Flame-retardant glass fiber, preparation method thereof and fiber-reinforced thermoplastic composite material

Abstract

The invention belongs to the technical field of materials, and particularly relates to a flame-retardant glass fiber, a preparation method thereof and a fiber-reinforced thermoplastic composite material. Compared with the prior art, the flame-retardant glass fiber provided by the invention has the advantages that the flame-retardant coating loaded by utilizing the characteristic of large specific surface area of the glass fiber has an efficient flame retardant with a rapid catalytic carbon formation function and has a synergistic flame-retardant function; when being used for preparing a fiber reinforced thermoplastic composite material, the flame retardant can promote carbon formation of a flame retardant added outside a matrix on an interface layer of flame-retardant glass fiber and a resin matrix, so that the synergistic flame-retardant effect is achieved, the carbon formation quality and efficiency are improved to inhibit the wick effect of fiber, the flame-retardant property is improved, the dosage of the flame retardant added outside in the granulation process can be reduced, and the production cost is reduced. The mechanical property can be improved while the production cost is reduced, and the method has a wide application prospect in actual industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of materials, and particularly relates to a flame-retardant glass fiber, a preparation method thereof and a fiber-reinforced thermoplastic composite material. BACKGROUND

[0002] Glass fiber is an inorganic non-metallic material with excellent performance. The thermoplastic composite material reinforced by glass fiber improves the deficiencies of the thermoplastic resin in strength, hardness and heat resistance, and has excellent comprehensive performance, and is widely used in building materials, electronic appliances, aerospace, automobiles and rail transportation.

[0003] With the continuous improvement of people's safety awareness in the use of materials, there are strict requirements on the flame-retardant performance of materials. However, several commonly used thermoplastic resins are flammable or combustible materials. In order to meet the corresponding regulatory requirements and achieve the corresponding flame-retardant grade, a certain amount of flame retardant is usually added during the granulation process. However, the addition of glass fiber worsens the flame-retardant performance of the composite material due to the "wick effect" caused by its shape characteristics and physical properties. In order to meet the flame-retardant requirements, more flame retardants need to be added to the composite material during the production of the glass fiber-reinforced thermoplastic composite material, resulting in an increase in production cost and a decrease in performance.

[0004] The flame-retardant glass fiber disclosed in the publication No. CN117700836A flame-retardant glass fiber and its preparation method, thermoplastic resin composite material discloses a preparation method of flame-retardant glass fiber. The flame-retardant glass fiber comprises glass fiber and a coating layer coated on the surface of the glass fiber. The coating layer comprises a phosphorus-containing silane coupling agent. However, its flame-retardant performance still needs to be improved. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to provide a flame-retardant glass fiber with high flame-retardant performance, a preparation method thereof and a fiber-reinforced thermoplastic composite material.

[0006] The present application provides a flame-retardant glass fiber, comprising: glass fiber and a flame-retardant coating layer attached to the surface of the glass fiber; the flame-retardant coating layer comprises a flame retardant, an amino silane coupling agent and a film forming agent.

[0007] The flame retardant is selected from a complex formed by a phosphite compound and iron ions and / or a complex formed by a phosphite-grafted resin and iron ions.

[0008] The mass of the flame retardant is 0.5% to 20% of the mass of the flame-retardant coating layer.

[0009] The mass of the amino silane coupling agent is 0.5% to 20% of the mass of the flame-retardant coating layer.

[0010] The mass of the film forming agent is 60% to 99% of the mass of the flame-retardant coating layer.

[0011] Preferably, the content of iron ions in the flame retardant is 1-3wt%;

[0012] The phosphinic acid compound is selected from one or more of aminotrimethylene phosphonic acid, ethylenediamine tetramethylene phosphonic acid, diethylene triamine pentamethylene phosphonic acid and hydroxy ethylene diphosphonic acid;

[0013] The grafting phosphorous acid resin is selected from grafting polyethylene imine phosphorous acid.

[0014] Preferably, the molecular weight of the polyethylene imine in the grafting polyethylene imine phosphorous acid is 300-600g / mol;

[0015] And / or, the amino silane coupling agent is selected from γ-aminopropyl triethoxysilane and / or γ-aminoethyl aminopropyl trimethoxysilane;

[0016] And / or, the film forming agent is selected from polyurethane film forming agent and / or epoxy film forming agent;

[0017] And / or, the flame retardant coating further comprises an auxiliary agent; the mass of the auxiliary agent is 0.1%-8% of the mass of the flame retardant coating.

[0018] Preferably, the complex of the phosphinic acid compound and iron ions is prepared by mixing an aqueous solution of the phosphinic acid compound with an iron salt solution, then adjusting the pH value of the system to neutral, to obtain a solution containing the complex of the phosphinic acid compound and iron ions;

[0019] The complex of the grafting phosphorous acid resin and iron ions is prepared by mixing a resin solution with a phosphorous acid solution, then adding a formaldehyde solution, then adding an iron salt solution, and finally adjusting the pH value of the system to neutral, to obtain a solution containing the complex of the grafting phosphorous acid resin and iron ions.

