Organosilicon oligomer intercalated montmorillonite and preparation method thereof, and modified hot-melt boron phenolic resin and preparation method thereof

Abstract

The preparation method of the hot-melt boron phenolic resin comprises the following steps: adding aldehyde into a mixture of phenol in a molten state and organosilicone oligomer intercalated montmorillonite, adjusting the pH value, reacting at 50-70 DEG C for 1-5 hours, adding a boric acid derivative, reacting at the temperature of 50-70 DEG C for 1-5 hours, filtering, washing and drying to obtain the modified organosilicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin, and drying to obtain the modified organosilicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin modified hot-melt boron phenolic resin modified hot-melt boron phenolic resin modified hot-melt boron phenolic resin modified hot-melt boron phenolic resin modified hot-melt boron phenolic resin. Reacting at 90-120 DEG C, then adding a modifier, uniformly stirring, and then carrying out reduced pressure distillation until the gelation time of the product at 180 + / -1 DEG C is 120-320 seconds. According to the hot-melt boron phenolic resin prepared by the preparation method disclosed by the invention, the distance between two-dimensional lamellas of montmorillonite is increased by using an organic silicon oligomer intercalation layer, and the phenolic resin is subjected to in-situ polycondensation among montmorillonite layers due to the larger interlayer distance, so that the formation of a montmorillonite exfoliated structure is realized; meanwhile, due to the lamellar structure of the montmorillonite, a heat transfer channel is prolonged, and the initial thermal decomposition temperature, the thermal stability and the mechanical property of the cured resin are improved.

Description

Technical Field

[0001] The present invention belongs to the field of phenolic resins, and in particular, relates to an organosilicon oligomer intercalated montmorillonite and a preparation method thereof, and a modified hot-melt boron phenolic resin and a preparation method thereof. Background Art

[0002] In order to meet the increasingly harsh service environment of new rocket engines and aerospace vehicles, higher requirements are put forward for the ablation of thermal protection materials and the application of heat flow environment. Resin-based composite materials used in the field of ablation should have outstanding high temperature resistance and ablation resistance. Compared with ordinary phenolic resins, the boron element in the boron phenolic resin matrix blocks the easily oxidized phenolic hydroxyl groups in the phenolic resin, forming a high-energy BOC bond; at the same time, the boron compound itself cross-links to form a BOB structure, and a B2O3 liquid protective film is formed during the pyrolysis process, which further improves the high temperature resistance of the resin. In summary, boron phenolic resin has higher heat resistance, ablation resistance and mechanical properties, can be used as an excellent ablation-resistant material matrix, and has the potential to be used in rockets, missiles, spacecraft and other fields. However, boron phenolic resin contains a large number of trifunctional boron structures, which makes its synthesis process difficult to control and the product is brittle, limiting the large-scale production and application of boron phenolic resin. Two-dimensional materials can form covalent interactions with the resin matrix and a certain meshing effect with the cross-linked network, which can hinder the movement of molecular chains to a certain extent, which is beneficial to improving the rigidity of the matrix; at the same time, when subjected to external impact forces, the introduction of two-dimensional materials can change the direction of cracks, while improving the crack bridging effect, forming a shear band with the thermosetting resin, thereby improving the toughness of the matrix. However, two-dimensional nanomaterials are affected by van der Waals forces and have a serious tendency to self-aggregate, which may reduce or even deteriorate the performance of the resin.

[0003] Polymer / layered silicate materials are organic-inorganic materials with organic polymers as the matrix and layered silicates as the dispersed phase. The interlayer spacing of silicates is used to insert polymer macromolecules into them to form micro-nano-scale layered materials. However, montmorillonite has a serious tendency to self-aggregate, and a large number of inorganic ions between the layers are hydrophilic. It is difficult for polymer monomers to be inserted into unmodified layered inorganic materials and then polymerized. Therefore, it is necessary to introduce organosilicon oligomers to increase the interlayer spacing to avoid agglomeration. Organic cations also make montmorillonite organic and lipophilic, making it possible to insert or strip polymers.

[0004] As ablative thermal protection materials, fiber-reinforced phenolic resin-based composite materials have the advantages of easy molding, short processing cycle and good thermal insulation performance. They are mainly prepared by phenolic resin prepreg winding-hot pressing molding process. There are two main methods for preparing phenolic prepreg: solution impregnation and hot melt impregnation. Compared with the solution impregnation method (wet method), the hot melt prepreg method (dry method) has low volatile content, controllable resin content, and good batch stability. The prepared composite material has low porosity, strong mechanical properties and good dimensional stability. The hot melt prepreg method requires that the resin has good moldability at room temperature, can be bent arbitrarily, and can maintain low viscosity for a long time at the melting temperature.

