Production process of flame-retardant thermal insulation foam

Abstract

The invention discloses a production process of flame-retardant thermal insulation foam. The production process of the flame-retardant thermal insulation foam comprises the following steps: S1, raw material pretreatment; s2, burdening and mixing; s3, foaming and curing; s4, post processing; the flame-retardant thermal insulation foam comprises the following components: polyol, isocyanate, a foaming agent, a catalyst, a foam stabilizer and a flame-retardant system, wherein the polyol is polyether polyol; the isocyanate is one or a mixture of two of toluene diisocynate and diphenylmethane diisocyanate; adopting a foaming agent; the catalyst is a mixture of an amine catalyst and an organic tin catalyst; and the foam stabilizer adopts an organic silicon surfactant. According to the production process of the flame-retardant thermal insulation foam, on the basis of production of traditional polyurethane soft foam or polyethylene foam, comprehensive improvement of flame retardance, physical properties and environmental protection performance is achieved through a structure modification and multi-dimensional flame retardant compounding technology.

Description

Technical Field

[0001] This invention relates to the field of foam production technology, and in particular to a production process for flame-retardant thermal insulation foam. Background Technology

[0002] Flexible polyurethane foam (FPF) is widely used in building insulation, furniture padding, automotive interiors, and packaging materials due to its excellent properties such as lightweight, thermal insulation, sound insulation, softness, and good resilience. However, the limiting oxygen index (LOI) of polyurethane foam is typically around 17-18%, classifying it as a flammable material. It burns rapidly upon contact with fire, releasing large amounts of heat and toxic fumes, posing a significant fire hazard. Therefore, the development of flame-retardant insulating foams has become an inevitable requirement for technological advancement in this field.

[0003] Currently, the mainstream technology for flame-retardant modification of polyurethane foam is the addition of flame retardants. Common additive flame retardants mainly include halogenated flame retardants (such as decabromodiphenyl ether, tetrabromobisphenol A, etc.), phosphorus-based flame retardants (such as phosphate esters), nitrogen-based flame retardants (such as melamine), and inorganic flame retardants (such as aluminum hydroxide, expanded graphite, etc.).

[0004] However, existing flame-retardant foam production processes face the following prominent contradictions: the contradiction between halogen-free requirements and high flame-retardant efficiency; the contradiction between high flame retardant dosage and excellent physical properties of the foam; the contradiction between flame-retardant durability and migration / exudation; and the contradiction between the high efficiency of nanomaterials and the difficulty in dispersion. Therefore, there is an urgent need in this field for a new production process that can efficiently, stably, and environmentally impart durable and high-level flame-retardant properties to polyurethane foam without significantly impairing its inherent physical properties, while effectively reducing smoke emissions during combustion. Summary of the Invention

[0005] Therefore, it is necessary to provide a production process for flame-retardant thermal insulation foam to address the technical problems of insufficient comprehensive characteristics of existing foam products in terms of flame retardancy, physical properties, and environmental protection.

[0006] A manufacturing process for flame-retardant thermal insulation foam, comprising the following steps:

[0007] S1. Raw material pretreatment;

[0008] S2, Ingredient preparation and mixing;

[0009] S3, foaming and curing;

[0010] S4. Post-processing.

[0011] Flame-retardant thermal insulation foam includes the following components: polyol, isocyanate, foaming agent, catalyst, foam stabilizer, and flame-retardant system.

[0012] Preferably, the polyol is a polyether polyol (functionality 2-3, molecular weight 3000-5000) to form the foam soft segment matrix.

[0013] Preferably, the isocyanate is one or a mixture of two of toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) to form the foam hard segment matrix, which reacts with the polyol.

[0014] Preferably, the foaming agent is H2O, which reacts with isocyanate to generate CO2, thereby achieving environmentally friendly physical foaming.

[0015] Preferably, the catalyst is a mixture of amine catalysts and organotin catalysts to synergistically catalyze the foaming and gelation reactions.

[0016] Preferably, the foam stabilizer uses an organosilicon surfactant to stabilize the cell structure and prevent collapse.

[0017] Preferably, the flame retardant system includes: a reactive flame retardant: a flame-retardant polyol containing phosphorus / nitrogen elements; an additive flame retardant: microencapsulated ammonium polyphosphate (MCAPP) and melamine cyanurate (MCA) with surface modification treatment; and a nano-synergist: nanoscale layered double hydroxide (LDH). The reactive flame retardant is chemically bonded to the polymer chain, providing permanent flame retardancy and preventing migration; the combination of MCAPP and MCA forms an intumescent barrier layer, while microencapsulation prevents reaction with raw materials and improves dispersibility; and LDH (nanosheets) forms a dense carbon layer in the condensed phase, adsorbing toxic gases and significantly reducing smoke density.

