Continuous fiber reinforced flame-retardant copolymerized nylon sheet as well as preparation method and application thereof

Abstract

The invention discloses a continuous fiber reinforced flame-retardant copolymerized nylon sheet as well as a preparation method and application thereof. The copolymerized nylon sheet is mainly formed by compounding fiber cloth and activated caprolactam in a mass ratio of 1: (0.4-0.8), the activated caprolactam is mainly formed by mixing a component A and a component B and carrying out caprolactam anionic polymerization, the component A comprises caprolactam, a catalyst, a flame retardant and a coupling agent, and the component B comprises caprolactam, an activator, a copolymerization toughening monomer, an antioxidant and a lubricant. The preparation method comprises the following steps: (1) unwinding and preheating fiber cloth; and (2) mixing the component A and the component B, spraying the mixture to the surface of the fiber cloth, and sequentially performing dipping, reaction, curing, solid-phase tackifying, traction calendering, cooling sizing, air cooling and rolling to obtain the fiber cloth. The sheet provided by the invention has high strength, high toughness and flame retardance, and can replace a metal sheet. The method disclosed by the invention can realize continuous reaction forming, is uniform and simple in impregnation, low in cost and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to a copolymer nylon sheet material and a preparation method and application thereof, and in particular to a continuous fiber reinforced flame retardant copolymer nylon sheet material and a preparation method and application thereof. Background Art

[0002] Nylon composite materials have the characteristics of high strength, corrosion resistance, light weight, and recyclability. As an important structural material replacing steel with plastic, they are widely used in the fields of lightweight automobiles and rail transit, lightweight and corrosion protection of large pipelines. In particular, continuous fiber reinforced nylon composite materials have the strength of steel plates and are increasingly favored and valued. As materials for rail transit vehicles and automobile bodies, the composite materials used are not only required to have high strength, but also flame retardancy, weather resistance, and low temperature impact resistance.

[0003] CN103978693A discloses a method for preparing a continuous fiber reinforced MC nylon composite material, which is to embed a fiber mesh cloth into a fixing device, load the fiber mesh cloth into a mold at a certain interval, heat and dehydrate caprolactam, add a catalyst and an activator, and then quickly pour it into the mold, react for 5 to 10 minutes, cool it, take out the product, and obtain a continuous fiber reinforced nylon composite sheet. However, this method is intermittent reaction molding, and the strength of the resulting composite sheet is poor.

[0004] CN103847053A discloses a forming method and device for continuous long fiber reinforced MC nylon sheet, which is to heat and dehydrate caprolactam, heat and activate an activator, coat the caprolactam mixture on a continuous fiber bundle, press and dry the coated continuous fibers in sequence to obtain a continuous unidirectional long fiber reinforced MC nylon sheet; and superimpose the unidirectional continuous fiber reinforced nylon sheet at different angles to obtain a continuous long fiber reinforced MC nylon sheet. Although this method can realize the continuous preparation of unidirectional fiber reinforced nylon composite sheets, this unidirectional fiber reinforced nylon composite sheet has high axial strength and poor radial strength; superimpose the film at different angles to ensure the uniform strength of the composite material. At the same time, during the composite heating and film pressing process of the unidirectional sheet, the unidirectional fiber will produce fiber slippage as the nylon resin is heated and melted, thereby causing uneven strength of the composite sheet.

[0005] CN107840975A discloses a method for preparing a continuous fiber reinforced nylon composite material, which adopts a powder impregnation process to prepare a continuous fiber reinforced nylon composite sheet, wherein a long carbon chain nylon resin is used as a bonding material, and a glass fiber, carbon fiber, and aramid composite woven cloth are used as a skeleton material. The long carbon chain nylon resin is frozen and crushed into nylon powder, and the nylon powder is continuously sprinkled on a mixed fiber cloth, and the nylon powder is melt-impregnated into a fiber cloth after heating, and the continuous fiber reinforced composite sheet is obtained after cooling and winding, and the sheet is superimposed on the film to obtain a continuous fiber reinforced nylon composite material. However, the defect of this method is that it is difficult for the nylon powder to completely melt-impregnate the wrapped fiber in a short time, and the temperature and time of the nylon powder melt-impregnation are difficult to control, so it is difficult to obtain a plate with uniform strength, and at the same time, the production cost is very high.

[0006] CN103589138A discloses a continuous fiber reinforced polyamide composite prepreg tape and a preparation method thereof, wherein a polyamide resin is mixed with an additive, and then plasticized and melted by an extruder and extruded into a double extrusion die head, and the fibers are continuously and staggeredly introduced into the double extrusion die head, in which the polyamide resin pre-impregnates the fibers, and then the fibers are introduced into a three-roll impregnation device for further impregnation, and after cooling, a continuous fiber reinforced polyamide composite and impregnated tape is obtained. However, the defects of this method are: the viscosity of the resin melt is large, the residence time in the extruder die head is very short, the nylon resin cannot completely impregnate the coated fibers, and the manufactured composite material has the problem of uneven performance.

[0007] CN111171557A discloses a continuous fiber reinforced polyamide composite material and its preparation method and application, which uses fiber fabric as a skeleton, resin powder and resin film as bonding materials, alternately combines the resin powder and resin film with the fiber fabric into a layer or multilayer structure, and performs one-step film pressing to obtain a composite material. However, this method is a gap preparation process, with low production efficiency, and also has the defect that the resin powder is unevenly laid, resulting in uneven performance of the obtained composite material.

[0008] In summary, there are many technical defects in the existing technologies. The melt impregnation process cannot produce wide plates. The melting temperature of the resin powder used in the powder impregnation process is difficult to control, the melt impregnation speed is slow, and the impregnation and coating are difficult to be uniform. That is, both the melt impregnation and powder impregnation processes are difficult to achieve rapid and complete impregnation and coating of the fibers with the resin, resulting in uneven mechanical properties of the manufactured composite materials. At the same time, the above methods are all non-flame retardant reinforced composite materials, and are not suitable for applications in rail transit vehicles and automobile body materials.

[0009] Therefore, it is urgent to find a continuous fiber reinforced flame retardant copolymer nylon sheet with adjustable width, high strength, high toughness, flame retardancy, and the ability to replace metal sheets and its application, as well as a preparation method for continuous fiber reinforced flame retardant copolymer nylon sheet that can achieve continuous reaction molding, uniform impregnation, easy control of temperature and time, simple process, low production cost, high efficiency, and is suitable for industrial production. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a continuous fiber reinforced flame retardant copolymer nylon sheet material and its application which has adjustable width, high strength, high toughness and flame retardancy and can replace metal sheets.