[0005] Traditional boron phenolic resin has a high degree of cross-linking and a large molecular weight. At the melting temperature, the viscosity of the resin increases rapidly, it is easy to gel, and the film is brittle and easy to fall off, which makes it difficult to meet the requirements of the hot melt prepreg processing technology.

[0006] In view of this, there is an urgent need to seek an improved method for preparing hot-melt boron phenolic resin, which can optimize the synthesis process, simplify the synthesis steps, improve the thermal and mechanical properties of the resin and meet the requirements of hot-melt processing technology to adapt to the wider application of boron phenolic resin. Summary of the invention

[0007] In order to optimize the thermal and mechanical properties of resins in the prior art and meet the process requirements of hot melt processing, the present invention provides a silicone oligomer intercalated montmorillonite and a preparation method, a modified hot melt boron phenolic resin and a preparation method. The modified hot melt boron phenolic resin prepared by the method has low brittleness and good film-forming properties and can meet the requirements of the hot melt prepreg processing technology.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A method for preparing organosilicon oligomer intercalated montmorillonite comprises the following steps: ball-milling a mixture of an organosilicon oligomer, montmorillonite and water to obtain an organosilicon oligomer intercalated montmorillonite; Furthermore, the mass ratio of the organosilicon oligomer to the montmorillonite is 1-10:10-1.

[0009] Furthermore, the organosilicon oligomer is one or more of methyl silicone oil, phenyl silicone oil, amino silicone oil, epoxy silicone oil and polyether modified silicone oil with a molecular weight of 1000-5000 g / mol; The montmorillonite is one or more of organic quaternary ammonium salt intercalated montmorillonite, sodium-based montmorillonite, calcium-based montmorillonite and acid-activated montmorillonite.

[0010] Furthermore, the ball milling speed is 100-400 rpm, and the time is 10-30 h.

[0011] A silicone oligomer intercalated montmorillonite.

[0012] A method for preparing a silicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin comprises the following steps: The molten phenol and the organosilicon oligomer intercalated montmorillonite are uniformly mixed, and then aldehyde is added, the pH is adjusted to 7-8, and the reaction is carried out at 50-70°C for 1-5h to obtain an intermediate product; Add a boric acid derivative to the intermediate product, react at 90-120° C. for 0.5-6 hours, add a modifier after reduced pressure distillation, stir evenly, and then perform reduced pressure distillation until the gel time of the product at 180±1° C. reaches 120-320 seconds to obtain a silicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin.

[0013] Furthermore, the molar ratio of phenol, aldehyde and boron compound is 10-200:12-300:1-60; the weight ratio of phenol, organosilicon oligomer intercalated montmorillonite and modifier is 100:1-10:1-30.

[0014] Furthermore, the molar ratio of phenol, aldehyde and boron compound is 100:110-150:1-60; the weight ratio of phenol, organosilicon oligomer intercalated montmorillonite and modifier is 100:1-5:1-20.

[0015] Further, the phenol is one or both of monohydric phenol and dihydric phenol; the boron compound is boric acid or a boric acid derivative; Further, the monohydric phenol is one or more of phenol, o-cresol, m-cresol, p-cresol, α-naphthol, β-naphthol and 4-hydroxymethylphenol; the dihydric phenol is one or more of o-catechol, resorcinol, hydroquinone, bisphenol A and bisphenol F; Boric acid derivatives include one or more of p-boric acid, phenylboric acid, hydroxymethylphenylboric acid, hydroxyphenylboric acid, biphenylboric acid, borax, sodium borate, diphenylboric acid, methylphenylboric acid, dimethylphenylboric acid, methoxyphenylboric acid, isopropylphenylboric acid, ethoxyphenylboric acid, 1,4-phenyldiboric acid, ethylphenylboric acid, butylphenylboric acid, 2,4,6-triphenylboroxine and 3-hydroxyphenylboric acid.

[0016] Further, the aldehyde is one or more of formaldehyde, acetaldehyde, butyraldehyde, glutaraldehyde, trioxymethylene and paraformaldehyde; Modifiers are polyvinyl acetal, thermoplastic phenolic resin, polyamide, epoxy resin E 20 Epoxy resin E 44 Epoxy resin E 51 Epoxy resin F 44 With epoxy resin F 51 One or more of; The pH is adjusted using one or more of NaOH, NH3·H2O and Ba(OH)2.

