Epoxy resin adhesive modified by floating beads and modified lignin, integrated honeycomb composite material and preparation method of integrated honeycomb composite material

Abstract

The invention provides an epoxy resin adhesive modified by floating beads and modified lignin, an integrated honeycomb composite material and a preparation method of the integrated honeycomb composite material. The epoxy resin adhesive provided by the invention comprises modified lignin, the modified lignin is rich in a large amount of hydroxyl groups, phenolic hydroxyl groups and carboxyl groups, and can react with epoxy resin, so that the structure is enhanced; the epoxy resin adhesive is used for preparing the cellular board composite material, so that the cost of the material can be reduced, and the mechanical property of the composite material is enhanced; the epoxy resin adhesive is adopted, large-particle floating beads can be pressed into the non-woven fabric layer of the cellular board, the glass fiber layer, the adhesive and the cellular board non-woven fabric are connected together in a penetrating mode like rivets, and the contact area of the adhesive layer, the glass fiber layer and the cellular board non-woven fabric is increased; the density of the honeycomb composite material is smaller than or equal to 1.2 g / cm < 3 >, the horizontal tensile strength is larger than or equal to 1 MPa, and the bending strength is larger than or equal to 16 MPa.

Description

Technical Field

[0001] The present invention relates to the technical field of honeycomb composite materials, and particularly to a cenosphere, an epoxy resin adhesive modified by modified lignin, an integrated honeycomb composite material and a preparation method thereof. Background Art

[0002] Due to the lightweight, high strength, impact resistance and excellent heat insulation performance of the honeycomb panel formed by curing the adhesive, it has become a key material in modern industry and is widely used in aerospace (aircraft fuselage, satellite components, spacecraft heat insulation layer), transportation (high-speed rail carriages, new energy vehicle battery packs, ship decks), building decoration (curtain wall panels, fireproof suspended ceilings), electronic equipment (5G base station antenna covers, server chassis), industrial equipment (wind turbine nacelle covers, robot manipulators), sports equipment (rowing boat keels, snowboard core layers), military protection (bulletproof armor, electromagnetic shielding cabins) and medical equipment (CT scan bed plates, mobile field hospitals), etc., supporting the lightweight and high-performance requirements of multiple industries.

[0003] The traditional honeycomb panel manufacturing adopts a step-by-step process: first prepare the core material and the panel, and then bond them through an adhesive. The existing technology has the following problems:

[0004] 1. It is necessary to first prepare the panel board and then apply the adhesive to prepare the honeycomb composite board, resulting in a large amount of adhesive coating.

[0005] 2. The panel and the honeycomb board are cured step by step instead of being cured in one step, resulting in high energy consumption.

[0006] 3. Traditional fillers (such as calcium carbonate) increase the weight of the structure.

[0007] 4. The interface between the panel and the core material only relies on physical adhesion, and the flat tensile strength is lower than 1.0 MPa (GB / T 1452-2018), making it easy to delaminate.

[0008] The prior art discloses a structural adhesive for lightweight post-embedding of honeycomb structural plates and a preparation method thereof, which uses hollow glass microspheres (particle size < 50 μm) to reduce the density. However, the hollow glass microspheres are expensive, while cenospheres and lignin are very cheap. Cenospheres are derived from coal-fired power plant fly ash and are mainly used in lightweight concrete, heat insulation materials, coating fillers and oil drilling fluids, etc.; lignin is mainly extracted from plant cell walls and paper industry black liquor, and its applications cover multiple aspects such as wood adhesives, biofuel raw materials, polymer material additives and wastewater treatment adsorbents.

[0009] Based on the defects existing in the current honeycomb panel preparation and the used adhesive, it is necessary to make improvements. Summary of the Invention

[0010] The object of the present invention is to provide, in view of the problems and deficiencies existing in the prior art, a cenosphere, an epoxy resin adhesive modified by modified lignin, an integrated honeycomb composite material and a preparation method thereof. The honeycomb composite material prepared by the present invention can improve the mechanical properties of the honeycomb panel while maintaining the low density of the honeycomb panel composite material.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] The present invention provides an epoxy resin adhesive modified by cenosphere and modified lignin, which comprises the following components: epoxy resin, cenosphere, modified lignin;

[0013] Among them, the preparation method of the modified lignin comprises the following steps:

[0014] Mix lignin with perchloric acid solution, react at 70-80 °C for 2-3 h. After the reaction is completed, adjust the pH of the reaction system to neutral, carry out reduced pressure distillation and collect the solid precipitate to obtain modified lignin.

