Polyurethane flame retardant fire extinguishing composite sheet and preparation method thereof

Abstract

The present invention provides a polyurethane flame retardant and fire extinguishing composite sheet, which comprises at least two layers: a fire extinguishing layer and a polyurethane continuous phase layer, wherein the fire extinguishing layer is located on the surface of the polyurethane continuous phase layer and contains fire extinguishing medium particles, including a floating layer and an embedded layer, and the floating rate fn of the fire extinguishing medium particles in the material is 0.25-0.8, preferably 0.4-0.7, which is defined as the ratio of the thickness H1 of the floating layer to the average value of the polar length L of the particles. By controlling the floating state of the particles, the material can maintain good tensile properties and tear strength while maintaining high flame retardancy and fire extinguishing properties, and is convenient for paving and construction.

Description

Technical Field

[0001] The invention relates to the field of fire-extinguishing composite materials, and in particular to a flame-retardant fire-extinguishing composite sheet material with polyurethane as a base material. Background Art

[0002] At present, polymer materials are widely used and have many advantages in physical properties that traditional materials do not have. However, the non-flammability and fire resistance of most polymer materials themselves affect the personal safety of people who use the materials. Fireproof materials are used in many fields, mainly in the construction field, such as walls, insulation layers, roofs, etc. In buildings, the use of fireproof materials can effectively reduce the number of fires and reduce the degree of damage caused by fires. Fireproof materials have also been widely used in the field of transportation. For example, in transportation vehicles such as airplanes, trains, and subways, many ministries and commissions need to use fireproof materials to ensure the safety of passengers, because the space of transportation vehicles is relatively small. Once a fire occurs, the fire will spread quickly and easily threaten people's lives. Fireproof materials are also very important in the field of power equipment. Fireproof materials are needed in power stations, transmission equipment, substation equipment, cables, electrical cabinets and other locations or facilities to prevent fires. Commonly used fireproof materials include refractory materials, flame retardant materials, fireproof insulation materials, fireproof fillers, fireproof boards, flame retardant boards, fireproof coatings, etc. Various types of fireproofing materials are used in different application areas.

[0003] At present, the polymer-based fireproof materials commonly used in the market are mainly made by filling or compounding.

[0004] The method of filling with inorganic / organic flame retardant particles is a relatively common method of producing flame retardant / fireproof products. In CN116889694A, perfluorohexanone microcapsules are filled into the substrate layer. The main feature of this processing method is that the surface of the processed product is dense and smooth, and the appearance is good, which can basically meet the flame retardant test grade requirements. However, in this invention, mechanical stirring is used to mix the raw materials. The defect of this scheme is that the proportion of the mixed materials is limited. If too much inorganic / organic powder is added, the viscosity of the system will be further increased, which will make the finished product difficult to process. Therefore, the product obtained by this invention cannot have both good fire extinguishing function and processing performance.

[0005] In addition, surface (usually single-sided or double-sided polymer materials) composite inorganic refractory materials are also common flame retardant / fire extinguishing materials on the market. This material is currently widely used in battery thermal runaway management, can play an ideal flame retardant and fireproof role, and has a good surface state, so the material has the function of flame retardant and preventing the spread of flames. However, in order to have a better flame retardant effect, the existing technology increases the thickness of the composite material, which will also lead to a decrease in the toughness of the material, and then lead to a decrease in impact resistance. At the same time, the material can only prevent the spread of flames, but cannot prevent the spread and penetration of heat. In addition, the material does not have the function of active fire extinguishing.

[0006] Another flame retardant and fire extinguishing method in the prior art is to synthesize flame retardant composite materials. The specific idea is to introduce and graft flame retardant groups onto the materials during the synthesis of polymer materials. The material is simple to synthesize, has good physical properties, and can maintain toughness and tensile strength for a long time. However, it can only meet the basic HBF level in the fire retardant test-UL94HB level combustion grade test, and cannot further achieve the purpose of fire prevention or active fire extinguishing.

[0007] CN117018529A mixes fire extinguishing microcapsules and resin medium, and applies them on a substrate to prepare a fire extinguishing tape. However, in order to reduce the possibility of loss and failure of the active ingredients, it is necessary to ensure that the fire extinguishing microcapsules are not exposed. The fire extinguishing performance is general and the process is relatively complicated.

[0008] It can be seen that in the prior art, when the amount of fire extinguishing medium added to the blended fire extinguishing agent is small, fire blocking and fire extinguishing cannot be achieved in time. When the amount added is large, the material loses fluidity. In addition, the method of blending fire extinguishing agents is difficult to process. The blending method will greatly reduce the physical properties of the material, and defects are prone to occur in the rolls. In addition, when the fire extinguishing medium is added in large particles, it is difficult to form, and when small particles are used, the fire extinguishing effect is poor.

[0009] Based on the above-mentioned defects of the prior art, it is necessary to propose a material that has excellent processing performance, mechanical properties and flame retardant and fire extinguishing performance. Summary of the invention

[0010] In view of the defects existing in the prior art, the purpose of the present invention is to provide a polyurethane flame retardant and fire extinguishing composite sheet and a preparation method thereof, aiming to solve the problem of being able to take into account processing performance, mechanical properties and flame retardant and fire extinguishing performance when containing a flame retardant and fire extinguishing medium. The prepared finished product has excellent toughness and tensile properties to meet the flatness and interface tracking properties during the paving process, avoiding the problem of easy tearing under tension conditions during material processing.

[0011] The inventors have conducted in-depth research to solve the above-mentioned problems and found that by controlling the floating state of the fire extinguishing medium particles in the polyurethane flame retardant and fire extinguishing composite sheet, the material can maintain the tensile properties and tear strength of the material while achieving high flame retardancy and fire extinguishing performance, thereby making the material easy to lay and construct.

[0012] The specific plan is as follows:

[0013] In a first aspect, the present invention discloses a polyurethane flame retardant and fire extinguishing composite sheet, the flame retardant and fire extinguishing composite sheet comprises at least two layers, namely a fire extinguishing layer and a polyurethane continuous phase layer, the fire extinguishing layer is located on at least one surface of the polyurethane continuous phase layer, and is a layer in the flame retardant and fire extinguishing composite sheet containing fire extinguishing medium particles;

[0014] The fire extinguishing layer further includes:

[0015] A floating layer, i.e., a discrete portion of the extinguishing medium particles protruding from the surface of the polyurethane flame retardant substrate; and

[0016] The embedded layer is the portion corresponding to the deepest position of the polyurethane flame retardant substrate where 99% of the fire extinguishing medium particles are embedded based on the number of fire extinguishing medium particles;

[0017] The polyurethane continuous phase layer is a layer that basically does not contain fire extinguishing medium particles; "basically does not contain" means that in this layer, based on the number of fire extinguishing medium particles, only 1% of the fire extinguishing medium particles exist, and the rest are polyurethane flame retardant substrate continuous phase layers.

[0018] In the flame retardant and fire extinguishing composite sheet of the present invention, the floating rate fn of the fire extinguishing medium particles is 0.25-0.8, preferably 0.4-0.7, and the floating rate fn is defined as: fn=H1 / L;

[0019] Where H1 is the thickness of the floating layer, that is, the average protrusion height of the fire extinguishing medium particles protruding from the surface of the polyurethane flame retardant substrate;

[0020] L is the average polar length of the fire extinguishing medium particles, that is, the longest distance between the two intersection points of the line segment passing through the centroid and the edge of the cutting surface on all cutting surfaces when the centroid of the fire extinguishing medium particles is cut at any angle.