[0017] A silicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin with an initial decomposition temperature T 5% The temperature is 426-500℃, the residual carbon rate is 72.1-80.0%, the viscosity at 70℃ is 28693-66548mPa·s, and the impact strength is 2.6-3.8KJ·m -2 , the bending strength is 57.2-64.6MPa.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention firstly introduces the organosilicon oligomer into the interlayer of montmorillonite by ball milling intercalation, increases the interlayer spacing of silicate sheets, and changes the montmorillonite from hydrophilic to lipophilic, solves the agglomeration problem of montmorillonite, and makes it easier for the monomer to polymerize and delaminate between the layers. Thus, the montmorillonite is dispersed in the resin matrix at a micro-nano scale, and a high-strength and tough boron phenolic / montmorillonite material is obtained.

[0019] In the in-situ synthesis, the addition of modifiers thermoplastic phenolic resin and epoxy resin effectively solves the problems of poor film-forming and high brittleness of traditional boron phenolic resin. The obtained resin is non-sticky, non-slag-dropping, and bendable at room temperature. It can maintain low viscosity for a long time at the coating temperature and is a resin suitable for hot melt prepreg process. The trifunctional boron structure in the boron phenolic resin of the present invention provides a large number of cross-linking sites for the resin matrix while also improving the brittleness of the resin; in addition, the presence of a large number of rigid benzene ring structures in the boron phenolic resin requires toughening and modification of the boron phenolic resin. The present invention applies nano effect and strong interface interaction between nanoparticles and polymer matrix to prepare boron phenolic aldehyde / montmorillonite nanocomposite materials to meet the application scenarios of high strength and high toughness of boron phenolic resin; at the same time, in order to solve the self-polymerization tendency of montmorillonite due to van der Waals force, it is easier for monomers to enter the silicate interlayer polymerization and peeling, and organic silicon oligomers are used to insert the montmorillonite interlayer in advance by means of ball milling, which increases the interlayer spacing of montmorillonite, and also changes montmorillonite from hydrophilic to lipophilic, making polymer insertion and peeling possible. Therefore, phenol and aldehyde in the system smoothly enter the montmorillonite layer of the organic silicon oligomer intercalation through diffusion and intermolecular force, and initiate polymerization between the layers. The huge heat released during polymerization overcomes the Coulomb force between the montmorillonite layers to peel it off, so that montmorillonite is dispersed in the resin matrix at nanometer scale, and a high-strength and tough boron phenolic aldehyde / montmorillonite material, i.e., a modified hot-melt boron phenolic resin, is obtained, and the problem that the traditional boron phenolic resin is large in brittleness and poor in film-forming property is overcome, and it is difficult to meet the requirements of the hot-melt prepreg process is solved.

[0020] The synthesizing method of the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin prepared by the present invention is simple, the reaction process is stable and controllable, and the process is environmentally friendly, and it is suitable for large-scale production, especially in the fields of ablation heat protection, refractory materials, etc. It has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The montmorillonite and the organosilicon oligomer intercalated montmorillonite in the present invention are scanned at a speed of 3°·min -1 , X-ray diffraction pattern in the scanning range of 0-10°.

[0022] Figure 2 1 and 2 are TGA curves of the boron phenolic resin cured products in Example 8, Comparative Example 1 and Comparative Example 2 of the present invention under a nitrogen atmosphere.

[0023] Figure 3 It is a mechanical data diagram of the carbon fiber composite material prepared by the boron phenolic resin in Example 8, Comparative Example 1 and Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0025] The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin provided by the present invention comprises the following components in terms of molar ratio: Phenol 10-200 parts; Aldehyde 12-300 parts; 1-60 parts of a boron compound; The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin also includes organosilicon oligomer intercalated montmorillonite and a modifier, and the relationship between the amount of the phenol and the resin is as follows: Phenol 100 parts by weight; 1-10 parts by weight of organosilicon oligomer intercalated montmorillonite; Modifier 1-30 parts by weight; Preferably, the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin comprises the following components in molar ratio: Phenol 100 parts; Aldehyde 110-150 parts; 1-40 parts of a boron compound; Preferably, the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin further comprises organosilicon oligomer intercalated montmorillonite and a modifier; the dosage relationship of the organosilicon oligomer intercalated montmorillonite, the modifier and the phenol is as follows: Phenol 100 parts by weight; 1-5 parts by weight of organosilicon oligomer intercalated montmorillonite; Modifier 1-20 parts by weight; Preferably, the phenol is one or both of monohydric phenol and dihydric phenol; the monohydric phenol is one or more of phenol, o-cresol, m-cresol, p-cresol, α-naphthol, β-naphthol and 4-hydroxymethylphenol; the dihydric phenol is one or more of o-catechol, m-cresol, hydroquinone, bisphenol A and bisphenol F.