[0015] Preferably, the mass ratio of lignin to perchloric acid solution is 1:(10-12);

[0016] The mass fraction of the perchloric acid solution is 60-72%.

[0017] Preferably, the mass ratio of epoxy resin to cenosphere is (3-10):1;

[0018] The mass of the modified lignin is 5-15% of the mass of the epoxy resin.

[0019] Preferably, the particle size of the cenosphere is 100-250 μm;

[0020] The epoxy resin includes at least one of bisphenol A type epoxy resin and E-44 epoxy resin.

[0021] Preferably, the cenosphere is a cenosphere modified by a silane coupling agent, and the modification method of the cenosphere includes:

[0022] Add a silane coupling agent to an ethanol aqueous solution to obtain a hydrolysis solution;

[0023] Add the cenosphere to the hydrolysis solution, stir for 2-3 h, filter, wash, and dry to obtain a cenosphere modified by a silane coupling agent;

[0024] Among them, the silane coupling agent includes at least one of KH-550, KH-792, KH-602, KH-560, KH-570, KH-580, KH-590, KH-902;

[0025] The volume concentration of the ethanol aqueous solution is 75-90%;

[0026] The volume ratio of the silane coupling agent to the aqueous ethanol solution is 1:(40 - 50);

[0027] The mass of the silane coupling agent is 1 - 2% of the mass of the cenospheres.

[0028] Preferably, it further includes an auxiliary agent, and the auxiliary agent includes at least one of a curing agent, an anti-aging agent, and a flame retardant.

[0029] In a second aspect, the present invention also provides a method for preparing an integrated honeycomb composite material, including the following steps:

[0030] Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics located on the upper and lower surfaces of the honeycomb core;

[0031] Immerse the glass fiber in the epoxy resin adhesive modified by cenospheres and modified lignin to obtain an adhesive glass fiber composite material;

[0032] Stack the film skin, the adhesive glass fiber composite material, the honeycomb panel, the adhesive glass fiber composite material, and the film skin in sequence from bottom to top, and hot press and cure to obtain a honeycomb composite material.

[0033] Preferably, the process parameters controlled for the hot press curing are: the curing pressure is 0.3 - 0.6 Mpa, the temperature is 115 - 125 °C, and the time is 20 - 60 min.

[0034] Preferably, the film skin includes any one of a polyester film, a metal film, and a nylon film;

[0035] The thickness of the film skin is 12 - 500 μm;

[0036] The adhesive content loaded in the adhesive glass fiber composite material is 500 - 1000 g / m 2 ;

[0037] The thickness of the glass fiber is 0.2 - 0.4 mm;

[0038] The thickness of the honeycomb panel is 1 - 2 cm, the thickness of the honeycomb core is 1 - 2 cm, the thickness of the non-woven fabric is 0.1 - 0.2 mm, and the porosity of the non-woven fabric is 40 - 60%.

[0039] In a third aspect, the present invention also provides a honeycomb composite material prepared by using the described preparation method.

[0040] The epoxy resin adhesive modified by cenospheres, modified lignin, the integrated honeycomb composite material and the preparation method thereof according to the present invention have the following beneficial effects compared with the prior art:

[0041] 1. The epoxy resin adhesive modified by cenospheres and modified lignin of the present invention includes epoxy resin, cenospheres, and modified lignin. Specifically, the lignin is modified by perchloric acid solution; the modified lignin is rich in a large number of hydroxyl groups, phenolic hydroxyl groups, and carboxyl groups, which can react with epoxy resin to enhance the structure; the epoxy resin adhesive modified by cenospheres and modified lignin is used to prepare honeycomb panel composites, which can reduce the cost of materials and enhance the mechanical properties of the composites; when the epoxy resin adhesive modified by cenospheres and modified lignin is used, the large-particle cenospheres will be pressed into the non-woven layer of the honeycomb panel, connecting the glass fiber layer, the adhesive, and the honeycomb panel non-woven fabric together like rivets, increasing the contact area of the adhesive layer, the glass fiber layer, and the honeycomb panel non-woven fabric.