[0021] In some of the solutions, the thickness H1 of the floating layer is 0.5-1.5 mm, preferably 0.8-1.2 mm; the thickness H2 of the embedded layer is 0.4-3 mm, preferably 0.6-2.5 mm; the thickness H3 of the polyurethane continuous phase layer is 0.6-5 mm, preferably 1-4 mm.

[0022] In some of the schemes, the fire extinguishing medium particles are one or more particles or granular capsules that can quickly extinguish fire after encountering open flames, splashing flames, or air waves carrying flames. The fire extinguishing medium particles extinguish fires in the following ways: expanding their own volume to isolate the air, quickly releasing high-density non-flammable gas that isolates the flame, and extracting air. One or more methods.

[0023] In some of the schemes, the fire extinguishing medium particles are granular, plate-shaped, columnar or irregularly shaped, preferably spindle-shaped or elliptical particles, and the average polar length L of the fire extinguishing medium particles satisfies 0.5mm≤L≤3mm, preferably satisfies 0.6mm≤L≤2mm, and further preferably satisfies 0.8mm≤L≤1.5mm.

[0024] In some of the schemes, in the polyurethane flame retardant and fire extinguishing composite sheet, the polyurethane is a two-component polyurethane, which is formed by the reaction of a raw material system A and a raw material system B to form a carbamate polymer, wherein the raw material system A includes a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant; and the raw material system B is a polyisocyanate.

[0025] In some of the schemes, the polyisocyanate is listed as: alicyclic isocyanates such as dicyclohexylmethane diisocyanate, aromatic isocyanates such as 5-naphthalene diisocyanate (NDI), 4,4-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), 1-triphenylmethane triisocyanate, xylene diisocyanate (XDI), aliphatic isocyanates such as isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), polymethylene polyphenyl polyisocyanate (PAPI) or prepolymers formed by polymerization of these polyisocyanates with polyols, small molecule chain extenders, etc., or polyisocyanates modified by carbodiimide and mixtures of the above multiple polyisocyanates, and the functionality of the polyisocyanate is in the range of 2-2.8.

[0026] In some of the schemes, the polyol composition can be listed as polyether polyols such as polyoxypropylene polyol, polyoxypropylene-ethylene oxide copolyol, polytrimethylene ether glycol, polytetrahydrofuran and its copolyol, polyester polyols such as polycaprolactone diol, polycaprolactone triol, dimer polyester diol, polymer polyol, polyether polyester polyol, etc. The functionality of the polyol is in the range of 2-4.5, the molecular weight distribution range is 400-12000, and the preferred molecular weight distribution range is 500-6000.

[0027] In some of the schemes, the viscosity range of the raw material system A is 200cps≤η≤15000cps, and the preferred viscosity range is 400cps≤η≤10000cps; the viscosity range of the raw material system B is 10cps≤η≤3000cps, and the preferred viscosity range is 20cps≤η≤2000cps; the viscosity range of the raw material system A and the raw material system B after mixing is guaranteed to be 300cps≤η≤10000cps; the preferred viscosity range is 500cps≤η≤7500cps.

[0028] In some of the schemes, the polyurethane flame retardant and fire extinguishing composite sheet further includes a substrate layer on the other side of the polyurethane continuous phase layer, the thickness H4 of the substrate layer is 0.03-0.25 mm, and the substrate layer is composed of one or more of polyethylene terephthalate film, polycarbonate film, thermoplastic polyurethane composite PET film, glass fiber cloth, polarized non-woven fabric, graphite sheet film, mica paper, and conductive cloth.

[0029] In some of the solutions, the polyurethane flame retardant and fire extinguishing composite sheet may further include an encapsulation layer, which is located on the outermost side of the polyurethane flame retardant and fire extinguishing composite sheet and has a thickness H5 of 0.01-0.02 mm.

[0030] In some of the schemes, the polyurethane flame retardant and fire extinguishing composite sheet can also be provided with one or more of the following layers according to the functional settings: adhesive layer, release layer, anti-slip layer, antibacterial layer, waterproof layer, silent layer and / or electromagnetic shielding layer.

[0031] In some of the schemes, the tensile strength of the polyurethane flame retardant and fire extinguishing composite sheet is 0.5-10 MPa, preferably 1-8 MPa; the tear strength of the polyurethane flame retardant and fire extinguishing composite sheet is 5-60 KN / m, preferably 10-50 KN / m.

[0032] In some of the schemes, the polyurethane flame retardant and fire extinguishing composite sheet is in the form of a coil, a tube or a laminated sheet, preferably a coil.

[0033] In a second aspect, the present invention discloses a method for preparing the polyurethane flame retardant and fire extinguishing composite sheet, the preparation method comprising:

[0034] a. The fire extinguishing medium particles are attached to the surface of the polyurethane resin matrix mixture, and the viscosity of the polyurethane resin matrix mixture is adjusted to be in the range of 300cps≤η≤10000cps; the preferred viscosity range is 500cps≤η≤7500cps;

[0035] b. Then the polyurethane resin mixture is cured in two temperature zones, wherein the temperature range of the low temperature zone is 70-100°C, the temperature range of the high temperature zone is 100-130°C, the speed range of the transport crawler vehicle is 3-10m / min, preferably 5-8m / min, and the curing time of each part of the polyurethane resin mixture in the low temperature zone is 1.5-3min, and the curing time in the high temperature zone is 1.5-3min.

[0036] In some of the schemes, the polyurethane resin mixture is prepared by the following method:

[0037] Select a raw material system A, including a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant, add them into a batching tank in order, stir at a speed of 300-1000 rpm, and the stirring time is 20-120 minutes;

[0038] The stirred raw material system A and the raw material system B are mixed at a high speed of 300-6000 rpm according to the ratio, and after being mixed evenly, they are discharged from the cavity connected to the mixing head, and the distance of the cavity slit is controlled to make the discharge thickness 0.2-6 mm, preferably 0.5-5 mm, to obtain the polyurethane resin mixture;

[0039] The B material raw material system is polyisocyanate.

[0040] In some of the schemes, the fire extinguishing medium particles are attached to the surface of the polyurethane resin matrix resin by the following methods: spreading method, spraying method, gravure coating method, comma coating method, dip coating method, curtain coating method, spin coating method, sponge roller method, die coating method, and brush coating method, among which spreading method is preferred.

[0041] In some of the solutions, the specific steps of attaching the fire extinguishing medium particles to the surface of the polyurethane resin matrix resin mixture by spreading are:

[0042] a1: pre-treat the fire extinguishing medium particles, stir the fire extinguishing medium particles at a high speed of 200-800 rpm, preferably 300-500 rpm, and then perform a drying process at a temperature of 55-80°C for 5-20 hours;

[0043] a2: Control the discharge amount of fire extinguishing medium particles and spread them evenly on the surface of the mixture through a spreader, and the mixture is transported in the TD direction;

[0044] a3: During the transportation process, the surface of the mixture is swept and air-blown for attachment and reinforcement.

[0045] In some of the schemes, the spray is evenly sprayed into the extinguishing medium particles during the high-speed stirring of the extinguishing medium particles, and the stirring and spraying time is 2-8 minutes, so that the extinguishing medium particles are better dispersed;

[0046] In some of the schemes, the surface is purged at a pressure of 0.4-2.5 kg / m 2 ;

[0047] In some of the schemes, the method for preparing the polyurethane flame retardant and fire extinguishing composite sheet further comprises:

[0048] After the polyurethane resin mixture is cured in step cb, encapsulation is performed on the surface of the cured material to obtain an encapsulation layer, and the encapsulation is covered on the surface of the cured material by spraying or atomizing.

[0049] In some embodiments, the polyurethane resin mixture is discharged onto the substrate layer.

