A flame retardant toughened modified phenolic resin film and preparation method thereof

Abstract

The invention belongs to the technical field of polymer materials, and provides a flame retardant toughened modified phenolic resin film and a preparation method thereof. The material composition at least comprises, by mass: 50-90 parts of phenolic resin, 10-50 parts of benzoxazine resin, 50-100 parts of polyvinyl butyral, 10-30 parts of reactive phosphorus flame retardant, and 5-10 parts of synergistic flame retardant; firstly, polyvinyl butyral is dissolved with anhydrous ethanol, and then the phenolic resin, benzoxazine resin, reactive phosphorus flame retardant and synergistic flame retardant are added, the mixed liquid is fully stirred and dissolved, and mixed evenly, and a flame retardant toughened modified phenolic resin film is prepared by a coating process. The microstructure of the film presents multi-scale, multi-level toughening and flame retardancy, and the toughening and flame retardancy effects of the phenolic resin are both taken into consideration. The method is suitable for mass production and is suitable for the fields of ship protective armor, lining armor, high temperature resistant bonding materials, corrosion resistant materials, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, relates to a modified phenolic resin preparation technology, and specifically relates to a flame retardant toughened modified phenolic resin film and a preparation method thereof. Background Art

[0002] Phenolic resin (PF) has the characteristics of low price, electrical insulation, low toxicity and smoke, good bonding performance, etc., and is widely used in armor protection, vehicle engineering, aerospace and other fields. However, traditional phenolic resin is relatively brittle, with low toughness and tensile strength, and has the disadvantages of low interlaminar strength and weak anti-delamination and impact resistance. Although the oxygen index of phenolic resin is about 28%, it still cannot meet the flame retardant requirements in occasions with strict requirements on low smoke flame retardant properties of materials, such as ship protection, aerospace and other fields, which limits its further wide application.

[0003] Zhang Liqing (Heat resistance and toughening properties of polyvinyl butyral modified phenolic resin [J]. Polymer Materials Science and Engineering, 2021, (37) 6: 85-93.) and other researchers have conducted research on the toughening modification of phenolic resin by physical blending or chemical synthesis. Among them, polyvinyl butyral (PVB) is the most widely used toughening agent for phenolic resin. Since the oxygen index of PVB is only about 17%, the flame retardancy is significantly reduced after toughening modification.

[0004] Guo Jintang et al. (Research on flame retardancy and toughening of phenolic resin [J]. Combustion Science and Technology, 2003, (9) 2: 104-107.) In the synthesis of phenolic resin, by adding nonylphenol to partially replace phenol, the toughness of phenolic foam can be significantly increased while the flame retardant properties remain basically unchanged.

[0005] None of the above solves the problem that phenolic resin has both high toughness and high flame retardancy. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a flame retardant toughened modified phenolic resin film and a preparation method thereof, thereby solving the problem that phenolic resin is difficult to achieve both high toughness and high flame retardancy.

[0007] The object of the present invention is achieved in the following ways: polyvinyl butyral (PVB) is used as a modifier, and when the modified phenolic resin is heated and cured, the hydroxymethyl in the phenolic resin molecule and the hydroxyl in the PVB molecule undergo a dehydration condensation reaction to obtain a PVB-phenolic resin graft copolymer, thereby reducing the network density of the phenolic resin and improving its toughness; a phosphorus-based flame retardant is used to react chemically with the phenolic resin, and a molecular segment or structure with flame retardant performance is introduced into the synthesis of the phenolic resin to give it permanent flame retardant performance; a synergistic flame retardant is used that can not only react with the phenolic resin, but also significantly helps to improve the combustion rate of the phenolic resin; benzoxazine resin and phenolic resin can serve as curing agents for each other, and after the benzoxazine resin is ring-opened, it can form a Mannich bridge structure with the phenolic hydroxyl group of the linear phenolic resin to increase the toughness of the phenolic resin system, and at the same time, due to the formation of a complex cross-linked network structure, the flame retardancy and heat resistance of the system are improved.

[0008] The specific technical solution adopted by the present invention is as follows:

[0009] A flame retardant toughened modified phenolic resin film, the material composition at least includes, by mass:

[0010]

[0011] The total amount of the phenolic resin and the benzoxazine resin is 100 parts by mass.