[0042] 2. The preparation method of the integrated honeycomb composite material of the present invention prepares a lightweight honeycomb composite material: the density of the composite material ≤ 1.2 g / cm 3 ; the honeycomb composite material prepared by the present invention has high strength: the flat tensile strength ≥ 1 MPa, and the bending strength ≥ 16 MPa; the preparation method of the present invention has high production efficiency: a single hot pressing replaces the traditional 4 - 6 processes, and the energy consumption is reduced by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0044] Figure 1 It is a schematic diagram of stacking a film skin, an adhesive glass fiber composite material, a honeycomb panel, an adhesive glass fiber composite material, and a film skin from bottom to top in sequence. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0046] In the description of the present invention, it should be understood that the relationships indicating orientations or positions, such as "upper", are based on the orientations or positions shown in the accompanying drawings, or the orientations or positions in which the products of the invention are customarily placed during use, or the orientations or positions commonly understood by those skilled in the art. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0047] The description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of the present application, the term "comprising" means "including but not limited to". The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0048] The embodiments of the present application provide an epoxy resin adhesive modified by cenospheres and modified lignin, comprising the following components: epoxy resin, cenospheres, modified lignin;

[0049] Among them, the preparation method of the modified lignin includes the following steps:

[0050] Mix the lignin with perchloric acid solution and react at 70 - 80 °C for 2 - 3 h. After the reaction is completed, adjust the pH of the reaction system to neutral, perform vacuum distillation and collect the solid precipitate to obtain the modified lignin.

[0051] The epoxy resin adhesive modified by cenospheres and modified lignin of the present invention comprises epoxy resin, cenospheres and modified lignin. Specifically, the lignin is modified by perchloric acid solution. The specific modification method is as follows: lignin and perchloric acid solution are stirred and mixed at room temperature (20-25°C) for 30-40 minutes, and then refluxed at 70-80°C for 2-3 hours. After the reaction is completed, the pH of the reaction system is adjusted to neutral with NaOH, and the solvent is removed by vacuum distillation and the solid precipitate is collected to obtain modified lignin. The modified lignin is rich in a large number of hydroxyl groups, phenolic hydroxyl groups and carboxyl groups, and can react with epoxy resin, thereby enhancing the structure. Using the epoxy resin adhesive modified by cenospheres and modified lignin to prepare honeycomb board composites can reduce the cost of materials and enhance the mechanical properties of the composites. Using the epoxy resin adhesive modified by cenospheres and modified lignin, the large-particle cenospheres will be pressed into the non-woven fabric layer of the honeycomb board, and penetrate and connect the glass fiber layer, adhesive and honeycomb board non-woven fabric together like rivets, increasing the contact area of the adhesive layer, glass fiber layer and honeycomb board non-woven fabric.

[0052] In some embodiments, the mass ratio of lignin to perchloric acid solution is 1:(10-12);

[0053] The mass fraction of the perchloric acid solution (specifically an aqueous solution) is 60-72%.

[0054] In some embodiments, the mass ratio of epoxy resin to cenospheres is (3-10):1;

[0055] The mass of the modified lignin is 5-15% of the mass of the epoxy resin.

[0056] In some embodiments, the particle size of the cenospheres is 100-250 μm.

[0057] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin and E-44 epoxy resin.

[0058] In some embodiments, the cenospheres are cenospheres modified by a silane coupling agent. The modification method of the cenospheres includes:

[0059] Adding a silane coupling agent to an ethanol aqueous solution to obtain a hydrolysis solution;

[0060] Adding the cenospheres to the hydrolysis solution, stirring for 2-3 hours, filtering, washing and drying to obtain the cenospheres modified by the silane coupling agent;

[0061] Among them, the silane coupling agent includes at least one of KH-550, KH-792, KH-602, KH-560, KH-570, KH-580, KH-590, KH-902;

[0062] The volume concentration of the ethanol aqueous solution is 75-90%;

[0063] The volume ratio of the silane coupling agent to the ethanol aqueous solution is 1:(40 - 50);

[0064] The mass of the silane coupling agent is 1 - 2% of the mass of the cenospheres.