[0050] In a third aspect, the polyurethane flame retardant and fire extinguishing composite sheet of the present invention is used for flame retardant and fireproof applications in the battery field. The polyurethane flame retardant and fire extinguishing composite sheet is laid on a battery pack or a battery module to form a flame retardant and fire extinguishing functional layer of the battery.

[0051] Beneficial effects of the present invention:

[0052] The present invention controls the floating state of fire extinguishing medium particles in the polyurethane flame retardant and fire extinguishing composite sheet material, thereby achieving good processing performance of the material in the case of containing the flame retardant and fire extinguishing medium.

[0053] Specifically, by selecting the polar length of the fire extinguishing medium particles themselves and controlling the viscosity and curing conditions of the polyurethane flame retardant substrate itself, the floating state of the fire extinguishing medium particles in the polyurethane flame retardant fire extinguishing composite sheet is achieved, which is reflected by the limitation of the floating rate (fn).

[0054] Such limitations ensure that the material has excellent mechanical and processing properties while maintaining excellent flame retardant and fire extinguishing properties. At the same time, the finished product has excellent toughness and tensile properties, which enables the material to meet the requirements of flatness and interface followability during the paving process, effectively avoiding the problem of easy tearing of the material under tension conditions.

[0055] At the same time, by controlling the floating rate (fn) of the fire extinguishing medium particles, it also reflects the effective distribution of the fire extinguishing medium particles in the polyurethane flame retardant fire extinguishing composite sheet. When encountering a fire, the fire extinguishing medium particles are mainly attached to the surface of the polyurethane flame retardant fire extinguishing composite sheet and are evenly distributed. Therefore, it can respond quickly within the entire composite sheet and has a high fire extinguishing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a schematic cross-sectional view of a polyurethane flame retardant and fire extinguishing composite sheet (excluding a substrate layer and a functional layer);

[0057] Figure 2 It is a schematic cross-sectional view of a polyurethane flame retardant and fire extinguishing composite sheet (including a substrate layer and a functional layer and a double-sided fire extinguishing layer);

[0058] Figure 3 It is a schematic cross-sectional view of a polyurethane flame retardant and fire extinguishing composite sheet (without a substrate layer and a functional layer and having a double-sided fire extinguishing layer);

[0059] Figure 4 It is a top view schematic diagram of a polyurethane flame retardant and fire extinguishing composite sheet (excluding a substrate layer and a functional layer);

[0060] Figure 5 This is a top view of the polyurethane flame retardant and fire extinguishing composite sheet.

[0061] Among them, 1-fire extinguishing layer; 11-floating layer; 12-embedded layer; 2-polyurethane continuous phase layer; 3-fire extinguishing medium particles; 4-polyurethane flame retardant substrate; 5-backing layer; 6-adhesive layer; 7-waterproof layer; 8-electromagnetic shielding layer; 9-packaging layer. DETAILED DESCRIPTION

[0062] Although the present invention has been described to a certain extent, it is obvious that appropriate changes in various conditions can be made without departing from the spirit and scope of the present invention. It is understood that the present invention is not limited to the embodiments described, but belongs to the scope of the claims, which includes equivalent replacements of each factor described.

[0063] Figure 1 The cross-sectional schematic diagram of the polyurethane flame retardant fire extinguishing composite sheet (excluding the substrate layer and the functional layer) shown in the present invention, the polyurethane flame retardant fire extinguishing composite sheet comprises at least two layers, namely a fire extinguishing layer 1 and a polyurethane continuous phase layer 2, the fire extinguishing layer 1 is located on at least one surface of the polyurethane continuous phase layer 2, and is a layer containing fire extinguishing medium particles in the flame retardant fire extinguishing composite sheet; according to the positional relationship between the fire extinguishing medium particles 3 in the fire extinguishing layer 1 and the polyurethane flame retardant substrate 4, the fire extinguishing layer 1 can be further divided into a floating layer 11 and an embedded layer 12, that is, the discrete part of the fire extinguishing medium particles protruding from the continuous polyurethane phase, that is, the floating layer 11 only has the fire extinguishing medium particles protruding from the surface of the continuous polyurethane phase; and the embedded layer 12 is defined as the part corresponding to the deepest position of the continuous polyurethane phase at which 99% of the fire extinguishing medium particles are embedded based on the number of fire extinguishing medium particles, so there are fire extinguishing medium particles 3 and polyurethane flame retardant substrate 4 in the embedded layer 12; the fire extinguishing layer 1 defined by the floating layer 11 and the embedded layer 12 covers 99% of the fire extinguishing medium particles falling into the layer as a whole.

[0064] The polyurethane continuous phase layer 2 is a layer that basically does not contain fire extinguishing medium particles; basically does not contain means that based on the number of fire extinguishing medium particles, only 1% of the fire extinguishing medium particles exist, and the rest are polyurethane flame retardant substrate continuous phase layers, that is, the polyurethane continuous phase layer 2 is mainly composed of polyurethane flame retardant substrate 4 and a few almost negligible end portions of fire extinguishing medium particles 3. It should be noted that the separation plane between the layers in the present invention is parallel to the overall horizontal plane of the polyurethane flame retardant fire extinguishing composite sheet, such as Figure 1-Figure 3 The dividing reference lines shown in are the dividing surfaces between the layers.

[0065] In the flame retardant and fire extinguishing composite sheet of the present invention, the floating rate fn of the fire extinguishing medium particles is 0.25-0.8, preferably 0.4-0.7, and the floating rate fn is defined as: fn=H1 / L;

[0066] Where H1 is the thickness of the floating layer, which is defined as the average protrusion height of the extinguishing medium particles from the surface of the continuous polyurethane phase;

[0067] L is the average polar length of the fire extinguishing medium particles, that is, the longest distance between the two intersection points of the line segment passing through the centroid and the edge of the cutting surface on all cutting surfaces when the centroid of the fire extinguishing medium particles is cut at any angle.

[0068] The floating rate fn reflects the wavy and uneven state of the surface of the polyurethane flame retardant fire extinguishing composite sheet after the fire extinguishing medium particles 3 are embedded in the polyurethane flame retardant substrate 4 to form a sheet structure, so it can reflect the depth and angle of the fire extinguishing medium particles 3 of a specified size embedded in the polyurethane flame retardant substrate 4, and comprehensively and condensely reflects the positional relationship between the fire extinguishing medium particles 3 and the polyurethane flame retardant substrate 4. It is surprisingly found that when the floating rate fn of the fire extinguishing medium particles is controlled within the range specified by the present invention, the material can maintain the tensile properties and tear strength of the material while achieving high flame retardancy and fire extinguishing performance. When the floating rate fn is higher than 0.8, the firmness of the fire extinguishing medium particles is poor and it is easy to fall off. When the floating rate fn is lower than 0.2, the fire extinguishing medium particles are deeply embedded in the polyurethane flame retardant substrate, the fire extinguishing effect is poor, and the tensile properties and tear strength of the material are also affected.

[0069] The thickness H1 of the floating layer 11 is 0.5-1.5 mm, preferably 0.8-1.2 mm; when the thickness H1 of the floating layer is less than 0.5 mm, the portion of the fire extinguishing medium particles 3 protruding from the polyurethane flame retardant substrate 4 is small, so the timely fire extinguishing capability is limited; and when the thickness H1 of the floating layer is greater than 1.5 mm, the fire extinguishing medium particles 3 are not embedded firmly in the polyurethane flame retardant substrate 4, which may easily cause the fire extinguishing medium particles 3 to fall off during the material curing, paving or coil processing.