[0012] The invention relates to a flame retardant toughened modified phenolic resin film, wherein the phenolic resin is a liquid alkali catalyzed phenolic resin.

[0013] Preferably, the liquid alkali-catalyzed phenolic resin is one of S157 and PF9601.

[0014] The invention relates to a flame retardant toughened modified phenolic resin film, wherein the benzoxazine resin is a liquid benzoxazine resin.

[0015] Preferably, the liquid benzoxazine resin is one of bisphenol F-type benzoxazine resins LZ96 and LZ24.

[0016] Preferably, the reactive phosphorus-based flame retardant is 10-(2,5-dihydroxyphenyl)-10-hydrogen-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ) and / or [(6-oxo-(6H)-dibenzo-(CE)(1,2)-oxaphosphahexane-6-one)methyl]-succinic acid (DOPO-DDP).

[0017] Preferably, the synergistic flame retardant is tannic acid and / or hydroxyethylidene diphosphonic acid (HEDP).

[0018] The present invention relates to a method for preparing a flame retardant toughened modified phenolic resin film, and the specific steps are as follows:

[0019] 1) Weigh various materials according to the formula ratio, dissolve the toughening agent polyvinyl butyral in anhydrous ethanol, the mass ratio of the toughening agent to anhydrous ethanol is 1:8-1:12, and stir thoroughly until the mixed solution is uniform and transparent;

[0020] 2) adding phenolic resin and benzoxazine resin to the solution in step 1), and continuing to stir until the mixture is uniform;

[0021] 3) adding a reactive phosphorus-based flame retardant and a synergistic flame retardant to the solution of step 2), and continuing to stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution;

[0022] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate, with a coating surface density of no less than 1kg / m 2 , dry under ventilation at room temperature for not less than 4 hours, then pre-cure at 80-100°C for 10-30 minutes, cool and peel off to obtain a flame retardant toughened modified phenolic resin film.

[0023] The flame retardant toughened modified phenolic resin film involved in the present invention has a peel strength of 12 to 20 N / cm with a smooth stainless steel plate; after being fully cured, compared with pure phenolic resin, the maximum deflection is increased by 70%, and the toughness of the phenolic resin is significantly improved; the oxygen index is not less than 30%, and the flame retardancy is significantly improved; it can be used in the fields of ship protective armor, lining armor, high temperature resistant bonding materials, corrosion resistant materials, etc.

[0024] To prepare the above-mentioned phenolic resin film, firstly, an appropriate amount of toughening agent polyvinyl butyral is dissolved in anhydrous ethanol, and then a certain proportion of phenolic resin, benzoxazine resin, reactive phosphorus flame retardant and synergistic flame retardant are added, and the above-mentioned mixed liquid is fully stirred to dissolve and mix evenly, and an uncrosslinked and cured film is obtained through a coating process, and the pre-curing cross-linking degree of the pre-curing temperature control system is controlled so that the microstructure presents multi-scale, multi-level toughening and flame retardancy, thereby achieving a balance between toughening and flame retardancy of phenolic resin. This method is suitable for mass production. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the embodiments, but the technical solution of the present invention is not limited to the specific implementation methods listed below. Those skilled in the art may make some non-essential changes and adjustments based on the content of the above invention, which all belong to the protection scope of the present invention.

[0026] Embodiment 1

[0027] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0028] 50 parts of S157 phenolic resin, 50 parts of LZ96 benzoxazine resin, 50 parts of polyvinyl butyral (PVB) toughening agent, 10 parts of reactive phosphorus flame retardant DOPO-HQ, and 5 parts of synergistic flame retardant tannic acid.

[0029] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0030] 1) Weigh 50 parts of polyvinyl butyral (PVB), dissolve it in 400 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0031] 2) Weigh 50 parts of S157 phenolic resin and 50 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0032] 3) Weigh 10 parts of DOPO-HQ and 5 parts of tannic acid in sequence, add them to the solution in step 2), stir thoroughly until the mixture is uniform, and prepare a modified phenolic resin mixed solution;

[0033] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1 kg / m 2 , dried under ventilation at room temperature for 4 hours, then pre-cured at 80°C for 35 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0034] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.32 mm, and has a peel strength of 15.9 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 32.2%, and the maximum deflection is 19.5 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0035] Embodiment 2

[0036] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0037] 62 parts of S157 phenolic resin, 38 parts of LZ24 benzoxazine resin, 60 parts of polyvinyl butyral (PVB) toughening agent, 20 parts of reactive phosphorus flame retardant DOPO-HQ, and 7 parts of synergistic flame retardant tannic acid.