[0018] In one embodiment, the flame-retardant thermal insulation foam described above comprises the following components by weight: polyether polyol: 100 parts; reactive flame-retardant polyol: 15-25 parts; TDI / MDI index: 105-110; H2O: 2.0-3.5 parts; amine catalyst: 0.2-0.5 parts; tin catalyst: 0.1-0.3 parts; silicone oil surfactant: 1.0-1.5 parts; MCAPP: 8-12 parts; MCA: 5-8 parts; nano LDH: 2-4 parts.

[0019] In one embodiment, step S1 above includes the following steps:

[0020] S11, Nano LDH Dispersion: Nano LDH powder is pre-dispersed in a portion of polyether polyol using a high-speed shear machine (>3000rpm) to form a stable and uniform slurry and prevent subsequent agglomeration;

[0021] S12. Drying of powdered flame retardants: Powdered flame retardants such as MCAPP and MCA need to be dried in a forced-air dryer at 80°C for 4 hours to remove moisture and prevent unnecessary side reactions during the foaming process.

[0022] In one embodiment, in step S11 above, the dispersion time of the nano-LDH powder pre-dispersed in a portion of the polyether polyol is set to 30 minutes.

[0023] In one embodiment, step S2 above includes the following steps:

[0024] S21, Component A Premix: Add polyether polyol, reactive flame retardant polyol, nano LDH slurry, catalyst, silicone oil, foaming agent water, and all additives such as MCAPP and MCA into the Component A premix tank; stir at low speed (500-800 rpm) for 30 minutes at room temperature to ensure that all components are extremely uniformly dispersed.

[0025] S22, Component B: Isocyanate is stored separately in container B, with the temperature kept constant at 25±1℃;

[0026] S23. Mixing process: A high-pressure foaming machine is used. Components A and B are fed into the high-pressure mixing head in proportion by a high-precision metering pump (accuracy ±0.5%). The components are violently impacted and mixed under a high pressure of 10-15MPa for 1-3 seconds to ensure uniform mixing and prevent premature reaction.

[0027] In one embodiment, in step S21 above, after component A is dispersed, a vacuum of -0.05 MPa is applied to remove air bubbles introduced during stirring, and the degassing time is set to 10 minutes.

[0028] In one embodiment, in step S21 above, the temperature of tank A is kept constant at 25±1℃.

[0029] In one embodiment, in step S23 above, the mixing head temperature is set to 30°C.

[0030] In one embodiment, step S3 above includes the following steps:

[0031] S31. Pouring: The mixed slurry is quickly poured onto a continuously running conveyor belt (for producing block foam) or a mold (for molding), wherein the paper lining of the conveyor belt is pre-sprayed with a release agent.

[0032] S32. Foaming: The conveyor belt enters the high-temperature curing channel; the temperature is controlled in stages: Stage 1: 50-60℃ (initiating the reaction, controlling the milky white time and rise time); Stage 2: 70-80℃ (promoting the completion of the reaction and reaching the maximum temperature); Stage 3: 40-50℃ (slow cooling and stabilizing the dimensions).

[0033] S33. Curing: The large foam block after foaming needs to be placed at room temperature for at least 24 hours to allow the reaction to completely end in order to achieve the final mechanical properties and dimensional stability.

[0034] In one embodiment, step S4 above includes the following steps:

[0035] S41. Cutting: Use a large longitudinal and transverse cutting machine to cut the foam block into sheets of the required thickness;

[0036] S42. Surface treatment: Aluminum foil and fiberglass cloth are laminated onto the surface of the sheet to further improve its flame retardancy and physical properties;

[0037] S43. Performance Testing: Sample the finished product and test key indicators such as density, oxygen index (LOI), vertical burning (UL94), thermal conductivity, and tensile strength.

[0038] In one embodiment, the flame-retardant thermal insulation foam comprises the following components by weight: Component A: polyether triol (molecular weight 3000): 80 parts; reactive flame-retardant polyether polyol: 20 parts; nano LDH: 10 parts; MCAPP: 10 parts; MCA: 7 parts; silicone foam stabilizer: 1.2 parts; amine catalyst: 0.3 parts; deionized water: 3.0 parts; Component B: toluene diisocyanate: 41.2 parts.

[0039] In one embodiment, the temperature segmentation control in step S32 is defined as follows: Stage 1: 55°C, time approximately 3-4 minutes, to allow the foam to initially gel and set; Stage 2: 75°C, time approximately 5-6 minutes, to promote complete reaction and achieve final strength; Stage 3: 45°C, supplemented by forced ventilation, slow cooling, stabilizing dimensions, and preventing shrinkage.