[0020] Preferably, the film forming agent is selected from polyurethane film forming agent and epoxy film forming agent; the mass ratio of the polyurethane film forming agent to the epoxy film forming agent is (1-5):5;

[0021] And / or, the polyurethane film forming agent is selected from polyester type polyurethane film forming agent; the epoxy film forming agent is selected from modified epoxy film forming agent;

[0022] And / or, the epoxy equivalent weight of the epoxy film forming agent is 200-500;

[0023] And / or, the auxiliary agent is selected from wetting agent and / or lubricant.

[0024] Preferably, the mass of the flame retardant coating is 1%-3% of the mass of the flame retardant glass fiber.

[0025] The application also provides a preparation method of the above-mentioned flame-retardant glass fiber, comprising the following steps:

[0026] S1) mixing the hydrolyzed amino silane coupling agent, the film-forming agent solution and the flame retardant in water to obtain an infiltration water agent;

[0027] S2) coating the infiltration water agent on the surface of the glass fiber and drying to obtain the flame-retardant glass fiber. Preferably, the film-forming agent solution is selected from a polyurethane film-forming agent solution and / or an epoxy film-forming agent solution;

[0028] The solid content of the polyurethane film-forming agent solution is preferably 48% to 50%;

[0029] The viscosity of the polyurethane film-forming agent solution is 100 to 1000 mpa.s;

[0030] The particle size of the polyurethane film-forming agent solution is 200 to 500 nm;

[0031] The solid content of the epoxy film-forming agent solution is 58% to 62%;

[0032] The viscosity of the epoxy film-forming agent solution is 100 to 3000 mpa.s;

[0033] The particle size of the epoxy film-forming agent solution is 200 to 1400 nm.

[0034] Preferably, the solid content of the infiltration water agent is 5% to 20%;

[0035] The moisture content of the flame-retardant glass fiber is less than 0.05%;

[0036] The coating method in the step S2) is roller coating, and the line speed of the roller coating is 10 to 20 m / min.

[0037] The application also provides a fiber-reinforced thermoplastic composite material comprising the above-mentioned flame-retardant glass fiber and a thermoplastic resin.

[0038] Compared with the prior art, the flame-retardant glass fiber provided by the application has a high-efficiency flame retardant with a rapid catalytic carbonization function loaded by taking advantage of the large specific surface area of the glass fiber, and has a synergistic flame-retardant function. When used for preparing a fiber-reinforced thermoplastic composite material, the flame-retardant glass fiber can promote the carbonization of the externally added flame retardant in the interface layer between the flame-retardant glass fiber and the resin matrix, achieve a synergistic flame-retardant effect, improve the carbonization quality and efficiency to inhibit the wick effect of the fiber, improve the flame-retardant performance, reduce the amount of externally added flame retardant in the granulation process, reduce the production cost while improving the mechanical properties, and has a broad application prospect in actual industrial production.

[0039] The test results show that the composite material prepared by the flame-retardant glass fiber has the flame-retardant performance reaching UL94 V0 level, the comprehensive mechanical performance is improved by 5-10% and the production cost of the flame-retardant granules is reduced by about 10% under the condition of reducing the amount of the flame retardant by 20%. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] The present application provides a kind of flame-retardant glass fiber, comprising: glass fiber and the flame-retardant coating attached to the surface of glass fiber;The flame-retardant coating includes flame retardant, amino silane coupling agent and film forming agent;The flame retardant is the complex of phosphite compound and iron ion and / or the complex of resin grafted phosphite and iron ion;The mass of the flame retardant is 0.5%~20% of the mass of flame-retardant coating;The mass of the amino silane coupling agent is 0.5%~20% of the mass of flame-retardant coating;The mass of the film forming agent is 60%~99% of the mass of flame-retardant coating.

[0042] In a specific embodiment provided by the present application, the diameter of the glass fiber is preferably 8-20 microns;Optionally, the diameter of the glass fiber is 8 microns, 10 microns, 12 microns, 14 microns, 17 microns, 20 microns or a range between any two of the above values.

[0043] The present application uses the complex containing phosphite group and iron ion as flame retardant, and the content of iron ion in the flame retardant is preferably 1-3wt%;Optionally, the content of iron ion in the flame retardant is 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt% or a range between any two of the above values.

[0044] In a specific embodiment provided by the present application, the flame retardant is the complex of phosphite compound and iron ion;The content of iron ion in the flame retardant is preferably 1-3wt%, more preferably 2wt%.

[0045] In a specific embodiment provided by the present application, the complex of phosphite compound and iron ion is prepared by mixing the aqueous solution of phosphite compound and the solution of iron salt, and then adjusting the pH value of the system to neutral to obtain the solution containing the complex of phosphite compound and iron ion.

[0046] In one specific embodiment provided by the present application, the phosphonous acid compound is preferably one or more of aminotri(methylene)phosphonic acid, ethylenediaminetetra(methylene)phosphonic acid, diethylenetriaminepenta(methylene)phosphonic acid, and hydroxyethylidene-1,1-diphosphonic acid.

