescent flame retardants due to its improved flame-retardant performance. The flame retardant insulating film of the present application has excellent processing and mechanical properties without requiring large amounts of halogen-free intumescent flame retardants.

[0032] Although the composition of the flame retardant insulation film and the content of various ingredients are described above in the specification of this application, it should be understood that the formulation of the composition of the flame retardant insulation film and the content of various ingredients described above can be used to formulate other flame retardant insulation products.

[0033] The effectiveness of the flame-retardant insulating film of the present application is demonstrated below by several specific examples of the present application and comparative examples of flame-retardant insulating films. Table 1 shows the components and contents of various components in these specific examples and comparative examples of flame-retardant insulating films, as well as their respective flame-retardant performance and tensile strength data.

[0034] The flame-retardant insulation film examples and comparative examples 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 percent content of the component in Table 1 and 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 films, which were then cut into standard test specimens of consistent thickness (e.g., all 0.5 mm thick) for performance testing. Flame retardancy performance was tested according to UL-94 test standards. Tensile strength was tested according to ASTM D-882 test standards. [Table 1]

[0035] As shown in Table 1, when comparing Comparative Examples 1 and 2, which are flame-retardant insulating films that do not use high-melt strength polypropylene, with Examples 1 to 6 of the present application, which use high-melt strength polypropylene, the flame-retardant insulating films of the present application have better flame retardancy than films that do not use high-melt strength polypropylene. To achieve the same flame retardancy, Examples 1 to 6 of the present application require less halogen-free intumescent flame retardant than Comparative Examples 1 and 2. Alternatively, when the content of halogen-free intumescent flame retardant is the same or similar, Examples 1 to 6 of the present application have better flame retardancy. In particular, Comparative Example 1 can only achieve a V-2 flame retardancy rating under UL-94 test standards when using a halogen-free intumescent flame retardant that accounts for 43% by weight, while Comparative Example 2 can only achieve a V-0 flame retardancy rating when using a halogen-free intumescent flame retardant that accounts for 63% by weight. In contrast to the examples of the present application, Examples 4 and 5 achieved a V-0 flame retardancy rating when using slightly more halogen-free intumescent flame retardant than Comparative Example 1, but much less than Comparative Example 2. On the other hand, Examples 1-3 and 6 used even less halogen-free intumescent flame retardant than Comparative Example 1, and yet the films of Examples 1-3 and 6 similarly achieved a V-0 flame retardancy rating.

[0036] In addition, as shown in Table 1, there is no need to increase the content of the halogen-free intumescent flame retardant in the flame-retardant insulating film of the present application to improve the flame retardant performance. Therefore, the flame-retardant insulating film of the present application also has excellent tensile strength and can meet usage requirements while maintaining its flame retardant grade.

[0037] Furthermore, when preparing the flame-retardant insulating film of the present application according to the above examples, the inventors have found that the flame-retardant insulating film of the present application has good processing performance and can be produced continuously and stably.

[0038] The flame-retardant insulating film of the present application can be used in various electrical devices to encapsulate or partially encapsulate electrical components in order to electrically insulate the electrical components, such as power adapters, power supply units, server power supplies and CPU peripherals, lithium battery peripherals, etc.

[0039] 1A and 1B are schematic structural diagrams of an example of an electrical device including the flame-retardant insulating film of the present application. As shown in Fig. 1A and 1B, the electrical device 100 includes a housing 101 and an electrical component 104 disposed within the housing 101. A portion of the electrical component 104 is encapsulated by the flame-retardant insulating film 102 of the present application, which provides electrical insulation for the electrical component 104.

[0040] The flame-retardant insulating film of the present application has at least the following technical effects. 1. Reduce the use of halogen-free intumescent flame retardants. 2. Even though the flame-retardant insulating film is very thin, it still has excellent flame-retardant properties, which means 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 has excellent processing performance and can be produced continuously and stably. 4. Excellent mechanical properties.