[0038] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0039] 1) Weigh 60 parts of polyvinyl butyral (PVB), dissolve it in 500 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0040] 2) Weigh 62 parts of S157 phenolic resin and 38 parts of LZ24 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0041] 3) Weigh 20 parts of DOPO-HQ and 7 parts of tannic acid in sequence, add them to the solution in step 2), stir thoroughly until the mixture is uniform, and prepare a modified phenolic resin mixed solution;

[0042] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.1 kg / m 2 , dried under ventilation at room temperature for 5 hours, then pre-cured at 90°C for 20 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0043] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.33 mm, and has a peel strength of 13.8 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 33.4%, and the maximum deflection is 14.7 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0044] Embodiment 3

[0045] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0046] 58 parts of PF9601 phenolic resin, 42 parts of LZ96 benzoxazine resin, 64 parts of polyvinyl butyral (PVB) toughening agent, 10 parts of reactive phosphorus flame retardant DOPO-DDP, and 5 parts of synergistic flame retardant HEDP.

[0047] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0048] 1) Weigh 64 parts of polyvinyl butyral (PVB), dissolve it in 600 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0049] 2) Weigh 58 parts of PF9601 phenolic resin and 42 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0050] 3) Weigh 10 parts of DOPO-DDP and 5 parts of HEDP in sequence, add them to the solution in step 2), stir thoroughly until the mixture is uniform, and prepare a modified phenolic resin mixed solution;

[0051] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.1 kg / m 2, ventilated and dried at room temperature for 6.5 hours, then pre-cured at 85°C for 25 minutes, cooled and peeled off, to obtain a flame retardant toughened modified phenolic resin film.

[0052] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.32 mm, and has a peel strength of 20 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 31.2%, and the maximum deflection is 21.5 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0053] Embodiment 4

[0054] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0055] PF9601 phenolic resin 77 parts, LZ96 benzoxazine resin 23 parts, polyvinyl butyral (PVB) toughening agent 90 parts, reactive phosphorus flame retardant DOPO-HQ 15 parts, DOPO-DDP 5 parts, synergistic flame retardant tannic acid 10 parts.

[0056] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0057] 1) Weigh 90 parts of polyvinyl butyral (PVB), dissolve it in 1000 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0058] 2) Weigh 77 parts of PF9601 phenolic resin and 23 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0059] 3) Weigh 15 parts of DOPO-HQ, 5 parts of DOPO-DDP, and 5 parts of tannic acid in sequence, add them to the solution in step 2), and stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution;

[0060] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.3 kg / m 2 , dried under ventilation at room temperature for 5.5 hours, then pre-cured at 90°C for 20 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0061] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.25 mm, and has a peel strength of 14.7 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 34.1%, and the maximum deflection is 17.4 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0062] Embodiment 5

[0063] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0064] 90 parts of PF9601 phenolic resin, 10 parts of LZ24 benzoxazine resin, 100 parts of polyvinyl butyral (PVB) toughening agent, 15 parts of reactive phosphorus flame retardant DOPO-HQ, 15 parts of DOPO-DDP, 5 parts of synergistic flame retardant tannic acid, 5 parts of HEDP.

[0065] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0066] 1) Weigh 100 parts of polyvinyl butyral (PVB), dissolve it in 1200 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0067] 2) Weigh 90 parts of PF9601 phenolic resin and 10 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0068] 3) Weigh 15 parts of DOPO-HQ, 15 parts of DOPO-DDP, 5 parts of tannic acid, and 5 parts of HEDP in sequence, add them to the solution in step 2), and stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution;

[0069] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.2 kg / m 2 , dried under ventilation at room temperature for 5 hours, then pre-cured at 100°C for 15 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0070] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.23 mm, and has a peel strength of 13.4 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 30.5%, and the maximum deflection is 14.9 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0071] Embodiment 6

[0072] A flame retardant toughened modified phenolic resin film, the material composition is, by weight:

[0073] PF9601 phenolic resin 65 parts, LZ24 benzoxazine resin 35 parts, polyvinyl butyral (PVB) toughening agent 80 parts, reactive phosphorus flame retardant DOPO-DDP 30 parts, synergistic flame retardant tannic acid 5 parts.