[0047] In one specific embodiment provided by the present application, the iron salt is preferably a soluble iron salt known to those skilled in the art, and there is no particular limitation. In the present application, ferric nitrate is preferred.

[0048] In one specific embodiment provided by the present application, the mass concentration of the phosphonous acid compound in the aqueous solution of the phosphonous acid compound is preferably 10% to 30%; alternatively, the mass concentration of the phosphonous acid compound in the aqueous solution of the phosphonous acid compound is 10%, 15%, 20%, 25%, 30%, or a range between any two of the above values; the mass concentration of the iron salt in the iron salt solution is preferably 10% to 30%; alternatively, the mass concentration of the iron salt in the iron salt solution is 10%, 15%, 20%, 25%, 30%, or a range between any two of the above values; and the volume ratio of the aqueous solution of the phosphonous acid compound to the iron salt solution is preferably 100:(0.5 to 3); alternatively, the volume ratio of the aqueous solution of the phosphonous acid compound to the iron salt solution is 100:0.5, 100:1, 100:2, 100:3, or a range between any two of the above values.

[0049] In one specific embodiment provided by the present application, the mass concentration of the phosphonous acid compound in the aqueous solution of the phosphonous acid compound is preferably 20%; the mass concentration of the iron salt in the iron salt solution is preferably 20%; and the volume ratio of the aqueous solution of the phosphonous acid compound to the iron salt solution is preferably 100:1.

[0050] In one specific embodiment provided by the present application, the iron salt solution is preferably slowly added to the aqueous solution of the phosphonous acid compound for mixing.

[0051] In one specific embodiment provided by the present application, the temperature for mixing the aqueous solution of the phosphonous acid compound and the iron salt solution is preferably 70°C to 90°C; alternatively, the temperature for mixing the aqueous solution of the phosphonous acid compound and the iron salt solution is 70°C, 75°C, 80°C, 85°C, 90°C, or a range between any two of the above values; and the mixing time is preferably 1 to 3 hours; alternatively, the mixing time is 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or a range between any two of the above values.

[0052] In one specific embodiment provided by the present application, the temperature for mixing the aqueous solution of the phosphonous acid compound and the iron salt solution is preferably 80°C; and the mixing time is preferably 2 hours.

[0053] In one embodiment of the present application, the pH of the system is adjusted to neutral by using ammonia.

[0054] In one embodiment of the present application, the solid content of the solution containing the complex of phosphinic compound and iron ion is preferably 20% to 50%; alternatively, the solid content of the solution containing the complex of phosphinic compound and iron ion is 20%, 25%, 30%, 35%, 40%, 45%, 50% or a range between any two of the above values.

[0055] In one embodiment of the present application, the solid content of the solution containing the complex of phosphinic compound and iron ion is preferably 35%.

[0056] In one embodiment of the present application, the content of iron ion in the flame retardant is preferably 2 to 3 wt%, more preferably 2.5 wt%.

[0057] In one embodiment of the present application, the grafted phosphinic acid resin is selected from grafted polyethyleneimine phosphinic acid; the molecular weight of the polyethyleneimine in the grafted polyethyleneimine phosphinic acid is preferably 300 to 600 g / mol.

[0058] In one embodiment of the present application, the complex of grafted phosphinic acid resin and iron ion is prepared by mixing the resin solution and the phosphinic acid solution, then adding the formaldehyde solution, followed by adding the iron salt solution, and finally adjusting the pH of the system to neutral to obtain the solution containing the complex of grafted phosphinic acid resin and iron ion.

[0059] In a specific embodiment provided by the present application, the mass concentration of the resin in the resin solution is preferably 5% to 20%; alternatively, the mass concentration of the resin in the resin solution is 5%, 10%, 15%, 20%, or a range between any two of the above values; the mass concentration of the phosphorous acid solution is preferably 10% to 40%; alternatively, the mass concentration of the phosphorous acid solution is 10%, 15%, 20%, 25%, 30%, 35%, 40%, or a range between any two of the above values; the volume ratio of the resin solution to the phosphorous acid solution is preferably (2 to 5) : 1; alternatively, the volume ratio of the resin solution to the phosphorous acid solution is 2:1, 3:1, 4:1, 5:1, or a range between any two of the above values; the mass concentration of formaldehyde in the formaldehyde solution is preferably 35% to 40%; alternatively, the mass concentration of the formaldehyde solution is 35%, 36%, 37%, 38%, 39%, 40%, or a range between any two of the above values; the volume ratio of the resin solution to the formaldehyde solution is preferably (15 to 20) : 1; alternatively, the volume ratio of the resin solution to the formaldehyde solution is 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, or a range between any two of the above values; the mass concentration of the iron salt in the iron salt solution is preferably 10% to 30%; alternatively, the mass concentration of the iron salt in the iron salt solution is 10%, 15%, 20%, 25%, 30%, or a range between any two of the above values; the volume ratio of the resin solution to the iron salt solution is preferably (30 to 50) : 1; alternatively, the volume ratio of the resin solution to the iron salt solution is 30:1, 35:1, 40:1, 45:1, 50:1, or a range between any two of the above values.