[0065] In some embodiments, it further includes an auxiliary agent, and the auxiliary agent includes at least one of a curing agent, an anti-aging agent, and a flame retardant.

[0066] The preparation method of the epoxy resin adhesive modified by cenospheres and modified lignin according to the present invention is as follows: Mix epoxy resin, cenospheres, and modified lignin (if an auxiliary agent is included, add the auxiliary agent), and then the epoxy resin adhesive modified by cenospheres and modified lignin is obtained.

[0067] The epoxy resin adhesive modified by cenospheres and modified lignin according to the present invention has the following advantages compared with the prior art:

[0068] Density: Cenospheres (0.3 g / cm 3 ), modified lignin (1.3 g / cm 3 ), and the epoxy resin composite make the density of the adhesive ≤ 1.2 g / cm 3 ;

[0069] Strength: The interface flat tensile strength of the epoxy resin modified by modified lignin and the cenospheres' anchoring reaches above 1 MPa.

[0070] Based on the same inventive concept, the present invention also provides a preparation method of an integrated honeycomb composite material, including the following steps:

[0071] S1. Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics on the upper and lower surfaces of the honeycomb core;

[0072] S2. Immerse glass fibers in the epoxy resin adhesive modified by cenospheres and modified lignin to obtain an adhesive glass fiber composite material;

[0073] S3. Stack the film skin, the adhesive glass fiber composite material, the honeycomb panel, the adhesive glass fiber composite material, and the film skin in sequence from bottom to top, and hot-press and cure to obtain a honeycomb composite material.

[0074] Specifically, as shown in Figure 1 , stack the film skin 1, the adhesive glass fiber composite material 2, the honeycomb panel 3, the adhesive glass fiber composite material 2, and the film skin 1 in sequence from bottom to top, and hot-press and cure. The epoxy resin curing fuses the film skin and glass fiber interface to form.

[0075] Specifically, in some embodiments, glass fiber is impregnated in an epoxy resin adhesive modified by cenospheres and modified lignin at room temperature (20-25 °C) to obtain an epoxy resin / glass fiber composite material; wherein, the amount of epoxy resin adhesive loaded per square meter of glass fiber is 500-1000 g, that is, the loading amount is 500-1000 g / m 2 .

[0076] In some embodiments, the process parameters controlled by hot pressing and curing are: curing pressure is 0.3-0.6 Mpa, temperature is 115-125 °C, and time is 20-60 min.

[0077] In some embodiments, the film skin includes any one of polyester film, metal film, and nylon film;

[0078] In some embodiments, the thickness of the film skin is 12-500 μm.

[0079] In some embodiments, the honeycomb core is an aramid honeycomb core.

[0080] In some embodiments, the content of the adhesive loaded in the adhesive glass fiber composite material is 500-1000 g / m 2 ;

[0081] In some embodiments, the thickness of the glass fiber is 0.2-0.4 mm.

[0082] In some embodiments, the thickness of the honeycomb panel is 1-2 cm, the thickness of the honeycomb core is 1-2 cm, the thickness of the non-woven fabric is 0.1-0.2 mm, and the porosity of the non-woven fabric is 40-60%.

[0083] The honeycomb composite material prepared by the present invention comprises a three-layer collaborative design: outer layer: a film skin with a thickness of 12-500 μm, providing weather resistance protection; middle layer: impregnated glass fiber cloth, and cenospheres, modified lignin, and epoxy resin in the adhesive form a "rigid-toughness" composite system; inner layer: an aramid honeycomb core combined with a non-woven fabric surface layer (porosity 40-60%). The cenospheres in the middle layer are embedded in the non-woven fabric to form a rivet-like structure.