[0070] The thickness H2 of the embedded layer 12 is 0.4-3 mm, preferably 0.6-2.5 mm. The thickness of the embedded layer 12 reflects the depth of the fire extinguishing medium particles 3 embedded in the polyurethane flame retardant substrate 4. If it is too shallow, the firmness is insufficient, and the fire extinguishing medium particles 3 are likely to fall off during material curing, paving or coil processing. If the thickness is too deep, the fire extinguishing efficiency of the fire extinguishing medium particles is not high, and the mechanical properties will also be affected to a certain extent. The thickness of the embedded layer can be measured by means of ultrasonic detection.

[0071] The thickness H3 of the polyurethane continuous phase layer 2 is 0.6-5 mm, preferably 1-4 mm. If the thickness H3 of the polyurethane continuous phase layer 2 is less than 0.6 mm, the tensile strength of the material is poor, and the embedding firmness of the fire extinguishing medium particles is insufficient. If the thickness H3 of the polyurethane continuous phase layer 2 is greater than 5 mm, the weight of the sheet per unit area increases, but the fireproof effect does not substantially increase, the material cost is increased, and the material is not lightweight in the application scenario.

[0072] The fire extinguishing medium particles are one or more particles or granular capsules that can quickly extinguish fire after encountering open flames or splashing flames or air waves carrying flames, wherein the fire extinguishing medium particles extinguish fires in one or more ways: self-volume expansion to isolate air, rapid release of high-density non-combustible gas that isolates flames, and extraction of air. As specific examples of fire extinguishing medium particles, powder fire extinguishing medium particles such as sodium bicarbonate and phosphate, and multifunctional dry powder fire extinguishing medium particles (ABC fire extinguishing agent) suitable for solid, liquid and gas fires can be included. For oil and electrical fires, especially lithium-ion battery fires, sodium bicarbonate dry powder fire extinguishing medium particles (BC fire extinguishing agent) can be used. It is more preferred to use microencapsulated fire extinguishing medium particles, such as perfluorohexanone fire extinguishing agent microcapsules. The usage amount of the fire extinguishing medium particle medium is related to the fire extinguishing performance of the fire extinguishing medium particles, and can be used within the general content range known to those skilled in the art. Taking perfluorohexanone fire extinguishing agent microcapsules as an example, based on 100 parts of the polyurethane resin matrix mixture, the usage range of perfluorohexanone fire extinguishing agent microcapsules is 30-150 parts, preferably 50-100 parts.

[0073] The fire extinguishing medium particles are granular, plate-like, columnar or irregularly shaped, preferably spindle-shaped or elliptical particles, and the average polar length L of the fire extinguishing medium particles satisfies 0.2mm≤L≤3mm, preferably satisfies 0.3mm≤L≤2mm, and further preferably satisfies 0.5mm≤L≤1.5mm.

[0074] According to the many years of research by the inventors of the present invention, some expandable fire extinguishing medium particles and fire extinguishing microcapsules that use hollow capsules to encapsulate fire extinguishing gas (liquid) have shown that the size is positively correlated with the fire extinguishing performance. The possible reason is that when the polar length is larger, the expandable ratio and the thickness of the fire extinguishing microcapsule shell are higher, which can form a container with higher pressure and encapsulate more fire extinguishing liquid. However, the polar length cannot be increased indefinitely. When L>3mm, the particle size is too large, resulting in a decrease in the anchoring ability of the fire extinguishing medium particles on the continuous polyurethane phase and causing them to fall off. During use, for example, in a battery pack or module, if they fall off, it is easy to cause short circuits and other abnormalities. When L<0.3mm, the fire blocking / fire extinguishing ability decreases.

[0075] The polar length is defined as cutting the centroid of the extinguishing medium particle at any angle. The cutting surface must pass through the centroid. Line segments passing through the centroid are made on all cut surfaces. There is a certain distance between the two intersection points of the line segment and the edge of the cutting surface. The longest line segment is called the polar length. The actual measurement method of the polar length can be to disperse the continuous polyurethane phase in a 5% Tween-80 solution at the raw material stage, ultrasonically treat it at room temperature for 30min-1h, and then observe the image with an optical microscope. Then, the image is processed and the long diameter of the continuous polyurethane phase in the image is obtained for statistics and average.

[0076] In the polyurethane flame retardant fire extinguishing composite sheet, the polyurethane is a two-component polyurethane, which is formed by the reaction of the A material raw material system and the B material raw material system to form a carbamate polymer, wherein the A material raw material system includes a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant; the B material raw material system is a polyisocyanate. The catalyst, surfactant, flame retardant, and color paste are all conventional materials in the art. The AB materials are mixed, foamed, and cured to form the polyurethane phase of the present invention.

[0077] The polyisocyanates are listed as: alicyclic isocyanates such as dicyclohexylmethane diisocyanate, aromatic isocyanates such as 5-naphthalene diisocyanate (NDI), 4,4-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), 1-triphenylmethane triisocyanate, xylene diisocyanate (XDI), aliphatic isocyanates such as isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), polymethylene polyphenyl polyisocyanate (PAPI) or prepolymers formed by polymerization of these polyisocyanates with polyols, small molecule chain extenders, etc., or polyisocyanates modified by carbodiimide and mixtures of the above multiple polyisocyanates, and the functionality of the polyisocyanates is in the range of 2-2.8.

[0078] The polyol composition can be listed as polyether polyols such as polyoxypropylene polyol, polyoxypropylene-ethylene oxide copolyol, polytrimethylene ether glycol, polytetrahydrofuran and its copolyol, polyester polyols such as polycaprolactone diol, polycaprolactone triol, dimer polyester diol, polymer polyol, polyether polyester polyol, etc. The functionality of the polyol is in the range of 2-4.5, the molecular weight distribution range is 400-12000, and the preferred molecular weight distribution range is 500-6000.

[0079] The viscosity range of the A material raw material system is 200cps≤η≤15000cps, and the preferred viscosity range is 400cps≤η≤10000cps; the viscosity range of the B material raw material system is 10cps≤η≤3000cps, and the preferred viscosity range is 20cps≤η≤2000cps; after the A material raw material system and the B material raw material system are mixed, the viscosity range is guaranteed to be 300cps≤η≤10000cps; the preferred viscosity range is 500cps≤η≤7500cps. When the viscosity of the combined material η is less than 300cps during assembly, the fire extinguishing medium particles are embedded too deeply due to their own weight and the vibration frequency of the receiving plate, thereby prolonging the fire extinguishing time and reducing the tensile strength and tear strength of the flame retardant and fire extinguishing composite sheet. However, when the viscosity of the combined material is greater than 10000CPs during assembly, the material cannot be embedded even if the vibration frequency is increased, causing the fire extinguishing medium particles to float on the surface, which is prone to the risk of falling off. At the same time, because the fire extinguishing medium particles floating on the surface are not restrained by pressure when heated, they may lose the fire extinguishing effect in a very short time. At the same time, excessive viscosity increases the difficulty of processing.

[0080] The polyurethane flame retardant fire extinguishing composite sheet also includes a substrate layer 5 on the other side of the polyurethane flame retardant substrate layer, and the thickness of the substrate layer 5 is 0.03-0.25mm, and more preferably 0.05mm-0.15mm. The substrate layer 5 is composed of one or more of polyethylene terephthalate film, polycarbonate film, thermoplastic polyurethane composite PET film, glass fiber cloth, polarized non-woven fabric, graphite film, mica paper, and conductive cloth. When the above materials are selected in this thickness range, the polyurethane flame retardant fire extinguishing composite sheet has better cross-sectional tracking on the side where the substrate layer is located. When the thickness of the substrate layer 5 is too low, the flame retardant substrate layer may be deformed due to the MD direction tension in the actual production process, forming ripples, folding lines, etc., and the abnormality formed may cause the pavement of the polyurethane flame retardant fire extinguishing composite sheet to deteriorate due to the cross-sectional tracking. When the thickness of the substrate layer is too large, the cost is too high, and the proportion of the fire extinguishing layer in the polyurethane flame retardant fire extinguishing composite sheet is reduced, and the performance of flame retardant fire extinguishing is often reduced.