[0060] In a specific embodiment provided by the present application, the mass concentration of the resin in the resin solution is preferably 7% to 10%; the mass concentration of the phosphorous acid solution is preferably 20%; the volume ratio of the resin solution to the phosphorous acid solution is preferably 3:1; the mass concentration of formaldehyde in the formaldehyde solution is preferably 37%; the volume ratio of the resin solution to the formaldehyde solution is preferably 17:1; the mass concentration of the iron salt in the iron salt solution is preferably 20%; and the volume ratio of the resin solution to the iron salt solution is preferably 40:1.

[0061] In one specific embodiment provided by the present application, the resin solution and the phosphorous acid solution are preferably mixed at room temperature; the mixing time of the resin solution and the phosphorous acid solution is preferably 30-90 min, more preferably 50-80 min, and even more preferably 60 min; the rotation speed of the mixing of the resin solution and the phosphorous acid solution is preferably 500-1000 rpm, more preferably 600-900 rpm, and even more preferably 800 rpm; the temperature of the mixing with the formaldehyde solution is preferably 100-120°C, more preferably 110°C; the mixing time with the formaldehyde solution is preferably 2-6 h, more preferably 3-5 h, and even more preferably 4 h; the rotation speed of the mixing with the formaldehyde solution is preferably 1000-1500 rpm, more preferably 1100-1400 rpm, and even more preferably 1200 rpm; the temperature of the mixing with the iron salt solution is preferably 70-90°C, more preferably 75-85°C, and even more preferably 80°C; the mixing time with the iron salt solution is preferably 1-3 h, more preferably 1.5-2.5 h, and even more preferably 2 h; and the rotation speed of the mixing with the iron salt solution is preferably 1000-1500 rpm, more preferably 1100-1400 rpm, and even more preferably 1200 rpm.

[0062] In one specific embodiment provided by the present application, the pH value of the system is adjusted to neutral by using ammonia.

[0063] In one specific embodiment provided by the present application, the solid content of the solution of the complex of the phosphorous acid-containing resin and the iron ion is preferably 20-50%; alternatively, the solid content of the solution of the complex of the phosphorous acid-containing resin and the iron ion is 20%, 25%, 30%, 35%, 40%, 45%, 50% or a range between any two of the above values.

[0064] In one specific embodiment provided by the present application, the solid content of the solution of the complex of the phosphorous acid-containing resin and the iron ion is preferably 35%.

[0065] In one specific embodiment provided by the present application, the mass of the flame retardant is alternatively 0.5%, 1%, 3%, 5%, 8%, 10%, 11%, 13%, 15%, 18%, 20% or a range between any two of the above values of the mass of the flame-retardant coating.

[0066] The addition of the amino silane coupling agent to the flame-retardant coating can increase the content of nitrogen in the flame-retardant coating and improve the compatibility of the components; in one specific embodiment provided by the present application, the amino silane coupling agent is preferably γ-aminopropyl triethoxysilane and / or γ-aminoethyl aminopropyl trimethoxysilane.

[0067] In one specific embodiment provided by the present application, the mass of the amino silane coupling agent is 0.5%, 1%, 3%, 5%, 8%, 10%, 11%, 13%, 15%, 18%, 20% or any range between any two of the above values of the mass of the flame-retardant coating.

[0068] In one specific embodiment provided by the present application, the film-forming agent is preferably a polyurethane film-forming agent and / or an epoxy film-forming agent, more preferably a polyurethane film-forming agent and an epoxy film-forming agent; the polyurethane film-forming agent is of the polyester type; specifically, the polyurethane film-forming agent can be VONDIC 1672NE; the epoxy film-forming agent is preferably a modified epoxy resin film-forming agent; the epoxy equivalent weight of the epoxy film-forming agent is preferably 200-500; optionally, the epoxy equivalent weight of the epoxy film-forming agent is 200, 300, 400, 500 or any range between any two of the above values; specifically, the epoxy film-forming agent can be a bisphenol A type epoxy resin, further specifically E-51 type epoxy resin; the mass ratio of the polyurethane film-forming agent to the epoxy film-forming agent is preferably (1-5):5; optionally, the mass ratio of the polyurethane film-forming agent to the epoxy film-forming agent is 1:5, 1.5:5, 2:5, 3:5, 4:5, 5:5 or any range between any two of the above values.

[0069] In one specific embodiment provided by the present application, the mass of the film-forming agent is 60%, 62%, 64%, 65%, 66%, 68%, 70%, 72%, 74%, 75%, 76%, 78%, 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 99% or any range between any two of the above values of the mass of the flame-retardant coating.

[0070] In one specific embodiment provided by the present application, the flame-retardant coating further comprises an auxiliary agent; the mass of the auxiliary agent is preferably 0.1%-8% of the mass of the flame-retardant coating; optionally, the mass of the auxiliary agent is 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% or any range between any two of the above values of the mass of the flame-retardant coating.