[0026] The aldehyde is one or more of formaldehyde, acetaldehyde, butyraldehyde, glutaraldehyde, trioxymethylene and paraformaldehyde; The boron compound is boric acid or a boric acid derivative; The boric acid derivatives include one or more of phenylboric acid, hydroxymethylphenylboric acid, hydroxyphenylboric acid, biphenylboric acid, borax, sodium borate, diphenylboric acid, methylphenylboric acid, dimethylphenylboric acid, methoxyphenylboric acid, isopropylphenylboric acid, ethoxyphenylboric acid, 1,4-phenyldiboric acid, ethylphenylboric acid, butylphenylboric acid, 2,4,6-triphenylboroxine and 3-hydroxyphenylboric acid.

[0027] The modifier includes polyvinyl acetal, thermoplastic phenolic resin, polyamide, epoxy resin E 20 Epoxy resin E 44 Epoxy resin E 51 Epoxy resin F 44 With epoxy resin F 51 One or more of .

[0028] The method for preparing the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of the present invention comprises the following steps: Preparation of organosilicon oligomer intercalated montmorillonite: According to the selected fraction, the organosilicon oligomer, montmorillonite and deionized water are mixed in a certain proportion and put into a planetary ball mill for ball milling at 100-400rpm for 10-30h. After the ball milling, 5-10 times the deionized water of the product is added for washing and centrifugation. The lower layer of sediment is taken out, dried and ground to obtain organosilicon oligomer intercalated montmorillonite; wherein the mass ratio of organosilicon oligomer to montmorillonite is 1-10:10:1; the organosilicon oligomer includes one or more of methyl silicone oil, phenyl silicone oil, amino silicone oil, epoxy silicone oil and polyether modified silicone oil (Jinan Xinglong Chemical Co., Ltd.) with a molecular weight of 1000-5000g / mol. The montmorillonite includes one or more of organic quaternary ammonium salt intercalated montmorillonite, sodium montmorillonite, calcium montmorillonite and acid activated montmorillonite of Dachanghua Jiahui Zhengxing Chemical Shanghai Co., Ltd.

[0029] Preparation of hot-melt boron phenolic resin modified by organosilicon oligomer intercalated montmorillonite: In a molten state of phenol, an organosilicon oligomer intercalated montmorillonite is added and mixed for 1-5 hours, then a certain weight portion of aldehyde is added, the pH is adjusted to 7-8 by an alkaline catalyst, and the reaction is carried out at 50-70°C for 1-5 hours to obtain an intermediate product; then a selected portion of a boric acid derivative is added to the intermediate product, and the reaction is carried out at 90-120°C for 0.5-6 hours, and after the by-products are removed by reduced pressure distillation, a modifier is added thereto, stirred, and mixed for 0.5 hours, and then vacuum dehydration is continued and the gel time is tested. When the gel time of the resin at 180±1°C reaches 120-320s, the reaction is terminated to obtain an organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin.

[0030] The alkaline catalyst is one or more of NaOH, NH3·H2O and Ba(OH)2.

[0031] Preferably, the method for preparing the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin specifically comprises the following steps: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 1-5 hours, and then adding the aldehyde, adjusting the pH to 7-8 using an alkaline catalyst, slowly heating to 50-70° C., reacting for 1-5 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boric acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 100-120° C. for 0.5-6 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 50-80°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 120-320s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0032] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods.

[0033] Unless otherwise specified, the materials, reagents, etc. used in the following embodiments can be obtained from commercial sources.

[0034] Example 1 The organosilicon oligomer intercalated montmorillonite of this embodiment includes the following components by weight: 10 parts of montmorillonite, 10 parts of organosilicon oligomer and 20 parts of deionized water.

[0035] Wherein, the montmorillonite is sodium montmorillonite, and the organosilicon oligomer is epoxy functionalized organosilicon oligomer (DCHJH Chemical Shanghai Co., Ltd.), with a molecular weight of 1000-2000 g / mol.

[0036] The preparation method is as follows: Take montmorillonite, silicone oligomer and deionized water in selected portions, add a certain mass of porcelain balls and put them into a planetary ball mill at 200 rpm, ball mill for 20 hours, take out the product, add deionized water to wash, centrifuge, take out the lower layer of precipitate, dry and grind to obtain silicone oligomer intercalated montmorillonite.

[0037] Example 2 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 100 parts of phenol, 150 parts of aldehyde and 20 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 5 parts of organosilicon oligomer intercalated montmorillonite (prepared in Example 1) and 20 parts of modifier.

[0038] The phenol is monohydric phenol, the monohydric phenol is phenol; the aldehyde is paraformaldehyde; the boron compound is paraboric acid; the modifier is a thermoplastic phenolic resin and E in a mass ratio of 9:1. 51 Epoxy resin mixture.

