Preparation method and application of open hole reinforcement material

Abstract

The present invention relates to the technical field of reinforcing materials, and specifically to a preparation method of an open-pore reinforcing material and its application. The preparation method of the open-pore reinforcing material specifically includes the following steps: Step 1: Mix epoxy resin, modifier, modified filler, defoamer, curing agent, and butanone to obtain a modified epoxy resin impregnation liquid; Step 2: Soak the fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out, and solidify it to obtain the open-pore reinforcing material. The application of the open-pore reinforcing material specifically includes the following steps: Step 1: Cut the open-pore reinforcing material according to the shape and size of the opening position and the aperture size; Step 2: When the workpiece is formed to the set layer thickness, use an adhesive to bond the cut open-pore reinforcing material to the opening position, and apply a certain pressure, and then wait for the adhesive to solidify and firmly bond it to achieve local reinforcement of the workpiece.

Description

Technical Field

[0001] The invention relates to the technical field of reinforcing materials, in particular to a preparation method of an open-cell reinforcing material and application thereof. Background Art

[0002] In industry, the main methods of reinforcing composite materials are adding reinforcing ribs and increasing wall thickness. Adding reinforcing ribs is a method of using local surface reinforcement to improve the overall strength and stiffness of the workpiece. This method has been widely used in the manufacture of workpieces in various technical fields, including aerospace, automobiles, chemicals, construction, and civil equipment. It is a simple and effective reinforcement method; increasing wall thickness is an overall reinforcement of the surface to improve the overall strength and stiffness of the workpiece. The increase in material wall thickness will lead to an increase in volume and thus an increase in overall mass, and excessive mass is not conducive to the daily use of the workpiece.

[0003] With the increasing development of industrialization, the distribution of holes on workpieces is becoming more and more dense and extensive. The placement of reinforcement ribs is often based on the symmetrical distribution of the axis, which makes it difficult to take care of all the holes. The openings that are not located at the reinforcement rib position often become weak positions during the use of the material. Therefore, finding a method to strengthen the through holes between reinforcement ribs has become an important issue that needs to be solved urgently.

[0004] In the process of implementing the embodiments of the present invention, the inventors found that the background technology has at least the following defects: (1) ordinary reinforcing ribs are difficult to cover all the openings on the workpiece, leaving stress concentration areas on the surface of the workpiece; (2) the local reinforcement method will affect the external dimensions of the workpiece and increase the weight of the workpiece, which is not conducive to the daily use of the material.

[0005] In summary, the present invention provides an opening reinforcement material, which is used for openings not covered by reinforcing ribs. It can achieve local reinforcement without affecting the size and other aspects of the workpiece, which is of great significance. Summary of the invention

[0006] The object of the present invention is to provide a preparation method of an open-cell reinforcement material and its application to solve the problems raised in the prior art.

[0007] To achieve the above-mentioned purpose, the first aspect of the present invention provides a method for preparing an open-cell reinforcement material, and the specific technical scheme is as follows:

[0008] A method for preparing an open-hole reinforcement material comprises the following steps:

[0009] Step 1: mixing epoxy resin, modifier, modified filler, defoamer, curing agent and butanone to obtain modified epoxy resin impregnation liquid;

[0010] Step 2: Soak the fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out, and solidify it to obtain the open-pore reinforcement material.

[0011] Furthermore, the preparation method of the modifier is as follows: under an inert gas atmosphere, organic silicon and N,N'-carbonyldiimidazole are dissolved in dimethyl sulfoxide, stirred and heated to 65-85°C for reaction for 1-5 hours, and then 20-30wt% of a dimethyl sulfoxide solution of polyetheramine is added to the reaction system, and the stirring reaction is continued for 3-12 hours to terminate the reaction; (2) after the reaction system in (1) is cooled to room temperature, deionized water is added thereto, stirred and mixed, and then dichloromethane is added to the reaction system, and the lower organic phase is extracted and collected, and the process is repeated 2-3 times; (3) the organic phase collected in (2) is washed with brine for 1-5 times, and then dried with anhydrous sodium sulfate, and finally dichloromethane is removed by rotary evaporation to obtain the modifier.

[0012] Furthermore, the mass ratio of the organic silicon, N,N'-carbonyldiimidazole and polyetheramine is (0.8-1):1:(1.5-2).