[0074] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0075] 1) Weigh 80 parts of polyvinyl butyral (PVB), dissolve it in 800 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0076] 2) Weigh 65 parts of PF9601 phenolic resin and 35 parts of LZ24 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0077] 3) Weigh 30 parts of DOPO-DDP and 5 parts of tannic acid in sequence, add them to the solution in step 2), stir thoroughly until the mixture is uniform, and prepare a modified phenolic resin mixed solution;

[0078] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.4 kg / m 2 , dried under ventilation at room temperature for 7.5 hours, then pre-cured at 85°C for 30 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0079] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.33 mm, and has a peel strength of 17.1 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 34.8%, and the maximum deflection is 17.8 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0080] Embodiment 7

[0081] A flame retardant toughened modified phenolic resin film, the material composition is, by weight:

[0082] 80 parts of S157 phenolic resin, 20 parts of LZ96 benzoxazine resin, 80 parts of polyvinyl butyral (PVB) toughening agent, 5 parts of reactive phosphorus flame retardant DOPO-HQ, 15 parts of DOPO-DDP, and 8 parts of synergistic flame retardant HEDP.

[0083] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0084] 1) Weigh 80 parts of polyvinyl butyral (PVB), dissolve it in 900 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0085] 2) Weigh 80 parts of S157 phenolic resin and 20 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0086] 3) Weigh 5 parts of DOPO-HQ, 15 parts of DOPO-DDP, and 5 parts of HEDP in sequence, add them to the solution in step 2), and stir them thoroughly until they are evenly mixed to obtain a modified phenolic resin mixed solution;

[0087] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.3 kg / m 2 , ventilated and dried at room temperature for 6 hours, then pre-cured at 85°C for 25 minutes, cooled and peeled off, to obtain a flame retardant toughened modified phenolic resin film.

[0088] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.26 mm, and a peel strength between the film and a smooth stainless steel plate of 14.0 N / cm. After the resin film is heated and cured, the limiting oxygen index of the material is 33.5%, and the maximum deflection is 16.8 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0089] Embodiment 8

[0090] A flame retardant toughened modified phenolic resin film, the material composition of which is, by mass: 60 parts of PF9601 phenolic resin, 40 parts of LZ24 benzoxazine resin, 70 parts of polyvinyl butyral (PVB) toughening agent, 20 parts of reactive phosphorus flame retardant DOPO-DDP, 3 parts of synergistic flame retardant tannic acid, and 7 parts of HEDP.

[0091] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0092] 1) Weigh 70 parts of polyvinyl butyral (PVB), dissolve it in 650 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0093] 2) Weigh 60 parts of PF9601 phenolic resin and 40 parts of LZ24 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0094] 3) weighing 20 parts of DOPO-DDP, 3 parts of tannic acid, and 7 parts of HEDP in sequence, adding them to the solution in step 2), stirring them thoroughly until they are evenly mixed, to obtain a modified phenolic resin mixed solution;

[0095] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.6 kg / m 2 , ventilated and dried at room temperature for 8 hours, then pre-cured at 95°C for 20 minutes, cooled and peeled off, to obtain a flame retardant toughened modified phenolic resin film.

[0096] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.39 mm, and has a peel strength of 14.5 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 33.0%, and the maximum deflection is 18.5 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0097] Embodiment 9

[0098] A flame retardant toughened modified phenolic resin film comprises, by weight: 90 parts of S157 phenolic resin, 10 parts of LZ24 benzoxazine resin, 90 parts of polyvinyl butyral (PVB) toughening agent, 10 parts of reactive phosphorus flame retardants DOPO-HQ and 10 parts of DOPO-DDP, and 10 parts of synergistic flame retardant HEDP.