[0039] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly raising the temperature to 70° C., reacting for 4 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), reacting under reflux at 110° C. for 3 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 50-80°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 120-320s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0040] Example 3 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 100 parts of phenol, 140 parts of aldehyde, and 25 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 5 parts of organosilicon oligomer intercalated montmorillonite, and 20 parts of modifier.

[0041] The phenol is monohydric phenol, the monohydric phenol is phenol; the aldehyde is paraformaldehyde; the boron compound is paraboric acid; the modifier is thermoplastic phenolic resin and E 51 Epoxy resin mixture.

[0042] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly raising the temperature to 70° C., reacting for 3 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), reacting under reflux at 110° C. for 2 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 70°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 120-320s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0043] Example 4 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components in molar ratio: 100 parts of phenol, 110 parts of aldehyde, and 5 parts of boron compound; in weight ratio, 100 parts of phenol, 3 parts of organosilicon oligomer intercalated montmorillonite, and 20 parts of modifier.

[0044] The phenol is monohydric phenol, the monohydric phenol is phenol; the aldehyde is paraformaldehyde; the boron compound is paraboric acid; the modifier is thermoplastic phenolic resin and E 51 Epoxy resin mixture.

[0045] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly raising the temperature to 70° C., reacting for 4 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boric acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 100° C. for 4 hours to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 50-80°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 120-320s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0046] Example 5 The low free formaldehyde hot-melt boron phenolic resin of this embodiment includes the following components by molar ratio: 100 parts of phenol, 120 parts of aldehyde, and 25 parts of boron compound; by weight ratio, 100 parts of phenol, 3 parts of organosilicon oligomer intercalated montmorillonite, and 15 parts of modifier.

[0047] The phenol is monohydric phenol, the monohydric phenol is phenol; the aldehyde is paraformaldehyde; the boron compound is paraboric acid; the modifier is thermoplastic phenolic resin and E 51 Epoxy resin mixture.

[0048] Its preparation method is: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing at 50° C. for 3 h, then adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 65° C., reacting for 4 h, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 95° C. for 4 hours to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 70°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 200s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0049] Example 6 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components in molar ratio: 100 parts of phenol, 130 parts of aldehyde, and 10 parts of boron compound; in weight ratio, 100 parts of phenol, 2 parts of organosilicon oligomer intercalated montmorillonite, and 10 parts of modifier.

[0050] Wherein, the phenol is phenol; the aldehyde is paraformaldehyde powder; the boron compound is boric acid; the modifier is thermoplastic phenolic resin and E 44 Epoxy resin mixture.

[0051] Its preparation method is: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing at 50° C. for 2 h, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 60° C., reacting for 5 h, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), reacting under reflux at 110° C. for 3 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 70°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 200s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0052] Example 7 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 100 parts of phenol, 120 parts of aldehyde, and 15 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 5 parts of organosilicon oligomer intercalated montmorillonite, and 20 parts of modifier.

[0053] Wherein, the phenol is phenol; the aldehyde is paraformaldehyde powder; the boron compound is boric acid; the modifier is thermoplastic phenolic resin and E 44 Epoxy resin mixture.

[0054] Its preparation method is: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing at 50° C. for 3 hours, adding the aldehyde in two portions, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 70° C., reacting for 4 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 90° C. for 6 hours to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 60°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 240s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0055] Example 8 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 100 parts of phenol, 120 parts of aldehyde, and 30 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 5 parts of organosilicon oligomer intercalated montmorillonite, and 20 parts of modifier.

[0056] Wherein, the phenol is phenol; the aldehyde is paraformaldehyde powder; the boron compound is boric acid; the modifier is thermoplastic phenolic resin and E 51 Epoxy resin mixture.

[0057] Its preparation method is: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing at 50° C. for 3 hours, adding the aldehyde in two portions, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 70° C., reacting for 5 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 105° C. for 3.5 hours to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 60°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 300s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0058] Example 9 The organosilicon oligomer intercalated montmorillonite of this embodiment includes the following components by weight: 1 part of montmorillonite, 10 parts of organosilicon oligomer and 20 parts of deionized water.

[0059] Wherein, the montmorillonite is organic quaternary ammonium salt intercalated montmorillonite, and the organosilicon oligomer is methyl silicone oil with a molecular weight of 1000-2000 g / mol.

[0060] The preparation method is as follows: Montmorillonite, silicone oligomer and deionized water are taken in selected portions, a certain mass of porcelain balls are added and put into a planetary ball mill at 100 rpm for 30 hours, the product is taken out, deionized water is added for washing, centrifugation is performed, the lower precipitate is taken out, dried and ground to obtain silicone oligomer intercalated montmorillonite.

[0061] Example 10 The organosilicon oligomer intercalated montmorillonite of this embodiment includes the following components by weight: 10 parts of montmorillonite, 2 parts of organosilicon oligomer and 20 parts of deionized water.