[0040] The aforementioned production process for flame-retardant thermal insulation foam, based on the traditional production of polyurethane flexible foam or polyethylene foam, achieves a comprehensive improvement in flame-retardant performance, physical properties, and environmental performance through structural modification and multi-dimensional flame retardant compounding technology. Specifically, based on a compound system of reactive flame retardant + nano-LDH + microencapsulated APP / MCA, a dual synergistic flame-retardant effect of gas-phase dilution cooling and condensed phase dense carbon layer is achieved, resulting in high flame-retardant efficiency and durability without precipitation; the halogen-free system, coupled with the excellent smoke suppression effect of nano-LDH, significantly reduces secondary hazards in fires, ensuring the environmental friendliness and safety of the foam; through optimized mixing and catalytic systems, as well as the reinforcing effect of nanomaterials, fine and uniform cell structure is ensured, avoiding a significant decrease in mechanical properties caused by the addition of large amounts of flame retardant; this solution is based on existing mature polyurethane foaming equipment, only upgrading the raw material pretreatment and formulation system, resulting in low modification costs and easy large-scale stable production. Detailed Implementation

[0041] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0046] Example 1

[0047] This invention discloses a manufacturing process for flame-retardant thermal insulation foam, which includes the following steps:

[0048] S1. Raw material pretreatment;

[0049] S2, Ingredient preparation and mixing;

[0050] S3, foaming and curing;

[0051] S4. Post-processing.

[0052] Furthermore, flame-retardant thermal insulation foam includes the following components: polyol, isocyanate, foaming agent, catalyst, foam stabilizer, and flame-retardant system.

[0053] Preferably, the polyol is a polyether polyol (functionality 2-3, molecular weight 3000-5000) to form the foam soft segment matrix.

[0054] Preferably, the isocyanate is one or a mixture of two of toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) to form the foam hard segment matrix, which reacts with the polyol.

[0055] Preferably, the foaming agent is H2O, which reacts with isocyanate to generate CO2, thereby achieving environmentally friendly physical foaming.

[0056] Preferably, the catalyst is a mixture of amine catalysts and organotin catalysts to synergistically catalyze the foaming and gelation reactions.

[0057] Preferably, the foam stabilizer uses an organosilicon surfactant to stabilize the cell structure and prevent collapse.

[0058] Preferably, the flame retardant system includes: a reactive flame retardant: a flame-retardant polyol containing phosphorus / nitrogen elements; an additive flame retardant: microencapsulated ammonium polyphosphate (MCAPP) and melamine cyanurate (MCA) with surface modification treatment; and a nano-synergist: nanoscale layered double hydroxide (LDH). The reactive flame retardant is chemically bonded to the polymer chain, providing permanent flame retardancy and preventing migration; the combination of MCAPP and MCA forms an intumescent barrier layer, while microencapsulation prevents reaction with raw materials and improves dispersibility; and LDH (nanosheets) forms a dense carbon layer in the condensed phase, adsorbing toxic gases and significantly reducing smoke density.

[0059] Based on this, in this embodiment, the flame-retardant thermal insulation foam comprises the following components by weight:

[0060] Polyether polyol: 100 parts;

[0061] Reactive flame-retardant polyols: 15-25 parts;

[0062] TDI / MDI index: 105-110;

[0063] H2O: 2.0-3.5 parts;

[0064] Amine catalyst: 0.2-0.5 parts;

[0065] Tin catalyst: 0.1-0.3 parts;

[0066] Silicone oil surfactant: 1.0-1.5 parts;

[0067] MCAPP: 8-12 servings;

[0068] MCA: 5-8 copies;

[0069] Nano LDH: 2-4 parts.

[0070] Based on the above formula, in this embodiment, specifically, step S1 includes the following steps:

[0071] S11, Nano LDH Dispersion: Nano LDH powder is pre-dispersed in a portion of polyether polyol using a high-speed shear machine (>3000rpm) to form a stable and uniform slurry and prevent subsequent agglomeration;

[0072] S12. Drying of powdered flame retardants: Powdered flame retardants such as MCAPP and MCA need to be dried in a forced-air dryer at 80°C for 4 hours to remove moisture and prevent unnecessary side reactions during the foaming process.

[0073] Furthermore, in step S11 above, the dispersion time of the nano-LDH powder pre-dispersed in a portion of the polyether polyol is set to 30 minutes.