[0013] Furthermore, the preparation method of the modified filler is: add the filler, silicone and anhydrous ethanol into a container, ultrasonically disperse for 5 to 15 minutes, heat to 40 to 70°C and stir for 1 to 6 hours, finally filter, wash with deionized water for 1 to 3 times, and dry to obtain the modified filler.

[0014] Furthermore, the ratio of the filler, silicone and anhydrous ethanol is 1g: (0.05-0.1)mL: 10mL.

[0015] Furthermore, the filler includes but is not limited to any one of calcium carbonate, carbon black, silicon dioxide, and coal powder, and its particle size is ≤40nm.

[0016] Furthermore, the organosilicon includes but is not limited to any one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane; the organosilicon used in the modifier and the modified filler is preferably the same organosilicon.

[0017] Furthermore, the modified epoxy resin impregnation liquid includes the following components: by weight, 50-65 parts of epoxy resin, 15-23 parts of modifier, 10-18 parts of modified filler, 4-8 parts of defoamer, 4-8 parts of curing agent, and 50 parts of butanone.

[0018] Furthermore, the curing agent includes but is not limited to one or more combinations of triethanolamine curing agent, isocyanate curing agent, anhydride curing agent and ammonium phosphate curing agent.

[0019] Furthermore, the mixing parameters are: mixing temperature is 50-80° C., and mixing time is 0.5-2 h.

[0020] Furthermore, the reinforcing fibers in the fiber cloth include but are not limited to any one or more combinations of carbon fibers, glass fibers, aramid fibers, and ultra-high molecular weight polyethylene fibers.

[0021] Furthermore, the specific process of the curing is: placing the impregnated fiber in a vacuum drying oven, curing it at 110-120° C. for 10-30 minutes, and then heating it to 150-170° C. for curing for 1-3 hours.

[0022] Furthermore, the thickness of the open hole reinforcement material is 2±0.1 mm.

[0023] Common open hole reinforcement materials that do not have a significant impact on the size and quality of the workpiece are generally fiber cloths that are impregnated with resin and cured. The inventors noticed that during the curing process of the resin, the volume of the resin will shrink due to factors such as volatilization, that is, shrinkage stress will be generated in the fiber cloth. If the shrinkage stress is too large, stress concentration will occur, which will lead to a decrease in the adhesion of the resin. For example, the epoxy resin used in common open hole reinforcement materials has the characteristics of poor toughness and heat resistance, so this situation is more likely to occur.

[0024] Based on this, the present invention uses carbonyl diimidazole as a bridge, firstly reacts the amino group on the organosilicon with one imidazole group of carbonyl diimidazole, then reacts the amino group on the polyetheramine with another imidazole group of carbonyl diimidazole, and then combines the polyetheramine and organosilicon together to prepare a modifier, and the epoxy resin is modified by the modifier to improve its adhesion to the fiber cloth, thereby better reinforcing the opening. The modifier contains a long flexible chain of polyetheramine, which can toughen the epoxy resin, and the excellent toughness can effectively weaken the influence of epoxy resin curing shrinkage, thereby avoiding the decrease of resin adhesion; and the organosilicon chain end can produce a bonding force with the fiber on the subsequent impregnated fiber cloth, thereby improving the adhesion of the epoxy resin. That is, under the synergistic effect of polyetheramine and organosilicon, the modified epoxy resin impregnation liquid can adhere firmly to the fiber cloth after curing, and finally act on the opening of the workpiece, thereby achieving strong reinforcement of the opening. In addition, polyetheramine also has a curing effect and can promote the curing of epoxy resin.

[0025] In the present invention, fillers with a particle size of ≤40 nm are further introduced into the epoxy resin, which can give the epoxy resin a toughening and reinforcement effect; in order to prevent the fine fillers from agglomerating in the epoxy resin and affecting the performance of the epoxy resin, silicone is used in the scheme to modify the fillers, and the modified fillers have good dispersibility; in addition, amino groups are introduced into the modified fillers, which can promote the curing of the epoxy resin together with the modifier.

[0026] The second aspect of the present invention provides that the opening reinforcement material has a reinforcement performance and is suitable for application at the opening of a workpiece to achieve local reinforcement of the workpiece; the specific technical solution is as follows:

[0027] An application of an open hole reinforcement material, the specific application process includes the following steps:

[0028] Step 1: Cut the opening reinforcement material according to the opening position, shape, size and aperture size;

[0029] Step 2: When the workpiece is formed to the set layer thickness, use adhesive to bond the cut opening reinforcement material to the opening position and apply a certain pressure. After the adhesive is cured, it is firmly bonded to achieve local reinforcement of the workpiece.