[0071] In the present application, the auxiliary agent is one known to those skilled in the art that can improve certain properties of the coating, such as uniformity, in one specific embodiment provided by the present application, the auxiliary agent is preferably a wetting agent and / or a lubricant; the wetting agent is one known to those skilled in the art, without specific limitation, in the present application, it is preferably a silicone wetting agent, more preferably BYK-P9920; the lubricant is an aqueous organic silicone lubricant known to those skilled in the art, without specific limitation, in the present application, it is preferably BYK-024.

[0072] In one specific embodiment provided by the present application, the mass of the flame-retardant coating is preferably 1% to 3% of the mass of the flame-retardant glass fiber; alternatively, the mass of the flame-retardant coating is 1%, 1.5%, 2%, 2.5%, 3% of the mass of the flame-retardant glass fiber, or a range between any two of the above values.

[0073] The flame-retardant glass fiber provided by the present application has a high-efficiency flame-retardant agent with the function of rapid catalytic carbonization, and has a synergistic flame-retardant function. When used for preparing a fiber-reinforced thermoplastic composite material, it can promote the carbonization of the externally added flame-retardant agent at the interface layer between the flame-retardant glass fiber and the resin matrix, achieve a synergistic flame-retardant effect, improve the carbonization quality and efficiency to inhibit the wick effect of the fiber, improve the flame-retardant performance, reduce the amount of externally added flame-retardant agent in the granulation process, reduce the production cost while improving the mechanical properties, and has a broad application prospect in actual industrial production.

[0074] The present application also provides a preparation method of the above flame-retardant glass fiber, comprising the following steps: S1) mixing the hydrolyzed amino silane coupling agent, the film-forming agent solution and the flame-retardant agent in water to obtain an infiltration water agent; S2) coating the infiltration water agent on the surface of the glass fiber and drying to obtain the flame-retardant glass fiber.

[0075] In the present application, there is no special limitation on the source of all raw materials, which can be commercially available; the amino silane coupling agent, the film-forming agent and the flame-retardant agent are the same as described above, and will not be repeated here.

[0076] In one specific embodiment provided by the present application, the film-forming agent solution is preferably a polyurethane film-forming agent solution and / or an epoxy film-forming agent solution.

[0077] In one specific embodiment provided by the present application, the solid content of the polyurethane film-forming agent solution is preferably 48% to 50%; alternatively, the solid content of the polyurethane film-forming agent solution is 48%, 49%, 50%, or a range between any two of the above values.

[0078] In one specific embodiment provided by the present application, the viscosity of the polyurethane film-forming agent solution is preferably 100 to 1000 mpa.s. In one specific embodiment provided by the present application, the particle size of the polyurethane film-forming agent solution is preferably 200 to 500 nm.

[0079] In one specific embodiment provided by the present application, the solid content of the epoxy film-forming agent solution is preferably 58% to 62%; alternatively, the solid content of the epoxy film-forming agent solution is 58%, 59%, 60%, 61%, 62%, or a range between any two of the above values.

[0080] In one specific embodiment provided by the present application, the viscosity of the epoxy film-forming agent solution is preferably 100-3000 mpa.s.

[0081] In one specific embodiment provided by the present application, the particle size of the epoxy film-forming agent solution is preferably 200-1400 nm.

[0082] The hydrolyzed amino silane coupling agent, the film-forming agent solution and the flame retardant are mixed in water to obtain a water infiltration agent; in the present application, the following steps can be specifically followed: the amino silane coupling agent is first hydrolyzed to be clear and transparent, without oil film on the surface, and then mixed with other components; the mixing method is well known to those skilled in the art and is not particularly limited; the solid content of the water infiltration agent is preferably 5%-20%; alternatively, the solid content of the water infiltration agent is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or a range between any two of the above values.

[0083] The water infiltration agent is coated on the surface of the glass fiber; the coating method is well known to those skilled in the art and is not particularly limited, and in the present application, roll coating is preferred; the linear speed of roll coating is preferably 10-20 m / min; alternatively, the linear speed of roll coating is 10 m / min, 11 m / min, 12 m / min, 13 m / min, 14 m / min, 15 m / min, 16 m / min, 17 m / min, 18 m / min, 19 m / min, 20 m / min or a range between any two of the above values.

[0084] After coating, short cutting is preferably performed, and then drying is performed to obtain the flame-retardant glass fiber; the length of the short cutting is preferably 2-5 mm; alternatively, the length of the short cutting is 2 mm, 3 mm, 4 mm, 5 mm or a range between any two of the above values; the drying temperature is preferably 150°C-200°C; alternatively, the drying temperature is 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or a range between any two of the above values; the drying time is preferably 5-10 min; alternatively, the drying time is 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or a range between any two of the above values; the moisture content of the flame-retardant glass fiber is preferably less than 0.05%.

[0085] The preparation method of the flame-retardant glass fiber provided by the present application is simple, the production process is easy to control and suitable for large-scale production. The prepared flame-retardant glass fiber does not contain halogen and meets the environmental protection standard. When it is used to reinforce thermoplastic resin, it exhibits excellent flame-retardant effect and mechanical properties, indicating great application potential in the industrial field.

[0086] The present application also provides a fiber reinforced thermoplastic composite material comprising the above-mentioned flame-retardant glass fiber and a thermoplastic resin. The function of the flame-retardant coating of the flame-retardant glass fiber mainly includes providing efficient catalytic charring flame retardation, protecting the glass fiber from forming bundles, and improving the compatibility of the glass fiber and the resin interface.