[0074] Specifically, step S2 above includes the following steps:

[0075] S21, Component A Premix: Add polyether polyol, reactive flame retardant polyol, nano LDH slurry, catalyst, silicone oil, foaming agent water, and all additives such as MCAPP and MCA into the Component A premix tank; stir at low speed (500-800 rpm) for 30 minutes at room temperature to ensure that all components are extremely uniformly dispersed.

[0076] S22, Component B: Isocyanate is stored separately in container B, with the temperature kept constant at 25±1℃;

[0077] S23. Mixing process: A high-pressure foaming machine is used. Components A and B are fed into the high-pressure mixing head in proportion by a high-precision metering pump (accuracy ±0.5%). The components are violently impacted and mixed under a high pressure of 10-15MPa for 1-3 seconds to ensure uniform mixing and prevent premature reaction.

[0078] Furthermore, in step S21 above, after component A is dispersed, a vacuum of -0.05 MPa is applied to remove air bubbles introduced during stirring, and the degassing time is set to 10 minutes.

[0079] Furthermore, in step S21 above, the temperature of tank A is kept constant at 25±1℃.

[0080] Furthermore, in step S23 above, the mixing head temperature is set to 30°C.

[0081] Specifically, step S3 above includes the following steps:

[0082] S31. Pouring: The mixed slurry is quickly poured onto a continuously running conveyor belt (for producing block foam) or a mold (for molding), wherein the paper lining of the conveyor belt is pre-sprayed with a release agent.

[0083] S32. Foaming: The conveyor belt enters the high-temperature curing channel; the temperature is controlled in stages: Stage 1: 50-60℃ (initiating the reaction, controlling the milky white time and rise time); Stage 2: 70-80℃ (promoting the completion of the reaction and reaching the maximum temperature); Stage 3: 40-50℃ (slow cooling and stabilizing the dimensions).

[0084] S33. Curing: The large foam block after foaming needs to be placed at room temperature for at least 24 hours to allow the reaction to completely end in order to achieve the final mechanical properties and dimensional stability.

[0085] Specifically, step S4 above includes the following steps:

[0086] S41. Cutting: Use a large longitudinal and transverse cutting machine to cut the foam block into sheets of the required thickness;

[0087] S42. Surface treatment: Aluminum foil and fiberglass cloth are laminated onto the surface of the sheet to further improve its flame retardancy and physical properties;

[0088] S43. Performance Testing: Sample the finished product and test key indicators such as density, oxygen index (LOI), vertical burning (UL94), thermal conductivity, and tensile strength.

[0089] Example 2

[0090] Unlike Example 1, the flame-retardant thermal insulation foam in this example includes the following components by weight: Component A: Polyether triol (molecular weight 3000): 80 parts;

[0091] Reactive flame-retardant polyether polyol: 20 parts;

[0092] Nano LDH: 10 parts;

[0093] MCAPP: 10 copies;

[0094] MCA: 7 copies;

[0095] Organosilicon foam stabilizer: 1.2 parts;

[0096] Amine catalyst: 0.3 parts;

[0097] Deionized water: 3.0 parts;

[0098] Component B: Toluene diisocyanate: 41.2 parts.

[0099] In this embodiment, the temperature segmentation control in step S32 is limited to: the first stage: 55°C, for about 3-4 minutes, to allow the foam to initially gel and solidify; the second stage: 75°C, for about 5-6 minutes, to promote complete reaction and reach final strength; and the third stage: 45°C, supplemented by forced ventilation, slow cooling, stabilizing size and preventing shrinkage.

[0100] In summary, the production process of flame-retardant thermal insulation foam disclosed in this invention, based on the traditional production of polyurethane flexible foam or polyethylene foam, achieves a comprehensive improvement in flame-retardant performance, physical properties, and environmental performance through structural modification and multi-dimensional flame retardant compounding technology. Specifically, based on a compound system of reactive flame retardant + nano-LDH + microencapsulated APP / MCA, a dual synergistic flame-retardant effect of gas-phase dilution cooling and condensed phase dense carbon layer is achieved, resulting in high flame-retardant efficiency and durability without precipitation; the halogen-free system, and the excellent smoke suppression effect of nano-LDH, greatly reduces secondary hazards in fires, ensuring the environmental friendliness and safety of the foam; through optimized mixing and catalytic systems, as well as the reinforcing effect of nanomaterials, fine and uniform cell structure is ensured, avoiding a significant decrease in mechanical properties caused by the addition of large amounts of flame retardant; this solution is based on existing mature polyurethane foaming equipment, only upgrading the raw material pretreatment and formulation system, resulting in low modification costs and easy large-scale stable production.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A production process of a flame-retardant thermal insulation foam, characterized in that, The method comprises the following steps: S1, raw material pretreatment; S2, batching and mixing; S3, foaming and curing; S4, post-processing; The fire-retardant thermal insulation foam comprises the following components: polyol, isocyanate, foaming agent, catalyst, foam stabilizer and fire-retardant system; wherein the polyol is polyether polyol; the isocyanate is one or a mixture of two of toluene diisocyanate and diphenylmethane diisocyanate; the foaming agent is ; the catalyst is a mixture of amine catalyst and organic tin catalyst; the foam stabilizer is organic silicon surfactant; the fire-retardant system comprises: reactive fire retardant: fire-retardant polyol containing phosphorus / nitrogen elements; additive fire retardant: microencapsulated ammonium polyphosphate and melamine cyanurate treated by surface modification; nano synergist: nanoscale layered double hydroxide.