[0011] The technical problem further to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing continuous fiber reinforced flame retardant copolymer nylon sheet which can realize continuous reaction molding, uniform impregnation, easy control of temperature and time, simple process, low production cost, high efficiency and is suitable for industrial production.

[0012] The technical solution adopted by the present invention to solve its technical problems is as follows: a continuous fiber reinforced flame retardant copolymer nylon sheet, mainly composed of fiber cloth and activated caprolactam in a mass ratio of 1:0.4-0.8 (more preferably 1:0.5-0.8); the activated caprolactam is mainly formed by mixing component A and component B and undergoing caprolactam anion polymerization, wherein component A includes: caprolactam, catalyst, flame retardant and coupling agent, and component B includes: caprolactam, activator, copolymer toughening monomer, antioxidant and lubricant.

[0013] The viscosity of the activated caprolactam liquid is extremely small. After heating, it forms a liquid that is almost the same as water. When this liquid is sprayed onto the surface of the fiber cloth, it can quickly penetrate into the interior of the fiber cloth and completely cover the fiber, and quickly react to form a high molecular weight resin that completely covers the fiber. The mass ratio of the fiber cloth to the activated caprolactam affects the impregnation speed and effect of the activated caprolactam on the fiber cloth to a certain extent. The higher the amount of fiber cloth, the longer the time for the activated caprolactam liquid to impregnate the fiber cloth, and it may not even be completely impregnated in a short time. Before it is completely impregnated, the activated caprolactam has already reacted quickly and solidified, and the mechanical properties of the composite material are worse. The lower the amount of fiber cloth, the easier it is for the activated caprolactam liquid to impregnate the fiber cloth. However, as the amount of fiber cloth decreases, its reinforcing effect decreases, the mechanical properties of the composite material decreases, and the cost will also be higher. Therefore, a proper ratio of fiber cloth and activated caprolactam can obtain a high-strength composite material.

[0014] The caprolactam anionic polymerization is to promote the rapid reaction of caprolactam by the interaction between the catalyst in the activated caprolactam component A and the activator in the activated caprolactam component B. The two components can react to form a solid high molecular polymer within a few minutes when they meet. Therefore, it is generally divided into two components to preserve the activated caprolactam for a long time. A catalyst is added to the A component. When the catalyst is present and heated to a certain temperature, caprolactam reacts with the catalyst to form a caprolactam salt, and then reacts rapidly to form a macromolecular polycaprolactam; the addition of a flame retardant gives the composite material flame retardancy; the coupling agent is mainly used for the surface treatment of the flame retardant. By coating the flame retardant with the coupling agent, the dispersibility of the flame retardant in the caprolactam liquid can be improved, ensuring that the flame retardant is evenly dispersed in the caprolactam liquid and does not aggregate to produce precipitation of the flame retardant. The activator in component B acts as a co-catalyst and can react quickly with sodium caprolactam to promote the macromolecular chain growth reaction; the copolymer toughening monomer reacts with caprolactam to improve the impact strength of PA6 polymer; the antioxidant functions to resist aging during processing; the use of lubricants is beneficial to improving the heating and melting speed and demolding properties of nylon resin during the subsequent processing of composite sheets.

[0015] Preferably, the fiber cloth includes one or more woven plain cloth, twill cloth or unidirectional cloth of glass fiber, carbon fiber, aramid fiber or basalt fiber. Glass fiber has high strength and low price; carbon fiber has high strength and low specific gravity, but high price; aramid fiber has extremely high strength and good compatibility with PA6, but high price; basalt fiber has a strength close to that of glass fiber. Therefore, the appropriate fiber variety can be selected according to the product application requirements.

[0016] More preferably, the fiber cloth is glass fiber cloth, glass fiber / carbon fiber cloth, glass fiber / aramid cloth, carbon fiber / aramid cloth or carbon fiber / basalt fiber cloth. In the glass fiber / carbon fiber cloth, the mass ratio of glass fiber to carbon fiber is 50-70:30-50 (more preferably 60:40); in the glass fiber / aramid cloth, the mass ratio of glass fiber to aramid is 60-80:20-40 (more preferably 70:30); in the carbon fiber / aramid cloth, the mass ratio of carbon fiber to aramid is 50-70:30-50 (more preferably 60:40); in the carbon fiber / basalt fiber cloth, the mass ratio of carbon fiber to basalt fiber is 50-70:30-50 (more preferably 60:40). The ratio of glass fiber, basalt fiber, carbon fiber and aramid in the fiber cloth can be selected according to different applications.

[0017] Preferably, the fiber cloth has a gram weight of 200 to 3000 g / m 2 (More preferably 500 to 1500 g / m 2The heavier the weight, the thicker the sheet and the longer the activated caprolactam impregnation and coating time. The weight of the fiber cloth can also be selected according to the purpose. The mass of the fiber cloth per unit time (g / min) = weight (g / m 2 )*Traction speed (m / min)*Width (m).

[0018] Preferably, the activated caprolactam is mainly prepared by mixing component A and component B at a mass ratio of 1:1.0 to 1.2 and undergoing caprolactam anionic polymerization.

[0019] Preferably, the weight proportions of the components in the activated caprolactam A component are: 50 parts of caprolactam, 0.8-1.5 parts of catalyst, 3-8 parts of flame retardant, and 0.3-1.0 parts of coupling agent.

[0020] More preferably, the weight proportions of the components in the activated caprolactam A component are: 50 parts of caprolactam, 0.8-1.2 parts of catalyst, 4-8 parts of flame retardant, and 0.3-0.5 parts of coupling agent.

[0021] Preferably, the weight proportions of the components in the activated caprolactam B component are: 50 parts of caprolactam, 1.0-2.0 parts of activator, 2-6 parts of copolymer toughening monomer, 0.5-0.8 parts of antioxidant, and 0.5-0.8 parts of lubricant.

[0022] More preferably, the weight proportions of the components in the activated caprolactam B component are: 50 parts of caprolactam, 1.0-1.5 parts of activator, 3-6 parts of copolymerized toughening monomer, 0.5-0.6 parts of antioxidant, and 0.5-0.6 parts of lubricant.

[0023] When components A and B are mixed and reacted, if the amount of catalyst is too high, the reaction speed is too fast and the curing time is short. On the one hand, it may affect the impregnation effect, and on the other hand, it may affect the growth of nylon molecular weight, resulting in a smaller molecular weight and a wider molecular weight distribution of the generated nylon resin, which makes its impact performance lower; if the amount of catalyst is too low, although it is beneficial to improve the impregnation effect, the reaction time is too long; the higher the amount of activator, the faster the reaction speed, and its effect is consistent with that of the catalyst; the higher the amount of copolymer toughening monomer, the higher the impact strength of the prepared copolymer, but the higher its cost, and it is necessary to comprehensively consider factors such as product performance requirements and cost to select the appropriate amount; the higher the amount of flame retardant, the better the flame retardancy of the composite material, but the lower the impact resistance of the composite material, and vice versa; the amount of coupling agent is related to the amount of flame retardant. The higher the amount of coupling agent, the better the coating effect on the flame retardant, and vice versa.