[0030] Furthermore, the shape of the open hole reinforcement material cut out includes but is not limited to a combination of one or more of a rectangle, a regular polygon, a circle, and a triangle.

[0031] Furthermore, the adhesive includes but is not limited to one or more combinations of epoxy resin, phenolic resin, urea-formaldehyde resin, melamine formaldehyde resin, silicone resin, furan resin, unsaturated polyester, acrylic resin, polyimide, polybenzimidazole, phenolic-polyvinyl acetal, phenolic-polyamide, phenolic-epoxy resin, and epoxy-polyamide.

[0032] Furthermore, the curing parameters of the adhesive are: curing temperature is 20-250° C., and curing time is 0.5-36 hours.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. In the present invention, the epoxy resin is modified by the modifier and the modified filler to enhance its toughness and reinforcement effect, so that it can better reinforce the opening part of the workpiece;

[0035] 2. The hole reinforcement material prepared by the present invention can effectively reinforce the hole part of the workpiece. Compared with the unreinforced workpiece, it can greatly increase the compressive stress load that the material can withstand, thereby improving the service life and safety of the workpiece during service and operation;

[0036] 3. The open hole reinforcement material prepared by the present invention can reinforce the weak part of the workpiece without increasing the overall thickness and external dimensions of the workpiece. Compared with the local reinforcement method of increasing the wall thickness, it can greatly reduce the weight of the workpiece and reduce the cost. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that the purchasers of all raw materials involved in the present invention include, without any special restrictions, illustratively:

[0039] The epoxy resin brand is Phoenix brand, model is E51, CAS number is 61788-97-4, viscosity is 8000~15000mPas, purchased from Nantong Xingchen Synthetic Materials Co., Ltd.

[0040] γ-Aminopropyltriethoxysilane with a purity of 99%, N,N'-carbonyldiimidazole with a purity of 99%, dimethyl sulfoxide with a purity of 99%, dichloromethane with a purity of 99%, carbon black with an average particle size of 30 nm and an average particle size of 80 nm with a purity of 99%, triethylamine with a purity of 99%, and butanone with a purity of 99% were all purchased from Hubei Yongkuo Technology Co., Ltd.;

[0041] The polyetheramine model is D400, purity is 99%, product number is P8 15987, purchased from Maclean Co., Ltd.

[0042] Anhydrous sodium sulfate with a purity of 98% was purchased from Jinjinle (Hunan) Chemical Co., Ltd.;

[0043] The defoamer model is BYK-A 530, purchased from Shanghai Buding Chemical Co., Ltd.;

[0044] Number of portions in the following examples: Each portion is 10 g.

[0045] Example 1: A method for preparing an open-hole reinforcement material:

[0046] Step 1: Preparation of modified epoxy resin impregnation solution:

[0047] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 14.4 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, and the mixture was stirred and heated to 70°C for reaction for 3 hours. Then, a 25 wt% dimethyl sulfoxide solution of polyetheramine (prepared by dissolving 28.8 parts of polyetheramine in dimethyl sulfoxide) was added to the reaction system, and the reaction was continued for 10 hours with stirring to terminate the reaction. (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, and the mixture was stirred and mixed. Then, 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected, and the reaction was repeated 3 times. (3) The organic phase collected in (2) was washed 3 times with a 10 wt% sodium chloride aqueous solution, and then dried with anhydrous sodium sulfate. Finally, the dichloromethane was removed by rotary evaporation to obtain a modifier.

[0048] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 12 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0049] 3. Add 60 parts of E51 epoxy resin, 18 parts of modifier, 14 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0050] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0051] Embodiment 2: A method for preparing an open hole reinforcement material:

[0052] Step 1: Preparation of modified epoxy resin impregnation solution:

[0053] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 12.8 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, and the mixture was stirred and heated to 65°C for reaction for 1 hour. Then, a 25 wt% dimethyl sulfoxide solution of polyetheramine (prepared by dissolving 24 parts of polyetheramine in dimethyl sulfoxide) was added to the reaction system, and the reaction was continued for 3 hours with stirring. The reaction was terminated. (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, and the mixture was stirred and mixed. Then, 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected. The process was repeated 3 times. (3) The organic phase collected in (2) was washed 3 times with a 10 wt% sodium chloride aqueous solution, and then dried with anhydrous sodium sulfate. Finally, the dichloromethane was removed by rotary evaporation to obtain a modifier.