[0041] While the present disclosure has been described in connection with the illustrative examples outlined above, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or foreseeable now or in the near future, may be apparent to at least those skilled in the art. Accordingly, the illustrative examples of the present disclosure set forth above are illustrative and not intended to be limiting. Various changes may be made without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is intended to include all known or previously developed alternatives, modifications, variations, improvements, and / or substantial equivalents. The technical advantages and technical problems described herein are illustrative and not limiting. It should be noted that the examples described herein may have other technical advantages and may solve other technical problems.

Claims

1. A flame-retardant insulating film, comprising: a polypropylene resin matrix, the weight of which accounts for 47% to 60% of the weight of the flame-retardant insulation film, and the polypropylene resin matrix includes a high melt strength polypropylene, the weight of which accounts for 35% to 100% of the weight of the polypropylene resin matrix; a halogen-free intumescent flame retardant, the weight of which accounts for 40% to 60% of the weight of the flame-retardant insulating film; A flame-retardant insulating film comprising:

2. 10. The flame-retardant insulating film of claim 1, wherein the polypropylene resin matrix further comprises standard polypropylene, the polypropylene comprising less than 65% by weight of the polypropylene resin matrix.

3. 2. The flame-retardant insulating film according to claim 1, wherein the halogen-free intumescent flame retardant is selected from at least one of ammonium polyphosphate or a derivative thereof, melamine polyphosphate or a derivative thereof, and piperazine pyrophosphate or a derivative thereof.

4. 4. The flame-retardant insulating film according to claim 3, wherein the halogen-free intumescent flame retardant comprises ammonium polyphosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, the ammonium polyphosphate or a derivative thereof occupying 20% ​​to 35% of the weight of the flame-retardant insulating film, and the melamine polyphosphate or a derivative thereof occupying 10% to 25% of the weight of the flame-retardant insulating film.

5. 4. The flame-retardant insulating film according to claim 3, wherein the halogen-free intumescent flame retardant comprises piperazine pyrophosphate or a derivative thereof and melamine polyphosphate or a derivative thereof, and the piperazine pyrophosphate or a derivative thereof accounts for 20% 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.

6. 2. The flame-retardant insulating film according to claim 1, wherein the high melt strength polypropylene is a long-chain branched polypropylene, the melt having a tensile hardness value of greater than 30 cN, and a molecular weight polydispersity index of greater than 4.

7. 2. The flame-retardant insulating film of claim 1, wherein the standard polypropylene is a linear homopolymer polypropylene or a linear copolymer polypropylene, and the melt has a tensile hardness value of less than 20 cN.

8. The flame-retardant insulation film further comprises at least one of a flame-retardant additive, a char-forming agent, and an inorganic filler; the flame retardant additive accounts for less than 10% by weight of the flame retardant insulation film, and the flame retardant additive comprises melamine cyanurate; the char-forming agent accounts for less than 10% by weight of the flame-retardant insulation film, and the char-forming agent is selected from at least one of pentaerythritol and triazine; The inorganic filler accounts for less than 5% by weight of the flame-retardant insulation film, and the inorganic filler is selected from at least one of montmorillonite, talc powder, and mica. The flame-retardant insulating film according to claim 1 .

9. The flame-retardant insulating film of claim 1 , wherein the flame-retardant insulating film is manufactured by a melt extrusion process.

10. 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. An electric device (100), comprising a housing (101) and an electric component (104) disposed within the housing (101); The electrical component (104) is encapsulated or partially encapsulated by the flame-retardant insulating film (102) according to any one of claims 1 to 10. An electrical device (100).

12. The electrical device (100) of claim 11, wherein the electrical device (100) is a power adapter or a power supply unit.

13. 1. A formulation of a flame retardant insulating material, said formulation comprising: a polypropylene resin matrix, the weight of which accounts for 47% to 60% of the weight of the flame-retardant insulation film, and the polypropylene resin matrix includes a high melt strength polypropylene, the weight of which accounts for 35% to 100% of the weight of the polypropylene resin matrix; a halogen-free intumescent flame retardant, the weight of which accounts for 40% to 60% of the weight of the flame-retardant insulating film; 1. A formulation of a flame retardant insulating material comprising:

Images