[0024] Preferably, the catalyst includes one or more of metallic potassium, metallic sodium, sodium hydroxide, potassium hydroxide, sodium carbonate or sodium caprolactam. The activities of the catalysts are: metallic potassium, metallic sodium, potassium hydroxide, sodium hydroxide, sodium carbonate, sodium caprolactam. The greater the catalyst activity, the faster the reaction speed. For example, metallic potassium and sodium can even completely solidify the caprolactam reaction system within 1 to 2 minutes, resulting in the activated caprolactam not having time to impregnate the fiber cloth; the catalytic effect of potassium hydroxide is second, but its price is higher; the catalytic effect of sodium hydroxide and sodium carbonate is relatively mild, and the general reaction solidification time is 5 to 20 minutes. More preferably, the catalyst is sodium hydroxide or sodium carbonate.

[0025] Preferably, the flame retardant includes one or more of red phosphorus, aluminum hypophosphite, sodium hypophosphite, iron hypophosphite or ammonium polyphosphate. Red phosphorus has the best flame retardancy and is used in the least amount, followed by aluminum hypophosphite. More preferably, the flame retardant is red phosphorus, aluminum hypophosphite or a mixture of the two in a mass ratio of 1:1 to 3.

[0026] Preferably, the coupling agent includes one or more of KH550, KH560 or KH570. Considering the fluidity and dispersibility of the coupling agent, KH550 has the lowest viscosity, which is conducive to its rapid dispersion in caprolactam and also conducive to the rapid impregnation of the activated caprolactam liquid into the fiber cloth. Therefore, the coupling agent is more preferably KH550.

[0027] Preferably, the activator includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate or triphenylmethane triisocyanate. Comprehensively considering the performance advantages of the activators, the order is: toluene diisocyanate (TDI) > diphenylmethane diisocyanate (MDI) > triphenylmethane triisocyanate (TTI) > hexamethylene diisocyanate (HDI). More preferably, the activator is toluene diisocyanate and / or diphenylmethane diisocyanate.

[0028] Preferably, the copolymer toughening monomer includes one or more of aminododecanoic acid, aminoundecanoic acid or polyetheramine, etc. In view of copolymerization reaction activity and toughening effect, the copolymer toughening monomer is more preferably aminododecanoic acid and / or aminoundecanoic acid.

[0029] Preferably, the antioxidant comprises a primary antioxidant and a secondary antioxidant. More preferably, the mass ratio of the primary antioxidant to the secondary antioxidant is 0.3-0.5:0.2-0.3.

[0030] Preferably, the primary antioxidant includes one or more of 1098, 1076, 330 or H10, etc. In view of anti-aging effect and cost, the primary antioxidant is more preferably 1098.

[0031] Preferably, the secondary antioxidant includes 168 and / or S9228, etc. In view of anti-aging effect and hydrolysis resistance, the secondary antioxidant is more preferably S9228.

[0032] Preferably, the lubricant includes one or more of silicone, EBS grafted maleic anhydride or erucic acid amide. Silicone has a better demoulding effect, while EBS grafted maleic anhydride (TAF) is more conducive to the melt fluidity of the resin. Therefore, in order to take into account both fluidity and demoulding properties, silicone or EBS grafted maleic anhydride is more preferably used, and the two can also be mixed and used, with a mass ratio of 1.5 to 2.5:1.

[0033] Preferably, the preparation method of the activated caprolactam component A is as follows: adding a catalyst, a flame retardant and a coupling agent to the caprolactam after heating, melting and dehydration, heating and stirring to react and dehydrate, and keeping warm for standby use.

[0034] Preferably, the preparation method of the activated caprolactam B component is: adding an activator, a copolymer toughening monomer, an antioxidant and a lubricant to the caprolactam after heating, melting and dehydration, heating and stirring to activate and dehydrate, and keeping warm for use.

[0035] Preferably, in the preparation method of the activated caprolactam A and B components, the temperature of heating, melting and dehydrating the caprolactam is 90 to 140°C (more preferably 110 to 130°C), the vacuum degree is -0.02 to -0.05MPa (more preferably -0.03 to -0.05MPa), and the time is 20 to 60min (more preferably 30 to 50min). If the temperature of the melting and dehydrating of caprolactam is too low, the melting and dehydrating time is too long, and the production efficiency is too low. However, if the temperature is too high, although the melting speed can be increased, the material will be rushed under vacuum conditions if the temperature is too high.

[0036] Preferably, in the preparation method of the activated caprolactam component A, the temperature of the heating and stirring reaction dehydration is 120 to 150°C (more preferably 125 to 140°C), the stirring speed is 30 to 50rpm, the vacuum degree is -0.03 to -0.06MPa (more preferably -0.03 to -0.05MPa), and the time is 10 to 40min (more preferably 20 to 30min). In the reaction of component A, caprolactam, under the action of the catalyst, catalyzes the reaction to form caprolactam sodium salt and achieves dehydration. If the reaction temperature is too low, the reaction time is long, if the reaction temperature is too high, the reaction is intense, resulting in the occurrence of material rush; if the vacuum degree is too low, the dehydration time is long, if the vacuum degree is too high, it is easy to produce material rush; if the reaction dehydration time is too short, the dehydration is incomplete, affecting the polymerization reaction, if the reaction dehydration time is too long, the caprolactam is heated for too long, and it is easy to oxidize and yellow.

[0037] Preferably, in the preparation method of the activated caprolactam component A, the insulation temperature is 130-140°C (more preferably 130-135°C) and the time is ≤4h. To avoid self-polymerization of caprolactam, it is best to prepare and use it within the insulation time.

[0038] Preferably, in the preparation method of the activated caprolactam component B, the temperature of the heating and stirring activation dehydration is 130 to 150°C (more preferably 130 to 140°C), the stirring speed is 30 to 50 rpm, the vacuum degree is -0.02 to -0.05 MPa (more preferably -0.02 to -0.03 MPa), and the time is 20 to 30 min (more preferably 25 to 30 min). In the reaction of component B, the process conditions are mainly set to ensure that the added additives are evenly dispersed in the caprolactam liquid and to remove moisture from the system.

[0039] Preferably, in the preparation method of the activated caprolactam component B, the insulation temperature is 130-150°C (more preferably 135-140°C) and the time is ≤4h. To avoid self-polymerization of caprolactam, it is best to prepare and use it within the insulation time.