[0062] The montmorillonite is calcium-based montmorillonite, the organosilicon oligomer is a mixture of amino silicone oil and polyether modified silicone oil (Jinan Xinglong Chemical Co., Ltd.) in a mass ratio of 1:1, and the molecular weight of the amino silicone oil and the polyether modified silicone oil is 1000-2000 g / mol.

[0063] The preparation method is as follows: Take montmorillonite, silicone oligomer and deionized water in selected portions, add a certain mass of porcelain balls and put them into a planetary ball mill at 300 rpm, ball mill for 15 hours, take out the product, add deionized water for washing, centrifuge, take out the lower layer of precipitate, dry and grind to obtain silicone oligomer intercalated montmorillonite.

[0064] Embodiment 11 The organosilicon oligomer intercalated montmorillonite of this embodiment includes the following components by weight: 10 parts of montmorillonite, 1 part of organosilicon oligomer and 20 parts of deionized water.

[0065] The montmorillonite is a mixture of acid activated montmorillonite (Dachang Hua Jiahui Zhengxing Chemical Shanghai Co., Ltd.) and organic quaternary ammonium salt intercalated montmorillonite in a mass ratio of 1:1, and the organosilicon oligomer is phenyl silicone oil with a molecular weight of 1000-2000g / mol.

[0066] The preparation method is as follows: Montmorillonite, organosilicon oligomer and deionized water are taken in selected portions, a certain mass of porcelain balls are added and put into a planetary ball mill at 400 rpm for 10 hours, the product is taken out, deionized water is added for washing, centrifugation is performed, the lower precipitate is taken out, dried and ground to obtain organosilicon oligomer intercalated montmorillonite.

[0067] Example 12 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 10 parts of phenol, 12 parts of aldehyde and 1 part of boron compound; calculated by weight ratio, 100 parts of phenol, 1 part of organosilicon oligomer intercalated montmorillonite (prepared in Example 1) and 1 part of modifier.

[0068] The phenol is a monophenol, which is o-benzoyl phenol; the aldehyde is a mixture of trioxymethylene and polyoxymethylene in a molar ratio of 1:1; the boron compound is phenylboric acid; and the modifier is polyvinyl alcohol acetal in a mass ratio of 1:1.

[0069] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 70° C., reacting for 2 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 90° C. for 6 hours to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 50°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 120 seconds, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0070] Example 13 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 200 parts of phenol, 300 parts of aldehyde and 40 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 5 parts of organosilicon oligomer intercalated montmorillonite (prepared in Example 1) and 30 parts of modifier.

[0071] The phenol is a dihydric phenol, which is a mixture of catechol and bisphenol A in a molar ratio of 1:1; the aldehyde is a mixture of butyraldehyde and glutaraldehyde in a molar ratio of 1:1; the boron compound is a mixture of hydroxymethyl phenylboric acid and hydroxyphenylboric acid in a molar ratio of 1:1; the modifier is a mixture of polyamide and epoxy resin E in a mass ratio of 1:1 20 mixture.

[0072] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 7 using an alkaline catalyst, slowly heating to 50° C., reacting for 5 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boric acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 120° C. for 0.5 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 80°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 320 seconds, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0073] Embodiment 14 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 100 parts of phenol, 140 parts of aldehyde and 20 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 8 parts of organosilicon oligomer intercalated montmorillonite (prepared in Example 1) and 20 parts of modifier.

[0074] The phenol is a monohydric phenol, which is a mixture of 4-hydroxymethylphenol and β-naphthol in a molar ratio of 1:1; the aldehyde is acetaldehyde; the boron compound is a mixture of biphenylboric acid, borax, sodium borate and diphenylboric acid in a molar ratio of 1:1:1:1; the modifier is an epoxy resin E in a mass ratio of 1:1 51 With epoxy resin F 44 mixture.

[0075] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 70° C., reacting for 1 hour, and obtaining an intermediate product A; (2) adding a selected amount of a boric acid derivative to the intermediate product A obtained in step (1), and reacting under reflux at 100° C. for 3 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 60°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 180s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0076] Embodiment 15 The organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of this embodiment includes the following components, calculated by molar ratio: 110 parts of phenol, 110 parts of aldehyde and 60 parts of boron compound; calculated by weight ratio, 100 parts of phenol, 10 parts of organosilicon oligomer intercalated montmorillonite (prepared in Example 1) and 10 parts of modifier.