[0084] The preparation method of the integrated honeycomb composite material of the present invention has the following advantages:

[0085] The honeycomb composite material prepared by the present invention is lightweight: the density of the composite material ≤ 1.2 g / cm 3 ; the honeycomb composite material prepared by the present invention has high strength: the flat tensile strength ≥ 1.0 MPa (GB / T 1452-2018); the preparation method of the present invention has high production efficiency: a single hot pressing replaces the traditional 4-6 processes, and the energy consumption is reduced by 30%.

[0086] Based on the same inventive concept, the present invention also provides a honeycomb composite material, which is prepared by the above-mentioned preparation method. The following further illustrates the present application's cenospheres, epoxy resin adhesives modified with modified lignin, integrated honeycomb composite materials and their preparation methods with specific examples. This part further illustrates the content of the present invention in combination with specific examples, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well-known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0087] Example 1

[0088] The embodiment of the present application provides an epoxy resin adhesive modified with cenospheres and modified lignin, including the following components in parts by weight:

[0089] 100 parts of epoxy resin, 30 parts of KH-550 modified cenospheres, 10 parts of modified lignin;

[0090] The epoxy resin is E-44 epoxy resin (specifically EP epoxy resin E44 from Baling Petrochemical);

[0091] Among them, the preparation method of the modified lignin includes the following steps:

[0092] Mix lignin and perchloric acid solution at room temperature (25 °C) with stirring for 30 min, and then react at 80 °C for 3 h. After the reaction is completed, adjust the pH of the reaction system to neutral with NaOH, and carry out vacuum distillation and collect the solid precipitate to obtain modified lignin;

[0093] The mass ratio of lignin to perchloric acid solution is 1:10; the mass fraction of the perchloric acid solution (specifically an aqueous solution) is 65%;

[0094] The preparation method of KH-550 modified cenospheres includes the following steps:

[0095] Add the silane coupling agent KH-550 to the ethanol aqueous solution to obtain a hydrolysis solution;

[0096] Add cenospheres (the average particle size of the cenospheres is 150 μm) to the hydrolysis solution, stir for 3 h, filter, wash, and dry to obtain silane coupling agent modified cenospheres;

[0097] The volume concentration of the ethanol aqueous solution is 80%;

[0098] The volume ratio of the silane coupling agent to the ethanol aqueous solution is 1:40;

[0099] The mass of the silane coupling agent is 1% of the mass of the cenospheres.

[0100] This embodiment also provides a preparation method of an integrated honeycomb composite material, including the following steps:

[0101] S1. Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics located on the upper and lower surfaces of the honeycomb core;

[0102] S2. Immerse glass fibers in the epoxy resin adhesive modified by cenospheres and modified lignin in Example 1 at room temperature (25°C) to obtain an epoxy resin / glass fiber composite material; wherein, the epoxy resin adhesive loaded on the glass fibers per square meter is 800 g on average, that is, the loading amount is 800 g / m 2 ;

[0103] S3. Stack the film skin, the adhesive glass fiber composite material, the honeycomb panel, the adhesive glass fiber composite material, and the film skin from bottom to top in sequence, and perform hot pressing and curing to obtain a honeycomb composite material;

[0104] The process parameters controlled for hot pressing and curing are: the curing pressure is 0.5 Mpa, the temperature is 120°C, and the time is 50 min;

[0105] The film skin is a polyester film with a thickness of 0.1 mm;

[0106] The glass fibers are medium-alkali glass fiber cloth with a grammage of 1080 grams per square meter (1080 g / m 2 ), and the thickness is 0.3 mm;

[0107] The honeycomb core is an aramid honeycomb core, the thickness of the aramid honeycomb core is 1.0 cm, the thickness of the non-woven fabric is 0.1 mm, and the grammage of the non-woven fabric is 50 g / m 2 , and the porosity is 50%;

[0108] Example 2

[0109] This application embodiment provides an epoxy resin adhesive modified by cenospheres and modified lignin, including the following components in parts by weight:

[0110] 100 parts of epoxy resin, 25 parts of cenospheres modified by KH-550, and 15 parts of modified lignin;