[0087] In a specific embodiment provided by the present application, the mass of the flame-retardant glass fiber is preferably 10% to 40% of the mass of the fiber reinforced thermoplastic composite material; alternatively, the mass of the flame-retardant glass fiber is 10%, 15%, 20%, 25%, 30%, 35%, 40% of the mass of the fiber reinforced thermoplastic composite material, or a range between any two of the above-mentioned values.

[0088] In a specific embodiment provided by the present application, the thermoplastic resin can be any thermoplastic resin known to those skilled in the art, and is not particularly limited, including but not limited to PBT resin and / or PA resin.

[0089] In a specific embodiment provided by the present application, the fiber reinforced thermoplastic composite material preferably further comprises an additional flame retardant; the mass of the additional flame retardant is preferably 5% to 20% of the mass of the fiber reinforced thermoplastic composite material; alternatively, the mass of the additional flame retardant is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% of the mass of the fiber reinforced thermoplastic composite material, or a range between any two of the above-mentioned values; the type of the additional flame retardant is preferably an aluminum organophosphonate flame retardant; in the embodiments provided by the present application, Clariant Exolit OP1240 is specifically used as an example.

[0090] In a specific embodiment provided by the present application, the fiber reinforced thermoplastic composite material preferably further comprises an additional additive; the mass of the additional additive is preferably 0.1% to 5% of the mass of the fiber reinforced thermoplastic composite material; alternatively, the mass of the additional flame retardant is 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% of the mass of the fiber reinforced thermoplastic composite material, or a range between any two of the above-mentioned values; the additional additive is preferably an antioxidant; the type of the antioxidant is preferably a hindered phenol antioxidant.

[0091] In a specific embodiment provided by the present application, the fiber reinforced thermoplastic composite material is preferably obtained by extrusion granulation; the temperature of the extrusion granulation can be selected according to the type of the thermoplastic resin, and specifically can be 220°C to 250°C.

[0092] In order to further illustrate the present application, the following examples provide a kind of flame-retardant glass fiber and its preparation method and fiber reinforced thermoplastic composite material provided by the present application in detail.

[0093] The reagents used in the following examples are all commercially available; the PEI used in the examples has a molecular weight of 300-600 g / mol.

[0094] Preparation of PEIP-Fe: First, dissolve PEI in deionized water and stir evenly to obtain 300 mL of PEI solution with a concentration of 7 wt%. Then slowly add 100 mL of phosphorous acid solution with a mass fraction of 20 t% to the flask under stirring at 800 rpm, stir evenly, then slowly add 20 g of formaldehyde solution with a mass concentration of 37%, and mix the solution at 110°C for 4 h under rapid stirring. Finally, slowly add 1.55 g of 20 wt% iron nitrate solution, stir for 2 h, and finally adjust the pH to about 7 with ammonia water to obtain the PEIP-Fe solution.

[0095] Preparation of ATMP-Fe: First, dissolve ATMP in deionized water and stir evenly to obtain a 20 wt% ATMP solution. Then slowly add 2 g of 20 wt% iron nitrate solution to 200 mL of ATMP solution, heat and stir at 80°C for 2 h until completely dissolved, and finally adjust the pH to about 7 with ammonia water to obtain the ATMP-Fe solution.

[0096] Example 1

[0097] S1) Preparation of the water-based sizing agent:

[0098] The coupling agent, film-forming agent, high-efficiency catalytic flame retardant, and other additives are weighed according to the formula, diluted with water in sequence, and then added to prepare the water-based sizing agent. The coupling agent is A1100 (γ-aminopropyl triethoxysilane coupling agent), which needs to be hydrolyzed to be clear and transparent without an oil film on the surface. The preferred amount of the coupling agent in the formula is 10% (based on the dry mass). The film-forming agent used includes two types: polyurethane film-forming agent (VONDIC 1672NE) and epoxy film-forming agent (E-51 type), with the preferred amount of the epoxy film-forming agent in the formula being 50% (based on the dry mass) and the preferred amount of the polyurethane film-forming agent in the formula being 30% (based on the dry mass). The high-efficiency flame retardant catalyst is PEIP-Fe, with a solid content of 35%, and the preferred amount of PEIP-Fe in the formula is 5% (based on the dry mass). The wetting agent used is BYK-P9920, and the preferred amount of BYK-P9920 in the formula is 5% (based on the dry mass). The solid content of the entire water-based sizing agent is 10%.

[0099] S2) Preparation of flame-retardant glass fiber:

[0100] The infiltrating agent is evenly coated on the surface of the glass fiber filaments by roller coating, and then the glass fiber filaments are cut and dried to prepare the finished flame-retardant glass fiber product. The roller coating line speed is 16 m / min, the drying temperature is preferably 190°C, the cutting length is 4.5 mm, the diameter is 10-11 microns, and the drying time is 7 min. The dry matter content of the infiltrating agent coated on the surface of the glass fiber filaments obtained after drying is 1%-2% (as shown in Table 1), and the moisture content of the finished flame-retardant glass fiber product is less than 0.05%.