[0040] The present invention further solves the technical problem by adopting the following technical solution: A method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet, comprising the following steps: (1) Unwinding the fiber cloth, preheating it, and continuously pulling it into the impregnation reaction molding mold through a pulling roller; (2) The activated caprolactam component A and component B are sent to a mixer by a continuous metering pump for mixing, and then sent to an impregnation reaction molding mold and sprayed onto the surface of the fiber cloth. The fiber cloth sprayed with activated caprolactam is sequentially impregnated, reacted, cured, and solid-phase thickening, and then calendered by a guide roller, cooled and shaped by the guide roller, air-cooled to room temperature, and rolled to obtain a continuous fiber reinforced flame-retardant copolymer nylon sheet.

[0041] Preferably, in step (1), the fiber cloth is preheated at a temperature of 120 to 160°C (more preferably 120 to 140°C) and the residence time is 10 to 30 minutes (more preferably 12 to 20 minutes). If the preheating temperature is too low, the temperature of the activated caprolactam liquid will be reduced after the fiber cloth enters the impregnation reaction molding mold, that is, the reaction temperature of components A and B will be reduced, resulting in a reduced reaction rate; if the preheating temperature is too high, the additive in the activated caprolactam sprayed onto the surface of the fiber cloth is easy to volatilize, thereby reducing the adhesion between the fiber and the caprolactam and its resin, and will also increase the reaction rate of the caprolactam, shorten the reaction curing time, and is not conducive to the complete impregnation of the fiber with the caprolactam; the preheating time is based on the equilibrium of the surface temperature of the fiber cloth.

[0042] Preferably, in step (1), the pulling speed of the unwinding and continuous pulling is 1-4 m / min (more preferably 2-4 m / min). The pulling speed not only affects the production efficiency, but also mainly affects the impregnation reaction time. When the length of the impregnation reaction molding mold is constant, the pulling speed determines the length of the reaction time, which also determines the size of the resin molecular weight, and the size of the resin molecular weight determines the mechanical properties of the composite material. Therefore, the pulling speed should be based on the complete reaction and the molecular weight of the obtained resin being sufficient to meet the performance requirements of the composite material.

[0043] Preferably, in step (2), the total pump supply of the activated caprolactam component A and component B is 0.7-3.0 kg / min. The total amount of the activated caprolactam component A and component B is matched with the traction speed, fiber cloth weight and width to ensure that the mass ratio of fiber cloth to activated caprolactam is within an appropriate range.

[0044] Preferably, in step (2), the jetting speed is 10 to 30 m / min (more preferably 10 to 20 m / min), and the jetting angle relative to the fiber cloth is 90°. When the jetting speed of the activated caprolactam is too slow, the impregnation speed of the fiber cloth is slow. The jetting speed of the activated caprolactam is as high as possible, which is more conducive to increasing the impregnation speed and improving the uniformity of the mechanical properties of the composite material.

[0045] Preferably, in step (2), the impregnation reaction molding mold is divided into: an impregnation zone, a reaction zone, a curing zone and a solid phase viscosity increasing zone in the pulling direction, where impregnation, reaction, curing and solid phase viscosity increasing occur accordingly.

[0046] Preferably, in step (2), the impregnation temperature is 140-160°C (more preferably 140-150°C), and the residence time is 0.5-2.0 min (more preferably 1.0-1.5 min). In the impregnation zone, the activated caprolactam sprayed on the fiber cloth quickly impregnates and coats the fiber cloth, and forms a low-viscosity PA6 prepolymer that adheres to the fiber cloth. If the temperature of the impregnation zone is too low, it will affect the subsequent reaction rate. If the temperature of the impregnation zone is too high, it will accelerate the reaction, which may cause the activated caprolactam to react into a polymer of a certain molecular weight before the fiber is completely impregnated, and the viscosity of the system will increase rapidly.

[0047] Preferably, in step (2), the reaction temperature is 150-170°C (more preferably 155-165°C), and the residence time is 3-10 min (more preferably 3-5 min). In the reaction zone, the activated caprolactam A and B components react rapidly to form a macromolecular chain PA6. If the temperature in the reaction zone is too low, the reaction speed is low and it is difficult to form a high molecular weight polymer. If the reaction temperature is too high, the viscosity of the reaction system will increase too quickly, and it will also be difficult to form a high molecular weight polymer.

[0048] Preferably, in step (2), the curing temperature is 150-185°C (more preferably 160-185°C), and the residence time is 3-10 min (more preferably 4-6 min). In the curing zone, a chain growth reaction occurs, which promotes further growth of the molecular weight and solidifies into a shape. The high reaction temperature in the curing zone is more conducive to the growth of the molecular weight, but when the temperature is too high, the PA6 formed will be degraded due to high temperature oxidation, which affects the formation of macromolecular PA6 and ultimately reduces the mechanical properties of the composite material.

[0049] Preferably, in step (2), the temperature of the solid phase viscosity enhancement is 180 to 220°C (more preferably 180 to 200°C), and the residence time is 10 to 30 minutes (more preferably 10 to 20 minutes). The solid phase viscosity enhancement reaction can further increase the molecular weight of PA6 and ensure that the composite material has high mechanical properties. The solid phase viscosity enhancement temperature cannot be too low. When the temperature is lower than the reaction curing temperature, the molecular weight of PA6 increases slowly. When the temperature is higher than the melting point of the PA6 resin, the resin melts and flows, which will lead to uneven thickness of the composite sheet. The solid phase viscosity enhancement time has a greater influence on the growth of the molecular weight of PA6. If the residence time of the composite sheet in the solid phase viscosity enhancement zone of the impregnation reaction molding mold is too short, the molecular weight of the resin does not increase significantly. When the residence time is too long, the PA6 resin is heated for a long time and causes its degradation. Therefore, it is necessary to reasonably control the temperature and time of the solid phase viscosity enhancement reaction.

[0050] Preferably, in step (2), the temperature of the traction calendering is 130 to 190° C. (more preferably 130 to 180° C.).

[0051] Preferably, in step (2), the guide roller for traction and calendering is a three-roll guide roller, which is first traction-calendered by guide rollers 1 and 2, and then traction-calendered by guide rollers 2 and 3, wherein the temperature of guide roller 1 is 170-190°C (more preferably 170-180°C), the temperature of guide roller 2 is 150-170°C (more preferably 150-160°C), and the temperature of guide roller 3 is 130-150°C (more preferably 130-140°C). More preferably, the temperature of solid phase viscosity enhancement> the temperature of guide roller 1> the temperature of guide roller 2> the temperature of guide roller 3. The function of the three-roll guide roller is to traction and cool and solidify. If the temperature of guide roller 1 for traction and calendering is too high, firstly, PA6 may flow easily and produce a large amount of scraps, and secondly, the thickness of the prepared sheet may be uneven and the fiber-resin ratio may be out of control; if the temperature of guide roller 3 for traction and calendering is too low, it will have an adverse effect on the surface flatness of the sheet.