2. The production process of the flame-retardant thermal insulation foam according to claim 1, characterized in that, The fire-retardant thermal insulation foam includes the following components by weight fraction: polyether polyol: 100 parts; reactive flame-retardant polyol: 15-25 parts; TDI / MDI index: 105-110; : 2.0-3.5 parts; amine catalyst: 0.2-0.5 parts; tin catalyst: 0.1-0.3 parts; silicone oil surfactant: 1.0-1.5 parts; MCAPP: 8-12 parts; MCA: 5-8 parts; nano LDH: 2-4 parts.

3. The production process of the flame-retardant thermal insulation foam according to claim 2, characterized in that, Step S1 comprises the following steps: S11, nano LDH dispersion: using a high-speed shearing machine to pre-disperse nano LDH powder in part of the polyether polyol to form a stable and uniform slurry, preventing subsequent agglomeration; S12, powder flame retardant drying: MCAPP, MCA and other powder flame retardants need to be dried at 80°C for 4 hours by blowing, removing moisture, and preventing unnecessary side reactions during foaming.

4. The production process of the flame-retardant thermal insulation foam according to claim 3, characterized in that, In step S11, the dispersion time of pre-dispersing nano LDH powder in part of the polyether polyol is set to 30 minutes.

5. The production process of the flame-retardant thermal insulation foam according to claim 4, characterized in that, Step S2 comprises the following steps: S21, A component premixing: polyether polyol, reactive flame-retardant polyol, nano LDH slurry, catalyst, silicone oil, foaming agent water, and all additives such as MCAPP and MCA are put into an A material premixing tank; stirring at low speed for 30 minutes at room temperature to ensure that all components are extremely uniformly dispersed; S22, B component: isocyanate is stored separately in a B tank, and the temperature is kept constant at 25±1°C; S23, mixing process: using a high-pressure foaming machine, A and B components are sent to the high-pressure mixing head through high-precision metering pumps according to the proportion; mixing under high pressure of 10-15 MPa, mixing for 1-3 seconds to ensure uniform mixing and prevent premature reaction.

6. The production process of the flame-retardant thermal insulation foam according to claim 5, characterized in that, In step S21, after the dispersion of A component is completed, a vacuum degree of -0.05 MPa is applied to remove the air bubbles brought in during stirring, and the defoaming time is set to 10 minutes.

7. The production process of the flame-retardant thermal insulation foam according to claim 6, characterized in that, In step S21, the temperature of the A tank is kept constant at 25±1°C.

8. The production process of the flame-retardant thermal insulation foam according to claim 7, characterized in that, In step S23, the temperature of the mixing head is set to 30°C.

9. The production process of the flame-retardant thermal insulation foam according to claim 8, characterized in that, Step S3 comprises the following steps: S31, pouring: the mixed slurry is quickly poured onto a continuously running conveyor belt, wherein the conveyor belt paper lining is pre-sprayed with a release agent; S32, foaming: the conveyor belt enters a high-temperature curing channel; temperature is controlled in stages: first stage: 50-60°C; second stage: 70-80°C; third stage: 40-50°C; S33, curing: the huge foam block after foaming needs to be placed at room temperature for at least 24 hours to allow the reaction to complete, so as to achieve the final mechanical properties and dimensional stability.

10. The production process of the flame-retardant thermal insulation foam according to claim 9, characterized in that, Step S4 comprises the following steps: S41, cutting: using a large longitudinal and transverse cutting machine to cut the foam block into sheets of the required thickness; S42, surface treatment: composite aluminum foil and glass cloth on the surface of the sheet to further improve the flame retardation and physical properties; S43, performance testing: sampling the finished product to test key indicators such as density, oxygen index, vertical burning, thermal conductivity, tensile strength, etc.

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