[0077] The phenol is a monohydric phenol, which is a mixture of 4-hydroxymethylphenol and β-naphthol in a molar ratio of 1:1; the aldehyde is formaldehyde; the boron compound is a mixture of methylphenylboric acid, dimethylphenylboric acid, methoxyphenylboric acid, isopropylphenylboric acid, ethoxyphenylboric acid, 1,4-phenyldiboric acid, ethylphenylboric acid, butylphenylboric acid, 2,4,6-triphenylboroxine and 3-hydroxyphenylboric acid in a molar ratio of 1:1:1:11:1:1:1:1; the modifier is epoxy resin F 51 .

[0078] The preparation method is as follows: (1) taking the phenol in selected portions, heating the phenol until it is melted, adding the selected portions of the organosilicon oligomer intercalated montmorillonite prepared by ball milling under stirring conditions, mixing for 3 hours, adding the aldehyde, adjusting the pH to 8 using an alkaline catalyst, slowly heating to 65° C., reacting for 3 hours, and obtaining an intermediate product A; (2) adding a selected amount of a boronic acid derivative to the intermediate product A obtained in step (1), reacting under reflux at 110° C. for 2 h to obtain an intermediate product B; (3) subjecting the intermediate product obtained in step (2) to reduced pressure distillation at 90-110° C. to remove water generated by the reaction; (4) When the temperature reaches 70°C in step (3), add the modifier, stir and mix for 30 minutes, then continue to vacuum dehydrate and test the gel time. When the gel time of the resin at 180±1°C reaches 260s, the reaction is completed to obtain a hot-melt boron phenolic resin modified by silicone oligomer intercalated montmorillonite.

[0079] Comparative Example 1 The hot-melt boron phenolic resin of this comparative example has the same composition as that of Example 8, except that the montmorillonite is not intercalated with organosilicon oligomer, and is prepared by the same method as that of Example 8.

[0080] Comparative Example 2 The boron phenolic resin in this comparative example has the same composition as that in Example 8, except that the organosilicon oligomer intercalated montmorillonite is not included, and is prepared by the same method as in Example 8.

[0081] Effect verification: In order to verify the technical effect of the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin of the present invention, the boron phenolic resins prepared in Examples 2-8, Comparative Examples 1 and 2 were subjected to the following experiments: Montmorillonite and montmorillonite intercalated with organosilicon oligomer were taken and their interlayer spacing was tested by X-ray diffraction.

[0082] Take the boron phenolic resin to be tested, and after curing, use a thermogravimetric analyzer (TG) to test the residual carbon rate of the resin at 800°C to simply judge the thermal stability of the resin.

[0083] The thermal and mechanical properties of the resin matrix of the embodiment and the comparative example and the viscosity at the hot melt processing temperature are shown in the following table. The boron phenolic resin to be tested is pressed into a carbon fiber composite material according to the national standard GB / T 9341-2008, and the impact strength and tensile strength of the prepared composite material are tested on a universal testing machine.

[0084] The experimental results are as follows:

[0085] The temperature at which the weight loss is 5% is defined as the initial decomposition temperature T 5% .

[0086] According to the above table, the modified boron phenolic resin has a suitable viscosity at 70°C, a certain fluidity and processing window, and is suitable for hot melt prepreg method.

[0087] The crystal structure of unmodified montmorillonite and montmorillonite intercalated with organosilicon oligomers was characterized by X-ray diffractometer. The data are as follows: Figure 1 After ball milling and intercalation, the interlayer spacing of silicates increases, which avoids the agglomeration of two-dimensional nanosheets and is conducive to the polymer monomers entering the interlayer polymerization reaction to obtain molecular-level fused nanocomposites, effectively improving the thermal and mechanical properties of the resin.

[0088] The thermal stability of the resin was analyzed by thermogravimetric analysis. The thermogravimetric curves of the residual amount of the boron phenolic resin used in Example 8, Comparative Examples 1 and 2 under a nitrogen atmosphere as a function of temperature are shown in FIG. Figure 2 As shown in Figure 2, it can be seen that the carbon residue rate and T of the resin at 800°C before and after the use of silicone oligomer intercalation 5％ All have improved.

[0089] The resin pressed carbon fiber composite materials prepared by Example 8 of the present invention and Comparative Examples 1 and 2 were tested for mechanical properties of the composite materials using a universal testing machine. The data are as follows: Figure 3 As shown. Figure 3It can be seen that after adding silicone oligomer intercalated montmorillonite modified boron phenolic resin, the flexural strength and interlaminar shear strength of the composite material are significantly improved. The reason is that the introduction of two-dimensional materials can change the crack direction, while improving the crack bridging effect, forming a shear band between the thermosetting resin, thereby improving the toughness of the matrix.