[0111] The epoxy resin is E-44 epoxy resin (specifically EP epoxy resin E44 of Baling Petrochemical);

[0112] Among them, the preparation method of the modified lignin includes the following steps:

[0113] Stir and mix lignin with perchloric acid solution at room temperature (25°C) for 30 min, then react at 80°C for 3 h. After the reaction is completed, adjust the pH of the reaction system to neutral with NaOH, perform reduced pressure distillation and collect the solid precipitate to obtain modified lignin;

[0114] The mass ratio of lignin to perchloric acid solution is 1:10; the mass fraction of the perchloric acid solution (specifically an aqueous solution) is 65%;

[0115] A preparation method of KH-550 modified cenospheres includes the following steps:

[0116] Adding the silane coupling agent KH-550 to an ethanol aqueous solution to obtain a hydrolysis solution;

[0117] Adding cenospheres (the average particle size of the cenospheres is 150 μm) to the hydrolysis solution, stirring for 3 h, filtering, washing, and drying to obtain silane coupling agent modified cenospheres;

[0118] The volume concentration of the ethanol aqueous solution is 80%;

[0119] The volume ratio of the silane coupling agent to the ethanol aqueous solution is 1:40;

[0120] The mass of the silane coupling agent is 1% of the mass of the cenospheres.

[0121] This embodiment also provides a preparation method of an integrated honeycomb composite material, including the following steps:

[0122] S1. Providing a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics located on the upper and lower surfaces of the honeycomb core;

[0123] S2. Immersing glass fibers at room temperature (25 °C) in the epoxy resin adhesive modified by cenospheres and modified lignin in Example 2 to obtain an epoxy resin / glass fiber composite material; wherein, the amount of epoxy resin adhesive loaded per square meter of glass fibers is 800 g on average, that is, the loading amount is 800 g / m 2 ;

[0124] S3. Stacking the film skin, the adhesive glass fiber composite material, the honeycomb panel, the adhesive glass fiber composite material, and the film skin in sequence from bottom to top, and hot pressing and curing to obtain a honeycomb composite material;

[0125] The process parameters controlled for hot pressing and curing are: the curing pressure is 0.5 Mpa, the temperature is 120 °C, and the time is 50 min;

[0126] The film skin is a polyester film with a thickness of 0.1 mm;

[0127] The glass fibers are medium-alkali glass fiber cloth with a grammage of 1080 grams per square meter (1080 g / m 2 ), and the thickness is 0.3 mm;

[0128] The honeycomb core is an aramid honeycomb core, the thickness of the aramid honeycomb core is 1.0 cm, the thickness of the non-woven fabric is 0.1 mm, and the grammage of the non-woven fabric is 50 g / m 2, the porosity is 50%.

[0129] Example 3

[0130] The embodiment of the present application provides an epoxy resin adhesive modified by cenospheres and modified lignin, comprising the following components in parts by weight:

[0131] 100 parts of epoxy resin, 15 parts of cenospheres modified by KH-550, 5 parts of modified lignin;

[0132] The epoxy resin is E-44 epoxy resin (specifically EP epoxy resin E44 from Baling Petrochemical);

[0133] Among them, the preparation method of the modified lignin comprises the following steps:

[0134] Mix lignin with perchloric acid solution at room temperature (25 °C) with stirring for 30 min, and then react at 80 °C for 3 h. After the reaction is completed, adjust the pH of the reaction system to neutral with NaOH, and carry out vacuum distillation and collect the solid precipitate to obtain the modified lignin;

[0135] The mass ratio of lignin to perchloric acid solution is 1:10; the mass fraction of the perchloric acid solution (specifically an aqueous solution) is 65%;

[0136] The preparation method of the cenospheres modified by KH-550 comprises the following steps:

[0137] Add the silane coupling agent KH-550 to the ethanol aqueous solution to obtain a hydrolysis solution;

[0138] Add the cenospheres (the average particle size of the cenospheres is 150 μm) to the hydrolysis solution, stir for 3 h, filter, wash, and dry to obtain the cenospheres modified by the silane coupling agent;

[0139] The volume concentration of the ethanol aqueous solution is 80%;

[0140] The volume ratio of the silane coupling agent to the ethanol aqueous solution is 1:40;

[0141] The mass of the silane coupling agent is 1% of the mass of the cenospheres.