[0099] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0100] 1) Weigh 90 parts of polyvinyl butyral (PVB), dissolve it in 1080 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0101] 2) Weigh 90 parts of S157 phenolic resin and 10 parts of LZ24 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0102] 3) Weigh 10 parts of DOPO-HQ, 10 parts of DOPO-DDP, and 10 parts of HEDP in sequence, add them to the solution in step 2), and stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution;

[0103] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.4 kg / m 2 , dried under ventilation at room temperature for 5.5 hours, then pre-cured at 95°C for 15 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0104] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.27 mm, and a peel strength between the film and a smooth stainless steel plate of 12 N / cm. After the resin film is heated and cured, the limiting oxygen index of the material is 31.3%, and the maximum deflection is 16 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

[0105] Embodiment 10

[0106] A flame retardant toughened modified phenolic resin film, the material composition is, by mass:

[0107] 72 parts of S157 phenolic resin, 28 parts of LZ96 benzoxazine resin, 70 parts of polyvinyl butyral (PVB) toughening agent, 30 parts of reactive phosphorus flame retardant DOPO-HQ, 5 parts of synergistic flame retardant tannic acid, and 5 parts of HEDP.

[0108] A method for preparing a flame retardant toughened modified phenolic resin film, the specific steps are as follows:

[0109] 1) Weigh 70 parts of polyvinyl butyral (PVB), dissolve it in 700 parts of anhydrous ethanol, and stir thoroughly until the solution is uniform and transparent;

[0110] 2) Weigh 72 parts of S157 phenolic resin and 28 parts of LZ96 benzoxazine resin, add them to the solution in step 1), and stir thoroughly until the mixture is uniform;

[0111] 3) Weigh 30 parts of DOPO-HQ, 5 parts of tannic acid, and 5 parts of HEDP in sequence, add them to the solution in step 2), and stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution;

[0112] 4) Apply the modified phenolic resin mixture evenly on a smooth stainless steel plate with a coating surface density of 1.2 kg / m 2 , dried under ventilation at room temperature for 6 hours, then pre-cured at 100°C for 10 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

[0113] The flame retardant toughened modified phenolic resin film prepared in this embodiment is stable under room temperature storage conditions, is a ginger yellow soft elastic film, has a film thickness of 0.30 mm, and has a peel strength of 15.9 N / cm between the film and a smooth stainless steel plate. After the resin film is heated and cured, the limiting oxygen index of the material is 34.3%, and the maximum deflection is 17.4 mm (the maximum deflection of pure phenolic resin is 8.6 mm).

Claims

1. A flame retardant toughened modified phenolic resin film, characterized in that: The material composition shall at least include, by mass: The sum of the phenolic resin and the benzoxazine resin is 100 parts by mass; the phenolic resin is a liquid alkali-catalyzed phenolic resin; and the benzoxazine resin is a liquid benzoxazine resin; The reactive phosphorus-based flame retardant is one of DOPO-HQ and DOPO-DDP or a mixture of the two; the synergistic flame retardant is one of tannic acid and HEDP or a mixture of the two.

2. The flame retardant toughened modified phenolic resin film according to claim 1, characterized in that: The liquid alkali-catalyzed phenolic resin is one of S157 and PF9601.

3. The flame retardant toughened modified phenolic resin film according to claim 1, characterized in that: The liquid benzoxazine resin is one of bisphenol F type benzoxazine resins LZ96 and LZ24.

4. The method for preparing the flame retardant toughened modified phenolic resin film according to claim 1, characterized in that: The specific steps are as follows: 1) Weigh various materials according to the formula ratio, dissolve polyvinyl butyral in anhydrous ethanol, the mass ratio of polyvinyl butyral to anhydrous ethanol is 1:8-1:12, and stir thoroughly until the mixed solution is uniform and transparent; 2) adding phenolic resin and benzoxazine resin to the solution in step 1), and continuing to stir until the mixture is uniform; 3) adding a reactive phosphorus-based flame retardant and a synergistic flame retardant to the solution of step 2), and continuing to stir until the mixture is uniform, to obtain a modified phenolic resin mixed solution; 4) The modified phenolic resin mixture is evenly coated on a smooth stainless steel plate, dried under ventilation at room temperature for not less than 4 hours, and then pre-cured at 80-100° C. for 10-30 minutes, cooled and peeled off to obtain a flame retardant toughened modified phenolic resin film.

5. The method for preparing the flame retardant toughened modified phenolic resin film according to claim 4, characterized in that: In the step 4), the coating surface density of the modified phenolic resin mixture is not less than 1 kg / m 2 .

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