[0081] The polyurethane flame retardant fire extinguishing composite sheet may also include an encapsulation layer 9, which is located at the outermost side of the polyurethane flame retardant fire extinguishing composite sheet and has a thickness of 0.01-0.02 mm. The encapsulation layer can further improve the stability of the fire extinguishing material. The encapsulation layer can be formed by coating a polymer film on the surface of the fire extinguishing layer. Spray a specific polymer film on the surface of the fire extinguishing layer to form a protective film coated on the surface of the fire extinguishing layer, which blocks air, moisture, prevents aging, prevents acid and alkali mist, resists ultraviolet rays, maintains appropriate humidity, and has a self-repairing function under certain conditions. The polymer film is selected from one or more of polyesters, polyurethanes, phenolic resins, urea-formaldehyde resins, polyurea resins, polysiloxanes, natural polymers, acrylic resins, and epoxy resins.

[0082] The polyurethane flame retardant and fire extinguishing composite sheet may be further provided with one or more of the following layers according to the functional setting: adhesive layer, release layer, anti-slip layer, antibacterial layer, waterproof layer, mute layer and / or electromagnetic shielding layer. These functional layers may be coated or laminated on the polyurethane flame retardant and fire extinguishing composite sheet of the present invention according to the materials having the above functions in the art.

[0083] The tensile strength of the polyurethane flame retardant fire extinguishing composite sheet is 0.5-10MPa, preferably 1-8MPa; this range is the ideal tensile strength of the polyurethane flame retardant fire extinguishing composite sheet. When it is greater than 10Mpa, the polyurethane flame retardant fire extinguishing composite sheet may be too hard and tough to be easily collected in a winding manner. At the same time, due to the high hardness, the cross-section tracking of the polyurethane flame retardant fire extinguishing composite sheet is poor during construction and installation, and it is easy to be brittle fractured under external pressure conditions, resulting in the inability to construct. When it is less than 0.5MPa, the fire extinguishing medium particles are embedded too deeply, which will further affect the fire extinguishing effect. At the same time, if other layers are composited later, there will be tensile fractures, and when the tensile strain of the material is too low, it is easy to cause plastic deformation under tension conditions.

[0084] The tear strength of the polyurethane flame retardant fire extinguishing composite sheet is 5-60KN / m; preferably 10-50KN / m. This range is the ideal tear strength of the polyurethane flame retardant fire extinguishing composite sheet. When the tear strength is less than 5KN / m, the fire extinguishing medium particles are embedded too deeply, which will further affect the fire extinguishing effect. At the same time, if other layers are subsequently compounded, there will be tensile fractures; when the tear strength is greater than 60KN / m, the fire extinguishing coil may be too hard and tough to be easily collected in a winding manner. At the same time, due to the high hardness, the cross-section tracking of the fire extinguishing coil is poor during the construction and installation process, and it is easy to be brittle fracture under external pressure conditions, resulting in the inability to be constructed.

[0085] The polyurethane flame retardant and fire extinguishing composite sheet is in the form of a coil, a tube or a laminated sheet, preferably a coil.

[0086] The present invention also discloses a method for preparing the polyurethane flame retardant and fire extinguishing composite sheet, the method comprising:

[0087] a. The fire extinguishing medium particles are attached to the surface of the polyurethane resin matrix mixture, and the viscosity of the polyurethane resin mixture is adjusted to be in the range of 300cps≤η≤10000cps; the preferred viscosity range is 500cps≤η≤7500cps;

[0088] b. Then the polyurethane resin mixture is cured in two temperature zones, wherein the temperature range of the low temperature zone is 70-100°C, the temperature range of the high temperature zone is 100-130°C, the speed range of the transport crawler vehicle is 3-10m / min, preferably 5-8m / min, and the curing time of each part of the polyurethane resin mixture in the low temperature zone is 1.5-3min, and the curing time in the high temperature zone is 1.5-3min.

[0089] The curing time of the low temperature zone and the high temperature zone is set to ensure production efficiency and prevent the fire extinguishing medium particles from staying in the oven section for too long, resulting in premature demise and affecting efficiency. At the same time, the curing rate of the polyurethane resin prepolymer needs to be ensured. The temperature of the front zone is controlled to be above 70°C to ensure that the flame retardant substrate layer can be better cured within the said curing time, and at the same time, the curing rate of the material is controlled so that the fire extinguishing medium particles are not embedded too quickly. At the same time, the low temperature zone also avoids excessive energy consumption during the entire curing process. The high temperature section is set at 100°C-130°C to improve the curing efficiency of the polyurethane resin and avoid premature decomposition of the fire extinguishing medium particles. In short, the control of the zone temperature is to control the curing rate of the material to adjust the embedding state of the fire extinguishing medium particles, and at the same time ensure that the fire extinguishing medium particles are not destroyed prematurely.

[0090] The polyurethane resin mixture is prepared by the following method:

[0091] Select a raw material system A, including a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant, add them into a batching tank in order, stir at a speed of 300-1000 rpm, and the stirring time is 20-120 minutes;

[0092] The stirred raw material system A and the raw material system B are mixed at a high speed of 300-6000 rpm according to the ratio, and after being mixed evenly, they are discharged from the cavity connected to the mixing head, and the distance of the cavity slit is controlled to make the discharge thickness 0.2-6 mm, preferably 0.5-5 mm, to obtain the polyurethane resin mixture;

[0093] The B material raw material system is polyisocyanate.

[0094] The fire extinguishing medium particles are attached to the surface of the polyurethane resin matrix resin by the following methods: spreading method, spraying method, gravure coating method, comma coating method, dip coating method, curtain coating method, spin coating method, sponge roller method, die coating method, brush coating method, among which spreading method is preferred.

[0095] The specific steps of attaching the fire extinguishing medium particles to the surface of the polyurethane resin matrix resin mixture by spreading method are as follows:

[0096] a1: pre-treat the fire extinguishing medium particles, stir the fire extinguishing medium particles at a high speed of 200-800 rpm, preferably 300-500 rpm, and then perform a drying process at a temperature of 55-80°C for 5-20 hours;

[0097] a2: Control the discharge amount of fire extinguishing medium particles and spread them evenly on the surface of the mixture through a spreader, and the mixture is transported in the TD direction;

[0098] a3: During the transportation process, the surface of the mixture is swept and air-blown for attachment and reinforcement.

[0099] It is further preferred that the spray is evenly sprayed on the fire extinguishing medium particles during high-speed stirring, and the stirring and spraying time is 2-8 minutes. This can make the fire extinguishing medium particles more evenly distributed on the surface of the polyurethane resin matrix resin.

[0100] The spreading machine consists of two major parts: a feeding machine and a vibrating belt conveyor.

[0101] Among them, the blanking machine includes:

[0102] The weighing system is used to monitor the discharge amount and work in conjunction with the screw of the conveying system to adjust and complete the predetermined fixed delivery amount; the transverse movement system uses reciprocating transverse movement to make the material fall evenly within a lateral range when the conveying system discharges the material into the slit. Specifically, this range is 0.5 meters to 2 meters to meet the width requirements under different production conditions; the conveying system adopts a screw structure to adjust the discharge amount of the fire extinguishing medium particles to meet different spreading requirements; the slit has a certain width, and its length and transverse movement width can be adjusted according to the actual production width to ensure uniform distribution of the material.