[0142] This embodiment also provides a preparation method of an integrated honeycomb composite material, comprising the following steps:

[0143] S1. Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics on the upper and lower surfaces of the honeycomb core;

[0144] S2. Immerse the glass fiber in the epoxy resin adhesive modified by cenospheres and modified lignin in Example 3 at room temperature (25 °C) to obtain an epoxy resin / glass fiber composite material. Among them, the amount of epoxy resin adhesive loaded on the glass fiber per square meter is 800 g on average, that is, the loading amount is 800 g / m 2 ;

[0145] S3. Stack the film skin, adhesive glass fiber composite material, honeycomb panel, adhesive glass fiber composite material, and film skin in sequence from bottom to top, and hot press and cure to obtain a honeycomb composite material;

[0146] The process parameters controlled by hot press curing are: curing pressure is 0.5 Mpa, temperature is 120 °C, and time is 40 min;

[0147] The film skin is a polyester film with a thickness of 0.1 mm;

[0148] The glass fiber is a medium-alkali glass fiber cloth with a grammage of 1080 g / m² (1080 g / m 2 ), and the thickness is 0.3 mm;

[0149] The honeycomb core is an aramid honeycomb core, the thickness of the aramid honeycomb core is 1.0 cm, the thickness of the non-woven fabric is 0.1 mm, and the grammage of the non-woven fabric is 50 g / m 2 , and the porosity is 50%;

[0150] Comparative Example 1

[0151] This comparative example provides an epoxy resin adhesive, including the following components in parts by weight: 100 parts of epoxy resin; the epoxy resin is E-44 epoxy resin (specifically EP epoxy resin E44 of Baling Petrochemical);

[0152] This comparative example also provides a preparation method of a honeycomb composite material, including the following steps:

[0153] S1. Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non-woven fabrics located on the upper and lower surfaces of the honeycomb core;

[0154] S2. Immerse the glass fiber in the epoxy resin adhesive of Comparative Example 1 at room temperature (25 °C) to obtain an epoxy resin / glass fiber composite material. Among them, the amount of epoxy resin adhesive loaded on the glass fiber per square meter is 800 g on average, that is, the loading amount is 800 g / m 2 ;

[0155] S3. Stack the film skin, adhesive glass fiber composite material, honeycomb panel, adhesive glass fiber composite material, and film skin in sequence from bottom to top, and hot press and cure to obtain a honeycomb composite material;

[0156] The process parameters controlled by hot pressing and curing are as follows: the curing pressure is 0.5 Mpa, the temperature is 120 °C, and the time is 50 min;

[0157] The film skin is a polyester film with a thickness of 0.1 mm;

[0158] The glass fiber is a medium-alkali glass fiber cloth with a grammage of 1080 g / m² (1080 g / m 2 ), and the thickness is 0.3 mm;

[0159] The honeycomb core is an aramid honeycomb core. The thickness of the aramid honeycomb core is 1.0 cm, the thickness of the non-woven fabric is 0.1 mm, and the grammage of the non-woven fabric is 50 g / m 2 , and the porosity is 50%.

[0160] Performance testing

[0161] Test the flat tensile strength, flexural strength and density of the honeycomb composites in Test Examples 1 to 3 and Comparative Example 1; among them, the flat tensile strength is tested according to GB / T 1452-2018, and the flexural strength is tested according to GB / T8812.2-2007.

[0162] The flat tensile strength of the honeycomb composite prepared in Example 1 is 1.10 MPa, and the density is 1.12 g / cm 3 , and the flexural strength is 17.5 MPa.

[0163] The flat tensile strength of the honeycomb composite prepared in Example 2 is 1.12 MPa, and the density is 1.18 g / cm 3 , and the flexural strength is 18.1 MPa.

[0164] The flat tensile strength of the honeycomb composite prepared in Example 3 is 1.01 MPa, and the density is 1.20 g / cm 3 , and the flexural strength is 17.8 MPa.