[0052] Preferably, in step (2), the temperature of the cooling and shaping guide roller is 60-120°C (more preferably 80-100°C). The purpose of cooling and shaping is to ensure that the thickness of the prepared sheet is uniform. If the cooling and shaping temperature is too high, the sheet may stick and shrink when it is rolled up.

[0053] Preferably, in step (2), the product is cooled to room temperature by air via a conveyor belt.

[0054] Preferably, in step (2), the traction speed of the impregnation, reaction, curing, solid phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed of the winding are all 1 to 4 m / min (more preferably 2 to 4 m / min).

[0055] The technical solution adopted by the present invention to further solve its technical problems is as follows: an application of a continuous fiber reinforced flame retardant copolymer nylon sheet, the continuous fiber reinforced flame retardant copolymer nylon sheet is directly used in various plates, urban sewage and chemical sewage pipes, or is manufactured through superimposed film pressing to form a continuous fiber reinforced composite profile, which replaces steel plates for engineering machinery, automobiles or rail transit body materials, or manufactures various automobile parts. The continuous fiber reinforced flame retardant copolymer nylon sheet is used for large pipes, especially the skeleton material of urban sewage pipes and chemical sewage pipes, and can replace cement pipes, and has excellent corrosion resistance, aging resistance, high strength and other characteristics; the composite profile made of the continuous fiber reinforced flame retardant copolymer nylon sheet can directly replace steel, and is used in engineering machinery, automobiles, rail transit and other fields, and has excellent flame retardancy, high impact strength and other characteristics.

[0056] The beneficial effects of the present invention are as follows: (1) The continuous fiber reinforced flame retardant copolymer nylon sheet of the present invention has an adjustable width, a tensile strength of up to 350 MPa, a flexural strength of up to 480 MPa, a flexural modulus of up to 25 GPa, a heat deformation temperature of up to 210 ° C, and a notched impact strength of up to 131 kJ / m 2 The 1.6mm vertical combustion grade is V-0, which indicates that the continuous fiber reinforced flame retardant copolymer nylon sheet of the present invention has the characteristics of high strength, high toughness, flame retardancy, and can replace metal sheets; (2) The method of the present invention can realize continuous reaction molding, uniform impregnation, easy control of temperature and time, simple process, low production cost, high efficiency, suitable for industrial production, and the process and product performance are far superior to the existing melt impregnation and powder impregnation processes. DETAILED DESCRIPTION

[0057] The present invention will be further described below in conjunction with the embodiments.

[0058] The caprolactam used in the present invention was purchased from Baling Petrochemical Company; the glass fiber cloth used (weight 500g / m 2 or 1000g / m 2 , twill, width 1m) purchased from Chongqing International Composite Materials Co., Ltd., glass fiber / carbon fiber cloth (GF / CF cloth, mass ratio of 60:40, gram weight of 1000g / m 2, twill, width 1m), carbon fiber / aramid cloth (CF / KF cloth, mass ratio 60:40, gram weight 1000g / m 2 , twill, width 1m) was purchased from Jiangsu Hongfa Zongheng New Materials Co., Ltd.; the unidirectional continuous fiber reinforced PA6 composite sheet (melt impregnation composite sheet) was purchased from CGN Zhejiang Juner New Materials Co., Ltd.; red phosphorus was purchased from Sichuan Chenguang Chemical Research Institute, with a particle size of 40μm; the raw materials or chemical reagents used in the embodiments and comparative examples of the present invention, unless otherwise specified, were obtained through conventional commercial channels.

[0059] A continuous fiber reinforced flame retardant copolymer nylon sheet Example 1 to 9 The components and weight parts of Examples 1 to 9 and Comparative Example 1 of a continuous fiber reinforced flame retardant copolymer nylon sheet are shown in Table 1.

[0060] Table 1 Components and weight percentages of examples 1 to 9 and comparative example 1 of a continuous fiber reinforced flame retardant copolymer nylon sheet

[0061] Note: In the table, “-” means no addition; the mass of fiber cloth per unit time (g / min) = gram weight (g / m 2 )*traction speed (m / min)*width (m); activated caprolactam / fiber cloth = (A component pump supply + B component pump supply) (g / min) / mass of fiber cloth per unit time (g / min).

[0062] The continuous fiber reinforced flame retardant copolymer nylon sheet is composited with fiber cloth and activated caprolactam; the activated caprolactam is formed by mixing component A and component B and undergoing caprolactam anion polymerization; The preparation method of the activated caprolactam component A is as follows: according to the components and weight parts of Examples 1 to 9 in Table 1, a catalyst, a flame retardant and a coupling agent are added to the caprolactam after heating, melting and dehydration, and the mixture is heated, stirred and reacted at 125° C., a stirring speed of 40 rpm, and a vacuum degree of -0.03 MPa for 30 minutes, and then kept at 130° C. for 2 hours for standby use; The preparation method of the activated caprolactam B component is as follows: according to the components and weight parts of Examples 1 to 9 in Table 1, an activator, a copolymer toughening monomer, an antioxidant and a lubricant are added to the caprolactam after heating, melting and dehydration, and the mixture is heated, stirred and activated and dehydrated for 30 minutes at 140° C., a stirring speed of 40 rpm and a vacuum degree of -0.02 MPa, and then kept at 140° C. for 2 hours for use; The temperature of heating, melting and dehydrating the caprolactam was 110° C., the vacuum degree was -0.03 MPa, and the time was 30 min.