[0101] S3) Preparation of flame-retardant glass fiber reinforced PBT resin composite:

[0102] The prepared flame-retardant glass fiber and PBT resin (BASF, B4520), flame retardant (Exolit OP1240) are granulated by a double screw extruder, and the granulation formula is as follows: the content of PBT resin is 53.7-57.7 wt% (making the total amount 100%), the content of flame-retardant glass fiber is 30 wt%, the content of added flame retardant is shown in Table 1, and the content of antioxidant (1010) is 0.3%; the proportions of resin, flame retardant, and additives are accurately weighed, and the materials are mixed for 3 min by high-speed mixing. The flame-retardant glass fiber and the mixed materials are extruded and granulated by a double screw, and the processing temperature is 220°C-250°C. After granulation, the materials are placed in an oven for annealing and drying. Then, according to the standard, standard samples are injection molded, and the flame-retardant performance and mechanical properties are tested according to the relevant standards, and the results are shown in Table 1.

[0103] Example 2

[0104] The difference from Example 1 is that the content of polyurethane film-forming agent in the formula is 25% (by dry matter mass), and the content of high-efficiency flame-retardant catalyst PEIP-Fe in the formula is 10% (by dry matter mass).

[0105] Example 3

[0106] The difference from Example 1 is that the content of high-efficiency flame-retardant catalyst PEIP-Fe in the formula is 20% (by dry matter mass), and the content of PEIP-Fe in the formula is 15% (by dry matter mass).

[0107] Example 4

[0108] The difference from Example 1 is that the content of high-efficiency flame-retardant catalyst PEIP-Fe in the formula is 15% (by dry matter mass), and the content of PEIP-Fe in the formula is 20% (by dry matter mass).

[0109] Example 5

[0110] The difference from Example 1 is that the efficient flame retardant catalyst is ATMP-Fe, which is used in the formula at a proportion of 5% (by dry matter mass).

[0111] Example 6

[0112] The difference from Example 2 is that the efficient flame retardant catalyst is ATMP-Fe, which is used in the formula at a proportion of 10% (by dry matter mass).

[0113] Example 7

[0114] The difference from Example 3 is that the efficient flame retardant catalyst is ATMP-Fe, which is used in the formula at a proportion of 15% (by dry matter mass).

[0115] Example 8

[0116] The difference from Example 4 is that the efficient flame retardant catalyst is ATMP-Fe, which is used in the formula at a proportion of 20% (by dry matter mass).

[0117] Comparative Example 1

[0118] The normal commercially available chopped glass fiber product (CPIC, ECS303-4.5-H / ECT) for reinforced PBT resin was used to prepare the fiber-reinforced PBT resin composite according to the method of Example 1.

[0119] Comparative Example 2

[0120] The difference from Example 1 is that no efficient catalytic flame retardant is added, which is a blank control sample.

[0121] The tensile strength test standard is GB / T 1040.1-2018; the bending strength test standard is GB T9341-2008; and the cantilever beam impact strength test standard is GB / T1843-2008.

[0122] Flame Retardant Performance Test: The test was carried out according to the UL94 flame retardant test standard commonly used in the industry. The flame-retardant sample was prepared by injection molding, and the surface was required to be smooth, without burr, and the density was uniform. The sample size was (125±5) x (13.0±0.5) x thickness (thickness 0.8mm, 1.6mm). The sample was at least two sets, and each set had 5 samples. The test was carried out according to the UL94 flame retardant performance test method. After burning for 10±0.5 seconds, the afterflame time t1 was recorded. After the afterflame stopped, the sample was burned again for 10±0.5 seconds. The afterflame time t2 and afterburning time t3 were recorded. Whether the sample was burned out or not was recorded. Whether the dripping material ignited the cotton during the test was recorded. Flame Retardant Performance Determination: V-0 level: single sample t1 / t2≤10s, all samples t1+t2≤50s, single sample t2+t3≤30s, not burned out, and not ignited cotton; V-1 level: single sample t1 / t2≤30s, all samples t1+t2≤250s, single sample t2+t3≤60s, not burned out, and not ignited cotton; V-2 level: single sample t1 / t2≤30s, all samples t1+t2≤250s, single sample t2+t3≤60s, not burned out, and ignited cotton.

[0123] Table 1 Performance test results of fiber reinforced PBT resin composite

[0124]

[0125]

[0126] From the above test results, it can be seen that the flame-retardant glass fiber reinforced PBT composite prepared by the method provided in the present application has excellent flame-retardant performance and mechanical properties compared with Comparative Examples 1 and 2. When PEIP-Fe is used as a catalytic flame retardant and the addition amount is 15%, 0.8mm V0 level can be achieved. When ATMP-Fe is used as a catalytic flame retardant and the addition amount is 20%, 0.8mm V0 level can be achieved. However, when a normal commercially available chopped yarn product is used, the addition amount of flame retardant needs to reach 16wt% to achieve V0, which can reduce the addition amount of flame retardant by more than 20wt%. This shows that the flame-retardant coating containing a catalytic flame retardant provided in the present application has obvious effect on improving flame-retardant performance, and PEIP-Fe has better flame-retardant performance. In terms of mechanical properties, ATMP-Fe as a catalytic flame retardant has better mechanical properties than Comparative Examples and PEIP-Fe samples, which shows that the interfacial compatibility of PEIP-Fe is worse than that of ATMP-Fe. Comprehensive analysis of Examples 3 and 8 shows that the flame-retardant performance is the best, and the comprehensive mechanical properties of Example 8 are more excellent.