[0103] The vibrating belt conveyor includes:

[0104] The frame is used to support and form the frame structure of the conveyor. The transmission device, as the main transportation device, is responsible for the continuous transportation of materials. The closed belt is the main carrier of the materials and realizes the continuous transportation of materials through a closed structure. The vibrator mainly adjusts the vibration frequency to achieve uniform dispersion and flattening of materials, and has a certain transportation capacity.

[0105] The specific working principle is as follows: first, the material discharge flow rate is set, and the weighing system is linked to the screw conveyor to adjust the discharge amount, so that the material enters the slit with a fixed weight and falls onto the closed ring belt of the vibrating belt conveyor. The material on the ring belt is further spread evenly under the action of the exciter, and through the forward vibration force and the transmission of the transmission device, the fire extinguishing medium particles are evenly spread in the TD direction of the polyurethane flame retardant fire extinguishing composite sheet.

[0106] In order to ensure the strength of the purge, the air pressure on the surface is controlled to be 0.4-2.5kg / m 2 ,Within this range, the embedding of fire extinguishing medium particles in the surface of polyurethane resin matrix resin is moderate, which is one of the factors affecting the floating rate.

[0107] The method for preparing the polyurethane flame retardant and fire extinguishing composite sheet also includes:

[0108] After the polyurethane resin mixture is cured in step cb, encapsulation is performed on the surface of the cured material to obtain an encapsulation layer, and the encapsulation is covered on the surface of the cured material by spraying or atomizing.

[0109] Taking the spraying step of the encapsulation layer as an example, it specifically includes mixing the encapsulation liquid evenly, and then spraying it evenly onto the already cured combination A / B material through a spray device to encapsulate the semi-finished product, and then performing thermal curing or UV curing. The thermal curing process is drying and curing at 90-120℃ for 3-10 minutes, and the UV curing uses mercury lamp or LED irradiation, the irradiation wavelength range is 365±50nm, and the curing time is 2-3 minutes.

[0110] When the substrate layer is present, the polyurethane resin mixture is supported on the substrate layer.

[0111] Finally, the formed layers are laminated and compacted, and the desired products are obtained by slitting. If coils are required, there is also a winding step.

[0112] The polyurethane flame retardant and fire extinguishing composite sheet of the present invention is used for flame retardant and fireproofing in the battery field. The polyurethane flame retardant and fire extinguishing composite sheet is paved on a battery pack or a battery module to form a flame retardant and fire extinguishing functional layer of the battery.

[0113] Hereinafter, the present invention will be described by referring to several embodiments, but the present invention is not intended to be limited to these embodiments.

[0114] Embodiment 1:

[0115] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0116] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0117] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0118] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0119] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0120] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0121] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0122] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0123] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0124] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0125] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0126] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0127] The viscosity of the material A composition after mixing is 3400 cps.

[0128] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0129] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0130] Embodiment 2:

[0131] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0132] Isocyanate 3# (NCO% value 10.3%, viscosity 500cps, functionality 2) content 11.45 parts;

[0133] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 2.86 parts; the viscosity of the B material composition after mixing is 600 cps.

[0134] A material composition:

[0135] Polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 8.55 parts;

[0136] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 2.85 parts;

[0137] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 5.70) content 6.90 parts;

[0138] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 22.80 parts;

[0139] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 16.53 parts;

[0140] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.17 parts;

[0141] Surfactant (Tween) 0.57 parts;

[0142] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 22.80 parts

[0143] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 5.7 parts

[0144] The viscosity of the material A composition after mixing was 11890 cps.

[0145] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 9624 cps.

[0146] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 3m / min. The temperature in the low temperature zone of the heat curing area is 70℃, the curing time is 3min, and the temperature in the high temperature zone is 125℃, and the curing time is 2min.

[0147] Embodiment 3:

[0148] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0149] Material B composition: 12.20 parts of isocyanate 4# (NCO% value 25%, viscosity 150 cps, functionality 2). The viscosity of the material B composition after mixing is 150 cps.

[0150] A material composition:

[0151] Polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 14.01 parts;

[0152] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.50 parts;

[0153] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 7.01 parts;

[0154] Polyol 4 (brand 560D, hydroxyl value 56, viscosity 500, functionality 3) content 28.03 parts;

[0155] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.32 parts;

[0156] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0157] Surfactant (silicone oil, brand 4004) content 0.7 parts;

[0158] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 1.40 parts;

[0159] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 12.61 parts;

[0160] The viscosity of the material A composition after mixing was 534.15 cps.

[0161] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 477 cps.

[0162] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 8m / min. The temperature in the low temperature zone of the heat curing area is 95℃, the curing time is 1.5min, and the temperature in the high temperature zone is 110℃, and the curing time is 2.5min.

[0163] Embodiment 4:

[0164] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0165] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0166] Isocyanate 2# (NCO% value 17%, viscosity 1000cps, functionality 2.5) content 6.78 parts;

[0167] The viscosity of the material B composition after mixing is 850 cps.

[0168] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0169] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0170] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0171] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0172] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0173] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0174] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0175] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0176] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0177] The viscosity of the material A composition after mixing is 3400 cps.

[0178] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0179] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 3 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0180] Embodiment 5:

[0181] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0182] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0183] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0184] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0185] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0186] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0187] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0188] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0189] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0190] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0191] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0192] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0193] The viscosity of the material A composition after mixing is 3400 cps.

[0194] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0195] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 10m / min. The temperature of the low temperature zone of the heat curing area is 70℃, the curing time is 3min, and the temperature of the high temperature zone is 130℃, and the curing time is 2min.

[0196] Embodiment 6:

[0197] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0198] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0199] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0200] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0201] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0202] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0203] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0204] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0205] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0206] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0207] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0208] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0209] The viscosity of the material A composition after mixing is 3400 cps.

[0210] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0211] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0212] The polyurethane resin formed by heat curing is encapsulated using an acrylic polymer, and the thickness of the encapsulation layer is 0.1 mm.

[0213] Embodiment 7:

[0214] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0215] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0216] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0217] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0218] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0219] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0220] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0221] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0222] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0223] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0224] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0225] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0226] The viscosity of the material A composition after mixing is 3400 cps.

[0227] The material A and the material B composition are mixed to form a polyurethane resin mixture, the viscosity of which after mixing is 2897 cps, and it is discharged onto a polyethylene terephthalate substrate, and the thickness of the substrate layer is 0.03 mm.

[0228] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2, it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0229] The polyurethane resin formed by heat curing is encapsulated using an acrylic polymer, and the thickness of the encapsulation layer is 0.1 mm.

[0230] Comparative Example 1:

[0231] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0232] Material B composition: Isocyanate 3# (NCO% value 10.3%, viscosity 500cps, functionality 2) content 7.84 parts

[0233] The content of isocyanate 2# (NCO% value 17%, viscosity 1000cps, functionality 2.5) is 5.22 parts; the viscosity of the B material composition after mixing is 700cps.

[0234] Material A composition: Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 2.87 parts;

[0235] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 5.75 parts;

[0236] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 22.99 parts;

[0237] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 17.24 parts;

[0238] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.17 parts;

[0239] Surfactant (silicone oil, brand 4004) content 0.57 parts;

[0240] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 28.73 parts;

[0241] The viscosity of the material A composition after mixing is 17000 cps.

[0242] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 13981 cps.

[0243] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0244] Comparative Example 2:

[0245] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0246] Material B composition: 9.92 parts of isocyanate 4# (NCO% value 25%, viscosity 150 cps, functionality 2); the viscosity of the material B composition after mixing is 150 cps.