[0063] A method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet Example 1 (1) Place the glass fiber cloth (weight 500g / m 2 , twill, width 1m) unwinding, entering into drying oven, preheating at 140℃ for 12min, and continuously traction by traction rollers into impregnation reaction molding mold; the traction speed of unwinding and continuous traction is 2m / min; (2) According to the components and weight parts of Example 1 in Table 1, the activated caprolactam component A and component B were respectively fed to a mixer with a continuous metering pump at a pump supply of 327 g / min and 384 g / min, and then fed into an impregnation reaction molding mold, and sprayed onto the surface of the glass fiber cloth at a speed of 10 m / min and a spray angle of 90° relative to the glass fiber cloth. The glass fiber cloth sprayed with activated caprolactam was successively immersed in an impregnation zone at a temperature of 150°C and a residence time of 1.5 min, a reaction zone at a temperature of 160°C and a residence time of 3 min, and a curing zone at a temperature of 180°C and a curing time of 150°C. The residence time is 4 minutes, the temperature of the solid phase adhesion zone is 190°C, and the residence time is 15 minutes. It is first pulled and calendered by guide rollers 1 and 2 in the three-roll guide roller, and then pulled and calendered by guide rollers 2 and 3, wherein the temperature of guide roller 1 is 180°C, the temperature of guide roller 2 is 160°C, and the temperature of guide roller 3 is 140°C. When the guide roller temperature is 100°C, it is cooled and shaped, and air-cooled to room temperature through a conveyor belt, and wound up to obtain a continuous fiber reinforced flame-retardant copolymer nylon sheet; the pulling speed of the impregnation, reaction, curing, solid phase adhesion, pulling calendering, cooling and shaping and the winding speed of winding up are all 2m / min.

[0064] A method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet Example 2 (1) Place glass fiber cloth (weight 1000g / m 2 , twill, width 1m) unwinding, entering into drying oven, preheating at 120℃ for 12min, and continuously traction by traction rollers into impregnation reaction molding mold; the traction speed of unwinding and continuous traction is 2m / min; (2) According to the components and weight parts of Example 2 in Table 1, the activated caprolactam component A and component B were respectively delivered to a mixer by a continuous metering pump at a pump supply of 651 g / min and 682 g / min, and then delivered to an impregnation reaction molding mold, and sprayed onto the surface of the glass fiber cloth at a speed of 10 m / min and a spray angle of 90° relative to the glass fiber cloth. The glass fiber cloth sprayed with activated caprolactam was successively immersed in an impregnation zone at a temperature of 150°C and a residence time of 1.5 min, a reaction zone at a temperature of 165°C and a residence time of 3 min, and a curing zone at a temperature of 185°C and a curing time of 150°C and 165°C, respectively. The residence time is 4 minutes, the temperature of the solid phase adhesion zone is 190°C, and the residence time is 15 minutes. It is first pulled and calendered by guide rollers 1 and 2 in the three-roll guide roller, and then pulled and calendered by guide rollers 2 and 3, wherein the temperature of guide roller 1 is 180°C, the temperature of guide roller 2 is 160°C, and the temperature of guide roller 3 is 140°C. When the guide roller temperature is 80°C, it is cooled and shaped, and air-cooled to room temperature through a conveyor belt, and wound up to obtain a continuous fiber reinforced flame-retardant copolymer nylon sheet; the pulling speed of the impregnation, reaction, curing, solid phase adhesion, pulling and calendering, cooling and shaping and the winding speed of winding up are all 2m / min.

[0065] Example 3 of a method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet (1) Place glass fiber cloth (weight 1000g / m 2 , twill, width 1m) unwinding, entering into drying oven, preheating at 120℃ for 14min, and continuously traction by traction rollers into impregnation reaction molding mold; the traction speed of unwinding and continuous traction is 3m / min; (2) The difference between this step and step (2) of method example 2 is that: according to the components and weight parts of Example 3 in Table 1, the activated caprolactam component A and component B are mixed by a continuous metering pump at a pump supply of 975 g / min and 1025 g / min respectively; the injection speed is 15 m / min; the traction speed for impregnation, reaction, curing, solid phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed for winding are all 3 m / min; the rest is the same as step (2) of method example 2.

[0066] Example 4 of a method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet (1) This step is different from step (1) of method embodiment 2 only in that the traction speeds of unwinding and continuous traction are both 3 m / min; the rest is the same as step (1) of method embodiment 2; (2) The difference between this step and step (2) of method example 2 is that: according to the components and weight parts of Example 4 in Table 1, the activated caprolactam component A and component B are mixed by a continuous metering pump at a pump supply of 966 g / min and 1034 g / min respectively; the traction speed for impregnation, reaction, curing, solid phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed for winding are all 3 m / min; the rest is the same as step (2) of method example 2.

[0067] A method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet Example 5 (1) This step is different from step (1) of method embodiment 1 only in that the traction speeds of unwinding and continuous traction are both 4 m / min; the rest is the same as step (1) of method embodiment 2; (2) The difference between this step and step (2) of method example 2 is that: according to the components and weight parts of Example 5 in Table 1, the activated caprolactam component A and component B are mixed by continuous metering pumps at pump supply rates of 1293 g / min and 1374 g / min, respectively; the residence time of solid phase viscosity enhancement in the solid phase viscosity enhancement zone is 10 min; the traction speed for impregnation, reaction, curing, solid phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed for winding are all 4 m / min; the rest is the same as step (2) of method example 2.

[0068] Example 6 Preparation method of continuous fiber reinforced flame retardant copolymer nylon sheet (1) This step is different from step (1) of method embodiment 2 only in that the traction speeds of unwinding and continuous traction are both 3 m / min; the rest is the same as step (1) of method embodiment 2; (2) The difference between this step and step (2) of Example 2 is that: according to the components and weight parts of Example 6 in Table 1, the activated caprolactam component A and component B are mixed at pump supply rates of 966 g / min and 1034 g / min respectively; the residence time of solid phase viscosity enhancement in the solid phase viscosity enhancement zone is 20 min; the traction speed for impregnation, reaction, curing, solid phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed for winding are all 3 m / min; the rest is the same as step (2) of method example 2.

[0069] A method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet Example 7 (1) This step is the same as step (1) in method embodiment 2; (2) This step differs from step (2) of method example 2 only in that: according to the components and weight parts of Example 7 in Table 1, the activated caprolactam component A and component B are mixed at pump supply rates of 702 g / min and 743 g / min, respectively; the rest is the same as step (2) of method example 2.

[0070] Example 8 Preparation Method of Continuous Fiber Reinforced Flame Retardant Copolymer Nylon Sheet (1) The difference between this step and step (1) of method embodiment 2 is that: GF / CF cloth (weight 1000g / m 2 , twill, width 1m); the rest is the same as step (1) of method embodiment 2; (2) This step differs from step (2) of method example 2 only in that: according to the components and weight parts of Example 8 in Table 1, the activated caprolactam component A and component B are mixed at pump supply rates of 707 g / min and 738 g / min, respectively; the rest is the same as step (2) of method example 2.

[0071] Example 9 of a method for preparing a continuous fiber reinforced flame retardant copolymer nylon sheet (1) The difference between this step and step (1) of method embodiment 2 is that: CF / KF cloth (weight 1000g / m 2 , twill, width 1m); the rest is the same as step (1) of method embodiment 2; (2) This step differs from step (2) of method example 2 only in that: according to the components and weight parts of Example 9 in Table 1, the activated caprolactam component A and component B are mixed at pump supply rates of 707 g / min and 738 g / min, respectively; the rest is the same as step (2) of method example 2.