[0090] The use of organosilicon oligomer intercalation in the hot-melt boron phenolic resin prepared by the present invention increases the spacing between the two-dimensional montmorillonite layers, and the larger interlayer spacing enables the in-situ polycondensation of the phenolic resin between the montmorillonite layers to realize the formation of a montmorillonite exfoliation structure; at the same time, the lamellar structure of the montmorillonite prolongs the heat transfer channel and increases the initial thermal decomposition temperature of the resin cured product. The synthesis process of such hot-melt boron phenolic resin modified by organosilicon oligomer intercalation montmorillonite is stable and controllable, and the thermal stability and mechanical properties of the modified resin are significantly improved.

[0091] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. However, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0092] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A method for preparing organosilicon oligomer intercalated montmorillonite, characterized in that: The following steps are involved: The mixture of the organosilicon oligomer, montmorillonite and water is ball-milled to obtain the organosilicon oligomer intercalated montmorillonite.

2. The method for preparing organosilicon oligomer intercalated montmorillonite according to claim 1, characterized in that: The mass ratio of the organosilicon oligomer to the montmorillonite is 1-10:10-1.

3. The method for preparing organosilicon oligomer intercalated montmorillonite according to claim 1, characterized in that: The organosilicon oligomer is one or more of methyl silicone oil, phenyl silicone oil, amino silicone oil, epoxy silicone oil and polyether modified silicone oil with a molecular weight of 1000-5000 g / mol; The montmorillonite is one or more of organic quaternary ammonium salt intercalated montmorillonite, sodium-based montmorillonite, calcium-based montmorillonite and acid-activated montmorillonite.

4. The method for preparing organosilicon oligomer intercalated montmorillonite according to claim 1, characterized in that: The ball milling speed is 100-400 rpm and the time is 10-30 hours.

5. An organosilicon oligomer intercalated montmorillonite prepared according to the method according to any one of claims 1 to 4.

6. A method for preparing a hot-melt boron phenolic resin modified by an organosilicon oligomer intercalated montmorillonite, characterized in that: The following steps are involved: The molten phenol is mixed evenly with the organosilicon oligomer intercalated montmorillonite prepared by any one of claims 1 to 4, and then aldehyde is added, the pH is adjusted to 7-8, and the reaction is carried out at 50-70° C. for 1-5 hours to obtain an intermediate product; Add a boric acid derivative to the intermediate product, react at 90-120° C. for 0.5-6 hours, add a modifier after reduced pressure distillation, stir evenly, and then perform reduced pressure distillation until the gel time of the product at 180±1° C. reaches 120-320 seconds to obtain a silicone oligomer intercalated montmorillonite modified hot-melt boron phenolic resin.

7. The method for preparing the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin according to claim 6, characterized in that: The molar ratio of phenol, aldehyde and boron compound is 10-200:12-300:1-60; the weight ratio of phenol, organosilicon oligomer intercalated montmorillonite and modifier is 100:1-10:1-30; aldehyde is one or more of formaldehyde, acetaldehyde, butyraldehyde, glutaraldehyde, trioxymethylene and polyformaldehyde; Modifiers are polyvinyl acetal, thermoplastic phenolic resin, polyamide, epoxy resin E 20 Epoxy resin E 44 Epoxy resin E 51 Epoxy resin F 44 With epoxy resin F 51 One or more of; The pH is adjusted using one or more of NaOH, NH3·H2O and Ba(OH)2.

8. The method for preparing the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin according to claim 7, characterized in that: The phenol is one or both of monohydric phenol and dihydric phenol; the boron compound is boric acid or a boric acid derivative.

9. The method for preparing the organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin according to claim 8, characterized in that: The monohydric phenol is one or more of phenol, o-cresol, m-cresol, p-cresol, α-naphthol, β-naphthol and 4-hydroxymethylphenol; the dihydric phenol is one or more of o-catechol, resorcinol, hydroquinone, bisphenol A and bisphenol F; Boric acid derivatives include one or more of p-boric acid, phenylboric acid, hydroxymethylphenylboric acid, hydroxyphenylboric acid, biphenylboric acid, borax, sodium borate, diphenylboric acid, methylphenylboric acid, dimethylphenylboric acid, methoxyphenylboric acid, isopropylphenylboric acid, ethoxyphenylboric acid, 1,4-phenyldiboric acid, ethylphenylboric acid, butylphenylboric acid, 2,4,6-triphenylboroxine and 3-hydroxyphenylboric acid.

10. An organosilicon oligomer intercalated montmorillonite modified hot-melt boron phenolic resin prepared according to the method of claim 6, characterized in that: Initial decomposition temperature T 5% The temperature is 426-500℃, the residual carbon rate is 72.1-80.0%, the viscosity at 70℃ is 28693-66548mPa·s, and the impact strength is 2.6-3.8KJ·m -2 , the bending strength is 57.2-64.6MPa.

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