[0247] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 11.14 parts;

[0248] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.71 parts;

[0249] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 7.43 parts;

[0250] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 51.98 parts;

[0251] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.22 parts;

[0252] Surfactant (silicone oil, brand 4004) content 0.74 parts;

[0253] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 1.49 parts;

[0254] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 13.37 parts;

[0255] The viscosity of the material A composition after mixing was 305.25 cps.

[0256] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 287 cps.

[0257] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0258] Comparative Example 3:

[0259] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0260] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0261] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0262] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0263] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0264] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0265] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0266] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0267] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0268] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0269] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0270] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0271] The viscosity of the material A composition after mixing is 3400 cps.

[0272] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0273] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 3.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0274] Comparative Example 4:

[0275] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0276] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0277] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0278] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0279] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0280] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0281] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0282] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0283] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0284] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0285] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0286] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0287] The viscosity of the material A composition after mixing is 3400 cps.

[0288] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0289] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 0.2 mmd were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the low temperature zone of the heat curing area is 85℃, the curing time is 2min, and the temperature in the high temperature zone is 115℃, and the curing time is 2min.

[0290] Comparative Example 5:

[0291] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0292] Material B composition: 10.18 parts of isocyanate 1# (NCO% value 8.5%, viscosity 750cps, functionality 2);

[0293] The content of isocyanate 2# (NCO% value 17%, viscosity 1000 cps, functionality 2.5) is 6.78 parts; the viscosity of the B material composition after mixing is 850 cps.

[0294] Material A composition: polyol 1 (brand DL-1000D, hydroxyl value 110, viscosity 170 cps, functionality 2) content 10.35 parts;

[0295] Polyol 2 (brand name Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 3.45 parts;

[0296] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 6.90 parts;

[0297] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 27.61 parts;

[0298] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 20.02 parts;

[0299] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.21 parts;

[0300] Surfactant (silicone oil, brand 4004) content 0.69 parts;

[0301] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 2.76 parts;

[0302] Flame retardant 2 (alkyl phosphate, brand YK-6HF) content 11.04 parts;

[0303] The viscosity of the material A composition after mixing is 3400 cps.

[0304] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 2897 cps.

[0305] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 1.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 6m / min. The temperature in the heat curing area is uniformly set at 60°C, and the curing time is 3min.

[0306] Comparative Example 6:

[0307] The polyurethane resin matrix mixture is formed according to the following formula, wherein the total number of parts of the formula is 100 parts:

[0308] Material B composition: Isocyanate 3# (NCO% value 10.3%, viscosity 500cps, functionality 2) content 7.84 parts

[0309] The content of isocyanate 2# (NCO% value 17%, viscosity 1000cps, functionality 2.5) is 5.22 parts; the viscosity of the B material composition after mixing is 700cps.

[0310] Material A composition: Voranol TM 4000LM, hydroxyl value 28, viscosity 1000, functionality 2) content 2.87 parts;

[0311] Polyol 3 (brand name CHE-628, hydroxyl value 22, viscosity 1500cps, functionality 6) content 5.75 parts;

[0312] Polyol 4 (brand name LPOP-H45, hydroxyl value 22, viscosity 5000, functionality 3) content 22.99 parts;

[0313] Polyol 5 (brand NJ-330E, hydroxyl value 35, viscosity 550, functionality 3) content 17.24 parts;

[0314] Catalyst 1 (organic metal catalyst, grade DABCO 8154) content 0.17 parts;

[0315] Surfactant (silicone oil, brand 4004) content 0.57 parts;

[0316] Flame retardant 1 (aluminum hydroxide, brand JZ-1000DN), content 28.73 parts;

[0317] The viscosity of the material A composition after mixing is 17000 cps.

[0318] The material A and the material B are mixed to form a polyurethane resin mixture, and the viscosity after mixing is 13981 cps.

[0319] 80 parts of perfluorohexanone fire extinguishing microcapsules with an average polar length L of 3.5 mm were attached to the surface of the polyurethane resin mixture and purged at a purging pressure of 1.2 kg / m 2 , it is transported to the heat curing area in the TD direction at a speed of 2m / min. The temperature in the heat curing area is uniformly set at 80°C, and the curing time is 8min.

[0320] Test method:

[0321] 1. <Flame extinguishing properties>

[0322] Test method:

[0323] The test device uses a UL94 combustion test box, and uses a combustion gas of more than 98% purity methane gas. The test environment is 23±2℃ and the relative humidity is 55±10%RH. The gas passes through a copper tube with a length of 100±10mm and an inner diameter of 9.5±0.3mm. The copper tube has an inclination angle of 45℃. By adjusting the flow of combustible gas and air, the flame tip is made to be greater than 1cm in length and presents a blue flame. The total height of the flame is 2cm. The sample is cut into a square piece of 50mm*50mm, and the four corners of the test piece are fixed on a steel mesh (the steel mesh is a mesh structure with a side length of 6.4±0.4mm woven from steel wire with a diameter of 0.88±0.1mm). The thickness direction of the sample is perpendicular to the steel mesh and the combustion gas conduit. The floating layer of the sample faces the flame direction, and one side of the sample is perpendicular to the combustion gas conduit. The top edge of the sample is 3.5cm higher than the combustion gas conduit, and the initial distance of the sample floating layer is at least >5cm. At the same time, the sample approaches the flame at a rate of 25mm / min. The timing starts at 1cm away from the flame. At the same time, the sample continues to approach the flame. When it is completely close to the flame, it stops approaching and then records the flame extinguishing time. The recorded time <20s is recorded as excellent flame extinguishing performance, 20-24s is recorded as good, 24-40s and above are recorded as fair, and more than 40s are recorded as poor.

[0324] 2. Tear strength

[0325] Tested according to GB / T 40872-2021.

[0326] 3. Tensile strength

[0327] Tested according to GB / T 40872-2021.

[0328] 4. Firmness

[0329] Take a test piece with a width of 70mm and a length of 300mm from each of the vertical and horizontal directions, add a urethane foam with a width of 70mm, a length of 300mm and a thickness of 10mm on the back, and fix it on the plane wear tester T-TYPE (manufactured by Daiei Kagaku Seiki Manufacturing Co., Ltd.). Apply a load of 9.8N to the friction block covered with cotton cloth (cotton canvas) to wear the test piece. The friction block is reciprocated 10,000 times at a speed of 60 back and forth / minute within 140mm on the surface of the test piece. (Cotton canvas: The cotton canvas is replaced every 2,500 reciprocating frictions, and the total reciprocating wear is 10,000 times). Observe the test piece after wear and make judgments according to the following criteria.

[0330] Level 5: No change in appearance (no cracks or damage)

[0331] Level 4: Slight wear and tear, not noticeable

[0332] Level 3: Obvious wear and tear is observed, and the base material layer is exposed (cracks appear)

[0333] The exposure of the second-level base material layer is slightly obvious

[0334] The first-level base material layer is exposed significantly (damage is seen)

[0335] The structural characteristics and performance parameters of Examples 1-7 and Comparative Examples 1-6 are shown in Table 1 and Table 2:

[0336] Table 1: Structural parameters of Examples 1-7 and Comparative Examples 1-6

[0337]

[0338] Table 2: Performance indicators of Examples 1-7 and Comparative Examples 1-6

[0339]

[0340] It can be seen from the above embodiments and comparative examples that when the polyurethane flame retardant and fire extinguishing composite sheet satisfies the floating rate range of 0.25-0.8, while achieving high flame retardancy and fire extinguishing performance, it can maintain the tensile properties and tear strength of the material. The control of the floating rate depends on the viscosity of the polyurethane resin mixture, the polar length of the fire extinguishing medium particles, the curing temperature control and the curing time. No matter how these factors change, it can be found that when the floating rate is ensured to fall within the range, the polyurethane flame retardant and fire extinguishing composite sheet can achieve high flame retardancy and fire extinguishing performance, and ensure ideal mechanical strength.