[0072] Application Examples 1 to 9 of a Continuous Fiber Reinforced Flame Retardant Copolymer Nylon Sheet The continuous fiber reinforced flame retardant copolymer nylon sheet examples 1 to 9 are respectively laminated and molded into continuous fiber reinforced composite profiles, which are used in engineering machinery, automobile or rail transit body materials instead of steel plates.

[0073] Comparative Example 1 (1) This step is the same as step (1) in method embodiment 3; (2) The difference between this step and step (2) of method example 3 is that: according to the components and weight parts of comparative example 1 in Table 1, the activated caprolactam component A and component B are mixed to finally obtain a continuous fiber reinforced copolymer nylon sheet; the rest is the same as step (2) of method example 3.

[0074] Comparative Example 2 (1) Place the glass fiber cloth (weight 200g / m 2 , twill, width 1m) unwinding, entering the drying oven, preheating at 120°C for 2 minutes, and continuously traction by traction rollers to send into the impregnation coating die head; the traction speed of the unwinding and continuous traction is 2m / min; (2) The PA6 mixed melt (PA6 (intrinsic viscosity 2.1) 100 kg, red phosphorus 5 kg, primary antioxidant 1098 0.3 kg, secondary antioxidant S9228 0.2 kg, silicone 0.5 kg) was melt-extruded through a twin-screw extruder. The extrusion temperatures in different temperature zones from the feed head to the extrusion die were 240°C, 250°C, 250°C, 260°C, 260°C, 260°C, 270°C, the screw speed was 400prm, the vacuum degree was -0.06MPa, the extrusion amount was 267g / min (glass fiber cloth: PA6 mixed melt = 1:0.67), and then fed from the top of the impregnation coating die head and at the entrance of the glass fiber cloth. The impregnation die outlet temperature is 240°C, and the cooling guide roller pulls out of the impregnation and coating die. The temperature of the three-roll cooling guide roller group is 180°C, 160°C, and 140°C respectively, and the sheet is calendered and cooled to shape. After air cooling to room temperature, the sheet is wound at a speed of 2m / min to obtain a PA6 melt-impregnated glass fiber composite sheet.

[0075] Comparative Example 3 (1) Preparation of mixed powder: 40 kg PA6 powder (particle size 100 mesh) was mixed with 0.3 kg antioxidant 1098, 0.2 kg antioxidant 168, 0.5 kg coupling agent KH550, and 0.5 kg lubricant silicone to obtain a PA6 mixture, which was added to the powder hopper; (2) Preparation of composite sheet: 60 kg glass fiber cloth (weight 1000 g / m 2 The glass fiber cloth is unwound (twill, width 1m), and is sent to the preheater through the traction roller, preheated at 120℃, and enters the powder feeding device through the traction roller at a traction speed of 1m / min. The PA6 mixture is continuously and evenly sprinkled on the surface of the glass fiber cloth at a feed rate of 400g / min, and then enters the heater for heating. The PA6 mixture is melted and impregnated with the glass fiber cloth under heating at 260℃. After cooling, shaping and winding, the PA6 powder impregnated glass fiber composite sheet is obtained.

[0076] In order to evaluate the performance of the continuous fiber reinforced flame retardant copolymer nylon sheets obtained in Examples 1 to 9 of the present invention, the continuous fiber reinforced copolymer nylon sheet obtained in Comparative Example 1, the PA6 melt-impregnated glass fiber composite sheet obtained in Comparative Example 2, and the PA6 powder-impregnated glass fiber composite sheet obtained in Comparative Example 3, samples were prepared to test the performance of the composite materials.

[0077] Specific sample preparation method: stack the above sheets respectively, and mold them at 230℃ and 1.5MPa for 3min to make a plate with standard thickness of 3mm. Keep the pressure at 1.0MPa and temperature of 230℃ for 30min, cool down to 60℃ for 30min, and take out. Prepare specimens according to the test standards.

[0078] Performance testing standards: tensile strength MPa: ASTM D638, flexural strength MPa: ASTM D790, flexural modulus GPa: ASTM D790, heat deformation temperature ℃: ASTM D648 (1.86MPa); notched impact strength kJ / m 2 : ASTM D256; Flame test: UL-94.

[0079] Table 2 Performance test results of the composite sheets obtained from Examples 1 to 9 and Comparative Examples 1 to 3 of a continuous fiber reinforced flame retardant copolymer nylon sheet

[0080] As shown in Table 2, compared with Example 3 of the present invention, Comparative Example 1 does not add flame retardant, and other components and processes are consistent with Example 1 of the present invention. It can be seen that the tensile strength, flexural strength, flexural modulus, and heat deformation temperature of Comparative Example 1 are basically consistent with those of Example 3 of the present invention, but its notched impact strength is 1.08 times that of Example 3, which is in line with the actual law. Generally, the addition of flame retardant has a certain decrease in the mechanical properties of the composite material, and Comparative Example 1 is not flame retardant and can only be used in non-combustion-resistant occasions.

[0081] As can be seen from Table 2, the average tensile strength of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is 318.6 MPa, up to 350 MPa, and the average tensile strength is 1.2 times and 1.23 times that of the composite sheets obtained in Comparative Examples 2 and 3, respectively; the average flexural strength of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is 459.6 MPa, up to 480 MPa, and the average flexural strength is 1.08 times and 1.18 times that of the composite sheets obtained in Comparative Examples 2 and 3, respectively; the average flexural modulus of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is 20 GPa, up to 25 GPa, and the average flexural modulus is 1.25 times and 1.43 times that of the composite sheets obtained in Comparative Examples 2 and 3, respectively; the average notched impact strength of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is 123.9 kJ / m 2 , up to 131kJ / m 2, the average notched impact strength is 1.24 times and 1.26 times that of the composite sheets obtained in Comparative Examples 2 and 3 respectively; the average heat deformation temperature of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is 208.3°C, and the highest is 210°C. Although the heat deformation temperature of embodiment 9 is not as high as that of embodiments 1 to 8, this is because the heat deformation temperature of aramid is lower than the heat resistance of glass fiber and carbon fiber, but its tensile strength is greater than that of the glass fiber cloth of embodiments 1 to 7 and the glass fiber / carbon fiber cloth used in embodiment 8. The heat deformation temperatures of comparative examples 2 and 3 are both lower than those of embodiments 1 to 8, which is due to the uneven coating of the fibers by PA6; in summary, it is shown that the performance of the continuous fiber reinforced flame retardant copolymer nylon sheet embodiments 1 to 9 of the present invention is significantly better than that of the existing composite sheets obtained by melt impregnation and powder impregnation.