[0127] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.

Claims

1. A flame retardant glass fiber, characterized in that, The application relates to a fire-retardant glass fiber, which comprises the following components: glass fiber and a fire-retardant coating attached to the surface of the glass fiber; the fire-retardant coating comprises fire-retardant agent, amino silane coupling agent and film forming agent; the fire-retardant agent is selected from the complex of phosphinic compound and iron ion and / or the complex of phosphite grafted resin and iron ion; the mass of the fire-retardant agent is 0.5%-20% of the mass of the fire-retardant coating; the mass of the amino silane coupling agent is 0.5%-20% of the mass of the fire-retardant coating; the mass of the film forming agent is 60%-99% of the mass of the fire-retardant coating; the content of iron ion in the fire-retardant agent is 1-3 wt%; the phosphinic compound is selected from one or more of aminotrimethylene phosphonic acid, ethylenediamine tetramethylene phosphonic acid, diethylene triamine pentamethylene phosphonic acid and hydroxy ethylene diphosphonic acid; the phosphite grafted resin is selected from polyethylene imine grafted with phosphite; the molecular weight of the polyethylene imine in the polyethylene imine grafted with phosphite is 300-600 g / mol; the amino silane coupling agent is selected from gamma-aminopropyl triethoxysilane and / or gamma-aminethyl aminopropyl trimethoxysilane; the film forming agent is selected from polyurethane film forming agent and / or epoxy film forming agent; the fire-retardant coating further comprises auxiliary agent, and the mass of the auxiliary agent is 0.1%-8% of the mass of the fire-retardant coating. The complex of phosphinic compound and iron ion is prepared by mixing the aqueous solution of phosphinic compound and the solution of iron salt, and then adjusting the pH value of the system to neutral to obtain the solution containing the complex of phosphinic compound and iron ion; the complex of phosphite grafted resin and iron ion is prepared by mixing the solution of resin and the solution of phosphite, then adding the solution of formaldehyde, mixing, adding the solution of iron salt, mixing, and finally adjusting the pH value of the system to neutral to obtain the solution containing the complex of phosphite grafted resin and iron ion. The mass ratio of the polyurethane film forming agent to the epoxy film forming agent is (1-5):5; the polyurethane film forming agent is selected from polyester type polyurethane film forming agent; the epoxy film forming agent is selected from modified epoxy film forming agent; the epoxy equivalent of the epoxy film forming agent is 200-500; the auxiliary agent is selected from wetting agent and / or lubricant. The mass of the fire-retardant coating is 1%-3% of the mass of the fire-retardant glass fiber. The application further relates to a preparation method of the fire-retardant glass fiber, which comprises the following steps: S1) mixing the hydrolyzed amino silane coupling agent, the solution of film forming agent and the fire-retardant agent in water to obtain the infiltration water agent; S2) coating the infiltration water agent on the surface of the glass fiber and drying to obtain the fire-retardant glass fiber. The solution of film forming agent is selected from the solution of polyurethane film forming agent and / or the solution of epoxy film forming agent; the solid content of the solution of polyurethane film forming agent is preferably 48%-50%; the viscosity of the solution of polyurethane film forming agent is 100-1000 mpa.s; the particle size of the solution of polyurethane film forming agent is 200-500 nm; the solid content of the solution of epoxy film forming agent is 58%-62%; the viscosity of the solution of epoxy film forming agent is 100-3000 mpa.s.

2. The flame retardant glass fiber of claim 1, wherein, ​ ​ ​ 3. The flame retardant glass fiber of claim 2, wherein, ​ ​ ​ ​ 4. The flame retardant glass fiber of claim 1, wherein, ​ ​ 5. The flame retardant glass fiber of claim 4, wherein, ​ ​ ​ ​ 6. The flame retardant glass fiber of claim 1, wherein, ​ 7. A process for the production of the flame retardant glass fiber of claim 1, characterized in that, ​ ​ ​ 8. The preparation method according to claim 7, characterized in that, ​ ​ ​ ​ ​ ​ The particle size of the epoxy film-forming agent solution is 200-1400 nm.

9. The preparation method according to claim 7, characterized in that, The solid content of the infiltrating water agent is 5%-20%; The moisture of the flame-retardant glass fiber is less than 0.05%. The method of coating in step S2) is roller coating, and the linear speed of the roller coating is 10-20 m / min.

10. A fiber-reinforced thermoplastic composite material, characterized by, The flame-retardant glass fiber of any one of claims 1-6 or prepared by the preparation method of any one of claims 7-9 and a thermoplastic resin.

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