Claims

1. A polyurethane flame retardant and fire extinguishing composite sheet, characterized in that: The flame retardant and fire extinguishing composite sheet comprises at least two layers, namely a fire extinguishing layer and a polyurethane continuous phase layer. The fire extinguishing layer is located on at least one surface of the polyurethane continuous phase layer and is a layer in the flame retardant and fire extinguishing composite sheet containing fire extinguishing medium particles. The fire extinguishing layer further comprises: A floating layer, i.e., a discrete portion of the extinguishing medium particles protruding from the surface of the polyurethane flame retardant substrate; and The embedded layer is the portion corresponding to the deepest position of the polyurethane flame retardant substrate where 99% of the fire extinguishing medium particles are embedded based on the number of fire extinguishing medium particles; The polyurethane continuous phase layer is a layer that substantially does not contain fire extinguishing medium particles; "Substantially free of" means that in the layer, based on the number of fire extinguishing medium particles, only a portion of 1% of the fire extinguishing medium particles exist, and the rest are layers of the continuous phase of the polyurethane flame retardant substrate; The floating rate fn of the fire extinguishing medium particles in the polyurethane flame retardant fire extinguishing composite sheet is 0.25-0.8, and the floating rate fn is defined as: fn=H1 / L; Where H1 is the thickness of the floating layer, that is, the average protrusion height of the fire extinguishing medium particles protruding from the surface of the polyurethane flame retardant substrate; L is the average polar length of the fire extinguishing medium particles, that is, the longest distance between the two intersection points of the line segment passing through the centroid and the edge of the cutting surface on all cutting surfaces when the centroid of the fire extinguishing medium particles is cut at any angle.

2. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The thickness H1 of the floating layer is 0.5-1.5 mm; the thickness H2 of the embedded layer is 0.4-3 mm; and the thickness H3 of the polyurethane continuous phase layer is 0.6-5 mm.

3. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The fire extinguishing medium particles are one or more particles or granular capsules that can quickly extinguish fire after encountering open flames, splashing flames, or air waves carrying flames. The fire extinguishing medium particles extinguish fire in one or more ways: expanding their own volume to isolate the air, quickly releasing high-density non-flammable gas that isolates the flame, and extracting air.

4. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The fire extinguishing medium particles are granular, plate-like, columnar or irregular in shape, and the average polar length L of the fire extinguishing medium particles satisfies 0.5 mm ≤ L ≤ 3 mm.

5. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: In the polyurethane flame retardant and fire extinguishing composite sheet, the polyurethane is a two-component polyurethane, which is formed by the reaction of a raw material system A and a raw material system B to form a carbamate polymer, wherein the raw material system A includes a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant; the raw material system B is a polyisocyanate; The polyisocyanate is: dicyclohexylmethane diisocyanate alicyclic isocyanate, 5-naphthalene diisocyanate (NDI), 4,4-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), 1-triphenylmethane triisocyanate, xylylene diisocyanate (XDI) aromatic isocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI) aliphatic isocyanate, polymethylene polyphenyl polyisocyanate (PAPI) or a prepolymer formed by polymerization of these polyisocyanates with polyols and small molecule chain extenders, or a polyisocyanate modified by carbodiimide and a mixture of the above multiple polyisocyanates, and the functionality of the polyisocyanate is in the range of 2-2.8; and The polyol composition is polyether polyols such as polyoxypropylene polyol, polyoxypropylene-ethylene oxide copolymer polyol, polytrimethylene ether glycol, polytetrahydrofuran and copolymer glycol thereof, polyester polyols such as polycaprolactone diol, polycaprolactone triol, dimer polyester diol, polymer polyol, polyether polyester polyol. The functionality of the polyol is in the range of 2-4.5, and the molecular weight distribution is in the range of 400-12000.

6. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The viscosity range of the raw material system of material A is 200cps≤η≤15000cps; the viscosity range of the raw material system of material B is 10cps≤η≤3000cps; and The viscosity of the raw material system A and the raw material system B after mixing is guaranteed to be in the range of 300cps≤η≤10000cps.

7. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The polyurethane flame retardant fire extinguishing composite sheet further comprises a substrate layer on the other side of the polyurethane continuous phase layer, the thickness H4 of the substrate layer is 0.03-0.25 mm, and the substrate layer is composed of one or more of polyethylene terephthalate film, polycarbonate film, thermoplastic polyurethane composite PET film, glass fiber cloth, polarized non-woven fabric, graphite film, mica paper, and conductive cloth; and / or The polyurethane flame retardant and fire extinguishing composite sheet further comprises a packaging layer, which is located at the outermost side of the polyurethane flame retardant and fire extinguishing composite sheet and has a thickness H5 of 0.01-0.02 mm.

8. The polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The polyurethane flame retardant and fire extinguishing composite sheet is further provided with one or more of the following layers according to the functional setting: an adhesive layer, a release layer, an anti-slip layer, an antibacterial layer, a waterproof layer, a mute layer and / or an electromagnetic shielding layer.

9. A method for preparing the polyurethane flame retardant and fire extinguishing composite sheet according to claim 1, characterized in that: The preparation method comprises: a. The fire extinguishing medium particles are attached to the surface of the polyurethane resin matrix mixture, and the viscosity of the polyurethane resin matrix mixture is adjusted to be in the range of 300cps≤η≤10000cps; b. The polyurethane resin mixture is then cured in two temperature zones, wherein the temperature range of the low temperature zone is 70-100°C, the temperature range of the high temperature zone is 100-130°C, the speed range of the transport crawler vehicle is 3-10m / min, and the curing time of each part of the polyurethane resin mixture in the low temperature zone is 1.5-3min, and the curing time in the high temperature zone is 1.5-3min.

10. The method for preparing the polyurethane flame retardant and fire extinguishing composite sheet according to claim 9, characterized in that: The polyurethane resin mixture is further prepared by the following method: Select a raw material system A, including a group consisting of a polyol composition, a surfactant, a catalyst, a color paste, and a flame retardant, add them into a batching tank in order, stir at a speed of 300-1000 rpm, and the stirring time is 20-120 minutes; The stirred raw material system A and the raw material system B are mixed at a high speed of 300-6000 rpm according to the ratio, and after being mixed evenly, they are discharged from the cavity connected to the mixing head, and the distance of the cavity slit is controlled so that the discharge thickness is 0.2-6 mm to obtain the polyurethane resin mixture; The B material raw material system is polyisocyanate.

11. The method for preparing the polyurethane flame retardant and fire extinguishing composite sheet according to claim 9, characterized in that: The method for preparing the polyurethane flame retardant and fire extinguishing composite sheet also includes: c. After the polyurethane resin mixture in step b is cured, the surface of the cured material is encapsulated to obtain an encapsulation layer, and the encapsulation is covered on the surface of the cured material by spraying or atomizing.

12. The method for preparing the polyurethane flame retardant and fire extinguishing composite sheet according to claim 9, characterized in that: The polyurethane resin mixture is discharged on the substrate layer.

13. The flame retardant and fire extinguishing application of the polyurethane flame retardant and fire extinguishing composite sheet according to claim 1 in the battery field, wherein the polyurethane flame retardant and fire extinguishing composite sheet is laid on a battery pack or a battery module to form a flame retardant and fire extinguishing functional layer of the battery.

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