[0165] The flat tensile strength of the honeycomb composite prepared in Comparative Example 1 is 0.80 MPa, and the density is 1.18 g / cm 3 , and the flexural strength is 14.1 MPa.

[0166] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An epoxy resin adhesive modified by cenospheres and modified lignin, characterized in that, It includes the following components: epoxy resin, cenospheres, modified lignin; Among them, the preparation method of the modified lignin includes the following steps: Mix lignin with perchloric acid solution, react at 70 - 80 °C for 2 - 3 h. After the reaction is completed, adjust the pH of the reaction system to neutral, carry out vacuum distillation and collect the solid precipitate to obtain modified lignin.

2. The epoxy resin adhesive modified by cenospheres and modified lignin as described in claim 1, characterized in that, The mass ratio of the lignin to the perchloric acid solution is 1:(10 - 12); The mass fraction of the perchloric acid solution is 60 - 72%; 3. The epoxy resin adhesive modified by cenospheres and modified lignin as claimed in claim 1, wherein The mass ratio of the epoxy resin to the cenospheres is (3 - 10):1; The mass of the modified lignin is 5 - 15% of the mass of the epoxy resin; 4. The epoxy resin adhesive modified by cenospheres and modified lignin as described in claim 1, characterized in that, The particle size of the cenospheres is 100 - 250 μm; The epoxy resin includes at least one of bisphenol A epoxy resin and E - 44 epoxy resin; 5. The epoxy resin adhesive modified by cenospheres and modified lignin as claimed in claim 1, wherein The cenospheres are cenospheres modified with a silane coupling agent, and the modification method of the cenospheres includes: Add the silane coupling agent to the ethanol aqueous solution to obtain a hydrolysis solution; Add the cenospheres to the hydrolysis solution, stir for 2 - 3 h, filter, wash, and dry to obtain cenospheres modified with a silane coupling agent; Among them, the silane coupling agent includes at least one of KH - 550, KH - 792, KH - 602, KH - 560, KH - 570, KH - 580, KH - 590, KH - 902; The volume concentration of the ethanol aqueous solution is 75 - 90%; The volume ratio of the silane coupling agent to the ethanol aqueous solution is 1:(40 - 50); The mass of the silane coupling agent is 1 - 2% of the mass of the cenospheres; 6. The epoxy resin adhesive modified by cenospheres and modified lignin according to any one of claims 1 to 5, characterized in that, It also includes an auxiliary agent, and the auxiliary agent includes at least one of a curing agent, an anti - aging agent, and a flame retardant; 7. A preparation method of an integrated honeycomb composite material, characterized in that, It includes the following steps: Provide a film skin and a honeycomb panel; the honeycomb panel includes a honeycomb core and non - woven fabrics on the upper and lower surfaces of the honeycomb core; Immerse glass fiber in the epoxy resin adhesive modified with cenospheres and modified lignin according to any one of claims 1 - 6 to obtain an adhesive glass fiber composite material; Stack the film skin, the adhesive glass fiber composite material, the honeycomb panel, the adhesive glass fiber composite material, and the film skin from bottom to top in sequence, and carry out hot - pressing curing to obtain a honeycomb composite material; 8. The preparation method of the honeycomb composite material according to claim 7, characterized in that, The process parameters controlled for the hot - pressing curing are: the curing pressure is 0.3 - 0.6 Mpa, the temperature is 115 - 125 °C, and the time is 20 - 60 min; 9. The preparation method of the honeycomb composite material according to claim 7, characterized in that, The film skin includes any one of a polyester film, a metal film, and a nylon film; The thickness of the film skin is 12 - 500 μm; The adhesive content in the adhesive glass fiber composite material is 500 - 1000 g / m 2 ; The thickness of the glass fiber is 0.2 - 0.4 mm; The thickness of the honeycomb panel is 1 - 2 cm, the thickness of the honeycomb core is 1 - 2 cm, the thickness of the non - woven fabric is 0.1 - 0.2 mm, and the porosity of the non - woven fabric is 40 - 60%; 10. A honeycomb composite material, characterized in that, It is prepared by using the preparation method according to any one of claims 7 - 9.

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