[0054] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 7.5 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0055] 3. Add 60 parts of E51 epoxy resin, 15 parts of modifier, 10 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0056] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0057] Embodiment 3: A method for preparing an open hole reinforcement material:

[0058] Step 1: Preparation of modified epoxy resin impregnation solution:

[0059] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 16 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, stirred and heated to 85°C for reaction for 5 hours, and then a 25 wt% dimethyl sulfoxide solution of polyetheramine (prepared by dissolving 32 parts of polyetheramine in dimethyl sulfoxide) was added to the reaction system, and the reaction was continued with stirring for 12 hours to terminate the reaction; (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, stirred and mixed, and then 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected, and the process was repeated 3 times; (3) The organic phase collected in (2) was washed 3 times with a 10 wt% sodium chloride aqueous solution, and then dried with anhydrous sodium sulfate, and finally dichloromethane was removed by rotary evaporation to obtain a modifier;

[0060] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 15 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0061] 3. Add 60 parts of E51 epoxy resin, 23 parts of modifier, 18 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0062] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2.1 mm.

[0063] Based on Example 1, a control experiment was carried out, specifically Comparative Examples 1 to 6, as described below:

[0064] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: no modifier is added, and other processes remain unchanged, specifically:

[0065] A method for preparing an open hole reinforcement material:

[0066] Step 1: Preparation of modified epoxy resin impregnation solution:

[0067] 1. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 12 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0068] 2. Add 60 parts of E51 epoxy resin, 14 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0069] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 1.9 mm.

[0070] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: no modified carbon black is added, and other processes remain unchanged, specifically:

[0071] A method for preparing an open hole reinforcement material:

[0072] Step 1: Preparation of modified epoxy resin impregnation solution:

[0073] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 14.4 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, and the mixture was stirred and heated to 70°C for reaction for 3 hours. Then, a 25 wt% dimethyl sulfoxide solution of polyetheramine (prepared by dissolving 28.8 parts of polyetheramine in dimethyl sulfoxide) was added to the reaction system, and the reaction was continued for 10 hours with stirring to terminate the reaction. (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, and the mixture was stirred and mixed. Then, 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected, and the reaction was repeated 3 times. (3) The organic phase collected in (2) was washed 3 times with a 10 wt% sodium chloride aqueous solution, and then dried with anhydrous sodium sulfate. Finally, the dichloromethane was removed by rotary evaporation to obtain a modifier.

[0074] 2. Add 60 parts of E51 epoxy resin, 18 parts of modifier, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0075] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0076] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: no modification treatment is performed on the epoxy resin, and other processes remain unchanged, specifically:

[0077] A method for preparing an open hole reinforcement material:

[0078] Step 1: 1. Add 60 parts of E51 epoxy resin, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60° C. for 1 hour to obtain an epoxy resin impregnation solution;

[0079] The glass fiber cloth was immersed in the epoxy resin impregnation liquid, and after it was soaked, it was taken out and placed in a vacuum drying oven. After curing at 110°C for 30 minutes, the temperature was raised to 160°C for curing for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0080] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: no organic silicon is added in the preparation of the modifier, and other processes remain unchanged, specifically:

[0081] A method for preparing an open hole reinforcement material:

[0082] Step 1: Preparation of modified epoxy resin impregnation solution:

[0083] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 57.6 parts of polyetheramine and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, and the mixture was heated to 70°C with stirring for 10 hours to terminate the reaction; (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, and the mixture was stirred and mixed. Then 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected, and the process was repeated 3 times; (3) The organic phase collected in (2) was washed 3 times with a 10 wt% aqueous solution of sodium chloride, and then dried with anhydrous sodium sulfate. Finally, the dichloromethane was removed by rotary evaporation to obtain a modifier;

[0084] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 12 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0085] 3. Add 60 parts of E51 epoxy resin, 18 parts of modifier, 14 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0086] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0087] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustments: no polyetheramine is added in the preparation of the modifier, and other processes remain unchanged, specifically:

[0088] A method for preparing an open hole reinforcement material:

[0089] Step 1: Preparation of modified epoxy resin impregnation solution:

[0090] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, dissolve 28.8 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole in 50 parts of dimethyl sulfoxide, stir and heat to 70°C for 3 hours, and terminate the reaction; (2) After the reaction system in (1) is cooled to room temperature, add 100 parts of deionized water thereto, stir and mix, then add 60 mL of dichloromethane to the reaction system, extract and collect the lower organic phase, and repeat 3 times; (3) Wash the organic phase collected in (2) 3 times with a 10 wt% sodium chloride aqueous solution, then dry it with anhydrous sodium sulfate, and finally remove dichloromethane by rotary evaporation to obtain a modifier;

[0091] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 30 nm), 12 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0092] 3. Add 60 parts of E51 epoxy resin, 18 parts of modifier, 14 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0093] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2 mm.