Claims

1. A continuous fiber reinforced flame retardant copolymer nylon sheet, characterized in that: It is mainly composed of fiber cloth and activated caprolactam in a mass ratio of 1:0.4-0.8; the activated caprolactam is mainly formed by mixing component A and component B and undergoing caprolactam anion polymerization, wherein component A includes: caprolactam, catalyst, flame retardant and coupling agent, and component B includes: caprolactam, activator, copolymer toughening monomer, antioxidant and lubricant.

2. The continuous fiber reinforced flame retardant copolymer nylon sheet according to claim 1, characterized in that: The fiber cloth includes one or more woven plain cloth, twill cloth or unidirectional cloth selected from glass fiber, carbon fiber, aramid fiber or basalt fiber; the weight of the fiber cloth is 200-3000 g / m 2 .

3. The continuous fiber reinforced flame retardant copolymer nylon sheet according to claim 1 or 2, characterized in that: The activated caprolactam is mainly prepared by mixing component A and component B at a mass ratio of 1:1.0-1.2 and undergoing caprolactam anion polymerization; the weight parts of the components in the activated caprolactam component A are: 50 parts of caprolactam, 0.8-1.5 parts of catalyst, 3-8 parts of flame retardant, and 0.3-1.0 parts of coupling agent; the weight parts of the components in the activated caprolactam component B are: 50 parts of caprolactam, 1.0-2.0 parts of activator, 2-6 parts of copolymer toughening monomer, 0.5-0.8 parts of antioxidant, and 0.5-0.8 parts of lubricant; the catalyst includes one or more of metallic potassium, metallic sodium, sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium caprolactam; the flame retardant includes red phosphorus, aluminum hypophosphite, One or more of sodium hypophosphite, ferric hypophosphite or ammonium polyphosphate; the coupling agent includes one or more of KH550, KH560 or KH570; the activator includes one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate or triphenylmethane triisocyanate; the copolymer toughening monomer includes one or more of aminododecanoic acid, aminoundecanoic acid or polyetheramine; the antioxidant includes a primary antioxidant and a secondary antioxidant; the primary antioxidant includes one or more of 1098, 1076, 330 or H10; the secondary antioxidant includes 168 and / or S9228; the lubricant includes one or more of silicone, EBS grafted maleic anhydride or erucamide.

4. The continuous fiber reinforced flame retardant copolymer nylon sheet according to any one of claims 1 to 3, characterized in that: The preparation method of the activated caprolactam component A is as follows: adding a catalyst, a flame retardant and a coupling agent to the caprolactam after heating, melting and dehydration, heating and stirring for reaction and dehydration, and keeping warm for use; the preparation method of the activated caprolactam component B is as follows: adding an activator, a copolymer toughening monomer, an antioxidant and a lubricant to the caprolactam after heating, melting and dehydration, heating and stirring for activation and dehydration, and keeping warm for use.

5. The continuous fiber reinforced flame retardant copolymer nylon sheet according to claim 4, characterized in that: In the preparation method of the activated caprolactam A and B components, the temperature of heating, melting and dehydrating the caprolactam is 90-140°C, the vacuum degree is -0.02-0.05MPa, and the time is 20-60min; in the preparation method of the activated caprolactam A component, the temperature of heating, stirring, reacting and dehydrating is 120-150°C, the stirring speed is 30-50rpm, the vacuum degree is -0.03-0.06MPa, and the time is 10-40min; in the preparation method of the activated caprolactam A component, the insulation temperature is 130-140°C, and the time is ≤4h; in the preparation method of the activated caprolactam B component, the temperature of heating, stirring, activating and dehydrating is 130-150°C, the stirring speed is 30-50rpm, the vacuum degree is -0.02-0.05MPa, and the time is 20-30min; in the preparation method of the activated caprolactam B component, the insulation temperature is 130-150°C, and the time is ≤4h.

6. A method for preparing the continuous fiber reinforced flame retardant copolymer nylon sheet as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Unwinding the fiber cloth, preheating it, and continuously pulling it into the impregnation reaction molding mold through a pulling roller; (2) The activated caprolactam component A and component B are sent to a mixer by a continuous metering pump for mixing, and then sent to an impregnation reaction molding mold and sprayed onto the surface of the fiber cloth. The fiber cloth sprayed with activated caprolactam is sequentially impregnated, reacted, cured, and solid-phase thickening, and then calendered by a guide roller, cooled and shaped by the guide roller, air-cooled to room temperature, and rolled to obtain a continuous fiber reinforced flame-retardant copolymer nylon sheet.

7. The method for preparing the continuous fiber reinforced flame retardant copolymer nylon sheet according to claim 6, characterized in that: In step (1), the preheating temperature of the fiber cloth is 120-160° C., and the residence time is 10-30 min; the unwinding and continuous traction speeds are both 1-4 m / min.

8. The method for preparing the continuous fiber reinforced flame retardant copolymer nylon sheet according to claim 6 or 7, characterized in that: In step (2), the total pump supply of the activated caprolactam component A and component B is 0.7-3.0 kg / min; the injection speed is 10-30 m / min, and the injection angle relative to the fiber cloth is 90°; the impregnation temperature is 140-160°C, and the residence time is 0.5-2.0 min; the reaction temperature is 150-170°C, and the residence time is 3-10 min; the curing temperature is 150-185°C, and the residence time is 3-10 min; the solid phase viscosity enhancement temperature is 180-220°C, and the residence time is 10 ~30min; the temperature of the traction and calendering is 130~190℃; the guide roller for traction and calendering is a three-roller guide roller, which is first traction-calendered by guide rollers 1 and 2, and then traction-calendered by guide rollers 2 and 3, wherein the temperature of guide roller 1 is 170~190℃, the temperature of guide roller 2 is 150~170℃, and the temperature of guide roller 3 is 130~150℃; the temperature of the guide roller for cooling and shaping is 60~120℃; it is air-cooled to room temperature via a conveyor belt; the traction speed of the impregnation, reaction, solidification, solid-phase viscosity enhancement, traction calendering, cooling and shaping and the winding speed of winding are all 1~4m / min.

9. An application of the continuous fiber reinforced flame retardant copolymer nylon sheet as claimed in any one of claims 1 to 5, characterized in that: The continuous fiber reinforced flame retardant copolymer nylon sheet according to any one of claims 1 to 5 is directly used for various plates, urban sewage and chemical sewage pipes, or is manufactured through stacked film compression molding to manufacture continuous fiber reinforced composite profiles, which can replace steel plates for construction machinery, automobile or rail transit body materials, or manufacture various automobile parts.

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