[0094] Comparative Example 6: Comparative Example 6 is based on Example 1, with the following adjustments: the particle size of the modified carbon black is greater than 40 nm (the average particle size is 80 nm), and other processes remain unchanged, specifically:

[0095] A method for preparing an open hole reinforcement material:

[0096] Step 1: Preparation of modified epoxy resin impregnation solution:

[0097] 1. Preparation of a modifier: (1) Under a nitrogen atmosphere, 14.4 parts of γ-aminopropyltriethoxysilane and 16 parts of N,N'-carbonyldiimidazole were dissolved in 50 parts of dimethyl sulfoxide, and the mixture was stirred and heated to 70°C for reaction for 3 hours. Then, a 25 wt% dimethyl sulfoxide solution of polyetheramine (prepared by dissolving 28.8 parts of polyetheramine in dimethyl sulfoxide) was added to the reaction system, and the reaction was continued for 10 hours with stirring to terminate the reaction. (2) After the reaction system in (1) was cooled to room temperature, 100 parts of deionized water was added thereto, and the mixture was stirred and mixed. Then, 60 mL of dichloromethane was added to the reaction system, and the lower organic phase was extracted and collected, and the reaction was repeated 3 times. (3) The organic phase collected in (2) was washed 3 times with a 10 wt% sodium chloride aqueous solution, and then dried with anhydrous sodium sulfate. Finally, the dichloromethane was removed by rotary evaporation to obtain a modifier.

[0098] 2. Preparation of modified carbon black: 15 parts of carbon black (average particle size of 80 nm), 12 mL of γ-aminopropyltriethoxysilane, and 1.5 L of anhydrous ethanol were added into a container, ultrasonically dispersed for 10 min, heated to 50 ° C and stirred for 5 h, and finally filtered, washed with deionized water 3 times, and dried to obtain modified carbon black;

[0099] 3. Add 60 parts of E51 epoxy resin, 18 parts of modifier, 14 parts of modified carbon black, 7 parts of BYK-A 530 defoamer, 6 parts of triethylamine and 50 parts of butanone into a kneader and mix at 60°C for 1 hour to obtain a modified epoxy resin impregnation solution;

[0100] Step 2: Soak the glass fiber cloth in the modified epoxy resin impregnation liquid, wait for it to be soaked, take it out and place it in a vacuum drying oven, cure it at 110°C for 30 minutes, and then heat it to 160°C for 3 hours to obtain an open-pore reinforcement material with a thickness of 2.1 mm.

[0101] 1. Performance test: The tensile strength and hardness of the open hole reinforcement materials prepared in the above embodiments and comparative examples were tested. The specific test results are as follows:

[0102] Table 1

[0103]

[0104] Result analysis: From the data in Table 1 above, it can be seen that the present invention greatly improves the performance (tensile strength, hardness, etc.) of the open-cell reinforcement material by modifying the epoxy resin with a modifier and a modified filler (modified carbon black). The higher the tensile strength and hardness, the tighter the epoxy resin is combined with the fiber cloth, that is, the better the adhesion of the resin on the open-cell reinforcement material to the fiber cloth, the better the reinforcement performance; in particular, Example 1 shows more excellent performance than other examples, with a tensile strength of 13.6 MPa and a hardness of 78 HA, which is the best example of the present invention.

[0105] Application: The opening reinforcement material prepared in Example 1 is cut into a rectangle of 30 mm × 70 mm, and an epoxy resin adhesive (E51 epoxy resin and triethanolamine are mixed in a mass ratio of 20:1) is coated on one side of the opening reinforcement material; then the side coated with the adhesive is pasted to the opening position of the workpiece, fixed by a fixing device, and a pressure of 5 MPa is applied; finally, it is placed at room temperature for curing for 24 hours to complete the workpiece opening reinforcement.

[0106] 2. Performance test: A 10t compressive load was applied to the reinforced parts of the workpieces obtained in the above application and the reinforced parts of the workpieces obtained by traditional thickening methods to detect the difference between the two technologies, as shown in Table 2 below:

[0107] Table 2

[0108]

[0109] Result analysis: When the opening of a workpiece is reinforced with the opening reinforcement material prepared by the present invention, the microstrain at the opening portion is smaller, which is 1200με, and the reinforcement effect is better.

[0110] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing an open-cell reinforcement material, characterized in that: The specific steps include: Step 1: mixing epoxy resin, modifier, modified filler, defoamer, curing agent and butanone to obtain modified epoxy resin impregnation liquid; Step 2: Soak the fiber cloth in a modified epoxy resin impregnation solution, wait for it to be soaked, take it out, and solidify it to obtain an open-pore reinforcement material; The preparation method of the modifier is as follows: in an inert gas atmosphere, organic silicon and N, N'-carbonyl diimidazole are dissolved in dimethyl sulfoxide, stirred and heated to 65-85°C for reaction for 1-5 hours, then 20-30wt% of a dimethyl sulfoxide solution of a polyetheramine is added to the reaction system, the stirring reaction is continued for 3-12 hours, the reaction is terminated, and the modifier is obtained through separation and purification; wherein the mass ratio of organic silicon, N, N'-carbonyl diimidazole and polyetheramine is (0.8-1):1:(1.5-2); the organic silicon includes any one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane and γ-aminopropylmethyldiethoxysilane; The preparation method of the modified filler is as follows: filler, organosilicon and anhydrous ethanol are added into a container, ultrasonically dispersed for 5 to 15 minutes, heated to 40 to 70° C. and stirred for 1 to 6 hours, and finally filtered, washed and dried to obtain the modified filler; wherein the ratio of filler, organosilicon and anhydrous ethanol is 1 g: (0.05 to 0.1) mL: 10 mL; organosilicon includes any one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane and γ-aminopropylmethyldiethoxysilane; the filler includes any one of calcium carbonate, carbon black, silicon dioxide and coal powder, and the particle size thereof is ≤40 nm; The modified epoxy resin impregnation liquid comprises the following components: by weight, 50-65 parts of epoxy resin, 15-23 parts of modifier, 10-18 parts of modified filler, 4-8 parts of defoamer, 4-8 parts of curing agent and 50 parts of butanone.

2. The method for preparing an open-hole reinforcing material according to claim 1, characterized in that: The reinforcing fibers in the fiber cloth include any one or more combinations of carbon fibers, glass fibers, aramid fibers, and ultra-high molecular weight polyethylene fibers.

3. The method for preparing an open-pore reinforcing material according to claim 1, characterized in that: The mixing parameters are: mixing temperature of 50-80° C., mixing time of 0.5-2 h; the specific process of curing is: placing the impregnated fibers in a vacuum drying oven, curing at 110-120° C. for 10-30 min, and then heating to 150-170° C. for curing for 1-3 h.

4. An application of an open hole reinforcement material, characterized in that: The open hole reinforcement material prepared by the preparation method according to any one of claims 1 to 3 is suitable for application at the opening of a workpiece to achieve local reinforcement of the workpiece; the specific application includes the following steps: Step 1: Cut the opening reinforcement material according to the opening position, shape, size and aperture size; Step 2: When the workpiece is formed to the set layer thickness, use adhesive to bond the cut opening reinforcement material to the opening position and apply a certain pressure. After the adhesive is cured, it is firmly bonded to achieve local reinforcement of the workpiece.

5. The use of an open hole reinforcement material according to claim 4, characterized in that: The cut shape of the open hole reinforcing material includes a combination of one or more of a rectangle, a regular polygon, a circle, and a triangle.

6. The use of an open hole reinforcement material according to claim 4, characterized in that: The adhesive includes one or more combinations of epoxy resin, phenolic resin, urea-formaldehyde resin, melamine formaldehyde resin, silicone resin, furan resin, unsaturated polyester, acrylic resin, polyimide, polybenzimidazole, phenolic-polyvinyl acetal, phenolic-polyamide, phenolic-epoxy resin, and epoxy-polyamide.

7. The use of an open hole reinforcement material according to claim 4, characterized in that: The curing parameters of the adhesive are: curing temperature of 20 to 250° C., and curing time of 0.5 to 36 hours.

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